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SDLRC - Scientific Articles all years by Author - V


The Sheahan Diamond Literature Reference Compilation
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcementscalled the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Resource Center
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Media/Corporate References by Name for all years
A B C D-Diam Diamonds Diamr+ E F G H I J K L M N O P Q R S T U V W X Y Z
Tips for Users
Posted/Published Reference CodesThe SDLRC provides 3 types of references identified in the reference code. DS for scientific article, DM for a media article, and DC for a corporate announcement. Consider DS0512-0001. The DS stands for "diamond scientific". 05 stands for 2005, the year the reference was posted. 12 represents the month the reference was posted. For all years prior to 2015 the default month is 12. -0001 is the reference's identifier and it does not mean anything. The number below the refence code, ie 2015, is the year the article was published. Note that the posted year may sometimes be later than the published year.
Sort OrderReferences are sorted by the "author" name and when the reference was posted to the compilation.
Most RecentIf the reference code is highlighted yellow, the reference was made available through the most recent monthly compilation of new literature. Use this to check out new references. When new references are posted, we make it our priority to track down an online link and obtain an abstract. With regard to older references, tracking down an abstract and an online link is a work in progress.
Link to external location of article: If the title has a link, it means we have found a location online where you can either retrieve the full article free, or purchase access to it. The Sheahan Diamond Literature Service is not a technical article procurement service; if you want a restricted article, you must deal directly with the vendor who controls the copyright to the article.
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Author Index
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years - V
Posted/
Published
AuthorTitleSourceRegionKeywords
DS202111-1757
2021
V, R.Bedard, J.H., Troll, V,R., Deegan, F.M., Tegner, C., Saumur, B.M., Evenchick, C.A., Grasby, S.E., Dewing, K.High Arctic large igneous province alkaline rocks in Canada: evidence for multiple mantle components.Journal of Petrology, Vol. 62, 9, pp. 1-31. pdfCanada, Ellesmere Islandalkaline rocks

Abstract: The Cretaceous High Arctic Large Igneous Province (HALIP) in Canada, although dominated by tholeiites (135-90?Ma), contains two main groups of alkaline igneous rocks. The older alkaline rocks (?96?Ma) scatter around major fault and basement structures. They are represented by the newly defined Fulmar Suite alkaline basalt dykes and sills, and include Hassel Formation volcanic rocks. The younger alkaline group is represented by the Wootton Intrusive Complex (92•2-92•7?Ma), and the Audhild Bay Suite (83-73?Ma), both emplaced near the northern coast of Ellesmere Island. Fulmar Suite rocks resemble EM-type ocean island basalts (OIB) and most show limited crustal contamination. The Fulmar Suite shows increases of P2O5 at near-constant Ba-K-Zr-Ti that are nearly orthogonal to predicted fractionation- or melting-related variations, which we interpret as the result of melting composite mantle sources containing a regionally widespread apatite-bearing enriched component (P1). Low-P2O5 Fulmar Suite variants overlap compositionally with enriched HALIP tholeiites, and fall on common garnet lherzolite trace element melting trajectories, suggesting variable degrees of melting of a geochemically similar source. High-P2O5 Hassel Formation basalts are unusual among Fulmar rocks, because they are strongly contaminated with depleted lower crust; and because they involve a high-P2O5-Ba-Eu mantle component (P2), similar to that seen in alkali basalt dykes from Greenland. The P2 component may have contained Ba-Eu-rich hawthorneite and/or carbonate minerals as well as apatite, and may typify parts of the Greenlandic sub-continental lithospheric mantle (SCLM). Mafic alkaline Audhild Bay Suite (ABS) rocks are volcanic and hypabyssal basanites, alkaline basalts and trachy-andesites, and resemble HIMU ocean island basalts in having high Nb, low Zr/Nb and low 87Sr/86Sri. These mafic alkaline rocks are associated with felsic alkaline lavas and syenitic intrusions, but crustally derived rhyodacites and rhyolites also exist. The Wootton Intrusive Complex (WIC) contains geochemically similar plutonic rocks (alkali gabbros, diorites and anatectic granites), and may represent a more deeply eroded, slightly older equivalent of the ABS. Low-P2O5 ABS and WIC alkaline mafic rocks have flat heavy rare earth element (HREE) profiles suggesting shallow mantle melting; whereas High-P2O5 variants have steep HREE profiles indicating deeper separation from garnet-bearing residues. Some High-P2O5 mafic ABS rocks seem to contain the P1 and P2 components identified in Fulmar-Hassel rocks, whereas other samples trend towards possible High-P2O5 + Zr (PZr) and High-P2O5 + K2O (PK) components. We argue that the strongly alkaline northern Ellesmere Island magmas sampled mineralogically heterogeneous veins or metasomes in Greenlandic-type SCLM, which contained trace phases such as apatite, carbonates, hawthorneite, zircon, mica or richterite. The geographically more widespread apatite-bearing component (P1) could have formed part of a heterogeneous plume or upwelling mantle current that also generated HALIP tholeiites when melted more extensively, but may also have resided in the SCLM as relics of older events. Rare HALIP alkaline rocks with high K-Rb-U-Th fall on mixing paths implying strong local contamination from either Sverdrup Basin sedimentary rocks or granitic upper crust. However, the scarcity of potassic alkaline HALIP facies, together with the other trace element and isotopic signatures, provides little support for a ubiquitous fossil sedimentary subduction-zone component in the HALIP mantle source.
DS201810-2340
2018
V.G.krivovichev, Hazen, R.M. Krivovichev, V.G. Structural and chemical complexity of minerals: correlations and time evolution.European Journal of Mineralogy, Vol. 30, 2, pp. 231-236.Mantlegeochemistry

Abstract: Correlations between chemical and structural complexities of minerals were analysed using a total of 4962 datasets on the chemical compositions and 3989 datasets on the crystal structures of minerals. The amounts of structural and chemical Shannon information per atom and per unit cell or formula unit were calculated using the approach proposed by Krivovichev with no Hcorrection for the minerals with unknown H positions. Statistical analysis shows that there are strong and positive correlations (R 2 > 0.95) between the chemical and structural complexities and the number of different chemical elements in a mineral. Analysis of relations between chemical and structural complexities provides strong evidence that there is an overall trend of increasing structural complexity with the increasing chemical complexity. Following Hazen, four groups of minerals were considered that represent four eras of mineral evolution: "ur-minerals", minerals from chondritic meteorites, Hadean minerals, and minerals of the post-Hadean era. The analysis of mean chemical and structural complexities for the four groups demonstrate that both are gradually increasing in the course of mineral evolution. The increasing complexity follows an overall passive trend: more complex minerals form with the passage of geological time, yet the simpler ones are not replaced. The observed correlations between the chemical and structural complexities understood in terms of Shannon information suggest that, at a first approximation, chemical differentiation is a major force driving the increase of complexity of minerals in the course of geological time. New levels of complexity and diversifcation observed in mineral evolution are achieved through the chemical differentiation, which favours local concentrations of particular rare elements and creation of new geochemical environments.
DS1989-0832
1989
Vaag, O.V.Kryukov, A.V., Vaag, O.V., Mkrtychyan, A.K., et al.New pyrope bearing carbonate collector in the southern part of the TunguskasynecliseSoviet Geology and Geophysics, Vol. 30, No. 4, pp. 47-54RussiaGarnets, Petrology
DS1999-0760
1999
Vaan der Voo, R.Vaan der Voo, R., Spakman, W., Bijwaaard, H.Tehyan subducted slabs under IndiaEarth and Planetary Science Letters, Vol. 171, No. 1, Aug. 15, pp. 7-20.IndiaSubduction - slabs
DS1991-0625
1991
Vaasjoki, M.Gulson, B.L., Solomon, M., Vaasjoki, M., Both, R.Tasmania adrift?Australian Journal of Earth Sciences, Vol. 38, pp. 249-250TasmaniaTectonics, Structure
DS1991-0661
1991
Vaasjoki, M.Hanski, E., Huhma, H., Smolkin, V.F., Vaasjoki, M.The age of the ferropicritic volcanics and comagmatic nickel-bearing intrusion sat Pechenga, Kola Peninsula, U.S.S.R.Bulletin. Geological Society Finland, Vol. 62, pt. 2, pp. 123-133FinlandNickel, Pechenga
DS1995-0070
1995
Vaccari, N.E.Astini, R.A., Benedetto, J.L., Vaccari, N.E.The early Paleozoic evolution on the Argentine Pre Cordillera as a Laurentian rifted, drifted and collided terrane: a geodynamic model.Gsa Bulletin., Vol. 107, No. 3, pp. 253-73.ArgentinaTectonics
DS1995-0071
1995
Vaccari, N.E.Astini, R.A., Benedetto, J.L., Vaccari, N.E.The early Paleozoic evolution of the Argentine Pre Cordillera as a Laurentian rifted, drifted collidedGeological Society of America (GSA) Bulletin, Vol. 107, No. 3, March pp. 253-273ArgentinaTerrane, Geodynamics
DS2001-0133
2001
VaccaroBrigatti, M.F., Medici, L., Poppi, VaccaroCrystal chemistry of trioctahedral micas 1M from the Alto Paranaiba igneous provinceCanadian Mineralogist, Vol. 39, No. 5, Oct. pp. 1333-46.BrazilAlkaline rocks, Carbonatite
DS200912-0783
2009
Vaccaro, A.Vaccaro, A.A bourse, of course Toron to based diamond bourse launches but remains addresss-less.Diamonds in Canada Magazine, Northern Miner, June, pp. 17-18.CanadaDiamond bourse - brief overview
DS1996-0175
1996
Vaccaro, C.Brigatti, M.F., Medici, L., Saccani, E., Vaccaro, C.Crystal chemistry and petrologic significance of iron rich phlogopite From the Tapira carbonatite complex.American Mineralogist, Vol. 81, July-Aug. pp. 913-927.BrazilCarbonatite, Deposit -Tapira
DS200412-0117
2004
Vaccaro, C.Beccaluva, L., Bianchini, G., Bonadiman, C., Siena, F., Vaccaro, C.Coexisting anorogenic and subduction related metasomatism in mantle xenoliths from the Betic Cordillera ( southern Spain). TallaLithos, Vol. 75, 1-2, July pp. 67-87.Europe, SpainSubduction, trace element fingerprinting, petrogenetic
DS1999-0761
1999
Vacher, P.Vacher, P., Spakman, W., Wortel, M.J.R.Numerical tests on the seismic visibility of metastable minerals at subduction zones.Earth and Planetary Science Letters, Vol. 170, No. 3, Julu. 15, pp. 335-MantleGeophysics - seismics, Mineralogy
DS2001-1166
2001
Vacher, P.Trampert, J., Vacher, P., Vlaar, N.Sensitivities of seismic velocities to temperature, pressure and composition in the lower mantle.Physical Earth and Planetary Interiors, Vol. 124, No. 3-4, Aug. pp. 255-67.MantleGeophysics - seismics
DS2003-0198
2003
Vacher, P.Cammarano, F., Goes, S., Vacher, P., Giardini, D.Inferring upper mantle temperatures from seismic velocitiesPhysics of the Earth and Planetary Interiors, Vol. 138, 3-4, pp. 197-222.MantleGeophysics - seismics
DS2003-1099
2003
Vacher, P.Poupinet, G., Arndt, N., Vacher, P.Seismic tomography beneath stable tectonic regions and the origin and composition ofEarth and Planetary Science Letters, Vol. 212, 1-2, pp. 89-101.MantleTectonics
DS200412-0231
2004
Vacher, P.Bruneton, M., Pedersen, H.A., Vacher, P., Kukkonenen, I.T., Arndt, N.T., Funke, S., Friederich, W., Farra, V.Layered lithospheric mantle in the central Baltic Shield from surface waves and xenolith analysis.Earth and Planetary Science Letters, Vol. 226, 1-2, pp. 41-52.Baltic Shield, Norway, Finland, RussiaGeophysics - seismics, xenoliths
DS200412-0255
2003
Vacher, P.Cammarano, F., Goes, S., Vacher, P., Giardini, D.Inferring upper mantle temperatures from seismic velocities.Physics of the Earth and Planetary Interiors, Vol. 138, 3-4, pp. 197-222.MantleGeophysics - seismics
DS200412-1574
2003
Vacher, P.Poupinet, G., Arndt, N., Vacher, P.Seismic tomography beneath stable tectonic regions and the origin and composition of the continental lithospheric mantle.Earth and Planetary Science Letters, Vol. 212, 1-2, pp. 89-101.MantleGeophysics - seismics Tectonics
DS200912-0795
2009
Vacher, P.Verhoeven, O., MacQuet, A., Vacher, P., Rivoldini, A., Menvielle, M., Arrial, P.A., Chiblet, G., Tarits,P.Constraints on thermal state and composition of the Earth's lower mantle from electromagnetic impedances and seismic data.Journal of Geophysical Research, Vol. 114, B3, B03302.MantleGeophysics - seismics
DS1960-0631
1966
Vachette, M.Bardet, M.G., Vachette, M.Determination of the Ages of West African Kimberlites and An Interpretation from the Dates of the Different Diamondifero united States Events in the World.International Symposium AFR. GEOL. 3RD., CGLU, Report No. 6660, 88P.Sierra Leone, West Africa, Guinea, Central African RepublicGeochronology
DS1960-0632
1966
Vachette, M.Bardet, M.G., Vachette, M.Age Determinations of Kimberlites of West Africa and an Attempt to Interpret the Dating of Various Diamondiferous Occurrences in the World.French Geological Survey (BRGM) Report, No. 66, 59P.West Africa, Guinea, Sierra Leone, Liberia, Ivory CoastGeology, Geochronology
DS1993-1637
1993
Vacquier, V.Vacquier, V.Large hot mantle plumes create oceanic lithosphereAmerican Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 598.MantleOceanic lithosphere, Mantle plumes
DS1998-1504
1998
Vacquier, V.Vacquier, V.A theory of the origin of the Earth's internal heatTectonophysics, Vol. 291, No. 1-4, June 15, pp. 1-8.MantleCore, Melt
DS201709-2009
2017
Vaczi, T.Kaldos, R., Guzmics, T., Vaczi, T., Berkesi, M., Dankhazi, Z., Szabo, C.3D Raman mapping of melt inclusions in Kerimasi alkaline and carbonatite rocks.Goldschmidt Conference, abstract 1p.Africa, Tanzaniadeposit - Kerimasi

Abstract: The use of confocal HR-Raman mapping opens new perspectives in studying melt inclusions. Our major goal is to show advantages of this powerful technique through case studies carried out on alkaline and carbonatite rocks of Kerimasi volcano (East African Rift). Raman spectrometry is one of the few methods that enable qualitative nondestructive analysis of both solid and fluid phases, therefore it is widely used for the identification of minerals and volatiles within melt and fluid inclusions. For better understanding of petrogenetic processes in carbonatite systems it is essential to find all mineral phases in the melt inclusions trapped in intrusive or volcanic rocks. Previous Raman spectroscopic point measurements in melt inclusions revealed the presence of daughter phases (e.g. alkali carbonates, hydrocarbonates) [1] but utilizing Raman mapping on them even provides information on their size, shape and distribution. Raman 3D mapping were applied on unheated multiphase melt inclusions of intrusive and volcanic rocks with high spatial resolution (XY plane < 1 micron) with a depth scan (Z step) as low as 0.5 micron at every XY point, parallel to the surface of the host minerals. Analysis below the surface of the host mineral is especially useful because we can avoid the loss of sensitive (e.g. water soluble) phases and contamination of the melt inclusions, moreover unexposed melt inclusions are suitable for further analytical measurements (e.g. EPMA, microthermometry). By scanning multiple layers 2D or 3D Raman images can be gained, thus we can get an insight into post entrapment crystallization processes that contribute to a more precise description of the evolution of alkaline and carbonatite rocks.
DS201503-0147
2014
Vadaszi, E.Hainschwang, T., Notari, F., Vadaszi, E.The Rhodesian Star: an exceptional asteriated diamond.The Journal of Gemmology, Vol. 34, 4, pp. 306-315.Africa, ZimbabweDiamonds notable
DS201911-2526
2019
Vadillo, I.Giampouras, M., Garrido, C.J., Zwicker, J., Vadillo, I., Smrzka, D., Bach, W., Peckmann, J., Jemenez, P., Benavente, J., Garcia-Ruiz, J.M.Geochemistry and mineralogy of serpentinization driven hyperalkaline springs in the Ronda peridotite.Lithos, doi 10.1016/j.lithos.2019.105215, 75p. PdfEurope, Spaindeposit - Ronda

Abstract: We present a detailed study of the water geochemistry, mineralogy and textures in serpentinization-related hyperalkaline springs in the Ronda peridotites. Ronda waters can be classified into hyperalkaline fluids and river waters that are broadly similar to Ca2+-OH- and Mg2+-HCO3- water types described in serpentinite-hosted alkaline springs elsewhere. At the discharge sites of the fluids (fractures or human made outlets) and ponds along the fluid flow paths, the fluids are hyperalkaline (10.9 < pH < 12) and characterized by low Mg and high Na, K, Ca, and Cl concentrations. River waters, occurring near the spring sites, are mildly alkaline (8.5 < pH < 8.9) and enriched in Mg and DIC compared to Na, K, Ca and Cl. The chemistry of Ronda Mg-HCO3 river waters is likely due to the hydrolysis of ferromagnesian peridotite minerals in equilibrium with the atmosphere by infiltrated meteoric water and shallow groundwater in the serpentinized peridotite. The Ronda Ca-OH hyperalkaline fluids are generated by the combination of low temperature serpentinization reactions from infiltrated surface Mg-HCO3 river waters —or Ca-HCO3 waters from near karst aquifers— and deep carbonate precipitation isolated from atmospheric CO2. Mass balance calculations indicate that the weathering of Ca-bearing peridotite silicates such as diopside is a feasible source of Ca in Ronda Ca-OH hyperalkaline fluids; however, it requires steady-state dissolution rates substantially greater than those determined experimentally. Travertine, crystalline crusts and sediment deposits are the main types of solid precipitates observed in Ronda hyperalkaline spring sites. Calcite and aragonite, minor dolomite and Mg-Al-rich clays are the main minerals in the spring sites. As illustrated in the Baños del Puerto spring site, (i) calcite-dominated precipitation is due to hyperalkaline fluid uptake of atmospheric CO2 during discharge, and (ii) aragonite-dominated precipitation is due to mixing of Ca-OH hyperalkaline fluids with Mg- HCO3 river waters. Aragonite and dolomite contents increase away from the springs and toward the river waters that uniquely reflects the effect of Mg ions on the precipitation of aragonite versus calcite. Other potential factors controlling the precipitation of these CaCO3 polymorphs are the Mg/Ca ratio, the CO2 content, and the temperature of the fluids. Dolomite forms during lithification of travertine due to periodic flooding of river water combined with subsequent evaporation.
DS201809-2107
2018
Vadlamani, R.Vadlamani, R., Bera, M.K., Samata, A., Mukherjee, S., Adhikari, A., Sarkar, A.Oxygen, Sr and Nd isotopic evidence from kyanite eclogite xenoliths ( KL-2 pipe, Wajrakarur) for pre 1.1 Ga mantle metasomatism in eastern Dharwar SCLM.Goldschmidt Conference, 1p. AbstractIndiadeposit - KL-2

Abstract: Kyanite-eclogite xenoliths from Wajrakarur are considered as remnants of subducted ocean-floor crust. Here trace element concentration and isotopic data are presented in garnet (Grt) and kyanite (Ky) from xenoliths KL-2 E1-E4, characterized by. We use the precise 87Sr/86Sr host kimberlite groundmass perovskite ratio (0.70312-0.70333, as a proxy for the extent of kimberlitic magma infiltration at 1.1 Ga. The xenolithic Grt and Cr-rich (upto 1506 ppm) Ky have more radiogenic 87Sr/86Sr values than kimberlite, at 1.1 Ga, of 0.703829-0.705203 and 0.703811-0.704502, respectively. Furthermore, the Grt and Ky 143Nd/144Nd ratios, at 1.1 Ga, are 0.509321-0.511372 and 0.510951-0.511156, respectively, and are distinctly lower than those of the host kimberlite (0.511870-0.512290). This indicates that the infiltration of kimberlitic fluid has not altered the 87Sr/86Sr and 143Nd/144Nd ratios in the Grt and Ky, and therefore their isotope compositions must be inherited and predate the kimberlite magma generation event at 1.1 Ga. Trace elements in Grt and Ky indicate extreme metasomatism (Sr in Grt 104-296 ppm, in Ky 672-8713 ppm [limit Sr<2ppm] and Nb in Grt 0.64-1.78 ppm, in Ky 1.7-4.54 ppm [limit Nb<0.5ppm]). The xenoliths underwent at least one major melting event inferred from extreme depletions in Re, Os and 177Os/178Os ratios [5]. Their mantle-like ?18O values (Grt 5.3-5.4‰, Ky 5.3-5.9‰), positive Eu anomalies in both Grt and Ky (similar to Group 1 HREE-depleted garnets of) suggests that the protolith likely was a chromite-bearing leucogabbro, emplaced as a high-pressure cumulate at the crust-mantle boundary, which was later eclogitized due to deep-seated subduction and underwent episodes of extreme melting and metasomatism before 1.1 Ga and at least before 1.7 Ga, as inferred from their youngest Re depletion dates.
DS201909-2100
2019
Vadlamani, R.Vadlamani, R., Bera, M.K., Samanta, A., Mukherjee, S., Adhikari, A., Sarkar, A.Oxygen, Sr and Nd isotopic evidence from kyanite-eclogite xenoliths ( KL-2 pipe, Wajrakarur) for pre- 1.1 Ga mantle metasomatism in eastern Dharwar SCLM.Goldschmidt2019, 1p. AbstractIndiadeposit - KL-2

Abstract: Kyanite-eclogite xenoliths from Wajrakarur are considered as remnants of subducted ocean-floor crust [1]. Here trace element concentration and isotopic data are presented in garnet (Grt) and kyanite (Ky) from xenoliths KL-2 E1-E4, characterized by [2]). We use the precise 87Sr/86Sr host kimberlite groundmass perovskite ratio (0.70312-0.70333, [3]) as a proxy for the extent of kimberlitic magma infiltration at 1.1 Ga. The xenolithic Grt and Cr-rich (upto 1506 ppm) Ky have more radiogenic 87Sr/86Sr values than kimberlite, at 1.1 Ga, of 0.703829-0.705203 and 0.703811-0.704502, respectively. Furthermore, the Grt and Ky 143Nd/144Nd ratios, at 1.1 Ga, are 0.509321-0.511372 and 0.510951-0.511156, respectively, and are distinctly lower than those of the host kimberlite (0.511870-0.512290, [4]). This indicates that the infiltration of kimberlitic fluid has not altered the 87Sr/86Sr and 143Nd/144Nd ratios in the Grt and Ky, and therefore their isotope compositions must be inherited and predate the kimberlite magma generation event at 1.1 Ga. Trace elements in Grt and Ky indicate extreme metasomatism (Sr in Grt 104-296 ppm, in Ky 672-8713 ppm [limit Sr<2ppm] and Nb in Grt 0.64-1.78 ppm, in Ky 1.7-4.54 ppm [limit Nb<0.5ppm]). The xenoliths underwent at least one major melting event inferred from extreme depletions in Re, Os and 177Os/178Os ratios [5]. Their mantle-like ?18O values (Grt 5.3-5.4‰, Ky 5.3-5.9‰), positive Eu anomalies in both Grt and Ky (similar to Group 1 HREE-depleted garnets of [1]) suggests that the protolith likely was a chromite-bearing leucogabbro, emplaced as a high-pressure cumulate at the crust-mantle boundary, which was later eclogitized due to deep-seated subduction and underwent episodes of extreme melting and metasomatism before 1.1 Ga and at least before 1.7 Ga, as inferred from their youngest Re depletion dates [5].
DS1986-0657
1986
Vagahov, V.I.Prokopchuk, B.I., Vagahov, V.I.From uncut diamonds to cut diamonds.(Russian)Nedra Moscow, (Russian), 126pRussiaDiamond cutting
DS1975-0303
1976
Vaganov, V.I.Kaminskiy, F.V., Vaganov, V.I.Petrologic Reasons for Possible Diamond Occurrence in Alpine Type Ultramafics.Izvestiya Akad. Nauk Sssr, Geol. Ser., 1976, No. 06, PP. 35-47.RussiaPetrology, Diamond Genesis
DS1980-0280
1980
Vaganov, V.I.Perchuk, L.L., Vaganov, V.I.Petrochemical and Thermodynamic Evidence on the Origin of Kimberlites.Contributions to Mineralogy and Petrology, Vol. 72, PP. 219-228.South AfricaKimberlite Genesis
DS1983-0612
1983
Vaganov, V.I.Vaganov, V.I., Varlamov, V.A.Structural position and conditions of formation of Kimberlites in Siberian and American platforms. (Russian)Soviet Geology, (Russian), No. 3, pp. 86-89RussiaGeotectonics
DS1983-0613
1983
Vaganov, V.I.Vaganov, V.I., Varlamov, V.A.Structural Position and Condition of Formation of Kimberlites in the Siberian and African Platforms.Soviet Geology, No. 3, PP. 86-89.Russia, South Africa, AfricaTectonics, Structure, Genesis
DS1992-1405
1992
Vaganov, V.I.Simakov, S.K., Vaganov, V.I.New petrological criteria for preliminary estimation of diamond content of deep mantle rocks.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 323, No. 3, pp. 531-534.RussiaKimberlites, Petrology
DS1995-1949
1995
Vaganov, V.I.Vaganov, V.I.Petrological features of Diamondiferous magmatismProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 648.Australia, ArkansasPetrology, Kimberlite magmatism
DS1995-1950
1995
Vaganov, V.I.Vaganov, V.I., Golubev, Y.K., et al.Mineralogical indicators of presence of alkali ultrapotassic potentially diamondiferous Mesozoic...Doklady Academy of Sciences Nauk. (Russian), Vol. 341, No. 3, March pp. 373-376.RussiaEast European Platform, Ultrapotassics
DS1995-1951
1995
Vaganov, V.I.Vaganov, V.I., Varlamov, V.A., Feldman, A.A., et al.Diamondiferous magmatism: miner agenetic taxons and prediction prospectingmethods.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 649.RussiaMineralogy, Prospecting
DS1996-1455
1996
Vaganov, V.I.Vaganov, V.I., et al.Mineralogical indicators for the presence of Mesozoic alkali-ultrabasic potentially diamond bearing rocks...Doklady Academy of Sciences, Vol. 344 No. 7, August pp. 42-46.Russia, East EuropeanEast European Platform, Mineralogy
DS1994-1987
1994
Vagarali, S.S.Zhang, S.G., Zvanut, M.E., Vohra, Y.K., Vagarali, S.S.Nitrogen in the isotopically enriched C-12 diamondAppl. Phys. Letters, Vol. 65, No. 23, Dec. 5, pp. 2951-2957.GlobalDiamond morphology, Nitrogen
DS200912-0478
2009
Vaidya, A.Masun, K., Sthapak, A.V., Singh, A., Vaidya, A., Krishna, C.Exploration history and geology of the Diamondiferous ultramafic Saptarshi intrusions, Madhya Pradesh, India.Lithos, In press available, 37p.IndiaBunder project area
DS1975-0644
1977
Vaidyanadhan, R.Vaidyanadhan, R.Recent Advances in Geomorphic Studies of Peninsular India: A Review.India Journal of Earth Sciences, S. Roy Volume., PP. 13-35.IndiaGeomorphology
DS1950-0434
1958
Vail, J.R.Vail, J.R.The Dembe Divula Complex (the Nuanetsi Igneous Complex)Leeds University Research Institute of African Geology Annual Report, APP. C, Vol. 1C, PP. 7-8.Tanzania, East AfricaGeology, Tectonics
DS1950-0510
1959
Vail, J.R.Vail, J.R.The Dembe Divula Complex ( the Nuanetsi Igneous Axis)Leeds University Research Institute of African Geology Annual Report, APP. C, Vol. 4B, PP. 27-29.Tanzania, East AfricaGeology, Tectonics
DS1960-0028
1960
Vail, J.R.Cox, K.G., Johnson, R.L., Monkman, L.J., Vail, J.R.Progress of Investigations in Southeast Southern RhodesiaLeeds University Research Institute of African Geology Annual Report, APP. C, Vol. 4, PP. 26-28.ZimbabweGeology, Related Rocks
DS1960-0103
1960
Vail, J.R.Vail, J.R.Geology of the Late Karroo Granitic Complex of the Dembe Divula Mateke Hills Nuanetsi District, Southern Rhodesia.Leeds: Ph.d. Thesis, University Leeds, ZimbabweRegional Studies
DS1960-0135
1961
Vail, J.R.Cox, K.G., Vail, J.R., Monkman, L.J., Johnson, R.L.Karroo Igneous Activity and Tectonics in Southeast Southern Rhodesia.Nature., Vol. 190, No. 4770, P. 40.; P. 77.ZimbabweGeology, Related Rocks, Tectonics
DS1960-0306
1962
Vail, J.R.Vail, J.R.Late Karroo Intrusion Breccias from the Nuanetsi District Of Southern Rhodesia, with Special Reference to the Granitic Complex of Dembe Divula.Geological Society of South Africa Transactions, Vol. 65, No. 2, PP. 139-152.ZimbabweGeology, Related Rocks
DS1960-0504
1964
Vail, J.R.Vail, J.R.Mesozoic Igneous Activity in Central AfricaInternational Geological Congress 22ND., (NEW DELHI), PP. 245-246.Central AfricaGeology
DS1960-0505
1964
Vail, J.R.Vail, J.R.Summary of Results of Geochronological InvestigationsLeeds University Research Institute of African Geology Annual Report 8th., Vol. 5A, PP. 50-52.South Africa, Central AfricaGeochronology
DS1960-0506
1964
Vail, J.R.Vail, J.R.Mesozoic Igneous Rocks in Southern Africa, and the Dating Of the Magmatic Activity.Leeds University Research Institute of African Geology Annual Report 8th., Vol. 3A, PP. 27-29.South Africa, Central AfricaGeochronology, Geology
DS1960-0754
1966
Vail, J.R.Vail, J.R.Dembe-divula a Late Karroo Granite Gabbro Ring Complex in The Nuanetsi Igneous Province of Southern Rhodesia.Geological Society of South Africa Transactions, Vol. 69, PP. 71-85.ZimbabweGeology, Related Rocks
DS1960-0890
1967
Vail, J.R.Vail, J.R.Distribution of Non-orogenic Igneous Complexes in Southern Rhodesia and Their Tectonic Setting.Leeds University Research Institute of African Geology Annual Report, Vol. 2C, PP. 33-35.ZimbabweRelated Rocks, Tectonics
DS1984-0179
1984
Vail, J.R.Cahen, L., Snelling, N.J., Delhal, J., Vail, J.R.The Geochronology and Evolution of AfricaOxford Clarendon Press, 512P.Africa, South Africa, West Africa, Central Africa, East AfricaKimberley, Tectonics, Structure, Regional Geology
DS1989-1534
1989
Vail, J.R.Vail, J.R.Ring complexes and related rocks in AfricaJournal of African Earth Sciences, Vol. 8, No. 1, pp. 19-40AfricaTectonics, Ring complexes
DS1998-0091
1998
Vail, P.R.Baum, G.R., Vail, P.R.A new foundation for stratigraphy...... sequence model and geophysicsGeotimes, Vol. 43, No. 11, Nov. pp. 31-35.MantleStratigraphy, General - brief history ( not specific to diamonds)
DS202107-1134
2021
Vaillancourt, A.Snyder, D.B., Savard, G., Kjarssgaard, B.A., Vaillancourt, A., Thurston, P.C., Ayer, J.A., Roots, E.Multidisciplinary modeiling of mantle lithosphere structure within the Superior craton, North America.Geochemistry, Geophysics, Geosytems, 20p. PdfCanada, United Statesgeophysics - seismics

Abstract: Structure within the Earth is best studied in three dimensions and using several coincident overlays of diverse information with which one can best see where unusual properties match up. Here we use regional surfaces causing discontinuities in seismic waves a few hundred kilometers deep in the Earth, intersected and thus calibrated by rebuilt rock columns using rare rock samples erupted to the surface in two locations. Electrically conductive regions can be mapped using natural (magnetotelluric) currents. East- and west-dipping seismic discontinuity surfaces match surface structures that developed about 1.8 billion years ago marginal to the Superior crustal block. Surfaces dipping to the southeast and northwest match some boundaries between crustal blocks that are over 2.5 billion years old, but many such crustal boundaries trend more east-west. Conductive rocks appear more commonly above these discontinuity surfaces where gas-rich fluids apparently flowed and that the discontinuities somehow filtered these fluids. The mismatch in orientation and dip between the most ancient deep and exposed structures suggests that plate tectonic processes operating today differed earlier than 2.5 billion years ago.
DS200412-0331
2004
Vaillancourt, C.Ciesielski, A., Marchand, J., Vaillancourt, C.Volcanic hosted diamonds from northern Ontario: a non-kimberlitic origin.Geological Association of Canada Abstract Volume, May 12-14, SS14P02, p. 274.abstractCanada, OntarioVolcaniclastic breccias
DS200512-1113
2004
Vaillancourt, C.Vaillancourt, C., Ayer, J.A., Zubowski, S.M., Kamo, S.L.Synthesis and timing of Archean geology and diamond bearing rocks in the Michipicotem greenstone belt: Menzies and Musquash Townships.Ontario Geological Survey Report of Activities 2004, No. 6, pp. 6-1-6-8.Canada, OntarioLamprophyre, Moet, Festival Pele Mountain
DS200612-1457
2005
Vaillancourt, C.Vaillancourt, C., Ayer, J.A., Hamilton, M.A.Project 03-002. Synthesis of Archean geology and diamond bearing rocks in the Michipicoten Greenstone Belt: results from microdiamond extraction and geochronology.Ontario Geological Survey Summary of Fieldwork 2005, O.F. 6172, pp. 8-1-13.Canada, Ontario, WawaGeochronology, geochemsirty
DS2003-1403
2003
Vaillencourt, C.Vaillencourt, C., Wilson, A.C., Dessureau, G.R.Synthesis of Archean geology and diamond bearing rocks in the MichipicotenOntario Geological Survey Open File, No. 6120, pp. 9 1-11.Ontario, WawaPetrology - Band-Ore, Pele, Dia Bras, Spider, Oasis, Du
DS200412-2030
2003
Vaillencourt, C.Vaillencourt, C., Wilson, A.C., Dessureau, G.R.Synthesis of Archean geology and diamond bearing rocks in the Michipicoten greenstone belt, Geology of Menzies Township.Ontario Geological Survey Open File, No. 6120, pp. 9 1-11.Canada, Ontario, WawaPetrology - Band-Ore, Pele, Dia Bras, Spider, Oasis, Du
DS202011-2065
2020
Vainer, S.Vainer, S., Matmon, A., Erel, A.J., Hidy, A.J., Crouvi, O., De Wit, M., Geller, Y.Landscape responses to intraplate deformation in the Kalahari constrained by sediment provenance and chronology in the Okavango Basin.Basin Research, in press available Africa, South Africageomorphology

Abstract: The structural depression that occupies the Okavango Basin in southern Africa comprises a depo?centre within the intracratonic Kalahari Basin where sediments of the Cenozoic Kalahari Group have accumulated. The Okavango Basin has been formed due to stretching and subsidence at an area of diffused deformation, southwestwards to the main East African Rift System (EARS). Sediments from two full Kalahari Group sequences, located on opposite sides of the Gumare Fault that forms a major fault within the Okavango Basin, were studied to determine their provenance and chronology. Terrestrial Cosmogenic Nuclide (TCN) 26Al/10Be burial dating was used to constrain a chronostratigraphical framework, and Pb, Sr, and Nd isotopic ratios combined with geochemical and sedimentological analyses were applied to track the source areas of the sediments.Results indicate the following sequence of basin filling: (a) Accumulation between ca. 4-3 Ma during which the currently downthrown (southern) block received a mixture of sediments mostly from the Choma?Kalomo, Ghanzi?Chobe, and Damara terranes, and possibly from the Lufilian Belt and/or Karoo basalts during earlier stages of deposition. Simultaneously, the upthrown (northern) block received sediments from more distant Archean sources in the Zimbabwe and/or Kasai cratons, (b) Hiatus in sedimentation occurred at both sites between ca. 3-2 Ma, (c) Sediments on both sides of the Gumare Fault share a similar source (Angolan Shield) with minor distinct contributions to the downthrown block from the Kasai Craton and local sources input to the upthrown block, and (d) Regional distribution of aeolian sand since at least 1 Ma. The change in source areas is attributed to rearrangements of the drainage systems that were probably linked to vertical crustal movements on the margins of the Okavango Basin. The tectonically induced morphodynamics controlled the landscape evolution of the endorheic basin where vast lakes, wetlands and salt pans have developed through time.
DS2000-0970
2000
Vaisanen, M.Vaisanen, M., Mantarri, I., Kriegsman, L.M., Holtta, P.Tectonic setting of post collisional magmatism in the Paleoproterozoic Svecofennian Orogen, southwest Finland.Lithos, Vol. 54, No. 1-2, Oct. pp. 63-81.FinlandTectonics, mantle enrichment, magmatism
DS2002-1628
2002
Vaisanen, M.Vaisanen, M., Manttari, I., Holtta, P.Svecofennian magmatic and metamorphic evolution in southwestern FIn land as revealed by U Pb zircon SIMS geochronology.Precambrian Research, Vol. 116, No.1-2, pp. 111-27.FinlandMagmatism, Geochronology
DS202008-1405
2020
Vaisanen, M.Kara, J., Vaisanen, M., Heinonen, J.S., Lahaye, Y., O'Brien, H., Huhma, H.Tracing arcologites in the Paleoproteroic era - a shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian shield.Lithos, in press available, 68p. PdfEurope, Fennoscandiaalkaline
DS200612-0757
2005
Vaittinen, K.Lahti, I., Korja, T., Kaikkonen, P., Vaittinen, K.Decomposition analysis of the BEAR magnetotelluric data: implications for the upper mantle conductivity in the Fennoscandian Shield.Geophysical Journal International, Vol. 163, 3, Dec. pp. 900-914.Europe, Fennoscandia, Finland, SwedenGeophysics - magnetotelluric
DS201212-0742
2012
Vaittinen, K.Vaittinen, K., Korja, T., Kaikkonen, P., Lahti, I., Smirnov, M.Yu.High resolution magnetotelluric studies of the Archean Proterozoic border zone in the Fennoscandian shield, FinlandGeophysical Journal International, inpress availableEurope, FinlandGeophysics, magetics
DS200912-0752
2009
Vajda, P.Tenzer, R., Hamayun, K., Vajda, P.Global maps of the CRUST 2.0 crustal components stripped gravity disturbances.Journal of Geophysical Research, Vol. 114, B05408.MantleGeophysics - discontinuity
DS202009-1671
2020
Vakeva, S.Tiira, T., Janik, T., Skrzynik, T., Komminaho, K., Heinonen, A., Veikkolainen, T., Vakeva, S., Korja, A.Full scale crustal interpretation of Kokkola-Kymi ( KOKKY) seismic profile, Fennoscandian shield.Pure and Applied Geophysics, Vol. 177, 8, pp. 3775-3795. pdfEurope, Finlandgeophysics - seismics

Abstract: The Kokkola-Kymi Deep Seismic Sounding profile crosses the Fennoscandian Shield in northwest-southeast (NW-SE) direction from Bothnian belt to Wiborg rapakivi batholith through Central Finland granitoid complex (CFGC). The 490-km refraction seismic line is perpendicular to the orogenic strike in Central Finland and entirely based on data from quarry blasts and road construction sites in years 2012 and 2013. The campaign resulted in 63 usable seismic record sections. The average perpendicular distance between these and the profile was 14 km. Tomographic velocity models were computed with JIVE3D program. The velocity fields of the tomographic models were used as starting points in the ray tracing modelling. Based on collected seismic sections a layer-cake model was prepared with the ray tracing package SEIS83. Along the profile, upper crust has an average thickness of 22 km average, and P-wave velocities (Vp) of 5.9-6.2 km/s near the surface, increasing downward to 6.25-6.40 km/s. The thickness of middle crust is 14 km below CFGC, 20 km in SE and 25 km in NW, but Vp ranges from 6.6 to 6.9 km/s in all parts. Lower crust has Vp values of 7.35-7.4 km/s and lithospheric mantle 8.2-8.25 km/s. Moho depth is 54 km in NW part, 63 km in the middle and 43 km in SW, yet a 55-km long section in the middle does not reveal an obvious Moho reflection. S-wave velocities vary from 3.4 km/s near the surface to 4.85 km/s in upper mantle, consistently with P-wave velocity variations. Results confirm the previously assumed high-velocity lower crust and depression of Moho in central Finland.
DS1960-0878
1967
Vakhrushev, V.A.Sobolev, N.V., Vakhrushev, V.A.Sulfides in Pyrope Peridotites in Kimberlites from YakutiaZap. Vses. Miner. Obshch., PT. 96, No. 4, P. 450.RussiaBlank
DS1970-0439
1971
Vakhrushev, V.A.Vakhrushev, V.A., Sobolev, N.V.Sulfidic Formations in Deep Xenoliths from Kimberlites in Yakutia.International Geology Review, Vol. 15, No. 1, PP. 103-110.RussiaBlank
DS1989-1535
1989
Vakil, H.B.Vakil, H.B., Banholze.., W.F., Kehl, R.J.An experimental investigation of the isotope effect in the CVD growth ofdiamondsMater. Res. Bulletin, Vol. 24, No. 6, June pp. 733-738GlobalCVD Diamond morphology, Diamond synthetic
DS200612-0376
2006
Vaksman, V.L.Eppelbaum, L.V., Vaksman, V.L., Kuznetsov, Sazonova, Smirnov, Surkov, Bezlepkin, Katz, Lorotaeva, BelovitDiscovery of microdiamonds and associated minerals in the Makhtesh Ramon Canyon (Negrev Desert) Israel.Doklady Earth Sciences, Vol. 407, 2, Feb-Mar. pp. 202-204.Europe, IsraelMicrodiamonds
DS201703-0401
2016
Vaksman, V.L.Eppelbaum, L.V., Vaksman, V.L.Makhtesh Ramon Complex deposit ( southern Israel) - a window to the upper mantle.International Journal of Mining Science, Vol. 3, 1, pp. 1-28.Europe, IsraelKimberlite, Lamproite

Abstract: An integrated analysis of several regional geological and geophysical factors allowed to select the Makhtesh Ramon area (northern Negev, Israel) for sesarching diamondiferous associations. The most important regional factor is the Middle Cretaceous maximum in the development of upper mantle hot spots brightly appearing in this area. Analysis of magnetic (paleomagnetic), self-potential and ionselective data inambogously indicate presence of some bodies possibly having kimberlite (lamproite) origin occurring at small depths (8 - 50 m) in the western Makhtesh Ramon. Repeated erosion processes in the area caused removing most part of sedimentary associations that significantly simplified the processes of mineral sampling and rock withdrawn for geochemical and petrological analyses. Comprehensive mineralogical analyses enabled to detect the following minerals-satellites of diamond associations: chrome-diopside, orange garnet, bright-crimson pyrope, picroilmenite, moissanite, corundum, black spinel, olivine, anatase and tourmaline (including black samples). These minerals do not rolled and oxidized that is an additional evidence of the neighboring occurrence of the indigenous rocks. Data of electronic microscopy show that the grains of (1) picroilmenite and (2) pyrope contain, respectively: (1) cobalt, chrome, magnesium and nickel and (2) chrome, magnesium and aluminum. This indicates that both picroilmenite and pyrope have the hyper-abyssal origin that also is an indicator of the possible occurring of diamondiferous pipes. List of secondary-importance satellite minerals includes feldspars, pyroxenes, magnetite, hematite, ilmenite, galenite, pyrite, limonite, mica, chromite, leucoxene, zircon, rutile, etc. These minerals (by their considering with the first group) are also indicators of diamond-bearing of the studied area. Identification of small plates of gold and silver as well as considerable traces of La, Ce, Th, Nb and Ta (Rare Earth Elements) also may be associated with the nearest kimberlite rock occurrence. The total number of recognized microdiamonds consists of more than 300 units; five diamonds (> 1 mm) were identified (sizes of the most largest crystals are 1.2 and 1.35 mm). Thus, on the basis of a set of geological-geophysical factors and identification of the mentioned minerals we can definitely estimate that the Makhtesh Ramon area is perspective for discovering diamondiferous rocks (kimberlite or lamproite pipes) as well as diamond crystals in loose deposits. Discovered silver- and gold-bearing and REE signatures may have independent importance.
DS1960-0614
1965
Valachi, L.Y.Valachi, L.Y., Kopp, O.C.Petrographic Study of the Norris Peridotite, Union County, Tennessee.Geological Society of America (GSA) SPECIAL PAPER., No. 82, PP. 310-311.Appalachia, TennesseePetrography
DS201212-0019
2012
Valadao, L.V.Araujo, D.P., Weska, R.K., Correa, R.S., Valadao, L.V., Kuberek, N.T., Suvorova, L.F.The kimberlite Juina-5 Brazil: textural and xenocryst chemistry.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Juina-5
DS2001-0830
2001
Valarelli, J.V.Neumann, R., Valarelli, J.V.Technological characterization of the potential RE ores from Corrego do Garimpo, Catalao, Central Brasil.Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 27. (abs)Brazil, CentralCarbonatite, Corrego do Garimpo
DS201609-1752
2010
Valbom, D.M.C.Valbom, D.M.C., Dellas, G.State of the art recovery plant design.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 10p.TechnologySorting

Abstract: The introduction of new diamond sorting technologies as well as additional manufacturers I vendors, has increased the equipment selection and combinations available for recovery flowsheet design. This paper describes the methodology used and the benefits realized in the design of recovery plants by ensuring a fundamental understanding of the advantages and limitations of the technology embodied in the equipment, a comprehensive knowledge of the ore body characteristics, and the effective matching of this information in combination with operational commercial requirements.
DS1996-1456
1996
Valbracht, P.J.Valbracht, P.J., Honda, M., Weis, D.Helium, neon and argon isotope systematics in Kerguelen ultramaficxenoliths:mantle source signaturesEarth and Planetary Science Letters, Vol. 138, No. 1/4, Feb. 1, pp. 29-38.MantleGeochronology, Xenoliths
DS1997-1185
1997
Valdespino, O.E.M.Valdespino, O.E.M., Alvarez, V.C.Paleomagnetic and rock magnetic evidence for inverse zoning in the Parquazabatholith, tectonics of shieldPrecambrian Research, Vol. 85, No. 1-2, Nov. 1, pp. 1-26Venezuela, GuyanaTectonics, Paleomagnetism
DS1997-1186
1997
Valdespino, O.E.M.Valdespino, O.E.M., Costanzo Alvarez, V.Paleomagnetic and rock magnetic evidence for inverse zoning in the Parguazabatholith and tectonics of...Precambrian Research, Vol. 85, 1-2, Nov. 1, pp. 1-26.Venezuela, GuyanaTectonics, Geophysics - magnetics
DS201012-0613
2010
Valdeswaran, T.Ravi, S., Patel, S.C., Bhaskara Rao, K.S., Valdeswaran, T.Geology of the Chagapuram pyroclastic kimberlites near Kurnool Basin, southern India.International Dyke Conference Held Feb. 6, India, 1p. AbstractIndiaDeposit - Chagapuram arena
DS201212-0743
2012
Valdez, M.N.Valdez, M.N., Wu, Z., Yu, Y.G., Revenaugh,J., Wentzcovitch, R.M.Thermoeleastic properties of ringwoodite: its relationship to the 520 seismic discontinuity.Earth and Planetary Science Letters, Vol. 351-352, pp. 115-122.MantleGeophysics - seismics
DS201812-2895
2018
Valdir da Silveira, F.Valdir da Silveira, F.Overview of diamonds in Brazil.7th Symposio Brasileiro de Geologia do Diamante , Title only South America, Brazildiamond occurrence
DS201812-2896
2018
Valdir da Silveira, F.Valdir da Silveira, F.Project diamond Brazil.7th Symposio Brasileiro de Geologia do Diamante , Title only South America, Brazilprospecting
DS201112-0904
2010
Valdir Silveira, F.Sander, A., Provenzano, C., Valdir Silveira, F., Castro, J.H., Bottari, L.Um novo corpo kimberlitico no escudo sul rio Grandense: petrografia preliminar.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 75.South America, BrazilGeobank
DS1996-1457
1996
Valdivia, F.J.Valdivia, F.J.Simplifying cartographic boundaries by using a normalized measure ofambiguityComputers and Geosciences, Vol. 22, No. 6, pp. 607-624GlobalComputers, Cartographic boundaries
DS1960-1047
1968
Valdovinos, D.L.Valdovinos, D.L.Petrography of Some Lamprophyres of the Eastern Ouachita Mountains of Arkansaw.Msc. Thesis, University Arkansaw, 146P.United States, Oklahoma, ArkansasPetrology
DS2001-0563
2001
Vale, E.Kahn, J.R., Francheschi, D., Curi, A., Vale, E.Economic and financial aspects of mine closureNatural Res. Forum, Vol. 25, No. 4, pp. 265-74.GlobalLegal - economics, Mine closure
DS1980-0333
1980
Valenca, J.G.Valenca, J.G.Geology, Petrography and Petrogenesis of Some Alkaline Igneounited States Complexes of Rio de Janeiro State, Brasil.Ph.d. Thesis, University Western Ontario, BrazilCarbonatite, Leucite, Petrology, Kimberley
DS1991-1547
1991
Valenca, J.G.Sgarbi, P.B.A., Valenca, J.G.Petrography and general features of potassic mafic to ultramafic alkaline volcanic rocks of Mat a da Corda Formation, Minas Gerais State, BrasilProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 359-360BrazilKamafugitic lavas, Patos
DS1994-1572
1994
Valenca, J.G.Sgarbi, P.B.A., Valenca, J.G.Mineral and rock chemistry of the Mat a da Corda kamafugitic rocks Minas gerais State.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 27-29.BrazilGeochemistry, Kamafugites
DS200912-0784
2009
Valencia, D.Valencia, D., O'Connell, R.J.Convection scaling and subduction on Earth and super-Earths.Earth and Planetary Science Letters, Vol. 286, 3-4, pp. 492-502.MantleConvection
DS200512-0249
2005
Valencia, V.A.Ducea, M.N., Saleeby, J., Morrison, J., Valencia, V.A.Subducted carbonates, metasomatism of mantle wedges, and possible connections to diamond formation: an example from California.American Mineralogist, Vol. 90, pp. 864-870.United States, CaliforniaSierra Nevada mantle, peridotites
DS202101-0015
2020
Valencia-Cardona, J.Houser, C., Hernlund, J.W., Valencia-Cardona, J., Wentzcovitch, R.M.Discriminating lower mantle composition.Physics of the Earth and Planetary Interiors, Vol. 308, 106552, 14p. PdfMantlegeophysics - seismics

Abstract: Constraining Earth's bulk composition is fundamental to understanding our planet's formation and evolution. While the lower mantle accounts for a majority of the bulk silicate Earth, it is also the least accessible. As experimental and theoretical mineral physics constraints on mineral elasticity at lower mantle temperatures and pressures have improved, comparisons between predicted seismic velocity and density profiles for hypothesized bulk compositions and 1D seismic models have become commonplace. However, the degree to which a given composition is a better or worse fit than another composition is not always reported, nor are the influences of the assumed temperature profile and other uncertainties discussed. Here we compare seismic velocities and densities for perovskitite, pyrolite, and harzburgite bulk compositions calculated using advanced ab initio techniques to explore the extent to which the associated uncertainties affect our ability to distinguish between candidate compositions. We find that predicted differences between model compositions are often smaller than the influence of temperature uncertainties and therefore these comparisons lack discriminatory power. The inability to distinguish between compositions is largely due to the high sensitivity of seismic properties to temperature accompanied by uncertainties in the mantle geotherm, coupled with diminished sensitivity of seismic velocity to composition toward the base of the mantle. An important exception is the spin transition in (Mg,Fe)O-ferropericlase, which is predicted to give a distinct variation in compressional wave velocity that should distinguish between relatively ferro-magnesian and silica-rich compositions. However, the absence of an apparent spin transition signature in global 1D seismic profiles is a significant unresolved issue in geophysics, and it has important geochemical implications. The approach we present here for establishing discriminatory power for such comparisons can be applied to any estimate of seismic velocities and associated uncertainties, and offers a straightforward tool to evaluate the robustness of model comparisons.
DS202102-0199
2021
Valencia-Cardona, J.Houser, C., Hernlund, J.W., Valencia-Cardona, J., Wentzcovitch, R.M.Discriminating lower mantle composition.Physics of the Earth and Planetary Interiors, Vol. 308, di.org/10.1016 /jpepi.2020. 106552 14p. PdfMantlegeophysics - seismics

Abstract: Constraining Earth's bulk composition is fundamental to understanding our planet's formation and evolution. While the lower mantle accounts for a majority of the bulk silicate Earth, it is also the least accessible. As experimental and theoretical mineral physics constraints on mineral elasticity at lower mantle temperatures and pressures have improved, comparisons between predicted seismic velocity and density profiles for hypothesized bulk compositions and 1D seismic models have become commonplace. However, the degree to which a given composition is a better or worse fit than another composition is not always reported, nor are the influences of the assumed temperature profile and other uncertainties discussed. Here we compare seismic velocities and densities for perovskitite, pyrolite, and harzburgite bulk compositions calculated using advanced ab initio techniques to explore the extent to which the associated uncertainties affect our ability to distinguish between candidate compositions. We find that predicted differences between model compositions are often smaller than the influence of temperature uncertainties and therefore these comparisons lack discriminatory power. The inability to distinguish between compositions is largely due to the high sensitivity of seismic properties to temperature accompanied by uncertainties in the mantle geotherm, coupled with diminished sensitivity of seismic velocity to composition toward the base of the mantle. An important exception is the spin transition in (Mg,Fe)O-ferropericlase, which is predicted to give a distinct variation in compressional wave velocity that should distinguish between relatively ferro-magnesian and silica-rich compositions. However, the absence of an apparent spin transition signature in global 1D seismic profiles is a significant unresolved issue in geophysics, and it has important geochemical implications. The approach we present here for establishing discriminatory power for such comparisons can be applied to any estimate of seismic velocities and associated uncertainties, and offers a straightforward tool to evaluate the robustness of model comparisons.
DS202111-1784
2021
Valencia-Cardona, J.J.Shephard, G.E., Houser, C., Hernlund, J.W., Valencia-Cardona, J.J., Tronnes, R.G., Wentzcovitch, R.M.Seismological expression of the iron spin crossover in ferropericlase in the Earth's lower mantle.Nature Communications, Vol. 12, 1, doi:10.1038/s41467-021-26115-zMantlegeophysics - seismics

Abstract: The two most abundant minerals in the Earth’s lower mantle are bridgmanite and ferropericlase. The bulk modulus of ferropericlase (Fp) softens as iron d-electrons transition from a high-spin to low-spin state, affecting the seismic compressional velocity but not the shear velocity. Here, we identify a seismological expression of the iron spin crossover in fast regions associated with cold Fp-rich subducted oceanic lithosphere: the relative abundance of fast velocities in P- and S-wave tomography models diverges in the?~1,400-2,000 km depth range. This is consistent with a reduced temperature sensitivity of P-waves throughout the iron spin crossover. A similar signal is also found in seismically slow regions below?~1,800 km, consistent with broadening and deepening of the crossover at higher temperatures. The corresponding inflection in P-wave velocity is not yet observed in 1-D seismic profiles, suggesting that the lower mantle is composed of non-uniformly distributed thermochemical heterogeneities which dampen the global signature of the Fp spin crossover.
DS202202-0216
2021
Valencia-Cardona, J.J.Shephard, G.E., Houser, C., Hernlund, J.W., Valencia-Cardona, J.J., Tronnes, R.G., Wentzcovitch, R.M.Seismological expression of the iron spin crossover in ferropericlase in the Earth's lower mantle.Nature Communications, Vol. 12 5905 10.1038/s41467-021-26115-zMantletomography

Abstract: The two most abundant minerals in the Earth’s lower mantle are bridgmanite and ferropericlase. The bulk modulus of ferropericlase (Fp) softens as iron d-electrons transition from a high-spin to low-spin state, affecting the seismic compressional velocity but not the shear velocity. Here, we identify a seismological expression of the iron spin crossover in fast regions associated with cold Fp-rich subducted oceanic lithosphere: the relative abundance of fast velocities in P- and S-wave tomography models diverges in the?~1,400-2,000 km depth range. This is consistent with a reduced temperature sensitivity of P-waves throughout the iron spin crossover. A similar signal is also found in seismically slow regions below?~1,800 km, consistent with broadening and deepening of the crossover at higher temperatures. The corresponding inflection in P-wave velocity is not yet observed in 1-D seismic profiles, suggesting that the lower mantle is composed of non-uniformly distributed thermochemical heterogeneities which dampen the global signature of the Fp spin crossover.
DS201012-0808
2010
Valente, S.Valente, S.The petrogenesis of alkaline and ultramafic lamprophyre dykes in Rio de Janeiro, Brazil.International Dyke Conference Held Feb. 6, India, 1p. AbstractSouth America, BrazilLamprophyre
DS201112-1066
2011
Valente, S.C.Valente, S.C.Mantle source components of the Early Cretaceous to Paleogene mafic tholeiitic and alkaline magmatism in Rio and related mantle metasomatism processes.Goldschmidt Conference 2011, abstract p.2058.South America, BrazilLamprophyre
DS200812-0023
2008
Valente, S.de C.Almeida, M.E., Macambira, M.J.B., Valente, S.de C.New geological and single zircon Pb evaporation dat a from the central Guyana Domain, southeastern Roraima, Brazil: tectonic implications for the central shield.Journal of South American Earth Sciences, Vol. 26, 3, Nov. pp. 318-328.South America, Brazil, GuyanaTectonics, Roraima
DS1994-1820
1994
Valentin, C.Valentin, C.Surface sealing as affected by various rock fragment covers in WestAfricaCatena, Vol. 23, pp. 87-97West Africa, Guinea, Burkina Faso, Ghana, Benin, NigeriaPaleosols, Regosols, weathering
DS201911-2517
2019
Valentine, A.P.Davies, D.R., Valentine, A.P., Kramer, S.C., Rawlinson, N., Hoggard, M.J., Eakin, C.M., Wilson, C.R.Earth's multi-scale topographic response to global mantle flow.Nature Geosciences, Vol. 12, pp. 845-850.Mantlegeodynamics

Abstract: Earth’s surface topography is a direct physical expression of our planet’s dynamics. Most is isostatic, controlled by thickness and density variations within the crust and lithosphere, but a substantial proportion arises from forces exerted by underlying mantle convection. This dynamic topography directly connects the evolution of surface environments to Earth’s deep interior, but predictions from mantle flow simulations are often inconsistent with inferences from the geological record, with little consensus about its spatial pattern, wavelength and amplitude. Here, we demonstrate that previous comparisons between predictive models and observational constraints have been biased by subjective choices. Using measurements of residual topography beneath the oceans, and a hierarchical Bayesian approach to performing spherical harmonic analyses, we generate a robust estimate of Earth’s oceanic residual topography power spectrum. This indicates water-loaded power of 0.5?±?0.35?km2 and peak amplitudes of up to ~0.8?±?0.1?km at long wavelengths (~104?km), decreasing by roughly one order of magnitude at shorter wavelengths (~103?km). We show that geodynamical simulations can be reconciled with observational constraints only if they incorporate lithospheric structure and its impact on mantle flow. This demonstrates that both deep (long-wavelength) and shallow (shorter-wavelength) processes are crucial, and implies that dynamic topography is intimately connected to the structure and evolution of Earth’s lithosphere.
DS1989-1536
1989
Valentine, G.A.Valentine, G.A.Magma transport through dykesNature, Vol. 342, December 7, pp. 614-625GlobalMagma, Dykes
DS2002-1629
2002
Valentine, G.A.Valentine, G.A., Zhang, D., Robinson, B.A.Modeling complex, nonlinear geological processesAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 35-64.GlobalModels - nonlinear processes
DS2002-1630
2002
Valentine, G.A.Valentine, G.A., Zhang, D., Robinson, B.A.Modeling complex, nonlinear geological processesAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 35-64.GlobalModels - nonlinear processes
DS200612-1458
2006
Valentine, G.A.Valentine, G.A., Perry, F.V.Decreasing magmatic footprints of individual volcanoes in a waning basaltic field.Geophysical Research Letters, Vol. 33, 14, L14305.MantleMagmatism
DS201312-0103
2013
Valentine, G.A.Brown, R.J., Valentine, G.A.Physical characteristics of kimberlite and basaltic intraplate volcanism and implications of a biased kimberlite record.Geological Society of America Bulletin, Vol. 125, pp. 1224-1238.GlobalKimberlite volcanism and erosion depths
DS201504-0226
2015
Valentine, G.A.Valentine, G.A., Graettinger, A.H, Macorps, E., Ross, P-S., White, J.D.L., Dohring, E., Sonder, I.Experiments with vertically and laterally migrating subsurface explosions with applications to the geology of phreatomagmatic and hydrothermal explosion craters and diatremes.Bulletin of Volcanology, Vol. 77, 15p.TechnologyDiatremes, kimberlites
DS201504-0227
2014
Valentine, G.A.Valentine, G.A., Graettinger, A.H, Sonder, I.Explosion depths for phreatomagmatic eruptions.Geophysical Research Letters, Vol. 41, pp. 3045-51.TechnologyMagmatism - phreatomagmatic
DS2002-1631
2002
Valentine, J.W.Valentine, J.W.Prelude to the Cambrian explosionAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 285-306.GlobalCambrian - overview
DS2002-1632
2002
Valentine, J.W.Valentine, J.W.Geologic structure of the uppermost oceanic crust created at fast to intermediate rate spreading centersAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 347-84.MantleTectonics
DS2002-1633
2002
Valentine, J.W.Valentine, J.W.Geologic structure of the uppermost oceanic crust created at fast to intermediate rate spreading centersAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 347-84.MantleTectonics
DS200712-1104
2007
Valentini, L.Valentini, L., Moore, K.R.The possible role of magma mixing in the petrogenesi of carbonatite silicate rock associations: a case study from the Kola alkaline province.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.233.Russia, Kola PeninsulaCarbonatite
DS200712-1105
2007
Valentini, L.Valentini, L., Moore, K.R.The possible role of magma mixing in the petrogenesi of carbonatite silicate rock associations: a case study from the Kola alkaline province.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.233.Russia, Kola PeninsulaCarbonatite
DS201012-0809
2010
Valentini, L.Valentini, L., Moore, K.R., Chazot, G.Unravelling carbonatite silicate magma interaction dynamics: a case study from the Velay province ( Massif Central, France).Lithos, Vol. 116, 1-2, pp. 53-64.Europe, FranceCarbonatite
DS201112-1067
2011
Valentini, L.Valentini, L.Modelling carbonatite-silicate interaction.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractCarbonatite
DS201112-1068
2010
Valentini, L.Valentini, L.Geochemical and numerical modelling of the interaction between carbonatite and silicate magmas.Department of Earth Sciences, College of Science National University of Ireland Galway, May 154p. * I have a copyRussia, Kola PeninsulaCarbonatite, petrology
DS201112-1069
2011
Valentini, L.Valentini, L.Modelling carbonatite silicate magma interaction.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.153-155.MantleMagmatism
DS201112-1070
2011
Valentini, L.Valentini, L.Modelling carbonatite silicate magma interaction.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.153-155.MantleMagmatism
DS201312-0932
2010
Valentini, L.Valentini, L.Geochemical and numerical modelling of the interaction between carbonatite and silicate magmas.Thesis, Dept. of Earth and Ocean Sciences, College of Science, National University of Ireland, Galway, 139p. Paper copy donated by R. SageRussia, FranceKola alkaline, Massif Central
DS1991-0540
1991
Valentino, D.W.Gates, A.E., Valentino, D.W.Late Proterozoic rift control on the shape of the Appalachians: the Pennsylvanian reentrantJournal of Geology, Vol. 99, pp. 863-872Midcontinent, AppalachiaTectonics, Proterozoic rift
DS1994-1821
1994
Valentino, D.W.Valentino, D.W., Gates, A.E., Glover, L.Late Paleozoic transcurrent tectonic assembly of the central AppalachianpiedmontTectonics, Vol. 13, No. 1, February, pp. 110-126AppalachiaTectonics
DS1993-1638
1993
ValetValet, J-P, Meynadier, L.Geomagnetic field intensity and reversals during the past four millionyears.Nature, Vol. 366, November 18, pp. 234-238.MantlePaleomagnetics, Geophysics -magnetics
DS200612-0744
2006
ValetKravchinsky, V.A., Konstantinov, Courtillot, Savrasov, Valet, Cherniy, Mishenin, ParasotkaPaleomagnetism of East Siberian traps and kimberlites: two new poles and paleogeographic reconstructions at about 360 and 250 Ma.Geophysical Journal International, Vol. 148, 1, pp. 1-33.Russia, SiberiaMaleomagnetics
DS1998-1505
1998
Valet, J.P.Valet, J.P., Gallet, Y.Paleomagnetism: ancient inclinationNature, Vol. 396, No. 6709, Nov. 26, pp. 315-6.MantleGeophysics - paleomagnetics
DS2003-0858
2003
Valet, J.P.Macouin, M., Valet, J.P., Besse, J., Buchan, K., Ernst, R., Le Goff, M., ScharerLow paleointensities recorded in 1 to 2.4. Ga Proterozoic dykes, Superior ProvinceEarth and Planetary Science Letters, Vol. 213, 1-2, pp. 79-95.Ontario, ManitobaGeochronology
DS200412-1193
2003
Valet, J.P.Macouin, M., Valet, J.P., Besse, J., Buchan, K., Ernst, R., Le Goff, M., Scharer, U.Low paleointensities recorded in 1 to 2.4. Ga Proterozoic dykes, Superior Province, Canada.Earth and Planetary Science Letters, Vol. 213, 1-2, pp. 79-95.Canada, Ontario, ManitobaGeochronology
DS200612-0847
2006
Valet, J.P.Macouin, M., Valet, J.P., Besse, J., Ernst, R.E.Absolute paleointensity at 1.27 Ga from the Mackenzie dyke swarm ( Canada).Geochemistry, Geophysics, Geosystems: G3, Vol. 7, Q01H21Canada, Northwest TerritoriesGeochronology, magnetiziation
DS1992-0306
1992
Valet, J-P.Courtillot, V., Valet, J-P., Hulot, G., Le Mouel, J-L.The earth's magnetic field: which geometry?Eos, Vol. 73, No. 32, August 11, p. 337, 340, 342GlobalGeophysics, Magnetic field
DS1992-1591
1992
Valet, J-P.Valet, J-P., Tucholka, P., Courtillot, V., Meynadier, L.Paleomagnetic constraints on the geometry of the geomagnetic field duringreversalsNature, Vol. 356, April 2, pp.400-407GlobalGeophysics -paleomagnetics, Geomagnetics
DS1994-1822
1994
Valeton, I.Valeton, I.Element concentration and formation of ore deposits by weatheringCatena, Special Issue on Laterization Processes and Supergene Ore, Vol. 21, No. 2-3, pp. 99-130Brazil, India, New Caledonia, AustraliaWeathering, Laterization -element concentration
DS1997-1187
1997
Valeton, I.Valeton, I., Schumann, A.Supergene alteration since Upper Cretaceous on alkaline igneous and metasomatic rocks of Pocos de Caldas Ring.Applied Geochemistry, Vol. 12, No. 2, March, 1, pp. 133-154Brazil, Minas GeraisLaterites, Alteration
DS1983-0153
1983
Valeyev, K.A.Brodskaya, S.YU., Valeyev, K.A.The Origin of Carbonatites of the Gulinskaya Alkaline Ultrabasic Intrusion.Physics Solid Earth, Vol. 19, No. 5, PP. 421-424.RussiaBlank
DS1995-2098
1995
Valin, Z.C.Yangshen, Shi, Huafu, L., Valin, Z.C.Paleozoic plate tectonic evolution of the Tarim and western Tianshanregions, western China.International Geology Review, Vol. 36, No. 11, Nov. pp. 1058-1066.ChinaTectonics
DS2002-1634
2002
Valislenko, V.B.Valislenko, V.B., Zinchuk, N.N., Krasavchikov, V.G., Kuznetsova, L.G.Diamond potential estimation based on kimberlite major element chemistryJournal of Geochemical Exploration, Vol. 76, 2, pp. 93-112.Russia, YakutiaChemistry, diamond grade, whole rock composition, Exploration - techniques
DS1996-0834
1996
Valizer, P.M.Lennykh, V.I., Valizer, P.M., Beane, R., et al.Petrotectonic evolution of the Maksyutov Complex, southern Urals, Russia:implications for metamorphismInternational Geology Review, Vol. 37, pp. 584-600.Russia, UralsPlate tectonics, Metamorphism -ultra high pressure
DS201012-0314
2010
Valizer, P.M.Ivanov, K.S., Valizer, P.M., Erokhin, Yu.V., Pogramoskaya, O.E.Genesis of carbonatites of fold belts ( exemplified by the Urals).Doklady Earth Sciences, Vol. 435, 1, pp. 1423-1426.Russia, UralsCarbonatite
DS201012-0412
2010
Valizer, P.M.Krasnobaev, A.A., Rusin, A.I., Valizer, P.M., Busharina, S.V.Zirconology of calcite carbonatite of the Vishnevogorsk massif, southern Urals.Doklady Earth Sciences, Vol. 431, 1, pp. 390-393.Russia, UralsCarbonatite
DS201312-0515
2013
Valizer, P.M.Krasnobaev, A.A., Valizer, P.M., Cherednichenko, S.V., Busharina, S.V., Medvedeva, E.V., Presyakov, S.L.Zirconology of carbonate rocks ( marbles-carbonatites) of the Ilmeno-Visnevogorskii complex, southern Urals.Doklady Earth Sciences, Vol. 450, 1, pp. 504-508.Russia, UralsCarbonatite
DS201412-0571
2014
Valizer, P.M.Medvedeva, E.V., Rusin, A.I., Krasnobaev, A.A., Baneva, N.N., Valizer, P.M.Structural compositional evolution and isotopic age of Ilmeny Vishnevogorsky complex, south urals, Russia.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, Russia, UralsCarbonatite
DS201610-1879
2016
Valla, P.G.King, G.E., Guralnik, B., Valla, P.G., Herman, F.Trapped charge thermochronometry and thermometry: a status review.Chemical Geology, in press available 15p.TechnologyThermometry

Abstract: Trapped-charge dating methods including luminescence and electron spin resonance dating have high potential as low temperature (< 100 °C) thermochronometers. Despite an early proof of concept almost 60 years ago, it is only in the past two decades that thermoluminescence (TL), electron-spin-resonance (ESR), and optically stimulated luminescence (OSL), have begun to gain momentum in geological thermochronometry and thermometry applications. Here we review the physics of trapped-charge dating, the studies that led to its development and its first applications for deriving palaeo-temperatures and/or continuous cooling histories. Analytical protocols, which enable the derivation of sample specific kinetic parameters over laboratory timescales, are also described. The key limitation of trapped-charge thermochronometry is signal saturation, which sets an upper limit of its application to < 1 Ma, thus restricting it to rapidly exhuming terrains (> 200 °C Ma? 1), or elevated-temperature underground settings (> 30 °C). Despite this limitation, trapped-charge thermochronometry comprises a diverse suite of versatile methods, and we explore potential future applications and research directions.
DS1996-0027
1996
Valladares, C.E.Anderson, D.N., Decker, D.T., Valladares, C.E.Modeling boundary blobs using time varying invectionGeophys. Research Letters, Vol. 23, No. 5, March 1, pp 579-582MantleGeophysics -seismics, Boundary
DS1970-1000
1974
Vallance, G.Vallance, G.Geology of the Country between Moyamba and Bo. Report on Reconnaissance Mapping Sheets 76, 77, 78, 79, 88, 89, 90.Geological Survey SIERRA LEONE Report, 56P.Sierra Leone, West AfricaGeology, Kimberlite
DS201112-1071
2011
Vallance, S.Vallance, S., Perkins, H.C., Dixon, J.E.What is social sustainability? A clarification of concepts.Geoforum, Vol. 42, 3, June pp. 342-348.TechnologyCSR Classification - overview of concept
DS2003-0140
2003
ValleeBouchon, ValleeSupersize shearsScience, No. 5634, Aug. 8, p. 824.MantleGeodynamics - structure
DS200412-0187
2003
ValleeBouchon, ValleeSupersize shears.Science, No. 5634, Aug. 8, p. 824.MantleGeodynamics - structure
DS1960-0830
1967
Vallee, M.Gold, D.P., Vallee, M., Charette, J.P.Economic Geology and Geophysics of the Oka Alkaline Complex, Quebec.The Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 60, PP. 1131-1144.Canada, QuebecBlank
DS1986-0294
1986
Vallee, M.Gold, D.P., Eby, G.M., Vallee, M.Carbonatites, diatremes and ultra alakaline rocks in the Okaarea, QuebecGeological Association of Canada (GAC) Field trip Guidebook, No. 21, 51pQuebecMonteregian, Aillikite, alnoite, okaite, carbonatite, ijolit, Melilite, glimmerite, Ile C.
DS1993-1471
1993
Vallee, M.Sinclair, A.J., Vallee, M.Reviewing continuity: an essential element of quality control for depositand reserve estimationThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Annual Meeting Preprint, Paper No. 33, 9pCanadaOre reserve estimation, classification, Geostatistics
DS1993-1767
1993
Vallee, M.Wortman, D., Taylor, H.K., Vallee, M.Discussion: Mineral deposit evaluation and reserve inventory practiceThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 86, No. 968, March pp. 144-148CanadaEconomics, ore reserves, Geostatistics
DS1994-0354
1994
Vallee, M.Cranstone, D., Lemieux, A., Vallee, M.Canadian exploration and mine investmentProspectors and Developers Association of Canada (PDAC) Exploration and Development Highlights, March 1994, pp. 3-8CanadaExploration activities and investment, Overview
DS1997-1188
1997
Vallee, M.Vallee, M., McCutcheon, S.Are international reporting standards feasible?The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 90, No. 1007, Feb. pp. 30-37GlobalGeostatistics, Economics, ore reserves, resources, terminology
DS1997-1189
1997
Vallee, M.Vallee, M., Sinclair, A.J.Efficient resource and reserve estimation depends on high quality geology and evaluation proceduresThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 90, No. 1011, June pp. 76-79GlobalGeostatistics, ore reserves, Evaluation, sampling
DS1998-1506
1998
Vallee, M.Vallee, M., Sinclair, A.Quality control of resource/reserve estimation - where do we go from here?The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 91, No. 1022, July/Aug. pp. 55-57CanadaGeostatistics, ore reserves, discoveries
DS1997-0799
1997
Vallee, O.Misser, F., Vallee, O.Les gemmocraties l'economie politique du diamant africain. (Political powerand markets)Paris, Descles de Brouwer, 243p.GlobalBook review Journal of Mat. Policy Vol. 13, No. 2, p. 41., Diamond markets
DS1991-1876
1991
Vallee, P.Williamson, P.A., da Silva, N.B., Vallee, P., Robey, J.V.The Moana-Tinguins melilitite province, Piaui state, northweasternProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 460-462BrazilTectonics, Mineral chemistry
DS2001-1234
2001
ValleyWiesli, R.A., Taylor, L., Valley, Tromsdorff, KurosawaGeochemistry of eclogites and metapelites from Trescolmen: as observed from major and trace elements..International Geology Review, Vol. 43, No. 2, pp. 95-119.AlpsEcolgites, Geochemistry
DS200712-0795
2007
ValleyPage, F.Z., Fu, B., Kita, N.T., Fournelle, Spicuzza, Schulze, Viljoen, Basei, ValleyZircons from kimberlite: new insights into oxygen isotopes, trace elements, and Ti in zircon thermometry.Geochimica et Cosmochimica Acta, Vol. 71, 15, pp. 3887-3903.TechnologyZircon thermometry
DS200912-0447
2009
ValleyLiu, Y., Taylor, L.A., Sarbadhikari, Valley, Ushikubo, Spicuzza, Kita, Ketchum, Carlson, Shatsky, SobolevMetasomatic origin of diamonds in the world's largest Diamondiferous eclogite.Lithos, In press - available 41p.RussiaDeposit - Udachnaya
DS201810-2360
2018
ValleyNasdala, L., Corfu, F., Schoene, B., Tapster, S.R., Wall, C.J., Schmitz, M.D., Ovtcharova, M., Schaltegger, U., Kennedy, A.K., Kronz, A., Reiners, P.W., Yang, Y-H., Wu, F-Y., Gain, S.E.M., Griffin, W.L., Szymanowski, D., Chanmuang, C., Ende, N.M., ValleyGZ7 and GZ8 - two zircon reference materials for SIMS U-Pb geochronology.Geostandards and Geoanalytical Research, http://orchid.org/0000-0002-2701-4635 80p.Asia, Sri Lankageochronology

Abstract: Here we document a detailed characterization of two zircon gemstones, GZ7 and GZ8. Both stones had the same mass at 19.2 carats (3.84 g) each; both came from placer deposits in the Ratnapura district, Sri Lanka. The U-Pb data are in both cases concordant within the uncertainties of decay constants and yield weighted mean ²??Pb/²³?U ages (95% confidence uncertainty) of 530.26 Ma ± 0.05 Ma (GZ7) and 543.92 Ma ± 0.06 Ma (GZ8). Neither GZ7 nor GZ8 have been subjected to any gem enhancement by heating. Structure?related parameters correspond well with the calculated alpha doses of 1.48 × 10¹? g?¹ (GZ7) and 2.53 × 10¹? g?¹ (GZ8), respectively, and the (U-Th)/He ages of 438 Ma ± 3 Ma (2s) for GZ7 and 426 Ma ± 9 Ma (2s) for GZ8 are typical of unheated zircon from Sri Lanka. The mean U concentrations are 680 ?g g?¹ (GZ7) and 1305 ?g g?¹ (GZ8). The two zircon samples are proposed as reference materials for SIMS (secondary ion mass spectrometry) U-Pb geochronology. In addition, GZ7 (Ti concentration 25.08 ?g g?¹ ± 0.18 ?g g?¹; 95% confidence uncertainty) may prove useful as reference material for Ti?in?zircon temperature estimates.
DS1998-0086
1998
Valley, J.Barth, M.G., Rudnick, R.L., Spicuzza, M.J., Valley, J.The role of eclogites in the growth of Archean cratons: a case study from west Africa.7th International Kimberlite Conference Abstract, pp. 52-54.GlobalMan Shield, eclogites, Deposit - Koidu
DS2003-1366
2003
Valley, J.Taylor, L.A., Spetsius, Z.A., Wiesli, R., Anand, M., Promprated, P., Valley, J.The origin of mantle peridotites: crustal signatures from Yakutian kimberlites8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractRussia, YakutiaMantle geochemistry
DS200412-1974
2003
Valley, J.Taylor, L.A., Snyder, G.A., Keller, R., Remley, D.A., Anand,M., Wiesli, R., Valley, J., Sobolev, N.V.Petrogenesis of Group A eclogites and websterites: evidence from the Obnazhennaya kimberlite, Yakutia.Contributions to Mineralogy and Petrology, Vol. 145, pp. 424-443.Russia, YakutiaPetrology, genesis Deposit - Obnazhennaya
DS200612-0122
2006
Valley, J.Bennett, V., Valley, J.Earth evolution 4.5 to 3.5 Ga: deciphering the earliest global systems.Goldschmidt Conference 16th. Annual, S5-02 theme abstract 1/8p goldschmidt2006.orgMantleTectonics
DS201605-0838
2016
Valley, J.Gaschnig, R.M., Rudnick, R.L., McDonough, W.F., Kaufman, A.J., Valley, J., Hu, Z., Gao, S., Beck, M.L.Compositional evolution of the upper continental crust through time, as constrained by ancient glacial diamictites.Geochimica et Cosmochimica Acta, in press available 78p.MantleBulk chemistry

Abstract: The composition of the fine-grained matrix of glacial diamictites from the Mesoarchean, Paleoproterozoic, Neoproterozoic, and Paleozoic, collected from four modern continents, reflect the secular evolution of the average composition of the upper continental crust (UCC). The effects of localized provenance are present in some cases, but distinctive geochemical signatures exist in diamictites of the same age from different localities, suggesting that these are global signatures. Archean UCC, dominated by greenstone basalts and less so komatiites, was more mafic, based on major elements and transition metal trace elements. Temporal changes in oxygen isotope ratios, rare earth elements, and high field strength elements indicate that the UCC became more differentiated and that tonalite-trondhjemite-granodiorite suites became less important with time, findings consistent with previous studies. We also document the concentrations of siderophile and chalcophile elements (Ga, Ge, Cd, In, Sn, Sb, W, Tl, Bi) and lithophile Be in the UCC through time, and use the data for the younger diamictites to construct a new estimate of average UCC along with associated uncertainties.
DS201901-0039
2018
Valley, J.Gu, T., Valley, J., Kitajima, K., Spicuzza, M., Fournelle, J., Stern, R., Ohfuji, H., Wang, W.Evidence of subducted altered oceanic crust into deep mantle from inclusions of type IaB diamonds,Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 306-7.Mantlediamond inclusions

Abstract: Nitrogen is one of the most common impurities in diamond, and its aggregation styles have been used as criteria for diamond classification. Pure type IaB diamonds (with 100% nitrogen in B aggregation) are rather rare among natural diamonds. The occurrence of the B center is generally associated with high temperature and a long residence time of the host diamond, which would potentially provide information on the earth’s deep interior. Seawater circulation is the unique process that shapes the surface of our planet and potentially has a profound effect on its interior due to slab subduction. In about 50 type IaB diamonds with detectable micro-inclusions submitted to GIA for screening, we found that more than 70% of them contained a typical mineral assemblage from the sublithosphere. Jeffbenite (TAPP), majorite garnet, enstatite, and ferropericlase have been observed, which could be retrograde products of former bridgmanite. CaSiO3-walstromite with larnite and titanite is the dominant phase present in approximately 40% of all diamond samples. Direct evidence from oxygen isotope ratios measured by secondary ion mass spectrometry, or SIMS, (?18OVSMOWin the range +10.7 to +12.5‰) of CaSiO3-walstromite with coexisting larnite and titanite that retrograde from CaSiO3-perovskite suggest that hydrothermally altered oceanic basalt can subduct to depths of >410 km in the transition zone. Incorporation of materials from subducted altered oceanic crust into the deep mantle produced diamond inclusions that have both lower mantle and subduction signatures. Ca(Si,Al)O3-perovskite was observed with a high concentration of rare earth elements (>5 wt.%) that could be enriched under P-Tconditions in the lower mantle. Evidence from ringwoodite with a hydroxide bond, coexisting tuite and apatite, precipitates of an NH3phase, and cohenite with trace amounts of Cl imply that the subducted brines can potentially introduce hydrous fluid to the bottom of the transition zone. In the diamonds with subducted materials, the increasing carbon isotope ratio from the core to the rim region detected by SIMS (?13C from -5.5‰ to -4‰) suggests that an oxidized carbonate-dominated fluid was associated with recycling of the subducted hydrous material. The deep subduction played an important role in balancing redox exchange with the reduced lower mantle indicated by precipitated iron nanoparticles and coexisting hydrocarbons and carbonate phases.
DS1995-1223
1995
Valley, J.M.Medaris, L.G., Beard, B.L., Johnson, O.H., Valley, J.M.Garnet pyroxenite and eclogite in the Bohemian Massif -geochemical evidence for Variscan recycling.Geologische Rundschau, Vol. 84, No. 3, Sept. pp. 489-505.GermanyEclogites, Subduction
DS2001-1039
2001
Valley, J.R.Schulze, D.K., Valley, J.R., Bell, D.R., Spicuzza, M.Oxygen isotope variations in Cromium poor megacrysts from kimberliteGeochimica et Cosmochimica Acta., Vol. 65, No. 23, pp. 4375-84.Ontario, South AfricaGeochronology, Chromium
DS200612-1345
2006
Valley, J.V.Spetsius, Z.V., Taylor, L.A., Valley, J.V., Ivanov, A.S., Banzeruk, V.L., Spicuzza, M.Garnets of anomalous oxygen isotope composition in Diamondiferous xenoliths Nyurbinskaya pipe, Yakutia.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 59-78.Russia, YakutiaDeposit - Nyurbaninskaya, mineralogy
DS1975-1013
1979
Valley, J.W.Essene, E.J., Valley, J.W.High Pressure Akermanite in the AdirondacksGeological Society of America (GSA), Vol. 11, No. 1, P. 11. (abstract.).United States, Appalachia, Canada, QuebecBlank
DS1990-1227
1990
Valley, J.W.Riciputi, L.R., Valley, J.W., McGregor, V.R.Conditions of Archean granulite metamorphism in theGodthab-Fiskenaessetregion, southern West GreenlandJournal of Metamorphic Geology, Vol. 8, No. 2, March pp. 171-190GreenlandMetamorphism, Granulite
DS1990-1500
1990
Valley, J.W.Van Wyck, N., Valley, J.W., Austrheim, H.Oxygen isotope geochemistry of granulites and eclogites from the Bergenarc, southwest NorwayGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A347NorwayEclogites, Geochemistry
DS1991-1524
1991
Valley, J.W.Schulze, D.J., Valley, J.W.Carbon isotope composition of mantle graphite: anomalously light carbon subducted into the shallow subcontinental lithosphereGeological Association of Canada (GAC)/Mineralogical Association of Canada/Society Economic, Vol. 16, Abstract program p. A112South AfricaGeochronology, Carbon-graphite
DS1991-1525
1991
Valley, J.W.Schulze, D.J., Valley, J.W., Viljoen, K.S., Spicuzza, M.Carbon isotope composition of graphite in mantle eclogitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 353-355South Africa, BotswanaXenoliths, Bellsbank, Jagersfontein, Orapa, Letlhakane, eclogites
DS1991-1772
1991
Valley, J.W.Valley, J.W.Ion microprobe analysis of oxygen isotopes in magnetite and ilmeniteEos, Spring Meeting Program And Abstracts, Vol. 72, No. 17, April 23, p. 292South AfricaGeochemistry, Monastery mine
DS1992-1592
1992
Valley, J.W.Valley, J.W.Granulite formation is driven by magmatic processes in the deep crustEarth Science Reviews, Vol. 32, pp. 145-146. Extended abstractGlobalGranulites, Magma
DS1994-1224
1994
Valley, J.W.Moecher, D.P., Valley, J.W., Essene, E.J.Extraction and carbon isotope analysis of CO2 from scapolite in deep crustal granulites and xenoliths.Geochimica et Cosmochimica Acta, Vol. 58, No. 2, January pp. 1031-1042.GlobalGeochronology, Xenoliths
DS1994-1961
1994
Valley, J.W.Yardley, B.W.D., Valley, J.W.How wet is the earth's crust?Nature, Vol. 371, Sept. 15, pp. 205-206MantleFluids, Basins
DS1995-0237
1995
Valley, J.W.Burgess, S.R., Graham, C.M., Valley, J.W., Harte, B.Oxygen isotope composition of metasomatised mantle peridotite xenoliths -laser fluorination/microprobeProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 83-85.South AfricaGeochronology, Deposit -Jagersfontein
DS1996-1091
1996
Valley, J.W.Peck, W.H., Valley, J.W.The Fisken asset anorthosite complex: stable isotope evidence for shallow emplacement -Archean ocean crustGeology, Vol. 24, No. 6, June pp. 523-526GreenlandGeochronology, Anorthosite -Fiskenaesset
DS1996-1404
1996
Valley, J.W.Taylor, L.A., Valley, J.W., Clayton, R.N., Snyder, G.A.Oxygen isotopes by laser-heating and conventional techniques a study of Siberian Diamondiferous eclogitesInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 1, p. 106.Russia, SiberiaGeochronology, Eclogites
DS1996-1467
1996
Valley, J.W.Van Wyck, N., Valley, J.W., Austrheim, H.Oxygen and carbon isotopic constraints on the development of eclogites, Holsnoy, Norway.Lithos, Vol. 38, No.3-4, Sept. 10, pp. 129-146.NorwayEclogites, Geochronology
DS1997-1010
1997
Valley, J.W.Schulze, D.J., Valley, J.W., Viljoen, K.S., StiefenhoferCarbon isotope composition of graphite in mantle ecologitesJournal of Geology, Vol. 105, No. 3, May pp. 379-386.South Africa, Wyoming, BotswanaEclogites, geochronology, Jagersfontein, Deposit - Schaffer, Letlhakane, Orapa, Bellsbank, Blaau
DS1997-1138
1997
Valley, J.W.Tardley, B.W.D., Valley, J.W.The petrologic case for a dry lower crustJournal of Geophysical Research, Vol. 102, No. 6, June 10, pp. 12, 173-86.MantlePetrology, Crust
DS1998-1301
1998
Valley, J.W.Schulze, D.J., Valley, J.W., Bell, D.R., Spicuzza, M.Significance of oxygen isotope variations in the chromium-poor megacryst suite7th. Kimberlite Conference abstract, pp. 769-71.South Africa, North AmericaKimberlite - Group I, II, Subduction
DS1998-1507
1998
Valley, J.W.Valley, J.W., Kinny, P.D., Spicuzza, M.J.Zircon megacrysts from kimberlite: oxygen isotope variability among mantlemelts.Contributions to Mineralogy and Petrology, Vol. 133, No. 1-2, pp. 1-11.MantleGeochronology, Megacryst - mineralogy
DS1999-0758
1999
Valley, J.W.Upton, B.G.J., Hinton, R.W., Valley, J.W.Megacrysts and associated xenoliths: evidence for migration of geochemically enriched melts upper mantleJournal of Petrology, Vol. 40, No. 6, June 1, pp. 935-56.MantleGeochemistry, Xenoliths
DS2000-0874
2000
Valley, J.W.Schulze, D.J., Valley, J.W., Spicuzza, M.J.Coesite eclogites from the Roberts Victor kimberlite, South AfricaLithos, Vol. 54, No. 1-2, Oct. pp. 23-32.South AfricaTectonics - subduction, Deposit - Roberts Victor
DS2001-0899
2001
Valley, J.W.Peck, W.H., Valley, J.W., Wilde, S.A., Graham, C.M.Oxygen isotope ratios and rare earth elements in 3.3 - 4.4 Ga zircons: ion microprobe evidence high 0 18...Geochimica et Cosmochimica Acta, Vol. 65, No. 22, pp. 4215-29.AustraliaGeochronology, Craton - Yilgarn
DS2001-1236
2001
Valley, J.W.Wilde, S.A., Valley, J.W., Graham, C.M.Evidence from detrital zircon for the existence of continental crust and ocean in the earth 4.4 Gyr ago.Nature, Vol. 409, No. 6817, Jan. 11, p. 175-7.MantleGeochronology
DS2002-1635
2002
Valley, J.W.Valley, J.W., Peck, W.H., King, E.M., Wilde, S.A.A cool early EarthGeology, Vol. 30,4,Apr.pp.351-4.MantleArchean - geochronology, impacts, meteorites
DS2003-1235
2003
Valley, J.W.Schultz, D.J., Valley, J.W., Specuzza, M.J., Channer, D.M.Oxygen isotope composition of eclogitic and peridotitic garnet xenocrysts from the LaInternational Geology Review, Vol. 45, No. 11, Nov. pp. 968-75.VenezuelaGeochronology
DS2003-1237
2003
Valley, J.W.Schulze, D.J., Harte, B., Valley, J.W., Brenan, J.M., DeR. Channer, D.M.Extreme crustal oxygen isotope signatures preserved in coesite diamondNature, No. 6935, May 1, p. 68-69.GlobalGeochronology
DS2003-1238
2003
Valley, J.W.Schulze, D.J., Valley, J.W., Viljoen, K.S., Spicuzza, M.J.Oxygen isotope composition of mantle eclogites8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractSouth Africa, ColoradoEclogites and Diamonds, Geochronology
DS2003-1272
2003
Valley, J.W.Shulze, D.J., Harte, B., Valley, J.W., Channer, D.M. DeR.Extreme geochemical variation during and following diamond growth, Guaniamo8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractVenezuelaEclogites, diamonds, Geochemistry
DS200412-1767
2003
Valley, J.W.Schulze, D.J., Harte, B., Valley, J.W., Brenan, J.M., DeR Channer, D.M.Extreme crustal oxygen isotope signatures preserved in coesite diamond.Nature, No. 6935, May 1, p. 68-69.TechnologyGeochronology
DS200412-1768
2004
Valley, J.W.Schulze, D.J., Harte, B., Valley, J.W., Channer, D.M.De R.Evidence of subduction and crust mantle mixing from a single diamond.Lithos, Vol. 77, 1-4, Sept. pp. 349-358.South America, Venezuela, GuaniamoGarnet, carbon oxygen isotopes, geochonology
DS200412-1769
2003
Valley, J.W.Schulze, D.J., Valley, J.W., Specuzza, M.J., Channer, D.M.Oxygen isotope composition of eclogitic and peridotitic garnet xenocrysts from the La Ceniza kimberlite, Guaniamo, Venezuela.International Geology Review, Vol. 45, no. 11, Nov. pp. 968-75.South America, VenezuelaGeochronology
DS200412-1814
2003
Valley, J.W.Shulze, D.J., Harte, B., Valley, J.W., Channer, D.M.DeR.Extreme geochemical variation during and following diamond growth, Guaniamo, Venezuela.8 IKC Program, Session 2, AbstractSouth America, VenezuelaEclogite, diamonds Geochemistry
DS200512-0145
2005
Valley, J.W.Cavosie, A.J., Valley, J.W., Wilde, S.A.Magmatic delta 18 O in 4400-3900 Ma detrial zircons: a record of the alteration and recycling of crust in the Early Archean.Earth and Planetary Science Letters, Vol. 235, 1-4, July 15, pp. 663-681.AustraliaMagmatism - not specific to diamonds
DS200512-1114
2005
Valley, J.W.Valley, J.W.A cool early Earth.Scientific American, October pp.MantleGeothermometry
DS200612-1246
2006
Valley, J.W.Schultz, D.J., Harte, B., Valley, J.W., Channer, D.M.DeR.Diamonds with multiple growth stages and variable fluid sources from the Quebrada Grande region of Guaniamo, Venezuela.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p. 137.South America, VenezuelaDiamond morphology
DS200612-1418
2005
Valley, J.W.Taylor, L.A., Spetsius, Z.V., Wiesli, R., Spicuzza, M., Valley, J.W.Diamondiferous peridotites from oceanic protoliths: crustal signatures from Yakutian.Russian Geology and Geophysics, Vol. 46, 12, pp. 1176-1184.RussiaPeridotite - diamond morphology
DS200612-1459
2006
Valley, J.W.Valley, J.W.Early Earth.Elements, Vol. 3, no. 4, August pp. 201-204.MantleGeochronology, zircon, life
DS200612-1460
2005
Valley, J.W.Valley, J.W., Lackey, J.S., Cavosie, A.J., Clechenko, C.C., Spicuzza, M.J., Basei, M.A.S., Bindeman, I.N.4.4 billion years of crustal maturation: oxygen isotope ratios.Contributions to Mineralogy and Petrology, Vol. 150, 8, Dec. pp. 561-580.MantleGeochronology
DS200712-0960
2007
Valley, J.W.Schulze, D.J., Page, F.Z., Valley, J.W., Harte, B., Kita, N., Channer, D.M.,Jaques, L.Quasi-correlation between carbon and oxygen isotope signatures in eclogitic diamonds and their mineral inclusions.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, Volume 32, 1 pg. abstract p.73-74.South America, Venezuela, Australia, Africa, BotswanaGeochronology
DS200712-1106
2007
Valley, J.W.Valley, J.W.Evidence of the earliest crust on Earth.Plates, Plumes, and Paradigms, 1p. abstract p. A1051.AustraliaGeochronology
DS200812-0132
2008
Valley, J.W.Bowman, J.R., Moser, D.E., Wooden, J.L., Valley, J.W., Mazdab, F.K., Kita, N.Cathodluminescence CL isotopic Pb O and trace element zoning in lower crustal zircon documents growth of early continental lithosphere.Goldschmidt Conference 2008, Abstract p.A107.Canada, OntarioKapuskasing Uplift
DS200812-0372
2008
Valley, J.W.Fu, B., Page, F.Z., Cavosie, A.J., Fournelle, J., Kita, N.T., Lackey, J.S., Wilde, S.A., Valley, J.W.Ti in zircon thermometry: applications and limitations.Contributions to Mineralogy and Petrology, 37p. in press availableTechnologyGeothermometry - kimberlites
DS200812-0584
2008
Valley, J.W.Konish, H., Xu, H., Spicuzza, M.,Valley, J.W.Polycrystalline diamond inclusions in Jack Hills zircon: carbonado?Goldschmidt Conference 2008, Abstract p.A489.AustraliaDiamond inclusions
DS200812-0767
2008
Valley, J.W.Moser, D.E., Bowman, J.R., Wooden, J., Valley, J.W., Mazdab, F., Kita, N.Creation of a continent recorded in zircon zoning.Geology, Vol. 36, 3 March pp. 239-242.Canada, OntarioGeochronology - Kapuskasing
DS200812-1103
2008
Valley, J.W.Spetsius, Z.V., Taylor, L.A., Valley, J.W., DeAngelsi, M., Spicuzza, M., Ivanov, A.S., Banzeruk, V.I.Diamondiferous xenoliths from crustal subduction: garnet oxygen isotopes from the Nyurbinskaya pipe, Yakutia.European Journal of Mineralogy, Vol. 20, no. 3, pp. 375-385.Russia, YakutiaDeposit - Nyurbinskaya
DS200812-1194
2008
Valley, J.W.Ushikobo, T., Kita, N.T., Cavosie, A.J., Wilde, S.A., Rudnick, R.L., Valley, J.W.Lithium in Jack Hills zircon: evidence for extreme weathering of Earth's crust at 4300 Ma.Goldschmidt Conference 2008, Abstract p.A968.AustraliaWeathering
DS200812-1195
2008
Valley, J.W.Ushikubo, T., Kita, N.T., Cavosie, A.J., Wilde, S.A., Rudnick, R.L., Valley, J.W.Lithium in Jack Hills zircons: evidence for extensive weathering of Earth's earliest crust.Earth and Planetary Science Letters, Vol. 272, 3-4, pp. 666-676.AustraliaGeochronology, Hadean
DS201012-0589
2010
Valley, J.W.Pivin, M., Valley, J.W., Spicuzza, M.J., Demaiffe, D.Oxygen isotopic composition of garnet clinopyroxene and zircon megacrysts from kimberlites in Democratic Republic of Congo: insights into their petrogenesis.International Mineralogical Association meeting August Budapest, abstract p. 560.Africa, Democratic Republic of CongoDeposit - Mbuji-Mayi
DS201112-0982
2011
Valley, J.W.Sobolev, N.V., Schertl, H-P., Valley, J.W., Page, F.Z., Kita, N.T., Spicuzza, M.J., Neuser, R.D., Logvinova, A.M.Oxygen isotope variations of garnets and clinopyroxenes in a layered Diamondiferous calcsilicate rock from Kokchetav Massif, Kazakhstan: a window into geochemicalContributions to Mineralogy and Petrology, Vol. 162, 5, pp.1079-1092.Russia, KazakhstanDeeply subducted UHPM rocks
DS201212-0609
2012
Valley, J.W.Russell, A.K., Kitajima, K., Strickland, A., Medaris, L.G.Jr., Schulze, D.J., Valley, J.W.Eclogite facies fluid infiltration: constraints from delta 10 O zoning in garnet.Contributions to Mineralogy and Petrology, in press available, 14p.Europe, NorwayEclogite
DS201312-0794
2013
Valley, J.W.Schulze, D., Harte, B., Page, F.Z., Valley, J.W., DeR Channer, D.M., Jaques, A.L.Anticorrelation between low d13c of eclogitic diamonds and high d180 of their coesite and garnet inclusions requires a subduction origin.Geology, Vol. No. 4, pp. 455-458.South America, Venezuela, Australia, Africa, BotswanaDeposit - Guaniamo, Arygle, Orapa
DS201412-0676
2014
Valley, J.W.Pernet-Fisher, J.F., Howarth, G.H., Liu, Y., Barry, P.H., Carmody, L., Valley, J.W., Bodnar, R.J., Spetsius, Z.V., Taylor, L.A.Komsomolskaya Diamondiferous eclogites: evidence for oceanic crustal protoliths.Contributions to Mineralogy and Petrology, Vol. 167, pp. 1-17.Russia, SiberiaDeposit - Komsomolskaya
DS201412-0938
2014
Valley, J.W.Valley, J.W., Cavosie, T., Ushikubo, T., Reinhard, D.A., Lawrence, D.F., Larson, D.J., Clifton, P.H., Kelly, T.F., Wilde, S.A., Moser, D.E., Spicuzza, M.J.Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography.Nature Geoscience, Vol. 7, pp.219-223.MantleGeochronology
DS201505-0243
2015
Valley, J.W.Katzir, Y., Anenburg, M., Kaminchik, J., Segev, A., Blichert-Toft, J., Spicuzza, M.J., Valley, J.W.Garnet pyroxenites as markers of recurring extension and magmatism at the rifted margins of the Levant basin.Israel Geological Society, Abstracts 1p.Europe, Israel, Mt. CarmelPyroxenite
DS201509-0434
2015
Valley, J.W.Valley, J.W., Reinhard, D.A., Cavosie, A.J., Ushikubo, T., Lawrence, D.F., Larson, D.J., Kelly, T.F., Snoeyenbos, D.R., Strickland, A.Nano- and micro-geochronology in Hadean and Archean zircons by atom-probe tomography and SIMS: new tools for old minerals.American Mineralogist, Vol. 100, pp. 1355-1377.AustraliaGeochronology

Abstract: Atom-probe tomography (APT) and secondary ion mass spectrometry (SIMS) provide complementary in situ element and isotope data in minerals such as zircon. SIMS measures isotope ratios and trace elements from 1–20 ?m spots with excellent accuracy and precision. APT identifies mass/charge and three-dimensional position of individual atoms (±0.3 nm) in 100 nm-scale samples, volumes up to one million times smaller than SIMS. APT data provide unique information for understanding element and isotope distribution; crystallization and thermal history; and mechanisms of mineral reaction and exchange. This atomistic view enables evaluation of the fidelity of geochemical data for zircon because it provides new understanding of radiation damage, and can test for intracrystalline element mobility. Nano-geochronology is one application of APT in which Pb isotope ratios from sub-micrometer domains of zircon provide model ages of crystallization and identify later magmatic and metamorphic reheating.
DS202012-2219
2020
Valley, J.W.Hoover, W.F., Page, F.Z., Schulze, D.J., Kitajima, K., Valley, J.W.Massive fluid influx beneath the Colorado Plateau ( USA) related to slab removal and diatreme emplacement: evidence from oxygen isotope zoning in eclogite xenoliths.Journal of Petrology, in press available, 52p. PdfUnited States, Colorado Plateaueclogite

Abstract: The Colorado Plateau has undergone as much as 1.8?km of uplift over the past 80?Ma, but never underwent the pervasive deformation common in the neighboring tectonic provinces of the western USA. To understand the source, timing and distribution of mantle hydration, and its role in plateau uplift, garnets from four eclogite xenoliths of the Moses Rock diatreme (Navajo Volcanic Field, Utah, USA) were analyzed in situ for ?18O by secondary ion mass spectrometry. These garnets have the largest reported intra-crystalline oxygen isotope zoning to date in mantle-derived xenoliths with core-to-rim variations of as much as 3‰. All samples have core ?18O values greater than that of the pristine mantle (?5.3‰, mantle garnet as derived from mantle zircon; Valley et al., 1998; Page et al., 2007) consistent with an altered upper oceanic crust protolith. Oxygen isotope ratios decrease from core to rim recording interaction with a low-?18O fluid at high temperature, likely derived from serpentinite in the foundering Farallon slab. All zoned samples converge at a ?18O value of ?6‰, regardless of core composition, suggesting that fluid infiltration was widely distributed. Constraints on the timing of this fluid influx, relative to diatreme emplacement, can be gained from diffusion modeling of major element zoning in garnet. Modeling using best-estimates of peak metamorphic conditions (620ºC, 3.7?GPa) yield durations of?
DS1994-0586
1994
Vallier, T.L.Geist, E.L., Vallier, T.L., Scholl, D.W.Origin, transport, and emplacement of an exotic island arc terrane expose din eastern Kamchatka, Russia.Geological Society of America (GSA) Bulletin., Vol. 106, No. 9, Sept. pp. 1182-1994.RussiaTectonics, Paleomagnetism, Ophiolite
DS2001-0342
2001
Vallis, F.FruhGreen, G.L., Scamelluri, M., Vallis, F.Oxygen and Hydrogen isotope ratios of high pressure ultramafic rocks: implications for fluid sources and mobility mantle...Contributions to Mineralogy and Petrology, Vol. 141, No. 1, pp. 145-59.MantleSubduction - hydrous mantle, Oxygen, Hydrogen, Geochronology
DS1997-1014
1997
Vallve, M.Seber. D., Vallve, M., et al.Middle East Tectonics: applications of geographic information systems(GIS)Gsa Today, Vol. 7, No. 2, Feb. pp. 1-7GlobalTectonics, Computers - GIS
DS2000-0191
2000
Valsami-JonesCotter-Howells, J., Campbell, Valsami-Jones, BatchelderEnvironmental mineralogy: microbial interactions, anthropegenic influences, contaimined land and waste management.Mineralogical Society of America, No. 9, 414p. $ 70.GlobalBook - ad, Mineralogy, environment
DS1984-0788
1984
Valter, A.A.Yeremenko, G.K., Valter, A.A.Abyssal Inclusions of Proterozoic Camptonites of the Azov Region.Geolog. Zhurn., Vol. 44, No. 3, PP. 59-65.RussiaBlank
DS1990-1491
1990
Valter, A.A.Valter, A.A., Kvasnitsa, V.N., Yeremenko, G.K.Structure, composition and optical properties of diamond paramorphs bygraphite.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 3, pp. 3-16RussiaDiamond, Crystallography
DS1991-1773
1991
Valter, A.A.Valter, A.A., Kolesov, G.M.Distribution of rare earth elements in astrobleme rocksGeochemistry International, Vol. 28, No. 1, pp. 1-11Russiarare earth elements (REE)., Geochemistry
DS1991-1774
1991
Valter, A.A.Valter, A.A., Kvasnitsa, .N.The genetic types of natural diamondsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 569-570RussiaDiamond morphology, Mantle, ultrabasic, peridotite, eclogite, metamorphic
DS2003-1404
2003
Valter, A.A.Valter, A.A., Oleynik, H.S., Fisenko, A.V., Semenova, I.F.Structural and morphological evidence of the impact induced development of diamondGeochemistry International, Vol. 41, 10, pp. 939-946.GlobalMeteoritic - diamond
DS2003-1405
2003
Valter, A.A.Valter, A.A., Oleynik, H.S., Fisenko, A.V., Semenova, L.F.Structural and morphological evidence from impact induced development of diamondGeochemistry International, Vol. 41, 10, pp. 939-46.GlobalMicromorphology - martensite transformation
DS200412-2031
2003
Valter, A.A.Valter, A.A., Oleynik, H.S., Fisenko, A.V., Semenova, L.F.Structural and morphological evidence from impact induced development of diamond after graphite in the Novo-Urei meteorite.Geochemistry International, Vol. 41, 10, pp. 939-46.TechnologyMicromorphology - martensite transformation
DS2003-0864
2003
Valuev, E.P.Mahotkin, I.L., Robey, J., Kurszlaukis, S., Valuev, E.P., Pylaev, N.F.Pipe emplacement model of the Lomonosov diamond deposit, Arkangelsk region, NW8 Ikc Www.venuewest.com/8ikc/program.htm, Session 1, AbstractRussiaGeology, economics, Deposit - Lomonosov
DS200412-1203
2003
Valuev, E.P.Mahotkin, I.L., Robey, J., Kurszlaukis, S., Valuev, E.P., Pylaev, N.F.Pipe emplacement model of the Lomonosov diamond deposit, Arkangelsk region, NW Russia.8 IKC Program, Session 1, AbstractRussiaGeology, economics Deposit - Lomonosov
DS2000-0971
2000
Valverde-Vaquero, P.Valverde-Vaquero, P., Dorr, Belka, Franke, WiszniewskaUranium-lead (U-Pb) single grain dating of detrital zircon in the Cambrian of central Poland: implications for GondwanaEarth and Planetary Science Letters, Vol. 184, No.1, Dec.30, pp. 225-40.GlobalTectonics - Baltica, Trans European Suture Zone - not specific to diamonds
DS202011-2050
2020
Van, K.V.Limanov, E.V., Butvina, V.G., Safonov, O.G., Van, K.V., Aranovich, L. Ya.Phlogopite formation in the orthopyroxene-garnet system in the presence of H2O-KCL fluid to the processes of mantle metasomatism.Doklady Earth Sciences, Vol. 494, 1, pp. 713-717.Russiametasomatism

Abstract: The results of experimental studies are presented for reactions in the orthopyroxene-garnet-phlogopite system in the presence of H2O-KCl fluid at 3-5 GPa and 900-1000°C, which model the processes of phlogopite formation in garnet peridotites and pyroxenites during alkaline metasomatism of the upper mantle. The experiments demonstrated regular variations in the composition of garnet, pyroxenes, and phlogopite depending on the KCl content of the fluid. With increasing KCl content of the fluid, enstatite and garnet become unstable, the Al2O3 content of enstatite decreases, and the amount of grossular and knorringite components in garnet are maximum at a KCl content of ~10 mol %. Our results illustrate well the regular variations in the compositions of the coexisting minerals and their zoning in phlogopite-bearing peridotites of the lithospheric mantle.
DS2003-1406
2003
Van Achetrbergh, E.Van Achetrbergh, E., Ryan, C.G., Griffin, W.L., O'Reilly, S.Y.Natural trace element distribution between immiscible silicate and carbonate melts8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractNorthwest TerritoriesDeposit - A 154N Lac de Gras
DS200412-2032
2003
Van Achetrbergh, E.Van Achetrbergh, E., Ryan, C.G., Griffin, W.L., O'Reilly, S.Y.Natural trace element distribution between immiscible silicate and carbonate melts imaged by nuclear microprobe.8 IKC Program, Session 7, POSTER abstractCanada, Northwest TerritoriesKimberlite petrogenesis Deposit - A 154N Lac de Gras
DS1998-1139
1998
Van AchterberghPearson, N.J., Griffin, Kaminsky, Van AchterberghTrace element discrimination of garnet from Diamondiferous kimberlites andlamproites.7th. Kimberlite Conference abstract, pp. 673-5.South Africa, Russia, Siberia, Yakutia, Venezuela, GhanaGeochemistry, Garnets
DS2000-0363
2000
Van AchterberghGriffin, W.L., Pearson, N., Bolousova, Van AchterberghThe hafnium isotope composition of cratonic mantle: LAM MC ICPMS analysis of zircon megacrysts in kimberlites.Geochimica et Cosmochimica Acta, Vol. 64, pp. 133-47.AustraliaGeochronology
DS2001-1178
2001
Van Achterbergh, A.E.Van Achterbergh, A.E., Griffin, Kivi, Pearson, O'ReillyCarbonatites at 200 km: quenched melt inclusions in megacrystalline lherzolite xenoliths Slave Craton.Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 35.(abs)Northwest TerritoriesCarbonatite, A 154 kimberlite
DS2001-1179
2001
Van Achterbergh, A.E.Van Achterbergh, A.E., Griffin, W.L., Stiefenhofer, J.Metasomatism in mantle xenoliths from the Letlhakane kimberlites: estimation of element fluxes.Contributions to Mineralogy and Petrology, Vol. 141, No. 4, pp. 397-414.BotswanaXenoliths - alteration, Deposit - Letlhakane
DS1998-1508
1998
Van Achterbergh, E.Van Achterbergh, E., Griffin, W.L., Shee, S.R., WyattNatural trace element distribution coefficients for garnet, clino-orthopyroxene: variations T and P.7th International Kimberlite Conference Abstract, pp. 934-6.South AfricaXenoliths, Metasomatism, Deposit - Wesselton
DS1998-1509
1998
Van Achterbergh, E.Van Achterbergh, E., Griffin, W.L., Steifenhofer, J.Xenoliths from the Letlhakane kimberlite: geochemistry and implications for mantle processes.7th International Kimberlite Conference Abstract, pp. 937-9.BotswanaHarzburgite, lherzolite, Metasomatism, Deposit - Latlhakane
DS2002-1636
2002
Van Achterbergh, E.Van Achterbergh, E., Griffin, W.L., Ryan, C.G., O'Reilly, S.Y., Pearson, N.J.Subduction signature for quenched carbonatites from the deep lithosphereGeology, Vol.30,8,Aug.pp.743-6.MantleSubduction, Carbonatite
DS2003-1407
2003
Van Achterbergh, E.Van Achterbergh, E., Griffin, W.L., O'Reilly, S.Y., Ryan, C.G., Pearson, N.J.Melt inclusions from the deep Slave lithosphere: constraints on the origin and evolution8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractNorthwest TerritoriesDiamonds - melting
DS200412-2033
2003
Van Achterbergh, E.Van Achterbergh, E., Griffin, W.L., O'Reilly, S.Y., Ryan, C.G., Pearson, N.J., Kivi, K., Doyle, B.J.Melt inclusions from the deep Slave lithosphere: constraints on the origin and evolution of mantle derived carbonatite and kimbe8 IKC Program, Session 3, AbstractCanada, Northwest TerritoriesDiamonds - melting
DS200612-1461
2006
Van Achterbergh, E.Van Achterbergh, E., O'Reilly, S.Y., Griffin, W.L.The origin of fertile enstatite by deep seated carbonatite metasomatism.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 3, abstract only.MantleCarbonatite
DS200912-0008
2009
Van Achterbergh, E.Araujo, D.P., Griffin, W.L., O'Reilly, S.Y., Grant, K.J., Ireland, T., Van Achterbergh, E.Micro inclusions in monocrystalline octahedral diamonds and coated diamonds from Diavik, Slave Craton: clues to diamond genesis.Lithos, In press available 38p.Canada, Northwest TerritoriesDeposit - Diavik
DS201112-1072
2005
Van Achterbergh, E.Van Achterbergh, E.Geochemical fingerprints of mantle metasomatism.Thesis: Macquarie University Phd. , MantleThesis: note availability based on request to author
DS200712-1107
2007
Van Acken, D.Van Acken, D., Becker, H., Wombacher, Walker, McDonough, Ash, PiccoliFractionated HSE in suboceanic mantle: assessing the influence of refertilization processes on upper mantle peridotites.Plates, Plumes, and Paradigms, 1p. abstract p. A1051.Europe, SwitzerlandWebsterite
DS200812-1186
2007
Van Acken, D.Trumbull, R.B., Reid, D.L., De Beer, C., Van Acken, D., Romer, R.L.Magmatism and continental breakup at the west margin of southern Africa: a geochemical comparison of dolerite dikes from northwestern Namibia and the Western Cape.South African Journal of Geology, Vol. 110, 2-3, Sept. pp. 477-502.Africa, South Africa, NamibiaMagmatism
DS200812-1198
2008
Van Acken, D.Van Acken, D., Becker, H., Walker, R.J.Refertilization of Jurassic oceanic peridotites from the Tethys Ocean: implications for the Re Os systematics of the upper mantle.Earth and Planetary Science Letters, Vol. 268, 1-2, pp. 171-181.MantlePeridotite
DS201609-1748
2016
van Acken, D.Tappe, S., Brand, N.B., Stracke, A., van Acken, D., Liu, C-Z., Strauss, H., Wu, F-Y., Luguet, A., Mitchell, R.H.Plates or plumes in the origin of kimberlites: U/PB perovskite and Sr-Nd-Hf-Os-C-O isotope constraints from the Superior craton ( Canada).Chemical Geology, in press available 85p.Canada, QuebecDeposit - Renard, Wemindji

Abstract: Neoproterozoic kimberlite, ultramafic lamprophyre, and carbonatite magmatic activity was widespread across the Canadian-Greenland Shield. Models to explain the preponderance of this deeply-derived CO2-rich magmatism between 680-540 Ma range from impingement of multiple mantle plumes to rifting activity linked to the breakout of the Laurentian plate from the Rodinia supercontinent configuration. We add to the debate about the origin of kimberlite magmas and evaluate possible mantle sources of the 655 Ma ‘diamond-rich’ Renard (new SIMS U/Pb perovskite ages) and 629 Ma ‘barren’ Wemindji kimberlites on the eastern Superior craton in Quebec, Canada. Our Sr-Nd-Hf and carbon isotope data (87Sr/86Sri = 0.70241-0.70442; ?Ndi = + 0.2 to + 4.8; ?Hfi = + 0.3 to + 6.5; ?13C = ? 5.6 to ? 3.9‰) suggest a common and moderately depleted convecting upper mantle source region for both the Renard and Wemindji kimberlites, which occur 400-km apart in the interior of the Superior craton. In contrast, the low Os isotope ratios (187Os/188Osi = 0.11078-0.12620; ?Osi = ? 13.7 to ? 1.6) and unfractionated chondritic relative HSE abundances (Os, Ir, Ru, Pt, Pd, Re) indicate significant involvement of ancient refractory cratonic mantle material in kimberlite magma formation. Our model calculations suggest that for both the diamond-rich Renard and the barren Wemindji kimberlite magmas up to 30% of the Os was derived from refractory cratonic peridotites. This material might have been assimilated by originally more CO2-rich carbonated silicate melts derived from the asthenosphere. We also show that the geochemical and Sr-Nd-Hf-Os isotopic compositions of the Renard and Wemindji kimberlites do not require significant input from melts derived from olivine-poor cratonic mantle lithologies such as MARID-type veins and pyroxenites/eclogites. This contrasts with the petrogenesis of deeply-derived volatile-rich potassic magmas found along the peripheries of cratons (e.g., ultramafic lamprophyres, kamafugites, and olivine lamproites), a setting where abundant non-peridotitic components have been added to the lithospheric mantle over the course of continent evolution. Provided that CO2-rich melts, such as proto-kimberlites, occur near the solidus of volatile-fluxed peridotites, no excess mantle heat is required in their formation. This important but often overlooked constraint, together with the observation that there exist no spatial or temporal relationships between the Superior craton kimberlites and Large Igneous Provinces during the Late Neoproterozoic, suggests that kimberlite magmatic activity was tectonically controlled. In our preferred model, ubiquitous CO2-rich proto-kimberlite melts form during volatile-controlled redox melting processes at ambient mantle temperatures in a thermal boundary layer directly beneath thick cratonic lithosphere. The success rate of ‘evolving’ hybrid kimberlite magmas reaching Earth’s surface increases when tensile stresses propagate into the > 200 km thick keels of continental lithosphere. These conditions are frequently met during fast and changing plate motions associated with the assembly and breakup of supercontinents.
DS201612-2341
2016
van Acken, D.Tappe, S., Brand, N.B., Strackc, A., van Acken, D., Lie, C-Z., Strausf, H., Wu, F-Y., Luguet, A., Mitchell, R.H.Plates or plumes in the origin of kimberlites: U/PB perovskite and Sr-Nd-Hf-Os-C-O isotope constraints from the Superior craton ( Canada).Chemical Geology, on line August 27p.Canada, QuebecDeposit - Renard, Wemindji

Abstract: Neoproterozoic kimberlite, ultramafic lamprophyre, and carbonatite magmatic activity was widespread across the Canadian-Greenland Shield. Models to explain the preponderance of this deeply-derived CO2-rich magmatism between 680-540 Ma range from impingement of multiple mantle plumes to rifting activity linked to the breakout of the Laurentian plate from the Rodinia supercontinent configuration. We add to the debate about the origin of kimberlite magmas and evaluate possible mantle sources of the 655 Ma ‘diamond-rich’ Renard (new SIMS U/Pb perovskite ages) and 629 Ma ‘barren’ Wemindji kimberlites on the eastern Superior craton in Quebec, Canada. Our Sr-Nd-Hf and carbon isotope data (87Sr/86Sri = 0.70241-0.70442; ?Ndi = + 0.2 to + 4.8; ?Hfi = + 0.3 to + 6.5; ?13C = ? 5.6 to ? 3.9‰) suggest a common and moderately depleted convecting upper mantle source region for both the Renard and Wemindji kimberlites, which occur 400 km apart in the interior of the Superior craton. In contrast, the low Os isotope ratios (187Os/188Osi = 0.11078-0.12620; ?Osi = ? 13.7 to ? 1.6) and unfractionated chondritic relative HSE abundances (Os, Ir, Ru, Pt, Pd, Re) indicate significant involvement of ancient refractory cratonic mantle material in kimberlite magma formation. Our model calculations suggest that for both the diamond-rich Renard and the barren Wemindji kimberlite magmas up to 30% of the Os was derived from refractory cratonic peridotites. This material might have been assimilated by originally more CO2-rich carbonated silicate melts derived from the asthenosphere. We also show that the geochemical and Sr-Nd-Hf-Os isotopic compositions of the Renard and Wemindji kimberlites do not require significant input from melts derived from olivine-poor cratonic mantle lithologies such as MARID-type veins and pyroxenites/eclogites. This contrasts with the petrogenesis of deeply-derived volatile-rich potassic magmas found along the peripheries of cratons (e.g., ultramafic lamprophyres, kamafugites, and olivine lamproites), a setting where abundant non-peridotitic components have been added to the lithospheric mantle over the course of continent evolution. Provided that CO2-rich melts, such as proto-kimberlites, occur near the solidus of volatile-fluxed peridotites, no excess mantle heat is required in their formation. This important but often overlooked constraint, together with the observation that there exist no spatial or temporal relationships between the Superior craton kimberlites and Large Igneous Provinces during the Late Neoproterozoic, suggests that kimberlite magmatic activity was tectonically controlled. In our preferred model, ubiquitous CO2-rich proto-kimberlite melts form during volatile-controlled redox melting processes at ambient mantle temperatures in a thermal boundary layer directly beneath thick cratonic lithosphere. The success rate of ‘evolving’ hybrid kimberlite magmas reaching Earth’s surface increases when tensile stresses propagate into the > 200 km thick keels of continental lithosphere. These conditions are frequently met during fast and changing plate motions associated with the assembly and breakup of supercontinents.
DS201703-0436
2017
Van Acken, D.Van Acken, D., Luguet, A., Pearson, D.G., Nowell, G.M., Fonseca, R.O.C., Nagel, T.J., Schulz, T.Mesoarchean melting and Neoarchean ro Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland.Geochimica et Cosmochimica Acta, Vol. 203, pp. 37-53.Europe, GreenlandCraton
DS201707-1375
2017
van Acken, D.Tappe, S., Brand, N.B., Stracke, A., van Acken, D., Liu, C-Z., Strauss, H., Wu, F-Y., Luguet, A., Mitchell, R.H.Plates or plumes in the origin of kimberlites: U/pb perovskite and Sr-Nd-Hf-Os-C-O isotope contraints from the Superior craton ( Canada).Chemical Geology, Vol. 455, pp. 57-83.Canadadeposit - Renard, Wemndiji

Abstract: Neoproterozoic kimberlite, ultramafic lamprophyre, and carbonatite magmatic activity was widespread across the Canadian-Greenland Shield. Models to explain the preponderance of this deeply-derived CO2-rich magmatism between 680–540 Ma range from impingement of multiple mantle plumes to rifting activity linked to the breakout of the Laurentian plate from the Rodinia supercontinent configuration. We add to the debate about the origin of kimberlite magmas and evaluate possible mantle sources of the 655 Ma ‘diamond-rich’ Renard (new SIMS U/Pb perovskite ages) and 629 Ma ‘barren’ Wemindji kimberlites on the eastern Superior craton in Quebec, Canada. Our Sr-Nd-Hf and carbon isotope data (87Sr/86Sri = 0.70241–0.70442; ?Ndi = + 0.2 to + 4.8; ?Hfi = + 0.3 to + 6.5; ?13C = ? 5.6 to ? 3.9‰) suggest a common and moderately depleted convecting upper mantle source region for both the Renard and Wemindji kimberlites, which occur 400 km apart in the interior of the Superior craton. In contrast, the low Os isotope ratios (187Os/188Osi = 0.11078–0.12620; ?Osi = ? 13.7 to ? 1.6) and unfractionated chondritic relative HSE abundances (Os, Ir, Ru, Pt, Pd, Re) indicate significant involvement of ancient refractory cratonic mantle material in kimberlite magma formation. Our model calculations suggest that for both the diamond-rich Renard and the barren Wemindji kimberlite magmas up to 30% of the Os was derived from refractory cratonic peridotites. This material might have been assimilated by originally more CO2-rich carbonated silicate melts derived from the asthenosphere. We also show that the geochemical and Sr-Nd-Hf-Os isotopic compositions of the Renard and Wemindji kimberlites do not require significant input from melts derived from olivine-poor cratonic mantle lithologies such as MARID-type veins and pyroxenites/eclogites. This contrasts with the petrogenesis of deeply-derived volatile-rich potassic magmas found along the peripheries of cratons (e.g., ultramafic lamprophyres, kamafugites, and olivine lamproites), a setting where abundant non-peridotitic components have been added to the lithospheric mantle over the course of continent evolution. Provided that CO2-rich melts, such as proto-kimberlites, occur near the solidus of volatile-fluxed peridotites, no excess mantle heat is required in their formation. This important but often overlooked constraint, together with the observation that there exist no spatial or temporal relationships between the Superior craton kimberlites and Large Igneous Provinces during the Late Neoproterozoic, suggests that kimberlite magmatic activity was tectonically controlled. In our preferred model, ubiquitous CO2-rich proto-kimberlite melts form during volatile-controlled redox melting processes at ambient mantle temperatures in a thermal boundary layer directly beneath thick cratonic lithosphere. The success rate of ‘evolving’ hybrid kimberlite magmas reaching Earth’s surface increases when tensile stresses propagate into the > 200 km thick keels of continental lithosphere. These conditions are frequently met during fast and changing plate motions associated with the assembly and breakup of supercontinents.
DS201809-2060
2018
van Acken, D.Liu, J., Brin, L.E., Pearson, D.G., Bretschneider, L., Luguet, A., van Acken, D., Kjarsgaard, B., Riches, A., Miskovic, A.Diamondiferous Paleoproterozoic mantle roots beneath Arctic Canada: a study of mantle xenoliths from Parry Peninsula and Central Victoria Island.Geochimica et Cosmochimica Acta, doi.org/10.1016/j.gca.2018.08.010 78p.Canada, Nunavut, Parry Peninsula. Central Victoria Islandxenoliths

Abstract: While the mantle roots directly beneath Archean cratons have been relatively well studied because of their economic importance, much less is known about the genesis, age, composition and thickness of the mantle lithosphere beneath the regions that surround the cratons. Despite this knowledge gap, it is fundamentally important to establish the nature of relationships between this circum-cratonic mantle and that beneath the cratons, including the diamond potential of circum-cratonic regions. Here we present mineral and bulk elemental and isotopic compositions for kimberlite-borne mantle xenoliths from the Parry Peninsula and Central Victoria Island, Arctic Canada. These xenoliths provide key windows into the lithospheric mantle underpinning regions to the North and Northwest of the Archean Slave craton, where the presence of cratonic material has been proposed. The mantle xenolith data are supplemented by mineral concentrate data obtained during diamond exploration. The mineral and whole rock chemistry of peridotites from both localities is indistinguishable from that of typical cratonic mantle lithosphere. The cool mantle paleogeotherms defined by mineral thermobarometry reveal that the lithospheric mantle beneath the Parry Peninsula and Central Victoria Island terranes extended well into the diamond stability field at the time of kimberlite eruption, and this is consistent with the recovery of diamonds from both kimberlite fields. Bulk xenolith Se and Te contents, and highly siderophile element (including Os, Ir, Pt, Pd and Re) abundance systematics, plus corresponding depletion ages derived from Re-Os isotope data suggest that the mantle beneath these parts of Arctic Canada formed in the Paleoproterozoic Era, at ?2?Ga, rather than in the Archean. The presence of a diamondiferous Paleoproterozoic mantle root is part of the growing body of global evidence for diamond generation in mantle roots that stabilized well after the Archean. In the context of regional tectonics, we interpret the highly depleted mantle compositions beneath both studied regions as formed by mantle melting associated with hydrous metasomatism in the major Paleoproterozoic Wopmay-Great Bear-Hottah arc systems. These ?2?Ga arc systems were subsequently accreted along the margin of the Slave craton to form a craton-like thick lithosphere with diamond potential thereby demonstrating the importance of subduction accretion in building up Earth’s long-lived continental terranes.
DS201809-2062
2018
Van Acken, D.Liu, J., Pearson, D.G., Bretschneider, L., Luguet, A., Van Acken, D., Kjarsgaard, B., Riches, A., Miskovic, A.Diamondiferous Proterozoic mantle roots beneath Arctic Canada.Goldschmidt Conference, 1p. AbstractCanada, Parry Peninsula, Victoria Islandxenoliths

Abstract: The mantle roots directly beneath Archean cratons have been relatively well studied because of their economic importance, yet much less is known about the genesis, age, composition and thickness of the mantle lithosphere beneath the regions surrounding these cratons. However, it is critically important to establish the nature of the relationship between this circum-cratonic mantle and that beneath the cratons, including the diamond potential of circum-cratonic regions. Here we present mineral and bulk elemental and isotopic compositions for kimberlite-borne mantle xenoliths from the Parry Peninsula (PP) and Central Victoria Island (CVI), Arctic Canada. These xenoliths provide key windows into the lithospheric mantle underpinning regions to the North and Northwest of the Slave craton, where the presence of cratonic mantle has been proposed. The mineral and whole rock chemistry of peridotites from both localities is indistinguishable from that of typical cratonic mantle lithosphere. The cool mantle geotherms defined by mineral thermobarometry reveal that the lithospheric mantle beneath the PP and CVI terranes extended well into the diamond stability field at the time of kimberlite eruption, consistent with the recovery of diamonds from both kimberlite fields. Bulk Se, Te, and highly siderophile element abundance systematics, plus Re-Os isotope age data suggest that the mantle beneath these parts of Arctic Canada formed at ~2 Ga, rather than in the Archean. The presence of a diamondiferous Paleoproterozoic mantle root is part of the growing body of evidence for peridotitic diamond generation in mantle roots that stabilized well after the Archean. In the context of regional tectonics, the highly depleted mantle compositions beneath both regions developed during mantle melting associated with hydrous metasomatism in the major Paleoproterozoic Wopmay- Great Bear-Hottah arc systems. These terranes were subsequently accreted along the margin of the Slave craton to form a craton-like thick lithosphere with significant diamond potential.
DS202009-1669
2020
van Acken, D.Tappe, S., Stracke, A., van Acken, D., Strauss, H., Luguet, A.Origins of kimberlites and carbonatites during continental collision - insights beyond decoupled Nd-Hf isotopes. Earth-Science Reviews, in press available 72p.Global, Africa, South Africadeposit - Cullinan

Abstract: During the past two decades significant progress has been made in understanding the origin and evolution of kimberlites, including relationships to other diamondiferous magma types such as lamproites and aillikites. However, the association of kimberlites and carbonatites on continental shields remains poorly understood, and two opposing ideas dominate the debate. While one school of thought argues that primary carbonatite melts transform into hybrid carbonated silicate magmas akin to kimberlites by assimilation of cratonic mantle material, others use geochemical evidence to show that carbonatite magmas can evolve from near-primary kimberlite melts within the cratonic lithosphere. The 1.15 Ga Premier kimberlite pipe on the Kaapvaal craton in South Africa hosts several kimberlite and carbonatite dykes. Reconstructions of magma compositions suggest that up to 20 wt.% CO2 was lost from near-primary kimberlite melts during ascent through the cratonic lithosphere, but the carbonatite dyke compositions cannot be linked to the kimberlite melts via differentiation. Geochemical evidence, including mantle-like ?13C compositions, suggests that the co-occurring kimberlite and carbonatite dykes represent two discrete CO2-rich magma batches derived from a mixed source in the convecting upper mantle. The carbonatites probed a slightly more depleted source component in terms of Sr-Nd-Hf isotopic compositions relative to the peridotitic matrix that was more effectively tapped by the kimberlites (87Sr/86Sri = 0.70257 to 0.70316 for carbonatites vs. 0.70285 to 0.70546 for kimberlites; ?Ndi = +3.0 to +3.9 vs. +2.2 to +2.8; ?Hfi = -2.2 to +0.7 vs. -5.1 to -1.9). Platinum-group element systematics suggest that assimilation of refractory lithospheric mantle material by the carbonatite melts was negligible (<1 vol.%), whereas between 5 - 35 vol.% of digested cratonic peridotite account for the kimberlite compositions, including the low 187Os/188Os signature (?Osi = -12.7 to -4.5). The kimberlite and carbonatite dykes show similarly strong Nd-Hf isotope decoupling (??Hfi = -10.7 to -7.6 vs. -8.8 to -6.1), regardless of the variable lithospheric mantle imprints. This observation suggests a common sublithospheric origin of the negative ??Hf signature, possibly linked to ancient recycled oceanic crust components in the convecting upper mantle to transition zone sources of CO2-rich magmatism. Mesoproterozoic kimberlite and carbonatite magmatism at Premier was coeval with subduction and collision events along the southern Kaapvaal craton margin during the 1,220 -1,090 Ma Namaqua-Natal orogeny associated with Rodinia supercontinent formation. Thermochronology suggests that the entire Kaapvaal craton was affected by this collisional tectonic event, and it appears that the changing lithospheric stress-field created pathways for deep-sourced kimberlite and carbonatite magmas to reach Earth’s surface. We find that collision-induced (e.g., Premier) and continental breakup-related (e.g., Kimberley) kimberlite magmas are compositionally indistinguishable, with the inference that plate tectonic processes aid solely in the creation of magma ascent pathways without a major influence on deep mantle melting beneath cratons. It follows that on-craton kimberlite magmatism in the hinterland of collision zones is not necessarily more likely to entrain large sublithospheric diamonds than kimberlite eruptions linked to continental breakup. This implies that Premier’s world-class endowment with ‘ultradeep’ Type-II diamonds is not causally related to its setting behind an active orogenic front.
DS1999-0545
1999
Van ActerberghPearson, Griffin, Doyle, O'Reilly, Van Acterbergh, KiviXenoliths from kimberlite pipes of the Lac de Gras area, Slave Craton, Canada. (DO18, 27, A154S)7th International Kimberlite Conference Nixon, Vol. 2, pp. 644-58.Northwest TerritoriesPetrography, mineral chemistry, analyses, thermometry
DS200512-0369
2005
Van Acterbergh, E.Griffin, W.L., Natapov, L.M., O Reilly, S.Y., Van Acterbergh, E., Cherenkova, A.F., Cherenkov, V.G.The Kharamai kimberlite field, Siberia: modification of the lithospheric mantle by the Siberian Trap event.Lithos, Vol. 81, 1-4, pp. 167-187.Russia, SiberiaMetasomatism
DS200412-1258
2004
Van Aken, P.A.McCammon, C.A., Lauterbach, S., Seifert, F., Langenhorst, F., Van Aken, P.A.Iron oxidation state in lower mantle mineral assemblages. Part 2.Earth and Planetary Science Letters, Vol. 222, 2, pp. 435-449.MantleMineral chemistry
DS2002-1023
2002
Van Akern, P.McCammon, C., Lauterbach, S., Van Akern, P., Langenhorst, F., Seifert, F.EELS studies of lower mantle mineral assemblages: a window to redox conditions18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.77.MantleUHP mineralogy - perovskite
DS1986-0827
1986
Van Allen, B.R.Van Allen, B.R., Emmons, D.L., Paster, T.P.Carbonatite dike of the Chupadera Mountains, Socorro County, New MexicoNew Mexico Geology, Vol. 8, No. 2, May pp. 25-29., p. 40United States, Colorado Plateau, New MexicoCarbonatite
DS1991-1775
1991
Van Allen, J.A.Van Allen, J.A.Why radiation belts existEos, Vol. 72, n0. 34, August 20, pp. 361, 363GlobalRadiation, Magnetosphere
DS1950-0359
1957
Van antwerpen, C.Van antwerpen, C.Diamonds All over the World. #2Brussels, Edition Du Marais, 38P.GlobalPromotional, Kimberley
DS2001-0111
2001
Van Ark, E.M.Bina, C.R., Stein, S., Marton, F.C., Van Ark, E.M.Implications of slab mineralogy for subduction dynamicsPhysics of the Earth and Planetary Interiors, Vol. 127, No. 1-4, Dec. 1, pp. 51-66.MantleMineralogy - slab, Subduction - geodynamics
DS1990-1492
1990
Van Arsdale, E.B.Van Arsdale, E.B., Scherer, G.G., Schweig, E.S., Williams, R.A.Seismic reflection survey of Crowley's Ridge ArkansawEos, Vol. 71, No. 43, October 23, p. 1435 AbstractArkansasGeophysics -seismics, Crowley's Ridge
DS2002-0334
2002
Van Arsdale, R.B.Cox, R.T., Van Arsdale, R.B.The Mississippi embayment, North America: a first order continental structure generated by the Cretaceous superplume mantle event.Journal of Geodynamics, Vol.34,pp. 163-76.Kansas, Appalachia, MidcontinentTectonics, superplume, hotspot
DS201702-0247
2016
Van Avendonk, H.J.AVan Avendonk, H.J.A, Davis, J.K., Harding, J.L.Decrease in oceanic crustal thickness since the break up of Pangea.Nature Geoscience, Vol. 10, pp. 58-61.MantleTectonics

Abstract: Earth’s mantle has cooled by 6-11?°C every 100 million years since the Archaean, 2.5 billion years ago. In more recent times, the surface heat loss that led to this temperature drop may have been enhanced by plate-tectonic processes, such as continental breakup, the continuous creation of oceanic lithosphere at mid-ocean ridges and subduction at deep-sea trenches. Here we use a compilation of marine seismic refraction data from ocean basins globally to analyse changes in the thickness of oceanic crust over time. We find that oceanic crust formed in the mid-Jurassic, about 170 million years ago, is 1.7?km thicker on average than crust produced along the present-day mid-ocean ridge system. If a higher mantle temperature is the cause of thicker Jurassic ocean crust, the upper mantle may have cooled by 15-20?°C per 100 million years over this time period. The difference between this and the long-term mantle cooling rate indeed suggests that modern plate tectonics coincide with greater mantle heat loss. We also find that the increase of ocean crustal thickness with plate age is stronger in the Indian and Atlantic oceans compared with the Pacific Ocean. This observation supports the idea that upper mantle temperature in the Jurassic was higher in the wake of the fragmented supercontinent Pangaea due to the effect of continental insulation.
DS201703-0451
2016
Van Avendonk, H.J.AVan Avendonk, H.J.A, Davis, J.K., Harding, J.L.Decrease in oceanic crustal thickness since the break up of Pangea.Nature Geoscience, Vol. 10, pp. 58-61.MantleTectonics

Abstract: Earth’s mantle has cooled by 6-11?°C every 100 million years since the Archaean, 2.5 billion years ago. In more recent times, the surface heat loss that led to this temperature drop may have been enhanced by plate-tectonic processes, such as continental breakup, the continuous creation of oceanic lithosphere at mid-ocean ridges and subduction at deep-sea trenches. Here we use a compilation of marine seismic refraction data from ocean basins globally to analyse changes in the thickness of oceanic crust over time. We find that oceanic crust formed in the mid-Jurassic, about 170 million years ago, is 1.7?km thicker on average than crust produced along the present-day mid-ocean ridge system. If a higher mantle temperature is the cause of thicker Jurassic ocean crust, the upper mantle may have cooled by 15-20?°C per 100 million years over this time period. The difference between this and the long-term mantle cooling rate indeed suggests that modern plate tectonics coincide with greater mantle heat loss. We also find that the increase of ocean crustal thickness with plate age is stronger in the Indian and Atlantic oceans compared with the Pacific Ocean. This observation supports the idea that upper mantle temperature in the Jurassic was higher in the wake of the fragmented supercontinent Pangaea due to the effect of continental insulation.
DS1998-1510
1998
Van Balen, R.T.Van Balen, R.T., Heeremans, M.Middle Proterozoic early Paleozoic evolution of central Baltoscandi nan intracratonic basins: evidence diapirs..Tectonophysics, Vol. 300, No. 1-4, Dec. 31, pp. 131-42.Norway, Sweden, ScandinaviaTectonic, Craton - Baltoscandia
DS1998-1511
1998
Van Balen, R.T.Van Balen, R.T., Podladchikov, Y.Y., Cloetingh, S.A.P.L.A new multilayered model for intraplate stress induced differential subsidence of faulted lithosphere..Tectonics, Vol. 17, No. 6, Dec. pp. 938-54.GlobalBasins - rift, Subduction
DS201605-0876
2016
Van Bart, A.Mzimela, B., Kothao, L., Van Bart, A.Reducing the risk of mud flow events in block cave drawpoints through water abstraction.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 105-116.TechnologyMining - applied
DS1997-0257
1997
Van Beek, A.J.J.De Boorder, H., Van Beek, A.J.J., Panov, B.S.Crustal architecture of the Donets Basin: tectonic implications for diamond and mercury-antimony mineralsTectonophysics, Vol. 268, No. 1/4, Dec. 31, pp. 293-UKraineTectonics, Structure, Diamond mineralization, genesis
DS201112-0373
2011
Van Beek, P.H.Gleeson, T., Smith, L., Moosdorf, N., Hartmann, J., Durr, H.H., manning, A.H., Van Beek, P.H., Jellinek, A.Mapping permeability over the surface of the Earth.Geophysical Research Letters, Vol. 38, L02401MantleGeophysics
DS1981-0075
1981
Van bergen, M.J.Barton, M., Van bergen, M.J.Green Clinopyroxenes and Associated Phases in a Potassium Rich Lava from the Leucite Hills, Wyoming.Contributions to Mineralogy and Petrology, Vol. 77, No. 3, PP. 101-114.GlobalLeucite Hills, Leucite
DS1983-0614
1983
Van bergen, M.J.Van bergen, M.J., Ghezzo, C., Ricci, C.A.Minette inclusions in the rhyodacitic lavas of Mt. Amiata(CentralItaly); mineralogical and chemical evidence of mixing between Tuscan and Roman type lavasJournal of Vol. Geotherm. Research, Vol. 19, No. 1-2, pp. 1-35ItalyMinette
DS1992-1598
1992
Van bergen, M.J.Varekamp, J.C., Kreulen, R., Poorter, R.P.E., Van bergen, M.J.Carbon sources in arc volcanism, with implications for the carbon cycleTerra Nova, Vol. 4, pp. 363-373GlobalArc volcanism., Carbon cycle
DS201112-0740
2011
Van Bergen, M.J.Nikogosian, I.K., Van Bergen, M.J.Near source composition of Italian kamafugite melt.Goldschmidt Conference 2011, abstract p.1541.Europe, ItalyMagmatism
DS201312-0648
2013
Van Bergen, M.J.Nikogosian, I., Van Bergen, M.J., Chaneva, S.Multiple origins of carbon in Italian kamafugite melt.Goldschmidt 2013, AbstractEurope, ItalyKamafugite
DS201806-1233
2018
van Bergen, M.J.Koornneef, J.M., Berndsen, M., Hageman, L., Gress, M.U., Timmerman, S., Nikogosian, I., van Bergen, M.J., Chinn, I.L., Harris, J.W., Davies, G.R.Melt and mineral inclusions as messengers of volatile recycling in space and time. ( olivine hosted inclusions)Geophysical Research Abstracts www.researchgate.net, Vol. 20, EGU2018-128291p. AbstractAfrica, South Africadiamond inclusions

Abstract: Changing recycling budgets of surface materials and volatiles by subduction of tectonic plates influence the compositions of Earth’s major reservoirs and affect climate throughout geological time. Fluids play a key role in processes governing subduction recycling, but quantifying the exact fate of volatiles introduced into the mantle at ancient and recent destructive plate boundaries remains difficult. Here, we report on the role of fluids and the fate of volatiles and other elements at two very different tectonic settings: 1) at subduction settings, and 2) within the subcontinental lithospheric mantle (SCLM). We will show how olivine-hosted melt inclusions from subduction zones and mineral inclusions in diamond from the SCLM are used to reveal how changing tectonic settings influence volatile cycles with time. Melt inclusions from the complex Italian post-collisional tectonic setting are used to identify changing subduction recycling through time. The use of CO2 in deeply trapped melt inclusions instead of in lavas or volcanic gases provides a direct estimate of deep recycling, minimizing possible effects of contamination during transfer through the crust. The aim is to distinguish if increased recycling of sediments from the down-going plate at continental subduction settings results in increased deep CO2 recycling or if the increased CO2 flux results from crustal degassing of the overriding plate. Both processes likely affected climate through Earth history but could thus far not be discriminated. The study of mineral inclusions and their host diamonds from the SCLM can link changes in the cycling of carbon-rich fluids and the time and process through which the carbon redistribution took place. We use Sm-Nd isotope techniques to date the mineral inclusions and use the carbon isotope data of the host diamonds to investigate the growth conditions. I will present case-studies of peridotitic and eclogitic diamonds from three mines in Southern Africa.
DS201908-1782
2019
van Bergen, M.J.Koornneef, J.M., Nikogosian, I., van Bergen, M.J., Vroon, P.Z., Davies, G.R.Ancient recycled lower crust in the mantle source of recent Italian magmatism.Nature Communications, doi.org/10.1038/ s41467-019-11072-5 10p. PdfEurope, Italysubduction

Abstract: Recycling of Earth’s crust through subduction and delamination contributes to mantle heterogeneity. Melt inclusions in early crystallised magmatic minerals record greater geochemical variability than host lavas and more fully reflect the heterogeneity of magma sources. To date, use of multiple isotope systems on small (
DS1990-1493
1990
Van Bever Donker, J.M.Van Bever Donker, J.M., Humphreys, H.C., Swartz, H.G., Domoney, R.N.The history of deformation along the boundary between an Archean craton And a Proterozoic island arcTerra, Abstracts of Crustal Dynamics: Pathways and Records held Bochum FRG, Vol. 2, December p. 20South AfricaCraton -Kaapvaal, Tectonics
DS1988-0722
1988
Van Blerck, M.C.Van Blerck, M.C.Mining tax: income tax capital allowances granted to South african gold and natural oil MinesJournal of South African Institute of Mining and Metallurgy (IMM), Vol. 88, No. 7, July pp. 227-232. Database # 17379South AfricaEconomics, Legal -taxes
DS1994-1823
1994
Van Blerck, M.C.Van Blerck, M.C.Mining and the environment: tax incentives encourage orderly planningSouth African Institute of Mining and Metallurgy (IMM), June pp. 129-132South AfricaLaw, legal, Environment
DS1993-1639
1993
Van Bockstael, M.Van Bockstael, M.Western Australian diamondsBulletin. Soc. Belge de Geologie, Vol. 101, No. 1, 2, pp. 55-63.AustraliaLamproites, Deposit -Argyle
DS201610-1853
2014
Van Bockstael, M.Chirico, P.G., Malpeti, K.C., Van Bockstael, M., Mamandou, D., Cisse, K., Diallo, T.A., Sano, M.Alluvial diamond resource potential and production capacity assessment of Guinea.U.S. Geological Survey, Report 2012-5256, 49p.Africa, GuineaAlluvials, resources

Abstract: In May of 2000, a meeting was convened in Kimberley, South Africa, by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that export shipments of rough diamonds were free of conflict concerns. Outcomes of the meeting were formally supported later in December of 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme (KPCS) was ratified and signed by diamond-producing and diamond-importing countries. The goal of this study was to estimate the alluvial diamond resource endowment and the current production capacity of the alluvial diamond mining sector of Guinea. A modified volume and grade methodology was used to estimate the remaining diamond reserves within Guinea’s diamondiferous regions, while the diamond-production capacity of these zones was estimated by inputting the number of artisanal miners, the number of days artisans work per year, and the average grade of the deposits into a formulaic expression. Guinea’s resource potential was estimated to be approximately 40 million carats, while the production capacity was estimated to lie within a range of 480,000 to 720,000 carats per year. While preliminary results have been produced by integrating historical documents, five fieldwork campaigns, and remote sensing and GIS analysis, significant data gaps remain. The artisanal mining sector is dynamic and is affected by a variety of internal and external factors. Estimates of the number of artisans and deposit variables, such as grade, vary from site to site and from zone to zone. This report has been developed on the basis of the most detailed information available at this time. However, continued fieldwork and evaluation of artisanally mined deposits would increase the accuracy of the results.
DS202011-2066
2020
Van Bockstael, S.Van Bockstael, S.From boom to bust, and back again: the Tortiya diamond fields of Cote d'Ivoire, 1947-2018.Canadian Journal of Development Studies, Vol. 41, 3, pp. 450-466. pdfAfrica, Ivory Coasthistory

Abstract: Implementation of the African Mining Vision in Côte d’Ivoire is weak, and AMV domestication is unlikely to happen soon. Focusing on the artisanal and small-scale mining (ASM) sector, a key section of the AMV, we look at the tumultuous recent history of the diamond mining town Tortiya. The subject of a halting and uneven formalisation process, the case is emblematic for the lack of interest shown in ASM at a policy level. This is due to high costs, and low political and economic returns of formalisation. It underscores a broader lack of strategic vision for the mining sector.
DS200512-0834
2005
Van BreemanPehrsson, S.L., Berman, R.G., Rainbird, R., Davis, W., Skulski, Sanborn-Barrie, Van Breeman, Corrigan, TellaInterior collisional orogenesis related to supercontinent assembly: the ca. 1.9- 1.5 Ga tectonic history of the western Churchill province.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Canada, SaskatchewanNuna, tectonics
DS200512-0402
2005
Van Breeman, O.Harper, C.T., Van Breeman, O., Wodick,N., Pehrsson, S., Heaman, L., Hartlaub, R.The Paleoproterozoic lithostructural history and thermotectonic reactivation of the Archean basement in southern Hearne domain of northeastern Saskatchewan.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Canada, SaskatchewanTrans Hudson orogen
DS200912-0079
2009
Van Breeman, O.Buchan, K.L., LeCheminant, A.N., Van Breeman, O.Paleomagnetism and UPb geochronology of the Lac de Gras diabase dyke swarm, Slave Province, Canada: implications for relative drift of Slave and SuperiorCanadian Journal of Earth Sciences, Vol. 46, 5, May pp.361-379.Canada, Northwest TerritoriesPaleproterozoic
DS201012-0077
2010
Van Breeman, O.Buchan, K.L., Ernst, R.E., Bleeker, W., Davis, W.J., Villeneuve, M., Van Breeman, O., Hamilton, SoderlundMap of Proterozoic magmatic events in the Slave Craton, Wopmay Orogen and environs, Canadian Shield.International Dyke Conference Held Feb. 6, India, 1p. AbstractCanada, Northwest TerritoriesMagmatism
DS201012-0511
2010
Van Breeman, O.Mitchell, R.N., Van Breeman, O., Buchan, K.L., Le Cheminant, T.N., Bleeker, W., Evans, D.A.D.Supercratons at the ends of Early Proterozoic Earth: reconstruction of Slave, Superior, and Kaapvaal cratons at 2200-2000 Ma.International Dyke Conference Held Feb. 6, India, 1p. AbstractCanada, Africa, South AfricaKenorland
DS2001-0352
2001
Van BreemenGandhi, S.S., Mortensen, J.K., Prasad, N., Van BreemenMagmatic evolution of the southern Great Bear continental arc, northwestern Canadian shield....Canadian Journal of Earth Sciences, Vol. 38, No. 5, May, pp. 767-85.Northwest TerritoriesGeochronology - Slave Craton
DS2001-0912
2001
Van BreemenPeterson, T.D., Van Breemen, Sandeman, CousensPostorogenic granitoids and ultrapotassic rocks in the Hinterland of the Trans Hudson Orogen.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p. 117.abstract.Saskatchewan, GreenlandMinettes
DS1990-0380
1990
Van Breemen, O.Culshaw, N., Van Breemen, O.A zoned low pressure-high T complex at the level of anatexis- structural and plutonic patterns in metasediments of the Archean Yellowknife Supergroup, near Bathurst InletPrecambrian Research, Vol. 48, pp. 1-20Northwest TerritoriesArchean Yellowknife Supergroup, Tectonics
DS1992-0661
1992
Van Breemen, O.Hanmer, S., Bowring, S., Van Breemen, O., Parrish, R.Great Slave Lake shear zone, northwest Canada: mylonitic record of early Proterozoic continental convergence, collision and indentationJournal of Structural Geology, Vol. 14, No. 7, pp. 757-773Northwest TerritoriesStructure Tectonics, Shear zone
DS1992-0708
1992
Van Breemen, O.Higgins, M.D., Van Breemen, O.The age of Lac Saint Jean anorthosite intrusion and associated mafic rocksCanadian Journal of Earth Sciences, Vol. 29, pp. 1412-23.QuebecGeochronology
DS1994-0187
1994
Van Breemen, O.Bostock, H.H., Van Breemen, O.Ages of detrital and metamorphic zircons, monazites a pre-Taltson magmatic zone basin w edge of Rae Province.Canadian Journal of Earth Sciences, Vol. 31, No. 8, August, pp. 1353-1364.Northwest TerritoriesGeochronology, tectonics, craton, Rae Province
DS1994-0361
1994
Van Breemen, O.Currie, K.L., Van Breemen, O.Tectonics and age of the Kipawa syenite complex, western QuebecGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p.QuebecTectonics, Kipawa Syenite
DS1994-1009
1994
Van Breemen, O.LeCheminant, A.N., Van Breemen, O.uranium-lead (U-Pb) (U-Pb) ages of Proterozoic dyke swarms, Lac de Gras area, Northwest Territories: evidence for progressive break up of an Archean supercontinent.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.Northwest TerritoriesDyke, Supercontinent
DS1994-1235
1994
van Breemen, O.Morin, D., Corriveau, L., Tellier, M., van Breemen, O.A 1070 Ma ultrapotassic breccia dyke in the Central metasedimentary belt ofQuebec.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. posterQuebecDyke, Ultrapotassic
DS1994-1860
1994
Van Breemen, O.Villeneuve, M.E., Van Breemen, O.A compilation of uranium-lead (U-Pb) age dat a from the Slave ProvinceGeological Survey of Canada Open file, No. 2972, 53p.Northwest TerritoriesGeochronology, Slave Province
DS1995-1076
1995
Van Breemen, O.LeCheminant, A.N., Van Breemen, O., Buchan, K.L.Proterozoic dyke swarms Lac de Gras Aylmer Lake area: regional distribution ages and PaleomagnetismGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Annual Meeting Abstracts, Vol. 20, p. A57 AbstractNorthwest TerritoriesPaleomagnetics, Dyke swarms
DS1996-0318
1996
Van Breemen, O.Currie, K.L., Van Breemen, O.The origin of rare minerals in the Kipawa syenite complex, western QuebecCanadian Mineralogist, Vol. 34, pt. 2, April pp. 435-452.QuebecAlkaline, carbonatite, Deposit -Kipawa
DS1996-0341
1996
Van Breemen, O.Davis, W.J., Gariepy, C., Van Breemen, O.lead isotopic composition of late Archean granites and the extent of recycling early Archean crust Slave ProvinceChemical Geology, Vol. 130, pp. 255-269Northwest TerritoriesGeochronology, Point Lake, Contwoyto Lake, Slave Province
DS1996-0628
1996
Van Breemen, O.Higgins, M.D., Van Breemen, O.Three generations of AMCG magmatism contact metamorphism and tectonism in Saguenay Lac Saint JeanPrecambrian Research, Vol. 79, pp. 327-46.QuebecGeochronology
DS1996-0823
1996
Van Breemen, O.LeCheminant, A.N., Heaman, L.M., Van Breemen, O., et al.Mafic magmatism, mantle roots and kimberlites in the Slave CratonGeological Survey of Canada, LeCheminant ed, OF 3228, pp. 161-169.Northwest TerritoriesCraton - dykes, plumes, rifting, Mackenzie Dyke swarm
DS1996-1093
1996
Van Breemen, O.Pehrsson, S., Hanmer, S., Van Breemen, O.uranium-lead (U-Pb) geochronology of the Raglan gabbro belt: implications for an ensialic marginal basin GrenvilleCanadian Journal of Earth Sciences, Vol. 33, pp. 691-702.Quebec, Labrador, UngavaGeochronology, Orogeny - Grenville
DS1999-0068
1999
Van Breemen, O.Bingen, B., Demaiffe, D., Van Breemen, O.The 616 Ma old Egersund basaltic dike swarm and late Neoproterozoic opening of the Iapetus Ocean.Journal of Geology, Vol. 106, No. 5, Sept. pp. 565-74.Norway, Labrador, QuebecTectonics, Dikes, Long Range
DS2002-1254
2002
Van Breemen, O.Peterson, T.D., Van Breemen, O., Sandeman, H., Cousens, B.Proterozoic (1.85-1.75 Ga) igneous suites of the Western Churchill Province: granitoidPrecambrian Research, Vol. 119, No. 1-4, pp. 73-100.Alberta, Northwest TerritoriesMagmatism - tectonics, Minettes, Trans Hudson
DS200612-0422
2005
Van Breemen, O.Gandhi, S.S., Van Breemen, O.SHRIMP U Pb geochronology of detrital zircons from the Treasure Lake Group - new evidence for Paleoproterozoic collisional tectonics in the southern Hottah terrane.Canadian Journal of Earth Sciences, Vol. 42, 5, pp. 833-845.Canada, Northwest TerritoriesGeochronology - not specific to diamonds
DS200912-0080
2009
Van Breemen, O.Buchan, K.L., LeCheminant, A.N., Van Breemen, O.Paleomagnetism and U-Pb geochronology of the Lac de Gras diabase dyke swarm, Slave Province Canada: implications for relative drift of Slave and Superior provinces in the Paleoproterozoic.Canadian Journal of Earth Sciences, Vol. 46, pp. 361-379.Canada, Northwest TerritoriesGeophysics
DS2003-1055
2003
Van BreenenPehrsson, S.J., Peterson, T., Davis, W.J., Sandeman, Skulski, Van BreenenAncient Archean crust in the Western Churchill Province: a review of direct and indirect31st Yellowknife Geoscience Forum, p. 75. (abst.)Saskatchewan, Manitoba, NunavutTectonics - lithosphere
DS2003-1056
2003
Van BreenenPehrsson, S.J., Peterson, T., Davis, W.J., Sandeman, Skulski, Van BreenenThe Western Churchill metallogeny project: from Melville to Uranium City, a new look31st Yellowknife Geoscience Forum, p. 77. (abst.)Saskatchewan, Manitoba, Nunavut, Northwest TerritoriesBedrock compilation
DS200412-1515
2003
Van BreenenPehrsson, S.J., Peterson, T., Davis, W.J., Sandeman, Skulski, Van Breenen, Hartlaub, Wodicks, Hanmer, CousensAncient Archean crust in the Western Churchill Province: a review of direct and indirect evidence.31st Yellowknife Geoscience Forum, p. 75. (abst.)Canada, Saskatchewan, Manitoba, NunavutTectonics - lithosphere
DS200412-1516
2003
Van BreenenPehrsson, S.J., Peterson, T., Davis, W.J., Sandeman, Skulski, Van Breenen, Hartlaub, Wodicks, Hanmer, CousensThe Western Churchill metallogeny project: from Melville to Uranium City, a new look at the largest under explored Craton in the31st Yellowknife Geoscience Forum, p. 77. (abst.)Canada, Saskatchewan, Manitoba, Northwest Territories, NunavutBedrock compilation
DS201212-0288
2012
Van Breugel, B.Harvey, S., Read, G., DesGagnes, B., Shimell, M., Danoczi, J., Van Breugel, B., Fourie, L., Stilling, A.Utilization of olivine macrocryst grain size and abundance dat a as a proxy for diamond size and grade in pyroclastic deposits of the Orion South kimberlite Fort a la Corne, Sasakatchewan, Canada.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, SaskatchewanDeposit - Orion South
DS201412-0344
2013
van Breugel, B.Harvey, S., Read, G., DesGagnes, B., Shimell, M., van Breugel, B., Fourie, L.Utilization of olivine macrocryst grain size and abundance dat a as a proxy for diamond size and grade in pyroclastic deposits of the Orion South kimberlite, Fort a la Corne, Saskatchewan, Canada.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 79-96.Canada, SaskatchewanDeposit - Orion South
DS201412-0135
2014
van Buren, R.Combrink, M., van Buren, R.Shallow alluvial diamond exploration with GENESIS airborne TEMGSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 10-12, POSTERTechnologyGeophysics - GENESIS
DS1975-1232
1979
Van buren, W.Steele, K.F., Jackson, K.C., Van buren, W.Geochemical Comparison of Arkansaw SyeniteGeological Society of America (GSA), Vol. 11, No. 2, P. 166. (abstract.).United States, Gulf Coast, Arkansas, Garland County, Hot Spring CountyMagnet Cove, Potash Sulfur Springs, Geochemistry
DS1986-0349
1986
Van Calsteren, P.Hawkesworth, C.J., Van Calsteren, P., Palacz, Z., Rogers, N.W.Crustal xenoliths from southern Africa: chemical and age variations within the continental crustProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 253-255South Africa, LesothoBlank
DS1987-0282
1987
Van Calsteren, P.Hawkesworth, C.J., Van Calsteren, P., Rogers, N.W., Menzies, M.A.Isotope variations in recent volacnics: a trace element perspectiveIn: Mantle Metasomatism, edited M.A. Menzies, C.J. Hawkesworth, Academic, pp. 365-388GlobalBlank
DS1988-0348
1988
Van Calsteren, P.Kempton, P.D., Hawkesworth, C.J., Van Calsteren, P., Moorbath, S.Evidence for Cenozoic underplating of the lower crust: isotopic andTerra Cognita, Eclogite conference Abstracts, Vol. 8, No. 3, Summer, p. 271. AbstractArizonaMantle, Geronimo
DS1995-0829
1995
Van Calsteren, P.Huang, Y.-M., Van Calsteren, P., Hawkesworth, C.J.The evolution of the lithosphere in southern Africa: a perspective on basic granulite xenoliths - kimberlitesGeochim. Cosmochimica Acta, Vol. 59, No. 23, Dec. 1, pp. 4905-4920.South Africa, BotswanaXenoliths, Kimberlites
DS1982-0265
1982
Van calsteren, P.W.Hawkesworth, C.J., Rogers, N.W., Van calsteren, P.W., Menzies.Neodymium and Strontium Isotope Studies on Crustal Xenoliths from southernafrica.Proceedings of Third International Kimberlite Conference, TERRA, Vol. 2, No. 3, P. 236, (abstract.).South Africa, LesothoKimberlite, Geochronology
DS1980-0237
1980
Van calsteren, P.W.C.Minnigh, L.D., Van calsteren, P.W.C., Den tex, E.Quenching: an Additional Model for Emplacement of the Lherzolite at Lers (french Pyrenees.)Geology, Vol. 8, JANUARY PP. 18-21.GlobalGeology
DS1984-0349
1984
Van calsteren, P.W.C.Hawkesworth, C.J., Rogers, N.W., Van calsteren, P.W.C., Menzies.Mantle Enrichment ProcessesNature., Vol. 311, No. 6984, SEPT. 27TH. PP. 331-335.GlobalBasanite, Kimberlite, Genesis
DS1987-0532
1987
Van Calsteren, P.W.C.Nixon, P.H., Van Calsteren, P.W.C., Boyd, F.R., Hawkesworth, C.J.Harzburgites with garnets of diamond facies from southernAfricankimberlitesin: Nixon, P.H. ed. Mantle xenoliths, J. Wiley, pp. 523-534South Africap. 527 analyses
DS200812-0806
2008
Van Collar, B.Nowicki, T., Hetman, C.J., Gurney, J., Van Collar, B., Galloway, M., Mukodzani, B.Optimizing kimberlite evaluation programs by integrating geological, mineralogical and geophysical data.Northwest Territories Geoscience Office, p. 46-47. abstractTechnologyBrief overview - evaluation
DS2003-1408
2003
Van Coller, B.Van Coller, B., Hildenbrand, P., Verran, D., Barnes, F., Nowicki, T.E.Southern African case studies of variations in indicator mineral characteristics with8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractSouth AfricaBlank
DS2003-1478
2003
Van Coller, B.Williams, C., Van Coller, B., Nowicki, T., Gurney, J.J.Mega Kalahari geology: challenges of kimberlite exploration in this medium8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractSouth Africa, Democratic Republic of CongoKaapvaal Craton
DS200412-2034
2003
Van Coller, B.Van Coller, B., Hildenbrand, P., Verran, D., Barnes, F., Nowicki, T.E., Baumgartner, M., Ott, L., Gurney, J.J.Southern African case studies of variations in indicator mineral characteristics with distance from kimberlite source.8 IKC Program, Session 8, POSTER abstractAfrica, South AfricaDiamond exploration
DS200412-2115
2003
Van Coller, B.Williams, C., Van Coller, B., Nowicki, T., Gurney, J.J.Mega Kalahari geology: challenges of kimberlite exploration in this medium.8 IKC Program, Session 8, POSTER abstractAfrica, South Africa, Democratic Republic of CongoDiamond exploration Kaapvaal Craton
DS200812-0805
2008
Van Coller, B.Nowicki, T., Helman, C., Gurney, J., Van Coller, B., Galloway, M., Smith, C., Mukodzani, B.Optimizing kimberlite evaluation programs by integrating geological, mineralogical and geophysical data.GSSA-SEG Meeting Held July, Johannesburg, 19 Power point slidesTechnologyEvaluation
DS200912-0240
2009
Van Coller, B.Galloway, M., Nowicki, T., Van Coller, B., Mukodzani, B., Siemens, K., Hetman, C., Webb, K., Gurney, J.Constraining kimberlite geology through integration of geophysical, geological and geochemical methods: a case study of the Mothae kimberlite, northern Lesotho.Lithos, In press - available 47p.Africa, LesothoDeposit - Mothae
DS1995-0758
1995
Van Couvering, J.Harris, J., Van Couvering, J.Mick aridity and the paleoecology of volcanically influenced ecosystemsGeology, Vol. 23, No. 7, July pp. 593-596KenyaVolcanicity volcanics, Arid environments
DS1997-1190
1997
Van Couvering, J.Van Couvering, J.Diamond desert memoriesNatural History, Vol. 106, No. 10, Nov. pp. 16-21.NamibiaHistory, Popular article
DS2001-1182
2001
Van De CarVan der Lee, S., Van De Car, Fouch, JamesCombined sensitivity to the Kaapvaal tectosphere of regional and teleseismic surface and S Waves.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractSouth AfricaGeophysics - seismics, Lithosphere
DS200412-0567
2004
Van De Car, J.C.Fouch, M.J., James, D.E., Van De Car, J.C., Van Der Lee, S.Mantle seismic structure beneath the Kaapvaal and Zimbabwe Cratons.South African Journal of Geology, Vol. 107, 1/2, pp. 33-44.Africa, South Africa, ZimbabweGeophysics - seismics, tectonics, magmatism
DS2001-0528
2001
Van De Car, M.J.James, D.E., Fouch, D.J., Van De Car, M.J., VanderleeTectosphere structure beneath southern AfricaGeophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2485-88.South AfricaTectonics
DS1975-0751
1978
Van De Graaff, W.J.E.Van De Graaff, W.J.E., Crowe, R.W.A., Bunting, J.A., Jackson, M.Relic Early Cainozoic Drainages in Arid Western AustraliaZeitschr. Geomorph., Vol. 21, No. 4, PP. 379-400.Australia, Western AustraliaDiamond, Geomorphology
DS201805-0986
2018
van de Locht, J.van de Locht, J., Hoffmann, J.E., Li, C., Wang, Z., Becker, H., Rosing, M.T., Kleinschrodt, R., Munker, C.Earth's oldest mantle peridotites show entire record of late accretion.Geology, Vol. 46, 3, pp. 199-202.Europe, Greenlandperidotites

Abstract: An important issue in Earth’s earliest history is the timing and mixing history of the late accreted material that supplied highly siderophile elements to Earth’s mantle after core segregation. Previously, constraints on ancient mantle processes could only be obtained indirectly from mantle-derived magmas such as basalts or komatiites. Relics of Eoarchean (older than 3.8 Ga) mantle were proposed to occur within the Eoarchean terrains of western Greenland. Here we provide geochemical evidence, including combined platinum group element (PGE) and Re-Os isotope data, showing that modern mantle-like peridotites occur at two localities in southwest Greenland. Rhenium-depletion model ages of these peridotites are mostly of Eoarchean age, in accord with U-Pb zircon ages of crosscutting granitoid intrusives. PGE abundances and patterns are similar to those of modern depleted mantle peridotites. For the first time, such patterns provide conclusive evidence for preservation of Eoarchean depleted mantle rocks that are clearly distinguishable from magmatic cumulates or komatiites. Abundances of Os, Ir, and Ru combined with Os isotope compositions in the Greenland peridotites reveal that primitive late accreted material appears to have been efficiently mixed into the sampled mantle domains by Eoarchean time.
DS201602-0229
2016
van de Moortele, B.Perrillat, J.P., Chollet, M., Durand, S., van de Moortele, B., Chambat, F., Mezouar, M., Daniel, I.Kinetics of the olivine-ring woodite transformation and seismic attentuation in the Earth's mantle transition zone.Earth and Planetary Science Letters, Vol. 433, pp. 360-369.MantleGeophysics - seismics

Abstract: In regions of the mantle where multi-phases coexist like at the olivine-wadsleyite-ringwoodite transitions, the stress induced by the seismic waves may drive a mineralogical reaction between the low to high pressure phases, a possible source of dissipation. In such a situation, the amount of attenuation critically depends on the timescale for the phase transformations to reach equilibrium relative to the period of the seismic wave. Here we report synchrotron-based measurements of the kinetics of the olivine to ringwoodite transformation at pressure-temperature conditions of the co-stability loop, for iron-rich olivine compositions. Both microstructural and kinetic data suggest that the transformation rates are controlled by growth processes after the early saturation of nucleation sites along olivine grain boundaries. Transformation-time data show an increase of reaction rates with temperature and iron content, and have been fitted to a rate equation for interface-controlled transformation: G=k0?T?exp?[n?XFa]?exp?[?(?Ha+PV?)/RT]×[1?exp?(?Gr/RT)]G=k0?T?exp?[n?XFa]?exp?[?(?Ha+PV?)/RT]×[1?exp?(?Gr/RT)], where XFaXFa is the fayalite fraction, the exponential factor n=9.7n=9.7, View the MathML sourceln?k0=?9.1 ms?1. View the MathML sourceXFa?1 and ?Ha=199 kJ/mol?Ha=199 kJ/mol, assuming V?=0 cm3/molV?=0 cm3/mol. Including these new kinetic results in a micro-mechanical model of a two-phase loop (Ricard et al., 2009), we predict View the MathML sourceQK?1 and View the MathML sourceQ??1 significantly higher than the PREM values for both body waves and normal modes. This attests that the olivine-wadsleyite transition can significantly contribute to the attenuation of the Earth's mantle transition zone.
DS1996-1436
1996
Van de VooTorsvik, T.H., Smethurst, M.A., Meert, J.G., Van de VooContinental breakup and collision in the Neoproterozoic and Paleozoic - atale of Baltica and Laurentia.Earth Science Reviews, Vol. 40, pp. 229-258.Baltica, Laurentia, Rodinia, PangeaSupercontinent, Tectonics
DS2001-1180
2001
Van de Zedde, D.M.A.Van de Zedde, D.M.A., Wortel, M.J.R.Shallow slab detachment as a transient source of heat at midlithospheric depthsTectonics, Vol. 20, No. 6, Dec. pp. 868-82.MantleSlab, breakoff, Subduction
DS2002-1523
2002
Van Decan, J.C.Sol, S., Thomson, C.J., Kendall, J.M., White, D., Van Decan, J.C., Asudeh, I.Seismic tomographic images of the cratonic upper mantle beneath the Western SuperiorPhysics of the Earth and Planetary Letters, Vol. 134, 1-2, pp. 53-69.Manitoba, Saskatchewan, Alberta, Northwest TerritoriesGeophysics - seismics, subduction
DS1998-1240
1998
Van Decar, J.C.Ritsema, J., Nyblade, A.A., Van Decar, J.C.Upper mantle seismic velocity structure beneath Tanzania, implications For the stability of cratonic..Journal of Geophysical Research, Vol. 103, No. 9, Sept. 10, pp. 21, 201-14.Tanzania, East AfricaGeophysics - seismics, Craton, lithosphere
DS200612-0124
2006
Van Decar, J.C.Benoit, M.H., Nyblade, A.A., Van Decar, J.C.Upper mantle P wave speed variations beneath Ethiopia and the origin of the Afar hotspot.Geology, Vol. 34, 5, pp. 329-332.Africa, EthiopiaGeophysics - seismic, plume
DS200712-0188
2007
Van den Berg, A.Cizkova, H., Van Hunden, J., Van den Berg, A.Stress distribution within subducting slabs and their deformation in the transition zone.Physics of the Earth and Planetary Interiors, Vol. 161, 3-4, pp. 202-214.MantleSubduction
DS1993-1640
1993
Van den Berg, A.P.Van den Berg, A.P., et al.High melting temperature of perovskite: dynamical implications for creep In the lower mantle.American Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 557.MantlePerovskite, Petrology
DS1994-1864
1994
Van den Berg, A.P.Vlaar, N.J., Van Keken, .E., Van den Berg, A.P.Cooling of the Earth in the Archean: consequences of pressure release melting in a hotter mantleEarth and Planetary Science Letters, Vol. 121, No. 1-2, January pp. 1-18MantleArchean, Melting
DS1994-1865
1994
Van den Berg, A.P.Vlaar, N.J., Van Keken, P.E., Van den Berg, A.P.Cooling of the earth in thr Archean: consequences of pressure release melting in a hotter mantle.Earth and Planetary Science Letters, Vol. 121, No. 1/2, January pp. 1-18.MantleArchean, Hot spots
DS1998-0197
1998
Van den Berg, A.P.Cadek, O., Van den Berg, A.P.Radial profiles of temperature and viscosity in the Earth's mantle inferred from the geoid and lateral seismic structure.Earth and Planetary Science Letters, Vol. 164, No.4, Dec.30. pp. 607-616.MantleGeophysics - seismics, tomography
DS1998-0325
1998
Van den Berg, A.P.De Smet, J.H., Van den Berg, A.P., Vlaar, N.J.Stability and growth of continental shields in mantle convection models including recurrent melt production.Tectonophysics, Vol. 296, No. 1-2, . Oct. 30, pp. 15-30.MantleCraton, Magmatism
DS1999-0161
1999
Van Den Berg, A.P.De Smet, J.H., Van Den Berg, A.P., Vlaar, N.J.The evolution of continental roots in numerical thermo-chemical mantle convection models including ...Lithos, Vol. 48, No. 1-4, Sept. pp. 153-70.MantleGeothermometry - model, Melting - differentiation of partial
DS2000-0216
2000
Van den Berg, A.P.De Smet, J., Van den Berg, A.P., Vlaar, N.J.Early formation and long term stability of continents resulting from decompression melting convecting mantle.Tectonophysics, Vol. 322, No. 1-2, pp. 19-33.MantleMagmatism - convection
DS2000-0217
2000
Van den Berg, A.P.De Smet, J., Van den Berg, A.P., Vlaar, N.J.Early formation and long term stability of continents resulting decompression melting in convecting mantle.Tectonophysics, Vol.322, No.1-2, July10, pp.19-34.MantleMagmatism, Convection
DS2002-1637
2002
Van den Berg, A.P.Van den Berg, A.P., Yuen, D.A., Allwardt, J.R.Non linear effects from variable thermal conductivity and mantle internal heating: implications for melting..Physics of the Earth and Planetary Interiors, Vol.129, 3-4, pp.359-75.MantleMelting - massive and secular cooling
DS2002-1644
2002
Van den Berg, A.P.Van Hunen, J., Van den Berg, A.P., Vlaar, N.J.The impact of the South American plate motion and the Nazca Ridge subduction on the flat subduction below south Peru.Geophysical Research Letters, Vol. 29, 14, DOI 10.1029/2001GL014004PeruTectonics - subduction
DS200512-1115
2005
Van den Berg, A.P.Van den Berg, A.P., Rainey, E.S., Yuen, D.A.The combined influence of variable thermal conductivity, temperature and pressure dependent viscosity and core mantle coupling on thermal evolutionPhysics of the Earth and Planetary Interiors, Vol. 149, 3-4, pp. 259-278.MantleGeothermometry
DS200512-1116
2005
Van den Berg, A.P.Van den Berg, A.P., Rainey, E.S.G., Yuen, D.A.Dependent viscosity and core mantle coupling on thermal evolution.Physics of the Earth and Planetary Interiors, Vol. 149, 3-4, April 15, pp. 259-278.MantleGeothermometry
DS200512-1120
2004
Van den Berg, A.P.Van Hunen, J., Van den Berg, A.P., Vlaar, N.J.Various mechanisms to induce present day shallow flat subduction and implications for the younger Earth: a numerical parameter study.Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 159-194.MantleSubduction
DS200512-1124
2004
Van den Berg, A.P.Van Thiemen, P., Van den Berg, A.P., Vlaar, N.J.On the formation of continental silicic melts in thermochemical mantle convection models: implications for early Earth.Tectonophysics, Vol. 394, 1-2, pp. 111-138.MantleGeothermometry
DS200812-1203
2008
Van den Berg, A.P.Van Hunen, J., Van den Berg, A.P.Plate tectonics on the Early Earth: limitations imposed by strength and bouyancy of subducted lithosphere.Lithos, Vol. 103, 1-2, pp. 217-235.MantleTectonics
DS201412-0939
2014
Van den Berg, A.P.Van den Berg, A.P., Yuen, D.A.Is the lower mantle rheology Newtonian today?Geophysical Research Letters, Vol. 23, 16, pp. 2033-20136.MantleRheology
DS2002-1638
2002
Van den Berg, E.H.Van den Berg, E.H., Meetsers, Kenter, SchlagerAutomated separation of touching grains in digital images of thin sectionsComputers and Geosciences, Vol. 28, No. 2, Feb. pp. 179-90.GlobalComputers, Thin sections - not specific to diamonds
DS2003-1410
2003
Van den Berg, P.M.Van der Kruk, J., Wapenaar, C.P.A., Fokkema, J.T., Van den Berg, P.M.Three dimensional imaging of multicomponent ground penetrating radar dataGeophysics, Vol. 68, 4, pp. 1241-54.GlobalGeophysics - radar not specific to diamonds
DS200412-2036
2003
Van den Berg, P.M.Van der Kruk, J., Wapenaar, C.P.A., Fokkema, J.T., Van den Berg, P.M.Three dimensional imaging of multicomponent ground penetrating radar data.Geophysics, Vol. 68, 4, pp. 1241-54.TechnologyGeophysics - radar not specific to diamonds
DS1990-1494
1990
Van den Beukel, J.Van den Beukel, J.Breakup of young oceanic lithosphere in the upper part of a subductionzone: implications for the emplacement of ophiolitesTectonics, Vol. 9, No. 4, August pp. 825-844GlobalOphiolite, Tectonics
DS1990-1495
1990
Van Den Beukel, P.J.Van Den Beukel, P.J.Thermal and mechanical modelling of convergent plate marginsGeol. Ultraiectina, University of Utrech, Institute of Earth Sciences, The, No. 62, 126pGlobalOphiolites, Plate Tectonics, Table of contents only
DS2002-0730
2002
Van den Bogaard, P.Hoernle, K., Van den Bogaard, P., Werner, R., Lissinaa, B., Hauff, F., AlvaradoMissing history ( 16 -71 Ma) of the Galapagos hotspot: implications for the tectonicGeology, Vol. 30, 9, Sept. pp. 795-98.United StatesTectonics
DS200812-0392
2008
Van den Bogaard, P.Geldmacher, J., Hoernle, K., Lgel, A., Van den Bogaard, P., Bindeman, I.Geochemistry of a new enriched mantle type locality in the northern hemisphere: implications for the origin of the EM-I source.Earth and Planetary Science Letters, Vol. 265, 1-2, pp. 167-182.MantleGeophysics - EM
DS200812-0420
2007
Van den Bogaard, P.Goldmacher, J., Hoernle, K., Klugel, A., Van den Bogaard, P., Bindeman, I.Geochemistry of a new enriched mantle type locality in the northern hemisphere: implications for the origin of the EM-I source.Earth and Planetary Science Letters, Vol. 265, 1-2, pp. 167-182.MantleMetasomatism
DS201012-0598
2010
Van den Bogaard, P.Prelevic, D., Akal, C., Foley, S.F., Romer, R.L., Stracke, A., Van den Bogaard,P.Post collisional mantle dynamics of an orogenic lithosphere: lamproitic mafic rocks from SW Anatolia, Turkey.Geological Society of America Abstracts, 1p.Europe, TurkeyLamproite
DS201112-0824
2011
Van den Bogaard, P.Prelevic, D., Akal, C., Foley, S.F., Romer, R.R.,Stracke, A., Van den Bogaard, P.Ultrapotassic mafic rocks as geochemical proxies for post collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, TurkeyAlkalic
DS201112-0825
2011
Van den Bogaard, P.Prelevic, D., Akal, C., Romer, R.R., Sracke, A., Van den Bogaard, P.Ultrapotassic mafic rocks as geochemical proxies for post collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.119-121.Europe, TurkeyLamproite
DS201112-0826
2011
Van den Bogaard, P.Prelevic, D., Akal, C., Romer, R.R., Sracke, A., Van den Bogaard, P.Ultrapotassic mafic rocks as geochemical proxies for post collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.119-121.Europe, TurkeyLamproite
DS201312-0485
2013
Van den Bogaard, P.Kipl, A.F., Werner, R., Gohl, K., Van den Bogaard, P., Hoemle, K., Maichur, D., Klugel, A.Seamounts off the West Antarctic margin: a case for non-hotpsot driven intra-plate volcanism.Gondwana Research, Vol. 25, 4, pp. 1660-1679.AntarcticaIntra-plate volcanism
DS201512-1976
2016
van den Bogaard, P.Tappe, S., Smart, K.A., Stracke, A., Romer, R.L., Prelevic, D., van den Bogaard, P.Melt evolution beneath a rifted carton edge: 40Ar/39/Ar geochronology and Sr-Nd-Hf-Pb isotope systematics of primitive alkaline basalts and lamprophyres from the SW Baltic Shield.Geochimica et Cosmochimica Acta, Vol. 173, pp. 1-36.Europe, SwedenAlkalic
DS201602-0244
2016
van den Bogaard, P.Tappe, S., Smart, K.A., Stracke, A., Romer, R.L., Prelevic, D., van den Bogaard, P.Melt evolution beneath a rifted craton edge: 40Ar/39Ar geochronology and Sr-Nd-Hf-Pb isotope systematics of primitive alkaline basalts and lamprophyres from the SW Baltic shield.Geochimica et Cosmochimica Acta, Vol. 173, pp. 1-36.EuropeGeochronology

Abstract: A new high-precision 40Ar/39Ar anorthoclase feldspar age of 176.7 ± 0.5 Ma (2-sigma) reveals that small-volume alkaline basaltic magmatism occurred at the rifted SW margin of the Baltic Shield in Scania (southern Sweden), at a time of global plate reorganization associated with the inception of Pangea supercontinent break-up. Our combined elemental and Sr-Nd-Hf-Pb isotope dataset for representative basanite and nephelinite samples (>8 wt.% MgO) from 16 subvolcanic necks of the 30 by 40 km large Jurassic volcanic field suggests magma derivation from a moderately depleted mantle source (87Sr/86Sri = 0.7034-0.7048; ?Ndi = +4.4 to +5.2; ?Hfi = +4.7 to +8.1; 206Pb/204Pbi = 18.8-19.5). The mafic alkaline melts segregated from mixed peridotite-pyroxenite mantle with a potential temperature of ?1400 °C at 2.7-4.2 GPa (?90-120 km depths), which places ultimate melt generation within the convecting upper mantle, provided that the lithosphere-asthenosphere boundary beneath the southern Baltic Shield margin was at ?100 km depth during Mesozoic-Cenozoic rifting. Isotopic shifts and incompatible element enrichment relative to Depleted Mantle reflect involvement of at least 20% recycled oceanic lithosphere component (i.e., pyroxenite) with some minor continent-derived sediment during partial melting of well-stirred convecting upper mantle peridotite. Although pargasitic amphibole-rich metasomatized lithospheric mantle is excluded as the main source of the Jurassic magmas from Scania, hydrous ultramafic veins (i.e., hornblendite) may have caused subtle modifications to the compositions of passing sublithospheric melts. For example, modeling suggests that the more radiogenic Hf (?Hfi = +6.3 to +8.1) and Pb (206Pb/204Pbi = 18.9-19.5) isotopic compositions of the more sodic and H2O-rich nephelinites, compared with relatively homogenous basanites (?Hfi = +4.7 to +6.1; 206Pb/204Pbi = 18.8-18.9), originate from minor interactions between rising asthenospheric melts and amphibole-rich metasomatic components. The metasomatic components were likely introduced to the lithospheric mantle beneath the southern Baltic Shield margin during extensive Permo-Carboniferous magmatic activity, a scenario that is supported by the geochemical and isotope compositions of ca. 286 Ma lamprophyres from Scania (87Sr/86Sri = 0.7040-0.7054; ?Ndi = +2.0 to +3.1; ?Hfi = +6.1 to +9.0; 206Pb/204Pbi = 17.8-18.2). Strong variations in lithosphere thickness and thermal structure across the southern Baltic Shield margin may have caused transient small-scale mantle convection. This resulted in relatively fast and focused upwellings and lateral flow beneath the thinned lithosphere, where mafic alkaline magmas formed by low degrees of decompression melting of sublithospheric mantle. Such a geodynamic scenario would allow for enriched recycled components with low melting points to be preferentially sampled from the more depleted and refractory convecting upper mantle when channeled along a destabilizing craton edge. Similar to the ‘lid effect’ in oceanic island volcanic provinces, lithospheric architecture may exert strong control on the mantle melting regime, and thus offer a simple explanation for the geochemical resemblance of continental and oceanic intraplate mafic alkaline magmas of high Na/K affinity.
DS1975-0883
1978
Van den bosch, L.W.P.Van den bosch, L.W.P.Time to Marshall All South Africa's Economic ResourcesSth. Afr. Min. Surv., No. 89, PP. 2-14.South AfricaDiamonds, Resources
DS202008-1453
2020
van den Broeck, J.M.van den Broeck, J.M., Gaina, C.Microcontinents and continental fragments associated with subduction systems.Tectonics, in press available, e2020TC006063 39p. PdfGlobalsubduction

Abstract: Microcontinents and continental fragments are small pieces of continental crust that are surrounded by oceanic lithosphere. Although classically associated with passive margin formation, here we present several preserved microcontinents and continental fragments associated with subduction systems. They are located in the Coral Sea, South China Sea, central Mediterranean and Scotia Sea regions and a ‘proto?microcontinent’, in the Gulf of California. Reviewing the tectonic history of each region and interpreting a variety of geophysical data allows us to identify parameters controlling the formation of microcontinents and continental fragments in subduction settings. All these tectonic blocks experienced long, complex tectonic histories with an important role for developing inherited structures. They tend to form in back?arc locations and separate from their parent continent by oblique or rotational kinematics. The separated continental pieces and associated marginal basins are generally small and formation is quick (<50 Myr). Microcontinents and continental fragments formed close to large continental masses tend to form faster than those created in systems bordered by large oceanic plates. A common triggering mechanism for formation is difficult to identify, but seems to be linked with rapid changes of complex subduction dynamics. The young ages of all contemporary pieces found in situ suggest that microcontinents and continental fragments in these settings are short lived. Although presently the amount of in?situ subduction?related microcontinents is meagre (an area of 0.56% and 0.28% of global, non?cratonic, continental crustal area and crustal volume respectively), through time microcontinents contributed to terrane amalgamation and larger continent formation.
DS202009-1672
2020
van den Broek, J.M.van den Broek, J.M., Gaina, C.Microcontinents and continental fragments associated with subduction systems.Tectonics, 10.1029/2020/TC006063 29p. PdfGlobalsubduction

Abstract: Microcontinents and continental fragments are small pieces of continental crust that are surrounded by oceanic lithosphere. Although classically associated with passive margin formation, here we present several preserved microcontinents and continental fragments associated with subduction systems. They are located in the Coral Sea, South China Sea, central Mediterranean and Scotia Sea regions, and a “proto?microcontinent,” in the Gulf of California. Reviewing the tectonic history of each region and interpreting a variety of geophysical data allows us to identify parameters controlling the formation of microcontinents and continental fragments in subduction settings. All these tectonic blocks experienced long, complex tectonic histories with an important role for developing inherited structures. They tend to form in back?arc locations and separate from their parent continent by oblique or rotational kinematics. The separated continental pieces and associated marginal basins are generally small and their formation is quick (<50 Myr). Microcontinents and continental fragments formed close to large continental masses tend to form faster than those created in systems bordered by large oceanic plates. A common triggering mechanism for their formation is difficult to identify, but seems to be linked with rapid changes of complex subduction dynamics. The young ages of all contemporary pieces found in situ suggest that microcontinents and continental fragments in these settings are short lived. Although presently the amount of in?situ subduction?related microcontinents is meager (an area of 0.56% and 0.28% of global, non?cratonic, continental crustal area and crustal volume, respectively), through time microcontinents contributed to terrane amalgamation and larger continent formation.
DS201705-0885
2017
van den Heuvel, Q.van den Heuvel, Q., Matveev, S., Drury, M., Gress, M., Chinn, I., Davies, G.Genesis of diamond inclusions: an integrated cathodluminescence ( CL) and electron backscatter diffraction (EBSD) study on eclogitic and peridotitic inclusions and their diamond host.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 6564 AbstractAfrica, BotswanaDeposit - Jwaneng, Letlhakane
DS201810-2308
2018
van den Heuvel, Q.Davies, G.R., van den Heuvel, Q., Matveev, S., Drury, M.R., Chinn, I.L., Gress, M.U.A combined catholuminescence and electron backscatter diffraction examination of the growth relationships between Jwaneng diamonds and their eclogitic inclusions.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0634-3 12p.Africa, Botswanadeposit - Jwaneng

Abstract: To fully understand the implications of the compositional information recorded by inclusions in diamond it is vital to know if their growth was syn- or protogenetic and the extent to which they have equilibrated with diamond forming agents. The current paradigm is that the majority of inclusions in diamond are syngenetic but recently this assumption has been questioned. This study presents an integrated cathodoluminescence (CL) and electron backscatter diffraction (EBSD) study of 8 diamonds containing eclogitic inclusions: 19 pyrope-almandine garnets, 12 omphacitic clinopyroxenes, 4 sulphides, 1 coesite and 1 rutile from the Jwaneng diamond mine, Botswana. Diamond plates were sequentially polished to expose inclusions at different levels and CL imaging and EBSD were performed to constrain the relationship between diamond and inclusion growth. Despite complex growth and resorption, individual diamonds are single crystals with a homogeneous crystallographic orientation. All individual inclusions have homogeneous crystallographic orientation and no resolvable compositional zonation. The combined CL and EBSD data suggest that epitaxial inclusion-diamond growth is rare (none of 24 inclusions) and that the imposition of cubo-octahedral faces on inclusions does not necessarily result in epitaxy. Individual diamonds contain inclusions that record evidence of both syngentic and protogenetic relationships with the host diamond and in one case an inclusion appears syngenetic to the diamond core but protogenetic to the growth zone that surrounds 70% of the inclusion. These findings emphasise that inclusions in diamonds have multiple modes of origin and that in order to validate the significance of geochronological studies, further work is needed to establish that there is rapid chemical equilibration of protogenetic inclusions with diamond forming agents at mantle temperatures.
DS1989-1371
1989
Van Den Hul, H.J.Sengupta, S., Acharyya, S.K., Van Den Hul, H.J., Chattopadhyay, B.Geochemistry of volcanic rocks from the Naga Hillsophiolites,northeast India and their inferred tectonic settingJournal of the Geological Society of London, Vol. 146, No. 3, May pp. 491-498IndiaHarzburgite, Tectonics
DS200512-1234
2005
Van den Kerkhof, A.M.Zeming, Z., Kun, S., Van den Kerkhof, A.M., Hoefs, J., Liou, J.G.Fluid composition and evolution attending UHP metamorphism: study of fluid inclusions from drill cores, southern Sulu Belt, eastern China.International Geology Review, Vol. 47, 3, pp. 297-309.ChinaUHP
DS2002-1746
2002
Van den Kerkof, A.M.Xiao, Y., Hoefs, J., Van den Kerkof, A.M., Simon, K., Fiebig, J., Zheng, Y.F.Fluid evolution in the Baia Mare epithermal gold/polymetallic district, Inner Carpathians, RomaniaJournal of Petrology, Vol. 43, No. 8, pp. 1505-28.ChinaGeochemistry, UHP
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Van denberg, A.P.Czkova, H., Van Hunen, J., Van denberg, A.P., Vlaar, N.J.The influence of rheological weakening and yield stress on the interaction of slabs with the 670 km discontinuity.Earth and Planetary Science Letters, Vol.199,3-4,pp.447-57.MantleBoundary, Subduction
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Van denberg, A.P.Van denberg, A.P., Yuen, D.A.Delayed cooling of the Earth's mantle due to variable thermal conductivity and the formation of low conductivity zone.Earth and Planetary Science Letters, Vol.199,3-4,pp.403-13.MantleGeophysics - conductivity
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Van der al, D.Van der al, D.Deformation processes in mantle peridotites: with emphasis on the Rondaperidotite of southwest Spain.Utrecht Geologisch Institut der Rijksuniversiteit, 180p.GlobalPeridotite
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Van der Beek, P.Van der Beek, P., Andriessen, ClotinghMorphotectonic evolution of rifted continental margins: inferences from acoupled tectonic surface processes model and fission track thermochronology.Tectonics, Vol. 14, No. 2, Apr. pp. 406-21.MantleTectonics - rifting
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Van der Beek, P.Van der Beek, P., Andriessen, P., Cloetingh, S.Morphotectonic evolution of fluid continental margins: inferences from acoupled tectonic surface processes...Tectonics, Vol. 14, No. 2, Apr. pp. 406-21.GlobalTectonics - model, Thermochronology
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Van der Beek, P.Rohrman, M., Van der Beek, P.Cenozoic postrift domal uplift of North Atlantic margins: an asthenopheric diapirism model.Geology, Vol. 24, No. 10, Oct. pp. 901-904.Norway, United KingdomTectonics - rifting, Diapirs
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Van der Beek, P.Braun, J., Van der Beek, P., Batt, G.Quantitative thermochronology. Numerical methods for the interpretation of thermochronologic data. Case studies, review of isotopic ages.cambridge.org/us/earth, 232p. $ 100.00 ISBN 10-0521830575TechnologyBook - geochronology, geothermometry
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Van der Beek, P.A.Jelsma, H.A., Van der Beek, P.A., Vinyu, M.L.Tectonic evolution of the Bindura-Shamva greenstone belt (northernZimbabwe): progressive deformation around diapiric batholithsJournal of Structural Geology, Vol. 15, No. 2, pp. 165-176ZimbabweStructure, Greenstone belt
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Van der Beek, P.A.Rohrman, M., Van der Beek, P.A., Van der Hilst, R.D., Reemst, P.Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantleGeological Society of London, Special Publication, No. 196, pp. 27-44.MantlePlumes
DS200412-1681
2003
Van der Beek, P.A.Rohrman, M., Van der Beek, P.A., Van der Hilst, R.D., Reemst, P.Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantle upwelling.Geological Society of London, Special Publication, No. 196, pp. 27-44.MantlePlume
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Van der Berg, A.P.Van der Berg, A.P.Early formation and longterm stability of continents resulting from convection and pressure release meltingGeological Society of America (GSA) Annual Meeting, abstract. only, p.A208.MantleCraton, Peridotite
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Van der Berg, A.P.Van der Berg, A.P., Yuen, D.A., Steinbach, V.The effects of variable thermal conductivity on mantle heat transferGeophysical Research Letters, Vol. 28, No. 5, Mar. 1, pp. 875-8.MantleGeothermometry
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Van der Bogert, C.H.Van der Bogert, C.H., Smith, C.P., Hainschwang, T., McClure, S.F.Gray to blue to violet hydrogen rich diamonds from the Argyle mine, Australia.Gems & Gemology, Vol. 45, 1, Spring pp. 20-37.AustraliaDeposit - Argyle, diamond mineralogy
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2003
Van der Hagaeghe, O.Van der Hagaeghe, O., Medvedev, S., Fullsack, P., Beaumont, C., Jamieson, R.A.Evolution of orogenic wedges and continental plateaux: insights from crustalGeophysical Journal International, Vol. 153, 1, pp. 27-51.MantleGeothermometry, Subduction
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Van der Hagaeghe, O.Van der Hagaeghe, O., Medvedev, S., Fullsack, P., Beaumont, C., Jamieson, R.A.Evolution of orogenic wedges and continental plateaux: insights from crustal thermalmechanical models overlying subducting mantlGeophysical Journal International, Vol. 153,1, pp. 27-51.MantleGeothermometry Subduction
DS1991-1776
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Van der Hilst, R.Van der Hilst, R., Engdahl, R., Spakman, W., Nolet, G.Tomographic imaging of subducted lithosphere below northwest Pacific islandarcsNature, Vol. 353, Septe. 5, pp. 37-43Pacific IslandsMantle, Tectonics
DS1994-1824
1994
Van der Hilst, R.Van der Hilst, R., Kennett, B., Ziehuis, A.SKIPPY: a broad band study of seismic structure of the lithosphere And upper mantle below Australia.Geological Society of Australia Abstracts, No. 37, p. 442.AustraliaGeophysics -seismics, Program -SKIPPY
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1994
Van der Hilst, R.Van der Hilst, R., Kennettm B., Christie, D., Grant, J.Project Skippy explores the lithosphere and mantle beneath AustraliaEos, Vol. 75, No. 15, April 12, pp. 177, 180, 181AustraliaMantle, Geophysics -seismics
DS1994-1826
1994
Van der Hilst, R.Van der Hilst, R., Mann, P.Tectonic implications of tomographic images of subducted lithosphere beneath northwestern South AmericaGeology, Vol. 22, No. 5, May pp. 451-454Venezuela, Colombia, South America, ChileTectonics, Slab subduction
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1995
Van der Hilst, R.Van der Hilst, R.Complex morphology of subducted lithosphere in the mantle beneath the Tongatrench.Nature, Vol. 374, No. 6518, March 9, pp. 154-157.MantleSubduction, Tonga Trench
DS200712-0892
2007
Van der Hilst, R.Ribe, N.M., Stutzmann, E., Ren, Y., Van der Hilst, R.Bucking instabilities of subducted lithosphere beneath the transition zone.Earth and Planetary Science Letters, Vol. 254, 1-2, Feb. 15, pp. 173-179.MantleSubduction
DS1997-0437
1997
Van der Hilst, R.D.Grand, S.P., Van der Hilst, R.D., Widiyantoro, S.Global seismic tomography: a snapshot of convection in the earthGsa Today, Vol. 7, No. 4, April pp. 1-7.GlobalTomography, Geophysics - seismics
DS1997-1191
1997
Van der Hilst, R.D.Van der Hilst, R.D., Widiyantoro, S., Engdahl, E.R.Evidence for deep mantle circulation from global tomographyNature, Vol. 386, No. 6625, Apr. 10, pp. 578-586.MantleTomography, Geophysics - seismic
DS1998-1513
1998
Van der Hilst, R.D.Van der Hilst, R.D.Seismological constraints on the fate of slabs and the scale of mantleconvection.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1571-2.MantleGeophysics - seismic tomography, Subduction
DS1998-1514
1998
Van der Hilst, R.D.Van der Hilst, R.D., Kennett, B.L.N., Shibutani, T.Upper mantle structure beneath Australia from portable array deploymentsStructure EVol. Austral., American Geophysical Union (AGU) geodynamics Vol. 26, pp. 39-58.Mantle, AustraliaGeophysics - seismics
DS1999-0218
1999
Van der Hilst, R.D.Fischer, K.M., Van der Hilst, R.D.Geophysics : a seismic look under the continentsScience, Vol. 285, No. 5432, Aug. 27, pp. 1365-6.MantleGeophysics - seismics
DS1999-0671
1999
Van der Hilst, R.D.Simons, F.J., Zielhuis, A., Van der Hilst, R.D.The deep structure of the Australian continent from surface wavetomography.Lithos, Vol. 48, No. 1-4, Sept. pp. 17-44.AustraliaGeophysics - seismics, Tectonics
DS2000-0156
2000
Van der Hilst, R.D.Chevrot, S., Van der Hilst, R.D.The Poisson ratio of the Australian crust: geological and geophysical implications.Earth and Planetary Science Letters, Vol.183, No.1-2, Nov.30, pp.121-32.AustraliaGeophysics - crust
DS2001-0572
2001
Van der Hilst, R.D.Karason, H., Van der Hilst, R.D.Tomographic imaging of the lowermost mantle with differential times of refracted diffracted core phasesJournal of Geophy. Res., Vol. 106, No. 4, Apr. 10, pp. 6569-88.MantleGeophysics - seismics, PKP, Pdiff
DS2001-1104
2001
Van der Hilst, R.D.Soltzer, R.L., Van der Hilst, R.D., Karason, H.Comparing P and S wave heterogeneity in the mantleGeophysical Research Letters, Vol. 28, No. 7, April 1, pp.1335-8.MantleHeterogeneity
DS2002-0016
2002
Van der Hilst, R.D.Albarede, F., Van der Hilst, R.D.Zoned mantle convectionPhilosophical Transactions, Royal Society of London Series A Mathematical, Vol.1800, pp. 2569-92.MantleGeochemistry - model, convection
DS2002-1353
2002
Van der Hilst, R.D.Rogers, R.D., Karason, H., Van der Hilst, R.D.Epeirogenic uplift above a detached slab in northern Central AmericaGeology, Vol. 30, 11, Nov. pp. 1031-4.Nicaragua, Honduras, El Salvador, GuatemalaTectonics - subduction zones ( not specific to diamonds
DS2002-1491
2002
Van der Hilst, R.D.Simons, F.J., Van der Hilst, R.D.Age dependent seismic thickness and mechanical strength of the Australian lithosphereGeophysical Research Letters, Vol. 29, 11, pp. 24- DOI 10.1029/2001GLO14962AustraliaGeophysics - seismics, Tectonics
DS2002-1541
2002
Van der Hilst, R.D.Stankiewicz, J., Chevrot, S., Van der Hilst, R.D., De Wit, M.J.Crustal thickness, discontinuity depth and upper mantle structure beneath southern Africa: constraints from body wave conversions.Physics of the Earth and Planetary Interiors, Vol. 130, No. 3-4, pp. 235-51.South AfricaGeophysics - seismics, Tectonics
DS2003-0225
2003
Van der Hilst, R.D.Castle, J.C., Van der Hilst, R.D.Using ScP precursors to search for mantle structures beneath 1800 km depthGeophysical Research Letters, Vol. 30, 8, 4, 10.1029/2002GLO16023MantleGeophysics - seismics, Discontinuity
DS2003-0226
2003
Van der Hilst, R.D.Castle, J.C., Van der Hilst, R.D.Searching for seismic scattering off mantle interfaces between 800 km and 2000 kmJournal of Geophysical Research, Vol. 108, 2, ESE 13MantleGeophysics - seismics, Lower mantle
DS2003-0779
2003
Van der Hilst, R.D.Lebedev, S., Chevrot, S., Van der Hilst, R.D.Correlation between shear speed structure and thickness of the mantle transition zonePhysics of the Earth and Planetary Interiors, Vol. 136, 1-2, pp. 25-40.MantleBlank
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2003
Van der Hilst, R.D.Rohrman, M., Van der Beek, P.A., Van der Hilst, R.D., Reemst, P.Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantleGeological Society of London, Special Publication, No. 196, pp. 27-44.MantlePlumes
DS2003-1283
2003
Van der Hilst, R.D.Simons, F.J., Van der Hilst, R.D.Seismic and mechanical anisotropy and the past and present deformation of theEarth and Planetary Science Letters, Vol. 211, 3-4, June 30, pp. 271-86.AustraliaGeophysics - seismics, Tectonics, mantle deformation
DS2003-1284
2003
Van der Hilst, R.D.Simons, F.J., Van der Hilst, R.D.Seismic and mechanical anisotropy and the past and present deformation of theEarth and Planetary Science Letters, Vol. 211, 3-4, pp. 271-86.AustraliaTectonics
DS2003-1356
2003
Van der Hilst, R.D.Sze, E.K., Van der Hilst, R.D.Core mantle boundary topography from short period PcP PKP and PKKP dataPhysics of the Earth and Planetary Interiors, Vol. 135, 1, pp. 27-46.MantleGeophysics - seismics
DS200412-0294
2003
Van der Hilst, R.D.Castle, J.C., Van der Hilst, R.D.Using ScP precursors to search for mantle structures beneath 1800 km depth.Geophysical Research Letters, Vol. 30, 8, 4, 10.1029/2002 GLO16023MantleGeophysics - seismics Discontinuity
DS200412-0295
2003
Van der Hilst, R.D.Castle, J.C., Van der Hilst, R.D.Searching for seismic scattering off mantle interfaces between 800 km and 2000 km depth.Journal of Geophysical Research, Vol. 108, 2, ESE 13MantleGeophysics - seismics Lower mantle
DS200412-1095
2003
Van der Hilst, R.D.Lebedev, S., Chevrot, S.,Van der Hilst, R.D.Correlation between shear speed structure and thickness of the mantle transition zone.Physics of the Earth and Planetary Interiors, Vol. 136, 1-2, pp. 25-40.MantleGeophysics - seismics
DS200412-1654
2004
Van der Hilst, R.D.Replumaz, A., Karason, H., Van der Hilst, R.D., Besse, J., Tapponnier, P.4 D evolution of SE Asia's mantle from geological reconstructions and seismic tomography.Earth and Planetary Science Letters, Vol. 221, 1-4, pp. 103-115.India, Asia, ChinaGeophysics - seismics, tectonics
DS200412-1681
2003
Van der Hilst, R.D.Rohrman, M., Van der Beek, P.A., Van der Hilst, R.D., Reemst, P.Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantle upwelling.Geological Society of London, Special Publication, No. 196, pp. 27-44.MantlePlume
DS200412-1723
2004
Van der Hilst, R.D.Saltzer, R.L., Stutzmann, E., Van der Hilst, R.D.Poisson's ratio in the lower mantle beneath Alaska: evidence for compositional heterogeneity.Journal of Geophysical Research, Vol. 109, B6, B06301, June 9, 10.1029/2003 JB002712United States, AlaskaGeochemistry
DS200412-1835
2003
Van der Hilst, R.D.Simons, F.J., Van der Hilst, R.D.Seismic and mechanical anisotropy and the past and present deformation of the Australian lithosphere.Earth and Planetary Science Letters, Vol. 211, 3-4, pp. 271-86.AustraliaGeophysics - seismics, tectonics
DS200512-1117
2004
Van der Hilst, R.D.Van der Hilst, R.D.Changing views on Earth's deep mantle.Science, No. 5697, Oct. 29, p. 817.MantleGeophysics
DS200512-1126
2004
Van der Hilst, R.D.Vangeren, L., Deschamps, F., Van der Hilst, R.D.Geophysical evidence for chemical variations in the Australian continental mantle.Geophysical Research Letters, Vol. 31, 17, Sept. 16, L17607AustraliaGeophysics - geochemistry
DS200612-0811
2006
Van der Hilst, R.D.Li, C., Van der Hilst, R.D., Toksoz, M.N.Constraining P wave velocity variations in the upper mantle beneath southeast Asia.Physics of the Earth and Planetary Interiors, Vol. 154, 2, Feb. 16, pp. 180-195.Asia, ChinaGeophysics - seismics
DS200612-1435
2005
Van der Hilst, R.D.Trampert, J., Van der Hilst, R.D.Towards a qunatitative interpretation of global seismic tomography.American Geophysical Union, Geophysical Monograph, ed. Van der Hilst, Earth's Deep mantle, structure ...., No. 160, pp. 47-62.MantleTomography
DS200612-1462
2005
Van der Hilst, R.D.Van der Hilst, R.D., Bass, J.D., Matas, J., Trampert, J.Earth's deep mantle structure, composition, and evolution - an introduction.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 1-8.MantleTectonics
DS200612-1463
2005
Van der Hilst, R.D.Van der Hilst, R.D., De Hoop, M.V.Banana doughnut kernels and mantle tomography.Geophysical Journal International, Vol. 163, 3, Dec. pp. 956-961.MantleGeophysics - tomography
DS200712-0660
2007
Van der Hilst, R.D.Ma, P., Wang, P., Tenorio, L., de Hoop, M.V., Van der Hilst, R.D.Imaging of structure at and near the core mantle boundary using a generalized radon transform2. inference of singularities.Journal of Geophysical Research, Vol. 112, B8, B08403.MantleGeophysics - seismics
DS200712-0890
2007
Van der Hilst, R.D.Ren, Y., Stutmann, E., Van der Hilst, R.D., besse, J.Understanding seismic heterogeneities in the lower mantle: beneath the Americas from seismic tomography and plate tectonic history.Journal of Geophysical Research, Vol. 112, B1, Jan. 17, B01302.MantleTectonics, geophysics
DS200812-0977
2008
Van der Hilst, R.D.Royden, L.H., Burchfiel, B.C., Van der Hilst, R.D.The geological evolution of Tibetan Plateau.Science, Vol. 321, no. 5892, August 22, pp. 1054-1058.Asia, TibetTectonics
DS200812-1236
2008
Van der Hilst, R.D.Wang, P., De Hoop, M.V., Van der Hilst, R.D.Imaging the lowermost mantle 'D' and the core mantle boundary with SKKS coda waves.Geophysical Journal International, Vol. 175, 1, pp. 103-115.MantleBoundary
DS200912-0790
2009
Van der Hilst, R.D.Van Summeren, J.R., Vandenberg, A.P., Van der Hilst, R.D.Upwellings from a deep mantle reservoir filtered at the 660 km phase transition in thermochemical convection models and implications for intra-plate volcanism.Physics of the Earth and Planetary Interiors, Vol. 172, 3-4, pp. 210-224.MantleGeothermometry
DS200712-1108
2007
Van der Hislt, R.Van der Hislt, R.Boldly going deeper into Earth: as we look closer and in ever greater detail at the crust and mantle, we are discovering that the interior layers of Earth ....Geotimes, Vol. 52, 7, pp. 34-37.MantleInteresting and enigmatic - models
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1998
Van der Kerkof, A.M.Xiao, Y.L., Hoefs, J., Van der Kerkof, A.M., Zheng, Y.Fluid inclusions in ultra high pressure eclogites from the Dabie Shan, eastern China.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1667-8.ChinaEclogites, metamorphic, Deposit - Dabie Shan
DS200512-0534
2004
Van der Klauw, S.N.G.C.King, R.L., Bebout, G.E., Kobayashi, E., Van der Klauw, S.N.G.C.Ultrahigh pressure metabasaltic garnets as probes into deep subduction zone chemical weathering.Geochemistry, Geophysics, Geosystems: G3, Vol. 5, pp. Q12J14 10.1029/2004 GC000746MantleSubduction, eclogite
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2005
Van der Klauw, S.N.G.C.King, R.L., Bebout, G.E., Kobayashi, K., Nakamura, E., Van der Klauw, S.N.G.C.Ultrahigh pressure metabasaltic garnets as probes into deep subduction zone chemical cycling.Geochemistry, Geophysics, Geosystems: G3, Vol. 5, Q12J14, doi:10.1029/2004 GC000746TechnologyUHP
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2003
Van der Kruk, J.Van der Kruk, J., Wapenaar, C.P.A., Fokkema, J.T., Van den Berg, P.M.Three dimensional imaging of multicomponent ground penetrating radar dataGeophysics, Vol. 68, 4, pp. 1241-54.GlobalGeophysics - radar not specific to diamonds
DS200412-2036
2003
Van der Kruk, J.Van der Kruk, J., Wapenaar, C.P.A., Fokkema, J.T., Van den Berg, P.M.Three dimensional imaging of multicomponent ground penetrating radar data.Geophysics, Vol. 68, 4, pp. 1241-54.TechnologyGeophysics - radar not specific to diamonds
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1965
Van der laan, H.L.Van der laan, H.L.The Sierra Leone Diamonds: an Economic Study Covering the Years 1952-1961.London: Oxford University Press, 234P.Sierra Leone, West AfricaEconomics, Production, History, Kimberley
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1995
Van der Laan, S.R.Foley, S.F., Van der Laan, S.R., Horn, I.Experimental melting reactions amphibole and phlogopite bearing mantle vein assemblages -trace elementsProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 161-63.GlobalPetrology -experimenta, Mantle -alkaline magmas
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1995
Van der Laan, S.R.Klemme, S., Van der Laan, S.R., et al.Experimentally determined trace and minor elements partitioning between clinopyroxene and carbonatite meltEarth and Planetary Science Letters, Vol. 133, No. 3-4, July 15, pp. 439-448.GlobalCarbonatite
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1998
Van der Laan, S.R.Foley, S.F., Musselwhite, D.S., Van der Laan, S.R.Melting processes in veined lithospheric mantle in cratonic and non-cratonic settings.7th International Kimberlite Conference Abstract, pp. 220-223.MantleMelt temperatures, Experimental petrology
DS2001-0325
2001
Van der LeeFouch, M.J., James, Silver, VanDecar, Van der LeeImaging broad ranges in structural variations beneath the Kaapvaal and Zimbabwe Cratons, southern Africa.Slave-Kaapvaal Workshop, Sept. Ottawa, 5p. abstractSouth Africa, ZimbabweGeophysics - seismics, Tomography - Kimberley array
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1995
Van der Lee, S.Van der Lee, S.North American Upper Mantle 3D S- velocity structureEos, Abstracts, Vol. 76, No. 17, Apr 25, p. S 200.Mantle, North AmericaGeophysics -seismics, Structure
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1995
Van der Lee, S.Van der Lee, S.The Farallon plate in the North American upper mantleEos, Vol. 76, No. 46, Nov. 7. p.F422. Abstract.Mantle, North AmericaUpper mantle
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1997
Van der Lee, S.Van der Lee, S., Nolet, G.Upper mantle S velocity structure of North AmericaJournal of Geophysical Research, Vol. 102, No. 10, Oct. 10, pp. 22, 815-838.North America, United States, CanadaMantle, Tectonics - geophysics - seismics
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2001
Van der Lee, S.Van der Lee, S., Van De Car, Fouch, JamesCombined sensitivity to the Kaapvaal tectosphere of regional and teleseismic surface and S Waves.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractSouth AfricaGeophysics - seismics, Lithosphere
DS2002-0584
2002
Van der Lee, S.Goes, S., Van der Lee, S.Thermal structure of the North American uppermost mantle inferred from seismic tomography.Journal of Geophysical Research, Vol. 107, No. 3, pp. ETG 2.MantleGeothermometry, Geophysics - seismics
DS2002-0585
2002
Van der Lee, S.Goes, S., Van der Lee, S.Thermal structure of the North American uppermost mantle inferred from seismic tomography.Journal of Geophysical Research, Vol.107,B3, pp.ETG 2-1-20North America, United States, Midcontinent, WyomingSubduction, Tomography, tectonics, seismics
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2002
Van der lee, S.Goes, S., Van der lee, S.Thermal structure of the North American uppermost mantle inferred from seismic tomography.Journal of Geophysical Research, Vol. 107, No.3, pp.United States, Canada, North AmericaGeothermometry
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2002
Van Der Lee, S.Li, A., Fischer, K.M., Van Der Lee, S., Wysession, M.E.Crust and upper mantle discontinuity structure beneath eastern North AmericaJournal of Geophysical Research, Vol. 107, No. 5, ESE7AppalachiaGeophysics - seismics, Core-mantle boundary
DS2002-0939
2002
Van der Lee, S.Li, Aibing, Fischer, K.M., Van der Lee, S., Wysession, M.Crust and upper mantle discontinuity structure beneath eastern North AmericaJournal of Geophysical Research, Vol.107,5, May 28, 10.1029/2002JB001891AppalachiaCore - mantle boundary, Geophysics - seismics
DS2002-1640
2002
Van der Lee, S.Van der Lee, S.High resolution estimates of lithospheric thickness from Missouri to Massachusetts, USA.Earth and Planetary Science Letters, Vol. 203, 1, pp. 15-23.Appalachia, MissouriGeophysics - seismics
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2003
Van Der Lee, S.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantleScience, No. 5625, June 6, p. 1556-57.MantleWater
DS200412-0567
2004
Van Der Lee, S.Fouch, M.J., James, D.E., Van De Car, J.C., Van Der Lee, S.Mantle seismic structure beneath the Kaapvaal and Zimbabwe Cratons.South African Journal of Geology, Vol. 107, 1/2, pp. 33-44.Africa, South Africa, ZimbabweGeophysics - seismics, tectonics, magmatism
DS200412-1227
2004
Van der Lee, S.Marone, F., Van der Lee, S., Giardini, D.Three dimensional upper mantle S velocity model for the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 158, 1, pp.109-130.Africa, EuropeTectonics, geophysics - seismics
DS200412-1228
2004
Van der Lee, S.Marone, F., Van der Meijde, M., Van der Lee, S., Giadini, D.Joint inversion of local, regional and teleseismic dat a for crustal thickness in the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 154, 2, pp. 499-514.Europe, AsiaGeophysics - seismics, boundary
DS200412-2037
2003
Van der Lee, S.Van der Lee, S.Notes: 3 D structure of continental upper mantle, derived from seismograms.Journal Geological Society of India, Vol. 62, 1, pp. 121-122.IndiaGeophysics - seismics
DS200412-2039
2003
Van Der Lee, S.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantle.Science, No. 5625, June 6, p. 1556-57.MantleWater
DS200612-1464
2005
Van der Lee, S.Van der Lee, S., Frederiksen, A.Surface wave tomography applied to the North American Upper Mantle.American Geophysical Union, Geophysical Monograph, No. 157, pp. 67-80.United States, CanadaGeophysics - seismics
DS200612-1564
2006
Van der lee, S.Yang, T., Shen, Y., Van der lee, S., Solomon, S.C., Hung, S.H.Upper mantle structure beneath the Azores hotspot from finite frequency seismic tomography.Earth and Planetary Science Letters, Vol. 250, 1-2, pp. 11-26.AzoresGeophysics - seismics
DS200712-0104
2006
Van der Lee, S.Braunmiller, J., Van der Lee, S., Doermann, L.Mantle transition zone thickness in the central South American subduction zone.American Geophysical Union, Geophysical Monograph, No. 168, pp. 215-224.South AmericaSubduction
DS200712-0312
2007
Van der Lee, S.Feng, M., Van der Lee, S., Assumpca, M.Upper mantle structure of South America from joint inversion of waveforms and fundamental mode group velocities of Rayleigh waves.Journal of Geophysical Research, Vol. 112, B4, B04312.South AmericaGeophysics - seismics
DS200712-0476
2007
Van der Lee, S.Jacobsen, S.D., Van der Lee, S., Smyth, J.R., Holl, C.M.Detecting hydration in the Earth's mantle.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.187-188.MantleWater
DS200712-0477
2007
Van der Lee, S.Jacobsen, S.D., Van der Lee, S., Smyth, J.R., Holl, C.M.Detecting hydration in the Earth's mantle.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.187-188.MantleWater
DS200812-1199
2008
Van der Lee, S.Van der Lee, S., Regenauer Lieb, K., Yuen, D.A.The role of water in connecting past and future episodes of subduction.Earth and Planetary Science Letters, Vol. 273, 1-2, Aug. 30, pp. 15-27.MantleSubduction
DS200812-1200
2008
Van der Lee, S.Van der Lee, S., Regenauer-Lieb, K., Yuen, D.A.The role of water in connecting past and future episodes of subduction.Earth and Planetary Science Letters, Vol. 273, pp. 15-27.MantleSubduction - water
DS201012-0457
2010
Van der Lee, S.Lloyd, S., Van der Lee, S., Franka, G.S., Assumpcio, M., Feng, W.Moho map of South America from receiver functions and surface waves.Journal of Geophysical Research, Vol. 115, B 11, B11315.South AmericaGeophysics - seismics
DS201112-0171
2011
Van der Lee, S.Chang, S-J., Van der Lee, S.Mantle plumes and associated flow beneath Arabia and East Africa.Earth and Planetary Science Letters, Vol. 302, pp. 448-454.AfricaHotspots, tectonics
DS201312-0278
2013
Van der Lee, S.Frederiksen, A.W., Bollmann, T., Darbyshire, F., Van der Lee, S.Modification of continental lithosphere by tectonic processes: a tomographic image of central North America.Journal of Geophysical Research, 50060Canada, United StatesTomography - Laurentia, Superior
DS1991-1777
1991
Van der Leeden, F.Van der Leeden, F.Groundwater bibliographyGeraghty and Miller Publ, 507p. approx. $ 70.00GlobalGroundwater bibliography, Book-ad
DS1993-1642
1993
Van der Linde, A.Van der Linde, A.On least squares estimation of generalized covariance functionsMathematical Geology, Vol. 25, No. 1, January pp. 1-8GlobalGeostatistics, Computer Program
DS201212-0339
2012
Van der Linde, G.Jelsma, H.,Krishnan, S.U., Perritt, S.,Kumar, M., Preston, R., Winter, F., Lemotlo, L., Costa, J., Van der Linde, G., Facatino, M., Posser, A., Wallace, C., Henning, A., Joy, S., Chinn, I., Armstrong, R., Phillips, D.Kimberlites from central Angola: a case stidy of exploration findings.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, AngolaOverview of kimberlites
DS201412-0427
2013
van der Linde, G.Jelsma, H., Krishnan, U., Perritt, S., Preston, R., Winter, F., Lemotlo, L., van der Linde, G., Armstrong, R., Phillips, D., Joy, S., Costa, J., Facatino, M., Posser, A., Kumar, M., Wallace, C., Chinn, I., Henning, A.Kimberlites from central Angola: a case study of exploration findings.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 173-190.Africa, AngolaExploration - kimberlites
DS201601-0038
2015
Van Der Linde, G.Perritt, S., Preston, R., Viljoen, F., Van Der Linde, G.Morphology, micro-structure and chemistry of a deformed garnet megacryst suite from Montelo kimberlite, Free State Province, South Africa.South African Journal of Geology, Vol. 118, 4, pp. 439-454.Africa, South AfricaDeposit - Montelo
DS201809-2047
2018
Van der Linde, G.Joy, S., Van der Linde, G., Choudbury, A.K., Deb, G.K., Tappe, S.Reassembly of the Dharwar and Bastar cratons at ca. 1 Ga: evidence from multiple tectonothermal events along the Karimnagar granulite belt and Khammam schist belt, southern India.Journal of Earth System Science, Vol. 127, 6, pp. 76- doi:10.1007/s12040-018-0988-2Indiacratons

Abstract: The northern part of the Nellore-Khammam schist belt and the Karimnagar granulite belt, which are juxtaposed at high angle to each other have unique U-Pb zircon age records suggesting distinctive tectonothermal histories. Plate accretion and rifting in the eastern part of the Dharwar craton and between the Dharwar and Bastar craton indicate multiple and complex events from 2600 to 500 Ma. The Khammam schist belt, the Dharwar and the Bastar craton were joined together by the end of the Archaean. The Khammam schist belt had experienced additional tectonic events at ?1900 and ?1600 Ma. The Dharwar and Bastar cratons separated during development of the Pranhita-Godavari (P-G) valley basin at ?1600 Ma, potentially linked to the breakup of the Columbia supercontinent and were reassembled during the Mesoproterozoic at about 1000 Ma. This amalgamation process in southern India could be associated with the formation of the Rodinia supercontinent. The Khammam schist belt and the Eastern Ghats mobile belt also show evidence for accretionary processes at around 500 Ma, which is interpreted as a record of Pan-African collisions during the Gondwana assembly. From then on, southern India, as is known today, formed an integral part of the Indian continent.
DS201012-0810
2010
Van der Meer, D.G.Van der Meer, D.G., Spakman, W., Van Hinsbergen, D.J.J., Amaru, M.L., Torsvik, T.H.Towards absolute plate motions constrained by lower mantle slab remnants.Nature Geoscience, Vol. 3, Jan. pp. 36-40.MantleTectonics, Pangea
DS201212-0071
2012
Van der Meer, D.G.Biggin, A.J., Steinberger, B., Aubert, J., Suttle, N., Holme, R., Torsvik, H., Van der Meer, D.G., Van Hinsbergen, J.J.Possible links between long term geomagnetic variations and whole mantle convection processes.Nature Geoscience, Vol. 5, pp. 526-533.MantleConvection
DS201811-2616
2018
van der Meer, D.G.van der Meer, D.G., van Hinsbergen, D.J.J., Spakman, W.Atlas of the underworld: slab remnants in the mantle, their sinking history, and a new outlook on lower mantle viscosity.Tectonophysics, Vol. 773, 1, pp. 309-448.Mantlegeophysics - seismic

Abstract: Across the entire mantle we interpret 94 positive seismic wave-speed anomalies as subducted lithosphere and associate these slabs with their geological record. We document this as the Atlas of the Underworld, also accessible online at www.atlas-of-the-underworld.org, a compilation comprising subduction systems active in the past ~ 300 Myr. Deeper slabs are correlated to older geological records, assuming no relative horizontal motions between adjacent slabs following break-off, using knowledge of global plate circuits, but without assuming a mantle reference frame. The longest actively subducting slabs identified reach the depth of ~ 2500 km and some slabs have impinged on Large Low Shear Velocity Provinces in the deepest mantle. Anomously fast sinking of some slabs occurs in regions affected by long-term plume rising. We conclude that slab remnants eventually sink from the upper mantle to the core-mantle boundary. The range in subduction-age versus - depth in the lower mantle is largely inherited from the upper mantle history of subduction. We find a significant depth variation in average sinking speed of slabs. At the top of the lower mantle average slab sinking speeds are between 10 and 40 mm/yr, followed by a deceleration to 10-15 mm/yr down to depths around 1600-1700 km. In this interval, in situ time-stationary sinking rates suggest deceleration from 20 to 30 mm/yr to 4-8 mm/yr, increasing to 12-15 mm/yr below 2000 km. This corroborates the existence of a slab deceleration zone but we do not observe long-term (> 60 My) slab stagnation, excluding long-term stagnation due to compositional effects. Conversion of slab sinking profiles to viscosity profiles shows the general trend that mantle viscosity increases in the slab deceleration zone below which viscosity slowly decreases in the deep mantle. This is at variance with most published viscosity profiles that are derived from different observations, but agrees qualitatively with recent viscosity profiles suggested from material experiments.
DS201902-0328
2018
Van der Meer, D.G.Van der Meer, D.G., van Hinsbergen, D.J.J., Spakman, W.Atlas of the underworld: slab remnants in the mantle, their sinking history, and a new outlook on lower mantle viscosity.Tectonophysics, Vol. 723, 1, pp. 309-448.Mantlesubduction

Abstract: Across the entire mantle we interpret 94 positive seismic wave-speed anomalies as subducted lithosphere and associate these slabs with their geological record. We document this as the Atlas of the Underworld, also accessible online at www.atlas-of-the-underworld.org, a compilation comprising subduction systems active in the past ~ 300 Myr. Deeper slabs are correlated to older geological records, assuming no relative horizontal motions between adjacent slabs following break-off, using knowledge of global plate circuits, but without assuming a mantle reference frame. The longest actively subducting slabs identified reach the depth of ~ 2500 km and some slabs have impinged on Large Low Shear Velocity Provinces in the deepest mantle. Anomously fast sinking of some slabs occurs in regions affected by long-term plume rising. We conclude that slab remnants eventually sink from the upper mantle to the core-mantle boundary. The range in subduction-age versus - depth in the lower mantle is largely inherited from the upper mantle history of subduction. We find a significant depth variation in average sinking speed of slabs. At the top of the lower mantle average slab sinking speeds are between 10 and 40 mm/yr, followed by a deceleration to 10-15 mm/yr down to depths around 1600-1700 km. In this interval, in situ time-stationary sinking rates suggest deceleration from 20 to 30 mm/yr to 4-8 mm/yr, increasing to 12-15 mm/yr below 2000 km. This corroborates the existence of a slab deceleration zone but we do not observe long-term (> 60 My) slab stagnation, excluding long-term stagnation due to compositional effects. Conversion of slab sinking profiles to viscosity profiles shows the general trend that mantle viscosity increases in the slab deceleration zone below which viscosity slowly decreases in the deep mantle. This is at variance with most published viscosity profiles that are derived from different observations, but agrees qualitatively with recent viscosity profiles suggested from material experiments.
DS1995-1957
1995
Van der Meer, F.Van der Meer, F.Estimating and simulating degree of serpentinization of peridotites usinghyper spectral remote sensed imageryNonrenewable Resources, Vol. 4, No. 1, Spring pp. 84-98GlobalRemote sensing, geostatistics, Ronda, ultramafics
DS201412-0958
2014
Van der Meer, H.A.Waight, T.E., Van der Meer, H.A., Palin, J.M., Cooper, A.F.,Munker, C.Metasomatized ancient lithospheric mantle beneath the young Zealandia microcontinent and its role in HIMU-like intraplate magmatism. Geophysics, Geochemistry, Geosystems, Vol. 15, pp. 3477-3501.New ZealandMagmatism
DS201710-2273
2017
Van der Meer, Q.Van der Meer, Q., Klaver, M., Reisberg, L., Riches, A. J.V., Davies, G.R.Preservation of an Archean whole rock Re-Os isochron for the Venetia lithospheric mantle: evidence for rapid crustal recycling and lithosphere stabilization at 3.3 Ga.Geochimica et Cosmochimica Acta, Vol. 216, pp. 242-263.Africa, South Africadeposit - Venetia
DS201112-1073
2011
Van der Meer, Q.H.A.Van der Meer, Q.H.A., Klaver, M., Reisberg, L., Davidheiser, B., Davies, G.R.The age and origin of the Limpopo sub-continental lithospheric mantle.Goldschmidt Conference 2011, abstract p.2064.Africa, South AfricaVenetia
DS201212-0744
2012
Van der Meer, Q.H.A.Van der Meer, Q.H.A., Klaver, M., Reisberg, L., Davies, G.R.The age and origin of the Limpopo ( South Africa) subcontinental lithospheric mantle.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, South AfricaGeochronology
DS201312-0933
2013
Van der Meer, Q.H.A.Van der Meer, Q.H.A., Klaver, M., Waight, T.E., Davies, G.R.The provenance of sub-cratonic mantle beneath the Limpopo mobile belt, (South Africa).Lithos, Vol. 170-171, pp. 90-104.Africa, South Africa, ZimbabweCraton, geothermobarometry, diamond potential
DS201709-2068
2017
van der Meer, Q.H.A.van der Meer, Q.H.A., Klaver, M., Reisberg, L., Riches, A.J.V., Davies, G.R.Preservation of an Archaean whole rock Re-Os isochron for the Venetia lithospheric mantle: evidence for rapid crustal recycling and lithospheric stabilization at 3.3 Ga.Geochimica et Cosmochimica Acta, in press available, 22p.Africa, South Africadeposit - Venetia

Abstract: Re-Os and platinum group element analyses are reported for peridotite xenoliths from the 533 Ma Venetia kimberlite cluster situated in the Limpopo Mobile Belt, the Neoarchaean collision zone between the Kaapvaal and Zimbabwe Cratons. The Venetian xenoliths provide a rare opportunity to examine the state of the cratonic lithosphere prior to major regional metasomatic disturbance of Re-Os systematics throughout the Phanerozoic. The 32 studied xenoliths record Si-enrichment that is characteristic of the Kaapvaal lithospheric mantle and can be subdivided into five groups based on Re-Os analyses. The most pristine group I samples (n = 13) display an approximately isochronous relationship and fall on a 3.28 ± 0.17 Ga (95 % conf. int.) reference line that is based on their mean TMA age. This age overlaps with the formation age of the Limpopo crust at 3.35–3.28 Ga. The group I samples derive from ?50 to ?170 km depth, suggesting coeval melt depletion of the majority of the Venetia lithospheric mantle column. Group II and III samples have elevated Re/Os due to Re addition during kimberlite magmatism. Group II has otherwise undergone a similar evolution as the group I samples with overlapping 187Os/188Os at eruption age: 187Os/188OsEA, while group III samples have low Os concentrations, unradiogenic 187Os/188OsEA and were effectively Re-free prior to kimberlite magmatism. The other sample groups (IV and V) have disturbed Re-Os systematics and provide no reliable age information. A strong positive correlation is recorded between Os and Re concentrations for group I samples, which is extended to groups II and III after correction for kimberlite addition. This positive correlation precludes a single stage melt depletion history and indicates coupled remobilisation of Re and Os. The combination of Re-Os mobility, preservation of the isochronous relationship, correlation of 187Os/188Os with degree of melt depletion and lack of radiogenic Os addition puts tight constraints on the formation and subsequent evolution of Venetia lithosphere. First, melt depletion and remobilisation of Re and Os must have occurred within error of the 3.28 Ga mean TMA age. Second, the refractory peridotites contain significant Re despite recording >40 % melt extraction. Third, assuming that Si-enrichment and Re-Os mobility in the Venetia lithospheric mantle were linked, this process must have occurred within ?100 Myr of initial melt depletion in order to preserve the isochronous relationship. Based on the regional geological evolution, we propose a rapid recycling model with initial melt depletion at ?3.35 Ga to form a tholeiitic mafic crust that is recycled at ?3.28 Ga, resulting in the intrusion of a TTG suite and Si-enrichment of the lithospheric mantle. The non-zero primary Re contents of the Venetia xenoliths imply that TRD model ages significantly underestimate the true depletion age even for highly depleted peridotites. The overlap of the ?2.6 Ga TRD ages with the time of the Kaapvaal-Limpopo collision is purely fortuitous and has no geological significance. Hence, this study underlines the importance of scrutiny if age information is to be derived from whole rock Re-Os analyses.
DS201904-0747
2019
van der Meer, Q.H.A.Howarth, G.H., Moore, A.E., Harris, C., van der Meer, Q.H.A., Le Roux , P.Crustal versus mantle origin of carbonate xenoliths from Kimberley region kimberlites using C-O-Sr-Nd-Pb isotopes and trace element abundances.Geochimica et Cosmochimica Acta, in press available 42p.Africa, South Africageochronology
DS201905-1043
2019
van der Meer, Q.H.A.Howarth, G.H., Moore, A.E., Harris, C., van der Meer, Q.H.A., Le Roux, P.Crustal versus mantle origin of carbonate xenoliths from Kimberly region kimberlites using C-O-Sr-Nd-Pb isotopes and trace element abundances.Geochimica et Cosmochimica Acta, in press available, 16p.Africa, South Africadeposit - Kimberly region

Abstract: Carbonate-bearing assemblages in the mantle have been interpreted to be the source for Si-undersaturated, CO2-rich magmas, including kimberlites. However, direct evidence for carbonate in the mantle is rare in the contemporary literature. Here we present petrography, trace element, and C-O-Sr-Nd-Pb isotope composition for a suite of carbonate xenoliths from the Kimberley region kimberlites to ascertain their mantle or crustal origin and gain insight to the potential for the occurrence of carbonate in the mantle. Carbonate xenoliths were found in large kimberlite blocks from the Bultfontein kimberlite and Big Hole region. The xenoliths are characterised by pale green alteration margins made of fine-grained microlites of an unknown mineral as well as spherules surrounded by glassy material. They are generally 1–4?cm in size, coarse-grained (1–2?mm), and comprised entirely of calcite. Carbonate xenoliths from the Bultfontein kimberlite have low total REE concentrations (0.2–4.9?ppm), constant 87Sr/86Sri (0.7047–0.7049) combined with variable ?Ndi (?0.1 to ?26.2) and 206Pb/204Pbi, 207Pb/204Pbi, and 208Pb/204Pbi of 16.7–18.8, 15.3–15.6, 36.5–38.4, respectively. Xenoliths from the Big Hole sample have higher 87Sr/86Sri (0.7088–0.7095), lower ?Ndi (?24.5 to ?3.8), and 206Pb/204Pbi, 207Pb/204Pbi, and 208Pb/204Pbi of 18.9–19.9, 15.7–15.8, 38.4–38.8, respectively. The ?13C values for both Bultfontein (?5.7 to ?6.6‰) and Big Hole (?4.7 to ?5.4‰) carbonates are within the typical range expected for mantle-derived carbonate. The ?18O values (15.5–17.5‰) are higher than those of mantle silicate rocks, indicative of late-stage low-temperature interaction with fluids; a common feature of groundmass calcite in the Kimberley kimberlites. The Sr- and C- isotope composition of the Bultfontein xenoliths indicates a mantle origin whereas the Big Hole xenolith Sr- and C-isotopes are more ambiguous. Isotope mixing models are inconsistent with interaction between the host kimberlite and carbonate xenoliths. Correlation between ?Ndi and ?18O values for the Bultfontein xenoliths indicates late-stage interaction with low-temperature fluids, which may also be responsible for the large range in ?Ndi. This in turn indicates that the highest ?Ndi of ?0.1 represents the primary carbonate xenolith signature, and this value overlaps typical Group I kimberlites. We discuss two possible origins for the carbonate xenoliths. (1) Carbonate xenoliths from the sub-continental lithospheric mantle (SCLM), where quenched margins and the large range of ?Ndi are related to formation in the mantle. (2) Carbonate xenoliths from an earlier phase of carbonatite magmatism. The similarity of isotope signatures of the Bultfontein carbonates to Group I kimberlite may further suggest a link between kimberlite and carbonatite volcanism such as observed elsewhere in the world.
DS201905-1082
2019
van der Meer, Q.H.A.van der Meer, Q.H.A., Scott, J.M., Serre, S.H., Whitehouse, M.J., Kristoffersen, M., Le Roux, P.J., Pope, E.C.Low delta 18 O zircon xenocrysts in alkaline basalts; a window into the complex carbonatite-metasomatic history of the Zealandia lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 254, pp. 21-39.New Zealandmetasomatism

Abstract: Megacrystic zircon grains from alkaline basaltic fields are rare but can provide fundamental insights into mantle metasomatic processes. Here, we report in-situ U-Pb ages, trace element concentrations and hafnium and oxygen isotopes for fourteen zircon megacrysts from two intraplate alkaline basalt locations in New Zealand. U-Pb ages indicate the zircons crystallised between 12.1 and 19.8 Ma. Zircon oxygen isotopic compositions range from low to mantle-like compositions (grain average ? ¹? O = 3.8-5.1‰). Hafnium isotopes (?Hf (t) = +3.3 to +10.4) mostly overlap with intraplate mafic rocks and clinopyroxene in metasomatized peridotitic mantle xenoliths but show no correlation with most trace element parameters or oxygen isotopes. The zircons are interpreted to have formed by the reaction between low-degree melts derived from pre-existing mantle metasomes and the depleted mantle lithosphere prior to eruption and transport to the surface. The low Hf concentration, an absence of Eu anomalies, and elevated U/Yb compared to Nb/Yb in the megacrystic zircons are interpreted to show that the source metasomes comprised subduction- and carbonatite-metasomatised lithospheric mantle. As these trace element characteristics are common for megacrystic zircon in intra-plate basaltic fields globally, they suggest the prevalence of subduction- and carbonatite-metsasomatised mantle under these intraplate volcanic regions. The unusually low ? ¹? O was likely present prior to metasomatic enrichment and may have resulted from high-temperature hydrothermal alteration during initial mantle lithosphere formation at a mid ocean ridge or, possibly, during subduction-related processes associated with continent formation. The combination of proportionally varied contributions from carbonatite- and subduction-metasomatised lithospheric melts with asthenospheric melts may explain the variety of primitive intraplate basalt compositions, including low ? ¹? O reported for some local intraplate lavas.
DS2003-1411
2003
Van der MeijdeVan der MeijdeWet mantle below the MediterraneanScience, No. 5625, June 6, p. 1556.MantleSubduction - water
DS200412-2038
2003
Van der MeijdeVan der MeijdeWet mantle below the Mediterranean.Science, No. 5625, June 6, p. 1556.MantleSubduction - water
DS2003-1412
2003
Van der Meijde, M.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantleScience, No. 5625, June 6, p. 1556-57.MantleWater
DS200412-1228
2004
Van der Meijde, M.Marone, F., Van der Meijde, M., Van der Lee, S., Giadini, D.Joint inversion of local, regional and teleseismic dat a for crustal thickness in the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 154, 2, pp. 499-514.Europe, AsiaGeophysics - seismics, boundary
DS200412-2039
2003
Van der Meijde, M.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantle.Science, No. 5625, June 6, p. 1556-57.MantleWater
DS201112-1036
2011
Van der Meijde, M.Tedia, G.E., Van der Meijde, M., Nyblade, A.A., Ven der Meer, F.D.A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution.Geophysical Journal International, Vol. 187, 1, pp. 1-9.AfricaGeophysics - gravity
DS201502-0118
2015
van der Meijde, M.van der Meijde, M., Fadel, I., Ditmar, P., Hamayun, M.Uncertainties in crustal thickness models for dat a sparse environments: a review for South America and Africa.Journal of Geodynamics, Vol. 84, 1, pp. 1-18.South America, AfricaGeophysics - seismics
DS202007-1131
2020
Van der Meijde, M.Chisenga, C., Van der Meijde, M., Yan, J., Fadel. I., Atekwana, E.A., Steffen, R., Ramotoroko, C.Gravity derived crustal thickness model of Botswana: its implication for the Mw 6.5 April 3, 2017, Botswana earthquake. Tectonophysics, Vol. 787, 228479 12p. PdfAfrica, Botswanageophysics - gravity

Abstract: Botswana experienced a Mw 6.5 earthquake on 3rd April 2017, the second largest earthquake event in Botswana's recorded history. This earthquake occurred within the Limpopo-Shashe Belt, ~350 km southeast of the seismically active Okavango Rift Zone. The region has no historical record of large magnitude earthquakes or active faults. The occurrence of this earthquake was unexpected and underscores our limited understanding of the crustal configuration of Botswana and highlight that neotectonic activity is not only confined to the Okavango Rift Zone. To address this knowledge gap, we applied a regularized inversion algorithm to the Bouguer gravity data to construct a high-resolution crustal thickness map of Botswana. The produced crustal thickness map shows a thinner crust (35-40 km) underlying the Okavango Rift Zone and sedimentary basins, whereas thicker crust (41-46 km) underlies the cratonic regions and orogenic belts. Our results also show localized zone of relatively thinner crust (~40 km), one of which is located along the edge of the Kaapvaal Craton within the MW 6.5 Botswana earthquake region. Based on our result, we propose a mechanism of the Botswana Earthquake that integrates crustal thickness information with elevated heat flow as the result of the thermal fluid from East African Rift System, and extensional forces predicted by the local stress regime. The epicentral region is therefore suggested to be a possible area of tectonic reactivation, which is caused by multiple factors that could lead to future intraplate earthquakes in this region.
DS202011-2067
2020
van der Meijde, M.White-Gaynor, A.L., Nyblade, A.A., Durrheim, R., Raveloson, R., van der Meijde, M., Fadel, I., Paulssen, H., Kwadiba, M., Ntibinyane, O., Titus, N., Sitali, M.Lithospheric boundaries and upper mantle structure beneath southern Africa imaged by P and S wave velocity models.Geochemistry, Geophysics, Geosystems, 10.1029/GC008925 20p. PdfAfrica, South AfricaGeophysics, seismic

Abstract: We report new P and S wave velocity models of the upper mantle beneath southern Africa using data recorded on seismic stations spanning the entire subcontinent. Beneath most of the Damara Belt, including the Okavango Rift, our models show lower than average velocities (?0.8% Vp; ?1.2% Vs) with an abrupt increase in velocities along the terrane's southern margin. We attribute the lower than average velocities to thinner lithosphere (~130 km thick) compared to thicker lithosphere (~200 km thick) immediately to the south under the Kalahari Craton. Beneath the Etendeka Flood Basalt Province, higher than average velocities (0.25% Vp; 0.75% Vs) indicate thicker and/or compositionally distinct lithosphere compared to other parts of the Damara Belt. In the Rehoboth Province, higher than average velocities (0.3% Vp; 0.5% Vs) suggest the presence of a microcraton, as do higher than average velocities (1.0% Vp; 1.5% Vs) under the Southern Irumide Belt. Lower than average velocities (?0.4% Vp; ?0.7% Vs) beneath the Bushveld Complex and parts of the Mgondi and Okwa terranes are consistent with previous studies, which attributed them to compositionally modified lithosphere resulting from Precambrian magmatic events. There is little evidence for thermally modified upper mantle beneath any of these terranes which could provide a source of uplift for the Southern African Plateau. In contrast, beneath parts of the Irumide Belt in southern and central Zambia and the Mozambique Belt in central Mozambique, deep?seated low velocity anomalies (?0.7% Vp; ?0.8% Vs) can be attributed to upper mantle extensions of the African superplume structure.
DS2002-0224
2002
Van der Merve, R.Bumby, A.J., Eriksson, P.G., Van der Merve, R., Brummer, J.J.Shear zone controlled basins in the Blouberg area, Northern Province, syn and post tectonic sedimentation relating to 2.0 Ga reactivation of Limopo Belt.Journal of African Earth Sciences, Vol. 33, No. 3-4,pp. 445-61.South AfricaStructure, tectonics - not specific to diamonds
DS2002-0432
2002
Van der Merwe, H.Eriksson, P.G., Condie, K.C., Van der Westhuizen, R., Van der Merwe, H.Late Archean superplume events: a Kaapvaal Pilbara perspectiveJournal of Geodynamics, Vol. 34, 2, pp. 207-47.AustraliaTectonics
DS1995-1958
1995
Van der Merwe, S.W.Van der Merwe, S.W.The relationship between thrusting, vertical shears, and open folds in western part of Namaqua mobile beltSouth African Journal of Geology, Vol. 98, No. 1, March pp. 68-77South AfricaTectonics, structure, Namaqua belt
DS200512-1091
2005
Van der Phuijm, B.A.Tohver, E., Van der Phuijm, B.A., Mezger, K., Scandolara, J.E., Essene, E.J.Two stage tectonic history of the SW Amazon Craton in the late Mesoproterozoic in the late Mesoproterozoic: identifying a cryptic suture zone.Precambrian Research, Vol. 137, 1-2, Apr.28, pp. 35-59.South America, BrazilParagua Craton, tectonics, geochronology
DS1996-0202
1996
Van der Ploijm, B.A.Busch, J.P., Essene, E.J., Van der Ploijm, B.A.Evolution of deep crustal normal faults: constraints from thermo barometry in the Grenville Orogen, OntarioTectonophysics, Vol. 265, No. 1/2, Nov. 5, pp. 83-100.OntarioTectonics, Thermobarometry
DS1998-0945
1998
Van der Pluijm, B.Marshak, S., Hamburger, M., Van der Pluijm, B.Tectonics of continental interiors..... Penrose Conference ReportGsa Today, Vol. 8, No. 2, Feb. pp. 23-24GlobalTectonics, Precambrian
DS200512-1092
2004
Van der Pluijm, B.Tohver, E., Van der Pluijm, B., Mezger, B., Essene, E., Scandolara, J., Rizzotto, G.Significance of the Nova Brasilandia metasedimentary belt in western Brazil: redefining the Mesoproterozoic boundary of the Amazon Craton.Tectonics, Vol. 23, 6, TC 6004 1029/2003 TC001563South America, BrazilCraton - Amazon
DS1989-0302
1989
Van der Pluijm, B.A.Craddock, J.P., Van der Pluijm, B.A.Late Paleozoic deformation of the cratonic carbonate cover of eastern North AmericaGeology, Vol. 17, No. 5, May pp. 416-419Midcontinent, Arkansas, Minnesota, WisconsinOuachita orogenic front
DS1990-0724
1990
Van der Pluijm, B.A.Howell, P.D., Van der Pluijm, B.A.Early history of the Michigan Basin: subsidence and Appalachian tectonicsGeology, Vol. 18, No. 12, December pp. 1195-1198MichiganTectonics, Midcontinent
DS1990-1496
1990
Van der Pluijm, B.A.Van der Pluijm, B.A., Johnson, R.J.E., Van der Voo, R.Early Paleozoic paleogeography and accretionary history of the NewfoundlandAppalachiansGeology, Vol. 18, No. 9, September pp. 898-901NewfoundlandTectonics -accretion, Paleogeography
DS1991-1145
1991
Van der Pluijm, B.A.Mezger, K., Van der Pluijm, B.A., Essene, E.J., Halliday, A.N.Synorogenic collapse: a perspective from the middle crust, the Proterozoic Grenville orogenScience, Vol. 254, November 1, pp. 695-698OntarioTectonics, Grenville orogeny
DS1993-1026
1993
Van der Pluijm, B.A.Mezger, K., Essene, E.J., Van der Pluijm, B.A.Uranium-lead (U-Pb) geochronology of the Grenville Orogen of Ontario and New York:constraints on ancient crustal tectonicsContributions to Mineralogy and Petrology, Vol. 114, No. 1, pp. 13-26Ontario, New YorkTectonics, Geochronology
DS1996-1458
1996
Van der Pluijm, B.A.Van der Pluijm, B.A., Catacosinos, P.A.Basement and basins of eastern North America #1Geological Society of America Special paper, No. 308, $ 50.00, pp. 204Eastern North America, Midcontinent, IllinoisBook - ad, Book - table of contents, Basement, tectonics, basins
DS1996-1459
1996
Van der Pluijm, B.A.Van der Pluijm, B.A., Catacostinos, P.A.Basement and basins of eastern North America #2Geological Society of America, SPE308, 220p. approx. $ 50.00 United StatesNorth AmericaBook - ad, Basins
DS1997-1193
1997
Van der Pluijm, B.A.Van der Pluijm, B.A., Braddocks, J.P., Harris, J.H.Paleostress in cratonic North America: implications for deformation of continental interiors.Science, Vol. 277, No. 5327, Aug. 8, pp. 794-5.United States, CanadaCraton, Deformation, tectonics
DS1998-0946
1998
Van der Pluijm, B.A.Marshak, S., Hamburger, M., Van der Pluijm, B.A.Tectonics of continental interiors. Penrose Conference reportGsa Today, Vol. 8, No. 2, Feb. pp. 23-24.GlobalContinental interior, Precambrian, Craton
DS2001-1183
2001
Van der Pluijm, B.A.Van der Pluijm, B.A., Hall, Vrolljk, Pevear, CoveyThe dating of shallow faults in the Earth's crustNature, Vol. 412, July 12, pp. 172-5.British Columbia, CordilleraStructure
DS2002-1216
2002
Van der Pluijm, B.A.Pares, J.M., Van der Pluijm, B.A.Evaluating magnetic lineations ( AMS) in deformed rocksTectonophysics, Vol. 350, No. 4, pp. 283-298.GlobalGeophysics - magnetics, Lineaments
DS2000-0937
2000
Van der Pluijn, B.A.Streepey, M.M., Van der Pluijn, B.A., Essene, E.J., HallLate Proterozoic (ca 930 Ma) extension in eastern LaurentiaGeological Society of America (GSA) Bulletin., Vol. 112, No. 10, Oct. pp. 1522-30.GlobalGrenville Province, calcium, Geochronology
DS200612-1432
2006
Van der Pluijum, B.Tohver, E., Teixeira, W., Van der Pluijum, B., Geraldes, M.C., Bettencourt, J.S., Rizzotto, G.Restored transect across the exhumed Grenville Orogen of Laurentia and Amazonia, with implications for crustal architecture.Geology, Vol. 34, 8, pp. 669-672.South America, BrazilGeochronology, Amazon Craton, tectonics
DS1989-0962
1989
Van der Plum, B.A.Mauk, J.J., Seasor, R.O., Kelly, W.C., Van der Plum, B.A.The relationship between structure and second stage copper mineralization in the White Pine district of the Midcontinent Rift, northern MichiganGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A130. AbstractMichiganMidcontinent, Tectonics
DS1860-0566
1887
Van Der Post And BukesVan Der Post And BukesImportant Public Sales of the Diamondiferous Farm Jagersfontein, No. 14.Fauresmith: Van Der Post And Bukes, 7P.Africa, South AfricaEconomics
DS1993-1643
1993
Van der Schrick, G.Van der Schrick, G.Evolving geological and mineralogical research in view of an evolving diamond market.Bulletin. Soc. Belge de Geologie, Vol. 101, No. 1, 2, pp. 3-7.GlobalDiamond, Production
DS2002-0465
2002
Van der StedtFoden, J., Song-Suck-Hwan, Turner, S., Elburg, M., Smith, P.B., Van der StedtGeochemical evolution of lithospheric mantle beneath S.E. South AustraliaChemical Geology, Vol. 182, No. 2-4, pp. 663-95.AustraliaMagmatism
DS201609-1753
2010
Van der Steen, P.Van der Steen, P.Revolution in diamond manufacturing.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 10p.GlobalHistory

Abstract: This paper examines the historical developments in diamond beneficiation technology and the impacts on the industry. The art of diamond beneficiation has given way to the application of scientific process, but at considerable capital expenditure. The shift in beneficiation methodologies has been disruptive to the traditional skills set of the industry, but evolutionary change continues and has been beneficial to the quality of the final product.
DS1997-0085
1997
Van der Steen, T.Bedford, S., Van der Steen, T.Extending the limits of subsea earthmovingWorld Diamond Conference, held Oct 7-8, 17p.GlobalTechnology - marine mining, Bulk sampling
DS1998-1515
1998
Van der Steen, T.Van der Steen, T.Production determining processes of subsea deposit removal29th. Annual Underwater Mining Institute, 1p. abstractGlobalMarine mining
DS201807-1495
2018
Van der Valk, E.A.S.Gress, M.U., Pearson, D.G., Chinn, I.L., Koornneef, J.M., Pals, A.S.M., Van der Valk, E.A.S., Davies, G.R.Episodic eclogitic diamond genesis at Jwaneng diamond mine, Botswana.Goldschmidt2018, abstract 1p.Africa, Botswanadeposit - Jwaneng

Abstract: The diamondiferous Jwaneng kimberlite cluster (~240 Ma) is located on the NW rim of the Archaean Kaapvaal Craton in central Botswana. Previous studies report eclogitic diamond formation in the late Archean (2.9 Ga) and in the Middle Proterozoic (1.5 Ga) involving different mantle and sedimentary components [1;2;3]. Here we report newly acquired Sm- Nd ages of individual eclogitic pyrope-almandine and omphacite inclusions along with their major element data and nitrogen data from the diamond hosts to re-examine Jwaneng’s diamond formation ages. The Sm-Nd isotope analyses were performed via TIMS using 1013? resistors [4]. An initial suite of three pyropealmandine and 14 omphacite inclusions yield 143Nd/144Nd from 0.51102±7 to 0.5155±5. 147Sm/144Nd vary from 0.024 to 0.469. Major element data defines two inclusion populations: (1) seven omphacites with high Mg#, high Cr# and one pyropealmandine with low-Ca define an isochron age of 1.93±0.16 Ga with ?Ndi= +3.5; (2) seven omphacites with low Mg#, low Cr# and two pyrope-almandines with low-Ca define an isochron age of 0.82±0.06 Ga with ?Ndi= +3.7. Nitrogen contents of corresponding diamond host growth zones in Group (1) are ? 50 at.ppm whereas Group (2) range between 50 to 700 at.ppm with N-aggregation > 70 %B. Additional data used to define “co-genetic” inclusion suites include Sr-isotopes and trace elements of the inclusions and carbon isotopes of the diamond hosts. Re-Os data of coexisting sulphide inclusions from the same silicate-bearing diamonds further validates the ages and indicates more periods of diamond formation at Jwaneng than previously assumed. The integrated data indicate the possibility of an extensive Paleoproterozoic diamond-forming event in southern Africa.
DS1998-0375
1998
Van der VeldenEaton, D., Ross, G., Cook, F., Van der VeldenLithoprobes vault survey: pushing the depth limit of vibroseis profilingGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A50. abstract.AlbertaGeophysics - seismics, VAULT.
DS200412-2109
2003
Van der Velden, A.White, D.J., Musacchio, G., Helmstaedt, H.H., Harrap, R.M., Thurston, P.C., Van der Velden, A., Hall, K.Images of lower crustal oceanic slab: direct evidence for tectonic accretion in the Archean western Superior Province.Geology, Vol. 31, 11, pp. 997-1000.Canada, OntarioSubduction - not specific to diamonds
DS1993-0284
1993
Van der Velden, A.J.Cook, F.A., Van der Velden, A.J.Proterozoic crustal transition beneath the Western Canada sedimentary basin.Geology, Vol. 21, No. 9, September pp. 785-788Alberta, British ColumbiaTectonics, Basin, Geophysics -seismics
DS1993-0285
1993
Van der Velden, A.J.Cook, F.A., Van der Velden, A.J.Proterozoic crustal transition beneath the Western Canada sedimentary basinGeology, Vol. 21, No. 9, Sept. oo, 785-88.Western Canada, AlbertaGeophysics - seismics, Tectonics
DS1994-1827
1994
Van der Velden, A.J.Van der Velden, A.J., Cook, F.A.Displacement of the Lewis thrust sheet in southwestern Canada: new evidence from seismic reflection data.Geology, Vol. 22, No. 9, September pp. 819-822.British ColumbiaTectonics, Geophysics -seismics
DS1995-0349
1995
Van der Velden, A.J.Cook, F.A., Van der Velden, A.J.Three dimensional crustal structure of the Purcell anticlinorium in the Cordillera of southwestern CanadaGeological Society of America (GSA), Vol. 107, June. pp.642-64.Western Canada, Cordillera, British ColumbiaGeophysics - seismics, Vibroseis, Lithoprobe
DS1996-1460
1996
Van der Velden, A.J.Van der Velden, A.J., Cook, F.A.Structure and tectonic development of the southern Rocky Mountain trenchTectonics, Vol. 15, No. 3, June pp. 517-544.British ColumbiaTectonics, Rocky Mountain Trench system
DS1997-0213
1997
Van der Velden, A.J.Cook, F.A., Van der Velden, A.J., Hall, K.W., Roberts, B.R.Upper mantle reflectors beneath the SNORCLE transect - images of the base of the lithosphere.Lithoprobe Slave/SNORCLE., pp. 58-62.MantleGeophysics - seismics
DS1998-0270
1998
Van der Velden, A.J.Cook, F.A., Van der Velden, A.J., Hall, K.W., Roberts, B.R.Tectonic delamination and subcrustal imbrication of the Precambrian lithosphere in northwestern Canada...Geology, Vol. 26, No. 9, Sept. pp. 839-42.Northwest TerritoriesLithoprobe - Slave Province, Geophysics - seismics
DS1999-0146
1999
Van der Velden, A.J.Cook, F.A., Van der Velden, A.J., Hall, K.W.Frozen subduction in Canada's Northwest Territories: Lithoprobe deep lithospheric reflection profiling....Tectonics, Vol. 18, No. 1, Feb. pp. 1-24.Northwest TerritoriesGeophysics - seismics, Lithoprobe western Canadian Shield
DS1999-0762
1999
Van der Velden, A.J.Van der Velden, A.J., Cook, F.A.Proterozoic and Cenozoic subduction complexes: a comparison of geometricfeatures.Tectonics, Vol. 18, No. 4, Aug. pp. 575-81.Cordillera, British ColumbiaTectonics - subduction, Geophysics - seismics, snorcle
DS2002-1641
2002
Van der Velden, A.J.Van der Velden, A.J., Cook, F.A.Products of 2.65 - 2.58 Ga orogenesis in the Slave Province correlated with Slave - Northern Cordillera Lithospheric Evolution ( SNORCLE) seismic reflectionCanadian Journal of Earth Science, Vol. 39,8,August pp. 1189-1200.Northwest TerritoriesGeophysics - seismic, Slave Province - tectonics, geodynamics
DS200412-0357
2004
Van der Velden, A.J.Cook, F.A., Clowes, R.M., Snyder, D.B., Van der Velden, A.J., Hall, K.W., Erdmer, P., Evenchick, C.A.Precambrian crust beneath the Mesozoic northern Canadian Cordillera discovered by lithoprobe seismic reflection profiling.Tectonics, Vol. 23, 2, TC2012 10.1029/2003TC001412Canada, Northwest Territories, British Columbia, YukonGeophysics - seismics
DS200512-0174
2005
Van der Velden, A.J.Clowes, R.M., Hanmer, P.T.C., Van der Velden, A.J.The Trans Canada crustal cross section: imaging the internal structure of our continent.GAC Annual Meeting Halifax May 15-19, Abstract 1p.CanadaGeophysics - seismics
DS200512-1118
2005
Van der Velden, A.J.Van der Velden, A.J., Cook, F.A.Relict subduction zones in Canada.Journal of Geophysical Research, Vol. 110, B8, Aug. 5, B808403 DOI 10.1029/2004 JB003333CanadaTectonics, subduction
DS200612-1465
2005
Van der Velden, A.J.Van der Velden, A.J., Cook, F.A., Drummond, B.J., Goleby, B.R.Reflections of the Neoarchean: a global perspective.Benn, K., Mareschal, J-C., Condie, K.C. Archean Geodynamics and Environments, AGU Geophysical Monograph, No. 164, pp. 255-266.MantleGeophysics - seismsics
DS201012-0264
2010
Van der Velden, A.J.Hammer, P.T.C., Clowes, R.M., Cook, F.A., Van der Velden, A.J., Vasudevan, K.The lithoprobe trans continental lithospheric cross sections: imaging the internal structure of the North American continent.Canadian Journal of Earth Sciences, Vol. 47, 5, pp. 821-957.Canada, United StatesGeophysics - seismics
DS1986-0392
1986
Van der Voo, R.Jackson, M., Van der Voo, R.A paleomagnetic estimate of the age and thermal history of the Kentland Indiana cryptoexplosion structureJournal of Geology, Vol. 94, No. 5, September pp. 713-724IndianaPaleomagnetics, Geophysics, Thermobarometry
DS1988-0723
1988
Van der Voo, R.Van der Voo, R., Johnson, R.J.E.Displaced terranes in the northern AppalachiansGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 3, February p. 239-240. abstractNewfoundlandBlank
DS1990-0729
1990
Van der Voo, R.Hurley, N.F., Van der Voo, R.Magnetostratigraphy, Late Devonian iridium anomaly, andimpacthypothesesGeology, Vol. 18, No. 4, April pp. 291-294GlobalStratigraphy, Impact hypotheses
DS1990-1496
1990
Van der Voo, R.Van der Pluijm, B.A., Johnson, R.J.E., Van der Voo, R.Early Paleozoic paleogeography and accretionary history of the NewfoundlandAppalachiansGeology, Vol. 18, No. 9, September pp. 898-901NewfoundlandTectonics -accretion, Paleogeography
DS1990-1497
1990
Van der Voo, R.Van der Voo, R.The reliability of paleomagnetic dataTectonophysics, Vol. 184, pp. 1-9United States, Canada, AfricaGeophysics, Paleomagnetics -review
DS1991-1778
1991
Van der Voo, R.Van der Voo, R., Meert, J.G.Late Proterozoic paleomagnetism and tectonic models: a critical appraisalPrecambrian Research, Vol. 53, pp. 149-163South Africa, Democratic Republic of CongoTectonics,, Proterozoic
DS1992-1352
1992
Van der Voo, R.Scotese, C.R., Van der Voo, R.A global apparent Polar Wander PathEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 88-89GlobalPaleomagnetism, tectonics, Polar Wander Path
DS1994-1163
1994
Van der Voo, R.Meet, J.G., Hargraves, R.B., Van der Voo, R., HallPaleomagnetic and 40Ar/39Ar studies of Late Kebaran intrusives in Burundi:Proterozoic supercontinentsJournal of Geology, Vol. 102, No. 6, Nov. pp. 621-638GlobalGeochronology, Proterozoic, Rodinia
DS1994-1828
1994
Van der Voo, R.Van der Voo, R.True polar wander during the middle Paleozoic?Earth and Planet. Science Letters, Vol. 122, No. 1/2, March pp. 239-244.MantlePaleomagnetism, Polar wander
DS1995-1227
1995
Van der Voo, R.Meert, J.G., Van der Voo, R.The making of Gondwana 800 - 550 MaGeological Society of America (GSA) Abstracts, Vol. 27, No. 6, abstract p. A 339.MantleGondawana
DS1995-1959
1995
Van der Voo, R.Van der Voo, R.Remagnetization and superchronsEos, Vol. 76, No. 46, Nov. 7. p.F171. Abstract.MantleGeophysics -magnetics, Paleomagnetics
DS1996-0941
1996
Van der Voo, R.Meert, J.G., Van der Voo, R.Paleomagnetic and 40 Ar- 39 Ar study of the Sinyai dolerite, Kenya:implications for Gondwana assembly.Journal of Geology, Vol. 104, pp. 131-42.KenyaTectonics, Gondwana, Kuunga Orogeny, Geochronology, argon
DS1997-0758
1997
Van der Voo, R.Meert, J.G., Van der Voo, R.The assembly of Gondwana 800- 550 MaJournal of Geodynamics, Vol. 23, No. 3-4, pp. 223-236.Tectonics
DS1998-1516
1998
Van der Voo, R.Van der Voo, R.A complex field - PaleomagnetismScience, Vol. 281, Aug. 7, pp. 79-80GlobalGeophysics, Paleomagnetism
DS1999-0443
1999
Van Der Voo, R.Marcano, M.C., Van Der Voo, R., MacNiocaill C.True polar wander during the Permo-TriassicJournal of Geodynamics, Vol. 28, No. 2-3, Sept. 2, pp. 75-95.MantleGeophysics - thermodynamics, Lithosphere
DS2002-1608
2002
Van der Voo, R.Torsvik, T.H., Van der Voo, R., Redfield, T.F.Relative hotspot motions versus True Polar WanderEarth and Planetary Science Letters, Vol. 202, 2, pp. 185-200.MantleHot spots
DS2003-0087
2003
Van der Voo, R.Bayona, G., Thomas, W.A., Van der Voo, R.Kinematics of thrust sheets within transverse zones: a structural and paleomagneticJournal of Structural Geology, Vol. 25, 8, pp. 1193-1212.Georgia, Alabama, AppalachiaStructural geology
DS200412-0115
2003
Van der Voo, R.Bayona, G., Thomas, W.A., Van der Voo, R.Kinematics of thrust sheets within transverse zones: a structural and paleomagnetic investigation in the Appalachian thrust beltJournal of Structural Geology, Vol. 25, 8, pp. 1193-1212.United States, Georgia, AlabamaStructural geology
DS200512-1119
2004
Van der Voo, R.Van der Voo, R.Paleomagnetism, oroclines and growth of the continental crust.Geology Today, Vol. 14, 12, Dec. pp. 4-9.Europe, SpainContinental drift - overview - not specific to diamonds
DS201112-0280
2011
Van der Voo, R.Dominguez, A.R., Van der Voo, R., Torsvik, T.H., Hendriks, B.W.H, Abrajevitch, A., Domeier, M., Larsen, B.T., Rousse, S.The ~270 Ma paleolatitude of Baltica and its significance for Pangea models.Geophysical Journal International, In press availableEurope, Baltic ShieldGeochronology
DS1993-1644
1993
Van der Wal, D.Van der Wal, D., Vissers, R.L.M.Uplift and emplacement of upper mantle rocks in the western MediterraneanGeology, Vol. 23, No. 12, December pp. 1119-1122.GlobalMantle rocks, Peridotites
DS1993-1645
1993
Van der Wal, D.Van der Wal, D., Vissers, R.L.M.Uplift and emplacement of upper mantle rocks in the western MediterraneanGeology, Vol. 21, No. 12, December pp. 1119-1122GlobalMantle, Tectonics
DS1995-2001
1995
Van der Wal, D.Vissers, R.L.M., Drury, M.R., Van der Wal, D.Mantle shear zones and their effect on lithosphere strength during continental breakup.Tectonophysics, Vol. 249, No. 3/4, Sept. 30, pp. 155-172.MantleTectonics, Geodynamics
DS1995-2002
1995
Van der Wal, D.Vissers, R.L.M., Platt, J.P., Van der Wal, D.Late Orogenic extension of the Betic Cordillera and Alboran Domain: alithospheric view.Tectonics, Vol. 14, No. 4, Aug. pp. 786-803.MoroccoTectonics
DS1996-1461
1996
Van der Wal, D.Van der Wal, D., Vissers, R.L.M.Structural petrology of the Ronda Peridotite: deformation historyJournal of Petrology, Vol. 37, No. 1, Feb pp. 23-44GlobalLatered Intrusion, Ronda
DS201112-0061
2011
Van der Wal, W.Barnhoorn, A., Van der Wal, W., Drury, M.R.Upper mantle viscosity and lithospheric thickness under Iceland.Journal of Geodynamics, Vol. 52, 3-4, pp. 260-270.Europe, IcelandGeophysics - seismics
DS1960-0891
1967
Van der westhuizan, H.L.Van der westhuizan, H.L.Descriptive Geology of the Kimberlite Occurrences at Bellsbank and the Frank Smith Mine Area.International Geological Congress 10TH, UNPUBL.South AfricaGeology, Mines
DS2000-0212
2000
Van der WesthuizenDe Bruiyn, H., Schoch, Van der Westhuizen, MyburghPicrite from the Katse area, Lesotho: evidence for flow differentiationJournal of African Earth Sciences, Vol. 31, No. 3-4, pp. 657-88.LesothoPicrite, Geochemistry - magma
DS2002-0432
2002
Van der Westhuizen, R.Eriksson, P.G., Condie, K.C., Van der Westhuizen, R., Van der Merwe, H.Late Archean superplume events: a Kaapvaal Pilbara perspectiveJournal of Geodynamics, Vol. 34, 2, pp. 207-47.AustraliaTectonics
DS1989-0554
1989
Van der Westhuizen, W.A.Grobler, N.J., Van der Westhuizen, W.A., Tordiffe, E.A.W.The Sodium Group, South Africa: reference section for Late Archean- early Proterozoic cratonic cover sequencesAustralian Journal of Earth Sciences, Vol. 36, pp. 41-64. Database # 17953South AfricaProterozoic, Kaapvaal Craton
DS2002-1730
2002
Van der Westhuizen, W.A.Winter, H. De La. R., Cheney, E.S., Van der Westhuizen, W.A.Sequence chronostratigraphic analysis of the Kaapvaal Province, southern Africa: responses to the 3-2 Ga plate tectonics and magmatism.11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 45.South AfricaGeochronology
DS201412-0940
2014
Van der Westhuyzen, P.Van der Westhuyzen, P., Bouwer, W., Jakins, A.Current trends in the development of new or optimization of existing diamond processing plants, with focus on beneficiation.South African Institute of Mining and Metallurgy, Vol. 114, July pp. 537-546.TechnologyDiamond processing plants
DS201805-0974
2018
van der Westhuyzen, P.Sasman, F., Deetlefs, B., van der Westhuyzen, P.Application of diamond size frequency distribution and XRT technology at a large diamond producer. The Journal of the Southern African Institute of Mining and Metallurgy, Vol. 118, Jan. pp. 1-6.Africa, South Africadiamond size frequency

Abstract: Diamond size frequency distribution (SFD) curves, combined with the associated dollar per carat per size class, play an important role in the diamond industry. Value per size class is unique for each deposit and typically varies from less than a dollar per carat to several thousands of dollars per carat for special stones. Recovery of large stone therefore contributes significantly to the bottom line of a large diamond producer. While the design of the process plant should prevent damage and possible breakage of large stones, it should also ensure adequate liberation of the finer diamonds. Innovative solutions are required to protect and recover type I and II diamonds if prominent within the resource. X-ray transmission (XRT) sorting presents the opportunity to develop flow sheet designs that incorporate a balance between exploitation of the resource and process efficiency, as well as practical capital and operating costs. This paper serves to illustrate the role and application of SFD curves in determining optimum cut-off and re-crush sizes within the flow sheet of a large diamond producer. A thorough understanding of the unique technical and economic aspects of a deposit provides the basis from where new and innovative technologies can be proposed, allowing mining companies to maintain and improve profit margins. It highlights the results of various plant trials and newly commissioned XRT sorters for larger size fractions. It also provides recommendations for future applications of XRT machines in the diamond process flow sheet.
DS200712-0220
2007
Van der Zwan, F.Davies, G.R., Wasch, L., Van der Zwan, F., Morel, M.L.A., Nebel, Van Westrenen, Pearson, HellebrandThe origin of silica rich Kaapvaal lithospheric mantle.Plates, Plumes, and Paradigms, 1p. abstract p. A205.Africa, South AfricaDeposit - Kimberley
DS200912-0807
2009
Van der Zwan, F.M.Wasch, L.J., Van der Zwan, F.M., Nebel, O., Morel, M.L.A., Hellebrand, E.W.G., Pearson, D.G., Davies, G.R.An alternative model for silica enrichment in the Kaapvaal subcontinental lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 73, 22, pp. 6894-6917.MantleMelting
DS1995-1960
1995
Van Deventer, J.Van Deventer, J.Investment in the South African minerals industryInternational Minerals and Metals Technology, pp. 19-28.South AfricaEconomics, Minerals industry -general
DS1995-1961
1995
Van Deventer, J.S.J.Van Deventer, J.S.J.Investment in the South African minerals industryInternational Minerals and Metals Tech, pp. 19-28South AfricaEconomics, Investment
DS200812-1201
2008
Van Deventer, P.W.Van Deventer, P.W., et al.Soil quality as a key success factor in sustainable rehabilitation of kimberlite mine waste.Journal of South African Institute of Mining and Metallurgy, Vol. 108, 3, pp.Africa, South AfricaMine - rehabilitation
DS200812-1202
2008
Van Deventer, P.W.Van Deventer, P.W., et al.Soil quality as a key success factor in sustainable rehabilitation of kimberlite mine waste.Journal of the South African Institute or Mining and Metallurgy, Vol. 108, 3, pp.Africa, South AfricaMining
DS201212-0745
2012
Van Dijk, M.Van Dijk, M., Kleinhans, M.G., Postma, G., Kraal, E.Contrasting morphodynamics in alluvial fans and fan deltas: effect of the Down stream boundary.Sedimentology, in press availableGlobalGeomorphology
DS201212-0746
2012
Van Dijk, M.Van Dijk, M., Kleinhans, M.G., Postma, G., Kraal, E.Contrasting morphodynamics in alluvial fans and fan deltas: effect of the Down stream boundary.Sedimentology, Vol. 59, 7, Dec. pp. 2125-2145.TechnologyGeomorphology - fans
DS201012-0811
2010
Van Dinther, Y.Van Dinther, Y., Morra, G., Funiciello, F., Faccenna, C.Role of overriding plate in the subduction process: insights from numerical models.Tectonophysics, Vol. 484, pp. 74-86.MantleSubduction
DS1982-0613
1982
Van eck, O.J.Van eck, O.J., Anderson, R.R., Cumerlato, C.L., et al.Regional Tectonics and Seismicity of Southwestern IowaIowa State Geological Survey, NUREG CR 3021, 72P. (NOVEMBER).GlobalMid-continent, Gravity, Geophysics, Thurman-redfield
DS1983-0160
1983
Van eck, O.J.Burchett, R.R., Luza, K.V., Van eck, O.J., Wilson, F.W.Seismicity and Tectonic Relationships of the Nemaha Uplift And Midcontinent Geophysical Anomaly.National Technical Information Service NUREG-CR 3117, 122P.GlobalMid-continent
DS1985-0096
1985
Van eck, O.J.Burchett, R.R., Luza, K.V., Van eck, O.J., Wilson, F.W.Seismicity and tectonic relationships of the Nemaha uplift and midcontinent geophysical anomaly (final report summary)Oklahoma Geological Survey Special Report, No. 85-2, 33pMidcontinent, Gulf Coast, OklahomaGeophysics, Tectonics
DS201808-1774
2018
Van Eeden, M.Nowicki, T., Garlick, G., Webb, K., Van Eeden, M.Estimation of commercial diamond grades based on microdiamonds: a case study of the Koidu diamond mine, Sierra Leone.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0620-9 11p.Africa, Sierra Leonedeposit - Koidu

Abstract: This paper documents the application of a microdiamond-based approach to the estimation of diamond grade in the Pipe 1 kimberlite at the Koidu mine in Sierra Leone. A geological model of Pipe 1 was constructed to represent the distribution and volume of the dominant kimberlite units within the pipe. Bulk samples, along with representative microdiamond samples, were collected from these units at surface and were used to define the ratio between microdiamond stone frequency (+212 ?m stones per kilogram) and recoverable macrodiamond grade (+1.2 mm carats per tonne; 1 carat?=?0.2 g). These ratios were applied to a comprehensive, spatially representative microdiamond sample dataset and were combined with a spatial model of country-rock xenolith dilution within the pipe to estimate +1.2 mm recoverable grades. The resource estimate was reconciled with subsequent production results in the elevation range 160 to 100 m above sea level. Production results for each of the six 10 m benches covering this elevation range were compared to the estimated average grades for these zones in the pipe. For the five cases where most of the kimberlite mass on a given bench is represented in the production data, the results show a maximum discrepancy of 6% between predicted and reported production grade with no indication of any consistent bias. This indicates that, when supported by a sound geological model and suitable microdiamond and macrodiamond data, the microdiamond-based estimation approach can provide reliable constraints on macrodiamond grade, even in the case of geologically complex bodies such as Koidu Pipe 1.
DS1970-0610
1972
Van eeden, O.R.Van eeden, O.R.The Geology of the Republic of South Africa- an Explanation of the 1: 1 Million Map.Geological Survey of South Africa, SPECIAL Publishing No. 18, 85P.South Africa, Lesotho, Botswana, Swaziland, Southern AfricaRegional Geology, Kimberley
DS1991-1657
1991
Van Eijnsberger, A.C.Stein, A., Van Eijnsberger, A.C., Barendregt, L.G.Cokriging nonstationary dataMathematical Geology, Vol. 23, No. 5, July pp. 703-720GlobalGeostatistics, Kriging
DS1991-1779
1991
Van Fossen, M.C.Van Fossen, M.C., Kent, D.V.Paleomagnetism of Late Jurassic -Early Cretaceous kimberlite dikes from Ithaca New YorkEos, Spring Meeting Program And Abstracts, Vol. 72, No. 17, April 23, p. 99GlobalPaleomagnetism, Kimberlite dikes
DS1993-1646
1993
Van Fossen, M.C.Van Fossen, M.C., Kent, D.V.A paleomagnetic study of 143 MA kimberlite dikes in central New YorkState.Geophysical Journal International, Vol. 113, No. 1, April pp. 175-185.GlobalGeophysics -dikes, Paleomagnetism
DS1996-1462
1996
Van Geest, F.Van Geest, F., Corrigan, C.Mineral policy update 1990-1994Centre for Resource Studies, 305p. $ 35.00CanadaBook -ad, Mineral policy
DS2003-0929
2003
Van Geet, M.Mees, F., Swennen, R., Van Geet, M., Jacobs, P.Applications of X ray computed tomography in the GeosciencesGeological Society of London Publ., http://bookshop.geolsoc.org.uk, SP 215, 256p. approx. $110.USGlobalBook - tomography - general interest
DS200412-1288
2003
Van Geet, M.Mees, F., Swennen, R., Van Geet, M., Jacobs, P.Applications of X ray computed tomography in the Geosciences.Geological Society of London , SP 215, 256p. approx. $110.USTechnologyBook - tomography
DS200912-0727
2009
Van Gool, A.M.St.Onge, M.R., Van Gool, A.M., Garde, A.A., Scott, D.J.Correlation of Archean and paleoproterozoic units between northeastern Canada and western Greenland: constraining the pre-collisional upper plate accretionary historyGeological Society of London, Special Publication Earth Accretionary systems in Space and Time, No. 318, pp. 193-235.Canada, Ontario, Europe, GreenlandTrans-Hudson Orogen
DS1993-1312
1993
Van Gool, J.A.M.Rivers, T., Van Gool, J.A.M., Connelly, J.N.Contrasting tectonic styles in the northern Grenville province:implications for the dynamics of orogenic frontsGeology, Vol. 21, No. 12, December pp. 1127-1130Labrador, Quebec, Ungava, OntarioTectonics, Geodynamics
DS2000-0172
2000
Van Gool, J.A.M.Connelly, J.N., Van Gool, J.A.M., Mengel, F.C.Temporal evolution of a deeply eroded orogen: the Nagssugtoqidian OrogenCanadian Journal of Earth Sciences, Vol. 37, No. 8, Aug. pp. 1121-42.GreenlandCraton - North Atlantic, Geochronology
DS2002-1642
2002
Van Gool, J.A.M.Van Gool, J.A.M., Connelly, J.N., Marker, M., Mengel, F.C.The Nagssugtoqidian Orogen of West Greenland: tectonic evolution and regional correlations from a West Greenland perspective.Canadian Journal of Earth Science, Vol.39,5, May, pp.665-86.GreenlandTectonics - Orogen, ESCOOT
DS1998-0929
1998
Van Gool. J.Manatschal, G., Ulfbeck, D., Van Gool. J.Change from thrusting to syncollisional extension at a mid-crustal level:an example from the PaleoproterozoicCanadian Journal of Earth Sciences, Vol. 35, No. 7, July pp. 802-19.GreenlandOrogen - Nagssugtoquidian, Tectonics
DS2002-1643
2002
Van Goot, J.A.M.Van Goot, J.A.M., et al.Precambrian geology of the northern Nagssugtoqidian orogen, west Greenland: mapping of the Kangaatsiaq area.Geology of Greenland Survey Bulletin, No. 191, pp. 13-23.GreenlandTectonics
DS1989-1537
1989
Van Gosen, B.S.Van Gosen, B.S., Wenrich, K.J., Thoen, W.L.Ground magnetometer survey over known and suspected breccias pipes on the Coconino Plateau, NorthwesternArizonaUnited States Geological Survey (USGS) Bulletin, No. 1683-C 31pArizonaBreccia pipes, Geophysics
DS1989-1538
1989
Van Gosen, B.S.Van Gosen, B.S., Wenrich, K.J., Thoen, W.L.Ground magnetometer surveys over known and suspected breccia pipes on the Coconino Plateau northwesternArizonaUnited States Geological Survey (USGS) Bulletin, No. B 1683-C, pp. C 1-C 31. $ 2.75Arizona, Colorado PlateauGeophysics -Magnetics, Breccia pipes
DS1993-1647
1993
Van Gosen, B.S.Van Gosen, B.S.Bibliography of geologic references (1872-1992) to the Absaroka-Beartoothstudy area in Custer and Gallatin forestsUnited States Geological Survey (USGS) Open file, No. 93-0285-A, B., 71p. 1 disc. $ 17.00MontanaBibliography, Absaroka, Beartooth
DS201112-0615
2010
Van Gosen, B.S.Long, K.R., Van Gosen, B.S., Foley, N.K., Cordier, D.The principal rare earth elements deposits of the United States - a summary of domestic deposits and a global perspective.U.S. Geological Survey, United StatesREE
DS201702-0240
2016
Van Gosen, B.S.Sengupta, D., Van Gosen, B.S.Placer type rare earth element deposits.Reviews in Economic Geology, Vol. 18, pp. 81-100.GlobalREE placers
DS1997-0311
1997
Van Groos, A.F.K.Eggenkamp, H.G.M., Van Groos, A.F.K.Chlorine stable isotopes in carbonatites: evidence for isotopic heterogeneity in the mantle. #1Chemical Geology, Vol. 140, No. 1-2, July 15, pp. 137-144.MantleCarbonatite, Geochronology
DS201312-0934
2013
Van Heck, H.Van Heck, H., Davies, J.H.Novel particle method for modelling melt generated heterogeneity in spherical mantle convection models.Goldschmidt 2013, 1p. AbstractMantleConvection
DS1998-1343
1998
Van HeerdenShirey, S.B., Carlson, R.W., Gurney, J.J., Van HeerdenRe Os isotope systematics of eclogites from Roberts Victor: Implications for diamond growth ...7th International Kimberlite Conference Abstract, pp. 808-810.South AfricaArchean tectonic processes, geochronology, Deposit - Roberts Victor
DS201112-0605
2011
Van Heerden, E.Lippmann-Pipke, J., Sherwood Lollar, B., Niedermann, S., Stroncik, N.A., Naumann, R., Van Heerden, E., Onstott, T.C.Neon identifies two billion year old fluid component in Kaapvaal Craton.Chemical Geology, Vol. 283, 3-4, pp. 287-296.Africa, South AfricaGeochronology
DS202106-0937
2021
van Heerden, E.Gomez-Arias, A., Yesares, L., Carabello, M.A., Maleke, M., Vermeulen, D., Nieto, J.M., van Heerden, E., Castillo, J.Environmental and geochemical characterization of alkaline mine wastes from Phalaborwa ( Palabora) complex, South Africa.Journal of Geochemical Exploration, Vol. 224, 106757, 13p. PdfAfrica, South Africadeposit - Palabora

Abstract: A detailed characterization of alkaline tailing ponds and waste rock dumps from Phalaborwa Igneous Complex (PIC) South Africa, has been accomplished. The study goes beyond the environmental characterization of mining wastes, offering the first insight towards the recycling of the wastes as alkaline reagent to neutralize acid industrial wastewater. To achieve these aims, tailings and waste rocks were characterized using a combination of conventional, novel and modified Acid Rock Drainage (ARD) prediction methodologies, as well as South African leachate tests, sequential extractions and pseudo-total digestions. The scarcity of Fe-sulphide minerals and the abundance of alkaline minerals indicated that PIC wastes are not ARD producers. The highest neutralization potential was found in the carbonatite rocks and East tailing samples (range between 289 and 801 kg CaCO3 eq/t). According to the National Environmental Management Waste Act (59/2008) of South Africa, tailing ponds and waste rock dumps from PIC classify as non-hazardous (Type 3 waste). The sequential extractions showed that the different fractions from most of the samples would mostly release sulphate and non-toxic elements, such as Ca, Mg, Na and K, which might be a concern if leached in high concentration. In addition, relatively high concentrations of radionuclides, such as U and Th (average of 6.7 and 36.3 mg/kg, respectively) are present in the non-labile fraction of PIC wastes, while the leachable concentrations were always below 0.006 mg/L. Among PIC wastes, East tailing would be the best option as alkaline reagent to neutralize acid wastewater because of its high neutralization potential and non-harmful leachate composition. In general, this study exposes the shortcomings in mine waste characterization, particularly for alkaline mine wastes, and introduces the assessment of potential revalorization as a novel practice in mine waste characterization that, if extended as a regular practice, would facilitate a circular economy approach to the mining industry with its consequent economic and environmental benefits.
DS1995-1962
1995
Van Heerden, L.A.Van Heerden, L.A., Boyd, S.R., Pillinger, C.T.The carbon and nitrogen isotope characteristics of Argyle and Ellendalediamonds.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 225-227.AustraliaGeochronology, Deposit -Argyle, Ellendale
DS1995-1963
1995
Van Heerden, L.A.Van Heerden, L.A., Boyd, S.R., Pillinger, C.T.The carbon and nitrogen isotope characteristics of the Argyle and Ellendalediamonds, Western Australia.International Geology Review, Vol. 37, No. 1, Jan. pp. 39-50.AustraliaGeochronology, Deposit -Argyle, Ellendale
DS1995-1964
1995
Van Heerden, L.A.Van Heerden, L.A., Boyd, S.R., Pillinger, C.T., MilledgeThe fractionation of nitrogen and carbon isotope ratios in Western Australian diamonds.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 228-230.AustraliaGeochronology, Deposit -Argyle, Ellendale
DS1995-1965
1995
Van Heerden, L.A.Van Heerden, L.A., Gurney, J.J., Deines, P.The carbon isotopic composition of harzburgite, lherzolite, websterite, eclogite paragenetic diamondsSouth. African Journal of Geology, Vol. 98, No. 2, June pp. 119-125.South Africa, BotswanaGeochronology -diamonds, Models -genetic
DS1995-1966
1995
Van Heerden, L.A.Van Heerden, L.A., Taylor, W.R., Kirkley, Gurney, BulanovaComparison of physical spectroscopic and stable isotope characteristics of Roberts Victor diamonds.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 231-232.South AfricaCathodluminescence, Deposit -Roberts Victor
DS2002-1345
2002
Van Heijst, H.J.Ritsema, J., Rivera, L.A., Komatitsch, D., Tromp, J., Van Heijst, H.J.Effects of crust and mantle heterogeneity on PP/P and SS/S amplitude ratiosGeophysical Research Letters, Vol. 29,10,May15,pp.72-MantleGeophysics
DS200912-0630
2009
Van Heijst, H.J.Ritsema, J., Van Heijst, H.J., Woodhouse, J.H., deuss, A.Long period body wave traveltimes through the crust: implications for crustal corrections and seismic tomography.Geophysical Journal International, Vol. 179, 2, Nov. pp. 1255-1261.MantleGeophysics - seismics
DS201412-0119
2014
van Heijst, H.J.Chang, S-J., Ferreira, A.M.G., Ritsema, J., van Heijst, H.J., Woodhouse, J.H.Global radially anisotropic mantle structure from multiple datasets: a review, current challenges, and outlook.Tectonophysics, Vol. 617, pp. 1-19.MantleTomography
DS201212-0714
2012
Van Hinsberg, V.J.Szilas, K., Naeraa, T., Schersten, A., Stendal, H., Frei, R., Van Hinsberg, V.J., Kokfelt, T.F., Rosing, M.T.Origin of Mesoarchean arc related rocks with boninite-komatiite affinities from southern West Greenland.Lithos, in pressEurope, GreenlandBoninites
DS201412-0909
2014
Van Hinsberg, V.J.Szilas, K.,Van Hinsberg, V.J., Creaser, R.A., Kisters, A.F.M.The geochemical composition of serpentinites in the Mesoarchean Tartoq Group, SW Greenland: harzburgite cumulates or melt-modified mantle?Lithos, Vol. 198-199, pp. 103-116.Europe, GreenlandMelting
DS202002-0163
2019
van Hinsberg, V.J.Beard, C.D., van Hinsberg, V.J., Stix, J., Wilke, M.Clinopyroxene melt trace element partitioning in sodic alkaline magmas.Journal of Petrology, in press available 92p. PdfEurope, Canary IslandsREE

Abstract: Clinopyroxene is a key fractionating phase in alkaline magmatic systems, but its impact on metal enrichment processes, and the formation of REE + HFSE mineralisation in particular, is not well understood. To constrain the control of clinopyroxene on REE + HFSE behaviour in sodic (per)alkaline magmas, a series of internally heated pressure vessel experiments was performed to determine clinopyroxene-melt element partitioning systematics. Synthetic tephriphonolite to phonolite compositions were run H2O-saturated at 200?MPa, 650-825?C with oxygen fugacity buffered to log f O2 ? ?QFM + 1 or log f O2 ? ?QFM +5. Clinopyroxene-glass pairs from basanitic to phonolitic fall deposits from Tenerife, Canary Islands, were also measured to complement our experimentally-derived data set. The REE partition coefficients are 0.3-53, typically 2-6, with minima for high-aegirine clinopyroxene. Diopside-rich clinopyroxenes (Aeg5-25) prefer the MREE and have high REE partition coefficients (DEuup to 53, DSmup to 47). As clinopyroxene becomes more Na- and less Ca-rich (Aeg25-50), REE incorporation becomes less favourable, and both the VIM1 and VIIIM2 sites expand (to 0.79 Å and 1.12 Å), increasing DLREE/DMREE. Above Aeg50 both M sites shrink slightly and HREE (VIri? 0.9 Å ? Y) partition strongly onto the VIM1 site, consistent with a reduced charge penalty for REE3+ ? Fe3+ substitution. Our data, complemented with an extensive literature database, constrain an empirical model that predicts trace element partition coefficients between clinopyroxene and silicate melt using only mineral major element compositions, temperature and pressure as input. The model is calibrated for use over a wide compositional range and can be used to interrogate clinopyroxene from a variety of natural systems to determine the trace element concentrations in their source melts, or to forward model the trace element evolution of tholeiitic mafic to evolved peralkaline magmatic systems.
DS201801-0074
2017
van Hinsbergen, D.J.van Hinsbergen, D.J., Lippert, P.C., Huang, W.Unfeasible subduction?Nature Geoscience, Vol. 10, 12, pp. 878-9.Mantlesubduction
DS201012-0810
2010
Van Hinsbergen, D.J.J.Van der Meer, D.G., Spakman, W., Van Hinsbergen, D.J.J., Amaru, M.L., Torsvik, T.H.Towards absolute plate motions constrained by lower mantle slab remnants.Nature Geoscience, Vol. 3, Jan. pp. 36-40.MantleTectonics, Pangea
DS201112-1074
2011
Van Hinsbergen, D.J.J.Van Hinsbergen, D.J.J., Buiter, S.J.H., Torsvik, T.H., Gaina, C., Webb, S.J.The formation and evolution of Africa from the Archean to Present; introduction.The Formation and Evolution of Africa: A synopsis of 3.8 Ga of Earth History, Geol. Soc. London Special Publ., 357, pp. 1-8.AfricaHistory
DS201112-1075
2011
Van Hinsbergen, D.J.J.Van Hinsbergen, D.J.J., Steinberger, B., Doubrovine, P.V., Gassmuller, R.Acceleration and deceleration of India-Asia convergence since the Cretaceous: roles of mantle plumes and continental collision.Journal of Geophysical Research, in press availableIndia, China, AsiaHotspots
DS201811-2616
2018
van Hinsbergen, D.J.J.van der Meer, D.G., van Hinsbergen, D.J.J., Spakman, W.Atlas of the underworld: slab remnants in the mantle, their sinking history, and a new outlook on lower mantle viscosity.Tectonophysics, Vol. 773, 1, pp. 309-448.Mantlegeophysics - seismic

Abstract: Across the entire mantle we interpret 94 positive seismic wave-speed anomalies as subducted lithosphere and associate these slabs with their geological record. We document this as the Atlas of the Underworld, also accessible online at www.atlas-of-the-underworld.org, a compilation comprising subduction systems active in the past ~ 300 Myr. Deeper slabs are correlated to older geological records, assuming no relative horizontal motions between adjacent slabs following break-off, using knowledge of global plate circuits, but without assuming a mantle reference frame. The longest actively subducting slabs identified reach the depth of ~ 2500 km and some slabs have impinged on Large Low Shear Velocity Provinces in the deepest mantle. Anomously fast sinking of some slabs occurs in regions affected by long-term plume rising. We conclude that slab remnants eventually sink from the upper mantle to the core-mantle boundary. The range in subduction-age versus - depth in the lower mantle is largely inherited from the upper mantle history of subduction. We find a significant depth variation in average sinking speed of slabs. At the top of the lower mantle average slab sinking speeds are between 10 and 40 mm/yr, followed by a deceleration to 10-15 mm/yr down to depths around 1600-1700 km. In this interval, in situ time-stationary sinking rates suggest deceleration from 20 to 30 mm/yr to 4-8 mm/yr, increasing to 12-15 mm/yr below 2000 km. This corroborates the existence of a slab deceleration zone but we do not observe long-term (> 60 My) slab stagnation, excluding long-term stagnation due to compositional effects. Conversion of slab sinking profiles to viscosity profiles shows the general trend that mantle viscosity increases in the slab deceleration zone below which viscosity slowly decreases in the deep mantle. This is at variance with most published viscosity profiles that are derived from different observations, but agrees qualitatively with recent viscosity profiles suggested from material experiments.
DS201902-0328
2018
van Hinsbergen, D.J.J.Van der Meer, D.G., van Hinsbergen, D.J.J., Spakman, W.Atlas of the underworld: slab remnants in the mantle, their sinking history, and a new outlook on lower mantle viscosity.Tectonophysics, Vol. 723, 1, pp. 309-448.Mantlesubduction

Abstract: Across the entire mantle we interpret 94 positive seismic wave-speed anomalies as subducted lithosphere and associate these slabs with their geological record. We document this as the Atlas of the Underworld, also accessible online at www.atlas-of-the-underworld.org, a compilation comprising subduction systems active in the past ~ 300 Myr. Deeper slabs are correlated to older geological records, assuming no relative horizontal motions between adjacent slabs following break-off, using knowledge of global plate circuits, but without assuming a mantle reference frame. The longest actively subducting slabs identified reach the depth of ~ 2500 km and some slabs have impinged on Large Low Shear Velocity Provinces in the deepest mantle. Anomously fast sinking of some slabs occurs in regions affected by long-term plume rising. We conclude that slab remnants eventually sink from the upper mantle to the core-mantle boundary. The range in subduction-age versus - depth in the lower mantle is largely inherited from the upper mantle history of subduction. We find a significant depth variation in average sinking speed of slabs. At the top of the lower mantle average slab sinking speeds are between 10 and 40 mm/yr, followed by a deceleration to 10-15 mm/yr down to depths around 1600-1700 km. In this interval, in situ time-stationary sinking rates suggest deceleration from 20 to 30 mm/yr to 4-8 mm/yr, increasing to 12-15 mm/yr below 2000 km. This corroborates the existence of a slab deceleration zone but we do not observe long-term (> 60 My) slab stagnation, excluding long-term stagnation due to compositional effects. Conversion of slab sinking profiles to viscosity profiles shows the general trend that mantle viscosity increases in the slab deceleration zone below which viscosity slowly decreases in the deep mantle. This is at variance with most published viscosity profiles that are derived from different observations, but agrees qualitatively with recent viscosity profiles suggested from material experiments.
DS201910-2306
2019
Van Hinsbergen, D.J.J.Van Hinsbergen, D.J.J., Torsvik, T.H., Schmid, S.M., Matenco, L.C., Maffione, M., Vissers, R.L.M., Gurer, D., Spakman, W.Orogenic architecture of the Mediterranean region and kinematic reconstruction of its tectonic evolution since the Triassic. AtriaGondwana Research, in press available 427p.Europecraton

Abstract: The basins and orogens of the Mediterranean region ultimately result from the opening of oceans during the early break-up of Pangea since the Triassic, and their subsequent destruction by subduction accommodating convergence between the African and Eurasian Plates since the Jurassic. The region has been the cradle for the development of geodynamic concepts that link crustal evolution to continental break-up, oceanic and continental subduction, and mantle dynamics in general. The development of such concepts requires a first-order understanding of the kinematic evolution of the region for which a multitude of reconstructions have previously been proposed. In this paper, we use advances made in kinematic restoration software in the last decade with a systematic reconstruction protocol for developing a more quantitative restoration of the Mediterranean region for the last 240 million years. This restoration is constructed for the first time with the GPlates plate reconstruction software and uses a systematic reconstruction protocol that limits input data to marine magnetic anomaly reconstructions of ocean basins, structural geological constraints quantifying timing, direction, and magnitude of tectonic motion, and tests and iterations against paleomagnetic data. This approach leads to a reconstruction that is reproducible, and updatable with future constraints. We first review constraints on the opening history of the Atlantic (and Red Sea) oceans and the Bay of Biscay. We then provide a comprehensive overview of the architecture of the Mediterranean orogens, from the Pyrenees and Betic-Rif orogen in the west to the Caucasus in the east and identify structural geological constraints on tectonic motions. We subsequently analyze a newly constructed database of some 2300 published paleomagnetic sites from the Mediterranean region and test the reconstruction against these constraints. We provide the reconstruction in the form of 12 maps being snapshots from 240 to 0 Ma, outline the main features in each time-slice, and identify differences from previous reconstructions, which are discussed in the final section.
DS201212-0071
2012
Van Hinsbergen, J.J.Biggin, A.J., Steinberger, B., Aubert, J., Suttle, N., Holme, R., Torsvik, H., Van der Meer, D.G., Van Hinsbergen, J.J.Possible links between long term geomagnetic variations and whole mantle convection processes.Nature Geoscience, Vol. 5, pp. 526-533.MantleConvection
DS200512-0602
2004
Van Horn, S.Law, E., Bear, S., Van Horn, S.Petrographic evidence of an instant freeze of kimberlite diatreme.Geological Society of America Northeastern Meeting ABSTRACTS, Vol. 36, 2, p. 71.United States, PennsylvaniaTanoma kimberlite dykes, phreatomagmatism
DS200712-0188
2007
Van Hunden, J.Cizkova, H., Van Hunden, J., Van den Berg, A.Stress distribution within subducting slabs and their deformation in the transition zone.Physics of the Earth and Planetary Interiors, Vol. 161, 3-4, pp. 202-214.MantleSubduction
DS2001-1184
2001
Van Hunen, J.Van Hunen, J., VandenBerg, A.P., Vlaar, N.J.Latent heat effects of the major mantle phase transitions on low angle subduction.Earth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 125-35.MantleSubduction
DS2002-0344
2002
Van Hunen, J.Czkova, H., Van Hunen, J., Van denberg, A.P., Vlaar, N.J.The influence of rheological weakening and yield stress on the interaction of slabs with the 670 km discontinuity.Earth and Planetary Science Letters, Vol.199,3-4,pp.447-57.MantleBoundary, Subduction
DS2002-1644
2002
Van Hunen, J.Van Hunen, J., Van den Berg, A.P., Vlaar, N.J.The impact of the South American plate motion and the Nazca Ridge subduction on the flat subduction below south Peru.Geophysical Research Letters, Vol. 29, 14, DOI 10.1029/2001GL014004PeruTectonics - subduction
DS2003-0606
2003
Van Hunen, J.Huang, J., Zhong, S., Van Hunen, J.Controls on sublithospheric small scale convectionJournal of Geophysical Research, Vol. 108, B8,Aug. 30., 2405 10.1029/2003JB002456MantleGeophysics - seismics
DS200412-0855
2003
Van Hunen, J.Huang, J., Zhong, S., Van Hunen, J.Controls on sublithospheric small scale convection.Journal of Geophysical Research, Vol. 108, B8,Aug. 30., 2405 10.1029/2003 JB002456MantleGeophysics - seismics
DS200512-1120
2004
Van Hunen, J.Van Hunen, J., Van den Berg, A.P., Vlaar, N.J.Various mechanisms to induce present day shallow flat subduction and implications for the younger Earth: a numerical parameter study.Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 159-194.MantleSubduction
DS200812-1203
2008
Van Hunen, J.Van Hunen, J., Van den Berg, A.P.Plate tectonics on the Early Earth: limitations imposed by strength and bouyancy of subducted lithosphere.Lithos, Vol. 103, 1-2, pp. 217-235.MantleTectonics
DS200812-1204
2008
Van Hunen, J.Van Hunen, J., Van Kekn, P.E., Hynes, A., Davies, G.F.Tectonics of early Earth: some geodynamic considerations.Geological Society of America Special Paper, 440, pp. 157-198.MantleTectonics
DS201012-0812
2010
Van Hunen, J.Van Wijk, J.W., Baldridge, W.S., Van Hunen, J., Goes, S., Aster, R., Coblentz, D.D., Grand, S.P., Ni, J.Small scale convection at the edge of the Colorado Plateau: implications for topography, magmatism, and evolution of Proterozoic lithosphere.Geology, Vol. 38, 7, pp. 611-614.United States, Colorado PlateauMagmatism
DS201212-0397
2012
Van Hunen, J.Laurie, A., Stevens, G., Van Hunen, J.The end of continental growth by TTG magmatism.Terra Nova, In press availableMantleSubduction
DS201212-0499
2012
Van Hunen, J.Moyen, J-F., Van Hunen, J.Short term episodicity of Archean plate tectonics.Geology, Vol. 40, 5, pp. 451-454.MantleGeodynamics
DS201212-0747
2012
Van Hunen, J.Van Hunen, J., Moyen, J-F.Archean subduction: fact or fiction?Annual Review of Earth and Planetary Sciences, Vol. 40, pp. 195-219.MantlePlate tectonics, geodynamics
DS201312-0082
2013
van Hunen, J.Bianco, T.A., Ito, G., van Hunen, J., Mahoney, J.J., Ballmer, M.D.Geochemical variations at ridge centered hotspots caused by variable melting of a veined mantle plume.Earth and Planetary Science Letters, Vol. 371-372, pp. 191-202.GlobalGeochemisty
DS201312-0935
2013
Van Hunen, J.Van Hunen, J., Moyen, J-F.Archean subduction Fact or Fiction?Annual Review of Earth and Planetary Sciences, Vol. 40, pp. 195-216.MantleSubduction
DS201412-0959
2014
Van Hunen, J.Wang, H., Van Hunen, J., Pearson, D.G., Allen, M.B.Craton stability and longevity: the roles of composition- dependent rheology and buoyancy.Earth and Planetary Science Letters, Vol. 391, 1, pp. 224-233.MantleCraton
DS201702-0232
2016
van Hunen, J.Plethean, J.J.J., Kalnins, L.M., van Hunen, J., Biffi, P.G., Davies, R.J., McCaffrey, K.J.W.Madagascar's escape from Africa: a resolution plate reconstruction for the Western Somali Basin and for supercontinent dispersal.Geochemistry, Geophysics, Geosystems: G3, Vol. 17, 2, pp. 5036-5055.Africa, MadagascarTectonics

Abstract: Accurate reconstructions of the dispersal of supercontinent blocks are essential for testing continental breakup models. Here, we provide a new plate tectonic reconstruction of the opening of the Western Somali Basin during the breakup of East and West Gondwana. The model is constrained by a new comprehensive set of spreading lineaments, detected in this heavily sedimented basin using a novel technique based on directional derivatives of free-air gravity anomalies. Vertical gravity gradient and free-air gravity anomaly maps also enable the detection of extinct mid-ocean ridge segments, which can be directly compared to several previous ocean magnetic anomaly interpretations of the Western Somali Basin. The best matching interpretations have basin symmetry around the M0 anomaly; these are then used to temporally constrain our plate tectonic reconstruction. The reconstruction supports a tight fit for Gondwana fragments prior to breakup, and predicts that the continent-ocean transform margin lies along the Rovuma Basin, not along the Davie Fracture Zone (DFZ) as commonly thought. According to our reconstruction, the DFZ represents a major ocean-ocean fracture zone formed by the coalescence of several smaller fracture zones during evolving plate motions as Madagascar drifted southwards, and offshore Tanzania is an obliquely rifted, rather than transform, margin. New seismic reflection evidence for oceanic crust inboard of the DFZ strongly supports these conclusions. Our results provide important new constraints on the still enigmatic driving mechanism of continental rifting, the nature of the lithosphere in the Western Somali Basin, and its resource potential.
DS201702-0251
2017
van Hunen, J.Wang, H., van Hunen, J., Pearson, D.G.Making Archean cratonic roots by lateral compression: a two stage thickening and stabilization model.Tectonophysics, in press available, 10p.MantleCraton, tectonics

Abstract: Archean tectonics was capable of producing virtually indestructible cratonic mantle lithosphere, but the dominant mechanism of this process remains a topic of considerable discussion. Recent geophysical and petrological studies have refuelled the debate by suggesting that thickening and associated vertical movement of the cratonic mantle lithosphere after its formation are essential ingredients of the cratonization process. Here we present a geodynamical study that focuses on how the thick stable cratonic lithospheric roots can be made in a thermally evolving mantle. Our numerical experiments explore the viability of a cratonization process in which depleted mantle lithosphere grows via lateral compression into a > 200-km thick, stable cratonic root and on what timescales this may happen. Successful scenarios for craton formation, within the bounds of our models, are found to be composed of two stages: an initial phase of tectonic shortening and a later phase of gravitational self-thickening. The initial tectonic shortening of previously depleted mantle material is essential to initiate the cratonization process, while the subsequent gravitational self-thickening contributes to a second thickening phase that is comparable in magnitude to the initial tectonic phase. Our results show that a combination of intrinsic compositional buoyancy of the cratonic root, rapid cooling of the root after shortening, and the long-term secular cooling of the mantle prevents a Rayleigh-Taylor type collapse, and will stabilize the thick cratonic root for future preservation. This two-stage thickening model provides a geodynamically viable cratonization scenario that is consistent with petrological and geophysical constraints.
DS201704-0615
2017
van Hunen, J.Agrusta, R., Goes, S., van Hunen, J.Subducting slab transition zone interaction: stagnation, penetration and mode switches.Earth and Planetary Science Letters, Vol. 464, pp. 10-23.MantleSubduction

Abstract: Seismic tomography shows that subducting slabs can either sink straight into the lower mantle, or lie down in the mantle transition zone. Moreover, some slabs seem to have changed mode from stagnation to penetration or vice versa. We investigate the dynamic controls on these modes and particularly the transition between them using 2D self-consistent thermo-mechanical subduction models. Our models confirm that the ability of the trench to move is key for slab flattening in the transition zone. Over a wide range of plausible Clapeyron slopes and viscosity jumps at the base of the transition zone, hot young slabs (25 Myr in our models) are most likely to penetrate, while cold old slabs (150 Myr) drive more trench motion and tend to stagnate. Several mechanisms are able to induce penetrating slabs to stagnate: ageing of the subducting plate, decreasing upper plate forcing, and increasing Clapeyron slope (e.g. due to the arrival of a more hydrated slab). Getting stagnating slabs to penetrate is more difficult. It can be accomplished by an instantaneous change in the forcing of the upper plate from free to motionless, or a sudden decrease in the Clapeyron slope. A rapid change in plate age at the trench from old to young cannot easily induce penetration. On Earth, ageing of the subducting plate (with accompanying upper plate rifting) may be the most common mechanism for causing slab stagnation, while strong changes in upper plate forcing appear required for triggering slab penetration.
DS201707-1329
2017
van Hunen, J.Goes, S., Agrusta, R., van Hunen, J., Garel, F.Subduction - transition zone interaction: a review.Geosphere, Vol. 13, 3, pp. 644-8.Mantlesubduction

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20–50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of –1 to –2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100–300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS201707-1380
2016
van Hunen, J.Wang, H., van Hunen, J., Pearson, D.G.Making Archean cratonic roots by lateral compression: a two stage thickening and stabilization model.Tectonophysics, in press availableMantlecraton

Abstract: Archean tectonics was capable of producing virtually indestructible cratonic mantle lithosphere, but the dominant mechanism of this process remains a topic of considerable discussion. Recent geophysical and petrological studies have refuelled the debate by suggesting that thickening and associated vertical movement of the cratonic mantle lithosphere after its formation are essential ingredients of the cratonization process. Here we present a geodynamical study that focuses on how the thick stable cratonic lithospheric roots can be made in a thermally evolving mantle. Our numerical experiments explore the viability of a cratonization process in which depleted mantle lithosphere grows via lateral compression into a > 200-km thick, stable cratonic root and on what timescales this may happen. Successful scenarios for craton formation, within the bounds of our models, are found to be composed of two stages: an initial phase of tectonic shortening and a later phase of gravitational self-thickening. The initial tectonic shortening of previously depleted mantle material is essential to initiate the cratonization process, while the subsequent gravitational self-thickening contributes to a second thickening phase that is comparable in magnitude to the initial tectonic phase. Our results show that a combination of intrinsic compositional buoyancy of the cratonic root, rapid cooling of the root after shortening, and the long-term secular cooling of the mantle prevents a Rayleigh-Taylor type collapse, and will stabilize the thick cratonic root for future preservation. This two-stage thickening model provides a geodynamically viable cratonization scenario that is consistent with petrological and geophysical constraints.
DS201709-2027
2017
van Hunen, J.Magni, V., Allen, M.B., van Hunen, J., Bouihol, P.Continental underplating after slab break-off.Earth and Planetary Science Letters, Vol. 474, pp. 59-67.Mantle, India-Eurasiasubduction

Abstract: We present three-dimensional numerical models to investigate the dynamics of continental collision, and in particular what happens to the subducted continental lithosphere after oceanic slab break-off. We find that in some scenarios the subducting continental lithosphere underthrusts the overriding plate not immediately after it enters the trench, but after oceanic slab break-off. In this case, the continental plate first subducts with a steep angle and then, after the slab breaks off at depth, it rises back towards the surface and flattens below the overriding plate, forming a thick horizontal layer of continental crust that extends for about 200 km beyond the suture. This type of behaviour depends on the width of the oceanic plate marginal to the collision zone: wide oceanic margins promote continental underplating and marginal back-arc basins; narrow margins do not show such underplating unless a far field force is applied. Our models show that, as the subducted continental lithosphere rises, the mantle wedge progressively migrates away from the suture and the continental crust heats up, reaching temperatures >900?°C. This heating might lead to crustal melting, and resultant magmatism. We observe a sharp peak in the overriding plate rock uplift right after the occurrence of slab break-off. Afterwards, during underplating, the maximum rock uplift is smaller, but the affected area is much wider (up to 350 km). These results can be used to explain the dynamics that led to the present-day crustal configuration of the India–Eurasia collision zone and its consequences for the regional tectonic and magmatic evolution.
DS201711-2513
2017
van Hunen, J.Freeburn, R., Bouilhol, P., Maunder, B., Magni, V., van Hunen, J.Numerical models of the magmatic processes induced by slab breakoff.Earth and Planetary Science Letters, Vol. 478, pp. 203-213.Mantlesubduction

Abstract: After the onset of continental collision, magmatism often persists for tens of millions of years, albeit with a different composition, in reduced volumes, and with a more episodic nature and more widespread spatial distribution, compared to normal arc magmatism. Kinematic modelling studies have suggested that slab breakoff can account for this post-collisional magmatism through the formation of a slab window and subsequent heating of the overriding plate and decompression melting of upwelling asthenosphere, particularly if breakoff occurs at depths shallower than the overriding plate. To constrain the nature of any melting and the geodynamic conditions required, we numerically model the collision of two continental plates following a period of oceanic subduction. A thermodynamic database is used to determine the (de)hydration reactions and occurrence of melt throughout this process. We investigate melting conditions within a parameter space designed to generate a wide range of breakoff depths, timings and collisional styles. Under most circumstances, slab breakoff occurs deeper than the depth extent of the overriding plate; too deep to generate any decompressional melting of dry upwelling asthenosphere or thermal perturbation within the overriding plate. Even if slab breakoff is very shallow, the hot mantle inflow into the slab window is not sustained long enough to sufficiently heat the hydrated overriding plate to cause significant magmatism. Instead, for relatively fast, shallow breakoff we observe melting of asthenosphere above the detached slab through the release of water from the tip of the heating detached slab. Melting of the subducted continental crust during necking and breakoff is a more common feature and may be a more reliable indicator of the occurrence of breakoff. We suggest that magmatism from slab breakoff alone is unable to explain several of the characteristics of post-collisional magmatism, and that additional geodynamical processes need to be considered when interpreting magmatic observations.
DS201801-0078
2017
van Hunen, J.Wang, H., van Hunen, J., Pearson, D.G.Making Archean cratonic roots by lateral compression: a two stage thickening and stabilization model.Tectonophysics, in press available, 10p.Mantlecraton

Abstract: Making Archean cratonic roots by lateral compression: a two stage thickening and stabilization model.
DS201901-0035
2017
van Hunen, J.Goes, S., Agrusta, R., van Hunen, J., Garel, F.Subduction - transition zone interaction: a review.Geosphere, Vol. 13, 3, pp. 644-664.Mantlesubduction

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20-50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of -1 to -2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100-300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS201901-0085
2018
van Hunen, J.Wang, H., van Hunen, J., Pearson, D.G.Making Archean cratonic roots by lateral compression: a two stage thickening and stabilization model.Tectonophysics, Vol. 746, pp. 562-571.Mantlemelting

Abstract: Archean tectonics was capable of producing virtually indestructible cratonic mantle lithosphere, but the dominant mechanism of this process remains a topic of considerable discussion. Recent geophysical and petrological studies have refuelled the debate by suggesting that thickening and associated vertical movement of the cratonic mantle lithosphere after its formation are essential ingredients of the cratonization process. Here we present a geodynamical study that focuses on how the thick stable cratonic lithospheric roots can be made in a thermally evolving mantle. Our numerical experiments explore the viability of a cratonization process in which depleted mantle lithosphere grows via lateral compression into a > 200-km thick, stable cratonic root and on what timescales this may happen. Successful scenarios for craton formation, within the bounds of our models, are found to be composed of two stages: an initial phase of tectonic shortening and a later phase of gravitational self-thickening. The initial tectonic shortening of previously depleted mantle material is essential to initiate the cratonization process, while the subsequent gravitational self-thickening contributes to a second thickening phase that is comparable in magnitude to the initial tectonic phase. Our results show that a combination of intrinsic compositional buoyancy of the cratonic root, rapid cooling of the root after shortening, and the long-term secular cooling of the mantle prevents a Rayleigh-Taylor type collapse, and will stabilize the thick cratonic root for future preservation. This two-stage thickening model provides a geodynamically viable cratonization scenario that is consistent with petrological and geophysical constraints.
DS202109-1484
2021
van Hunen, J.Pearson, D.G., Scott, J.M., Liu, J., Schaeffer, A., Wang, L.H., van Hunen, J., Szilas, K., Chacko, T., Kelemen, P.B. Deep continental roots and cratons.Nature, Vol. 596, pp. 199-210. pdfGlobalcratons

Abstract: The formation and preservation of cratons-the oldest parts of the continents, comprising over 60 per cent of the continental landmass-remains an enduring problem. Key to craton development is how and when the thick strong mantle roots that underlie these regions formed and evolved. Peridotite melting residues forming cratonic lithospheric roots mostly originated via relatively low-pressure melting and were subsequently transported to greater depth by thickening produced by lateral accretion and compression. The longest-lived cratons were assembled during Mesoarchean and Palaeoproterozoic times, creating the stable mantle roots 150 to 250 kilometres thick that are critical to preserving Earth’s early continents and central to defining the cratons, although we extend the definition of cratons to include extensive regions of long-stable Mesoproterozoic crust also underpinned by thick lithospheric roots. The production of widespread thick and strong lithosphere via the process of orogenic thickening, possibly in several cycles, was fundamental to the eventual emergence of extensive continental landmasses-the cratons.
DS201610-1840
2016
van Kann, F.Aravanis, T., Chen, J., Fuechsle, M., Grujic, M., Johnston, P., Kok, Y., Magaraggia, R., Mann, A., Mann, L., McIntoshm S., Rheinberger, G., Saxey, D., Smalley, M., van Kann, F., Walker, G., Winterflood, J.VK1 tm - a next generation airborne gravity gradiometer.ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 5p.TechnologyGradiometer

Abstract: The minerals exploration industry’s demand for a highly precise airborne gravity gradiometer has driven development of the VK1TM Airborne Gravity Gradiometer, a collaborative effort by Rio Tinto and the University of Western Australia. VK1TM aims to provide gravity gradient data with lower uncertainty and higher spatial resolution than current commercial systems. In the recent years of VK1TM development, there have been significant improvements in hardware, signal processing and data processing which have combined to result in a complete AGG system that is approaching competitive survey-ready status. This paper focuses on recent improvements. Milestone-achieving data from recent lab-based and moving-platform trials will be presented and discussed, along with details of some advanced data processing techniques that are required to make the most use of the data.
DS1994-0451
1994
Van Kann, F.J.Dransfield, M.H., Buckingham, M.J., Van Kann, F.J.Lithological mapping by correlating magnetic and gravity gradient airbornemeasurementsExploration Geophysics, Australian Bulletin, Vol. 25, No. 1, March pp. 25-30GlobalGeophysics -gravity, Lithology
DS1994-1864
1994
Van Keken, .E.Vlaar, N.J., Van Keken, .E., Van den Berg, A.P.Cooling of the Earth in the Archean: consequences of pressure release melting in a hotter mantleEarth and Planetary Science Letters, Vol. 121, No. 1-2, January pp. 1-18MantleArchean, Melting
DS1997-1194
1997
Van Keken, P.Van Keken, P.Evolution of starting mantle plumes: a comparison between numerical and laboratory models.Earth and Planetary Science Letters, Vol. 148, No. 1-2, Apr. 1, pp. 1-12.MantlePlumes
DS2001-1185
2001
Van Keken, P.Van Keken, P.Cylindrical scaling for dynamical cooling models of the EarthPhysics Earth Plan. International, Vol. 124, No. 1-2, pp. 119-30.MantleConvection, modeling, heat flow
DS1994-1829
1994
Van Keken, P.E.Van Keken, P.E., et al.Implications for mantle dynamics from the high melting temperature ofperovskite.Science, Vol. 264, No. 5164, June 3, pp. 1437-1438.MantlePerovskite
DS1994-1865
1994
Van Keken, P.E.Vlaar, N.J., Van Keken, P.E., Van den Berg, A.P.Cooling of the earth in thr Archean: consequences of pressure release melting in a hotter mantle.Earth and Planetary Science Letters, Vol. 121, No. 1/2, January pp. 1-18.MantleArchean, Hot spots
DS1998-0071
1998
Van Keken, P.E.Ballentine, C.J., Van Keken, P.E.Dynamical models of mantle 3 He 4 He evolutionMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 104-5.MantleGeodynamics, Helium, Degassing, volatiles
DS1998-1517
1998
Van Keken, P.E.Van Keken, P.E., Ballentine, C.J.Whole mantle versus layered mantle convection and the role of high viscosity lower mantle in terrestrial vol.Earth and Planetary Science Letters, Vol. 156, No. 1-2, Mar. 15, pp. 19-32.MantleConvection, melt, Volatile evolution
DS1999-0763
1999
Van Keken, P.E.Van Keken, P.E., Ballentine, C.J.Dynamical models of mantle volatile evolution and the role of phase transitions and temperature dependent...Journal of Geophysical Research, Vol. 104, No. 4, Apr. 10, pp. 7137-52.MantleRheology, Geodynamics
DS2001-0762
2001
Van Keken, P.E.McNamara, A.K., Karato, S.I., Van Keken, P.E.Localization of dislocation creep in the lower mantle: implications for origin of seismic anisotropy.Earth and Planetary Science Letters, Vol. 191, No. 2, pp. 85-99.MantleGeophysics - seismics
DS2001-1297
2001
Van Keken, P.E.Zegers, T., Van Keken, P.E.Middle Archean continent formation by crustal delaminationGeology, Vol. 29, No. 12, Dec. pp. 1083-6.AustraliaPilbara Craton, eclogite
DS2002-0098
2002
Van Keken, P.E.Ballentine, C.J., Van Keken, P.E., Porcelli, D., Hauri, E.H.Numerical models, geochemistry and the zero-paradox noble gas mantlePhilosophical Transactions, Royal Society of London Series A Mathematical, Vol.1800, pp. 2611-32.MantleGeochemistry - model
DS2002-1036
2002
Van Keken, P.E.McNamara, A.K., Van Keken, P.E., Karoto, S.I.Development of anisotropic structure in the Earth's lower mantle by solid state convection.Nature, No. 6878, March 21, pp. 310-13.MantleGeochemistry, Tectonics
DS2002-1645
2002
Van Keken, P.E.Van Keken, P.E., Hauri, E.H., Ballentine, C.J.Mantle mixing: the generation, preservation and destruction of chemical heterogeneityAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 493-525.mantleGeochemistry
DS2002-1646
2002
Van Keken, P.E.Van Keken, P.E., Hauri, E.H., Ballentine, C.J.Mantle mixing: the generation, preservation and destruction of chemical heterogeneityAnnual Review of Earth and Planetary Sciences, Vol.30,pp. 493-525.mantleGeochemistry
DS2003-0922
2003
Van Keken, P.E.McNamara, A.K., Van Keken, P.E., Karato, S.I.Development of finite strain in the convecting lower mantle and its implications forJournal of Geophysical Research, Vol. 108, 5, ETG3 DOI 10.1029/2002JB001970MantleGeophysics - seismics
DS2003-0923
2003
Van Keken, P.E.McNamara, A.K., Van Keken, P.E., Karato, S.I.Development of finite strain in the convecting lower mantle and its implications forJournal of Geophysical Research, Vol. 108, B5, May 1, 10.1029/2002JB001970.MantleGeophysics - seismics
DS2003-1413
2003
Van Keken, P.E.Van Keken, P.E.The structure and dynamics of the mantle wedgeEarth and Planetary Science Letters, Vol. 215, 3-4, pp. 323-338.MantleSubduction, tectonics
DS200412-1281
2003
Van Keken, P.E.McNamara, A.K., Van Keken, P.E., Karato, S.I.Development of finite strain in the convecting lower mantle and its implications for seismic anisotropy.Journal of Geophysical Research, Vol. 108, B5, May 1, 10.1029/2002 JB001970.MantleGeophysics - seismics
DS200412-2040
2003
Van Keken, P.E.Van Keken, P.E.The structure and dynamics of the mantle wedge.Earth and Planetary Science Letters, Vol. 215, 3-4, pp. 323-338.MantleSubduction, tectonics
DS200512-0639
2005
Van Keken, P.E.Lin, S.C., Van Keken, P.E.Multiple volcanic episodes of flood basalts caused by thermochemical mantle plumes.Nature, No. 7048, July 14, pp. 250-252.MantlePlume, geothermometry
DS200512-0640
2005
Van Keken, P.E.Lin, S-C., Kuo, B-Y., Chiao, L-Y., Van Keken, P.E.Thermal plume models and melt generation in East Africa: a dynamic modeling approach.Earth and Planetary Science Letters, Vol. 237, 1-2, Aug, 30, pp. 175-192.Africa, Tanzania, KenyaCraton, magmatism, mantle convection, geodynamics
DS200512-1121
2005
Van Keken, P.E.Van Keken, P.E., King, S.D.Thermal structure and dynamics of subduction zones: insights from observation and modeling.Physics of the Earth and Planetary Interiors, Vol. 149, 1-2, March 15, pp. 1-6.MantleGeothermometry
DS200612-0820
2006
Van Keken, P.E.Lin, S-C., Van Keken, P.E.Dynamics of thermochemical plumes: 1. plume formation and entrainment of a dense layer.Geochemistry, Geophysics, Geosystems: G3, Vol. 7, Q02006MantleMineral chemistry - bulk. geodynamics, convection
DS200712-0049
2007
Van Keken, P.E.Ballentine, C.J., Brandenburg, J.P., Van Keken, P.E., Holland, G.Seawater recycling into the deep mantle - and the source of 3He.Plates, Plumes, and Paradigms, 1p. abstract p. A56.MantleNoble gases
DS200712-0099
2007
Van Keken, P.E.Brandenburg, J.P., Van Keken, P.E.Deep storage of oceanic crust in a vigourously convecting mantle.Journal of Geophysical Research, Vol. 112, B 6, B06403MantleConvection
DS200712-0100
2007
Van Keken, P.E.Brandenburg, J.P., Van Keken, P.E.Deep storage of oceanic crust in a vigorously convecting mantle.Journal of Geophysical Research, Vol. 112, B6 B06403MantleConvection
DS200712-0338
2007
Van Keken, P.E.Furman, T., Van Keken, P.E., Bryce, J., Lin, S-C.Thermochemical coupling in deep mantle plumes: a case study of Turkana Northern Kenya.Plates, Plumes, and Paradigms, 1p. abstract p. A300.Africa, KenyaAlkaline rocks, picrites
DS200712-0422
2007
Van Keken, P.E.Hauri, E.H., Brandenburg, J.P., Van Keken, P.E.What comes around goes around: mantle convection and the meaning of mantle isochrons.Plates, Plumes, and Paradigms, 1p. abstract p. A385.MantleGeochronology
DS201112-1014
2011
Van Keken, P.E.Styles, E., Goes, S., Van Keken, P.E., Ritsema, J., Smith, H.Synthetic images of dynamically predicted plumes and comparison with a global tomographic model.Earth and Planetary Science Letters, Vol. 311, 3-4, pp. 351-363.MantleTomography
DS201112-1076
2011
Van Keken, P.E.Van Keken, P.E., Hacker, B.R., Syracuse, E.M.,Abers, G.A.Subduction factory: 4. Depth dependent flux of H2O from subducting slabs worldwide.Journal of Geophysical Research, Vol. 116, B01401.MantleSubduction
DS201212-0516
2012
Van Keken, P.E.Nelson, W.R., Furman, T., Van Keken, P.E., Shirey, S.B., Hanan, B.B.Os Hf isotopic insight into mantle plume dynamics beneath the East African Rift system.Chemical Geology, Vol. 320-321 pp. 66-79.Africa, KenyaPicrite
DS201706-1062
2017
van Keken, P.E.Albers, G.A., van Keken, P.E., Hacker, B.R.The cold and relatively dry nature of mantle forearcs in subduction zones.Nature Geoscience, Vol. 10, 5, pp. 333-337.Mantlesubduction

Abstract: Some of Earth's coldest mantle is found in subduction zones at the tip of the mantle wedge that lies between the subducting and overriding plates. This forearc mantle is isolated from the flow of hot material beneath the volcanic arc, and so is inferred to reach temperatures no more than 600 to 800 °C — conditions at which hydrous mantle minerals should be stable. The forearc mantle could therefore constitute a significant reservoir for water if sufficient water is released from the subducting slab into the mantle wedge. Such a reservoir could hydrate the plate interface and has been invoked to aid the genesis of megathrust earthquakes and slow slip events. Our synthesis of results from thermal models that simulate the conditions for subduction zones globally, however, indicates that dehydration of subducting plates is too slow over the life span of a typical subduction zone to hydrate the forearc mantle. Hot subduction zones, where slabs dehydrate rapidly, are an exception. The hottest, most buoyant forearcs are most likely to survive plate collisions and be exhumed to the surface, so probably dominate the metamorphic rock record. Analysis of global seismic data confirms the generally dry nature of mantle forearcs. We conclude that many subduction zones probably liberate insufficient water to hydrate the shallower plate boundary where great earthquakes and slow slip events nucleate. Thus, we suggest that it is solid-state processes and not hydration that leads to weakening of the plate interface in cold subduction zones.
DS201707-1298
2017
van Keken, P.E.Abers, G.A., van Keken, P.E., Hacker, B.R.The cold and relatively dry nature of mantle forearcs in subduction zones.Nature Geoscience, Vol. 10, pp. 333-337.Mantlesubduction

Abstract: Some of Earth's coldest mantle is found in subduction zones at the tip of the mantle wedge that lies between the subducting and overriding plates. This forearc mantle is isolated from the flow of hot material beneath the volcanic arc, and so is inferred to reach temperatures no more than 600 to 800 °C - conditions at which hydrous mantle minerals should be stable. The forearc mantle could therefore constitute a significant reservoir for water if sufficient water is released from the subducting slab into the mantle wedge. Such a reservoir could hydrate the plate interface and has been invoked to aid the genesis of megathrust earthquakes and slow slip events. Our synthesis of results from thermal models that simulate the conditions for subduction zones globally, however, indicates that dehydration of subducting plates is too slow over the life span of a typical subduction zone to hydrate the forearc mantle. Hot subduction zones, where slabs dehydrate rapidly, are an exception. The hottest, most buoyant forearcs are most likely to survive plate collisions and be exhumed to the surface, so probably dominate the metamorphic rock record. Analysis of global seismic data confirms the generally dry nature of mantle forearcs. We conclude that many subduction zones probably liberate insufficient water to hydrate the shallower plate boundary where great earthquakes and slow slip events nucleate. Thus, we suggest that it is solid-state processes and not hydration that leads to weakening of the plate interface in cold subduction zones.
DS201806-1234
2018
van Keken, P.E.Maquire, R., Ritsema, J., Bonnin, M., van Keken, P.E., Goes, S.Evaluating the resolution of deep mantle plumes in teleseismic traveltime tomography.Journal of Geophysical Research, Vol. 123, 1. pp. 384-400.Mantlegeophysics - seismic

Abstract: The strongest evidence to support the classical plume hypothesis comes from seismic imaging of the mantle beneath hot spots. However, imaging results are often ambiguous and it is questionable whether narrow plume tails can be detected by present?day seismological techniques. Here we carry out synthetic tomography experiments based on spectral element method simulations of seismic waves with period T > 10 s propagating through geodynamically derived plume structures. We vary the source?receiver geometry in order to explore the conditions under which lower mantle plume tails may be detected seismically. We determine that wide?aperture (4,000-6,000 km) networks with dense station coverage (<100-200 km station spacing) are necessary to image narrow (<500 km wide) thermal plume tails. We find that if uncertainties on traveltime measurements exceed delay times imparted by plume tails (typically <1 s), the plume tails are concealed in seismic images. Vertically propagating SKS waves enhance plume tail recovery but lack vertical resolution in regions that are not independently constrained by direct S paths. We demonstrate how vertical smearing of an upper mantle low?velocity anomaly can appear as a plume originating in the deep mantle. Our results are useful for interpreting previous plume imaging experiments and guide the design of future experiments.
DS201912-2832
2019
van Keken, P.E.van Keken, P.E., Wada, I., Sime, N., Abers, G.A.Thermal structure of the forearc in subduction zones: a comparison of methodologies.Geochemistry, Geophysics, Geosystems, Vol. 20, pp. 3268-3288.Mantlesubduction

Abstract: Molnar and England (1990, https://doi.org/10.1029/JB095iB04p04833) introduced equations using a semianalytical approach that approximate the thermal structure of the forearc regions in subduction zones. A detailed new comparison with high?resolution finite element models shows that the original equations provide robust predictions and can be improved by a few modifications that follow from the theoretical derivation. The updated approximate equations are shown to be quite accurate for a straight?dipping slab that is warmed by heat flowing from its base and by shear heating at its top. The approximation of radiogenic heating in the crust of the overriding plate is less accurate but the overall effect of this heating mode is small. It is shown that the previous and updated approximate equations become increasingly inaccurate with decreasing thermal parameter and increasing variability of slab dip. It is also shown that the approximate equations cannot be extrapolated accurately past the brittle?ductile transition. Conclusions in a recent paper (Kohn et al., 2018, https://doi.org/10.1073/pnas.1809962115) that modest amount of shear heating can explain the thermal conditions of past subduction from the exhumed metamorphic rock record are invalid due to a number of compounding errors in the application of the Molnar and England (1990, https://doi.org/10.1029/JB095iB04p04833) equations past the brittle?ductile transition. The use of the improved approximate equations is highly recommended provided their limitations are taken into account. For subduction zones with variable dip and/or low thermal parameter finite element modeling is recommended.
DS202005-0733
2020
van Keken, P.E.Geballe, Z.M., Sime, N., Badro, J., van Keken, P.E., Goncharov, A.F.Thermal conductivity near the bottom of the Earth's lower mantle: measurements of pyrolite up to 120 Gpa and 2500 K.Earth and Planetary Science Letters, Vol. 536, 116161, 11p. PdfMantlegeothermometry

Abstract: Knowledge of thermal conductivity of mantle minerals is crucial for understanding heat transport from the Earth's core to mantle. At the pressure-temperature conditions of the Earth's core-mantle boundary, calculations of lattice thermal conductivity based on atomistic models have determined values ranging from 1 to 14 W/m/K for bridgmanite and bridgmanite-rich mineral assemblages. Previous studies have been performed at room temperature up to the pressures of the core-mantle boundary, but correcting these to geotherm temperatures may introduce large errors. Here we present the first measurements of lattice thermal conductivity of mantle minerals up to pressures and temperatures near the base of the mantle, 120 GPa and 2500 K. We use a combination of continuous and pulsed laser heating in a diamond anvil cell to measure the lattice thermal conductivity of pyrolite, the assemblage of minerals expected to make up the lower mantle. We find a value of W/m/K at 80 GPa and 2000 to 2500 K and 5.9 W/m/K at 124 GPa and 2000 to 3000 K. These values rule out the highest calculations of thermal conductivity of the Earth's mid-lower mantle (i.e. W/m/K at 80 GPa), and are consistent with both the high and low calculations of thermal conductivity near the base of the lower mantle.
DS202006-0924
2020
van Keken, P.E.Jones, T.D., Maguire, R.R., van Keken, P.E., Ritsema, J., Koelemeijer, P.Subducted oceanic crust as the origin of seismically slow lower-mantle structures.Progress in Earth and Planetary Science , Vol. 7, 16p. PdfMantlegeophysics - seismics

Abstract: Mantle tomography reveals the existence of two large low-shear-velocity provinces (LLSVPs) at the base of the mantle. We examine here the hypothesis that they are piles of oceanic crust that have steadily accumulated and warmed over billions of years. We use existing global geodynamic models in which dense oceanic crust forms at divergent plate boundaries and subducts at convergent ones. The model suite covers the predicted density range for oceanic crust over lower mantle conditions. To meaningfully compare our geodynamic models to tomographic structures, we convert them into models of seismic wavespeed and explicitly account for the limited resolving power of tomography. Our results demonstrate that long-term recycling of dense oceanic crust naturally leads to the formation of thermochemical piles with seismic characteristics similar to the LLSVPs. The extent to which oceanic crust contributes to the LLSVPs depends upon its density in the lower mantle for which accurate data is lacking. We find that the LLSVPs are not composed solely of oceanic crust. Rather, they are basalt rich at their base (bottom 100-200 km) and grade into peridotite toward their sides and top with the strength of their seismic signature arising from the dominant role of temperature. We conclude that recycling of oceanic crust, if sufficiently dense, has a strong influence on the thermal and chemical evolution of Earth’s mantle.
DS202107-1129
2021
van Keken, P.E.Shirey, S.B., Wagner, L.S., Walter, M.J., Pearson, D.G., van Keken, P.E.Slab transport of fluids to deep focus earthquake depths - thermal modeling constraints and evidence from diamonds.AGU, 10.1029/2020AV000304 28p. PdfMantleinclusions, geothermometry

Abstract: Earthquakes occurring below ?300 km, especially in the mantle transition zone are some of the strongest events experienced on Earth. Deep earthquakes, whose nature and cause are poorly known, occur with regularity and are a deep and prominent result of plate tectonics. We model the paths of subducting slabs to relate pressure-temperature conditions to the experimentally determined mineralogies of the slab crust and mantle. We present a synthesis of mantle minerals included in diamonds derived from same depths as the deep earthquakes to show that fluids exist there. We show that decarbonization/melting reactions in the slab crust and dehydration reactions in the slab mantle can provide fluids to the earthquake generation regions, suggesting that fluids cause or are related to deep earthquakes.
DS200812-1204
2008
Van Kekn, P.E.Van Hunen, J., Van Kekn, P.E., Hynes, A., Davies, G.F.Tectonics of early Earth: some geodynamic considerations.Geological Society of America Special Paper, 440, pp. 157-198.MantleTectonics
DS202004-0514
2020
van Kekn, P.E.Gebralle, Z.M., Sime, N., Badro, J., van Kekn, P.E.Thermal conductivity near the bottom of the Earth's lower mantle: mesurements of pyrolite up to 120 GPa and 2500 K. Earth and Planetary Science Letters, Vol. 536, 116161 7p. PdfMantlegeothermometry

Abstract: Knowledge of thermal conductivity of mantle minerals is crucial for understanding heat transport from the Earth's core to mantle. At the pressure-temperature conditions of the Earth's core-mantle boundary, calculations of lattice thermal conductivity based on atomistic models have determined values ranging from 1 to 14 W/m/K for bridgmanite and bridgmanite-rich mineral assemblages. Previous studies have been performed at room temperature up to the pressures of the core-mantle boundary, but correcting these to geotherm temperatures may introduce large errors. Here we present the first measurements of lattice thermal conductivity of mantle minerals up to pressures and temperatures near the base of the mantle, 120 GPa and 2500 K. We use a combination of continuous and pulsed laser heating in a diamond anvil cell to measure the lattice thermal conductivity of pyrolite, the assemblage of minerals expected to make up the lower mantle. We find a value of W/m/K at 80 GPa and 2000 to 2500 K and 5.9 W/m/K at 124 GPa and 2000 to 3000 K. These values rule out the highest calculations of thermal conductivity of the Earth's mid-lower mantle (i.e. W/m/K at 80 GPa), and are consistent with both the high and low calculations of thermal conductivity near the base of the lower mantle.
DS202008-1462
2020
van Konstantin, V.Zubkova, N.V., Chukanov, N.V., Schafer, C., van Konstantin, V., Pekov,I.V., Pushcharovsky, D. Yu.Al analogue of chayvesite from a lamproite of Cancarix, SE Spain, and its crystal structure.Neues Jahbuch fur Mineralogie, Vol. 196, 3, pp. 193-196.Europe, Spainlamproite

Abstract: Al analogue of chayesite (with Al > Fe3+) was found in a lamproite from Cancarix, SE Spain. The mineral forms green thick-tabular crystals up to 0.4 mm across in cavities. The empirical formula derived from EMP measurements and calculated on the basis of 17 Mg + Fe + Al + Si apfu is (K0.75 Na0.20 Ca0.11)Mg3.04 Fe0.99 Al1.18 Si11.80 O30. The crystal structure was determined from single crystal X-ray diffraction data ( R = 2.38%). The mineral is hexagonal, space group P 6/ mcc, a = 10.09199(12), c = 14.35079(19) Å, V = 1265.78(3) Å3, Z = 2. Fe is predominantly divalent. Al is mainly distributed between the octahedral A site and the tetrahedral T 2 site. The crystal chemical formula derived from the structure refinement is C (K0.73 Na0.16 Ca0.11) B (Na0.02)4 A (Mg0.42 Al0.29 Fe0.29)2 T 2(Mg0.71 Fe0.16 Al0.13)3 T 1(Si0.985 Al0.015)12 O30.
DS1980-0334
1980
Van kooten, G.K.Van kooten, G.K.An Ultrapotassic Basaltic Suite from the Central Sierra Nevada, California: a Study of the Mineralogy, Petrology, Geochemistry and Isotopic Composition.Ph.d. Thesis, University California, Santa Barbara., 100P.United States, California, West CoastBasanite, Whole Rock Geochemistry, Isotope, Geothermometry
DS1950-0194
1954
Van kooten, I.C.Van kooten, I.C.Eerste Onderzoek Op DiamantMeddelingen Van De Geol. Mijnbouwkundige Dienst Van Suriname, No. 11, SEPT. 61P.Suriname, Brazil, Gold Coast, GuyanaBlank
DS200612-1108
2006
Van Koppen, B.Prasad, K.C., Van Koppen, B., Strzepek, K.Equity and productivity in the Olifants River Basin, South Africa.Natural Resources Forum, Vol. 30, 1, Feb pp. 63-75.Africa, South AfricaSocial responsibility
DS200812-0871
2008
Van Kramendonk, M.Pease, V., Percival, J., Smithies, H., Stevens, G., Van Kramendonk, M.When did plate tectonics begin? Evidence from the orogenic record.Geological Society of America Special Paper, 440, pp. 199-228.MantleTectonics
DS201503-0172
2015
Van Kranendonk, J.Roberts, N.M.W., Van Kranendonk, J., Parman, S., Clift, P.D.Continent formation through time.Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 1-16.GlobalGeotectonics
DS201112-0951
2011
Van Kranendonk, M.Shire, S.B., Van Kranendonk, M., Richardson, S.H.SCLM and crustal evidence for 3 GA onset of plate tectonics with implications for the Superior Province.Geological Society of America, Annual Meeting, Minneapolis, Oct. 9-12, abstractCanada, Europe, GreenlandMelting
DS1995-1967
1995
Van Kranendonk, M.J.Van Kranendonk, M.J., Wardle, R.J.Geology of the Archean Nain Province and Paleoproterozoic Torngat OrogenNewfoundland/LabradorGeological Survey of Canada Open File, No. 2927, $ 78.00Labrador, Ungava, QuebecNain Province - Torngat Orogeny, Map -ad
DS1995-1968
1995
Van Kranendonk, M.J.Van Kranendonk, M.J., Wardle, R.J.Geology of the Archean Nain Province and paleoproterozoic Torngat OrogenGeological Survey of Canada (GSC) Open File, No. 2927, 1: 100, 000Quebec, Ungava, Labrador, Northwest territoriesMap, Tectonics - Orogeny
DS1996-1463
1996
Van Kranendonk, M.J.Van Kranendonk, M.J.Tectonic evolution of the Paleoproterozoic Torngat Orogen: evidence from pressure temperature time paths....Tectonics, Vol. 15, No. 4, Aug. pp. 843-69.Quebec, Labrador, UngavaTectonics, Torngat Orogeny
DS1997-1195
1997
Van Kranendonk, M.J.Van Kranendonk, M.J., Wardle, R.J.Crustal scale felxural slip folding during late tectonic amplification of an orogenic boundary....Canadian Journal of Earth Sciences, Vol. 34, pp. 1545-65.Quebec, Labrador, UngavaTectonics, Torngat Orogen
DS200512-1010
2005
Van Kranendonk, M.J.Smithies, R.H., Van Kranendonk, M.J., Champion, D.C.It started with a plume - early Archean basaltic proto-continental crust.Earth and Planetary Science Letters, In Press,AustraliaPilbara, high Ti, geochemistry, SCLM
DS200712-1109
2007
Van Kranendonk, M.J.Van Kranendonk, M.J., Hugh Smithies, R., Hickman, A.H., Champion, D.C.Review: secular tectonic evolution of Archean continental crust: interplay between horizontal and vertical processes in the formation of the Pilbara Craton, Australia.Terra Nova, Vol. 19, 1, Feb. pp. 1-38.AustraliaTectonics
DS200912-0704
2009
Van Kranendonk, M.J.Smithies, R.H., Champion, D.C., Van Kranendonk, M.J.Formation of Paleoarchaen continental crust through infracrustal melting of enriched basalt.Earth and Planetary Science Letters, Vol. 281, 3-4, May 15, pp. 298-306.MantleMelting
DS201112-0953
2011
Van Kranendonk, M.J.Shirey, S.B., Richardson, S.H., Van Kranendonk, M.J.3 Ga onset of the supercontinent cycle: SCLM and crustal evidence.Goldschmidt Conference 2011, abstract p.1863.Europe, GreenlandCraton, subduction
DS201503-0181
2015
Van Kranendonk, M.J.Van Kranendonk, M.J., Smithies, R.H., Griffin, W.L., Huston, D.L., Hickman, A.H., Champion, D.C., Anhaeusser, C.R., Pirajno, F.Making it thick: a volcanic plateau origin of Paleoarchean continental lithosphere of the Pilbara and Kaapvaal cratons.Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 83-111.Australia, Africa, South AfricaGeotectonics
DS1987-0003
1987
Van Landewijk, J.E.J.M.Agyei, E.K., Van Landewijk, J.E.J.M., Armstrong, R.L., Harakal, J.E.Rubidium-strontium and potassium-argon geochronometry of southeasternGhanaJournal of African Earth Science, Vol. 6, No. 2, pp. 153-161GhanaCarbonatite
DS201502-0119
2014
Van Leeuwen, T.Van Leeuwen, T.The enigmatic Sundaland diamonds - a review.Proceedings of Sundaland Resources 2014 MGEI Annual Convention held Nov. 17-18, Palembang, South Sumatra, Indonesia, 28p. Available pdfIndonesia, Kalimantan, MyanmarSundaland diamonds
DS200612-1375
2006
Van Loggerenberg, B.Steward, N.R., Van Loggerenberg, B.The design of a single aggregate concrete on Culli nan diamond mine.Journal of the South African Institute of Mining and Metallurgy, Vol. 106, 3, pp. 213-220.Africa, South AfricaMining
DS200512-1122
2005
Van Lohuizen, K.Van Lohuizen, K.A trail of diamonds.Foreign Policy, Carnegie Endowment for International Peace, Vol. 150, pp. 84-91.AfricaHistory
DS200612-0761
2006
Van lOng, T.Lan, C.Y., Izuka,T., Usuki, T., Wang, K.L., Anh, T.T., Van lOng ,T., O'Reilly, S.Y.Petrology and geochemistry of peridotite xenoliths from Vietnam Indochin a block.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 2. abstract only.ChinaXenolith - geochemistry
DS2001-1186
2001
Van Loon, A.J.Van Loon, A.J.Changing the face of the earthEarth and Planetary Science Letters, Vol. 52, No. 4, Feb. 1, pp. 371-GlobalGeomorphology - brief review
DS2002-1647
2002
Van Loon, A.J.Van Loon, A.J.The complexity of simple geologyEarth Science Reviews, Vol. 59, 1-4, Nov. pp. 287-95.GlobalStructure
DS200812-1205
2008
Van Loon, A.J.Van Loon, A.J.Could snowball Earth have left thick glaciomarine deposits?Gondwana Research, Vol. 14, 1-2, August pp. 73-81.MantleGeomorphology
DS1993-0079
1993
Van Loon, J.C.Barefoot, R.R., Van Loon, J.C., Hall, G.E.M.Analytical methods: field and remote locationsAnalysis of geological materials, editor C. Riddle, pp. 221-261GlobalGeochemistry, Analysis -techniques -general
DS1994-1830
1994
Van Muijen, Ir.H.Van Muijen, Ir.H.Offshore dredge miningSnowden Mining Forum May 18, Perth, 10p. text 10 figuresSouth Africa, NamibiaMarine placers, Dredging
DS1986-0674
1986
Van Niekerk, A.Robinson, D.N., Scott, J.A., Van Niekerk, A., Anderson, V.G.Events reflected in the diamonds of some southern African kimberlitesProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 421-423South AfricaDiamond morphology
DS1989-1285
1989
Van Niekerk, A.Robinson, D.N., Scott, J.A., Van Niekerk, A., Anderson, V.G.The sequence of events reflected in the diamonds of some southern AfricankimberlitesGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 990-1000South AfricaDiamond morphology, Diamond characteristics
DS1990-1522
1990
Van Niekerk, A.Vogel, K.R., Slingerland, R.L., Van Niekerk, A.Factors controlling the location of gold placers in alluvial fans: anumerical studyGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A319GlobalAlluvial, Placers -gold
DS201605-0912
2016
Van Niekerk, L.M.Van Niekerk, L.M., Oliver, A., Armstrong, J., Sikwa, N.A.Pioneering large diamond recovery at Karowe diamond mineDiamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 15-26.Africa, BotswanaDeposit - Karowe
DS1970-0206
1970
Van niekirk, A.A.J.Van niekirk, A.A.J.Optelgoed Diamantsmokkelstories Uit die NoordwesteKaapstad: Reijgeruitgewers, 104P.South AfricaKimberley, Fiction, Diamond Smuggling
DS201709-2069
2016
Van Niekirk, L.M.Van Niekirk, L.M., Olivier, A., Armstrong, J., Sikwa, N.A.Pioneering large diamond recovery at Karowe diamond mine.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 709-714.Africa, Botswanadeposit - Karowe

Abstract: Historically, the recovery of large diamonds in conventional treatment plant flow sheets has been associated with dense media separation (DMS). This is attributed mainly to DMS's highly efficient and proven track record in the concentration and separation of ores with variable solids densities. In most instances, DMS has been utilized as a pre-concentration step ahead of any recovery plant, due to its ability and versatility in reducing feed within a specific size range to manageable volumes for downstream X-ray processing and subsequent diamond recovery. The benefit of using carbon-signature-based detection equipment for retrieving large stones upfront in the flow sheet not only equates to earlier recovery of diamonds from the system, but also lessens the exposure of diamond-bearing ore to additional materials handling, pumping, and/or crushing, which has been known to damage or even break diamonds and decrease revenue.
DS1980-0335
1980
Van noord, C.Van noord, C.Northern Cape TripSth. Afr. Lapidary Journal, Vol. 14, No. 3, PP. 87-89.South AfricaTravelogue, Diamond
DS1990-0838
1990
Van Nostrand, T.King, J.E., Davis, W.J., Relf, C., Van Nostrand, T.Geology of the Contwyoto Lake Nose Lake area, central Slave ProvinceGeological Survey of Canada (GSC) Paper, No. 1990-1C, pp. 177-87.Northwest TerritoriesGeology
DS201804-0701
2018
Van Oman, J.A.Huguet, L., Van Oman, J.A., Hauck, S.A., Willard, M.A.Earth's inner core nucleation paradox.Earth and Planteray Science Letters, Vol. 487, pp. 1-17.MantleCore

Abstract: The conventional view of Earth's inner core is that it began to crystallize at Earth's center when the temperature dropped below the melting point of the iron alloy and has grown steadily since that time as the core continued to cool. However, this model neglects the energy barrier to the formation of the first stable crystal nucleus, which is commonly represented in terms of the critical supercooling required to overcome the barrier. Using constraints from experiments, simulations, and theory, we show that spontaneous crystallization in a homogeneous liquid iron alloy at Earth's core pressures requires a critical supercooling of order 1000 K, which is too large to be a plausible mechanism for the origin of Earth's inner core. We consider mechanisms that can lower the nucleation barrier substantially. Each has caveats, yet the inner core exists: this is the nucleation paradox. Heterogeneous nucleation on a solid metallic substrate tends to have a low energy barrier and offers the most straightforward solution to the paradox, but solid metal would probably have to be delivered from the mantle and such events are unlikely to have been common. A delay in nucleation, whether due to a substantial nucleation energy barrier, or late introduction of a low energy substrate, would lead to an initial phase of rapid inner core growth from a supercooled state. Such rapid growth may lead to distinctive crystallization texturing that might be observable seismically. It would also generate a spike in chemical and thermal buoyancy that could affect the geomagnetic field significantly. Solid metal introduced to Earth's center before it reached saturation could also provide a nucleation substrate, if large enough to escape complete dissolution. Inner core growth, in this case, could begin earlier and start more slowly than standard thermal models predict.
DS200612-0155
2006
Van Orman, J.Bourdon, B., Van Orman, J.236 Ra deficits in OIB: a key to the rate of melt extraction in ther mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.Europe, Cape Verde IslandsMelting
DS201904-0771
2019
Van Orman, J.Reali, R., Jackson, J.M., Van Orman, J., Bower, D.J., Carrez, P., Cordier, P.Modeling viscosity of ( Mg, Fe)O at lowermost mantle conditions.Physics of the Earth and Planetary Interiors, Vol. 287, pp. 65-75.Mantlecore-mantle boundary

Abstract: The viscosity of the lower mantle results from the rheological behavior of its two main constituent minerals, aluminous (Mg,Fe)SiO3 bridgmanite and (Mg,Fe)O ferropericlase. Understanding the transport properties of lower mantle aggregates is of primary importance in geophysics and it is a challenging task, due to the extreme time-varying conditions to which such aggregates are subjected. In particular, viscosity is a crucial transport property that can vary over several orders of magnitude. It thus has a first-order control on the structure and dynamics of the mantle. Here we focus on the creep behavior of (Mg,Fe)O at the bottom of the lower mantle, where the presence of thermo-chemical anomalies such as ultralow-velocity zones (ULVZ) may significantly alter the viscosity contrast characterizing this region. Two different iron concentrations of (Mg1-xFex)O are considered: one mirroring the average composition of ferropericlase throughout most of the lower mantle (x?=?0.20) and another representing a candidate magnesiowüstite component of ULVZs near the base of the mantle (x?=?0.84). The investigated pressure-temperature conditions span from 120?GPa and 2800?K, corresponding to the average geotherm at this depth, to core-mantle boundary conditions of 135?GPa and 3800?K. In this study, dislocation creep of (Mg,Fe)O is investigated by dislocation dynamics (DD) simulations, a modeling tool which considers the collective motion and interactions of dislocations. To model their behavior, a 2.5 dimensional dislocation dynamics approach is employed. Within this method, both glide and climb mechanisms can be taken into account, and the interplay of these features results in a steady-state condition. This allows the retrieval of the creep strain rates at different temperatures, pressures, applied stresses and iron concentrations across the (Mg,Fe)O solid solution, providing information on the viscosity for these materials. A particularly low viscosity is obtained for magnesiowüstite with respect to ferropericlase, the difference being around 10 orders of magnitude. Thus, the final section of this work is devoted to the assessment of the dynamic implications of such a weak phase within ULVZs, in terms of the viscosity contrast with respect to the surrounding lowermost mantle.
DS2001-1187
2001
Van Orman, J.A.Van Orman, J.A., Grove, T.L., Shimizu, N.Rare earth element diffusion in diopside: influence of temperature, pressure and ionic radius and model...Contributions to Mineralogy and Petrology, Vol. 141, pp. 687-703.mantleModel - elastic model for diffusion in silicates
DS2002-1648
2002
Van Orman, J.A.Van Orman, J.A., Grove, T.L., Shimizu, N.Diffusive fractionation of trace elements during production and transport of melt Earth's upper mantleEarth and Planetary Science Letters, Vol.198,1-2,pp.93-112., Vol.198,1-2,pp.93-112.MantleMineralogy - trace elements
DS2002-1649
2002
Van Orman, J.A.Van Orman, J.A., Grove, T.L., Shimizu, N.Diffusive fractionation of trace elements during production and transport of melt Earth's upper mantleEarth and Planetary Science Letters, Vol.198,1-2,pp.93-112., Vol.198,1-2,pp.93-112.MantleMineralogy - trace elements
DS2002-1650
2002
Van Orman, J.A.Van Orman, J.A., Grove, T.L., Shimizu, N., Layne, G.D.Rare earth element diffusion in a natural pyrope single crystal at 2.8 GPaContributions to Mineralogy and Petrology, Vol. 142, No. 4, pp. 416-25.GlobalPetrology - garnet not specific to diamond
DS2003-0734
2003
Van Orman, J.A.Koga, K.T., Van Orman, J.A., Walter, M.J.Diffusive relaxation of carbon and nitrogen isotope heterogeneity in diamond: a newPhysics of the Earth and Planetary Interiors, Vol. 139, 1-2, Sept. 30, pp. 35-43.GlobalPetrology, experimental, geothermometry, zoning
DS2003-1414
2003
Van Orman, J.A.Van Orman, J.A., Fei, Y., Hauri, E.H., Wang, J.Diffusion in MgO at high pressures: constraints on deformation mechanisms andGeophysical Research Letters, Vol. 30, 2, Jan. 15. p. 28.MantleGeochemistry
DS200412-1026
2003
Van Orman, J.A.Koga, K.T., Van Orman, J.A., Walter, M.J.Diffusive relaxation of carbon and nitrogen isotope heterogeneity in diamond: a new thermochronometer.Physics of the Earth and Planetary Interiors, Vol. 139, 1-2, Sept. 30, pp. 35-43.TechnologyPetrology, experimental, geothermometry, zoning
DS200412-2041
2003
Van Orman, J.A.Van Orman, J.A., Fei, Y., Hauri, E.H., Wang, J.Diffusion in MgO at high pressures: constraints on deformation mechanisms and chemical transport at the core mantle boundary.Geophysical Research Letters, Vol. 30, 2, Jan. 15. p. 28.MantleGeochemistry
DS200512-0518
2005
Van Orman, J.A.Keshav, S., Van Orman, J.A.Re Os Pt partitioning in sulfur bearing solid/molten iron metals at 3-22 GPa and 1300-1775 C: is the Earth's outer core so giving?Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, core-mantle boundary
DS200512-1123
2004
Van Orman, J.A.Van Orman, J.A.On the viscosity and creep mechanism of Earth's inner core.Geophysical Research Letters, Vol. 31, 20, Oct. 28, DOI 10.1029/2004 GLO21209MantleMelting
DS200812-0251
2008
Van Orman, J.A.Crispin, K.L., Van Orman, J.A.Diffusion of trivalent cations in MgO: implications for diffusion in Earth's lower mantle.Goldschmidt Conference 2008, Abstract p.A189.MantlePericlase
DS202007-1172
2020
Van Orman, J.A.Prissel, K.B., Krawcznski, M.J., Van Orman, J.A.Fe-Mg and Fe-Mn interdiffusion in ilmenite with implications for geospeedometry using oxides. ( mentions kimberlites)Contributions to Mineralogy and Petrology, Vol. 175, 62 17p. PdfMantleilmenite

Abstract: The Fe-Mg and Fe-Mn interdiffusion coefficients for ilmenite have been determined as a function of temperature and crystallographic orientation. Diffusion annealing experiments were conducted at 1.5 GPa between 800 and 1100 ?C. For Fe-Mg interdiffusion, each diffusion couple consisted of an ilmenite polycrystal and an oriented single crystal of geikielite. The activation energy (Q) and pre-exponential factor (D0) for Fe-Mg diffusion in the ilmenite polycrystal were found to be Q = 188±15 kJ mol?1 and logD0 = ?6.0±0.6 m2 s?1. For the geikielite single crystal, Fe-Mg interdiffusion has Q=220±16 kJ mol?1 and logD0=?4.6±0.7 m2 s?1. Our results indicate that crystallographic orientation did not significantly affect diffusion rates. For Fe-Mn interdiffusion, each diffusion couple consisted of one ilmenite polycrystal and one Mn-bearing ilmenite polycrystal. For Fe-Mn interdiffusion, Q = 264±30 kJ mol?1 and logD0 = ?2.9±1.3 m2 s?1 in the ilmenite. We did not find a significant concentration dependence for the Fe-Mg and Fe-Mn interdiffusion coefficients. In comparing our experimental results for cation diffusion in ilmenite with those previously reported for hematite, we have determined that cation diffusion is faster in ilmenite than in hematite at temperatures <1100 ?C. At oxygen fugacities near the wüstite-magnetite buffer, Fe and Mn diffusion rates are similar for ilmenite and titanomagnetite. We apply these experimentally determined cation diffusion rates to disequilibrium observed in ilmenites from natural volcanic samples to estimate the time between perturbation and eruption for the Bishop Tuff, Fish Canyon Tuff, Mt. Unzen, Mt. St. Helens, and kimberlites. When integrated with natural observations of chemically zoned ilmenite and constraints on pre-eruptive temperature and grain size, our experimentally determined diffusivities for ilmenite can be used to estimate a minimum time between magmatic perturbation and eruption on the timescale of hours to months.
DS202104-0618
2020
Van Orman, J.A.Xu, M., Jing, Z., Bajgain, S.K., Mookherjee, M., Van Orman, J.A., Yu, T., Wang, Y.High pressure elastic properties of dolomite melt supporting carbonate-induced melting in deep upper mantle.Proceedings of the National Academy of Sciences PNAS, Vol. 117, 31, pp. 18285-18291. pdfMantlemelting

Abstract: Deeply subducted carbonates likely cause low-degree melting of the upper mantle and thus play an important role in the deep carbon cycle. However, direct seismic detection of carbonate-induced partial melts in the Earth’s interior is hindered by our poor knowledge on the elastic properties of carbonate melts. Here we report the first experimentally determined sound velocity and density data on dolomite melt up to 5.9 GPa and 2046 K by in-situ ultrasonic and sink-float techniques, respectively, as well as first-principles molecular dynamics simulations of dolomite melt up to 16 GPa and 3000 K. Using our new elasticity data, the calculated VP/VS ratio of the deep upper mantle (?180-330 km) with a small amount of carbonate-rich melt provides a natural explanation for the elevated VP/VS ratio of the upper mantle from global seismic observations, supporting the pervasive presence of a low-degree carbonate-rich partial melt (?0.05%) that is consistent with the volatile-induced or redox-regulated initial melting in the upper mantle as argued by petrologic studies. This carbonate-rich partial melt region implies a global average carbon (C) concentration of 80-140 ppm. by weight in the deep upper mantle source region, consistent with the mantle carbon content determined from geochemical studies.
DS201112-0286
2010
Van Orman, J.A.editors.Dosseto, A., Turner, S.P., Van Orman, J.A.editors.Timescales of magmatic processes: from core to atmosphere.Wiley Blackwell, 272p. $ 99.95MantleBook - geochronology, magmatism
DS1993-1648
1993
Van Overbeke, A.C.Van Overbeke, A.C., Verkaeren, J.neodymium-bearing feldspathic nodules associated with sovite in the Lueshe carbonatite-syenite complex (N-Kivu, Zaire).Terra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 54.Democratic Republic of CongoCarbonatite, Lueshe complex
DS1995-1969
1995
Van Overbeke, A.C.Van Overbeke, A.C.Mineralogy, petrology and geochemistry of metasomatic and hydrothermal processes (fenitization) Lueshe Zaire #1University of Louvain, Ph.d. thesisDemocratic Republic of CongoCarbonatite, Thesis
DS1997-1196
1997
Van Overbeke, A.C.Van Overbeke, A.C., Verkaeren, J., Demaiffe, D.The Luesche alkaline complex: petrogenesis of igneous rocks and geochemical characterization of the metasom..Geological Association of Canada (GAC) Abstracts, Democratic Republic of CongoAlkaline rocks, Metasomatism, fenitisation
DS1995-1970
1995
Van Overbeke, A-C.Van Overbeke, A-C.Mineralogy, petrology and geochemistry of metasomatic and hydrothermalprocesses, fenitization Lueshe...(in French) #2Thesis, University of Louvain-La Neve, Belgique (in French)., Democratic Republic of CongoCarbonatite, Deposit -Lueshe, Kivu area
DS1995-1773
1995
Van Reenan, D.D.Smit, C.A., Van Reenan, D.D.The exhumation of the southern marginal zone of the Limpopo BeltGeological Society of South Africa, Cent. Geocrongress, Guide B2, 48p.South AfricaCrustal processes, Granulite facies metamorphism, Structure, shear zones, faulting
DS2001-1092
2001
Van Reenan, D.D.Smit, C.A., Van Reenan, D.D., Perchuck, L.L.P T conditions of decompression of the Limpopo high grade terrane: record of shear zones.Journal of Metamorphic Geology, Vol. 19, No. 3, pp. 249-68.South Africametamorphism, Limpopo Terrain
DS2002-0556
2002
Van ReenenGerya, T.V., Perchuk, L.L., Maresch, W.V., Willner, A.P., Van ReenenThermal regime and gravitational instability of multi layered continental crust:European Journal of Mineralogy, Vol. 14,4,pp. 687-700.MantleUHP - not specific to diamonds
DS1990-0171
1990
Van Reenen, D.D.Barton, J.M., Van Reenen, D.D., Roering, C.The significance of 3000 Ma granulite facies mafic dikes in the central zone of the Limpopo Belt.Precambrian Research, Vol. 48, pp. 299-308.Southern Africa, ZimbabweDikes, Limpopo Orogeny
DS1992-0093
1992
Van Reenen, D.D.Barton, J.M.Jr., Van Reenen, D.D.When was the Limpopo Orogeny?Precambrian Research, Vol. 55, pp. 7-16South AfricaOrogeny, Limpopo
DS1992-1287
1992
Van Reenen, D.D.Roering, C., Van Reenen, D.D., Smit, C.A., Barton, J.M.Jr., De Beer, J.H.Tectonic model for the evolution of the Limpopo BeltPrecambrian Research, Vol. 55, pp. 539-552South AfricaTectonics, Limpopo Belt
DS1992-1593
1992
Van Reenen, D.D.Van Reenen, D.D., Roering, C., Ashwal, L.D., De Wit, M.J.Regional geological setting of the Limpopo beltPrecambrian Research, Vol. 55, pp. 1-5South AfricaLimpopo Belt, Granulite terrane, craton
DS1993-1649
1993
Van Reenen, D.D.Van Schalkwyk, J.F., De Wit, M.J., Roering, C., Van Reenen, D.D.Tectono-metamorphic evolution of the simatic basement of the Pietersburg greenstone belt relative to the Limpopo Orogeny: evidence from serpentinitePrecambrian Research, Vol. 61, No. 1-2, February pp. 67-88South AfricaTectonics, metamorphism, Greenstone belt
DS1995-1589
1995
Van Reenen, D.D.Roering, C., Van Reenen, D.D., Smit, C.A., Du Toit, R.Deep crustal embrittlement and fluid flow during granulite metamorphism in Limpopo Belt, South AfricaJournal of Geology, Vol. 103, No. 6, pp. 673-686South AfricaTectonics, metamorphism,, Limpopo Belt
DS1995-1971
1995
Van Reenen, D.D.Van Reenen, D.D., McCourt, S., Smit, C.A.Are the Southern and Northern marginal zones of Limpopo belt related to a single continental collisional event. #1South African Journal of Geology, Vol. 98, No. 4, pp. 498-504.South Africa, ZimbabweLimpopo Belt, Kaapvaal craton, Zimbabwe craton
DS1996-1108
1996
Van Reenen, D.D.Perchuk, L.L., Gerya, T.V., Van Reenen, D.D., Safonov, SmitThe Limpopo metamorphic belt, South Africa: decompression and cooling regimes of granulites...Petrology, Vol. 4, No. 6, Nov-Dec. pp. 571-599.South AfricaCraton - Kaapvaal, Limpopo metamorphic belt
DS1996-1464
1996
Van Reenen, D.D.Van Reenen, D.D., McCourt, S., Smit, C.A.Are the southern and northern marginal zones of Limpopo Belt related to a single continental collisional event #2South Africa Journal of Geology, Vol. 95, No. 4, pp. 498-504South AfricaTectonics, Craton, Limpopo Belt
DS1996-1465
1996
Van Reenen, D.D.Van Reenen, D.D., Smit, C.A.The Limpopo metamorphic belt, South Africa: geological setting and relationship of granulite complex....Petrology, Vol. 4, No. 6, Nov-Dec. pp. 562-570.South AfricaCraton - Kaapvaal, Zimbabwe, Limpopo metamorphic belt
DS201707-1356
2016
van Reenen, D.D.Perchuk, A.L., Safonov, O.G., Smit, C.A., van Reenen, D.D., Zkharov, V.S., Gerya, T.V.Precambrian ultra hot orogenic factory: making and reworking of continental crust.Tectonophysics, in press availableMantleUHP

Abstract: Mechanisms of Precambrian orogeny and their contribution to the origin of ultrahigh temperature granulites, granite-greenstone terranes and net crustal growth remain debatable. Here, we use 2D numerical models with 150 °C higher mantle temperatures compared to present day conditions to investigate physical and petrological controls of Precambrian orogeny during forced continental plates convergence. Numerical experiments show that convergence between two relatively thin blocks of continental lithosphere with fertile mantle creates a short-lived cold collisional belt that later becomes absorbed by a long-lived thick and flat ultra-hot accretionary orogen with Moho temperatures of 700–1100 °C. The orogen underlain by hot partially molten depleted asthenospheric mantle spreads with plate tectonic rates towards the incoming lithospheric block. The accretionary orogeny is driven by delamination of incoming lithospheric mantle with attached mafic lower crust and invasion of the hot partially molten asthenospheric wedge under the accreted crust. A very fast convective cell forms atop the subducting slab, in which hot asthenospheric mantle rises against the motion of the slab and transports heat towards the moving orogenic front. Juvenile crustal growth during the orogeny is accompanied by net crustal loss due to the lower crust subduction. Stability of an ultra-hot orogeny is critically dependent on the presence of relatively thin and warm continental lithosphere with thin crust and dense fertile mantle roots subjected to plate convergence. Increased thickness of the continental crust and subcontinental lithospheric mantle, pronounced buoyancy of the lithospheric roots, and decreased mantle and continental Moho temperature favor colder and more collision-like orogenic styles with thick crust, reduced magmatic activity, lowered metamorphic temperatures, and decreased degree of crustal modification. Our numerical modeling results thus indicate that different types of orogens (cold, mixed-hot and ultra-hot) could be created at the same time in the Early Earth, depending on compositional and thermal structures of interacting continental blocks.
DS201901-0055
2018
van Reenen, D.D.Perchuk, A.L., Safonov, O.G., Smit, C.A., van Reenen, D.D., Zakharov, V.S., Gerya, T.V.Precambrian ultra-hot orogenic factory: making and reworking of continental crust.Tectonophysics, Vol. 746, pp. 572-586.Mantlesubduction

Abstract: Mechanisms of Precambrian orogeny and their contribution to the origin of ultrahigh temperature granulites, granite-greenstone terranes and net crustal growth remain debatable. Here, we use 2D numerical models with 150 °C higher mantle temperatures compared to present day conditions to investigate physical and petrological controls of Precambrian orogeny during forced continental plates convergence. Numerical experiments show that convergence between two relatively thin blocks of continental lithosphere with fertile mantle creates a short-lived cold collisional belt that later becomes absorbed by a long-lived thick and flat ultra-hot accretionary orogen with Moho temperatures of 700-1100 °C. The orogen underlain by hot partially molten depleted asthenospheric mantle spreads with plate tectonic rates towards the incoming lithospheric block. The accretionary orogeny is driven by delamination of incoming lithospheric mantle with attached mafic lower crust and invasion of the hot partially molten asthenospheric wedge under the accreted crust. A very fast convective cell forms atop the subducting slab, in which hot asthenospheric mantle rises against the motion of the slab and transports heat towards the moving orogenic front. Juvenile crustal growth during the orogeny is accompanied by net crustal loss due to the lower crust subduction. Stability of an ultra-hot orogeny is critically dependent on the presence of relatively thin and warm continental lithosphere with thin crust and dense fertile mantle roots subjected to plate convergence. Increased thickness of the continental crust and subcontinental lithospheric mantle, pronounced buoyancy of the lithospheric roots, and decreased mantle and continental Moho temperature favor colder and more collision-like orogenic styles with thick crust, reduced magmatic activity, lowered metamorphic temperatures, and decreased degree of crustal modification. Our numerical modeling results thus indicate that different types of orogens (cold, mixed-hot and ultra-hot) could be created at the same time in the Early Earth, depending on compositional and thermal structures of interacting continental blocks.
DS200412-2042
2004
Van Rensburg, L.Van Rensburg, L., Moboeta, M.S., Morgenthal, T.L.Rehabilitation of Co-disposed diamond tailings: growth medium rectification procedures and indigenous grass establishment.Water, Air, and Soil Pollution, Vol. 154, 1-4, May, pp. 101-113. Kluwer Publishing//klTechnologyMining - environmental
DS1982-0614
1982
Van rensburg, W.C.J.Van rensburg, W.C.J.South African Minerals and World DemandInternational Minerals, A National Perspective, Agnew, A.f., Symposium AAAS 90, PP. 97-113.South AfricaDiamonds, Politics, Economics, Ussr
DS1986-0491
1986
Van Riessen, A.Lee, D.C., Van Riessen, A., Terry, K.W.Trace element detection in individual mineral grainsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 475-477GlobalDiamond exploration
DS1989-0870
1989
Van Riessen, A.Lee, D.C., Van Riessen, A., Terry, K.W.Trace elements in mineral grains from kimberlitic and non-kimberlitic sources using X-ray excited XRF in a scanning electron microscope (SEM)Geological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 1146-1153GlobalTrace elements, XRF.
DS1995-0644
1995
Van Roemund, H.L.M.Godard, G., Van Roemund, H.L.M.Deformation induced clinopyroxene fabrics from eclogitesJournal of Structural Geol., Vol. 17, No. 10, pp. 1425-1444.GlobalEclogites, Not specific to diamond exploration
DS200512-0238
2004
Van Roemund, H.L.M.Dobrzhinetskaya, L.F., Green, H.W., Renfro, A.P., Bozhilov, K.N., Spengler, D., Van Roemund, H.L.M.Precipitation of pyroxenes and Mg2SiO4 from majorite garnet: simulation of peridotite exhumation from great depth.Terra Nova, Vol. 16, 6, pp. 325-330.MantlePetrology - peridotite
DS202002-0171
2019
van Roermind, H.Cutts, J.A., Smit, M., Spengler, D., van Roermind, H., Kooijman, E.Punctuated evolution of the Archean SCLM in sync with the supercontinent cycle. Western Gneiss ComplexAmericam Geophysical Union Fall meeting, 1p. AbstractEurope, Norwayeclogites, peridotites

Abstract: The preservation of Archean cratons is typically attributed to the presence of a highly-depleted and buoyant sub-continental lithospheric mantle (SCLM) that is equally old or older than its overlying crust. Time constraints on the formation and petrological evolution of the SCLM are key to investigating its long-term evolution and role in the formation and preservation of the continental crust. Nevertheless, such constraints are difficult to obtain as well-preserved samples of the SCLM are rare and typically lack conventional chronometric minerals. The history of SCLM rocks is typically inferred on the basis of model ages, many of which indicate an Archean origin; however, these dates are difficult to link to specific mineral assemblages or chemical signatures, and the petrological and dynamic processes that these represent. Garnet Lu-Hf geochronology is one of the few chronometers that could overcome this limitation. In this study, a refined method in Lu-Hf garnet chronology was applied to fragments of the Laurentian SCLM that are now exposed as orogenic peridotites in the ultrahigh-pressure domains of the Western Gneiss Complex, Norway. The peridotite bodies comprise a variety of unusually well-preserved rock types-from dunites that record decompression and melting at >350 km depth to fertile lithologies produced by melting and fluid metasomatism. Our internal isochron results from pyrope (after exsolution from majorite) in dunite samples yielded identical Neoarchean ages; these are the first-ever obtained for mantle garnet. The ages coincide with a time interval during which there was voluminous juvenile crust formation, indicating a link between this global process and the deeply sourced mantle upwellings that these samples represent. Internal isochrons from websterite-and clinopyroxenite-hosted pyrope yielded Meso-to Neoproterozoic ages that exactly match two distinct supercontinent break-up events in the overlying continental crust. Together, the new Lu-Hf results indicate that since its extraction during a period of widespread Archean crustal growth, the Laurentian SCLM appears to have largely been at petro-physical and chemical stasis and evolved only during short pulses that ran in sync with the supercontinent cycle.
DS200912-0721
2009
Van RoermundSpengler, D., Brueckner, H.K., Herman, L.M., Van Roermund, Drury, MasonLong lived, cold burial of Baltica to 200 km depth.Earth and Planetary Science Letters, Vol. 281, 1-2, April 30, pp. 27-35.Europe, Baltic ShieldSubduction
DS201112-1160
2011
Van Roermund, H.Zhang, C., Zhang, L., Van Roermund, H., Song, S., Zhang, G.Petrology and SHRIMP U-Pb dating of Xitieshan eclogite, North Quidam, UHP metamorphic belt, NW China.Journal of Asian Earth Sciences, Vol. 32, 4, pp. 752-767.ChinaUHP
DS2001-1188
2001
Van Roermund, H.L.Van Roermund, H.L., Drury, M.R., Barnhoorn, De RondeRelict majoritic garnet microstructures from ultra deep peridotites in western Norway.Journal of Petrology, Vol. 42, No. 1, Jan. pp. 117-58.NorwayPeridotites, Petrology
DS200612-1493
2006
Van Roermund, H.L.Vrijmoed, J.C., Van Roermund, H.L., Davies, G.R.Evidence for diamond grade ultra high pressure metamorphism and fluid interaction in the Svartberget Fe Ti garnet peridotite websterite body, western Gneiss region, Norway.Mineralogy and Petrology, Vol. 88, 1-2, pp. 381-405.Europe, NorwayUHP
DS1988-0179
1988
Van Roermund, H.L.M.Drury, M.R., Van Roermund, H.L.M.Metasomatic origin for iron titanium rich multiphase inclusions in olivine from kimberlite xenolithsGeology, Vol. 16, No. 11, pp. 1035-1088South AfricaMineralogy, Kimberlite xenoliths
DS1989-0371
1989
Van Roermund, H.L.M.Drury, M.R., Van Roermund, H.L.M.Fluid assisted recrystallization in upper mantle peridotite xenoliths fromkimberlitesJournal of Petrology, Vol. 30, No. 1, pp. 133-152South AfricaThaba Putsoa, Xenoliths
DS1992-1192
1992
Van Roermund, H.L.M.Philippot, P., Van Roermund, H.L.M.Deformation processes in eclogitic rocks: evidence for the rheological delamination of the oceanic crust in deeper levels of subduction zones.Journal of Structural Geology, Vol. 14, No. 89, pp. 1059-1077.GlobalEclogites, Crust
DS1995-0645
1995
Van Roermund, H.L.M.Godard, G., Van Roermund, H.L.M.Deformation induced clinopyroxene fabrics from eclogitesJournal of Structural Geology, Vol. 17, No. 10, pp. 1425-1444GlobalTectonics - deformation
DS1999-0764
1999
Van Roermund, H.L.M.Van Roermund, H.L.M., Drury, M.R.Ultra high pressure ( P>6GPa) garnet peridotites in western Norway:exhumation of mantle rocks from 185kM.Terra Nova, Vol. 10, pp. 295-301.NorwayGarnet - majoritic, Mineral chemistry
DS2002-1651
2002
Van Roermund, H.L.M.Van Roermund, H.L.M., Carswell, D.A., Drury, M.R., Heijboer, T.C.Microdiamonds in a megacrystic garnet websterite pod from Bardane on the island ofGeology, Vol. 30, 11, Nov. pp. 959-62.NorwaySubduction - deep continental, diamond genesis
DS200412-0228
2004
Van Roermund, H.L.M.Brueckner, H.K., Van Roermund, H.L.M.Dunk tectonics: a multiple subduction/education model for the evolution of the Scandinavian Caledonides.Tectonics, Vol. 23, 2, 10.1029/2003TC001502Europe, ScandinaviaSubduction
DS200412-0532
2004
Van Roermund, H.L.M.Falus, G., Druru, M.R., Van Roermund, H.L.M., Szabo, C.Magmatism related localized deformation in the mantle: a case study.Contributions to Mineralogy and Petrology, Vol. 146, no. 4, pp. 493-505.MantleMagmatism
DS200512-0142
2005
Van Roermund, H.L.M.Carswell, D.A., Van Roermund, H.L.M.On multiphase mineral inclusions associated with microdiamond formation in mantle derived peridotite lens at Bardane on Fjortoft, west Norway.European Journal of Mineralogy, Vol. 17, 1, pp. 31-42.Europe, NorwayMicrodiamonds
DS200612-0226
2006
Van Roermund, H.L.M.Carswell, D.A., Van Roermund, H.L.M., De Vries, D.F., WiggersScandian ultrahigh pressure metamorphism of Protereozoic basement rocks on Fjortoft and Otroy, western Gneiss region, Norway.International Geology Review, Vol. 48, 11, pp. 957-977.Europe, NorwayUHP
DS200612-1494
2006
Van Roermund, H.L.M.Vrijmoed, J.C., Van Roermund, H.L.M., Davies, G.R.Evidence for diamond grade ultra high pressure metamorphism and fluid interaction in the Svartberget Fe Ti garnet peridotite websterite body, Western GneissMineralogy and Petrology., Vol. 88, 1-2, pp. 381-Europe, NorwayUHP
DS200812-1221
2008
Van Roermund, H.L.M.Vrijmoed, J.C., Smith, D.C., Van Roermund, H.L.M.Raman confirmation of microdiamond in the Svartberget Fe Ti type garnet peridotite, Western Gneiss Region, Western Norway.Terra Nova, Vol. 20, 4, August pp. 295-301.Europe, NorwayMicrodiamonds
DS200812-1222
2008
Van Roermund, H.L.M.Vrijmoed, J.C., Smith, D.C., Van Roermund, H.L.M.Raman confirmation of microdiamond in the Svartberget Fe Ti type garnet peridotite, western Gneiss region, western Norway.Terra Nova, in press availableEurope, NorwayMicrodiamonds
DS200912-0671
2009
Van Roermund, H.L.M.Scamelluri, M., Pettke, T., Van Roermund, H.L.M.Deep subduction fluids and their interaction with the mantle wedge.Goldschmidt Conference 2009, p. A1165 Abstract.MantleSubduction
DS201012-0038
2010
Van Roermund, H.L.M.Barnhoorn, A., Drury, M.R., Van Roermund, H.L.M.Evidence for low viscosity garnet rich layers in the upper mantle.Earth and Planetary Science Letters, Vol. 289, pp. 54-67.MantleRheology, peridotite, UHP
DS201112-0635
2010
Van Roermund, H.L.M.Malaspina, N., Scambelluri, M., Poli, S., Van Roermund, H.L.M., Langenhorst, F.The oxidation state of mantle wedge majoritic garnet websterites metasomatised by C-bearing subduction fluids.Earth and Planetary Science Letters, Vol. 298, 3-4, pp. 417-426.MantleMetasomatism
DS201507-0313
2015
Van Roermund, H.L.M.Gilio, M., Clos, F., Van Roermund, H.L.M.The Frimingen garnet peridotite ( central Swedish Caledonides). A good example of the characteristic PTt path of a cold mantle wedge garnet peridotite.Lithos, Vol. 230, pp. 1-16.Europe, SwedenPeridotite
DS201804-0741
2018
van Roermund, H.L.M.Spengler, D., van Roermund, H.L.M., Drury, M.R.Deep komatiite signature in cratonic mantle pyroxenite… websterite/Rae cratonJournal of Metamorphic Geology, in press availableEurope, Greenland, Norwaymineral chemistry

Abstract: We present new and compiled whole rock modal mineral, major and trace element data from extremely melt depleted but pyroxenite and garnet(?ite) bearing Palaeoarchaean East Greenland cratonic mantle, exposed as three isolated, tectonically strained orogenic peridotite bodies (Ugelvik, Raudhaugene, Midsundvatnet) in western Norway. The studied lithologies comprise besides spinel? and/or garnet?bearing peridotite (dunite, harzburgite, lherzolite) garnet?clinopyroxenite and partially olivine?bearing garnet?orthopyroxenite and ?websterite. Chemical and modal data and spatial relationships between different rock types suggest deformation to have triggered mechanical mixing of garnet?free dunite with garnet?bearing enclosures that formed garnet?peridotite. Inclusions of olivine in porphyroclastic minerals of pyroxenite show a primary origin of olivine in olivine?bearing variants. Major element oxide abundances and ratios of websterite differ to those in rocks expected to form by reaction of peridotite with basaltic melts or silica?rich fluids, but resemble those of Archaean Al?enriched komatiite (AEK) flows from Barberton and Commondale greenstone belts, South Africa. Websterite GdN/YbN, 0.49-0.65 (olivine?free) and 0.73-0.85 (olivine?bearing), overlaps that of two subgroups of AEK, GdN/YbN 0.25-0.55 and 0.77-0.90, with each of them being nearly indistinguishable from one another in rare earth element fractionation but also concentration. Websterite MgO content is high, 22.7-29.0 wt.%, and Zr/Y is very low, 0.1-1.0. The other, non?websteritic pyroxenites overlap - when mechanically mixed together with garnetite - in chemistry with that of AEK. It follows an origin of websterite and likely all pyroxenite that involves melting of a garnet?bearing depleted mantle source. Pyroxene exsolution lamellae in the inferred solidus garnet in all lithological varieties require the pyroxenites to have crystallised in the majorite garnet stability field, at 3-4 GPa (90-120 km depth) at minimum 1600 °C. Consequently, we interpret the websterites to represent the first recognised deep plutonic crystallisation products that formed from komatiite melts. The other pyroxenitic rocks are likely fragments of such crystallisation products. An implication is that a mantle plume environment contributed to the formation of (one of) the worldwide oldest lithospheric mantle underneath the eastern Rae craton.
DS201807-1528
2018
van Roermund, H.L.M.Spengler, D., van Roermund, H.L.M., Drury, M.R.Deep komatiite signature in cratonic mantle pryoxenite.Journal of Metamorphic Geology, Vol. 36, 5, pp. 591-602.Mantlecraton

Abstract: We present new and compiled whole?rock modal mineral, major and trace element data from extremely melt depleted but pyroxenite and garnet(?ite)?bearing Palaeoarchean East Greenland cratonic mantle, exposed as three isolated, tectonically strained orogenic peridotite bodies (Ugelvik, Raudhaugene and Midsundvatnet) in western Norway. The studied lithologies comprise besides spinel? and/or garnet?bearing peridotite (dunite, harzburgite, lherzolite) garnet?clinopyroxenite and partially olivine?bearing garnet?orthopyroxenite and ?websterite. Chemical and modal data and spatial relationships between different rock types suggest deformation to have triggered mechanical mixing of garnet?free dunite with garnet?bearing enclosures that formed garnet?peridotite. Inclusions of olivine in porphyroclastic minerals of pyroxenite show a primary origin of olivine in olivine?bearing variants. Major element oxide abundances and ratios of websterite differ to those in rocks expected to form by reaction of peridotite with basaltic melts or silica?rich fluids, but resemble those of Archean Al?enriched komatiite (AEK) flows from Barberton and Commondale greenstone belts, South Africa. Websterite GdN/YbN, 0.49-0.65 (olivine?free) and 0.73-0.85 (olivine?bearing), overlaps that of two subgroups of AEK, GdN/YbN 0.25-0.55 and 0.77-0.90, with each of them being nearly indistinguishable from one another in not only rare earth element fractionation but also concentration. Websterite MgO content is high, 22.7-29.0 wt%, and Zr/Y is very low, 0.1-1.0. The other, non?websteritic pyroxenites overlap—when mechanically mixed together with garnetite—in chemistry with that of AEK. It follows an origin of websterite and likely all pyroxenite that involves melting of a garnet?bearing depleted mantle source. Pyroxene exsolution lamellae in the inferred solidus garnet in all lithological varieties require the pyroxenites to have crystallized in the majorite garnet stability field, at 3-4 GPa (90-120 km depth) at minimum 1,600°C. Consequently, we interpret the websterites to represent the first recognized deep plutonic crystallization products that formed from komatiite melts. The other pyroxenitic rocks are likely fragments of such crystallization products. An implication is that a mantle plume environment contributed to the formation of (one of) the worldwide oldest lithospheric mantle underneath the eastern Rae craton.
DS201910-2251
2019
van Roermund, H.L.M.Cutts, J.A., Smit, M.A., Spengler, D., Kooijman, E., van Roermund, H.L.M.Two billion years of mantle evolution in sync with global tectonic cycles.Earth and Planetary Science letters, Vol. 528, 115820 11p.Mantlecraton

Abstract: The continental crust and sub-continental lithospheric mantle (SCLM) are co-dependent reservoirs in terms of their geochemistry, tectonics, and long-term evolution. Obtaining insight into the mechanisms of lithosphere formation and differentiation requires robust constraint on the complex petrological history of mantle rocks. This has proven difficult as samples from the deep mantle are rare and, although many may have formed in the Archean, no such age has been obtained directly from mantle-derived silicate minerals. Lutetium-hafnium geochronology of garnet has the potential of overcoming this limitation. In this study, this technique was applied on fragments of the SCLM exposed in the Norwegian Caledonides. The chronologic record of these rocks is rich and extensive, yet it is difficult to interpret and is, in part, inconsistent. Our Lu-Hf results from supersilicic pyrope in dunite provide the first Archean internal isochron ages for mantle rocks. These ages are consistent with a period of juvenile crust formation worldwide and provide a record of deeply sourced mantle upwellings from >350 km depth. Results from fertile rock types indicate that melting and isotope re-equilibration occurred in sync with two Proterozoic supercontinent break-up events that are recorded in the Laurentian and Baltic lithospheres. Together, the results indicate that since its extraction during a period of rapid Archean crustal growth, the SCLM appears to have largely been at petro-physical and chemical stasis, with the exception of major episodes of continental break-up. The evolution of the SCLM is thus, highly punctuated and ultimately controlled by the Wilson cycle.
DS202103-0375
2021
van Roogen, D.Corrigan, D., van Roogen, D., Wodicka, N.Indenter tectonics in the Canadian shield: a case study for Paleoproterozoic lower crust exhumation, orocline development, and lateral extrusion.Precambrian Research, Vol. 355, 106083, 23p. PdfCanada, Quebec, Ungava tectonics

Abstract: There are lingering questions about how far back in geologic time plate tectonic processes began. In the Paleoproterozoic of eastern Laurentia, accretion of intra-oceanic juvenile terranes along the leading edge of the Superior craton apex (Ungava indenter) during the interval 1.87-1.83 Ga was followed by collision with the Churchill plate at ca. 1.83-1.79 Ga. Orthogonal shortening along the indenter led to early obduction of the juvenile terranes including the ca. 2.0 Ga Watts Group ophiolite, followed by out-of-sequence thrusting at ca. 1.83 Ga of granulite-facies crystalline basement of the Sugluk block (Churchill plate) along the Sugluk suture. Exhumation and erosion of the Sugluk block led to deposition of a foreland/delta fan sequence in the Hudson Bay re-entrant (Omarolluk and Loaf formations of the Belcher Group), with detritus sourced exclusively from the Sugluk block. Continued collision led to critical wedge development and orocline formation in the Hudson Bay re-entrant, forming a strongly arcuate fold-thrust belt. On the other (eastern) side of the indenter, material flow during crustal shortening was accommodated by lateral extrusion of microplates towards a then open ocean basin, in a manner similar to present-day extrusion of Indochina as a response to India - South China craton convergence. In the Churchill plate hinterland W-NW of the indenter, propagating strike-slip faults resulted in the far-field extrusion and oblique exhumation of Archean crustal slices of the Rae crustal block. The 1.83-1.79 Ga Superior-Churchill collision accommodated a minimum of 500 km of continent-continent convergence, with resulting style and mechanisms of orogenic growth and material flow similar to those observed in the Alpine-Himalayan orogenic system.
DS200812-1013
2008
Van Rosemund, H.L.M.Scambelluri, M., Petke, T., Van Rosemund, H.L.M.Majoritic garnets monitor deep subsduction fluid flow and mantle dynamics.Geology, Vol. 36, 1, pp.MantleGeodynamics
DS200612-1466
2006
Van Royan, J.Van Royan, J., De Weedt, F., De Gryse, O.HPHT treatment of Type Ia brown diamonds.GIA Gemological Research Conference abstract volume, Held August 26-27, p. 37. 1/2p.TechnologyHPHT
DS200512-0222
2005
Van Royen, J.De Corte, K., Kerremans, Y., Nouwen, B., Van Royen, J.Characterization of carbonado used as a gem.Gemmologie: Zeitschrift der Deutschen Gemmologischen Gesellschaft ** In GERMAN, Vol. 53, 1, pp. 5-22.Diamond - carbonado
DS200712-0225
2006
Van Royen, J.De Corte, K., Anthonis, A., Van Royen, J., Blancaert, M., Barjon, J., Willems, B.Overview of dislocation networks in natural type IIa diamonds.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.122-3. abstract onlyTechnologyDiamond Type IIa
DS201212-0123
2012
Van Royen, J.Chapman, J., De Corte, K., Van Royen, J., Willems, B.FTIR features in Argyle, Diavik and Murowa diamonds.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, ZimbabweDeposit - Murowa
DS202006-0953
2020
Van Rytheoven, A.D.Van Rytheoven, A.D., Schulze, D.J., Davis, D.W.Ultramafic xenoliths from the 1.15 Ga Certac kimberlite, eastern Superior craton.The Canadian Mineralogist, Vol. 56, pp. 267-286. pdfCanada, Quebecdeposit - Certac

Abstract: Xenoliths and xenocrysts of mantle material from kimberlite dikes located underground at the Certac Au mine, Québec, in the eastern Superior Craton, were studied in terms of the major element composition of their constituent minerals. The kimberlite was dated at 1151 ± 46 Ma by the U-Pb perovskite method. This suite thus provides a rare glimpse into the Mesoproterozoic mantle of the Superior Craton. Two parageneses of mantle material unrelated to the kimberlite magmatism occur: (1) an olivine + ilmenite ± magnetite association characterized by relatively Fe-rich olivine (Mg# = 0.68-0.84) and ilmenite enriched in Mg and Cr (4-13 wt.% MgO, Cr2O3 up to 3 wt.%), and (2) spinel peridotite characterized by Mg-rich olivine (Mg# = 0.91-0.94). The Fe-rich association is interpreted as a magmatic cumulate likely unrelated to the kimberlite. No mantle-derived garnet occurs in the xenoliths or as xenocrysts. The presence of Cr-rich spinel (Cr# = 0.84-0.98) in high temperature (860-953 °C) chromite peridotite indicates bulk compositions too depleted in Al for garnet to be stable, although geothermometry suggests they equilibrated at depths corresponding to garnet stability (90-131 km, depending on the geothermal gradient). Alternatively, the presence of phlogopite in two of the three high temperature (i.e., deepest) chromite peridotites suggests the absence of garnet and presence of low-Al chromite may have been caused by metasomatism from a K-rich fluid that replaced garnet with phlogopite + clinopyroxene ± chromite. Less depletion at shallower depths is indicated by a chromite (Cr# = 0.60) dunite that equilibrated at 831 °C and a low temperature (752 °C) Mg-Al-spinel lherzolite.
DS200712-1110
2007
Van Rythoven, A.Van Rythoven, A., Schulze, D.J., Davis, D.W.Upper mantle xenoliths from the Certac kimberlite eastern Superior province.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, Volume 32, 1 pg. abstract p.84.Canada, QuebecGeochronology, mineralogy
DS200912-0786
2009
Van Rythoven, A.Van Rythoven, A., McCandless, T.E., Schulze, D.J.,Bellis, A., Taylor, I.A., Liu, Y.In-situ analysis of diamonds and their mineral inclusions from the Lynx kimberlite dyke complex, central Quebec.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, QuebecDeposit - Lynx
DS200412-2043
2004
Van Rythoven, A.D.Van Rythoven, A.D., Schulze, D.J.Megacrysts and pyroxenites from the Muskox kimberlite, Slave Craton, Nunavut.Geological Association of Canada Abstract Volume, May 12-14, SS14-09 p. 268.abstractCanada, NunavutXenoliths, Jericho
DS200912-0787
2009
Van Rythoven, A.D.Van Rythoven, A.D., Schulze, D.J.In-situ analysis of diamonds and their inclusions from the Diavik mine, Northwest Territories, Canada: mapping diamond growth.Lithos, In press available 44p.Canada, Northwest TerritoriesDeposit - Diavik
DS201112-1077
2011
Van Rythoven, A.D.Van Rythoven, A.D., McCandless, T.E., Schulze, D.J., Bellis, A., Taylor, L.A., Liu, Y.Diamond crystals and their mineral inclusions from the Lynx kimberlite dyke complex, central Quebec.The Canadian Mineralogist, Vol. 49, 3, pp. 691-706.Canada, QuebecDiamond morphology - Lynx dyke
DS201708-1581
2017
Van Rythoven, A.D.Van Rythoven, A.D., Schulze, D.J., Hauri, E.H., Wang, J., Shirey, S.Intra-crystal co-variations of carbon isotopes and nitrogen contents in diamond from three north american cratons. A54 south ( Diavik) Slave craton; Lynx dike Superior craton ; Kelsey Lake Wyoming cratonChemical Geology, in press available 54p.Canada, Northwest Territories, Quebec, United States, Coloradodeposit, A54, Lynx, Kelsey Lake

Abstract: Eighteen diamond samples from the A154 South kimberlite pipe (Diavik Mine), Slave Craton, Northwest Territories (Canada); sixteen diamond samples from the Lynx kimberlite dyke, Superior Craton, Quebec (Canada) and twelve diamond samples from the Kelsey Lake kimberlite pipe, Wyoming Craton, Colorado (USA), were cut through the core-zones, polished, imaged by cathodoluminescence (CL), and analyzed by secondary ion mass spectrometry (SIMS) for carbon isotope composition and nitrogen abundance. Twenty Kelsey Lake diamond plates, including the twelve crystals analyzed by SIMS, were analyzed by Fourier transform infrared spectrometry (FTIR) for nitrogen concentration and aggregation state. Diamond samples from Diavik and Kelsey Lake have average ?13CPDB and nitrogen contents (atomic ppm) similar to those found by earlier studies: averaging between ? 3.9‰ and 486 ppm, and ? 7‰ and 308 ppm, respectively. Samples from the Lynx dyke, investigated for the first time, are substantially different, having ?13C = ?1.2‰ and nitrogen content = 32 ppm (averages). All three localities have examples of significant variations in nitrogen content (> 100 ppm) within single stones. Carbon isotope variation within individual stones is relatively minor (< 2‰). In terms of nitrogen aggregation, samples from the Kelsey Lake kimberlite are dominated by zones of Type IaA, but mixed-type and Type IaB (less common) stones also occur. For the majority of samples, overall intra-diamond zonations of nitrogen abundances and carbon isotope ratios are not in agreement with modeled trends for single-event Rayleigh fractionation of diamond from fluid under nitrogen-compatible conditions at 1100 °C. The involvement of fluids from subducted crustal reservoirs with exceptionally light, and in the case of Lynx samples, exceptionally heavy ?13CPDB values is necessary to explain the observed growth histories of all the samples studied here.
DS202204-0540
2022
Van Rythoven, A.D.Van Rythoven, A.D., Schulze, D.J., Stern, R.A., Lai, M, Y.Composition of diamond from the 95-2 pipe, Lake Timiskaming kimberlite cluster, Superior craton, Canada.The Canadian Mineralogist, Vol. 60, pp. 67-90. pdfCanada, Ontariocathodluminenescence

Abstract: Forty-one samples of diamond from the Jurassic 95-2 kimberlite pipe in the Lake Timiskaming Kimberlite Cluster, Superior Craton, Canada, were imaged using cathodoluminescence and analyzed by secondary ion mass spectrometry and Fourier-transform infrared absorbance spectrometry to determine carbon stable isotope composition, total nitrogen abundance, and nitrogen aggregation state. The carbon isotope compositions results (?13CVPDB) range from -9.11 to -3.57‰, with a mean value of -5.8‰. Intra-stone variation is small (maximum ?2.2‰, and in most individual diamond samples <1‰). Nitrogen contents range from 0.5 to 2040 ppm (mean of 483 ppm). The greatest range of values in a single stone is 825 ppm. The samples are poorly aggregated in terms of nitrogen. The samples are mostly type IaA or IaAB, with a few bordering on type Ib. Diamond growth was episodic, with nitrogen behaving highly compatibly (i.e., D = [N]diamond/[N]fluid >> 1). Precipitation was likely from a carbonate-rich fluid in a peridotitic (lherzolitic) environment within the mantle of the central Superior Craton. This generation of diamond growth is very similar to those reported from the Jurassic age Victor and U2 pipes of the Attawapiskat Kimberlite Cluster, and distinct from a possibly much older (>1.1 Ga) generation of diamond reported in other older host rocks (T1, Wawa, Lynx, and Renard). This older generation of diamond at these other localities is also predominantly of the peridotitic (harzburgitic) paragenesis but contains far less nitrogen (although typically more aggregated as B centers) and has higher ?13CVPDB. The younger generation of diamond formed after mantle heating during formation of the Mid-Continental Rift (ca. 1.1 Ga) destroyed any proximal prior generation(s) of diamond. Igneous activity after 1.1 Ga subsequently refertilized the cratonic mantle to a lherzolitic paragenesis in which the younger generation precipitated.
DS2003-0659
2003
Van Schaack, M.Johansen, T.A., Digranes, P., Van Schaack, M., Lonne, I.Seismic mapping and modeling of near surface sediments in polar areasGeophysics, Vol. 68, 2, pp. 566-73.GlobalGeophysics - seismics - not specific to diamonds
DS200412-0918
2003
Van Schaack, M.Johansen, T.A.,Digranes, P., Van Schaack, M., Lonne, I.Seismic mapping and modeling of near surface sediments in polar areas,Geophysics, Vol. 68, 2, pp. 566-73.TechnologyGeophysics - seismics - not specific to diamonds
DS1995-1800
1995
Van Schahlkwyk, J.Solomon, M.H., Van Schahlkwyk, J.Privitization in the minerals sector in South AfricaRaw Materials Report, Vol. 11, No. 3, pp. 14-24.South AfricaEconomics, legal privitization, Alexcor
DS1993-1649
1993
Van Schalkwyk, J.F.Van Schalkwyk, J.F., De Wit, M.J., Roering, C., Van Reenen, D.D.Tectono-metamorphic evolution of the simatic basement of the Pietersburg greenstone belt relative to the Limpopo Orogeny: evidence from serpentinitePrecambrian Research, Vol. 61, No. 1-2, February pp. 67-88South AfricaTectonics, metamorphism, Greenstone belt
DS200712-0241
2006
Van Schalkwyk, L.Dewey, J.F., Robb, L., Van Schalkwyk, L.Did Bushmanland extensionally unroof Namaqualand?Precambrian Research, Vol. Nov. pp. 173-182.Africa, South AfricaUHT metamorphism
DS201112-1078
2011
Van Schijndel, V.Van Schijndel, V., Cornell, D.H., Hoffman, K.H., Frei, D.Three episodes of crustal development in the Rehoboth Province, Namibia.The Formation and Evolution of Africa: A synopsis of 3.8 Ga of Earth History, Geol. Soc. London Special Publ., 357, pp. 27-47.Africa, NamibiaTectonics
DS1986-0492
1986
Van SchmusLewry, J.F., Collerson, Bickford, Van SchmusAn evolutionary model of the Western Churchill Province and western Margin of the Superior Province and north central United States.Tectonophysics, Vol. 131, pp. 183-97.Saskatchewan, Alberta, MontanaTectonics
DS1992-1594
1992
Van Schmus, W.E.Van Schmus, W.E.Precambrian evolution of the Midcontinent: what to do about Iowa?Geological Society of America (GSA) Abstract Volume, Vol. 24, No. 4, April p. 69. abstract onlyIowaCentral Plains Orogen, Tectonics
DS1975-0462
1977
Van schmus, W.R.Bickford, M.E., Van schmus, W.R.Chronology of Middle and Late Precambrian Crustal Evolution in the Midcontinent Region of North America.Eos, Vol. 59, No. 4, P. 227. (abstract.).GlobalMid-continent
DS1975-1101
1979
Van schmus, W.R.Klasner, J.S., Cannon, W.F., Van schmus, W.R.Lineaments in the Pre Keweenawan Crust and Formation of The keweenawan Rift.Geological Society of America (GSA), Vol. 11, No. 5, P. 233. (abstract.).GlobalMid-continent
DS1981-0084
1981
Van schmus, W.R.Bickford, M.E., Van schmus, W.R.Origin of Middle Proterozoic Granitic and Rhyolitic Rocks In the Mid- Continent Region of North America.Geological Society of America (GSA), Vol. 13, No. 7, P. 410. (abstract.).Wisconsin, Illinois, KansasMid-continent
DS1981-0417
1981
Van schmus, W.R.Van schmus, W.R., Bickford, M.E.Proterozoic Chronology and Evolution of the Midcontinent Region, North America.In: Precambrian Plate Tectonics, PP. 261-296.GlobalMid-continent
DS1982-0336
1982
Van schmus, W.R.Klasner, J.S., Cannon, W.F., Van schmus, W.R.The Pre Keweenawan Tectonic History of Southern Canadian Shield and its Influence on Formation of the Midcontinent Rift.Geological Society of America (GSA) MEMOIR., No. 156, PP. 27-46.GlobalMid-continent
DS1982-0615
1982
Van schmus, W.R.Van schmus, W.R., Bickford, M.E.Delineation of Boundaries Within the Midcontinent Proterozoic Terranes Using Aeromagnetic Mapping.Geological Society of America (GSA), Vol. 14, No. 7, P. 636. (abstract.).GlobalMid-continent
DS1983-0178
1983
Van schmus, W.R.Coates, M.S., Haimson, B.C., Hinze, W.J., Van schmus, W.R.Introduction to the Illinois Deep Hole Project/Journal of Geophysical Research, Vol. 88, No. B9 SEPT. 10, PP. 7267-7750GlobalMid Continent
DS1984-0166
1984
Van schmus, W.R.Bowring, S.A., Van schmus, W.R., Hoffman, P.F.uranium-lead (U-Pb) zircon ages from Athapuscow aulacogen, East Arm of Great Slave @northwest Territories.Canadian Journal of Earth Sciences, Vol. 21, pp. 1315-24.Northwest TerritoriesGeochronology, Alkaline Rocks
DS1984-0355
1984
Van schmus, W.R.Hinze, W.J., Van schmus, W.R.Targeting Deep Scientific Drilling in the MidcontinentGeological Society of America (GSA), Vol. 16, No. 3, P. 146. (abstract.).MichiganMid-continent
DS1985-0691
1985
Van schmus, W.R.Van schmus, W.R., Bickford, M.E.Extension of Early Proterozoic Orogenic Belts Into Midcontinent United States (us)6th. International Conference Basement Tectonics, Held Sante Fe, Septem, P. 38. (abstract.).United States, Central States, Kansas, Iowa, Nebraska, Colorado Plateau, WyomingGeotectonics
DS1985-0692
1985
Van schmus, W.R.Van schmus, W.R., Hinze, W.J.The Mid Continent Rift System (review)Annual Review Earth Science., Vol. 13, PP. 345-383.United StatesMid-continent
DS1986-0074
1986
Van Schmus, W.R.Bickford, M.E., Van Schmus, W.R., Zeitz, I.Proterozoic history of the mid-continent region of North AmericaGeology, Vol. 14, No. 6, June pp. 492-496MidcontinentTectonics
DS1987-0760
1987
Van Schmus, W.R.Van Schmus, W.R., Bickford, M.E., Lewry, J.F.uranium-lead (U-Pb) geochronology in the Trans Hudson Orogen, northern Canada.Canadian Journal of Earth Sciences, Vol. 24, pp. 407-424.SaskatchewanTrans Hudson Orogeny, Geochronology
DS1987-0761
1987
Van Schmus, W.R.Van Schmus, W.R., Bickford, M.E., Lewry, Macdonalduranium-lead (U-Pb) geochronology in the Trans Hudson Orogen, northern SaskatchewanProg. in Phys. Geography, Vol. 24, pp. 407=24.SaskatchewanGeochronology
DS1988-0485
1988
Van Schmus, W.R.Morey, G.B., Van Schmus, W.R.Correlation of Precambrian rocks of the Lake Superiorregion, UnitedStatesUnited States Geological Survey (USGS) Prof. Paper, No. 1241-F, F1-F31, $ 2.00Minnesota, Wisconsin, MichiganArchean basement
DS1988-0747
1988
Van Schmus, W.R.Wallin, E.T., Van Schmus, W.R.Geochronological studies of the Archean Proterozoic transition North central United StatesGeological Society of America Abstracts with Program, Vol. 20, No. 2, January p. 131. Sth. Central, LawrenceIowa, South DakotaMid continent
DS1989-1395
1989
Van Schmus, W.R.Sims, P.K., Van Schmus, W.R., Schulz, K.J., Peterman, Z.E.Tectono-stratigraphic evolution of the early Proterozoic Wisconsin magmatic terranes of the Penokean OrogenCanadian Journal of Earth Sciences, Vol. 26, No. 10, October pp. 2145-2158WisconsinStratigraphy, Orogeny -Penokean
DS1989-1396
1989
Van Schmus, W.R.Sims, P.K., Van Schmus, W.R., Schulz, K.J., Peterman, Z.E.Tectono-stratigraphic evolution of the Early Proterozoic Wisconsin magmatic terranes of the Penokean OrogenCanadian Journal of Earth Sciences, Vol. 26, No. 10, October pp. 2145-2158WisconsinTectonics
DS1990-0201
1990
Van Schmus, W.R.Bickford, M.E., Collerson, K.D., Lewry, J.F., Van Schmus, W.R.Proterozoic collisional tectonism in the Trans-Hudsonorogen, SaskatchewanGeology, Vol. 18, No. 1, January pp. 14-18SaskatchewanProterozoic, Tectonics
DS1990-0202
1990
Van Schmus, W.R.Bickford, M.E., Collerson, K.D., Lewry, J.F., Van Schmus, W.R.Proterozoic collisional tectonism in the Trans-Hudson orogen SaskatchewanGeology, Vol. 18, No. 1, January pp. 14-18SaskatchewanTectonics, Craton, orogeny
DS1990-0345
1990
Van Schmus, W.R.Collerson, K.D., Lewry, J.F., Bickford, M.E., Van Schmus, W.R.Crustal evolution of the buried Precambrian of southern Saskatchewan:implications for diamond explorationModern Exploration Techniques, editors L.S. Beck, C.T. Harper, Saskatchewan, pp. 150-165SaskatchewanGeochronology, Alkaline rocks -potassic suites
DS1990-1498
1990
Van Schmus, W.R.Van Schmus, W.R., Martin, M.W., Sprowl, D.R., Geissman, J.Age, neodymium and lead isotopic composition and magnetic polarity for subsurface samples of the 1100 Ma midcontinent riftGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A174GlobalGeochronology, Geophysics -magnetics
DS1991-1659
1991
Van Schmus, W.R.Stern, R.J., Van Schmus, W.R.Crustal evolution in the Late ProterozoicPrecambrian Research, special issue, Vol. 53, No. 1/2, pp. 1-160Brazil, South America, Nova Scotia, Morocco, SudanCrustal evolution, Paleomagnetism
DS1991-1780
1991
Van Schmus, W.R.Van Schmus, W.R.Age and crustal history of the Midcontinent region in the United StatesEos, Spring Meeting Program And Abstracts, Vol. 72, No. 17, April 23, p. 297MidcontinentGeochronology, Crust
DS1992-1595
1992
Van Schmus, W.R.Van Schmus, W.R.Tectonic setting of the Midcontinent Rift systemTectonophysics, Vol. 213, No. 1-2, special issue, pp. 1-15.MidcontinentTectonics, Rift -overview
DS1992-1596
1992
Van Schmus, W.R.Van Schmus, W.R., Toteu, S.P.Were the Congo Craton and the Sao Francisco joined during the fusion ofGondwanalandEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.365Brazil, Southern AfricaCraton, Supercontinent
DS1992-1681
1992
Van Schmus, W.R.Windom, K.E., Seifert, K.E., Van Schmus, W.R., Wallin, E.T.Archean and Proterozoic rocks from northwestern IowaGeological Society of America (GSA) Abstract Volume, Vol. 24, No. 4, April p. 71. abstract onlyIowaGeneral geology, Precambrian
DS1993-1745
1993
Van Schmus, W.R.Windom, K.E., Van Schmus, W.R., Seifert, K.E., Wallin, E.T., Anderson, R.R.Archean and Proterozoic tectono-magmatic activity along the southern Margin of the Superior Province in northwestern Iowa, United States.Canadian Journal of Earth Sciences, Vol. 30, No. 6, June pp. 1275-1285.IowaTectonics
DS1994-1831
1994
Van Schmus, W.R.Van Schmus, W.R.Identification of lithospheric domains in northeast Brasil and relevance to the ancestry and assembly west Gondwana.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 79-81.BrazilGondwanaland, Geodynamics
DS1996-1466
1996
Van Schmus, W.R.Van Schmus, W.R., Bickford, M.E., Turek, A.Proterozoic geology of the east central midcontinent basementGeological Society of America (GSA) Special Paper, No. 308, pp. 7-32.MidcontinentProterozoic geology
DS1999-0035
1999
Van Schmus, W.R.Babinski, M., Van Schmus, W.R., Chemale, F.lead lead dating and lead isotope geochemistry of Neoproterozoic carbonate rocks-Sao Francisco CratonChemical Geology, Vol. 160, No. 3, Aug. 10, pp. 175-201.BrazilTectonics, metamorphism
DS2000-0334
2000
Van Schmus, W.R.Geraldes, M.C., Van Schmus, W.R., Teixeria, W.Three parallel crystal accretionary arcs (1.79-1.3 Ga) in the southwest Amazon Craton, State of Mato Grosso Brasil.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Mato GrossoGeochronology, Craton - alkaline magmatism
DS2002-0169
2002
Van Schmus, W.R.Bley de Brito Neves, B., Van Schmus, W.R., Fetter, A.Northwestern Africa North eastern Brasil. Major tectonic links and correlation problems.Journal of African Earth Sciences, Vol.34, No.3-4,April-May pp. 275-8.Brazil, AfricaTectonics
DS2002-1354
2002
Van Schmus, W.R.Rohs, C.R., Van Schmus, W.R.Continentl growth along the southern margin of Laurentia during Late Paleoproterozoic and early Meso16th. International Conference On Basement Tectonics '02, Abstracts, 1p., 1p.OklahomaTectonics
DS2003-1079
2003
Van Schmus, W.R.Pinho, M.A., Chemale, F., Van Schmus, W.R., Pinho, F.E.U Pb and Sm Nd evidence for 1.76 - 1.77 Ha magmatism in the Moriru region, MatoPrecambrian Research, Vol. 126, 1-2, pp. 1-25.BrazilCraton - geochronology
DS200412-0394
2004
Van Schmus, W.R.Da Silva Schmitt, R., Trouw, R.A.J., Van Schmus, W.R., Pimentel, M.M.Late amalgamation in the central part of West Gondwana: new geochronological dat a and the characterization of a Cambrian collisiPrecambrian Research, Vol. 133, 1-2, August 5, pp. 29-61.South America, BrazilGeochronology, metamorphism
DS200412-0405
2004
Van Schmus, W.R.Dantas, E.L., Van Schmus, W.R., Hackspacher, P.C., Fetter, A.H., De Brito Neves, B.B., Cordani, U., Nutman, A.The 3.4 3.5 Ga Sao Jose do Campestre Massif, NE Brazil: remnants of the oldest crust in South America.Precambrian Research, Vol. 130, 1-4, April 20, pp. 113-137.South America, BrazilGeochronology, Borborema
DS200412-1549
2003
Van Schmus, W.R.Pinho, M.A., Chemale, F., Van Schmus, W.R., Pinho, F.E.U Pb and Sm Nd evidence for 1.76 - 1.77 Ha magmatism in the Moriru region, Mato Grosso, Brazil: implications for province boundaPrecambrian Research, Vol. 126, 1-2, pp. 1-25.South America, BrazilCraton, geochronology
DS1989-1539
1989
Van Schmus. W.R.Van Schmus. W.R., Bickford, M.E., Anderson, R.R., Shearer, C.K.Quimby, Iowa scientific drill hole: definition of Precambrian crustal features in northwestern IowaGeology, Vol. 17, No. 6, June pp. 536-539IowaMidcontinent, Drilling
DS1997-1197
1997
Van Sickle, J.Van Sickle, J.GPS for land surveyorsEarth Observation Magazine books, $ 55.00GlobalBook - ad, GPS
DS200812-0553
2007
Van Soest, M.C.Kennedy, B.M., Van Soest, M.C.Flow of mantle fluids through the ductile lower crust: Helium isotope trends.Science, Vol. 318 No. 5855 Nov. 30, p. 1433-1436.MantleGeochronology
DS200412-1524
2004
Van Staal, C.Percival, J.A., Bleeker, W., Cook, E.A., Rivers, T., Ross, G., Van Staal, C.PanLithoprobe Workshop IV: intra orogen correlations and comparative orogenic anatomy.Geoscience Canada, Vol. 31, 1, pp. 23-39.Canada, United StatesTectonics, Precambrian, geochronology, orogens
DS1991-1781
1991
Van Staal, C.R.Van Staal, C.R., Fyffe, L.R.Dunnage and Gander zones, New Brunswick: Canadian Appalachian regionNew Brunswick Mineral Resources, Publishing No. GR91-2, 39p. $ 5.00New BrunswickTectonics, Dunnage Zone
DS1994-1832
1994
Van Staal, C.R.Van Staal, C.R.Brunswick subduction complex in the Canadian Appalachians: record of Late Ordovician to SilurianTectonics, Vol. 13, No. 4, August pp. 946-962New BrunswickSubduction complex, Laurentia and Gander margin
DS1999-0498
1999
Van Staal, C.R.Murphy, J.B., Van Staal, C.R., Keppie, J.D.Middle to late Paleozoic Acadian orogeny in the northern Appalachians: a Laramide style plume modifiedGeology, Vol. 27, No. 7, July pp. 653-6.AppalachiaLaramide Orogeny, Tectonics - plume
DS200612-0577
2006
Van Staal, C.R.Hibbard, J.P., Van Staal, C.R., Rankin, D.W., Williams, H.Lithotectonic map of the Appalachian orogen, Canada-United States of America.Geological Survey of Canada, Map 2096A 1: 1,500,000 $ 30.00Canada, United StatesMap - tectonics
DS200912-0867
2009
Van StadenZimmermann, U., Foruie, Naidoo, Van Staden, Chemalle, Nakamura, Koyayashi, Kosler, Beukes, Tait.Unroofing the Kalahari craton: provenance dat a from neoproterozoic to Paleozoic successions.Goldschmidt Conference 2009, p. A1536 Abstract.Africa, South AfricaTectonics
DS1988-0724
1988
Van Stall, C.R.Van Stall, C.R., Williams, P.F.Collision along an irregular margin: a regional plate tectonic interpretation of the Canadian Appalachians: discussionCanadian Journal of Earth Sciences, Vol. 25, No. 11, November pp. 1912-1916AppalachiaTectonics
DS200612-1467
2006
Van Straaten, B.Van Straaten, B., Kopylova, M., Russell, K., Webb, K., Scott Smith, B.Victor North pyroclastic kimberlite, Ontario: resource vs non-resource distinguished.Emplacement Workshop held September, 5p. abstractCanada, OntarioDeposit - Victor, geology, mineral compositions
DS200612-1468
2006
Van Straaten, B.Van Straaten, B., Kopylova, M., Russell, K., Webb, K., Scott Smith, B.Victor Northwest kimberlite pipe, Ontario: alternating volcaniclastic and apparent coherent extrusive rocks.Emplacement Workshop held September, 5p. abstractCanada, OntarioDeposit - Victor, pipe morphology, lithologies
DS200812-1206
2008
Van Straaten, B.I.Van Straaten, B.I., Kopylova, M.G., Russell, J.K., Webb, K.J., Scott Smith, B.H.Discrimination of a diamond resource and non-resource domains in the Victor North pyroclastic kimberlite, Canada.Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 128-138.Canada, Ontario, AttawapiskatPetrography, fugacity, spinel group
DS201112-1079
2011
Van Straaten, B.I.Van Straaten, B.I.,Kopylova, M.G., Russeell, J.K., Scott Smith, B.H.A rare occurrence of a crater filling clastogenic extrusive coherent kimberlite, Victor Northwest, ( Ontario, Canada).Bulletin Volcanology, In press available, 18p.Canada, Ontario, AttawapiskatGeology - Victor Northwest
DS200912-0788
2009
Van Straaten, B.J.Van Straaten, B.J., Kopylova, M.G., Russell, J.K., Webb, K.J., Scott Smith, B.H.Stratigraphy of the intra crater volcaniclastic deposits of the Victor northwest kimberlite, northern Ontario, Canada.Lithos, In press - available 30p.Canada, Ontario, AttawapiskatDeposit - Victor
DS1985-0072
1985
Van straaten, J.Boppart, H., Van straaten, J., Silvera, I.F.Raman Spectra of Diamond at High PressuresPhysical Review B: Condensed Matter., Vol. 32, No. 2, JULY 15TH. PP. 1423-1425.GlobalBlank
DS1986-0828
1986
Van Straaten, P.Van Straaten, P.Some aspects of the geology of carbonatites in southwest TanzaniaGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 140. (abstract.)Tanzania, East AfricaCarbonatite
DS1989-1540
1989
Van Straaten, P.Van Straaten, P.Nature and structural relationships of carbonatites from southwest and west TanzaniaCarbonatites -Genesis and Evolution, Ed. K. Bell Unwin Hyman Publ, pp. 177-199TanzaniaCarbonatite
DS1960-0220
1962
Van straten, O.J.Boocock, C., Van straten, O.J.Notes on the Geology and the Hydrogeology of the Central Kalahari Region, Bechuana land Protectorate.Geological Society of South Africa Transactions, Vol. 65, PP. 125-171.BotswanaGeology
DS201112-1080
2010
Van Stratten, B.Van Stratten, B.The eruption of kimberlite: insights from the Victor North kimberlite pipes, northern Ontario.University of British Columbia, Phd Thesis, 193p.Canada, Ontario, James bay Lowlands, AttawapiskatThesis - note availability based on request via author
DS200912-0789
2009
Van Stratten, B.I.Van Stratten, B.I., Kopylova, M.B., Russell, J.K., Scott Smith, B.H.Welded kimberlite?GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, OntarioDeposit - Victor
DS201605-0852
2016
Van Strijp, T.Judeel, G., Swaneoel, T., Holder, A., Swarts, B., Van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine No. 1 shaft underneath the existing operating shaft.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 301-316.Africa, South AfricaDeposit - Cullinan
DS201605-0910
2016
Van Strijp, T.Tukker, H., Holder, A., Swarts, B., Van Strijp, T., Grober, E.The CCUT black cave design for the Culli nan diamond mine.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 57-70.Africa, South AfricaDeposit - Cullinan
DS201605-0911
2016
Van Strijp, T.Tukker, H., Marsden, H., Holder, A., Swarts, B., Van Strijp, T., Grobler, E., Engelbrecht, F.Koffiefontein diamond mine sublevel cave design.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 129-142.Africa, South AfricaDeposit - Koffiefontein
DS201605-0913
2016
Van Strijp, T.Van Strijp, T., Boshoff, P., du Toit, R.How the mining design evolved through stress and deformation modelling at Finsch diamond mine.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 251-262.Africa, South AfricaDeposit - Finsch
DS201612-2308
2016
van Strijp, T.Judeel, G., Swanepoel, T., Holder, A., Swarts, B., van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine no. 1 shaft underneath the existing operating shaft, with emphasis on rock engineering considerations.Journal of South African Institute of Mining and Metallurgy, Vol. 116, Aug. pp. 745-753.Africa, South AfricaDeposit - Cullinan

Abstract: In 2012, Cullinan Diamond Mine began an expansion programme with the shaft deepening and development of access to the C-Cut 1 block at approximately 839 m below surface. The expansion programme is funded by a combination of bank loans and retained operating profit generated by the mine. Continuous production during deepening of the No. 1 Shaft, which is the rock hoisting shaft, was therefore critical for sustainability and efficiency as well as overall funding of the project. The deepening method, support design and verification, as well as learning outcomes pertaining to the extension of the No. 1 Shaft underneath the existing operating shaft are summarized, with emphasis on the importance of gaining some understanding of the shaft's host rock mass.
DS201709-2007
2016
van Strijp, T.Judeel, G., Swanepoel, T., Holder, A., Swarts, B., van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine No. 1 shaft underneath the existing operating shaft, with emphasis on rock engineering considerations.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 745-752.Africa, South Africadeposit - Cullinan

Abstract: In 2012, Cullinan Diamond Mine began an expansion programme with the shaft deepening and development of access to the C-Cut 1 block at approximately 839 m below surface. The expansion programme is funded by a combination of bank loans and retained operating profit generated by the mine. Continuous production during deepening of the No. 1 Shaft, which is the rock hoisting shaft, was therefore critical for sustainability and efficiency as well as overall funding of the project. The deepening method, support design and verification, as well as learning outcomes pertaining to the extension of the No. 1 Shaft underneath the existing operating shaft are summarized, with emphasis on the importance of gaining some understanding of the shaft's host rock mass.
DS201709-2066
2016
van Strijp, T.Tukker, H., Holder, A., Swarts, B., van Strijp, T., Grobler, E.The CCUT block cave design for Culli nan diamond mine.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 715-723.Africa, South Africadeposit - Cullinan
DS200912-0790
2009
Van Summeren, J.R.Van Summeren, J.R., Vandenberg, A.P., Van der Hilst, R.D.Upwellings from a deep mantle reservoir filtered at the 660 km phase transition in thermochemical convection models and implications for intra-plate volcanism.Physics of the Earth and Planetary Interiors, Vol. 172, 3-4, pp. 210-224.MantleGeothermometry
DS1990-1499
1990
Van Tendeloo, G.Van Tendeloo, G., Luyten, W., Woods, G.S.Voidites in pure type 1AB diamondsPhilosophical Magazine Letters, Vol. 61, No. 6, June pp. 343-348GlobalExperimental mineralogy, Diamond morphology -Type IAB.
DS200612-1469
2005
Van Thielen, P.Van Thielen, P., VanSummeren, J., VanderHilst, R.D., VandenBerg, A.P., Vlaar, N.J.Numerical study of the origin and stability of chemically distinct reservoirs deep in the Earth's mantle.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 117-136.MantleGeochemistry
DS200512-1124
2004
Van Thiemen, P.Van Thiemen, P., Van den Berg, A.P., Vlaar, N.J.On the formation of continental silicic melts in thermochemical mantle convection models: implications for early Earth.Tectonophysics, Vol. 394, 1-2, pp. 111-138.MantleGeothermometry
DS2001-0651
2001
Van ToanLan, C.Y., Chung, S.L., Lo, Lee, Wang, Li, Van ToanFirst evidence for Archean continental crust in northern Vietnam and its implications for crustal ...Geology, Vol. 29, No. 3, Mar. pp.219-22.GlobalTectonic evolution, Geochronology, Yangtze Craton
DS201605-0859
2016
Van Tongeren, J.A.Levin, V., Van Tongeren, J.A., Servali, A.How sharp is the sharp Archean Moho? Example from eastern Superior Province.Geophysical Research Letters, Vol. 43, 5, pp. 1928-1933.Canada, OntarioGeophysics - seismics

Abstract: The Superior Province of North America has not experienced major internal deformation for nearly 2.8?Gyr, preserving the Archean crust in its likely original state. We present seismological evidence for a sharp (less than 1?km) crust-mantle boundary beneath three distinct Archean terranes and for a more vertically extensive boundary at sites likely affected by the 1.2-0.9?Ga Grenville orogeny. At all sites crustal thickness is smaller than expected for the primary crust produced by melting under higher mantle potential temperature conditions of Archean time. Reduced thickness and an abrupt contrast in seismic properties at the base of the undisturbed Archean crust are consistent with density sorting and loss of the residues through gravitational instability facilitated by higher temperatures in the upper mantle at the time of formation. Similar sharpness of crust-mantle boundary in disparate Archean terranes suggests that it is a universal feature of the Archean crustal evolution.
DS201811-2565
2018
Van Tongeren, J.A.Dasgupta, R., Van Tongeren, J.A., Watson, E.B., Ghiorso, M.Volatile bearing partial melts beneath oceans and continents; where, how much, and of what composition.American Journal of Science, Vol. 318, 1, pp. 141-165.Mantlemelting

Abstract: Besides depth and temperature, CO2 and H2O, are the two most important variables in stabilizing partial melts in the Earth's mantle. However, despite decades of experimental studies on the roles of these two volatile species in affecting mantle melting, ambiguity remains in terms of the stability, composition, and proportion of volatile-bearing partial melts at depths. Furthermore, the difference in the influence of H2O versus CO2 in production of mantle melts is often inadequately discussed. Here I first discuss how as a function of depth and concentration of volatiles, the peridotite + H2O versus peridotite + CO2 near-solidus melting conditions differ - discussing specifically the concepts of saturation of volatile-bearing phases and how the mode of storage of ‘water’ and carbon affects the near solidus melting relations. This analysis shows that for the Earth's mantle beneath oceans and continents, deep, volatile-induced melting is influenced mostly by carbon, with water-bearing carbonated silicate melt being the key agent. A quantitative framework that uses the existing experimental data, allows calculation of the loci, extent of melting, and major element compositions of volatile-bearing partial melts beneath oceans and continents. How the domains of volatile-bearing melt stability are affected when possible oxygen fugacity variation at depths in the mantle is taken into account is also discussed. I show that trace amount hydrous carbonated silicate melt is likely stabilized at two or more distinct depths in the continental lithospheric mantle, at depths ranges similar to where mid-lithospheric discontinuity (MLD) and lithosphere-asthenosphere boundary (LAB) have been estimated from seismology. Whereas beneath oceans, hydrous carbonated silicate melt likely remain continuously stable from the base of the thermal boundary layer to at least 200 km or deeper depending on the prevailing oxygen fugacity at depths. Hotter mantles, such as those beneath oceans, prevent sampling strongly silica-undersaturated, carbonated melts such as kimberlites as shallower basaltic melt generation dominates. Thick thermal boundary layers, such as those in cratonic regions, on the other hand allow production of kimberlitic to carbonatitic melt only. Therefore, the increasing frequency of occurrence of kimberlites starting at the Proterozoic may be causally linked to cooling and growth of sub-continental mantles through time.
DS201312-0001
2013
Van Tongeron, J.A.Abbott, D.H., Mooney, W.D., Van Tongeron, J.A.The character of the Moho and lower crust within Archean cratons and the tectonic implications.Tectonophysics, Vol. 609, pp. 690-705.Africa, South Africa, ZimbabweKaapvaal Craton
DS1998-0146
1998
Van Vliet-Lanoe, B.Bourgeois, O., Dauteruil, O., Van Vliet-Lanoe, B.Pleistocene subglacial volcanism in Iceland: tectonic implicationsEarth and Planetary Science Letters, Vol. 164, No.1-2, Dec.15, pp. 165-78.GlobalGeomorphology, Tectonics
DS1975-1250
1979
Van vuuren, C.Van vuuren, C., Cole, D., Stettler, E.The Lichtenburg Diamond Bearing Gravels. Some ObservationsGeological Survey of South Africa, UNPUBL. ReportSouth AfricaGeology
DS1996-0694
1996
Van Vuuren, C.J.Johnson, M.R., Van Vuuren, C.J., Shoko, U.Stratigraphy of the Karoo Supergroup in southern Africa: an overviewJournal of African Earth Sciences, Vol. 23, No. 1, pp. 3-16.South AfricaStratigraphy, Karoo Supergroup
DS1999-0411
1999
Van Wagoner, N.Leybourne, M.I., Van Wagoner, N., Ayres, L.D.Partial melting of a refractory subducted slab in a Paleoproterozoic islandarc: implications global cyclesGeology, Vol. 27, No. 8, Aug. pp. 731-34.MantleMagma - melting, geochemical, global cycles, Subduction
DS1998-1640
1998
Van Wees, J.D.Ziegler, P.A., Van Wees, J.D.Mechanical controls on collision related compressional intraplatedeformation.Tectonophysics, Vol. 300, No. 1-4, Dec. 31, pp. 103-30.MantleTectonics, Deformation, geodynamics
DS200512-0172
2005
Van Wees, J.D.Cloetingh, S., Van Wees, J.D.Strength reversal in Europe's intraplate lithosphere: transition from basin inversion to lithospheric folding.Geology, Vol. 33, 4, Apr. pp. 285-288.EuropeTectonics
DS2000-0972
2000
Van Westeren, W.Van Westeren, W., Blundy, J.D., Wood, B.J.Effect of Fe2 on garnet melt trace element partioning: experiments in FCMAS crystal chemical controls naturalLithos, Vol. 53, No. 3-4, Sept. pp. 189-201.GlobalPetrology - experimental, Mineralogy - garnet
DS200912-0299
2009
Van Westeren, W.Hin, R.C., Morel, M.L.A., Nebel, O., Mason, P.R.D., Van Westeren, W., Davies, G.R.Formation and temporal evolution of the Kalahari sub-cratonic lithospheric mantle: constraints from Venetia xenoliths, South Africa.Lithos, In press - available 30p.Africa, South AfricaDeposit - Venetia
DS1998-1518
1998
Van Westerenen, W.Van Westerenen, W., Blundy, Purton, WoodTowards a predictive model for garnet melt trace element partitioning:experimental and computational..Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1580-1.MantleGeochemistry, Garnets, grossular
DS200712-0220
2007
Van WestrenenDavies, G.R., Wasch, L., Van der Zwan, F., Morel, M.L.A., Nebel, Van Westrenen, Pearson, HellebrandThe origin of silica rich Kaapvaal lithospheric mantle.Plates, Plumes, and Paradigms, 1p. abstract p. A205.Africa, South AfricaDeposit - Kimberley
DS2001-1189
2001
Van Westrenen, W.Van Westrenen, W., Wood, B.J., Blundy, J.D.A predictive thermodynamic model of garnet melt trace element partitioningContributions to Mineralogy and Petrology, Vol. 142, No. 2, Nov. pp. 219-234.GlobalGarnet - mineralogy
DS200412-0834
2004
Van Westrenen, W.Hirose, K., Shimizu, N., Van Westrenen, W., Fei, Y.Trace element partitioning in the Earth's lower mantle and implications for geochemical consequences of partial melting at the cPhysics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 249-260.MantleGeochemistry
DS200712-0409
2007
van Westrenen, W.Hanchar, J.M., van Westrenen, W.Rare earth element behaviour in zircon melt systems.Elements, Vol. 3, 1, Feb. pp.37-42.MantleMelting
DS200812-0272
2008
Van Westrenen, W.De Meijer, R.J., Van Westrenen, W.The feasibility and implications of nuclear georeactors in Earth's core-mantle boundary region.South African Journal of Science, Vol. 104, 3/4, pp. 111-118.MantleBoundary
DS201112-0909
2011
Van Westrenen, W.Sanloup, C., Van Westrenen, W., Dasgupta, R., Maynard-Casely, H., Perrillat, J-P.Compressability change in iron-rich melt and implications for core formation models.Earth and Planetary Science Letters, Vol. 306, 1-2, pp. 118-122.MantleMelting
DS202202-0205
2022
van Westrenen, W.Lin, Y., van Westrenen, W., Mao, H-K.Oxygen controls on magmatism rocky exoplanets. Proceedings of the National Academy of Sciences, Vol. 78, 10.1073/pnas2110427118 6p. PdfCosmosmelting

Abstract: Refractory oxygen bound to cations is a key component of the interior of rocky exoplanets. Its abundance controls planetary properties including metallic core fraction, core composition, and mantle and crust mineralogy. Interior oxygen abundance, quantified with the oxygen fugacity (fO2), also determines the speciation of volatile species during planetary outgassing, affecting the composition of the atmosphere. Although melting drives planetary differentiation into core, mantle, crust, and atmosphere, the effect of fO2 on rock melting has not been studied directly to date, with prior efforts focusing on fO2-induced changes in the valence ratio of transition metals (particularly iron) in minerals and magma. Here, melting experiments were performed using a synthetic iron-free basalt at oxygen levels representing reducing (log fO2 = ?11.5 and ?7) and oxidizing (log fO2 = ?0.7) interior conditions observed in our solar system. Results show that the liquidus of iron-free basalt at a pressure of 1 atm is lowered by 105 ± 10?°C over an 11 log fO2 units increase in oxygen abundance. This effect is comparable in size to the well-known enhanced melting of rocks by the addition of H2O or CO2. This implies that refractory oxygen abundance can directly control exoplanetary differentiation dynamics by affecting the conditions under which magmatism occurs, even in the absence of iron or volatiles. Exoplanets with a high refractory oxygen abundance exhibit more extensive and longer duration magmatic activity, leading to more efficient and more massive volcanic outgassing of more oxidized gas species than comparable exoplanets with a lower rock fO2.
DS200712-0203
2007
Van Wijk, J.Corti, G., Van Wijk, J., Cloetingh, S., Morley, C.K.Tectonic inheritance and continental rift architecture: numerical and analogue models of the East African Rift system.Tectonics, Vol. 26, TC6006AfricaTectonics
DS201511-1829
2015
Van Wijk, J.Coblentz, D., Van Wijk, J., Richardson, R.M., Sandiford, M.The upper mantle geoid: implications for continental structure and the intraplate stress field.Geological Society of America Special Paper, No. 514, pp. SPE514-13.MantleGeophysics - seismics

Abstract: We use the fact that geoid anomalies are directly related to the local dipole moment of the density-depth distribution to help constrain density variations within the lithosphere and the associated tectonic stresses. The main challenge with this approach is isolating the upper mantle geoid contribution from the full geoid (which is dominated by sources in the lower mantle). We address this issue by using a high-pass spherical harmonic filtering of the EGM2008-WGS84 geoid to produce an "upper mantle" geoid. The tectonic implications of the upper mantle are discussed in terms of plate tectonics and intraplate stresses. We find that globally there is about a 9 meter geoid step associated with the cooling oceanic lithosphere that imparts a net force of ~2.5x1012 N/m in the form of "ridge push" - a magnitude that is consistent with 1-d models based on first-order density profiles. Furthermore, we ind a consistent 6 meter geoid step across passive a continental margin which has the net effect of educing the compressive stresses in the continents due to the ridge force. Furthermore, we use the pper mantle geoid to reevaluate the tectonic reference state which previously studies estimated using n assumption of Airy-based isostasy. Our evaluation of the upper mantle geoid confirms the near quivalence of the gravitational potential energy of continental lithosphere with an elevation of about 750 meters and the mid-ocean ridges. This result substantiates early conclusions about the tectonic reference state and further supports the prediction that continental regions are expected to be in a slightly extensional state of stress.
DS201611-2102
2016
van Wijk, J.Currie, C.A., van Wijk, J.How craton margins are preserved: insights from geodynamic models.Journal of Geodynamics, Vol. 100, pp. 144-158.MantleConvection

Abstract: Lateral variations in lithosphere thickness are observed in many continental regions, especially at the boundary between the ancient cratonic core and the adjacent more juvenile lithosphere. In some places, such as the North America craton margin in western Canada and the Sorgenfrei-Tornquist Zone in northern Europe, the transition in lithosphere thickness has a steep gradient (>45°) and it appears to be a long-lived feature (at least 50 Ma). We use thermal-mechanical numerical models to address the dynamics of lithospheric thickness changes on timescales of 100 Ma. Models start with the juxtaposition of 60 km thick lithosphere ("mobile belt") and 160 km thick lithosphere ("craton"). In the reference model, all mantle materials have a damp olivine rheology and a density comparable to primitive mantle. With this configuration, edge-driven mantle convection occurs at the craton boundary, resulting in a lateral smoothing of the thickness transition. The density and rheology of the craton mantle lithosphere are then varied to approximate changes in composition and water content. For all densities, a steep transition is maintained only if the craton strength is 5-50 times stronger than the reference damp olivine. If dry olivine is an upper limit on strength, only cratonic mantle with moderate compositional buoyancy (20-40 kg/m3 less dense than primitive mantle) remains stable. At higher densities, the thick lithosphere is eroded through downwellings, and the craton margin migrates inboard. Conversely, a compositionally buoyant craton destabilises through lateral spreading below the mobile belt.
DS2001-1190
2001
Van Wijk, J.W.Van Wijk, J.W., Givers, R., Furlong, K.P.Three dimensional thermal modeling of the California upper mantle: a slab window vs. stalled slab.Earth and Planetary Science Letters, Vol. 186, No. 2, March 30, pp. 175-86.CaliforniaSubduction, Geothermometry
DS2001-1191
2001
Van Wijk, J.W.Van Wijk, J.W., Huismans, R.S., Voorde, M., CloetinghMelt generation at volcanic continental margins: no need for a mantle plume?Geophysical Research Letters, Vol. 28, No. 20, Oct. 15, pp. 3995-8.MantleTectonics, Melting
DS201012-0812
2010
Van Wijk, J.W.Van Wijk, J.W., Baldridge, W.S., Van Hunen, J., Goes, S., Aster, R., Coblentz, D.D., Grand, S.P., Ni, J.Small scale convection at the edge of the Colorado Plateau: implications for topography, magmatism, and evolution of Proterozoic lithosphere.Geology, Vol. 38, 7, pp. 611-614.United States, Colorado PlateauMagmatism
DS200512-1125
2005
Van Wilk, J.Van Wilk, J.Formation of volcanic rifted margins: influence of the pre-Rift lithosphere architecture.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantle, AfricaMantle plume, rifting
DS201512-1981
2015
Van Wychen, W.Van Wychen, W., Copland, L., Burgess, D.O., Gray, L., Schaffer, N., Fisher, T.Glacier velocities and dynamic discharge from the ice masses of Baffin Island and Bylot Island, Nunavut, Canada.Canadian Journal of Earth Sciences, Vol. 52, 11, pp. 980-989.Canada, Nunavut, Baffin IslandGeomorphology

Abstract: Speckle tracking of ALOS PALSAR fine beam data from 2007-2011 are used to determine the surface motion of major ice masses on Baffin Island and Bylot Island in the southern Canadian Arctic Archipelago. Glacier velocities are low overall, with peaks of ?100 m a?1 and means of ?20-60 m a?1 common along the main trunk of many outlet glaciers. Peak velocities on Penny and Bylot Island ice caps tend to occur near the mid-sections of their primary outlet glaciers, while the fastest velocities on all other glaciers usually occur near their termini due to relatively large accumulation areas draining through narrow outlets. Estimates of ice thickness at the fronts of tidewater-terminating glaciers are combined with the velocity measurements to determine a regional dynamic discharge rate of between ?17 Mt a?1 and ?108 Mt a?1, with a mid-point estimate of ?55 Mt a?1, revising downward previous approximations. These velocities can be used as inputs for glacier flow models, and provide a baseline dataset against which future changes in ice dynamics can be detected.
DS1990-1500
1990
Van Wyck, N.Van Wyck, N., Valley, J.W., Austrheim, H.Oxygen isotope geochemistry of granulites and eclogites from the Bergenarc, southwest NorwayGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A347NorwayEclogites, Geochemistry
DS1991-1782
1991
Van Wyck, N.Van Wyck, N.Carbon and oxygen isotope ratios from carbonate bearing eclogites and calc-silicates from the Bergen arcs, NorwayGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 394NorwayEclogites, Geochronology
DS1996-1467
1996
Van Wyck, N.Van Wyck, N., Valley, J.W., Austrheim, H.Oxygen and carbon isotopic constraints on the development of eclogites, Holsnoy, Norway.Lithos, Vol. 38, No.3-4, Sept. 10, pp. 129-146.NorwayEclogites, Geochronology
DS1997-1198
1997
Van Wyck, N.Van Wyck, N., Johnson, C.M.Common lead Sm Sd and uranium-lead (U-Pb) constraints on petrogenesis, crustal architecture and tectonic setting of PenokeanGeological Society of America (GSA) Bulletin, Vol. 109, No. 7, pp. 799-808WisconsinPaleoproterozoic, geochronology, petrology, Penokean Orogeny
DS201212-0607
2012
Van Wyjk, K.Ruigrok, E., Mikesell, T.D., Van Wyjk, K.Scanning for velocity anomalies in the crust and mantle with diffractions from the core mantle boundary.Geophysical Research Letters, Vol. 39, L10301 5p.MantleGeophysics - seismics
DS1985-0122
1985
Van Wyk, E.Clark, T.C., Van Wyk, E.Inspection and classification of fluid inclusions within kimberlites and mantle derived xenolithsPetros, Vol. 12, pp. 9-12GlobalInclusions
DS201807-1517
2018
van Wyk, G.Musenwa, L., Khumalo, T., Kgaphola, M., Masemola, S., van Wyk, G.The new Culli nan AG milling circuit - a narrative of progress. MiningSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 45-64.Africa, South Africadeposit - Cullinan
DS202008-1425
2019
van Wyk, G.Musenwa, L., Khumalo, T., Kgaphola, M., Masemola, S., van Wyk, G.The new Cullinan AG milling circuit - a narrative of progress.The Journal of the Southern African Insitute of Mining and Metallurgy, Vol. 119, Feb. 10p. PdfAfrica, South Africadeposit - Cullinan

Abstract: In 2017, Petra Diamonds completed the construction and commissioning of a modern, fit-for-purpose diamond processing plant at Cullinan Diamond Mine (CDM). The design of CDM's milling circuit is unconventional in that it comprises an autogenous (AG) mill with a grate discharge with large ports, low-revolution jaw crushers, and high-pressure grinding roll crushers with large operating gaps. In this paper we review the design to provide guidance on what is expected from the milling circuit and to demonstrate how the design aims to address challenges experienced in the old plant, which was based on staged crushing technology. We assessed the performance of the CDM AG milling circuit from commissioning and early production stages to examine its impact along multiple dimensions. In the assessment we sought to understand the lessons from our milling circuit regarding diamond liberation, energy consumption, and the future of diamond processing as a whole.
DS200712-0109
2007
Van Wyk, H.Bristow, J., Van Wyk, H., Norton, G., Stevens, G., Oosterveldt, T.Alluvial diamond deposits of the Lower Vaal and Middle Orange Rivers (MOR) and their exploitation. Rockwell Diamonds Inc. promotional presentation.Diamonds in Kimberley Symposium & Trade Show, Bristow and De Wit held August 23-24, Kimberley, South Africa, GSSA Diamond Workshop CD slides 27Africa, South AfricaProjects
DS1982-0377
1982
Van wyk, J.A.Loubser, J.H.N., Van wyk, J.A., Welbourn, C.M.Electron resonance of a tri nitrogen centre in Cape Yellow Type1AdiamondsJournal of Phys. Solid State Physics, Vol. 15, No. 29, pp. 6031-6036GlobalDiamond Morphology
DS1987-0426
1987
Van Wyk, J.A.Loubser, J.H.N., Van Wyk, J.A.ESR centers in type II diamondsSouth African Journal of Phys, Vol. 10, No. 4, pp. 165-168GlobalBlank
DS1986-0829
1986
Van Wyk, J.P.Van Wyk, J.P., Menaar, L.F.Diamondiferous gravels of the lower Orange River, NamaqualandIn: Mineral deposits of Southern Africa, Vol. 2, pp. 2309-2322South AfricaPlacers
DS200812-0722
2008
Van Wyk de Vries, B.Mathieu, L., Van Wyk de Vries, B., Holohan, E.P., Troll, V.R.Dykes, cups, saucers, sills: analogue experiments on magma intrusion into brittle rocks.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 1-13.MantleMagmatism
DS200812-0723
2008
Van Wyk de Vries, B.Mathieu, L., Van Wyk de Vries, B., Holohan, E.P., Troll, V.R.Dykes, cups, saucers and sills: analogue experiments on magma intrusion into brittle rocks.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 1-13.MantleMagmatism
DS1988-0430
1988
Van Wyx, J.A.Madiba, C.C.P., Sellschop, J.P.F., Van Wyx, J.A.Light volatiles in synthetic diamond analyzed by ion probesNucl. Instrum. Methods Phys. Res. Sect. B., Vol. B35, No. 3-4, 12(II) pp. 442-445GlobalDiamond synthesis
DS200812-1215
2008
Van Zele, M.A.Vizan, H., Van Zele, M.A.Jurassic Cretaceous intermediate virtual geomagnetic poles Pangean subduction zones.Earth and Planetary Science Letters, Vol. 266, 1-2, pp. 1-13.MantleSubduction
DS1970-0696
1973
Van zijl, J.S.V.Gough, D.I., De beer, J.H., Van zijl, J.S.V.A Magnetometer Array Study in Southern AfricaRoy. Astron. Soc. Geophys. Journal, Vol. 34, PP. 421-433.South Africa, BotswanaGeophysics
DS1975-0064
1975
Van Zijl, J.S.V.De beer, J.H., Gough, D.I., Van Zijl, J.S.V.An Electrical Conductivity Anomaly and Rifting in Southern Africa. #1Nature., Vol. 225, PP. 678-680.South Africa, BotswanaGeophysics, Tectonics
DS1975-0268
1976
Van zijl, J.S.V.De beer, J.H., Van zijl, J.S.V., Huyssen, R.M.J., Hugo, P.L.V.A Magnetometer Array Study in Southwest Africa, Botswana And Rhodesia.Roy. Astron. Soc. Geophys. Journal, Vol. 45, PP. 1-17.Southwest Africa, Namibia, Botswana, ZimbabweGeophysics
DS202011-2039
2020
van Zuilen, K.Gress, M.U., Koorneef, J.M., Thomassot, E., Chinn, I.L., van Zuilen, K., Davies, G.R.Sm-Nd isochron ages coupled with C-N isotope data of eclogitic diamonds from Jwaneng, Botswana.Geochimica et Cosmochimica Acta, 10.1016/j.gca.2020.10.010 35p. PdfAfrica, Botswanadeposit - Jwaneng

Abstract: Constraining the formation age of individual diamonds from incorporated mineral inclusions and assessing the host diamonds’ geochemical characteristics allows determination of the complex history of diamond growth in the sub-continental lithospheric mantle (SCLM). It also provides the rare opportunity to study the evolution of the deep cycling of volatiles over time. To achieve these aims, Sm-Nd isotope systematics are presented for 36 eclogitic garnet and clinopyroxene inclusions from 16 diamonds from the Jwaneng mine, Botswana. The inclusions and host diamonds comprise at least two compositional suites that record different ‘mechanisms’ of diamond formation and define two isochrons, one Paleoproterozoic (1.8 Ga) and one Neoproterozoic (0.85 Ga). There are indications of at least three additional diamond-forming events whose ages currently cannot be well constrained. The Paleoproterozoic diamond suite formed by large-scale (> 100’s km), volatile-rich metasomatism related to formation and re-working of the Proto-Kalahari Craton. In contrast, the heterogeneous composition of the Neoproterozoic diamond suite indicates diamond formation on a small-scale, through local (< 10 km) equilibration of compositionally variable diamond-forming fluids in different eclogitic substrates during the progressive breakup of the Rodinia supercontinent. The results demonstrate that regional events appear to reflect the input of volatiles (i.e., carbon-bearing) derived from the asthenospheric mantle, whereas local diamond-forming events mainly promote the redistribution of volatiles within the SCLM. The occurrence of isotopically light carbon analysed in distinct growth zones from samples of this study (?13C < -21.1‰) provides further indication of a recycled origin for surface-derived carbon in some diamonds from Jwaneng. Determining Earth’s long-term deep carbon cycle using diamonds, however, requires an understanding of the nature and scale of specific diamond-forming events.
DS202103-0382
2021
van Zuilen, K.Gress, M.U., Koornneef, J.M., Thomassot, E., Chinn, I.L., van Zuilen, K., Davies, G.R.Sm-Nd isochron age coupled with C-N isotope data of eclogitic diamonds from Jwaneng, Botswana.Geochimica et Cosmochimica Acta, Vol. 293, pp. 1-17. pdfAfrica, Botswanadeposit - Jwaneng

Abstract: Constraining the formation age of individual diamonds from incorporated mineral inclusions and assessing the host diamonds’ geochemical characteristics allows determination of the complex history of diamond growth in the sub-continental lithospheric mantle (SCLM). It also provides the rare opportunity to study the evolution of the deep cycling of volatiles over time. To achieve these aims, Sm-Nd isotope systematics are presented for 36 eclogitic garnet and clinopyroxene inclusions from 16 diamonds from the Jwaneng mine, Botswana. The inclusions and host diamonds comprise at least two compositional suites that record different ‘mechanisms’ of diamond formation and define two isochrons, one Paleoproterozoic (1.8?Ga) and one Neoproterozoic (0.85?Ga). There are indications of at least three additional diamond-forming events whose ages currently cannot be well constrained. The Paleoproterozoic diamond suite formed by large-scale (>100?s km), volatile-rich metasomatism related to formation and re-working of the Proto-Kalahari Craton. In contrast, the heterogeneous composition of the Neoproterozoic diamond suite indicates diamond formation on a small-scale, through local (<10?km) equilibration of compositionally variable diamond-forming fluids in different eclogitic substrates during the progressive breakup of the Rodinia supercontinent. The results demonstrate that regional events appear to reflect the input of volatiles (i.e., carbon-bearing) derived from the asthenospheric mantle, whereas local diamond-forming events mainly promote the redistribution of volatiles within the SCLM. The occurrence of isotopically light carbon analysed in distinct growth zones from samples of this study (?13C?
DS1975-0065
1975
Van Zyjl, J.S.V.De beer, J.H., Gough, D.I., Van Zyjl, J.S.V.An Electrical Conductivity Anomaly and Rifting in Southern Africa. #2Nature., Vol. 255, JUNE 26TH, PP. 678-680.BotswanaGeotectonics, Geophysics
DS1995-1972
1995
Van Zyl, A.A.Van Zyl, A.A.The Mwadui kimberlite, TanzaniaYellowknife 95, program and abstracts, Sept. 6-8, p. 43-44.TanzaniaGeochronology, mining, Deposit -Mwadui
DS1960-0307
1962
Van zyl, C.Van zyl, C.Mineralogical Report on Sand Samples Collected between Moshaneng and Kang, Bechuana land Protectorate.Cen. Metallurg. Lab., (UNPUBL.)BotswanaDiamond Prospecting
DS1960-0777
1967
Van zyl, C.Allsop, H.L., Burger, A.J., Van zyl, C.A Minimum Age for the Premier Kimberlite Pipe Yielded by Biotite Rubidium-strontium (rb-sr) Measurements, with Related Galena Isotopic Data.Earth and Planetary Science Letters, Vol. 3, No. 2, PP. 161-166.South AfricaGeochronology, Isotope
DS1992-1597
1992
Van Zyl, D.Van Zyl, D., Koval, M., Li, Ta M.Risk assessment -management issues in the environment planning of MinesSociety Mining Engineers and Exploration Inc, 230p. approximately $ 60.00United StatesMining, Assessment, environment, audits
DS202006-0954
2020
Van Zyl, H.J.Van Zyl, H.J., Bam, W.G., Steenkamp, J.D.Identifying barriers to growth in mineral value chains. ( not specific to diamonds)Journal of the Southern African Institute of Mining and Metallurgy, 8p. PdfAfrica, South Africalegal

Abstract: Despite the importance that barrier identification has for policy-making and industry stakeholders alike; little guidance exists on consistent processes to systematically identify barriers that are hindering the different sectors of a value chain’s expansion and growth. This article describes the development of a framework that supports the identification of barriers to growth in mineral value chains. The resultant process was applied to the case of the manganese value chain in South Africa, and revealed 31 barriers within this industry. The results were validated by a panel of experts and the feedback was used to rework and improve the framework.
DS1986-0072
1986
Van Zyl, V.C.Beukes, G.J., Van Zyl, V.C., et al.A hogbomite spinel gedrite paragenesis from northern Busnmanland, Namaqua Mobile Belt, South AfricaNeues Jahrbuch f?r Mineralogie, Vol. 155, No. 1, pp. 53-66South AfricaMineralogy, Analyses
DS200612-1470
2006
Vanacore, E.Vanacore, E., Niu, F., Kawakatsu, H.Observations of the mid-mantle discontinuity beneath Indonesia from S to P converted waveforms.Geophysical Research Letters, Vol. 33, 4, Feb. 28, L04302Asia, IndonesiaGeophysics - seismic
DS200812-0654
2008
Vanacore, E.Li, J., Chen, Q.F., Vanacore, E., Niu, F.Topography of the 660 km discontinuity beneath northeast China: implications for a retrograde motion of the subducting Pacific Slab.Geophysical Research Letters, Vol. 35, 1, L01302.ChinaSubduction
DS1990-1215
1990
Vanangamudi, M.Rao, T.C., Vanangamudi, M., Barnwal, J.P.Industrial application of heavy medium cyclone modelAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Meeting, Salt Lake City, February 26, Preprint?GlobalHeavy medium Application, Mineral processing -gener
DS1990-0963
1990
VanArsdale, R.Luzietti, E.A., Schweig, E.S., VanArsdale, R.A seismic reflection survey of Crittenden County, fault, northeastArkansawEos, Vol. 71, No. 43, October 23, p. 1435 AbstractArkansasGeophysics -seismics, Fault
DS1991-1530
1991
Vanarsdale, R.B.Schwieg, E.S., Vanarsdale, R.B., Burroughs, R.K.Subsurface structure in the vicinity of an intraplate earthquake swarm, central ArkansawTectonophysics, Vol. 186, No. 1-2, February 1, pp. 107-114ArkansasBlank
DS1990-0365
1990
Vanbreemen, O.Corriveau, L., Heaman, L.M., Marcantonio, F., Vanbreemen, O.1.1 GA potassium-rich alkaline plutonism in the southwest Grenville province-Contributions to Mineralogy and Petrology, Vol. 105, No. 4, pp. 473-485OntarioAlkaline rocks, Geochronology
DS1990-1501
1990
Vance, D.Vance, D., O'Nions, R.K.Isotopic chronometry of zoned garnets: growth kinetic sand metamorphichistoriesEarth and Planetary Science Letters, Vol. 97, No. 3/4, March pp. 227-240GlobalGarnets, Petrology -isotopes
DS1998-1519
1998
Vance, D.Vance, D., Meier, M., Oberli, F.The influence of high uranium-thorium (U-Th) inclusions on the uranium-thorium-lead systematics of almandine pyrope garnet: resultsGeochimica et Cosmochimica Acta, Vol. 62, No. 21-22, pp. 3527-40.IndiaGarnet mineralogy - not specific to diamonds
DS2000-0779
2000
Vance, D.Prince, C.I., Kosler, J., Vance, D., Gunther, D.Comparison of laser ablation ICP MS and isotope dilution rare earth elements (REE) analyses - Smneodymium garnet geochronology.Chemical Geology, Vol. 168, No. 3-4, Aug. 1, pp. 255-74.GlobalGarnet chronology - crystal, Age determination, dating, light rare earth element (LREE) enriched minerals
DS1970-0523
1972
Vance, E.R.Harris, J.W., Vance, E.R.Induced Graphitization Around Crystalline Inclusions in DiamondContributions to Mineralogy and Petrology, Vol. 35, pp. 227-34.South Africa, West Africa, Sierra Leone, GhanaPetrology, Deposit - Premier, Finsch, Jagersfontein
DS1970-0841
1973
Vance, E.R.Vance, E.R., Harris, J.W., Milledge, H.J.Possible Origins of Alpha Damage in Diamonds from Kimberlite and Alluvial Sources.Mineralogical Magazine., Vol. 39, No. 303, PP. 349-360.South AfricaFinsch, Bellsbank, Premier, De Beers
DS1970-0923
1974
Vance, E.R.Harris, J.W., Vance, E.R.Studies of the Reaction Between Diamond and Heated KimberlitContributions to Mineralogy and Petrology, Vol. 47, No. 4, PP. 231-244.South AfricaMineral Chemistry, Petrology
DS1989-1475
1989
Vandall, T.A.Symons, D.T.A., Vandall, T.A.The Kapuskasing structural zone: paleomagnetic evidence for early Proterzoic faulting and upliftGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A123. (abstract.)OntarioTectonics, Kapuskasing Zone
DS1990-1502
1990
Vandall, T.A.Vandall, T.A., Symons, D.T.A.Paleomagnetism of Archean granites and Matachewan dikes in the Wawasubprovince, Ontario: reevaluation of the Archean apparent polar wander pathCanadian Journal of Earth Sciences, Vol. 27, No. 8, August pp. 1031-1039OntarioGeophysics -paleomagnetics, Matachewan dikes
DS2001-0978
2001
Vandamme, D.Riisager, J., Perrin, M., Riisage, P., Vandamme, D.Paleomagnetic results and paleointensity of Late Cretaceous Madagascan basaltJournal of African Earth Science, Vol. 32, No. 3, Apr. pp. 503-18.MadagascarBasalts
DS1993-0154
1993
Vandebeek, R.R.Boyle, D.R., Cox, D.L., Vandebeek, R.R.Groundwater sampling methodology for mineral exploration in glaciated terrain using reverse circulation overburden drillingJournal of Geochemical Exploration, Vol. 49, No. 3, December pp. 213-231Ontario, QuebecOverburden drilling -review of techniques, Geochemistry
DS1997-0073
1997
VanDecarBank, C.G., Bostock, M.G., Ells, R.M., VanDecar, HajnalLithospheric mantle structure beneath the Trans Hudson Orogen from teleseismic travel time inversion.Lithoprobe Report, No. 62, pp. 6-9.ManitobaGeophysics - seismics, Tectonics
DS2001-0325
2001
VanDecarFouch, M.J., James, Silver, VanDecar, Van der LeeImaging broad ranges in structural variations beneath the Kaapvaal and Zimbabwe Cratons, southern Africa.Slave-Kaapvaal Workshop, Sept. Ottawa, 5p. abstractSouth Africa, ZimbabweGeophysics - seismics, Tomography - Kimberley array
DS1993-1112
1993
VanDecar, J.Nataf, H.C., VanDecar, J.Seismological detection of a mantle plume?Nature, Vol. 364, No. 6433, July 8, pp. 115-120MantleGeophysics -seismics, Hotspot
DS2000-0440
2000
Vandecar, J.James, D., Fouch, M., Vandecar, J.Seismic studies of lithsopheric structure beneath southern Africa: implications for formation cratons...Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-163.South AfricaCraton - evolution Kaapvaal, Geophysics - seismics
DS1998-0074
1998
VanDecar, J.C.Bank, C.G., Bostock, M.G., VanDecar, J.C.Lithospheric mantle structure beneath the Trans Hudson Orogen and The origin of Diamondiferous kimberlitesá#2Journal of Geophysical Research, Vol. 103, No. 5, May 10, pp. 10103-114.Saskatchewan, Manitoba, Northwest TerritoriesKimberlites, Trans Hudson Orogen
DS2002-1732
2002
VanDecarm J.C.Wolfe, C.J., Bjarnson, I.T., VanDecarm J.C., Solomon, S.Assessing the depth resolution of tomographic models of upper mantle structure beneath Iceland.Geophysical Research Letters, Vol.29, 2, pp. 21-4.IcelandTomography, Geophysics - seismics
DS200512-0569
2005
Vandenabeele, P.Korsakov, A.V., Vandenabeele, P., Theunissen, K.Discrimination of metamorphic diamond populations by Raman spectroscopy ( Kokchetav Kazakhstan).Spectrochimica Acta Part A, Vol. 61, 10, pp. 2378-2385.RussiaMetamorphic diamonds
DS201012-0407
2010
Vandenabeele, P.Korsakov, A.V., Zhukov, V.P., Vandenabeele, P.Raman based geobarometry of ultrahigh pressure metamorphic rocks: applications, problems and perspectives.Analytical and Bioanalytical Chemistry, Vol. 397, 7, pp. 1618-2641-50.TechnologyCoesite
DS1994-1863
1994
Vandenbe, A.P.Vlaar, N.J, Vankeken, P.E., Vandenbe, A.P.Cooling of the earth in the Archean -consequences of pressure release melting in a hotter mantle.Earth and Planetary Sciences, Vol. 121, No. 1-2, January pp. 1-18.MantleMelting
DS1996-1449
1996
Vandenberg, A.H.M.Turner, S.P., Kelley, S.P., Vandenberg, A.H.M., et al.Source of the Lachlan fold belt flysch linked to convective removal of the lithospheric mantle ...beltGeology, Vol. 24, No. 10, Oct. pp. 941-944Australia, AntarcticaMantle, Delamarian Ross fold belt, Geochronology, comparison
DS1999-0765
1999
Vandenberg, A.H.M.Vandenberg, A.H.M.Timing of orogenic events in the Lachlan Orogen (1999)Australian Journal of Earth Sciences, Vol. 46, No. 5, Oct. pp. 691-702.AustraliaTectonics, Orogeny - Lachlan
DS2001-1184
2001
VandenBerg, A.P.Van Hunen, J., VandenBerg, A.P., Vlaar, N.J.Latent heat effects of the major mantle phase transitions on low angle subduction.Earth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 125-35.MantleSubduction
DS200612-1469
2005
VandenBerg, A.P.Van Thielen, P., VanSummeren, J., VanderHilst, R.D., VandenBerg, A.P., Vlaar, N.J.Numerical study of the origin and stability of chemically distinct reservoirs deep in the Earth's mantle.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 117-136.MantleGeochemistry
DS200912-0790
2009
Vandenberg, A.P.Van Summeren, J.R., Vandenberg, A.P., Van der Hilst, R.D.Upwellings from a deep mantle reservoir filtered at the 660 km phase transition in thermochemical convection models and implications for intra-plate volcanism.Physics of the Earth and Planetary Interiors, Vol. 172, 3-4, pp. 210-224.MantleGeothermometry
DS201510-1811
2015
Vandenberg, J.A.Vandenberg, J.A., Herrell, M., Faithful, J.W., Snow, A.M., Lacrampe, J., Bieber, C., Dayyani, S., Chisholm, V.Multiple modeling approach for the aquatic effects assessment of a proposed northern diamond mine development. Gahcho KueMine Water and the Environment, in press available, 19p.Canada, Northwest TerritoriesDeposit - Gahcho Kue

Abstract: Eight water models were used to assess potential aquatic environmental effects of the proposed Gahcho Kué diamond mine on groundwater and surface water flow and quality in the Northwest Territories, Canada. This sequence of models was required to cover different spatial and temporal domains, as well as specific physico-chemical processes that could not be simulated by a single model. Where their domains overlapped, the models were interlinked. Feedback mechanisms amongst models were addressed through iterative simulations of linked models. The models were used to test and refine mitigation plans, and in the development of aquatic component monitoring programs. Key findings generated by each model are presented here as testable hypotheses that can be evaluated after the mine is operational. This paper therefore offers a record of assumptions and predictions that can be used as a basis for post-validation.
DS201609-1754
2016
Vandenberg, J.A.Vandenberg, J.A., Herrell, M., Faithful, J.W., Snow, A.M., Lacrampe, J., Bieber, C., Dayyani, S., Chisholm, V.Multiple modeling approach for the aquatic effects assessment of a proposed northern diamond mine development.Mine Water and the Environment, Vol. 35, pp. 350-368.Canada, Northwest TerritoriesDeposit - Gahcho Kue

Abstract: Eight water models were used to assess potential aquatic environmental effects of the proposed Gahcho Kué diamond mine on groundwater and surface water flow and quality in the Northwest Territories, Canada. This sequence of models was required to cover different spatial and temporal domains, as well as specific physico-chemical processes that could not be simulated by a single model. Where their domains overlapped, the models were interlinked. Feedback mechanisms amongst models were addressed through iterative simulations of linked models. The models were used to test and refine mitigation plans, and in the development of aquatic component monitoring programs. Key findings generated by each model are presented here as testable hypotheses that can be evaluated after the mine is operational. This paper therefore offers a record of assumptions and predictions that can be used as a basis for post-validation.
DS201906-1301
2019
Vander Auwera, J.Higgins, M., Bedard, L.P., dos Santos, E., Vander Auwera, J.Lamprophyres, carbonatites and phoscorites of the Saguenay City alkali province, Quebec, CanadaGAC/MAC annual Meeting, 1p. Abstract p. 108.Canada, QuebecCcrbonatite

Abstract: The Saguenay City alkali province (~ 580 Ma) comprises the Saint-Honoré alkaline complex (carbonatite-syenite), lesser-known minor subsurface carbonatite intrusions and several sets of lamprophyre (sl) dykes. Flat-lying, north-dipping dykes (l-100 cm) that crop out close the Saguenay River/Fjord were formed by multiple intrusions of a very fluid magma. The dykes are continuously variable in composition from carbonatite to ultramafic lamprophyre. Olivine phenocrysts (l-3 mm) are pseudomorphed by serpentine but phlogopite phenocrysts (l-5 mm) are well preserved in a matrix of a fine-grained serpentine, chlorite and carbonate. A few dykes are phoscorites, with abundant phenocrysts of phlogopite, oxides, apatite and accessory baddeleyite. In all dykes, the matrix may have been originally fine-grained or even glassy, and subsequently altered by water dissolved in the original magma. Several dykes contain abundant xenoliths: mostly crustal and possibly one of mantle origin. Low-carbonate dykes have a narrow range in Sr isotopes (0.7030-0.7033) versus the wider range of high-carbonate dykes (0.7032-0.7046), but this distinction is not seen in ?Nd (3.4-4.9). Overall, it appears that each batch of magma was small and came from independent mantle sources. Recently, we found a new set of vertical, NW-directed lamprophyres around the Baie des Ha! Ha!, about 15 km south of the main swarm. They have phlogopite phenocrysts to 50 mm and olivine pseudomorphs. Their contrasting orientation suggests that they have a different age to the Saguenay River dykes, but they have yet to be dated. The overall pattern is of an extensive mantle source that delivered small volumes of volatile-rich ultramafic magmas over a long period. We consider that some of these magma batches accumulated and differentiated in a magma chamber beneath the Saint-Honoré alkaline complex, whereas others rose uninterrupted to high levels of the crust where they were emplaced as dykes.
DS200812-0661
2008
Vander Hilst, R.Li,C., Vander Hilst, R., Meltzer, A.S., Engdahl, E.R.Subduction of the Indian lithosphere beneath the Tibetan Plateau and Burma.Earth and Planetary Science Letters, Vol. 274, 1-2, pp. 157-168.Asia, Tibet, MyanmarSubduction
DS201810-2353
2018
vander Neut, J.Matias, M.M.A., vander Neut, J.Marchenko imaging by unidimensional deconvolution.Geophysical Prospecting, doi.10.111/1365-2478.12686Mantlegeophysics

Abstract: Obtaining an accurate image of the subsurface still remains a great challenge for the seismic method. Migration algorithms aim mainly on positioning seismic events in complex geological contexts. Multiple reflections are typically not accounted for in this process, which can lead to the emergence of artefacts. In Marchenko imaging, we retrieve the complete up? and downgoing wavefields in the subsurface to construct an image without such artefacts. The quality of this image depends on the type of imaging condition that is applied. In this paper, we propose an imaging condition that is based on stabilized unidimensional deconvolution. This condition is computationally much cheaper than multidimensional deconvolution, which has been proposed for Marchenko imaging earlier. Two specific approaches are considered. In the first approach, we use the full up? and downgoing wavefields for deconvolution. Although this leads to balanced and relatively accurate amplitudes, the crosstalk is not completely removed. The second approach is to incorporate the initial focussing function in the deconvolution process, in such a way that the retrieval of crosstalk is avoided. We compare images with the results of the classical cross?correlation imaging condition, which we apply to reverse?time migrated wavefields and to the up? and downgoing wavefields that are retrieved by the Marchenko method.
DS2002-1603
2002
Vander PluijmTohver, E., Vander Pluijm, Vander Voo, RizzottoPaleogeography of the Amazon Craton at 1.2 Ga: early Grenvillian collision with Llano segment of Laurentia.Earth and Planetary Science Letters, Vol.199,1-2,pp.185-200., Vol.199,1-2,pp.185-200.BrazilTectonics, Laurentia
DS2002-1604
2002
Vander PluijmTohver, E., Vander Pluijm, Vander Voo, RizzottoPaleogeography of the Amazon Craton at 1.2 Ga: early Grenvillian collision with Llano segment of Laurentia.Earth and Planetary Science Letters, Vol.199,1-2,pp.185-200., Vol.199,1-2,pp.185-200.BrazilTectonics, Laurentia
DS2002-1603
2002
Vander VooTohver, E., Vander Pluijm, Vander Voo, RizzottoPaleogeography of the Amazon Craton at 1.2 Ga: early Grenvillian collision with Llano segment of Laurentia.Earth and Planetary Science Letters, Vol.199,1-2,pp.185-200., Vol.199,1-2,pp.185-200.BrazilTectonics, Laurentia
DS2002-1604
2002
Vander VooTohver, E., Vander Pluijm, Vander Voo, RizzottoPaleogeography of the Amazon Craton at 1.2 Ga: early Grenvillian collision with Llano segment of Laurentia.Earth and Planetary Science Letters, Vol.199,1-2,pp.185-200., Vol.199,1-2,pp.185-200.BrazilTectonics, Laurentia
DS1985-0693
1985
Vanderbilt, H.L.Vanderbilt, H.L.Herkimer Diamonds #1Lapidary Journal, Vol. 39, No. 7, October pp. 45-47GlobalDiamond Morphology
DS1989-1562
1989
Vanderbo.., C.A.Vohra, Y.K., Vanderbo.., C.A., Desgreni.., S., Ruoff, A.L.Near-infrared photoluminescence bands in diamond. (Technical note)Phys. Rev. B., Vol. 39, No. 8, March 15, pp. 5464-5467GlobalDiamond morphology
DS1991-1475
1991
Vanderbose, C.Ruoff, A., Luo, H., Vanderbose, C., Vohra, YkGenerating near earth core pressures with Type IIA diamondsApplied Phys. Letters, Vol. 59, np. 2, November 18, pp. 2681-2682MantleDiamond morphology, Experimental petrology
DS1998-1520
1998
Vanderhaege, O.Vanderhaege, O., Ledru, P., Milesi, J.P.Contrasting mechanism of crustal growth. Geodynamic evolution of Paleoproterozoic granite - greenstone beltPrecambrian Research, Vol. 92, No. 2, Oct.l, pp. 165-94GlobalTectonics, Greenstone belts
DS2000-0443
2000
VanderhaegheJamieson, R.A., Beaumont, Vanderhaeghe, FullsackHow does the lower crust get hot?Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 2p. abstract.MantleMagma - heat production
DS2001-0973
2001
Vanderhaeghe, O.Rey, P., Vanderhaeghe, O., Teyssier, C.Gravitational collapse of the continental crust: definition, regimes and modesTectonophysics, Vol. 342, No. 3-4, Dec. pp. 435-49.MantleGeophysics - gravity
DS2001-1192
2001
Vanderhaeghe, O.Vanderhaeghe, O., Teyssier, C.Crustal scale rheological transitions during late orogenic collapseTectonophysics, Vol. 339, No. 1-2, pp. 211-28.GlobalTectonics
DS2001-1193
2001
Vanderhaeghe, O.Vanderhaeghe, O., Teyssier, C.Partial melting and flow of orogensTectonophysics, Vol. 342, No. 3-4, pp. 451-72.MantleMelting, Orogeny, tectonics
DS201012-0813
2010
Vanderhaeghe, O.Vanderhaeghe, O., Duchene, S.Crustal scale mass transfer, geotherm and topography at convergent plate.Terra Nova, Vol. 22, 5, October pp. 315-323.MantleSubduction
DS201212-0748
2012
Vanderhaeghe, O.Vanderhaeghe, O.The thermal-mechanical evolution of crustal orogenic belts at convergent plate boundaries: a reappraisal of the orogenic cycle.Journal of Geodynamics, Vol. 56-57, pp. 124-145.MantleGeothermometry
DS1860-0367
1881
Vanderheym, E.Jannettaz, E., Fontenay, E., Vanderheym, E., Coutance, A.Diamant et Pierres Precieuses. Cristall. Descript. Emplois, evaluation.Paris:, 580P. SECOND EDITION.GlobalGemology
DS200612-1469
2005
VanderHilst, R.D.Van Thielen, P., VanSummeren, J., VanderHilst, R.D., VandenBerg, A.P., Vlaar, N.J.Numerical study of the origin and stability of chemically distinct reservoirs deep in the Earth's mantle.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 117-136.MantleGeochemistry
DS200812-0943
2008
VanderkluysenRay, R., Shukia, A.D., Sheth, H.C., Ray, J.S., Duraiswami, Vanderkluysen, Rautela, MallikHighly heterogeneous Precambrian basement under the central Deccan Traps, India: direct evidence from xenoliths in dykes.Gondwana Research, Vol. 13, 3, pp. 375-385.IndiaPetrology - dykes
DS2001-0528
2001
VanderleeJames, D.E., Fouch, D.J., Van De Car, M.J., VanderleeTectosphere structure beneath southern AfricaGeophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2485-88.South AfricaTectonics
DS1994-1833
1994
Vandersande, J.W.Vandersande, J.W.Thermal conductivity of natural isotope diamondProperties and growth of diamond, G. Davies, pp. 33-35.GlobalDiamond, Bulk properties of natural isotope diamond
DS1994-1834
1994
Vandersande, J.W.Vandersande, J.W.Effect of nitrogen on the thermal conductivity of diamondProperties and growth of diamond, G. Davies, pp. 103-105.GlobalDiamond, Properties of nitrogen in diamond
DS2002-0464
2002
VandersteldtFoden, J., Song, Turner, Elburg, Smith, VandersteldtGeochemical evolution of lithospheric mantle beneath southeast South AustraliaChemical Geology, Vol.182, 2-4, Feb.15, pp.663-95.Southeast AustraliaGeochemistry
DS1995-1973
1995
Vanderveen, A.H.Vanderveen, A.H.Chromian spinel mineralogy of the Stare Ransko gabbro peridotite Czech-Republic and its implications -sulfideMineralium Deposita, Vol. 25, pp. 355-391GlobalMineralogy, Peridotite
DS2000-0258
2000
VanderVelden, A.Eaton, D.W., Ross, G.M., Cook, F.A., VanderVelden, A.Seismic imaging of the upper mantle beneath the Rocky Mountain foreland, southwestern Alberta.Canadian Journal of Earth Sciences, Vol.37, No.11, Nov.pp.1493-07.Alberta, southwesternTectonics, Geophysics - seismics
DS1995-1974
1995
Vandervoot, D.S.Vandervoot, D.S., Jordan, R.E., Zeitler. P.K., Alonso, R.N.Chronology of internal drainage and uplift southern Puna plateau, Argentine central AndesGeology, Vol. 23, No. 2, Feb. pp. 145-148Andes, ArgentinaGeochronology, Tectonics
DS201807-1516
2018
Vanderzee, S.Mervine, E.M., Wilson, S.A., Power, I.M., Dipple, G.M., Turvey, C.C., Hamilton, J.L., Vanderzee, S., Raudsepp, M., Southam, C., Matter, J.M., Kelemen, P.B., Stiefenhofer, J., Miya, Z., Southam, G.Potential for offsetting diamond mine carbon emissions through mineral carbonation of processed kimberlite: an assessment of De Beers mine sites in South Africa and Canada.Mineralogy and Petrology, 10.1007/ s00710-018- 0589-4, 14p.Africa, South Africa, Canada, Northwest Territories, Ontariodeposit - Venetia, Voorspoed, Gahcho Kue, Victor, Snap Lake

Abstract: De Beers kimberlite mine operations in South Africa (Venetia and Voorspoed) and Canada (Gahcho Kué, Victor, and Snap Lake) have the potential to sequester carbon dioxide (CO2) through weathering of kimberlite mine tailings, which can store carbon in secondary carbonate minerals (mineral carbonation). Carbonation of ca. 4.7 to 24.0 wt% (average?=?13.8 wt%) of annual processed kimberlite production could offset 100% of each mine site’s carbon dioxide equivalent (CO2e) emissions. Minerals of particular interest for reactivity with atmospheric or waste CO2 from energy production include serpentine minerals, olivine (forsterite), brucite, and smectite. The most abundant minerals, such as serpentine polymorphs, provide the bulk of the carbonation potential. However, the detection of minor amounts of highly reactive brucite in tailings from Victor, as well as the likely presence of brucite at Venetia, Gahcho Kué, and Snap Lake, is also important for the mineral carbonation potential of the mine sites.
DS201312-0249
2013
Van-Dunem, V.Ernst, R.E., Pereira, E., Hamilton, M.A., Pisarevsky, S.A., Rodriques, J., Tasinari, C.C.G., Teixeira, W., Van-Dunem, V.Mesoproterozoic intraplate magmatic 'barcode' record of the Angola portion of the Congo craton: newly dated magmatic events at 1505 and 1110 Ma and implications for Nuna ( Columbia) supercontinent reconstructions.Precambrian Research, Vol. 230, pp. 103-118.Africa, AngolaMagmatism
DS2000-0883
2000
Vaneca, J.G.Sgarbi, P.B.A., Gaspar, J.C., Vaneca, J.G.Clinopyroxene from Brazilian kamafugitesLithos, Vol. 53, No. 2, Aug. pp. 101-16.BrazilKamafugites - Santo Antonia da Barra, Mata da Corda, Petrology
DS1994-1835
1994
Vanecek, M.Vanecek, M.Mineral deposits of the worldElesvier Science, 520p. approx. $ 220.00GlobalBook -ad, Mineral deposits
DS1994-1836
1994
Vanecek, M.Vanecek, M.Mineral deposits of the world: ores industrial minerals and rocksElsevier, Dev. Economic Geology No. 28, 550pGlobalBook -table of contents, Mineral deposits
DS1994-1837
1994
Vanecek, M.Vanecek, M.Principal trends in exploiting the world's mineral wealthMineral deposits of the world, ores, Elsevier, Vol. 28, pp. 427-453.GlobalDiamonds mentioned, Industrial minerals
DS1994-1838
1994
Vanecek, M.Vanecek, M.Mineral deposits of North AsiaMineral Deposits of the World, Dev. Economic Geology # 28, pp. 108-171GlobalMetallogeny, Deposits -overview, review
DS1991-0663
1991
Vanek, J.Hanus, V., Vanek, J.Paleoplates buried in the upper mantle and the cyclic character ofsubductionJournal of Geodynamics, Vol. 13, No. 1, No. 2-4, pp. 29-45South America, AndesGeophysics -seismics, Mantle, tectonics
DS1994-1839
1994
Vanek, J.Vanek, J., Vankova, V., Hanus, V.Geochemical zonation of volcanic rocks and deep structure of Ecuador and southern ColombiaJournal of South American Earth Sciences, Vol. 7, No. 1, pp. 57-67GlobalGeochemistry, Tectonics, Structure
DS1996-0594
1996
Vanek, J.Hanus, V., Vanek, J.Cyclic evolution of convergent plate margins indicated by time sequence of volcanism and subductionGlobal Tectonics and Metallogeny, Vol. 5, No. 3-4, p. 103-108AndesWadati-Benioff zone, volcanism.
DS1988-0725
1988
Vanenckevort, W.J.P.Vanenckevort, W.J.P., Lochs, H.G.M.Photoluminescence determination of the nitrogen a -defect content indiamonds.(Russian)Journal of Applied Physics, Vol. 64, No. 1, July 1, pp. 436-437GlobalDiamond synthesis, Photoluminescence
DS1990-1503
1990
Vaneneckevort, W.J.P.Vaneneckevort, W.J.P., Visser, E.P.Photoluminesence microtomography of diamondPhil. Magazine B., Vol. 62, No. 6, December pp. 597-614GlobalDiamond morphology, Luminesence
DS200512-1126
2004
Vangeren, L.Vangeren, L., Deschamps, F., Van der Hilst, R.D.Geophysical evidence for chemical variations in the Australian continental mantle.Geophysical Research Letters, Vol. 31, 17, Sept. 16, L17607AustraliaGeophysics - geochemistry
DS200512-1094
2005
Vanhaecke, F.Tomlinson, E., De Schrijver, I., De Corte, K., Jones, A.P., Moens, L., Vanhaecke, F.Trace element compositions of submicroscopic inclusions in coated diamond: a tool for understanding diamond petrogenesis.Geochimica et Cosmochimica Acta, Vol. 69, 19, Oct. 1, pp. 4719-4732.Africa, Democratic Republic of CongoSilicate melt inclusions, Group 1, diamond inclusions
DS201412-0299
2014
Vanhaecke, F.Glorie, S., Zhimulev, F.I., Buslov, M.M., Andersen, T., Plavsa, D., Izmer, A., Vanhaecke, F., De Grave, J.Formation of the Kokchetav subduction collision zone - northern Kazakhstan : insights from zircon U-Pb and Lu-Hf isotope systematics.Gondwana Research, Vol. 27, pp. 424-438.Russia, KazakhstanSubduction
DS201212-0749
2012
Vani, T.Vani, T.New dat a in the interpretation of the geology and morphology of Maddur area, Andhra Pradesh through remote sensing.Journal of the Geological Society of India, Vol. 80, 1, pp. 145-147.India, Andhra PradeshDeposit - Maddur
DS201212-0750
2012
Vani, T.Vani, T., Haga Laksmi, V., Ramakrishnarao, M.V., Kelly, G.R., Subbarao, K.V.Integration of geophsyical and geological dat a of kimberlites in Narayayanapet - Maddur field, Andhra Pradesh, India.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractIndia, Andhra PradeshDeposit - Narayayanapet-Maddur
DS201312-0936
2013
Vani, T.Vani, T., Naga Lakshmi, V.Inetgration of geophysical and geological dat a of kimberlites in Narayanpet-Maddur field, Andhra Pradesh, India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 229-239.India, Andhra PradeshDeposit - Narayanpet
DS201412-0941
2013
Vani, T.Vani, T., Lakshimi, V.N., Ramakrishnarao, M.V., Keller, G.R., Subbarao, K.V.Integration of geophysical and geological dat a of kimberlites in Narayanpet-Maddur field, Andhra Pradesh, India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 229-240.India, Andhra PradeshDeposit - Narayanpet- Maddur
DS1986-0122
1986
Vanier, M.Campiglio, C., Marion, C., Vanier, M.Study of an olivine boninite from New Caledonia- petrography and mineralchemistry.(in French)Bulletin. Mineralogie, (in French), Vol. 109, No. 4, pp. 423-440New CaledoniaBlank
DS202104-0579
2021
Vanier, M-A.Godet, A., Guilmette, C.,Labrousse, L., Smit, M.A., Cutts, J.A., Davis, D.W., Vanier, M-A.Lu-Hf garnet dating and the timing of collisions: Paleoproterozoic accretionary tectonics revealed in the southeastern Churchill Province Trans-Hudson Orogen, Canada. Torngat, New QuebecJournal of Metamorphic Geology, doi:10.1111/jmg.12599Canada, Quebeccratons

Abstract: Dating the onset of continental collision is fundamental in defining orogenic cycles and their effects on regional tectonics and geodynamic processes through time. Part of the Palaeoproterozoic Trans?Hudson Orogen, the Southeastern Churchill Province (SECP) is interpreted to result from the amalgamation of Archean to Palaeoproterozoic crustal blocks (amalgamated as the central Core Zone) that diachronically collided with the margins of the North Atlantic and Superior cratons, resulting in two bounding transpressive orogens: the Torngat and New Quebec Orogens. The SECP exposes mainly gneissic middle to lower orogenic crust in which deformation and amphibolite to granulite facies metamorphism and anatexis overprinted the early geological features classically used to constrain the timing of collisional events. To enable improved tectonic models for the development of the SECP, and the Trans?Hudson as a whole, we investigated granulite facies supracrustal sequences from the Tasiuyak Complex (TC) accretionary prism and the western margin of the North Atlantic Craton-that is, Saglek Block (upper plate)-using a multi?chronometer approach coupled with trace element geochemistry. In particular, the use of garnet Lu-Hf geochronology provides an important minimal time constraint for crustal thickening and collision. Garnet growth in the TC is constrained at 1885 ± 12 Ma (Lu-Hf), indistinguishable from U-Pb age of prograde monazite at 1873 ± 5 Ma. Zircon growth during melt crystallization occurred at 1848 ± 12 Ma. Garnet from the overriding Saglek Block is dated at 2567 ± 4.4 Ma (Lu-Hf) and indicates that gneissic rocks from the upper plate did not record the metamorphic imprint of the Torngat Orogeny. The diachronicity of the integrated metamorphic record across the strike of the SECP is explained by the location of terrane boundaries, consistent with the westward growth of the Churchill plate margin through sequential amalgamation of narrow crustal blocks during accretionary tectonics from c. 1.9 to 1.8 Ga.
DS202111-1767
2021
Vanier, M-A.Godet, A., Guilmette, C., Labrousse, L., Smit, M.A., Cutts, J.A., Davis, D.W., Vanier, M-A.Lu-Hf garnet dating and the timing of collisions: Paleoproterozoic accretionary tectonics revealed in the southeastern Churchill Province, Trans-Hudson orogen, Canada.Journal of Metamorphic Geology, Vol. 39, 8, 31p. PdfCanadageochronology

Abstract: Dating the onset of continental collision is fundamental in defining orogenic cycles and their effects on regional tectonics and geodynamic processes through time. Part of the Palaeoproterozoic Trans-Hudson Orogen, the Southeastern Churchill Province (SECP) is interpreted to result from the amalgamation of Archean to Palaeoproterozoic crustal blocks (amalgamated as the central Core Zone) that diachronically collided with the margins of the North Atlantic and Superior cratons, resulting in two bounding transpressive orogens: the Torngat and New Quebec Orogens. The SECP exposes mainly gneissic middle to lower orogenic crust in which deformation and amphibolite to granulite facies metamorphism and anatexis overprinted the early geological features classically used to constrain the timing of collisional events. To enable improved tectonic models for the development of the SECP, and the Trans-Hudson as a whole, we investigated granulite facies supracrustal sequences from the Tasiuyak Complex (TC) accretionary prism and the western margin of the North Atlantic Craton—that is, Saglek Block (upper plate)—using a multi-chronometer approach coupled with trace element geochemistry. In particular, the use of garnet Lu-Hf geochronology provides an important minimal time constraint for crustal thickening and collision. Garnet growth in the TC is constrained at 1885 ± 12 Ma (Lu-Hf), indistinguishable from U-Pb age of prograde monazite at 1873 ± 5 Ma. Zircon growth during melt crystallization occurred at 1848 ± 12 Ma. Garnet from the overriding Saglek Block is dated at 2567 ± 4.4 Ma (Lu-Hf) and indicates that gneissic rocks from the upper plate did not record the metamorphic imprint of the Torngat Orogeny. The diachronicity of the integrated metamorphic record across the strike of the SECP is explained by the location of terrane boundaries, consistent with the westward growth of the Churchill plate margin through sequential amalgamation of narrow crustal blocks during accretionary tectonics from c. 1.9 to 1.8 Ga.
DS1985-0694
1985
Vaniman, D.Vaniman, D., Laughlin, A.W., Gladney, E.S.Navajo Minettes in the Cerros de la Mujeres, New MexicoEarth Plan. Sci. Letters, Vol. 74, PP. 69-80.United States, Colorado Plateau, New MexicoMicroprobe Analyses, Geochemistry, Age Dating, Geochronology
DS1991-0057
1991
Vaniman, D.T.Baldridge, W.S., Perry, F.V., Vaniman, D.T., et al.Middle to late Cenozoic magmatism of the southeastern Colorado Plateau And central Rio Grande rift ( New Mexico and Arizona): a model for continentalriftingTectonophysics, Vol. 197, No. 2-4, November pp. 327-354New Mexico, Arizona, Colorado PlateauTectonics, Rift systems
DS201604-0637
2016
Vanity FairVanity FairThe over the hill mob. The Great Haddon Garden heist of 2015.Vanity Fair, March pp. 187-191, p. 226-229.Europe, EnglandHaddon Garden heist
DS1994-1863
1994
Vankeken, P.E.Vlaar, N.J, Vankeken, P.E., Vandenbe, A.P.Cooling of the earth in the Archean -consequences of pressure release melting in a hotter mantle.Earth and Planetary Sciences, Vol. 121, No. 1-2, January pp. 1-18.MantleMelting
DS201212-0055
2012
VanKeken, P.E.Barcheck, C.G., Wiens, D.A., VanKeken, P.E., Hacker, B.R.The relationship of intermediate and deep focus seismicity to the hydration and dehydration of subducting slabs.Earth and Planetary Science Letters, Vol. 349-350 pp. 153-160.MantleSubduction
DS2003-0062
2003
Vanko, G.Badro, J., Fiquet, G., Guyot, F., Rueff, J.P., Stuzhkin, V.V., Vanko, G., Monaco, G.Iron partitioning in Earth's mantle: toward a deep mantle discontinuityScience, Vol. 300, 5620, May 2, p. 789.MantleMineralogy
DS200412-0084
2003
Vanko, G.Badro, J., Fiquet, G., Guyot, F., Rueff, J.P., Stuzhkin, V.V., Vanko, G., Monaco, G.Iron partitioning in Earth's mantle: toward a deep mantle discontinuity.Science, Vol. 300, 5620, May 2, p. 789.MantleMineralogy
DS200412-0085
2004
Vanko, G.Badro, J., Rueff, J.P., Vanko, G., Monaco, G., Fiquet, G., Guyot, F.Electronic transitions in perovskite: possible nonconvecting layers in the lower mantle.Science, Vol. 305, No. 5682, July 16, pp. 383-385.MantleMineral chemistry
DS1994-1839
1994
Vankova, V.Vanek, J., Vankova, V., Hanus, V.Geochemical zonation of volcanic rocks and deep structure of Ecuador and southern ColombiaJournal of South American Earth Sciences, Vol. 7, No. 1, pp. 57-67GlobalGeochemistry, Tectonics, Structure
DS1985-0282
1985
Vanlerberghe, L.Hertogen, J., Vanlerberghe, L., Namegabe, M.R.Geochemical Evolution of the Nyiragongo VolcanoBulletin. Geological Society Finland, Vol. 57, pt. 1-2 pp. 21-35Democratic Republic of CongoMeliltite, Leucitite, Rift, Tectonics
DS2000-0930
2000
Vann, J.Stephenson, P.R., Vann, J.Common sense and good communication in mineral resource and ore reserve estimation.Min. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 13-20.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS202201-0045
2021
Vanneste, T.Vanneste, T.Blood, Sweat and Earth: The struggle for control over the world's diamonds through history.Reaktion Books, London UK, isbn 978-1789144352GlobalBook - notice

Abstract: Blood, Sweat and Earth is a hard-hitting historical exposé of the diamond industry, focusing on the exploitation of workers and the environment, the monopolization of uncut diamonds, and how little this has changed over time. It describes the use of forced labor and political oppression by Indian sultans, Portuguese colonizers in Brazil, and Western industrialists in many parts of Africa - as well as the hoarding of diamonds to maintain high prices, from the English East India Company to De Beers. While recent discoveries of diamond deposits in Siberia, Canada, and Australia have brought an end to monopolization, the book shows that advances in the production of synthetic diamonds have not yet been able to eradicate the exploitation caused by the world’s unquenchable thirst for sparkle.
DS200412-1664
2004
Vanni, C.Ricolleau, A., Perrillat, J.P., Fiquet, G., Menguy, N., Daniel, I., Addad, A., Vanni, C.The fate of subducted basaltic crust in the Earth's lower mantle: an experimental petrological study.Lithos, ABSTRACTS only, Vol. 73, p. S93. abstractMantleSubduction
DS1984-0150
1984
Vannier, M.Berger, E.T., Vannier, M.Petrology of Megacrysts, Mafic and Ultramafic Xenoliths From the Pipe of Eglazines, Causses France.Third Kimb Conference, Vol. 1, PP. 155-168.GlobalRelated Rocks, Chemical Analyses, Petrography
DS200412-0336
2004
Vannucchi, P.Clift, P., Vannucchi, P.Controls on tectonic accretion versus erosion in subduction zones: implications for the origin and recycling of the continentalReviews of Geophysics, Vol. 42, 2, 10.1029/2003 RG000127MantleSubduction
DS200412-0337
2004
Vannucchi, P.Clift, P., Vannucchi, P.Controls on tectonic accretion versus erosion in subduction zones: implications for the origin and recycling of the continentalReviews of Geophysics, Vol. 42, 2, April 8, 10.1029/2003 RG000127MantleSubduction
DS200912-0116
2009
Vannucchi, P.Clift, P.D., Schouten, H., Vannucchi, P.Arc continent collisions, sediment recycling and the maintenance of the continental crust.Geological Society of London, Special Publication Earth Accretionary systems in Space and Time, No. 318, pp. 75-103.MantleTectonics
DS202101-0037
2020
Vannucchi, P.Vannucchi, P., Morgan, J.P., Polonia, A., Molli, G.The life cycle of subcontinental peridotites: from rifted continental margins to mountains via subduction processes.Geology, Vol. 48, pp. 1154-1158. pdfMantlesubduction

Abstract: Serpentinization greatly affects the physical and chemical properties of lithospheric mantle. Here we address the fate of serpentinized peridotites and their influence over an entire Wilson cycle. We document the near-surface journey of serpentinized subcontinental peridotites exhumed during rifting and continental breakup, reactivated as buoyant material during subduction, and ultimately emplaced as "ophiolite-like" fragments within orogenic belts. This life cycle is particularly well documented in former Tethys margins, where recent studies describe the ongoing incorporation of Mesozoic serpentinized subcontinental peridotites that diapirically rise from a subducting lower plate’s mantle to be emplaced into the accretionary prism in front of a continental arc. This newly recognized mode of subduction-linked serpentine diapirism from the downgoing lithospheric slab is consistent with the origin of some exhumed serpentinized subcontinental peridotites in the Apennines (Italy), these assemblages reaching their present locations during Alpine orogenesis. Transfer of serpentinized subcontinental peridotites from the downgoing to the overriding plate motivates the concept of a potentially "leaky" subduction channel. Weak serpentine bodies may in fact rise into, preferentially migrate within, and eventually leave the intraplate shear zone, leading to strong lateral heterogeneities in its composition and mechanical strength.
DS2001-1023
2001
VannucciScambelluri, M., Bottazzi, P., Trommsdorff, VannucciIncompatible element rich fluids released by antigorite breakdown in deeply subducted mantle.Earth and Planetary Science Letters, Vol. 192, No. 3, pp. 457-70.MantleGeochemistry, Subduction
DS1992-1015
1992
Vannucci, R.Mazzucchelli, M., Rivalenti, G., Vannucci, R., Bottazzi, P.Trace element distribution between clinopyroxene and garnet in gabbroicGeochimica et Cosmochimica Acta, Vol. 56, pp. 2371-2385ItalyCrust, Mafic-ultramafic, Garnet, clinopyroxene
DS1993-1650
1993
Vannucci, R.Vannucci, R., Shimizu, N., Piccado, G.B., Ottolini, L., Bottazzi, P.Distribution of trace elements during breakdown of mantle garnet: an example from Zabargad.Contribution to Mineralogy and Petrology, Vol. 113, pp. 437-449.GlobalMantle, Garnet geochronology
DS1994-1840
1994
Vannucci, R.Vannucci, R., Bottazzi, P., et al.The trace element variations in clinopyroxenes from spinel peridotite xenoliths from southwest Poland.Mineralogical Magazine, Vol. 58A, pp. 932-933. AbstractAustraliaXenoliths, Geochemistry
DS1995-2154
1995
Vannucci, R.Zinngrebe, E., Foley, S.F., Vannucci, R., Bottazi, MatteyMetasomatism of peridotite by alkaline melt and cognate fluid:microchemical and ion probe evidence from low pressureProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 700-702.Russia, Yakutia, Aldan ShieldMetasomatism, Deposit -Inagli complex
DS1996-1192
1996
Vannucci, R.Rivalenti, G., Vannucci, R., Ottolinim L.Peridotite clinopyroxene chemistry reflects mantle processes rather continental versus oceanic settingEarth And Planetary Science Letters, Vol. 139, No. 3-4, April 1, pp. 423-438.MantleGeochemistry, Peridotite
DS1998-0954
1998
Vannucci, R.Mason, P.R.D., Downes, H., Jarvis, K., Vannucci, R.An investigation of incompatible trace elements in Massif Central mantle xenoliths by laser ablation.7th International Kimberlite Conference Abstract, pp. 549-1MantleGeochemistry - ICP-MS, Xenoliths -light rare earth element (LREE).
DS2003-1380
2003
Vannucci, R.Tiepolo, M., Zanetti, A., Oberti, R., Brumm, R., Foley, S., Vannucci, R.Trace element partitioning between synthetic potassic richterites and silicate melts, andEuropean Journal of Mineralogy, Vol. 15, 2, pp. 329-40.GlobalMineralogy
DS200412-0563
2004
Vannucci, R.Foley, S., Vannucci, R., Jacob, D., Tiepolo, M.The geochemical signature and origin of Archean TTG gneisses: melting of amphibolite or eclogite?Lithos, ABSTRACTS only, Vol. 73, p. S38. abstractTechnologySubduction
DS200412-1478
2004
Vannucci, R.O'Reilly, S.Y., Vannucci, R.Trace element fingerprinting: laboratory studies and petrogenetic processes.Lithos, Vol. 75, 1-2, July pp. ix-xiTechnologyMetasomatism, trace element fingerprinting, petrogeneti
DS200412-1992
2003
Vannucci, R.Tiepolo, M., Zanetti, A., Oberti, R., Brumm, R., Foley, S., Vannucci, R.Trace element partitioning between synthetic potassic richterites and silicate melts, and contrasts with the partitioning behaviEuropean Journal of Mineralogy, Vol. 15, 2, pp. 329-40.TechnologyMineralogy
DS200412-2197
2004
Vannucci, R.Zanetti, A., Tiepolo, M., Oberti, R., Vannucci, R.Trace element partitioning in olivine: modelling of a complete dat a set from a synthetic hydrous basanite melt.Lithos, Vol. 75, 1-2, July, pp. 39-54.TechnologyGeochemistry - petrogenetic processes, fingerprinting
DS200512-0804
2004
Vannucci, R.Ohtani, L., Le Fevre, B., Vannucci, R.Direct assessment of mantle boron and lithium contents and distribution by SIMS analyses of peridotite minerals.Earth and Planetary Science Letters, Vol. 228, 1-2, Nov. 30, pp. 19-36.MantlePeridotite, pyrolitic mantle
DS200512-0907
2004
Vannucci, R.Rivalenti, G., Mazzucchelli, M., Laurora, A., Ciuffi, S.I.A., Zanetti, A., Vannucci, R., Cingolani, C.A.The backarc mantle lithosphere in Patagonia, South America.Journal of South American Earth Sciences, Vol. 17, 2, Oct. 30, pp. 121-152.South America, PatagoniaXenoliths, geothermometry, melting, slab, subduction
DS200912-0607
2009
Vannucci, R.Raffone, N., Chazot, G., Pin, C., Vannucci, R., Zanetti, A.Metasomatism in the lithospheric mantle beneath Middle Atlas ( Morocco) and the origin of Fe- and Mg- rich wehrlites.Journal of Petrology, Vol. 50, 2, pp. 197-249.Africa, MoroccoMetasomatism
DS201509-0396
2015
Vannucci, R.France, L., Chazot, G., Kornprobst, J., Dallai, L., Vannucci, R., Gregoire, M., Bertrand, H., Boivin, P.Mantle refertilization and magmatism in old orogenic regions: the role of late-orogenic pyroxenites.Lithos, Vol. 232, pp. 49-75.Africa, Morocco, Cameroon, Jordan, Europe, FranceXenoliths

Abstract: Pyroxenites and garnet pyroxenites are mantle heterogeneities characterized by a lower solidus temperature than the enclosing peridotites; it follows that they are preferentially involved during magma genesis. Constraining their origin, composition, and the interactions they underwent during their subsequent evolution is therefore essential to discuss the sources of magmatism in a given area. Pyroxenites could represent either recycling of crustal rocks in mantle domains or mantle originated rocks (formed either by olivine consuming melt-rock reactions or by crystal fractionation). Petrological and geochemical (major and trace elements, Sr-Nd and O isotopes) features of xenoliths from various occurrences (French Massif-Central, Jordan, Morocco and Cameroon) show that these samples represent cumulates crystallized during melt percolation at mantle conditions. They formed in mantle domains at pressures of 1-2 GPa during post-collisional magmatism (possibly Hercynian for the French Massif-Central, and Panafrican for Morocco, Jordan and Cameroon). The thermal re-equilibration of lithospheric domains, typical of the late orogenic exhumation stages, is also recorded by the samples. Most of the samples display a metasomatic overprint that may be either inherited or likely linked to the recent volcanic activity that occurred in the investigated regions. The crystallization of pyroxenites during late orogenic events has implications for the subsequent evolution of the mantle domains. The presence of large amounts of mantle pyroxenites in old orogenic regions indeed imparts peculiar physical and chemical characteristics to these domains. Among others, the global solidus temperature of the whole lithospheric domain will be lowered; in turn, this implies that old orogenic regions are refertilized zones where magmatic activity would be enhanced.
DS1990-1504
1990
Vanoort, E.Vanoort, E., Stroomer, P., Glasbeek, M.Low-field optically detected magnetic -resonance of a coupled triplet-doublet defect pair in diamondPhys. Rev. B., Vol. 42, No. 13, Nov. 1, pp. 8605-8608GlobalDiamond morphology, Experimental petrology
DS201112-0285
2010
Van-Orman, J.Dosseto, A., Turner, S., Van-Orman, J.Timescales of magmatic processes: from core to atmosphere.Wiley Blackwell, Paperback 978-1-444-33261-2 $ 100.00GlobalBook - advertisement
DS201904-0791
2019
Vanpoucke, D.E.P.Vanpoucke, D.E.P., Nicely, S.S., Raymakers, J., Maes, W., Haenen, K.Can europium atoms form luminescent centres in diamond: a combined theoretical-experimental study.Diamond and Related Materials, https://doi.org/j. diamond.2019.02.024Globaldiamond morphology

Abstract: The incorporation of Eu into the diamond lattice is investigated in a combined theoretical-experimental study. The large size of the Eu ion induces a strain on the host lattice, which is minimal for the Eu-vacancy complex. The oxidation state of Eu is calculated to be 3+ for all defect models considered. In contrast, the total charge of the defect-complexes is shown to be negative: ?1.5 to ?2.3 electron. Hybrid-functional electronic-band-structures show the luminescence of the Eu defect to be strongly dependent on the local defect geometry. The 4-coordinated Eu substitutional dopant is the most promising candidate to present the typical Eu3+ luminescence, while the 6-coordinated Eu-vacancy complex is expected not to present any luminescent behaviour. Preliminary experimental results on the treatment of diamond films with Eu-containing precursor indicate the possible incorporation of Eu into diamond films treated by drop-casting. Changes in the PL spectrum, with the main luminescent peak shifting from approximately 614?nm to 611?nm after the growth plasma exposure, and the appearance of a shoulder peak at 625?nm indicate the potential incorporation. Drop-casting treatment with an electronegative polymer material was shown not to be necessary to observe the Eu signature following the plasma exposure, and increased the background luminescence.
DS201905-1083
2019
Vanpoucke, D.E.P.Vanpoucke, D.E.P., Nicley, S.S., Raymakers, J., Maes, W., Haenen, K.Can europium atoms form luminescent centres in diamond: a combined theoretical-experimental study.Diamond & Related Materials, Vol. 94, pp. 233-241.Globalluminescence

Abstract: The incorporation of Eu into the diamond lattice is investigated in a combined theoretical-experimental study. The large size of the Eu ion induces a strain on the host lattice, which is minimal for the Eu-vacancy complex. The oxidation state of Eu is calculated to be 3+ for all defect models considered. In contrast, the total charge of the defect-complexes is shown to be negative: ?1.5 to ?2.3 electron. Hybrid-functional electronic-band-structures show the luminescence of the Eu defect to be strongly dependent on the local defect geometry. The 4-coordinated Eu substitutional dopant is the most promising candidate to present the typical Eu3+ luminescence, while the 6-coordinated Eu-vacancy complex is expected not to present any luminescent behaviour. Preliminary experimental results on the treatment of diamond films with Eu-containing precursor indicate the possible incorporation of Eu into diamond films treated by drop-casting. Changes in the PL spectrum, with the main luminescent peak shifting from approximately 614?nm to 611?nm after the growth plasma exposure, and the appearance of a shoulder peak at 625?nm indicate the potential incorporation. Drop-casting treatment with an electronegative polymer material was shown not to be necessary to observe the Eu signature following the plasma exposure, and increased the background luminescence.
DS202205-0674
2022
Vanpoucke, D.E.P.Boldyrev, K.N., Sedov, V.S., Vanpoucke, D.E.P., Ralchenko, V.G., Mavrin, B.N.Photoluminescence and first principles phonon study.Diamond and Related Materials, Vol. 126, 6p. PdfGlobalLuminescence
DS1989-1088
1989
Vanrijn, H.J.Nam, T.L., Fallon, P.J., Keddy, R.J., Vanrijn, H.J.Detection of nuclear radiation by scintillation-counting using syntheticdiamondAppl. Rad. Is, Vol. 40, No. 8, pp. 657-661GlobalDiamond synthesis
DS200612-1469
2005
VanSummeren, J.Van Thielen, P., VanSummeren, J., VanderHilst, R.D., VandenBerg, A.P., Vlaar, N.J.Numerical study of the origin and stability of chemically distinct reservoirs deep in the Earth's mantle.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 117-136.MantleGeochemistry
DS201910-2249
2019
Vantelon, D.Chasse, M., Blanchard, M., Cabareta, D., Juhin, A., Vantelon, D., Griffin, W.L., O'Reilly, S.Y., Calas, G.Deciphering molecular-scale mechanisms covering scandium dynamics in the critical zone. Goldschmidt2019, in press available, 71 ppt.Australialaterites

Abstract: Scandium is often considered as immobile during chemical weathering, based on its low solubility. In contrast to other conservative (i.e. relatively immobile) elements incorporated into accessory minerals resistant to weathering (e.g. zirconium, thorium or niobium), the scarcity of scandium minerals indicates that the processes accounting for scandium's immobilisation are distinctive. However, the evolution of scandium speciation during weathering is unknown, limiting the understanding of the processes controlling its dynamics in the critical zone. Exceptional scandium concentrations in east Australian laterites provide the possibility of unravelling these mechanisms. We follow scandium speciation through thick lateritic profiles (> 30 m) using a multiscale mineralogical and spectroscopic approach involving electron microprobe, laser-ablation--inductively coupled plasma mass spectrometry, selective leaching and X-ray absorption near-edge structure spectroscopy, complemented by mass-transfer calculations. We show that the initial reservoir of scandium contained in the parent rock is preserved under reducing conditions occurring in the lowest horizons of the profiles. The dissolution of scandium-bearing clinopyroxene generates smectitic clays that immobilise and concentrate scandium. It is subsequently trapped in the lateritic duricrust by goethite. Scandium mobilisation appears in this horizon and increases upward as a result of the dissolution of goethite, possibly assisted by dissolved organic matter, and the precipitation of hematite. Molecular-scale analyses demonstrate that changes in speciation govern scandium dynamics, with substitution in smectitic clays and adsorption on iron oxyhydroxides playing a crucial role in scandium immobility in the saprolite and lower lateritic duricrust. The higher affinity of scandium for goethite relative to hematite drives scandium mobilisation in the upper lateritic duricrust, leading to its concentration downward in the lower lateritic duricrust. These successive mechanisms illustrate how the unique complexity of the critical zone leads to scandium concentrations that may form new types of world-class scandium deposits. Comparison with conservative elements and with rare-earth elements, expected to have similar geochemical properties, emphasizes the unique behaviour of scandium in the critical zone. While scandium remains immobile during the early stages of weathering, intense and long-term alteration processes, observed in lateritic contexts, lead to scandium mobilisation. This study highlights the dependence of scandium mobility on weathering conditions.
DS202004-0503
2020
Vantelon, D.Chasse, M., Blanchard, M., Cabaret, D., Vantelon, D., Juan, A., Calas, G.First principles modeling of X-ray absorption spectra enlightens the process of scandium sequestration by iron oxides.American Mineralogist, Vol. 105, 7, 10.2138/am-2020-730Globalscandium

Abstract: Scandium is often associated with iron oxides in the environment. Despite the use of scandium as a geochemical tracer and the existence of world-class supergene deposits, uncertainties on speciation obscure the processes governing its sequestration and concentration. Here, we use first-principles approaches to interpret experimental K-edge X-ray absorption near-edge structure spectra of scandium either incorporated in or adsorbed on goethite and hematite, at concentrations relevant for the environment. This modeling helps to interpret the characteristic spectral features, providing key information to determine scandium speciation when associated with iron oxides. We show that scandium is substituted into iron oxides at low concentration without modifying the crystal structure. When scandium is adsorbed onto iron oxide surfaces, the process occurs through outer-sphere complexation with a reduction in the coordination number of the hydration shell. Considering available X-ray absorption spectra from laterites, the present results confirm that scandium adsorption onto iron oxides is the dominant mechanism of sequestration in these geochemical conditions. This speciation explains efficient scandium recovery through mild metallurgical treatments of supergene lateritic ores. The specificities of scandium sorption mechanisms are related to the preservation of adsorbed scandium in million-years old laterites. These results demonstrate the emerging ability to precisely model fine X-ray absorption spectral features of trace metals associated with mineral phases relevant to the environment. It opens new perspectives to accurately determine trace metals speciation from high-resolution spatially-resolved X-ray absorption near-edge structure spectroscopy in order to constrain the molecular mechanisms controlling their dynamics.
DS1989-1541
1989
Vanthiel, M.Vanthiel, M., rare earth elements (REE), F.H.Theoretical description of the graphite, diamond and liquid phases ofcarbonInternational Journal of TherM., Vol. 10, No. 1, January pp. 227-236GlobalExperimental petrology, Carbon
DS201706-1090
2017
VanTongeren, J.Levin, V., Servali, A., VanTongeren, J., Menke, W., Darbyshire, F.Crust-mantle boundary in eastern North America, from the (oldest) craton to the (youngest) rift.Geological Society of America, SPE 526 pp. 107-132.United Statescraton

Abstract: The North American continent consists of a set of Archean cratons, Proterozoic orogenic belts, and a sequence of Phanerozoic accreted terranes. We present an ~1250-km-long seismological profile that crosses the Superior craton, Grenville Province, and Appalachian domains, with the goal of documenting the thickness, internal properties, and the nature of the lower boundary of the North American crust using uniform procedures for data selection, preparation, and analysis to ensure compatibility of the constraints we derive. Crustal properties show systematic differences between the three major tectonic domains. The Archean Superior Province is characterized by thin crust, sharp Moho, and low values of Vp/Vs ratio. The Proterozoic Grenville Province has some crustal thickness variation, near-uniform values of Vp/Vs, and consistently small values of Moho thickness. Of the three tectonic domains in the region, the Grenville Province has the thickest crust. Vp/Vs ratios are systematically higher than in the Superior Province. Within the Paleozoic Appalachian orogen, all parameters (crustal thickness, Moho thickness, Vp/Vs ratio) vary broadly over distances of 100 km or less, both across the strike and along it. Internal tectonic boundaries of the Appalachians do not appear to have clear signatures in crustal properties. Of the three major tectonic boundaries crossed by our transect, two have clear manifestations in the crustal structure. The Grenville front is associated with a change in crustal thickness and crustal composition (as reflected in Vp/Vs ratios). The Norumbega fault zone is at the apex of the regional thinning of the Appalachian crust. The Appalachian front is not associated with a major change in crustal properties; rather, it coincides with a zone of complex structure resulting from prior tectonic episodes, and thus presents a clear example of tectonic inheritance over successive Wilson cycles.
DS201708-1575
2017
VanTongeren, J.Levin, V., Servali, A., VanTongeren, J., Menke, W., Darbyshire, F.Crust mantle boundary in eastern North America, from the (oldest) craton to the (youngest) rift.Geological Society of London, Chapter 6, pp. 107-132.United States, Canadatectonics

Abstract: The North American continent consists of a set of Archean cratons, Proterozoic orogenic belts, and a Sequence of Phanerozoic accreted terranes. We present an ~1250-km-long seismological profile that crosses the Superior craton, Grenville Province, and Appalachian domains, with the goal of documenting the thickness, internal properties, and the nature of the lower boundary of the North American crust using uniform procedures for data selection, preparation, and analysis to ensure compatibility of the constraints we derive. Crustal properties show systematic differences between the three major tectonic domains. The Archean Superior Province is characterized by thin crust, sharp Moho, and low values of Vp/Vs ratio. The Proterozoic Grenville Province has some crustal thickness variation, near-uniform values of Vp/Vs, and consistently small values of Moho thickness. Of the three tectonic domains in the region, the Grenville Province has the thickest crust. Vp/Vs ratios are systematically higher than in the Superior Province. Within the Paleozoic Appalachian orogen, all parameters (crustal thickness, Moho thickness, Vp/Vs ratio) vary broadly over distances of 100 km or less, both across the strike and along it. Internal tectonic boundaries of the Appalachians do not appear to have clear signatures in crustal properties. Of the three major tectonic boundaries crossed by our transect, two have clear manifestations in the crustal structure. The Grenville front is associated with a change in crustal thickness and crustal composition (as reflected in Vp/Vs ratios). The Norumbega fault zone is at the apex of the regional thinning of the Appalachian crust. The Appalachian front is not associated with a major change in crustal properties; rather, it coincides with a zone of complex structure resulting from prior tectonic episodes, and thus presents a clear example of tectonic inheritance over successive Wilson cycles.
DS201412-0433
2013
VanTongeren, J.A.Johnson, T.E., Brown, M., Klaus, J.P., VanTongeren, J.A.Delamination and recycling of Archean crust caused by gravitational instabilities.Nature Geoscience, Vol. 7, 1p.MantleArchean - craton
DS1950-0435
1958
Vantyne, A.M.Vantyne, A.M.Petrology of the Euclid Avenue Peridotite IntrusivesMsc. Thesis, Syracuse University, 144P.United States, Appalachia, New YorkPetrology
DS2001-1022
2001
VanucciScambelluri, M., Bottazzi, P., Trommsdorf, V., VanucciThe analysis of fluid + mineral inclusions in deeply subducted hydrous mantle: implications for genesis...Plinius, No. 24, p. 193-4 abstractMantleTrace element rich supercritical fluids, Subduction
DS1999-0823
1999
Vanucci, R.Zanetti, A., Mazzucchelli, M., Vanucci, R.The Finero phlogopite peridotite massif: an example of subduction relatedMetasomatismContributions to Mineralogy and Petrology, Vol. 134, No. 2-3, pp. 107-122.ItalyMetasomatism, perioditite
DS2001-1291
2001
Vanucci, R.Zanetti, A., Vanucci, R., Piccardo, G.B.The lithospheric mantle beneath the Assab region: a LAM ICP Ms study of peridotite and pyroxenite xenoliths.Plinius, No. 24, pp. 223-4. abstractGlobalXenoliths, Afur region - eastern African Rift
DS200412-1674
2004
Vanucci, R.Rivalenti, G., Zanetti, A., Mazzucchelli, M., Vanucci, R., Congolani, C.A.Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case ( Santa Cruz ProvinContributions to Mineralogy and Petrology, Vol. 147, 6, pp. 647-670.South America, ArgentinaCarbonatite
DS200412-1738
2004
Vanucci, R.Scambelluri, M., Muntener, O., Ottolini, L., Pettke, T.T., Vanucci, R.The fate of B, Cl and Li in the subducted oceanic mantle and in the antigorite breakdown fluids.Earth and Planetary Science Letters, Vol. 222, 1, pp. 217-234.MantleSubduction, geochemistry
DS1859-0061
1837
Vanuxem, L.Vanuxem, L.Mafic Dike at East Canada Creek New York StateSecond Annual Report Geological Survey Third District New York, P. 265.United States, Appalachia, New YorkGeology
DS1859-0068
1839
Vanuxem, L.Vanuxem, L.Geological Survey of New York, Dikes in SyracuseThird Annual Report Geological Survey Third District New York, P. 160; 256; 260; 283.United States, Appalachia, New YorkGeology
DS1859-0077
1842
Vanuxem, L.Vanuxem, L.Natural History of New York. Geological Survey of New York, igneous Dikes at Syracuse, Ludlowville and Manheim.Final Report Geological Survey Third District New York, PT. 3, PP. 109-110; P. 169; PP. 207-208.United States, Appalachia, New YorkGeology
DS201605-0822
2016
vanWijk, J.Currie, C.A., vanWijk, J.How craton margins are preserved: insights into geodynamic models.Journal of Geodynamics, in press available 48p.CanadaNorth American craton
DS1990-1580
1990
Vanwyk, J.A.Woods, G.S., Vanwyk, J.A., Collins, A.T.The nitrogen content of type 1B synthetic diamondPhil. Magazine B., Vol. 62, No. 6, December pp. 589-595GlobalDiamond synthesis, Nitrogen
DS1994-0799
1994
Vanyan, L.L.Hyndman, R.D., Vanyan, L.L., Marquis, G., Law, L.K.The origin of electrically conductive lower continental crust: saline wateror graphite?Physics of the Earth and Planetary Interiors, Vol. 81, pp. 325-344.MantleGeophysics -magnetotellurics, Graphite, carbon
DS200412-2044
2004
Vanyo, J.P.Vanyo, J.P.Core mantle relative motion and coupling.Geophysical Journal International, Vol. 158, 2, pp. 470-478.MantleTectonics
DS200712-0931
2007
Vapnik, Y.Samoilov, V.S., Vapnik, Y.Fractional melting the determining factor in the origin of the tephrite basanite nephelinite rock some evidence from western Makhtesh Ramon, Israel.Neues Jahrbuch fur Mineralogie, Vol. 184, 2, pp. 181-195.Europe, IsraelBasanites, Foidites
DS200812-0997
2007
Vapnik, Y.Samoilov, V.S., Vapnik, Y.Fractional melting the determining factor in the origin of the tephrite basanite nephelinite rock suite: evidence from western Makhtesh Ramon, Israel.Neues Jahrbuch fur Mineralogie, Vol. 184, 2, pp. 181-195.Europe, IsraelBasanites, Foidites
DS200812-1047
2007
Vapnik, Y.Sharygin, V.V., Szabo, C., Kothay, K., Timina, T.Ju., Peto, MN., Torok, K., Vapnik, Y., Kuzmin, D.V.Rhonite in silica undersaturated alkali basalts: inferences on silicate melt inclusions in olivine phenocrysts.Vladykin Volume 2007, pp. 157-182.RussiaPetrology
DS201312-0114
2013
Varadan, R.Burtseva, M.V., Ripp, G.S., Doroshkevich, A.G., Viladkar, S.G., Varadan, R.Features of mineral and chemical composition of the Khamambettu carbonatites, Tamil, Nadu.Journal of the Geological Society of India, Vol. 81, 5, pp. 655-664.IndiaCarbonatite
DS1859-0001
1500
VarahamiraVarahamiraBrhatsamhitaUnknown, IndiaDiamond Occurrence
DS201412-0038
2014
Varajao, A.F.D.C.Barreto, H.N., Varajao, C.A.C., Braucher, R., Bourles, D.L., Salgado, A.A.R, Varajao, A.F.D.C.The impact of diamond extraction on natural denudation rates in the Diamantin a Plateau ( Min as Gerais, Brazil).Journal of South American Earth Sciences, Vol 56, pp. 357-364.South America, BrazilMining
DS201412-0038
2014
Varajao, C.A.C.Barreto, H.N., Varajao, C.A.C., Braucher, R., Bourles, D.L., Salgado, A.A.R, Varajao, A.F.D.C.The impact of diamond extraction on natural denudation rates in the Diamantin a Plateau ( Min as Gerais, Brazil).Journal of South American Earth Sciences, Vol 56, pp. 357-364.South America, BrazilMining
DS1960-0755
1966
Varashavsky, A.V.Varashavsky, A.V.Some Aspects of the Anomalous Birefringence and Intrinsic Morphology of Diamonds.Doklady Academy of Science USSR, Earth Science Section., Vol. 166, No. 1-6, PP. 113-116.RussiaCrystallography, Mir, Aykhal
DS201704-0650
2016
Varas-Reu, M.I.Varas-Reu, M.I., Garrido, C.J., Marchesi, C., Bodinier, J-L., Frets, E., Bosch, D., Tommasi, A., Hidas, K., Targuisti, K.Refertilization processes of the subcontinental lithospheric mantle: the record of the Beni Bousera orogenic peridotite ( Rif Belt, northern Morocco).Journal of Petrology, Vol. 57, 11-12, pp. 2251-2270.Africa, MoroccoDeposit - Beni Bousera

Abstract: Correlations between major and minor transition elements in tectonically emplaced orogenic peridotites have been ascribed to variable degrees of melt extraction and melt-rock reaction processes, leading to depletion or refertilization. To elucidate how such processes are recorded in the subcontinental lithospheric mantle, we processed a large geochemical dataset for peridotites from the four tectono-metamorphic domains of the Beni Bousera orogenic massif (Rif Belt, northern Morocco). Our study reveals that variations in bulk-rock major and minor elements, Mg-number and modal mineralogy of lherzolites, as well as their clinopyroxene trace element compositions, are inconsistent with simple partial melting and mainly resulted from different reactions between melts and depleted peridotites. Up to 30% melting at <3 GPa and cryptic metasomatism can account for the geochemical variations of most harzburgites. In Grt-Sp mylonites, melting and melt-rock reactions are masked by tectonic mixing with garnet pyroxenites and subsolidus re-equilibration. In the rest of the massif, lherzolites were mostly produced by refertilization of a refractory protolith (Mg-number = 91, Ol = 70%, Cpx/Opx = 0.4) via two distinct near-solidus, melt- rock reactions: (1) clinopyroxene and orthopyroxene precipitation and olivine consumption at melt/rock ratios <0.75 and variable mass ratio between crystallized minerals and infiltrated melt ®, which are recorded fairly homogeneously throughout the massif; (2) dissolution of orthopyroxene and precipitation of clinopyroxene and olivine at melt/rock ratios <1 and R = 0.2-0.3, which affected mainly the Arie` gite-Seiland and Seiland domains. The distribution of secondary lherzolites in the massif suggests that the first refertilization reaction occurred prior to the differentiation of the Beni Bousera mantle section into petro-structural zones, whereas the second reaction was associated with the development of the tectono-metamorphic domains. Our data support a secondary, refertilization-related origin for most lherzolites in orogenic peridotite massifs.
DS201808-1794
2018
Varas-Reu, M.I.Varas-Reu, M.I., Garrido, C.J., Marchesi, C., Bosch, D., Hidas, K.Genesis of ultra high pressure garnet pyroxenites in orogenic peridotites and its bearing on the compositional heterogeneity of the Earth's mantle.Geochimica et Cosmochimica Acta, Vol. 232, pp. 303-328.Mantledeposit - Ronda, Beni Bousera

Abstract: We present an integrated geochemical study of ultra-high pressure (UHP) garnet pyroxenites from the Ronda and Beni Bousera peridotite massifs (Betic-Rif Belt, westernmost Mediterranean). Based on their Sr-Nd-Pb-Hf isotopic systematics, we classify UHP garnet pyroxenites into three groups: Group A pyroxenites (Al2O3: 15-17.5?wt.%) have low initial 87Sr/86Sr, relatively high ?Nd, ?Hf and 206Pb/204Pb ratios, and variable 207Pb/204Pb and 208Pb/204Pb. Group B pyroxenites (Al2O3?
DS201806-1258
2018
Varas-Reus, M.I.Varas-Reus, M.I., Garrido, C.J., Marchesi, C., Bosch, D., Hidas, K.Genesis of ultra-high pressure garnet pyroxenites in orogenic peridotites and its bearing on the compositional heterogeneity of the Earth's mantle. Ronda, Beni BouseraGeochimica et Cosmochimica Acta, Vol. 232, pp. 303-328.Africa, Morocco, Europe, SpainUHP

Abstract: We present an integrated geochemical study of ultra-high pressure (UHP) garnet pyroxenites from the Ronda and Beni Bousera peridotite massifs (Betic-Rif Belt, westernmost Mediterranean). Based on their Sr-Nd-Pb-Hf isotopic systematics, we classify UHP garnet pyroxenites into three groups: Group A pyroxenites (Al 2 O 3 : 15-17.5 wt. %) have low initial 87 Sr/ 86 Sr, relatively high ? Nd , ? Hf and 206 Pb/ 204 Pb ratios, and variable 207 Pb/ 204 Pb and 208 Pb/ 204 Pb. Group B pyroxenites (Al 2 O 3 < 14 wt. %) are characterized by high initial 87 Sr/ 86 Sr and relatively low ? Nd , ? Hf and 206 Pb/ 204 Pb ratios. Group C pyroxenites (Al 2 O 3 ~ 15 wt. %) have depleted radiogenic signatures with relatively low initial 87 Sr/ 86 Sr and 206 Pb/ 204 Pb, high ? Nd and ? Hf , and their 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios are similar to those of Group B pyroxenites. The major and trace element and isotopic compositions of UHP garnet pyroxenites support their derivation from ancient (1.5-3.5 Ga) oceanic crust recycled into the mantle and intimately stirred with peridotites by convection. However, the genesis of these pyroxenites requires also the involvement of recycled continental lower crust with an isotopic composition akin to the lower crustal section of the lithosphere where these UHP garnet pyroxenites now reside in. These oceanic and continental crustal components were stirred in different proportions in the convective mantle, originating pyroxenites with a more marked geochemical imprint of either oceanic (Group A) or continental lower crust (Group B), or hybrid compositions (Group C). The pyroxenite protoliths likely underwent several melting events, one of them related to the formation of the subcontinental lithospheric mantle and continental crust, generating restitic UHP garnet pyroxenites now preserved in the Ronda and Beni Bousera orogenic peridotites. The extent of melting was mostly 3 controlled by the bulk Mg-number (Mg#) of the pyroxenite protoliths, where protoliths with low Mg# experienced higher degrees of partial melting than sources with higher Mg#. Positive Eu and Sr anomalies in bulk rocks, indicative of their origin from cumulitic crustal gabbros, are preserved mostly in high Mg# pyroxenites due to their higher melting temperatures and consequent lower partial melting degrees. The results of this study show that the genesis of UHP garnet pyroxenites in orogenic peridotites requires a new recipe for the marble cake mantle hypothesis, combining significant recycling and stirring of both oceanic and continental lower crust in the Earth's mantle. Furthermore, this study establishes a firm connection between the isotopic signatures of UHP pyroxenite heterogeneities in the mantle and the continental lower crust.
DS1986-0414
1986
Varekamp, J.C.Kalamarides, R.L., Varekamp, J.C.Leucite tephrites from Latera Italy: three dimensional hybridsEos, Vol. 67, No. 44, Nov. 4, p. 1281. (abstract.)ItalyBlank
DS1992-1598
1992
Varekamp, J.C.Varekamp, J.C., Kreulen, R., Poorter, R.P.E., Van bergen, M.J.Carbon sources in arc volcanism, with implications for the carbon cycleTerra Nova, Vol. 4, pp. 363-373GlobalArc volcanism., Carbon cycle
DS1998-1521
1998
Varekamp, J.C.Varekamp, J.C., Thomas, E.Climate change and the rise and fall of sea level over the MillenniuMEos, Vol. 79, No. 6, Feb. 10, p. 69, 74-5GlobalSea level, Climate change
DS1994-1841
1994
Varela, M.E.Varela, M.E.Silicate melt and fluid inclusions in rhyolitic dykes, Los Manantiales mining district, ArgentinaEuropean Journal of Mineralogy, Vol.1994 No. 6, pp. 837-854ArgentinaMineralogy -dykes, Los Manantiales mining district
DS1997-1199
1997
Varela, M.E.Varela, M.E., Bjerg, E.A., Kurat, G.Fluid inclusions in upper mantle xenoliths from Northern Patagonia:evidence for an upper mantle diapirMineralogy and Petrology, Vol. 60, No. 3-4, pp.145-164.ArgentinaMantle, Xenoliths
DS1998-1522
1998
Varela, M.E.Varela, M.E., Clochhiatti, R., Massare, D., Schiano, P.Metasomatism in subcontinental mantle beneath Northern Pategonia: evidence from silica rich melt inclusionsMin. Petrol, Vol. 62, No. 1-2, pp. 103-122ArgentinaMetasomatism, Magmatism
DS1999-0766
1999
Varela, M.E.Varela, M.E., Clocchiatti, R., Schiano, P.Silicic glasses in hydrous and anhydrous mantle xenoliths from western Victoria - two different sourcesChemical Geology, Vol. 153, No. 1-4, Jan. pp.151-70.AustraliaXenoliths
DS2000-0973
2000
Varela, M.E.Varela, M.E., Metrich, N.Carbon in olivines and chondritic meteoritesGeochimica et Cosmochimica Acta, Vol. 64, No. 19, Oct. 1, pp. 3433-GlobalMeteorites, Carbon - geochemistry
DS201312-0620
2013
Varela, M.E.Munayco, P., Munayco, J., Varela, M.E., Scorzelli, R.B.The new Peruvian meteorite Carcancas: mossbauer spectroscopy and x-ray diffraction studies.Earth Moon Planets, Vol. 110, pp. 1-9.South America, PeruMeteorite
DS1992-0322
1992
Varela, R.Daala Salda, L., Cingolani, C., Varela, R.Early Paleozoic orogenic belt of the Andes in southwestern South America:results of Laurentia-Gondwana collision?Geology, Vol. 20, No. 7, July pp. 617-620South AmericaTectonics, Plate tectonics
DS1992-0327
1992
Varela, R.Dalla Salda, L.H., Dalziel, I.W.D., Cingolani, C.A., Varela, R.Did the Taconic Appalachians continue into southern South America?Geology, Vol. 20, No. 12, December pp. 1059-1062Appalachia, South America, ArgentinaTectonics, Orogeny
DS200812-1093
2007
Varentsov, I.M.Sokolova, E.Y., Varentsov, I.M.Deep array electromagnetic sounding on the Baltic Shield: external excitation model and implications for upper mantle conductivity studies.Tectonophysics, Vol. 445, 1-2, pp. 3-25.Europe, Baltic ShieldGeophysics - magnetics
DS1970-0611
1972
Varfolomeyeva, T.D.Varfolomeyeva, T.D., et al.Study of the Trace Elements in Specimens of Natural CarbonadDoklady Academy of Science USSR, Earth Science Section., Vol. 202, No. 1-6, PP. 191-192.RussiaKimberlite
DS201012-0628
2010
Varga, P.Riguzzi, F., Panza, G., Varga, P., Doglioni, C.Can Earth's rotation and tidal despinning drive plate tectonics?Tectonophysics, Vol. 484, pp. 60-73.MantleTectonics
DS202104-0612
2020
Varga, P.Varga, P., Fodor, C.About the energy and age of the plate tectonics.Terra Nova, 10.1111/ter.12518 7p. PdfMantleplate tectonics

Abstract: Recently, a number of research findings have come to light about the age of plate tectonics, and energies are needed to operate it. The aim of present study is to investigate whether the energy of plate tectonics process was different during the Phanerozoic (Pz) and in earlier eons, and if there is such a discrepancy, whether it can be justified by changes in the processes that able to move the plates. The study will track temporal changes in important components of plate tectonics such as length of mid?ocean ridges, subduction zones and relative oceanic crust coverage during Phanerozoic. Next, it will be examined how the knowledge gained in this way can be reconciled with the results of studies of previous eons. It was found that the temporal variation in kinetic energy of axial rotation due to changes in length of day (LOD) can be assumed as a determining energy which acts on the tectonic plates as in the Phanerozoic as earlier in Archean (Arch) and Proterozoic (Ptz).
DS201705-0863
2017
Vargin, A.V.Nosova, A.A., Dubinina, E.O., Sazonova, L.V., Vargin, A.V., lebedeva, N.M., Khvostikov, V.A., Burmii, Zh.P., Kondrashov, I.A., Tretyachenko, V.V.Geochemistry and oxygen isotopic composition of olivine in kimberlites from the Arkhangelsk Province: contribution of mantle metasomatism.Petrology, Vol. 25, 2, pp. 150-180.Russia, Archangel, Kola PeninsulaDeposit - Grib, Pionerskaya

Abstract: The paper presents data on the composition of olivine macrocrysts from two Devonian kimberlite pipes in the Arkhangelsk diamond province: the Grib pipe (whose kimberlite belongs to type I) and Pionerskaya pipe (whose kimberlite is of type II, i.e., orangeite). The dominant olivine macrocrysts in kimberlites from the two pipes significantly differ in geochemical and isotopic parameters. Olivine macrocrysts in kimberlite from the Grib pipe are dominated by magnesian (Mg# = 0.92-0.93), Ti-poor (Ti < 70 ppm) olivine possessing low Ti/Na (0.05-0.23), Zr/Nb (0.28-0.80), and Zn/Cu (3-20) ratios and low Li concentrations (1.2-2.0 ppm), and the oxygen isotopic composition of this olivine ?18O = 5.64‰ is higher than that of olivine in mantle peridotites (?18O = 5.18 ± 0.28‰). Olivine macrocrysts in kimberlite from the Pionerskaya pipe are dominated by varieties with broadly varying Mg# = 0.90-0.93, high Ti concentrations (100-300 ppm), high ratios Ti/Na (0.90-2.39), Zr/Nb (0.31-1.96), and Zn/Cu (12-56), elevated Li concentrations (1.9-3.4 ppm), and oxygen isotopic composition ?18O = 5.34‰ corresponding to that of olivine in mantle peridotites. The geochemical and isotopic traits of low-Ti olivine macrocrysts from the Grib pipe are interpreted as evidence that the olivine interacted with carbonate-rich melts/fluids. This conclusion is consistent with the geochemical parameters of model melt in equilibrium with the low-Ti olivine that are similar to those of deep carbonatite melts. Our calculations indicate that the variations in the ?18O of the olivine relative the “mantle range” (toward both higher and lower values) can be fairly significant: from 4 to 7‰ depending on the composition of the carbonate fluid. These variations were formed at interaction with carbonate fluid, whose ?18O values do not extend outside the range typical of mantle carbonates. The geochemical parameters of high-Ti olivine macrocrysts from the Grib pipe suggest that their origin was controlled by the silicate (water-silicate) component. This olivine is characterized by a zoned Ti distribution, with the configuration of this distribution between the cores of the crystals and their outer zones showing that the zoning of the cores and outer zones is independent and was produced during two episodes of reaction interaction between the olivine and melt/fluid. The younger episode (when the outer zone was formed) likely involved interaction with kimberlite melt. The transformation of the composition of the cores during the older episode may have been of metasomatic nature, as follows from the fact that the composition varies from grain to grain. The metasomatic episode most likely occurred shortly before the kimberlite melt was emplaced and was related to the partial melting of pyroxenite source material.
DS1960-0104
1960
Varlamov, A.S.Varlamov, A.S., Kikhaylov, I.N., Nikitim, A.A., et al.Geophysical Methods Used in Locating Diamond Deposits of Yakutia.Razved. Geol. Ser., No. 12, PP. 89-97.RussiaKimberlite, Geophysics
DS1960-0308
1962
Varlamov, A.S.Varlamov, A.S., et al.Geophysical Prospecting Methods Used in Locating the Diamond Deposits of Yakutia.International Geology Review, Vol. 4, PP. 271-278.RussiaKimberlite, Geophysics
DS1990-1505
1990
Varlamov, D.A.Varlamov, D.A., Garanin, V.K., Kudrjavtseva, G.P.Mineral inclusions in high grade metamorphism garnetsInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 896-897RussiaMicroscopy, Diamond inclusions
DS1991-0191
1991
Varlamov, D.A.Bulanova, B., Varlamov, D.A., Garanin, V.K., Kudjavtseva, G.P.Chemico-genetic classification of the most important minerals-satellites Of the diamondProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 490-491RussiaMineral chemistry, Genesis
DS1993-1651
1993
Varlamov, D.A.Varlamov, D.A., Garanin, D.A., Kostroviski, S.I.Unusual association of ore minerals in inclusion of garnet from International kimberlite pipe. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 328, No. 5, Feb. pp. 596-600.Russia, YakutiaMineral inclusions, Deposit -International
DS1996-1106
1996
Varlamov, D.A.Perchuk, A.L., Varlamov, D.A.A new type of prograde heterogeneity in garnet based on a study of Great-Caucasus eclogites.Geochemistry International, Vol. 33, No. 8, pp. 101-116.RussiaEclogites, Mineralogy -garnets
DS1996-1468
1996
Varlamov, D.A.Varlamov, D.A., Garanin, V.K., Kostrovitsky, S.I.Exotic high titanium minerals as inclusions in garnets from lower crustaland mantle xenoliths.Doklady Academy of Sciences, Vol. 345A, No. 9, Oct. pp. 352-355.Russia, YakutiaXenoliths, Deposit - International, Sytykan
DS201709-1962
2017
Varlamov, D.A.Borisova, A.Y., Zagrtdenov, N.R., Toplis, M.J., Bohrson, W.A., Nedelec, A., Safonov, O.G., Pokrovski, G.S., Ceileneer, G., Melnik, O.E., Bychkov, A.Y., Gurenko, A.A., Shscheka, S., Terehin, A., Polukeev, V.M., Varlamov, D.A., Gouy, S., De Parseval, P.Making Earth's continental crust from serpentinite and basalt. Goldschmidt Conference, abstract 1p.Mantleperidotites

Abstract: How the Earth's continental crust was formed in the Hadean eon is a subject of considerable debates [1-4]. For example, shallow hydrous peridotites [2,5], in particular the Hadean Earth's serpentinites [6], are potentially important ingredients in the creation of the continental ptoto-crust, but the mechanisms of this formation remain elusive. In this work, experiments to explore serpentinite-basalt interaction under conditions of the Hadean Earth were conducted. Kinetic runs lasting 0.5 to 48 hours at 0.2 to 1.0 GPa and 1250 to 1300°C reveal dehydration of serpentinite and release of a Si-Al-Na-K-rich aqueous fluid. For the first time, generation of heterogeneous hydrous silicic melts (56 to 67 wt% SiO2) in response to the fluid-assisted fertilisation and the subsequent partial melting of the dehydrated serpentinite has been discovered. The melts produced at 0.2 GPa have compositions similar to those of the bulk continental crust [2,3]. These new findings imply that the Earth's sialic proto-crust may be generated via fluid-assisted melting of serpentinized peridotite at shallow depths (?7 km) that do not require plate subduction during the Hadean eon. Shallow serpentinite dehydration and melting may be the principal physico-chemical processes affecting the earliest lithosphere. Making Earth's continental crust from serpentinite and basalt.
DS201810-2346
2018
Varlamov, D.A.Litvin, Yu.A., Kuzyura, A.V., Varlamov, D.A., Bovkun, A.V., Spival, A.V., Garanin, V.K.Interaction of kimberlite magma with diamonds upon uplift from the upper mantle to the Earth's crust.Geochemistry International, Vol. 56, 9, pp. 881-900.Russiadeposit - Nyurbinskaya

Abstract: Interaction between a melt of kimberlite from the Nyurbinskaya pipe (Yakutia) and natural monocrystalline diamonds was studied experimentally at 0.15 GPa and 1200-1250°C in high-pressure and high-temperature Ar gas “bombs.” The loss of diamond weight with slight surface dissolution of diamonds in a Ca carbonate-bearing kimberlite melt over the course of 2 h (the period of kimberlite transport from upper-mantle diamond-forming chambers to the crustal cumulative centers) is 3-4.5%. In 4 and 7-8 days (under the conditions of crustal cumulative centers), the weight of diamond decreases with remarkable bulk dissolution by 13.5 and 24.5-27.5%, respectively. In the run at 0.15 GPa and 1200°C kimberlite and ilmenite (added) melts interact to produce perovskite melt. Both of the melts, rich in titanium minerals, are immiscible with kimberlite melt and therefore cannot influence the diamond dissolution kinetics in the kimberlite melt. The experimental results suggest that precisely the dissolution processes for thermodynamically metastable diamonds in silicate-carbonate kimberlitic magmas are responsible for the effective decrease in the diamond potential of kimberlite deposits. The paper discusses the physicochemical reasons for the decrease in the kimberlite diamond potential during the chemically active history of diamond genesis: from upper-mantle chambers to the explosive release of diamonds and kimberlite material from cumulative centers to the Earth’s surface. The data on experimental physicochemical studies of the origin, analytical mineralogy of inclusions, and isotope geochemistry of diamonds are correlated.
DS201909-2027
2019
Varlamov, D.A.Butvina, V.G., Vorobey, S.S., Safonov, O.G., Varlamov, D.A., Bondarenko, G.V., Shapovalov, Yu.B.Experimental study of the formation of chromium-bearing priderite and yimengite as products of modal mantle metasomatism.Doklady Earth Sciences, Vol. 486, 2, pp. 711-715.Mantlemetasomatism

Abstract: The results of experiments on the synthesis of exotic titanates (priderite and yimengite) simulating metasomatic conditions of alteration of the mantle minerals (chromite and ilmenite) are reported. Ba-free Cr-bearing priderite was synthesized for the first time. Experiments showed the possibility of crystallization of this mineral as a product of the reaction of high-Cr spinel and rutile with hydrous-carbonate fluid (melt) under the conditions of the upper mantle. In particular, the experimental data obtained provide an interpretation of the relationships between K?Cr priderite and carbonate-silicate inclusions in chromites from garnet peridotite of the Bohemian massif. Experimental study of the reaction of chromite and ilmenite with potassic hydrous-carbonate fluid (melt) shows the presence of both titanate phases (priderite and yimengite), the mineral indicators of mantle metasomatism. This provides direct evidence for the formation of yimengite and K?Cr priderite, as well as other titanates, due to mantle metasomatism of the upper mantle peridotite under the conditions of the highest activities of potassium.
DS1983-0612
1983
Varlamov, V.A.Vaganov, V.I., Varlamov, V.A.Structural position and conditions of formation of Kimberlites in Siberian and American platforms. (Russian)Soviet Geology, (Russian), No. 3, pp. 86-89RussiaGeotectonics
DS1983-0613
1983
Varlamov, V.A.Vaganov, V.I., Varlamov, V.A.Structural Position and Condition of Formation of Kimberlites in the Siberian and African Platforms.Soviet Geology, No. 3, PP. 86-89.Russia, South Africa, AfricaTectonics, Structure, Genesis
DS1984-0002
1984
Varlamov, V.A.Afanasev, V.P., Varlamov, V.A., Garanin, V.K.The Abrasion of Minerals in Kimberlites in Relation to the Conditions and Distances of Their Transportation.Soviet Geology And Geophysics, Vol. 25, No. 10, OCTOBER PP. 112-117.RussiaMorphology, Petrography
DS1994-0868
1994
Varlamov, V.A.Kaminsky, F.V., Feldman, A.A., Varlamov, V.A., et al.Prognostication of primary diamond deposits #1The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Section, 12p. 11 figs.Russia, YakutiaDiamond genesis, Area selection, prospecting
DS1995-0910
1995
Varlamov, V.A.Kaminsky, F.V., Feldman, A.A., Varlamov, V.A., Boyko, A.N.Prognostication of primary diamond deposits #2Journal of Geochemical Exploration, Vol. 52, pp. 167-182.RussiaDiamond exploration, Area selection
DS1995-1951
1995
Varlamov, V.A.Vaganov, V.I., Varlamov, V.A., Feldman, A.A., et al.Diamondiferous magmatism: miner agenetic taxons and prediction prospectingmethods.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 649.RussiaMineralogy, Prospecting
DS202107-1101
2018
Varma, C.B.Guha, A., Rani, K., Varma, C.B., Sarwate, N.K., Sharma, N., Mukherjee, A., Kumar, K.V., Pal, S.K., Saw, A.K., Jha, S.K.Identification of potential zones for kimberlite exploration - an Earth observation approach. ChhatarpurThe International Achives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XLII-5 12p. PdfIndia, Madhya PradeshASTER, lineament

Abstract: In the present study, we have prepared the thematic evidence layers for identifying the potential zones of kimberlite emplacement in parts of Chhatarpur district, Madhya Pradesh. These thematic layers or evidence layers are geological structure, alteration zones, lineament density, surface alteration and geomorphic anomaly and these layers are prepared from the remote sensing data. As orientation of the geological structures (i.e fault system) and their density have the major role in the emplacement of kimberlite; both of these evidence layers are integrated using "AND" Boolean Logical Operator. On the other hand, two evidential layers regarded as the proxy to indicate the "surface expressions on kimberlite (i.e. alteration zones and geomorphic anomaly) are combined using "OR" operator as either of these two surface expression is indicative of kimberlite. Consequently, conjugate evidence layers on the surface expressions of kimberlite are integrated with the causative evidence layers of kimberlite emplacement using "AND" operator to identify the potential zones of diamond occurrences. Potential zones of kimberlite are overlaid on the residual gravity anomaly map derived from space-based gravity model of European Improved Gravity of Earth by New Technique (EIGEN6C4) to relate potential zones of kimberlite with the similar structural alignment (delineated in the residual gravity map) of known occurrence of kimberlite. We also have carried out indicator mineral survey around these potential zones and some of the kimberlite specific indicator minerals are identified in the stream sediments within these potential zones.
DS1980-0336
1980
Varma, N.L.Varma, N.L.The Likely Scenarios of Indian Diamond Industry and Trade During the Next Decade.Transcript of Paper From Diamond Seminar, Bombay, 7P.IndiaDiamond Marketing
DS1984-0648
1984
Varma, O.P.Sen, A.K., Varma, O.P.Some aspects of magnetite mineralization associated with the Sung Valley alkaline carbonatite complex, MaghalayaSymposium on chromite deposits of India and related problems of their, pp. 13-14. AbstractIndiaCarbonatite
DS1991-0784
1991
Varma, O.P.Jaireth, S., Sen, A.K., Varma, O.P.Fluid inclusion studies in apatite of the Sung Valley carbonatite northeast India: evidence of melt-fluid immiscibilityJournal of Geological Society India, Vol. 37, June pp. 547-559IndiaCarbonatite, Geochemistry
DS2001-0641
2001
Varmolyuk, V.V.Kuzmin, M.A., Varmolyuk, V.V., Kovalenko, IvanovEvolution of the central Asian 'hot' fields in the Phanerzoic and some problems of plume tectonics.Alkaline Magmatism -problems mantle source, pp. 242-56.AsiaMantle - plumes, hot spots
DS1985-0695
1985
Varne, R.Varne, R.Ancient Subcontinental Mantle: a Source for K-rich Orogenicvolcanics.Geology, Vol. 13, No. 6, JUNE PP. 405-408.AustraliaLeucitites, Ultramafics
DS1989-1542
1989
Varnes, D.J.Varnes, D.J., Radbruch-Hall, D.H., Savage, W.Z.Topographic and structural conditions in areas of gravitational spreading of ridges in the western United StatesUnited States Geological Survey (USGS) Prof. Paper, No. 1496, 28pColorado, MontanaStructure, General-specific regions
DS1920-0351
1927
Varre, W.J. LA.Varre, W.J. LA.Up the Mazaruni for DiamondsBoston: Marshall Jones, 139P., ILLUS.VenezuelaKimberlite, Kimberley, Janlib, Travelogue
DS1930-0206
1935
Varre, W.J. LA.Varre, W.J. LA.Gold, Diamonds and OrchidsNew York: Revell, 298P.VenezuelaKimberlite, Kimberley, Janlib, Travelogue
DS1991-0303
1991
Varsek, J.L.Cook, F.A., Varsek, J.L., Clark, E.A.Proterozoic craton to basin crustal transition in western Canada and its influence on the evolution of the CordilleraCanadian Journal of Earth Sciences, Vol. 28, No. 8, August pp. 1148-1158Alberta, western CanadaCraton, Proterozoic
DS1993-1652
1993
Varsek, J.L.Varsek, J.L., et al.Lithoprobe crustal reflection structure of the southern Canadian Cordillera 2: Coast Mountains transectTectonics, Vol. 12, No. 2, April pp. 334-360British ColumbiaTectonics, Cordillera, Structure
DS1994-0337
1994
Varsek, J.L.Cook, F.A., Varsek, J.L.Orogen scale decollementsReviews of Geophysics, Vol. 32, No. 1, February pp. 37-60GlobalTectonics, Subduction
DS1994-0338
1994
Varsek, J.L.Cook, F.A., Varsek, J.L.Orogen scale decollementsReviews of Geophysics, Vol. 32, No. 1, February pp. 37-60.MantleLithosphere, Subduction
DS1994-1842
1994
Varsek, J.L.Varsek, J.L., Cook, F.A.Three dimensional crustal structure of the Eastern Cordillera, southwestern Canada and northwest United States.Geological Society of America (GSA), Vol. 106, June. pp. 803-23.British Columbia, Western CanadaTectonics, Lithoprobe, Cocorp
DS1970-0317
1971
Varshal, G.M.Ilupin, I.P., Varshal, G.M., Pavlutskaya, V.I., Kelenchuk, G.E.Rare Earth Elements in Yakutian KimberlitesGeochemistry International, Vol. 8, PP. 106-110.RussiaBlank
DS1987-0083
1987
Varshavskii, A.V.Bulanova, G.P., Varshavskii, A.V., Leskova, N.V., Nikishova, L.V.Central inclusions as indicators of growth conditions of natural diamond.(Russian)Fiz. Svoistva I Mineral. Prirod. Almaza Yakutsk, (Russian), 1986 pp. 29-45RussiaDiamond inclusions
DS200612-0195
2005
Varshavsky, A.V.Bulanova, G.P., Varshavsky, A.V., Kotegov, V.A.A venture into the interior of natural diamond genetic information and implications for the gem industry. Part 1, the main types of internal growth structures.Journal of Gemmology, Vol. 29, 7/8, pp. 377-386.RussiaTechnology
DS1975-0549
1977
Vartiainen, H.Kresten, P., Printzlau, I., Rex, D., Vartiainen, H., Woolley, A.New Ages of Carbonatite and Alkaline Ultramafic Rock from Southwest eden and Finland.Geol. Foren. Forhandl., Vol. 99, PP. 62-65.Sweden, Finland, ScandinaviaCarbonatite, Alnoite, Geochronology
DS1975-0595
1977
Vartiainen, H.Paarma, H., Vartiainen, H., Penninkilampi, J.Aspects of Photo geological Interpretation of Sokli Carbonatite Massif.Institute of Mining and Metallurgy. SPECIAL Publishing, PP. 25-29.GlobalRemote, Sensing
DS1975-0884
1978
Vartiainen, H.Vartiainen, H., Kresten, P., Kafkas, Y.Alkaline Lamprophyres from the Sokli Complex, Northern Finland.Comptes Rendus Geol. De la Soc. Finlande., Vol. 50, PP. 59-68.GlobalCarbonatite, Petrology, Alnoite, Damkjernite
DS1980-0337
1980
Vartiainen, H.Vartiainen, H.The Petrography, Mineralogy and Petrochemistry of the Sokli carbonatite Massif, Northern Finland.Bulletin. COMM. GEOL. FINLANDE., No. 313, 126P.GlobalCarbonatite, Alnoite
DS1983-0387
1983
Vartiainen, H.Lappin, A.V., Vartiainen, H.Orbicular and Spherulitic Carbonatites from Sokli and Vuorijarvi.Lithos, Vol. 16, No. 1, PP. 53-60.GlobalMorphology, Fractionation, Silicates
DS1993-0849
1993
Vartiainen, H.Kramm, U., Kogarko, L.N., Kononova, V.A., Vartiainen, H.The Kola alkaline province of the Commonwealth of Independent States (CIS) and Finland: precise rubidium-strontium (Rb-Sr) agesLithos, Vol. 30, No. 1, April pp. 33-44Russia, Commonwealth of Independent States (CIS), FinlandAlkaline rocks, Geochronology
DS200512-0796
2005
Vartiainen, H.O'Brien, H.E., Peltonen, P., Vartiainen, H.Kimberlites, carbonatites and alkaline rocks.Elsevier: Lehtinen, M., Nurmi, P.A., Rama, O.T. eds. Precambrian geology of Finland: key to the evolution, pp.Europe, Finland, FennoscandiaOverview
DS1970-1001
1974
Vartianen, H.Vartianen, H., Woolley, A.R.The Age of the Sokli Carbonatite FIn land and Some Relationships of the North Atlantic Alkaline Igneous Province.Bulletin. COMM. GEOL. FINLANDE., Vol. 46, PP. 81-91.GlobalCarbonatite, Alnoite, Plate Tectonics
DS1975-1251
1979
Vartianen, H.Vartianen, H., Paarma, H.Geological Characteristics of the Sokli Carbonatite Complex, Finland.Economic Geology, Vol. 74, PP. 1296-1306.GlobalUltramafic And Related Rocks
DS2001-1194
2001
Vasanthi, A.Vasanthi, A., Mallick, K.Patterns of occurrence of kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur LattavaramJournal of Geological Society India, Vol. 58, No. 3, pp. 251-60.India, Andhra PradeshGeophysics - gravity, magnetics, Deposit - Wajrakarur
DS2001-1195
2001
Vasanthi, A.Vasanthi, A., Mallick, K.Patterns of occurrence of kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur LattavaraM.Journal Geological Society of India, Vol.58,pp.251-9.India, Andhra PradeshGeophysics - magnetics, Deposit - Wajrakarur - Lattavaram
DS2002-1652
2002
Vasanthi, A.Vasanthi, A., Mallick, K.Pattern of occurrence of kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur Lattavaram region, Andhra Pradesh.COMMENTSJournal of Geological Society of India, Vol. 60, Sept. pp. 3590-51.India, Andhra PradeshGeophysics - corrections
DS200412-2045
2002
Vasanthi, A.Vasanthi, A., Mallick, K.Pattern of occurrence of kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur Lattavaram region, Andhra PradesJournal of Geological Society of India, Vol. 60, Sept. pp. 3590-51.India, Andhra PradeshGeophysics - corrections
DS200512-1127
2005
Vasanthi, A.Vasanthi, A., Mallick, K.Bouguer gravity anomalies and occurrence patterns of kimberlite pipes in Narayanpet Maddur regions, Andhra Pradesh, India.Geophysics, Vol. 70, 1, Jan-Feb. pp. J13-J24.India, Andhra PradeshGeophysics - gravity
DS200512-1128
2005
Vasanthi, A.Vasanthi, A., Mallick, K.Bouguer gravity modeling of central Cuddaph Basin.Journal of the Geological Society of India, Vol. 66, 2, pp. 171-184.IndiaGeophysics - gravity
DS200612-1471
2005
Vasanthi, A.Vasanthi, A., Mallick, K.Occurrence pattern of kimberlite pipes as reflected by gravity and magnetic anomalies.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 69-70.India, Andhra Pradesh, Dharwar CratonGeophysics
DS200612-1472
2006
Vasanthi, A.Vasanthi, A., Mallick, K.Further confirmation of kimberlite/lamproite occurrences in concentric ring pattern in Andhra Pradesh. Wajrakarur, Chigicherla, Chelima, NarayanpetJournal of the Geological Society of India, Vol. 68, August pp. 332-333.IndiaTectonics - kimberlites
DS201801-0044
2017
Vasanthi, A.Pandey, O.P., Chandrakala, K., Vasanthi, A., Satish Kumar, K.Seismically imaged shallow and deep crustal structure and potential field anomalies across the Eastern Dharwar Craton, south Indian shield: possible geodynamical implications.Journal of Asian Earth Sciences, in press available, 11p.Indiageophysics - seismics

Abstract: The time-bound crustal evolution and subsequent deformation of the Cuddapah basin, Nellore Schist Belt and Eastern Ghats terrain of Eastern Dharwar Craton, which have undergone sustained geodynamic upheavals since almost 2.0 billion years, remain enigmatic. An attempt is made here to integrate newly available potential field data and other geophysical anomalies with deep seismic structure, to examine the generative mechanism of major crustal features, associated with this sector. Our study indicates that the initial extent of the Cuddapah basin sedimentation may have been much larger, extending by almost 50-60?km west of Tadipatri during Paleoproterozoic period, which subsequently shrank due to massive erosion following thermal uplift, caused by SW Cuddapah mantle plume. Below this region, crust is still quite warm with Moho temperatures exceeding 500?°C. Similarly, Nallamalai Fold Belt rocks, bounded by two major faults and extremely low gravity, may have occupied a large terrain in western Cuddapah basin also, before their abrasion. No geophysical signatures of thrusting are presently seen below this region, and thus it could not be an alien terrain either. In contrast, Nellore Schist Belt is associated with strikingly high positive gravity, possibly caused by a conspicuous horst structure and up dipping mafic crustal layers underneath, that resulted due to India-east Antarctica collision after the cessation of prolonged subduction (1.6-0.95?Ga). Further, the crustal seismic and gravity signatures would confirm presence of a totally distinct geological terrain east of the Cuddapah basin, but the trace of Eastern Ghats Belt is all together missing. Instead, all the geophysical signatures, point out to presence of a Proterozoic sedimentary terrain, east of Nellore Schist Belt. It is likely that the extent of Prorerozoic sedimentation was much larger than thought today. In addition, presence of a seismically detected Gondwana basin over Nellore Schist Belt, apart from some recently discovered similar subsurface Gondwana occurrences in intracratonic parts, would indicate that Dharwar Craton was rifting even during Gondwana period, thereby challenging the long held view of cratonic stability.
DS201805-0969
2018
Vasanti, A.Pandey, O.P., Chandrakala, K., Vasanti, A., Kumar, K.S.Seismically imaged shallow and deep crustal structure and potential field anomalies across the Eastern Dharwar Craton, South Indian shield: possible geodynamical implications.Journal of Asian Earth Sciences, Vol. 157, pp. 302-316.Indiageophysics - seismics

Abstract: The time-bound crustal evolution and subsequent deformation of the Cuddapah basin, Nellore Schist Belt and Eastern Ghats terrain of Eastern Dharwar Craton, which have undergone sustained geodynamic upheavals since almost 2.0 billion years, remain enigmatic. An attempt is made here to integrate newly available potential field data and other geophysical anomalies with deep seismic structure, to examine the generative mechanism of major crustal features, associated with this sector. Our study indicates that the initial extent of the Cuddapah basin sedimentation may have been much larger, extending by almost 50-60?km west of Tadipatri during Paleoproterozoic period, which subsequently shrank due to massive erosion following thermal uplift, caused by SW Cuddapah mantle plume. Below this region, crust is still quite warm with Moho temperatures exceeding 500?°C. Similarly, Nallamalai Fold Belt rocks, bounded by two major faults and extremely low gravity, may have occupied a large terrain in western Cuddapah basin also, before their abrasion. No geophysical signatures of thrusting are presently seen below this region, and thus it could not be an alien terrain either. In contrast, Nellore Schist Belt is associated with strikingly high positive gravity, possibly caused by a conspicuous horst structure and up dipping mafic crustal layers underneath, that resulted due to India-east Antarctica collision after the cessation of prolonged subduction (1.6-0.95?Ga). Further, the crustal seismic and gravity signatures would confirm presence of a totally distinct geological terrain east of the Cuddapah basin, but the trace of Eastern Ghats Belt is all together missing. Instead, all the geophysical signatures, point out to presence of a Proterozoic sedimentary terrain, east of Nellore Schist Belt. It is likely that the extent of Prorerozoic sedimentation was much larger than thought today. In addition, presence of a seismically detected Gondwana basin over Nellore Schist Belt, apart from some recently discovered similar subsurface Gondwana occurrences in intracratonic parts, would indicate that Dharwar Craton was rifting even during Gondwana period, thereby challenging the long held view of cratonic stability.
DS202108-1312
2021
Vasanti, A.Vasanti, A., Singh, A.P., Kumar, N., Nageswara Rao, B., Satyakumar, A.V., Santosh, M.Crust-mantle structure and lithospheric destruction of the oldest craton in the Indian shield.Precambrian Research, Vol. 362, 16p. PdfIndiacraton

Abstract: The Singhbhum craton is among the five Archean cratons of Peninsular India that preserves some of the oldest continental nuclei. In this work, we present a new and complete Bouguer gravity map of this craton with insights into its deep crust-mantle structure, lithospheric thickness and density variations beneath this craton. The conspicuous presence of high-order residual gravity low anomalies, together with low estimated densities, suggests voluminous presence of Singhbhum granitic batholiths that built the dominant crustal architecture. The isolated residual gravity highs correspond to the mafic and ultramafic volcanic suites like, Dhanjori, Simlipal and Dalma, while the relatively low gravity anomalies observed over the western volcanic suites like Malangtoli, Jagannathpur and Ongarbira, indicate their relatively felsic nature. The estimated lithospheric thickness of about ~ 130 km below the granitic batholithic region, and about 112 km beneath the Precambrian volcanic terranes, together with low effective elastic thickness (Te,) of only about 31 km, suggest a thin and weak lithosphere. The craton witnessed extensive lithospheric destruction with the removal of nearly 100-150 km of the cratonic root. The decratonization may be linked to subduction during the Paleo-Mesoproterozoic period, together with mantle plumes at different times, suggesting a combined mechanical, thermal and chemical erosion of the cratonic keel.
DS201012-0053
2010
Vascncelos, K.K.F.Bezerra, U.T., Vascncelos, K.K.F., Wegner, R.R.New hardness scale. Comparison of Mohs with Vickers.International Mineralogical Association meeting August Budapest, abstract p. 418.TechnologyHardness scale
DS201112-1081
2010
Vasconcellos, E.M.G.Vasconcellos, E.M.G., Lopes, A.P., Fischer, G., Marchese, C., Reis Neto, J.M.Microtomografia de raios x applicada ao estudo de inclusoes em diamantes.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 44-45.South America, BrazilTomography - inclusions
DS1989-1337
1989
Vasconcellos, M.B.A.Santosh, M., Iyer, S.S., Vasconcellos, M.B.A., Enzweiler, J.Late Precambrian alkaline plutons in southwest India:geochronologic and rare earth element constraints on Pan-African magmatismLithos, Vol. 24, pp. 65-79IndiaAlkaline plutons, alkaline rocks, Pan African magmatism, Rare earths
DS201510-1812
2015
Vasconcelos, L.Vasconcelos, L.Geoethics - Africa needs to be respected and heard.Journal of African Earth Sciences, Vol. 111, p. 287. 1p.AfricaCSR - ethics

Abstract: The Journal of African Earth Sciences (Vol. 111, 2015, page 287) has published a "Short Note" entitled "Geoethics: Africa must be respected and heard!" by Lopo Vasconcelos, Jesus Martinez-Frias and Aberra Mogessie, raising an important issue: the need to include ethical issues in the educational systems of Africa. Reference is made to a project aiming at "providing the entire African continent with a roadmap to face the target of geoscience education within a wide scope and a multidisciplinary approach" GEO-ERA (GEOscience Education Roadmap for Africa) promoted and coordinated by the IUGS-Commission on Geoscience Education, Training and Technology Transfer (IUGS-COGE) and the Geological Society of Africa (GSAf). Considering that Education and Ethics must go along together, GSAf and IAGETH (International Association for Geoethics) signed in 2013, after the 24th Colloquium of African Geology, CAG24 (Addis Ababa) a Memorandum of Understanding in order to accomplish this and other goals.
DS201312-0937
2013
Vasconcelos, M.A.R.Vasconcelos, M.A.R., Crosta, A.P., Reimold, W.U., Goes, A.M., Kenkmann, T., Poelchau, M.H.The Serra da Cangalha impact structure, Brazil: geological, stratigraphic and petrographic aspects of a recently confirmed impact structure.Journal of South American Earth Sciences, Vol. 45, pp. 316-330.South America, BrazilMeteorite
DS201812-2794
2018
Vasconcelos, M.A.R.Crosta, A.P., Reimold, W.V., Vasconcelos, M.A.R., Hauser, N., Oliveira, G.J.G., Maziviero, M.V., Goes, A.M.Impact cratering: the South American record. Part 2.Chemie der Erde, doi.org/10.1016/j ,chemer.2018.09.002 30MBSouth America, Brazilmeteorite

Abstract: In the first part of this review of the impact record of South America, we have presented an up-to-date introduction to impact processes and to the criteria to identify/confirm an impact structure and related deposits, as well as a comprehensive examination of Brazilian impact structures. The current paper complements the previous one, by reviewing the impact record of other countries of South America and providing current information on a number of proposed impact structures. Here, we also review those structures that have already been discarded as not being formed by meteorite impact. In addition, current information on impact-related deposits is presented, focusing on impact glasses and tektites known from this continent, as well as on the rare K-Pg boundary occurrences revealed to date and on reports of possible large airbursts. We expect that this article will not only provide systematic and up-to-date information on the subject, but also encourage members of the South American geoscientific community to be aware of the importance of impact cratering and make use of the criteria and tools to identify impact structures and impact deposits, thus potentially contributing to expansion and improvement of the South American impact record.
DS201907-1539
2019
Vasconcelos, M.A.R.Crosta, A.P., Reimold, W.U., Vasconcelos, M.A.R., Hauser, N., Oliveira, G.J.G.Impact cratering: the South American record - Part 2. Brazil was covered in Part 1. Geochemistry, Vol. 79, pp. 191-220.South Americameteorite

Abstract: In the first part of this review of the impact record of South America, we have presented an up-to-date introduction to impact processes and to the criteria to identify/confirm an impact structure and related deposits, as well as a comprehensive examination of Brazilian impact structures. The current paper complements the previous one, by reviewing the impact record of other countries of South America and providing current information on a number of proposed impact structures. Here, we also review those structures that have already been discarded as not being formed by meteorite impact. In addition, current information on impact-related deposits is presented, focusing on impact glasses and tektites known from this continent, as well as on the rare K-Pg boundary occurrences revealed to date and on reports of possible large airbursts. We expect that this article will not only provide systematic and up-to-date information on the subject, but also encourage members of the South American geoscientific community to be aware of the importance of impact cratering and make use of the criteria and tools to identify impact structures and impact deposits, thus potentially contributing to expansion and improvement of the South American impact record.
DS200912-0198
2009
Vasconcelos, P.Eby, G.N., Vasconcelos, P.Geochronology of the Arkansas alkaline province of southeastern United States.Journal of Geology, Vol. 117, Sept. pp. 615-626.United States, ArkansasCarbonatite, lamproites
DS201312-0700
2013
Vasconcelos, P.M.Perez-Valera, L.A., Rosenbaum, G., Sabchez-Gomez, M., Azor, A., Fernadez-Soler, J.M., Perez-Valera, F., Vasconcelos, P.M.Age distribution of lamproites along the Socovos fault ( southern Spain) and lithospheric scale tearing.Lithos, Vol. 180-181, pp. 252-263.Europe, SpainLamproite
DS201312-0701
2013
Vasconcelos, P.M.Perlingeiro, G., Vasconcelos, P.M., Knesel, K.M., Thiede, D.S., Cordani, U.G.40 Ar/39/Ar geochronology of the Fernando de Noronha Archipelago and implications for the origin of alkaline volcanism in the NE Brazil.Journal of Volcanology and Geothermal Research, Vol. 249, pp. 140-154.South America, BrazilAlkalic
DS202005-0728
2020
Vasconcelos, P.M.Conceicao, F.T., Vasconcelos, P.M., Godoy, L.H., Navarro, G.R.B.40Ar/40Ar geochronological evidence for multiple magmatic events during the emplacement of Tapira alkaline-carbonatite complex, Minas Gerais, Brazil.Journal of South American Earth Sciences, Vol. 97, 102416, 7p. PdfSouth America, Brazil, Minas Geraiscarbonatite

Abstract: The Alto Parnaíba Igneous Province (APIP) is a voluminous magmatic province composed of various alkaline-carbonatite complexes emplaced in the Brasilia Mobile Belt during the Cretaceous. Relative timing of emplacement of silicate and carbonate magmas in most of these complexes remains mostly unresolved due to conflicting geochronological results. To determine the duration of magmatism and to test the possible existence of multiple magmatic events, we employ 40Ar/39Ar phlogopite single crystal dating to determine the history of magma emplacement at the Tapira alkaline-carbonatite complex, Minas Gerais, Brazil. The new single crystal data indicate at least two magmatic events during the emplacement of this complex, the first at > 96.2 ± 0.8 Ma and the second at 79.15 ± 0.6 Ma. The first igneous event was responsible for emplacement of the silicate plutonic series, while the second event corresponds to the emplacement of primarily carbonatitic magmas, generating metasomatic phlogopite alteration in bebedourites. The ages of intrusion and cooling of the alkaline-carbonatite complexes in the APIP must be investigated in other complexes to determine if intrusion intervals of ~17 Ma or more are common regionally. Protracted intrusive events, if related to magma generation by passage of South America over a stationary Trindade plume, requires complex ponding and lateral magma flow below a slow-moving continent.
DS1987-0647
1987
Vasconsellos, M.B.A.Santosh, M., Thampi, P.K., Iyer, S.S., Vasconsellos, M.B.A.Rare earth element geochemistry of the Munnar carbonatite,centralKeralaJournal of Geo. Soc. India, Vol. 29, March pp. 335-343IndiaRare earths, Carbonatite
DS202205-0696
2022
Vaselev, E.A.Klepikov, I.V., Vaselev, E.A., Antonov, A.V. Regeneration growth as one of the principal stages of diamond crystallogenesis.Minerals ( MDPI), Vol. 12, 3, p. 327 16p.Mantlediamond morphology

Abstract: Revealing the internal structure of diamonds is key to understanding the general regularities of crystal growth and dissolution. This paper presents and summarizes data on the internal structure of diamonds of different morphological types, colors and defect-impurity composition. In order to provide a comprehensive explanation of the stages of diamond growth, crystals and plates were observed, and panchromatic cathodoluminescence and photoluminescence techniques were applied. This article considers the mechanism of tangential growth from existing surfaces (regeneration growth) as an intermediate stage between normal and tangential crystal growth. The regeneration growth is very fast due to the absence of the limiting stage-nucleation of a new atomic layer. Cuboid diamonds were refaceted to stepped octahedrons by the regeneration growth mechanism. A schematic model of crystal habit transformation due to regeneration growth explains the internal structure of crystals in connection with their morphology and thermal history. The main variants of regeneration stage and its morphological manifestations were demonstrated. Most diamonds pass through the regeneration stage, and in many cases, it was a stage of growth termination.
DS2001-0313
2001
Vaselli, O.Falus, G., Szabo, C., Vaselli, O.Mantle upwelling within the Panoonian Basin: evidence from xenolith lithology and mineral chemistry.Terra Nova, Vol. 12, No. 6, Dec. pp. 295-302.Austria, RomaniaPeridotite xenoliths
DS2002-0095
2002
Vaselli, O.Bali, E.O., Szabo, C., Vaselli, O., Torok, K.Significance of silicate melt pockets in upper mantle xenoliths from Bakony Balaton Highland volcanic fieldLithos, Vol.61, 1-2, March, pp. 79-102.HungaryXenoliths - silicates ( not specific to diamond)
DS200412-0446
2004
Vaselli, O.Dessai, A.G., Markwich, A., Vaselli, O., Downes, H.Granulite and pyroxenite xenoliths from the Deccan Trap: insights into the nature and composition of the lower lithosphere beneaLithos, Vol. 78, 3, Nov. pp. 263-290.IndiaDharwar Craton, crust-mantle transition
DS1999-0767
1999
Vasey, J.Vasey, J.De Beers technical competencies and how they could find an application In the north.Mining in the Arctic, Udd and Keen editors, Balkema, pp. 53-61.Northwest TerritoriesMining - technology, techniques
DS1999-0749
1999
Vasievski, A.N.Tychkov, S.A., Rychkova, E.V., Vasievski, A.N., ChervovThermal convection in subcontinental upper mantle and its effect on geophysical fields.Russian Geology and Geophysics, Vol. 40, No. 9, pp. 1253-67.MantleGeophysics - geothermometry
DS1985-0647
1985
Vasilenko, G.P.Strizhkova, A.A., Vasilenko, G.P., Zalishchak, B.L.Discovery of Picrite Basalts in the Verkhne Ussuri Ore Region. (russian)Magmat. Rudn. Raionov Dalnego Vostoka, (Russian), pp. 168-170RussiaBlank
DS1985-0696
1985
Vasilenko, V.B.Vasilenko, V.B., Kuznetsova, L.G., Kholodova, L.D.Petrochemistry of calcium oxide and phosphorous pentoxide in Kimberlites and problem of the origin of apatite rocks in Seligdar (Aldan) USSR.(Russian)Trudy Institute Geol. Geofiz. Akad. Nauk SSSR, (Russian), No. 625, pp. 171-178RussiaPetrology
DS1986-0830
1986
Vasilenko, V.B.Vasilenko, V.B., Kuzetsova, L.G.Petrochemical model of the kimberlite formation of YakutiaSoviet Geology and Geophysics, Vol. 27, No. 7, pp. 73-83RussiaPetrology, Kimberlite
DS1989-1543
1989
Vasilenko, V.B.Vasilenko, V.B., Kryukov, A.V., Kuznetsova, L.G.Petrochemical types of alkali-ultrabasic rocks of the Chadobets UpliftSociet Geology and Geophysics, Vol. 30, No. 8, pp. 43-48RussiaPetrology, Mentions kimberlite pipes
DS1990-0452
1990
Vasilenko, V.B.Entin, A.R., Zaitsev, A.I., Nenshev, N.I., Vasilenko, V.B., OrlovSequence of geological events related to the intrusion of the Tomtor massifSoviet Geology and Geophysics, Vol. 31, no, 12, pp. 39-47RussiaCarbonatite, Tomtor
DS1994-1843
1994
Vasilenko, V.B.Vasilenko, V.B., et al.Petrochemistry and diamond grade of the kimberlites of Yakutia.(Russian)Doklady Academy of Sciences Nauk, (Russian), Vol. 338, No. 1, Sept. pp. 85-88.Russia, YakutiaGeochemistry, Diamond grade
DS1995-1975
1995
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N., Kuznetsova, L.G.Chemism and diamond content of kimberlites of YakutiaRussian Geology and Geophysics, Vol. 36, No. 9, pp. 68-78.Russia, YakutiaPetrochemistry, geochemistry, Kimberlites, diamond genesis
DS1995-1976
1995
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N., Kuznetsova, L.G., et al.Petrochemical types of kimberlites of the major diamond deposits ofYakutia.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 650-652.Russia, YakutiaGeochemistry, Basaltoid kimberlites
DS1996-1469
1996
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N., et al.Petrochemistry and diamond content of Yakutian kimberlitesDoklady Academy of Sciences, Vol. 340, No. 2, March., pp. 156-161.Russia, YakutiaPetrology, Diamond content
DS1996-1470
1996
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N., Kuznetsova, L.G., SerenkoPetrochemical model of the Mir kimberlite pipeRussian Geology and Geophysics, Vol. 37, No. 2, pp. 88-101.RussiaGeochemistry, petrology, model, Deposit -Mir
DS2000-0974
2000
Vasilenko, V.B.Vasilenko, V.B., Zinchuk Krasavchikov, Budaev, KuznetsCriteria for petrochemical identfication of kimberlitesRussian Geology and Geophysics, Vol.41,12,pp.1697-1709., Vol.41,12,pp.1697-1709.RussiaPetrology - classification
DS2000-0975
2000
Vasilenko, V.B.Vasilenko, V.B., Zinchuk Krasavchikov, Budaev, KuznetsCriteria for petrochemical identfication of kimberlitesRussian Geology and Geophysics, Vol.41,12,pp.1697-1709., Vol.41,12,pp.1697-1709.RussiaPetrology - classification
DS2000-0976
2000
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N., Kuznetsova, L.G.Autolithic kimberlites as products of the viscous differentiation of kimberlite melts in diatremes.Petrology, Vol. 8, No. 5, pp. 495-504.RussiaKimberlite - diatremes, magmatism
DS2001-1196
2001
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N., Kuznetsova, L.G.On the correlation between the compositions of mantle inclusions and petrochemical varieties of kimberlitesPetrology, Vol. 9, No. 2, pp. 179-189.Russia, YakutiaDiatremes - geochemistry
DS200512-1129
2005
Vasilenko, V.B.Vasilenko, V.B., Zinchuk, N.N.Mantle plumes as a determining factor of vertical migration of magma generation zones, fixed from the bulk kimberlite compositions.Plumes and problems of deep sources of alkaline magmatism, pp. 96-114.MantleMagmatism
DS200812-0632
2007
Vasilenko, V.B.Lapin, A.V., Tolstov, A.V., Vasilenko, V.B.Petrochemical characteristics of the kimberlites in the Middle Markha region with application to the problem of the geochemical heterogeneity of kimberlites.Geochemistry International, Vol. 45, 12, Dec. pp. 1197-1209.Russia, YakutiaGeochemistry - comparison Zolotitsa and Grib
DS200812-1207
2008
Vasilenko, V.B.Vasilenko, V.B., Tolstov, A.V., Minin, V.A., Kuznetsova, L.G., Surkov, N.V.Normative quartz as an indicator of the mass transfer intensity during the postmagmatic alteration of the Botuobinskaya pipe kimberlites ( Yakutia).Russian Geology and Geophysics, Vol. 49,no. 12, pp. 894-907.Russia, YakutiaDeposit - Botuobinskaya
DS200912-0765
2009
Vasilenko, V.B.Tolstov, A.V., Minin, V.A., Vasilenko, V.B., Kuznetsova, L.G., Razumov, A.N.A new body of highly Diamondiferous kimberlites in the Nakyn field of the Yakutian kimberlite province.Russian Geology and Geophysics, Vol. 50, 3, pp. 162-173.RussiaMineral chemistry
DS200912-0791
2009
Vasilenko, V.B.Vasilenko, V.B.Mantle plumes and lithosphere thickness are factors governing magmas formation in the Yakutian Diamondiferous province.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, Yakutia, SiberiaKimberlites - chemistry
DS201012-0814
2010
Vasilenko, V.B.Vasilenko, V.B., Tolstov, A.V., Kuznetsova, L.G., Minin, V.A.Petrochemical evaluation of the diamond potentials of Yakutian kimberlite fields.Geochemistry International, Vol. 48, 4, pp. 346-354.RussiaMineralogy
DS201212-0751
2012
Vasilenko, V.B.Vasilenko, V.B., Kuznetsova, L.G., Minin, V.A., Tolstov, A.V.Behavior of major and rare earth elements during the postmagmatic alteration of kimberlites.Russian Geology and Geophysics, Vol. 53, pp. 62-76.RussiaAlteration
DS201906-1356
2019
Vasilev, E.Vasilev, E., Petrovsky, V., Kozlov, A., Antonov, A., Kudryatsev, A., Orekhova, K.The story of one diamond: the heterogeneous distribution of the optical centres within a diamond crystal from the Ichetju placer, northern Urals.Mineralogical Magazine, in press availableRussia, Uralsdiamond crystallography

Abstract: We have investigated a diamond crystal that consists of several misorientated subgrains. The main feature of the crystal is the dark in the cathodoluminescence core that has “estuary-like” boundaries extending along the subgrain interfaces. The core has more than 3100 ppm of nitrogen, and the share of the B form is more than 95%; the absorbance of the centre N3VH at 3107 cm -1 reaches 75 cm-1. The N3 centre’s absorbance, as well as N3 luminescence, is absent in the core. In the outer part of the crystal, the bright blue luminescence of the N3 centre is registered, and the N3 absorbance reaches 5.3 cm-1. These observations may be explained by the conversion of N3 centres to N3VH after attaching a hydrogen atom. After the full conversion of the N3 centres, the diamond becomes darker under CL. We hypothesize the dark core has a specific shape due to the post-growth diffusion of the hydrogen.
DS202008-1454
2020
Vasilev, E.Vasilev, E., Kriulina, G., Klepikov, I.Luminescence of natural diamond in the NIR range.Physics and Chemistry of Minerals, Vol. 47, 31 6p. PdfRussialuminesence

Abstract: Natural diamond remains the source of many interesting effects and finds that are difficult to reproduce or detect in synthetic crystals. Herein, we investigate the photoluminescence (PL) of more than 2000 natural diamonds in the range 800-1050 nm. PL spectra were registered with excitation at 405, 450, 488 (Ar+), and 787 nm. The investigation revealed several systems that were not previously described. Some new dislocation-related systems were discovered in the spectra of crystals with signs of plastic deformation. They are four sets of doublets 890/900.3 nm, 918/930 nm, 946.5/961.5 nm, and 981/994 nm; four lines at 946, 961.5, 986, and 1020 nm. In low-nitrogen diamonds, they are accompanied by a line at 921 nm. Unreported vibronic systems with zero-phonon lines at 799.5, 819.6, 869.5, and 930 nm were revealed. In most cases, the systems were accompanied with doublet 883/885 of the simplest Ni-related center. We assigned these systems to Ni-related centers of different complexity. The results expand opportunities to restore growth conditions and thermal history of diamond crystals. The detection of new shallow centers expands the prospects of diamond as an optic and semiconductor material for applications in the NIR range.
DS202010-1883
2019
Vasilev, E.Vasilev, E., Kozlov, A.V.Hydrogen in diamond and a thermal history of diamond crystals. *** abst engResearchgate *** in Russ, 13p. Pdf 330360071MantleFTIR

Abstract: We have performed an analysis of the cases of synchronism in th egrowth temperature in local zones of diamond crystals and the concentration of hydrogen in them.The considered cases were observed by the authors and fined out in the iterature. Possible causes of the simbatic change in the crystal growth temperature and the concentration of hydrogen in it are considered.The determination of the temperature change over the zones was carried out on the basis of local FTIR spectroscopy from the ratio of the nitrogen concentration in the form of defects in the crystal structure of A and B1, and size the B2 defects.The change in the hydrogen concentration in various zones of diamond crystals was estimated from the 3107cm-1 band of the hydrogen-containing defect. It is shown that in the analyzed cases the concentration of hydrogen in diamond is determined mainly by its content in the growth medium.We accept the obtained results as evidence of the participation of hydrogen in the heat transfer in mantle mineral-forming systems.
DS202102-0216
2021
Vasilev, E.Pavlushkin, A., Zedgenizov, D., Vasilev, E., Kuper, K.Morphology and genesis of ballas and ballas-like diamonds.MDPI Crystals, Vol. 11, 17 dx.doi.org/ 103390/ Qcrystal11010017 24p. PdfRussia, Yakutia, Urals, South America, Brazildeposits - Mir, Udachnaya, Aikal, Yubilenya

Abstract: Ballas diamond is a rare form of the polycrystalline radial aggregate of diamonds with diverse internal structures. The morphological features of ballas diamonds have experienced repeated revision. The need that this paper presents for development of a crystal-genetic classification was determined by a rich variety of combined and transitional forms of ballas-like diamonds, which include aggregates, crystals, and intergrowths. The new crystal-genetic classification combines already-known and new morphological types of ballas as well as ballas-like diamonds discovered in the placers of Yakutia, the Urals, and Brazil. The ballas-like diamond forms include spherocrystals, aggregates with a single crystal core, split crystals, radial multiple twin intergrowths, and globular crystals. The crystal genetic scheme of the evolution of ballas and ballas-like diamonds is a sequence of the morphological types arranged in accordance with the conventional model of the dependence of the mechanism and diamond growth from carbon supersaturation developed by I. Sunagawa. The evolution of the growth forms of ballas and ballas-like diamonds was tracked based on the macrozonal structure of diamonds varying from a flat-faced octahedron to a fibrous cuboid with its transition forms to the radiating crystal aggregates. The morphological diversity of the ballas-like diamonds depends on the level of supersaturation, and abrupt changes of the level of supersaturation engender abrupt changes in a mechanism of crystal growth. The change in the rate of growth under the influence of adsorption and absorption of the mechanic impurities accompanied the sudden appearance of the autodeformation defects in the form of splitting and multiple radial twinning of crystals. The spherical shape of Yakutia ballas-like diamonds is due to the volumetric dissolution that results in the curved-face crystals of the "Urals" or "Brazilian" type associated with ballas diamonds in placers.
DS202204-0525
2022
Vasilev, E.Klepikov, I., Vasilev, E.Regeneration growth as one of the principal stages of diamond crystalogenesis.MDPI, doi: 10.3390/min12030327Russiadiamond morphology

Abstract: Revealing the internal structure of diamonds is key to understanding the general regularities of crystal growth and dissolution. This paper presents and summarizes data on the internal structure of diamonds of different morphological types, colors and defect-impurity composition. In order to provide a comprehensive explanation of the stages of diamond growth, crystals and plates were observed, and panchromatic cathodoluminescence and photoluminescence techniques were applied. This article considers the mechanism of tangential growth from existing surfaces (regeneration growth) as an intermediate stage between normal and tangential crystal growth. The regeneration growth is very fast due to the absence of the limiting stage-nucleation of a new atomic layer. Cuboid diamonds were refaceted to stepped octahedrons by the regeneration growth mechanism. A schematic model of crystal habit transformation due to regeneration growth explains the internal structure of crystals in connection with their morphology and thermal history. The main variants of regeneration stage and its morphological manifestations were demonstrated. Most diamonds pass through the regeneration stage, and in many cases, it was a stage of growth termination.
DS202205-0725
2021
Vasilev, E.Vasilev, E., Kriulina, G.Y., Garanin, V.K.Spectroscopy of diamonds from the M.V. Lomonosov deposit.Geology of Ore deposits, Vol. 63, pp. 668-684. pdfRussiadeposit - Lomonosov

Abstract: Diamond crystals from the M.V. Lomonosov deposit (Archangelsk oblast, Russia) were studied by luminescence and infrared spectroscopy. Three groups of crystals were distinguished according to their morphology, thermal history, and photoluminescence. The structural diversity of yellow cuboids typical for the deposit is demonstrated. New photoluminescence systems among the low-temperature cuboid crystals are observed.
DS200812-1208
2007
Vasilev, E.A.Vasilev, E.A., Sofroneev, S.V.Zoning of diamonds from the Mir kimberlite pipe: results of Fourier transformed infrared spectroscopy.Geology of Ore Deposits, Vol. 49, 6, pp. 784-791.Russia, YakutiaDeposit - Mir
DS201902-0329
2019
Vasilev, E.A.Vasilev, E.A., Kozlov, A.V.Hydrogen in diamond and a thermal history of diamond crystals.Researchgate, doi:10.30695/zrmo/2018.1476.05 1p. Abs Eng. 11p. RUSRussiaspectroscopy
DS201907-1580
2018
Vasilev, E.A.Vasilev, E.A., Klepikov, I.V., Antonov, A.V.Rounded diamond crystals with mixed growth mechanism from alluvial placers of the Krasnovishersky district, the Urals.Proceedings of the Russian Mineralogical Society, pt. CXL VII no. 4, 1p. Abstract in Eng.Russiadiamond morphology
DS202003-0368
2019
Vasilev, E.A.Vasilev, E.A., Klepikov, I.V., Lukianova, L.I.Comparison of diamonds from the Rassolninskaya depression and modern alluvial placers of the Kranovishersky district ( Ural region).Geology of Ore Deposits, Vol. 61, 7, pp. 598-605. pdfRussia, Uralsdiamond morphology

Abstract: Three hundred thirty-six diamonds from deposits of the Rassolninskaya depression and 144 crystals from recent alluvial placers of the Krasnovishersky district were studied by IR absorption and photoluminescence spectroscopy. It is shown that crystals from the Rassolninskaya depression have a close-to-normal distribution for the nitrogen concentration. The average nitrogen content is 725 ppm, and no nitrogen-free crystals were detected. A sampling from recent alluvial placers contains 25% crystals with a nitrogen concentration smaller than 150 ppm; 3% of them are nitrogen-free. Among crystals from the Rassolninskaya depression, 12% are octahedral, 80% rhombododecahedral, and only one crystal has relicts of cubic faces. The collection from recent placers contains 3% cubic crystals, 10% individuals with relicts of cubic faces, 16% octahedroids, and 66% dodecahedra. Alluvial diamonds are often encountered with crescent-shaped cracks; however, they were observed only on a single crystal from the Rassolninskaya depression. It has been revealed that among alluvial placer diamonds, up to 95% of crystals contain nitrogen in the form of B1 defects. Thus, first, in morphological and structural-mineralogical features, diamonds from the Rassolninskaya depression differ from crystals of the nearest recent alluvial placers; second, they may belong to primary deposits based on the set of their characteristics.
DS202004-0540
2019
Vasilev, E.A.Vasilev, E.A., Klepikov, I.V., Kozlov, A.V., Antonov, A.V.The nature of the elongated form of diamond crystals from Urals ( Russia) placers.Journal of Mining Institute * not sure if in english?, Vol. 239, 5, pp. 492-496.Russiadiamond crystallography

Abstract: The article presents the results of a study of the internal structure of highly elongated diamond crystals from placers in the Krasnovishersky district of the Urals. Very elongated crystals are found within diamond-bearing placer with unrevealed primary sources. Determining the conditions of such crystals formation can help one to determine the primary deposits type. There are three hypotheses for the formation of the elongated shape of such crystals: 1) crystals initially elongated along the <100> (strongly distorted octahedra); 2) individual crystals of columnar aggregates; 3) elongated crystals fragments. To study the internal structure, we selected three most elongated individuals of the 155 crystals samples. The study of the internal structure of selected crystals with the usage of photoluminescent (PL) tomography, cathodoluminescence (CL), and optical microscopy has shown that these samples are fragments of larger single crystals. CL imaging allowed to determine slip lines within the crystal's volume. The recorded PL spectra show the 912, 946, and 986 nm peaks, which are characteristic of crystals with plastic deformation. The revealed features are indicators of plastic deformation accompanying the destruction of the crystals. The significant dissolution following the destruction of the crystals led to the rounding of the vertices and edges of their fragments. Apparently, most of the very elongated crystals from placers with unknown sources are also highly dissolved isometric crystal fragments. The obtained results have shown that the deformation and dissolution of diamond crystals are related events characteristic of diamonds from hitherto undetected, but highly productive primary deposits.
DS202104-0582
2020
Vasilev, E.A.Klepikov, I.V., Vasilev, E.A., Antonov, A.V.The defect impurity composition of diamond crystals with ( 100) growth pyramids from placers of the Krasnovishersk district, the Urals.Geology of Ore Deposits, Vol. 62, 8, pp. 743-753. pdfRussia, Uralscuboid diamonds

Abstract: The internal structure and spectroscopic features of cuboid diamonds from recent alluvial placers of the Krasnovishersk District (the Urals) have been investigated. Crystals were divided into four groups by their anatomy and spectroscopy: cuboids of the II group (according to the Yu.L. Orlov classification): cuboids with a transparent core and peripheral zone saturated with inclusions; crystals with mixed habit growth of ?100? and ?111? pyramids, and crystals with the sequential growth of ?100? and ?111? pyramids. In all studied crystals, the regenerative formation of the {111} face steps together with the formation of tetragonal pits on the cuboid surface was the last stage of growth. Local photoluminescence investigations have been carried out for all cubic diamond crystals of the Urals for the first time. It was established that luminescence bands at 926 and 933 nm are related to growth pyramids of ?100? and ?111?, respectively. Bands with peaks at 800, 820.5, 840, 860, and 869 nm were revealed in the luminescence systems of the cuboids of II group. We note that the cuboid diamonds from different regions of the world have similar internal structures and spectroscopic features.
DS202204-0541
2022
Vasilev, E.A.Vasilev, E.A., Kriulina, G.Yu., Garanin, V.K.Spectroscopy of diamond from the M.V. Lomonosov deposit.Geology of Ore Deposits, Vol. 63, 7, pp. 668-674.Russia, Kola Peninsuladeposit - Lomonosov

Abstract: Diamond crystals from the M.V. Lomonosov deposit (Archangelsk oblast, Russia) were studied by luminescence and infrared spectroscopy. Three groups of crystals were distinguished according to their morphology, thermal history, and photoluminescence. The structural diversity of yellow cuboids typical for the deposit is demonstrated. New photoluminescence systems among the low-temperature cuboid crystals are observed.
DS201312-0545
2012
Vasilev, P.Litvin, Yu., Vasilev, P., Bobrov, A., Okoemova, V., Kuzyura, A.Parental media of natural diamonds and primary mineral inclusions in them: evidence from physicochemical experiment.Geochemistry International, Vol. 50, 9, pp. 726-759.TechnologyDiamonds inclusions
DS201412-0494
2014
Vasilev, P.G.Kuzyura, A.V., Litvin, Yu.A., Vasilev, P.G., Jeffries, T., Wall, F.Partitioning of rare elements between diamond forming melts and minerals of the peridotite-carbonatite system.Doklady Earth Sciences, Vol. 455, 2, pp. 419-424.TechnologyPhysicochemical experiments
DS1960-0195
1961
Vasilev, V.G.Vasilev, V.G., Kovalskii, V.V., Cherskii, N.V.Problema Proiskhozhdeniya AlmazovYakutsk: Yakutskoe Knizhnoc Izdat., 152P.RussiaKimberlite, Diamond, Genesis, Kimberley
DS1995-0060
1995
Vasilev, Y.Arndt, N., Lehert, K., Vasilev, Y.Meimechites: highly magnesian lithosphere contaminated alkaline magmas from deep subcontinental mantle.Lithos, Vol. 34, No. 1-3, Jan. pp. 41-60.MantleMeimechites, Alkaline rocks
DS1998-1523
1998
Vasilev, Y.R.Vasilev, Y.R., Zolotukhin, V.V., Laguta, O.N.Shoshonites of the Northern Siberian PlatformDoklady Academy of Sciences, Vol. 361A, No. 6, pp. 799-03.Russia, SiberiaMagmatism, Shoshonites
DS2002-1798
2002
Vasilev, Y.R.Zolotukhin, V.V., Vasilev, Y.R.Distinctive genetic features of K rich basitesPetrology, Vol.10, 1, pp. 78-97.Russia, SiberiaMantle metasomatism
DS200712-1111
2007
Vasilev, Y.R.Vasilev, Y.R., Prusskaya, S.N., Mazurov, M.P.A new type of large scale manifestation of within plate intrusive trap magmatism.Doklady Earth Sciences, Vol. 413, 2, pp. 187-191.RussiaMagmatism
DS1987-0835
1987
Vasilev, Yu.R.Zolotukhin, V.V., Vasilev, Yu.R.inter relations of ultrabasic, basic and alkaline basic platform SOURCE[ Soviet Geology and GeophysicsSoviet Geology and Geophysics, Vol. 28, No. 1, pp. 35-44RussiaAlkaline rocks
DS1987-0836
1987
Vasilev, Yu.R.Zolotukhin, V.V., Vasilev, Yu.R.inter relations of ultrabasitic, basitic and alkaline basitic platform magmatism ( as exemplified by the Siberian platform).RUS*Geol. Geof.(Russian), No. 1, January pp. ?RussiaBlank
DS201212-0752
2012
Vasilev, Yu.R.Vasilev, Yu.R.,Gora, M.P.The origin of dunites and olivinites in the alkali-ultrabasic intrusive complexes of the Siberian craton.Doklady Earth Sciences, Vol. 442, 1, pp.36-39.Russia, SiberiaAlkalic
DS201412-0942
2014
Vasilev, Yu.R.Vasilev, Yu.R., Gora, M.P.Meimechite-picrite associations in Siberia, Primorye, and Kamchatka ( comparitive analysis and petrogenesis).Russian Geology and Geophysics, Vol. 55, 8, pp. 959-970.RussiaMeimechite
DS201412-0943
2014
Vasilev, Yu.R.Vasilev, Yu.R., Gora, M.P.Meimechite-picrite associations in Siberia, Primorye and Kamchatka ( compartive analysis and petrogenesis).Russian Geology and Geophysics, Vol 55, pp. 959-970.Russia, SiberiaMeimechite, picrite
DS201608-1448
2016
Vasilev, Yu.R.Vasilev, Yu.R., Gora, M.P.Nature of voluminous meimechite picrite associations in Siberia and other regions.Doklady Earth Sciences, Vol. 468, 1, pp. 469-472.RussiaMeimechite, picrite

Abstract: Analysis of petrochemical and geochemical information of the same levels, which characterize rocks and primary melt inclusions in olivines of heterochronic meimechite-picrite associations in Siberia (Maimecha-Kotui province), Primorye (Sikhote-Alin), and Kamchatka demonstrated that, besides the similar appearance and identical structural patterns, they are considerably discrepant in the concentration and distribution of incompatible and rare earth elements. Those differences are also observed for the compositions and evolutionary trends of parental high-temperature magnesium-rich melts. This, in turn, was assumed to be a consequence of a variable degree of melting of the mantle protoliths in the mentioned regions, which is supported by geochemical modeling.
DS201707-1379
2017
Vasilev, Yu.R.Vasilev, Yu.R., Gora, M.P., Kuzmin, D.V.Petrology of foiditic and meymechitic volcanism in the Maimecha - Kotui province ( Polar Siberia).Russian Geology and Geophysics, Vol. 58, pp. 659-673.Russia, Siberiaalkaline - Maimecha

Abstract: Comparative analysis of ultramafic meymechites of the Maimecha Suite and alkaline volcanics of the Ary-Dzhang Suite (foidites (nephelinites, analcimites, limburgites, etc.) and melilitites) has shown their consanguinity, which indicates their relationship with the same magmatic system periodically producing large amounts of alkaline ultramafic melts. We have studied the petrogeochemical and mineralogical compositions of rocks and melt inclusions in the hosted olivines. The rocks of the Maimecha and Ary-Dzhang Suite differ considerably in MgO content, which is well explained by the accumulation of olivine. The inclusions in olivines from the meymechites and the rocks of the Ary-Dzhang Suite correspond in composition to foidites. The trace and rare-earth element patterns are similar both in the foidites and meymechites and in the melt inclusions: They show negative anomalies of Rb and K and positive anomalies of Nb and Ta. The ratios of indicator elements (Nb/Ta, Ba/La, Ta/La, etc.) in the rocks of the Maimecha and Ary-Dzhang Suite are constant and almost independent of their Mg# values. The La/Yb ratio in the foidites is significantly higher than that in the meymechites and in the melt inclusions from their olivines, which indicates that the rocks of the Ary-Dzhang Suite resulted from the fractionation of highly magnesian alkaline picritoid melt.
DS201804-0750
2018
Vasilev, Yu.R.Vasilev, Yu.R., Gora, M.P., Kuzmin, D.V.Foidite and meimechite lavas of Polar Siberia ( some questions of petrogenesis.Doklady Earth Sciences, Vol. 478, 1, pp. 103-107.Russia, Siberiapicrites

Abstract: For the Permian-Triassic foidite and meimechite lavas of Polar Siberia, both the whole-rock petrochemistry and geochemistry and that of melt inclusions in olivine phenocrysts from the same rocks have been demonstrated to be similar. In addition, their isotope characteristics imply the possibility of their generation from an abyssal parental melt compositionally resembling a high-Mg alkaline picrite.
DS201602-0249
2015
Vasileva, T.I.Zayakina, N.V., Oleinikov, O.B., Vasileva, T.I., Oparin, N.A.Coalingite from kimberlite breccia of the Manchary pipe, central Yakutia.Geology of Ore Deposits, Vol. 57, 8, pp. 732-736.Russia, YakutiaDeposit - Manchary

Abstract: Coalingite, Mg10Fe2(CO3)(OH)24 • 2H2O, rare Mg -Fe hydrous carbonate, has been found in the course of the mineralogical study of a disintegrated kimberlite breccia from the Manchary pipe of the Khompu -May field located in the Tamma Basin, Central Yakutia, 100 km south of Yakutsk. Coalingite occurs as small reddish brown platelets, up to 0.2 mm in size. It is associated with lizardite, chrysotile and brucite, which are typical kimberlitic assemblage. Coalingite is a supergene mineral, but in this case, it is produced by the interaction of brucite-bearing kimberlite and underground water circulating through a vertical or oblique fault zone.
DS1988-0737
1988
Vasilevskii, A.N.Vitte, L.V., Vasilevskii, A.N.The question of tectonic position and forms of manifestations of alkaline ultrabasic magmatism In the crust of the Siberian PlatformSoviet Geology and Geophysics, Vol. 29, No. 5, pp. 46-54RussiaAlkaline rocks, Tectonics
DS1999-0750
1999
Vasilevskii, A.N.Tychkov, S.A., Rychkova, E.V., Vasilevskii, A.N.Interaction between a plume and thermal convection in the continental uppermantle.Russian Geology and Geophysics, Vol. 39, No. 4, pp. 423-34.MantlePlume, hotspots, Geothermometry
DS1999-0751
1999
Vasilevskii, A.N.Tychkov, S.A., Vasilevskii, A.N., Rychkova, E.V.Evolution of plume beneath continental lithosphere of variable thicknessRussian Geology and Geophysics, Vol. 40, No. 8, pp. 1163-76.MantlePlumes, Lithosphere
DS201606-1125
2005
Vasiley, E.A.Vasiley, E.A., Ivanov-Omskii, V.I., Bogush, I.N.Institial carbon showing up in the absorption spectra of natural diamonds. Technical Physics ** in ENG, Vol. 50, 6, pp. 711-714.TechnologyNitrogen

Abstract: Natural diamonds are studied by Fourier-transform IR (FTIR) spectroscopy, and it is shown that B2 centers in them form through intermediate stages, which are accompanied by the appearance of absorption bands with maxima near 1550 and 1526 cm?1. The concentration of interstitial carbon atoms in the centers responsible for these bands may be several times higher than the concentration of the interstitials in B 2 defects.
DS1983-0615
1983
Vasileyev, L.A.Vasileyev, L.A., Belykh, Z.P.Diamonds; their Properties and Use.(russian)Izd. Nedra, Moscow, Ussr, (russian), 101pRussiaDiamond, Diamond Morphology
DS201709-1957
2017
Vasileyev, P.Aulbach, S., Woodland, A.B., Vasileyev, P., Galvez, M.E., Viljoen, K.S.Effects of low pressure igneous processes and subduction on Fe3/Fe and redox state of mantle eclogites from Lace ( Kaapvaal craton).Earth and Planetary Science Letters, Vol. 474, pp. 283-295.Africa, South Africadeposit - Lace

Abstract: Reconstructing the redox state of the mantle is critical in discussing the evolution of atmospheric composition through time. Kimberlite-borne mantle eclogite xenoliths, commonly interpreted as representing former oceanic crust, may record the chemical and physical state of Archaean and Proterozoic convecting mantle sources that generated their magmatic protoliths. However, their message is generally obscured by a range of primary (igneous differentiation) and secondary processes (seawater alteration, metamorphism, metasomatism). Here, we report the Fe3+/?Fe ratio and ?18 O in garnet from in a suite of well-characterised mantle eclogite and pyroxenite xenoliths hosted in the Lace kimberlite (Kaapvaal craton), which originated as ca. 3 Ga-old ocean floor. Fe3+/?Fe in garnet (0.01 to 0.063, median 0.02; n = 16) shows a negative correlation with jadeite content in clinopyroxene, suggesting increased partitioning of Fe3+ into clinopyroxene in the presence of monovalent cations with which it can form coupled substitutions. Jadeite-corrected Fe3+/?Fe in garnet shows a broad negative trend with Eu*, consistent with incompatible behaviour of Fe3+ during olivine-plagioclase accumulation in the protoliths. This trend is partially obscured by increasing Fe3+ partitioning into garnet along a conductive cratonic geotherm. In contrast, NMORB-normalised Nd/Yb - a proxy of partial melt loss from subducting oceanic crust (<1) and metasomatism by LREE-enriched liquids (>1) - shows no obvious correlation with Fe3+/?Fe, nor does garnet ?18OVSMOW (5.14 to 6.21‰) point to significant seawater alteration. Median bulk-rock Fe3+/?Fe is roughly estimated at 0.025. This observation agrees with V/Sc systematics, which collectively point to a reduced Archaean convecting mantle source to the igneous protoliths of these eclogites compared to the modern MORB source. Oxygen fugacites (fO2) relative to the fayalite-magnetite-quartz buffer (FMQ) range from ?log ? fO2 = FMQ-1.3 to FMQ-4.6. At those reducing conditions, the solubility of carbon in the fluids released by dehydration is higher than in fluids closer to FMQ. The implication is that Archean processes of C transport and deposition would have differed from those known in modern-style subduction zones, and diamond would have formed from methane-rich fluids. In addition, such reducing material could drive redox melting or freezing upon deep recycling and migration of CH4-bearing fluids into the ambient mantle.
DS202008-1368
2019
Vasileyev, P.Aulbach, S., Woodand, A.B., Stern, R.A., Vasileyev, P., Heaman, L.M., Viljoen, K.S.Evidence for a dominantly reducing Archean ambient mantle from two redox proxies, and low oxygen fugacity of deeply subducted oceanic crust. Nature Research Scientific Reports, Vol. 9:20190 doir.org/10.38 /s41598-019-55743-1, 11p. PdfMantleeclogite

Abstract: Oxygen fugacity (ƒO2) is an intensive variable implicated in a range of processes that have shaped the Earth system, but there is controversy on the timing and rate of oxidation of the uppermost convecting mantle to its present ƒO2 around the fayalite-magnetite-quartz oxygen buffer. Here, we report Fe3+/?Fe and ƒO2 for ancient eclogite xenoliths with oceanic crustal protoliths that sampled the coeval ambient convecting mantle. Using new and published data, we demonstrate that in these eclogites, two redox proxies, V/Sc and Fe3+/?Fe, behave sympathetically, despite different responses of their protoliths to differentiation and post-formation degassing, seawater alteration, devolatilisation and partial melting, testifying to an unexpected robustness of Fe3+/?Fe. Therefore, these processes, while causing significant scatter, did not completely obliterate the underlying convecting mantle signal. Considering only unmetasomatised samples with non-cumulate and little-differentiated protoliths, V/Sc and Fe3+/?Fe in two Archaean eclogite suites are significantly lower than those of modern mid-ocean ridge basalts (MORB), while a third suite has ratios similar to modern MORB, indicating redox heterogeneity. Another major finding is the predominantly low though variable estimated ƒO2 of eclogite at mantle depths, which does not permit stabilisation of CO2-dominated fluids or pure carbonatite melts. Conversely, low-ƒO2 eclogite may have caused efficient reduction of CO2 in fluids and melts generated in other portions of ancient subducting slabs, consistent with eclogitic diamond formation ages, the disproportionate frequency of eclogitic diamonds relative to the subordinate abundance of eclogite in the mantle lithosphere and the general absence of carbonate in mantle eclogite. This indicates carbon recycling at least to depths of diamond stability and may have represented a significant pathway for carbon ingassing through time.
DS1995-1083
1995
Vasiliev, A.A.Lelukh, M.I., Vasiliev, A.A., Kryuchkov, A.I., Cherny, S.D.New dat a on morphology of kimberlite bodiesProceedings of the Sixth International Kimberlite Conference Almazy Rossii Sakha abstract, p. 10, 11.Russia, YakutiaStructure - pipe, Deposit -Rot Front, Yakutskaya
DS201904-0792
2019
Vasiliev, E.Vasiliev, E.Hydrogen in diamond and a thermal history of diamond crystals.researchgate.net, https://www.researchgate.net/ publication/330360071Russiadiamond morphology

Abstract: We have performed an analysis of the cases of synchronism in th egrowth temperature in local zones of diamond crystals and the concentration of hydrogen in them.The considered cases were observed by the authors and fined out in the iterature. Possible causes of the simbatic change in the crystal growth temperature and the concentration of hydrogen in it are considered.The determination of the temperature change over the zones was carried out on the basis of local FTIR spectroscopy from the ratio of the nitrogen concentration in the form of defects in the crystal structure of A and B1, and size the B2 defects.The change in the hydrogen concentration in various zones of diamond crystals was estimated from the 3107cm-1 band of the hydrogen-containing defect. It is shown that in the analyzed cases the concentration of hydrogen in diamond is determined mainly by its content in the growth medium.We accept the obtained results as evidence of the participation of hydrogen in the heat transfer in mantle mineral-forming systems.
DS201904-0793
2019
Vasiliev, E.Vasiliev, E., Klepikov, I., Antonov, A.V.Rounded diamond crystals with mixed growth mechanism from alluvial placers of the Krasnovishersky district.researchgate.net, https://www.researchgate.net/ publication/328305567Russiadiamond morphology
DS201605-0883
2015
Vasiliev, E.A.Petrovsky, V.A., Silaev, V.I., Sukharev, A.E., Golubeva, I.I., Rakin, V.I., Lutoev, V.P., Vasiliev, E.A.Placer forming Diamondiferous rocks and diamonds of Eastern Brazil. IN RUSS Eng. Abs.Thesis, Vestnik Permskogo Universitecta IN RUSS, Vol. 1, 30, pp. 33-59.South America, BrazilAlluvials
DS201805-0987
2017
Vasiliev, E.A.Vasiliev, E.A., Petrovsky, V.A., Kozlov, A.V., Antonov, A.V.Infrared spectroscope and internal structure of diamonds from the Ichhetju placer ( Middle Timan, Russia).*** IN RUSProceedings of the Russian Mineralogical Society *** IN RUS, Vol. 146, 2, pp. 58-72.Russiadeposit - Ichhetju
DS201904-0794
2018
Vasiliev, E.A.Vasiliev, E.A., Petrovsky, V.A., Kozlov, A.V., Antonov, A.V.Infrared spectroscopy and internal structure of diamonds from the Ichetyu placer, central Timan, Russia.Geology of Ore Deposits, Vol. 60, 7, pp. 616-624.Russia, Uralsdiamond morphology

Abstract: A wide range of model temperature, which is typical for dodecahedroids from placer deposits in the Urals, Brazil, and the northern Yakutia diamond province has been identified in diamond crystals of the Ichetyu Ural-type diamonds deposit, Central Urals. Plates were cut from six crystals; it have been studied with cathodoluminescence and infrared and photoluminescence spectroscopy. Octahedral zoning predominates in the internal structure of rounded dodecahedroids, and growth layers are cut by the surface. Surface pigmentation spots are exhibited in the cathodoluminescent images of all plates. The nitrogen concentration in Ichetyu diamonds ranges from 100 to 2200 ppm and its proportion as B1 defects varies from 0 to 100%. The maximum absorption coefficient of hydrogen band is 56 cm-1 with an average value of 0.8 cm-1.
DS201906-1357
2018
Vasiliev, E.A.Vasiliev, E.A., Klepikov, I.V., Antonov, A.V.Rounded diamond crystals with mixed growth mechanism from alluvial placers of the Krasnovishersky district, the Urals. Abstract only in ENGProceedings of the Russian Mineralogical Society , Pt CXLVII no. 4, 14p.Russiadiamond morphology
DS201909-2054
2019
Vasiliev, E.A.Kriulina, G.Yu., Vasiliev, E.A., Garanin, V.K.Structural and mineralogical features of diamonds from the Lomonosov deposit ( Arkhangelsk Province): new data and interpretation.Doklady Earth Sciences, Vol. 486, 2, pp. 627-629.Russia, Archangeldeposit - Lomonosov

Abstract: Three groups of diamond crystals that differ in morphology, photoluminescence, infrared absorption, and thermal history were discovered in the Lomonosov deposit. The first group crystals are mostly octahedrons with minor signs of dissolution and a large share of nitrogen in the form of B defects. The crystals of the second type are strongly resorbed dodecahedroids with a small share of B defects. The third group consists of crystals with low-temperature ? defects; they are cuboids that are often without traces of resorption, and tetrahexahedroids. These patterns indicate the polygenicity of the diamond in the Lomonosov deposit.
DS202110-1634
2021
Vasiliev, E.A.Proskumin, V.F., Grakhanov, S.A., Petrov, O.V., Vasiliev, E.A., Berzon, E.I., Antonov, A.V., Sobolev, N.V.Forecast of the diamond potential of Taimyr.Doklady Earth Sciences, Vol. 499, 2, pp. 611-615.Russiadeposit - Taimyr

Abstract: Although irrefutable evidence for the presence of signs of diamondiferous kimberlite on the Taimyr Peninsula were obtained in the 1930s, it was only in 2020 that a macrodiamond (>1 mm) was first discovered in Eastern Taimyr. This was a colorless laminar crystal of a transitional shape from an octahedron to a rhombododecahedron. According to the set of features, the crystal is rare and atypical of the known primary and alluvial deposits of the Siberian Diamond Province. The find of this diamond indicates the presence of primary sources and the need for medium-scale geological survey and exploration over a large area from Anabar Bay (Pronchishchev Ridge) to the west to the Kiryaka-Tas and Tulai-Kiryaka highlands and to the northeast to Tsvetkov Cape.
DS200612-0203
2006
Vasiliev, M.V.Bychkova, Ya.V., Kulikov, V.S., Kulikova, V.V., Vasiliev, M.V.Early Paleoproterozoic vulcano-plutonic komatiitic association of southeast Fennoscandia as mantle plume 'windybelt' realization.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 174-187.Europe, Finland, Sweden, Baltic Shield, FennoscandiaHotspots
DS201012-0815
2010
Vasiliev, P.Vasiliev, P., Okoemova, V., Litvin, Y., Bobrov, A.Experimental study of syngenetic relations of diamond and its inclusions in the heterogeneous system eclogite carbonatite sulfide diamond at 7.0 GPa.International Mineralogical Association meeting August Budapest, abstract p. 179.TechnologyDiamond genesis
DS201112-0610
2011
Vasiliev, P.G.Litvin, Yu.A., Vasiliev, P.G., Bobrov, A.V., Okoyomova, V.Yu., Kuzyura, A.V.Parental media for diamonds and primary inclusions by evidence of physicochemical experiment.Vestnik ONZ RAN *** in english, 4p. IN ENGLISHMantleMantle melting - carbonatite genesis of diamond
DS201112-0755
2011
Vasiliev, P.G.Okoemova, V.Yu., Vasiliev, P.G., Kuzyura, A.V., Litvin, Yu.A., Wall, F., Jeffries, T.Experimental study of partition of rare elements between minerals and melts of diamond forming eclogite carbonatite and peridotite carbonatites systems.Goldschmidt Conference 2011, abstract p.1566.TechnologyHP
DS1994-1073
1994
Vasiliev, V.V.Luzin, G.P., Pretes, M., Vasiliev, V.V.The Kola Peninsula: geography, history and resourcesArctic, Vol. 47, No. 1, March pp. 1-15.Russia, Kola PeninsulaHistory, Resources
DS1996-1471
1996
Vasiliev, Y.R.Vasiliev, Y.R., Zolotukhin, V.V.The Maimecha Kotui alkaline ultramafic province of the northern Siberianplatform, Russia.Episodes, Vol. 18, No. 4, pp. 155-158.RussiaAlkaline rocks, Deposit -Maimecha Kotui
DS201804-0737
2017
Vasiliev, Yu.R.Simonov, V.A., Prikhodko, V.S., Vasiliev, Yu.R., Kotlyarov, A.V.Physicochemical conditions of the crystallization of rocks from ultrabasic massifs of the Siberian platform. Konder, Inagli, Chad) Cr-spinelsRussian Journal of Pacific Geology, Vol. 11, 6, pp. 447-468.Russiapicrites

Abstract: A great volume of original information on the formation of the ultrabasic rocks of the Siberian Platform has been accumulated owing to the study of melt inclusions in Cr-spinels. The inclusions show the general tendencies in the behavior of the magmatic systems during the formation of the ultrabasic massifs of the Siberian Platform, tracing the main evolution trend of decreasing Mg number with SiO2 increase in the melts with subsequent transition from picrites through picrobasalts to basalts. The compositions of the melt inclusions indicate that the crystallization conditions of the rocks of the concentrically zoned massifs (Konder, Inagli, Chad) sharply differ from those of the Guli massif. Numerical modeling using the PETROLOG and PLUTON softwares and data on the composition of inclusions in Cr-spinels yielded maximum crystallization temperatures of the olivines from the dunites of the Konder (1545-1430°C), Inagli (1530-1430°C), Chad (1460-1420°C), and Guli (1520-1420°C) massifs, and those of Cr-spinels from the Konder (1420-1380°C), Inagli (up to 1430°C), Chad (1430-1330°C), and Guli (1410-1370°C) massifs. Modeling of the Guli massif with the PLUTON software using the compositions of the melt inclusions revealed the possible formation of the alkaline rocks at the final reverse stage of the evolution of the picritic magmas (with decrease of SiO2 and alkali accumulation) after termination of olivine crystallization with temperature decrease from 1240-1230°C to 1200-1090°C. Modeling with the PLUTON software showed that the dunites of the Guli massif coexisted with Fe-rich (with moderate TiO2 contents) melts, the crystallization of which led (beginning from 1210°C) to the formation of pyroxenes between cumulate olivine. Further temperature decrease (from 1125°C) with decreasing FeO and TiO2 contents provided the formation of clinopyroxenes of pyroxenites. For the Konder massif, modeling with the PLUTON software indicates the possible formation of kosvites from picrobasaltic magmas beginning from 1350°C and the formation of clinopyroxenites and olivine-diopside rocks from olivine basaltic melts from 1250°C.
DS1990-0258
1990
Vasiljeva, E.R.Busheva, E.B., Vasiljeva, E.R., Garanin, V.K., KudrjavtsevaMineralogy of kimberlites of the northern European part of the USSRInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 786-788RussiaKimberlites, Mineralogy
DS1991-0936
1991
Vasiljeva, E.R.Kudrjavtseva, G.P., Bushueva, E.B., Vasiljeva, E.R., Verichev, E.M.Geological structure and mineralogy of the kimberlites of the Archangelsk kimberlite provinceProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 530-532RussiaDiatremes, Structure
DS201212-0381
2012
Vasillev, E.A.Kriulina, G.Y., Kyazimov, V.O., Vasillev, E.A., Matveeva, O.P.New dat a on the structure of the cubic habit diamonds from the M.V. Lomonosov diamond deposit. Archangelsk Diamondiferous Province, Russia.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractRussia, Archangel, Kola PeninsulaDeposit - Lomonosov
DS201907-1555
2019
Vasilukov, D.M.Kupenko, G.A., Vasilukov, D.M., McCammon, C., Charleton, S., Cerantola, V., Kantor, I., Chumakov, A.I.., Ruffer, R., Dubrovinsky, L, Sanchez-Valle, C.Magnetism in cold subducting slabs at mantle transition zone depths.Nature, Vol. 570, 7759, p. 102.Mantlesubduction

Abstract: The Earth’s crust-mantle boundary, the Mohorovi?i? discontinuity, has been traditionally considered to be the interface between the magnetic crust and the non-magnetic mantle1. However, this assumption has been questioned by geophysical observations2,3 and by the identification of magnetic remanence in mantle xenoliths4, which suggest mantle magnetic sources. Owing to their high critical temperatures, iron oxides are the only potential sources of magnetic anomalies at mantle depths5. Haematite (?-Fe2O3) is the dominant iron oxide in subducted lithologies at depths of 300 to 600 kilometres, delineated by the thermal decomposition of magnetite and the crystallization of a high-pressure magnetite phase deeper than about 600 kilometres6. The lack of data on the magnetic properties of haematite at relevant pressure-temperature conditions, however, hinders the identification of magnetic boundaries within the mantle and their contribution to observed magnetic anomalies. Here we apply synchrotron Mössbauer source spectroscopy in laser-heated diamond anvil cells to investigate the magnetic transitions and critical temperatures in Fe2O3 polymorphs7 at pressures and temperatures of up to 90 gigapascals and 1,300 kelvin, respectively. Our results show that haematite remains magnetic at the depth of the transition zone in the Earth’s mantle in cold or very cold subduction geotherms, forming a frame of deep magnetized rocks in the West Pacific region. The deep magnetic sources spatially correlate with preferred paths of the Earth’s virtual geomagnetic poles during reversals8 that might not reflect the geometry of the transitional field. Rather, the paths might be an artefact caused by magnetized haematite-bearing rocks in cold subducting slabs at mid-transition zone depths. Such deep sources should be taken into account when carrying out inversions of the Earth’s geomagnetic data9, and especially in studies of planetary bodies that no longer have a dynamo10, such as Mars.
DS201412-0566
2013
Vasily, P.McCammon, C., Glazyrin, K., Kantor, A., Kantor, I., Kupenko, I., Narygina, O., Potapin, V., Vasily, P., Sinmyo, C., Chumakov, Ruffer, Sergueev, Smirnov, DubrovinskyIron spin state in silicate perovskite at conditions of Earth's deep interior.International Journal of High Pressure Research, Vol. 33, 3, pp. 663-672.MantlePerovskite
DS201112-1082
2011
Vasilyev, E.Vasilyev, E.The nature of black coloration in gem quality diamonds.GIA International Symposium 2011, Gems & Gemology, Summer poster abstract p. 135.TechnologyDiamond color
DS201412-0683
2014
Vasilyev, E.A.Petrovsky, V.A., Silaev, V.I., Sukharev, A.E., Vasilyev, E.A., Pomazansky, B.S., Zemnukhov, A.L.Yakutites: mineralogical geochemical properties and new version of the genesis. Part 1.Izvestiya VUZ'ov Geologia I Razvedka ** in Russia Courtesy of Felix, No. 3, pp. 24-33.Russia, YakutiaCarbonado, with lonsdaleite
DS201412-0944
2014
Vasilyev, P.Vasilyev, P., Yaxley, G., Hermann, J., O'Neill, H., Berry, A.Experimental investigation of the effect of oxygen fugacity on diamond versus carbonate in carbon-bearing eclogites during deep subduction.Goldschmidt Conference 2014, 1p. AbstractMantleSubduction
DS202002-0161
2019
Vasilyev, P.Aulbach, S., Woodland, A.B., Stern, R.A., Vasilyev, P., Heaman, L.M., Viljoen, K.S.Evidence for a dominantly reducing Archaean ambient mantle from two redox proxies, and low oxygen fugacity of deeply subducted oceanic crust.Nature Research Scientific Reports, https://doi.org/10.1038/ s41598-019-55743-1 11p. PdfMantlemelting, redox

Abstract: Privacy Policy. You can manage your preferences in 'Manage Cookies'. Oxygen fugacity (fO2) is an intensive variable implicated in a range of processes that have shaped the Earth system, but there is controversy on the timing and rate of oxidation of the uppermost convecting mantle to its present fO2 around the fayalite-magnetite-quartz oxygen buffer. Here, we report Fe3+/?Fe and ƒf2 for ancient eclogite xenoliths with oceanic crustal protoliths that sampled the coeval ambient convecting mantle. Using new and published data, we demonstrate that in these eclogites, two redox proxies, V/Sc and Fe3+/?Fe, behave sympathetically, despite different responses of their protoliths to differentiation and post-formation degassing, seawater alteration, devolatilisation and partial melting, testifying to an unexpected robustness of Fe3+/?Fe. Therefore, these processes, while causing significant scatter, did not completely obliterate the underlying convecting mantle signal. Considering only unmetasomatised samples with non-cumulate and little-differentiated protoliths, V/Sc and Fe3+/?Fe in two Archaean eclogite suites are significantly lower than those of modern mid-ocean ridge basalts (MORB), while a third suite has ratios similar to modern MORB, indicating redox heterogeneity. Another major finding is the predominantly low though variable estimated fO2 of eclogite at mantle depths, which does not permit stabilisation of CO2-dominated fluids or pure carbonatite melts. Conversely, low-fO2 eclogite may have caused efficient reduction of CO2 in fluids and melts generated in other portions of ancient subducting slabs, consistent with eclogitic diamond formation ages, the disproportionate frequency of eclogitic diamonds relative to the subordinate abundance of eclogite in the mantle lithosphere and the general absence of carbonate in mantle eclogite. This indicates carbon recycling at least to depths of diamond stability and may have represented a significant pathway for carbon ingassing through time.
DS202008-1455
2020
Vasilyev, P.Vasilyev, P., McInnes, B., Reddicliffe, T.Evaluation of the source of diamonds and other kimberlitic minerals from the Webb kimberlite field, western Australia.Goldschmidt 2020, 1p. AbstractAustralia, Western Australiadeposit - Webb

Abstract: play located ~600 km west of Alice Springs in a remote region of WA. Exploration by GeoCrystal Ltd has identified more than 280 ‘bulls-eye’ magnetic features over a ~400 km2 area. Reconnaissance drilling of some of these features has returned mineral samples of kimberlite affinity, while surface sampling has recovered detrital microdiamonds with the number of inclusions, later analysed with FIBSEM. The unaltered diamond indicator minerals from drill samples analysed include: (i) G9 garnet predominating over G10; (ii) olivine ranging from Fo84-Fo91; (iii) Crdiopside (0.8-1.8% Cr2O3) and (iv) a broad range of Cr-Al spinel. A thermobarometric assessments of mineral chemistry data [1-3] show good agreement with each other and indicate a mantle origin for number of northern targets, including ones at possible equilibrium within the diamond stability field (P=45-50 kbar; T=1150- 1170°C). These results contain important information about the understudied deep lithosphere of Central Australia region.
DS201312-0938
2013
Vasilyev, V.Vasilyev, V., Yaxley, G., Hermann, J., O'Neill, H.Phase relations of carbonate eclogite during subduction and the effect of redox conditions on diamond - carbonate reactions.Goldschmidt 2013, 1p. AbstractTechnologyEclogite
DS1970-0440
1971
Vasilyev, V.G.Vasilyev, V.G.Origin of Diamonds (1971)International Geology Review, Vol. 13, No. 1, PP. 60-61.RussiaBook Review, Genesis
DS202102-0178
2020
Vasilyev, Y.Chayka, I., Kamenetsky, V.S., Vasilyev, Y., Prokopyev, I.R.Spinel-group minerals in peridotites of the Guli and Bor-Uryakh intrusions ( Meimecha-Kotuy Province, northern Siberia).SGEM Conference 20th., doi:10.5593/ sgem2020/1.1. /s01.038Russia, Siberiaperidotites

Abstract: The Guli and Bor-Uryakh massifs, a part of the Siberian Large igneous province (LIP) are mafic-ultramafic intrusive complexes, withstrongalkaline affinity. They contain deposits of apatite and arealsoknown to be source rocks ofOs-Ir-Ruplacers.These massifs are of great interest for petrologists worldwide, as they are composed of an unusual variety of rocks (dunites/olivinites, shonkinites, melilitites, alkali syenites and carbonatites) and being coeval with Siberian trap volcanic rocks, includingdiamondiferous kimberlites. Since mineralogical approaches based on spinel-group minerals have been proved to be efficient in constraining origin of the ultramafics, we present the first descriptive study of chromite and magnetite mineralization, observed in olivine-dominated rocks of the Guli and Bor-Uryakh intrusions. In dunites of Guli massif spinel-group minerals are dominated by Mg-poor chromite (FeMg)Cr2O4and Cr-Ti-rich magnetiteFeFe2O4, while in Bor-Uryakh massif spinel-group minerals are predominantly magnetite with only minor Mg-poor chromite.These minerals form either small euhedral inclusions in olivine or largesubhedral to anhedral grains in serpentinized fractures and interstitial space. The lattertype of grainscan have intricated irregular shapeand contain inclusions. We also observed abundant Cr-magnetite lamellae in olivine and chromite/magnetite micro-grains within olivine-hosted multiphase inclusions.Spinel (MgAl2O4) is occasionally found in intergrowths with chromite and magnetite.The obtained data show that spinel-group minerals in the massifsdo not correspond to primary-magmatic varieties and suggestextensive alteration during post-magmatic processes. Textural and chemical evidenceof substantial modification of initially-cumulative lithologies of Guli and Bor-Uryakh massifsfavorsmeta-magmatic origin for these massifs.
DS1988-0726
1988
Vasilyev, Yu.R.Vasilyev, Yu.R.Feldspathic picrites of the Ayan riverSoviet Geology and Geophysics, Vol. 29, No. 4, pp. 63-69RussiaPicrites
DS1996-1472
1996
Vasilyeva, E.R.Vasilyeva, E.R., Garanin, V.K., Kadryavtseva, G.P.Mineralogy of garnets from kimberlites of Arkangelsk diamond bearingprovince.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 386.RussiaGarnet mineralogy, Kimberlites
DS1998-0469
1998
Vasilyeva, E.R.Garanin, V.K., Kudriavtseva, G.P., Vasilyeva, E.R.The fundamental study of garnets: application for prospecting and economical estimation - diamond bearing7th International Kimberlite Conference Abstract, pp. 236-8.Russia, Arkangelsk, Kola PeninsulaGarnet mineralogy, Deposit - Zolitsky, Verkhotinsky
DS1975-0425
1976
Vasilyeva, N.V.Vasilyeva, N.V.Features of the Inner Structure of Marcasite from the Kimberlite Pipe "udachnaya".Vyssh. Uchebn. Zaved. Izv. Geol. Razved., 1976, No. 12, PP. 155-156.RussiaBlank
DS1975-0426
1976
Vasilyeva, Z.V.Vasilyeva, Z.V., Rudnitskaya, YE. S.A Study of Natural Carbonate Bearing Apatites Using Infrared Spectroscopy.Akad. Nauk. Sssr Izv. Ser. Geol., Vol. 1976, No. 9, PP. 103-111.RussiaKimberlite
DS201709-2014
2017
Vasiukov, D.M.Kiseeva, E.S., Vasiukov, D.M., Wood, B.J., McCammon, C., Stachel, T., Chumakov, A., Dubrovinsky, L.Oxidation state of majoritic garnet inclusions in diamond.Goldschmidt Conference, abstract 1p.Africa, South Africadeposit, Jagersfontein

Abstract: Diamond inclusions are the only samples from the mantle transition zone (410-660 km) and the lower mantle. Majoritic garnet is a rare inclusion, limited to pressures of ~8-20 Gpa with Si content being indicative of depth of re-equilibration. These garnet inclusions can therefore provide information on properties of the transition zone such as oxidation state. In this study, we used Synchrotron Mössbauer Source (SMS) to determine the ferric-ferrous ratios of 13 small (30 to 100 micrometers diameter) majoritic inclusions in diamonds from Jagersfontein. The studied inclusions have pyroxenitic affinities [1], with compositions intermediate between typical peridotite and eclogite. They contain 4.62-11.2 wt% CaO, 0.03-0.34 wt% Cr2O3 and Mg# of 0.65-0.81. Minimum pressures for their equilibration using Beyer and Frost [2] barometer are between 8 and 18 GPa with at least 4 of these inclusions being formed in the transition zone. The Fe3+/Fetotal ratios in the garnets increase from 0.08±0.01 to 0.30±0.03 with increasing pressure. These values define a clear extension of the trend apparent in the data from peridotite xenoliths crystallised at lower pressures. Thermodynamic calculations suggest that these high ferric contents correspond to oxygen fugacities above the FeFeO (IW) buffer, which means that the high Fe3+ contents were not generated by disproportionation of Fe2+ to Fe3+ and Fe0 . It is more likely that carbonate was the oxidising agent responsible for generating the high Fe3+ of these garnets.
DS201902-0285
2018
Vasiukov, D.M.Kiseeva, E.S., Vasiukov, D.M., Wood, B.J., McCammon, C., Stachel, T., Bykov, M., Bykova, E., Chumakov, A., Cerantola, V., Harris, J.W., Dubrovinsky, L.Oxidized iron in garnets from the mantle transition zone.Nature Geoscience, Vol. 11, pp. 144-147. Africa, South Africadeposit - Jagersfontein

Abstract: The oxidation state of iron in Earth’s mantle is well known to depths of approximately 200?km, but has not been characterized in samples from the lowermost upper mantle (200-410?km depth) or the transition zone (410-660?km depth). Natural samples from the deep (>200?km) mantle are extremely rare, and are usually only found as inclusions in diamonds. Here we use synchrotron Mössbauer source spectroscopy complemented by single-crystal X-ray diffraction to measure the oxidation state of Fe in inclusions of ultra-high pressure majoritic garnet in diamond. The garnets show a pronounced increase in oxidation state with depth, with Fe3+/(Fe3++ Fe2+) increasing from 0.08 at approximately 240?km depth to 0.30 at approximately 500?km depth. The latter majorites, which come from pyroxenitic bulk compositions, are twice as rich in Fe3+ as the most oxidized garnets from the shallow mantle. Corresponding oxygen fugacities are above the upper stability limit of Fe metal. This implies that the increase in oxidation state is unconnected to disproportionation of Fe2+ to Fe3+ plus Fe0. Instead, the Fe3+ increase with depth is consistent with the hypothesis that carbonated fluids or melts are the oxidizing agents responsible for the high Fe3+ contents of the inclusions.
DS2000-0375
2000
Vasquez, A.M.Hacker, B.R., Andersen, T.B., Vasquez, A.M., Root, D.B.Exhumation of Norwegian ultra high pressure (UHP) eclogites: II. Plutonism and extension beneath the Solund Basin.Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-32.NorwayEclogites, Subduction - slab
DS1990-0218
1990
Vasseur, G.Bodinier, J.L., Vasseur, G., Vernieres, J., Dupuy, C., Fabries, J.Mechanisms of mantle metasomatism: geochemical evidence from the Lherzorogenic peridotiteJournal of Petrology, Vol. 31, No. 3, June pp. 597-628GermanyMantle Metasomatism, Geochemistry
DS1991-1019
1991
Vasseur, G.Lucazeau, F., Lesquer, A., Vasseur, G.Trends of heat flow density from West AfricaTerrestrial Heat Flow and the Lithosphere Structure, editors Cermak, V. and, Springer Verlag, pp. 417-425West AfricaHeat flow, Geophysics
DS1993-1408
1993
Vasseur, G.Sebagenzi, M.N., Vasseur, G., Louis, P.First heat flow density determinations from south eastern Zaire, CentralAfricaJournal of African Earth Studies, Vol. 16, No. 4, pp. 413-424Democratic Republic of CongoHeat flow
DS1993-1409
1993
Vasseur, G.Sebagenzi, M.N., Vasseur, G., Louis, P.First heat flow density determinations from southeastern Zaire (CentralAfrica).Journal of African Earth Sciences, Vol. 16, No. 4, May, pp. 413-424.Democratic Republic of CongoMantle, Pan-African belt, Heat flow
DS2002-1653
2002
Vassilieva, V.A.Vassilieva, V.A.Garnet group typochemism in melilite bearing rocks of the Turiy massif, Kola Peninsula, Russia.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.251.Russia, Kola PeninsulaMelilite
DS2002-1654
2002
Vassilieva, V.A.Vassilieva, V.A., Rozhdestvenskaya, I.V., Evdokimov, M.D.The accessory minerals in melilite bearing rocks from the Turiy massif, ( Kola Peninsula) Russia.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.251.Russia, Kola PeninsulaMelilite
DS1996-1473
1996
Vassjoki, M.Vassjoki, M.Explanation of the geochronological map of southern Finland: the development of the continental crust.Geological Survey of Finland, Report Inv. 135, 27p. map 1: 100, 000FinlandGeochronology, map, Svecofennian Orogeny
DS2000-0151
2000
Vasudev, V.N.Chadwick, B., Vasudev, V.N., Hegde, G.V.The Dharwar Craton, southern India, interpreted as the result of Late Archean oblique convergence.Precambrian Research, Vol. 99, No. 1-2, pp. 91-111.India, south IndiaTectonics, Craton - Dharwar
DS200612-0238
2005
Vasudev, V.N.Chalapathi Rao, N.V., Hanuma Prasad, M., Vasudev, V.N.Archean primary source for the diamonds in the Wairagarh area, Garchiroli district, Maharashira.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 107-112.India, Bastar CratonDiamond genesis
DS1990-1045
1990
Vasudevan, K.Milkereit, B., White, D., Percival, J.A., Vasudevan, K., ThurstonHigh resolution seismic reflection profiles across the Kapuskasing structure #1G.s.c. Forum January 16-17, Ottawa, Poster display AbstractOntarioGeophysics, Seismics
DS1991-1155
1991
Vasudevan, K.Milkereit, B., White, D.J., Percival, J.A., Vasudevan, K., ThurstonHigh resolution seismic reflection profiles across the Kapuskasing structure #2Ontario Geological Survey Open File, Open File No. 5781, 37pOntarioGeophysics -seismics, Kapuskasing structural zone
DS1996-1474
1996
Vasudevan, K.Vasudevan, K., Cook, F.A.Skeletonization and fractal behaviour of deep crustal seismic dat a from the central Alberta Transect.Ross, G.M. Lithoprobe Alberta, No. 51, pp. 11-18.AlbertaGeophysics - seismics
DS1998-1524
1998
Vasudevan, K.Vasudevan, K., Cook, F.A.Skeletons and fractals: a statistical approach to deep crustal seismic dat a processing and interrpetation.Tectonophysics, Vol. 286, No. 1-4, pp. 93-109.AlbertaGeophysics - seismics
DS2001-1197
2001
Vasudevan, K.Vasudevan, K., Cook, F.A.Time frequency analysis of deep crustal reflection seismic dat a using Wigner-Ville distributions.Canadian Journal of Earth Sciences, Vol. 38, No. 7, July pp. 1027-35.Alberta, southernGeophysics - seismics
DS2003-0271
2003
Vasudevan, K.Cook, F.A., Vasudevan, K.Are there relict crustal fragments beneath the Moho?Tectonics, Vol. 22, 3, 1026 DOI 10.1029/2001TC001341Northwest Territories, MantleGeophysics - seismics, structure, tectonics, lithology
DS200412-0359
2003
Vasudevan, K.Cook, F.A., Vasudevan, K.Are there relict crustal fragments beneath the Moho?Tectonics, Vol. 22, 3, 1026 DOI 10.1029/2001 TC001341Canada, Northwest TerritoriesGeophysics - seismics, structure, tectonics, lithology
DS200412-0498
2004
Vasudevan, K.Eaton, D., Vasudevan, K.Skeletonization of aeromagnetic data.Geophysics, Vol. 69, 2, pp. 478-488.Canada, Northwest Territories, QuebecLineaments, pattern recognition methodology, Great Slav
DS201012-0264
2010
Vasudevan, K.Hammer, P.T.C., Clowes, R.M., Cook, F.A., Van der Velden, A.J., Vasudevan, K.The lithoprobe trans continental lithospheric cross sections: imaging the internal structure of the North American continent.Canadian Journal of Earth Sciences, Vol. 47, 5, pp. 821-957.Canada, United StatesGeophysics - seismics
DS201312-0939
2013
Vasyukova, E.Vasyukova, E.Petrology of the lamprophyres.Goldschmidt 2013, 1p. AbstractMantleLamprophyre
DS201412-0945
2014
Vasyukova, E.Vasyukova, E.Isotopic dat a for the Chuya lamprophyre dikes of the Gorniy and Mongolian Altai ( Russia and Mongolia) as a key to their petrogenesis.ima2014.co.za, PosterRussia, Asia, MongoliaLamprophyre
DS202102-0177
2019
Vasyukova, E.A.Chayka, I., Izokh, A.E., Vasyukova, E.A.Can low-titanium lamproite magmas produce ore deposits? Evidence from Mesozoic Aldan Shield lamproites. *** note dateResearchgate Conference paper, 335395794 5p. PdfRussialamproites

Abstract: Lamproites and lamprophyres from Ryabinovoye gold deposit (Aldan Shield, Siberia) were studied. We demonstrate that these rocks, varying from Ol-Di-Phl-lamproites to syenite-porphyries, form a continuous series of lamproite magma differentiation. At the stage of phlogopite and clinopyroxene crystallization, silicate-carbonate and then carbonate-salt immiscibilities occur. A suggestion is that during these processes LREE, Y, U, Sr and Ba distribute to a phosphate-fluoride fraction and probably accumulate in apatite-fluorite gangues. Based on our results and considering existing data onore-bearing massifs within Central Aldan (lnagli, Ryabinoviy) and also of the Nam-Xe ore-bearing province (Vietnam), we concluded that Au, PGE and Th-U-Ba-REE deposits can be genetically connected with low-titanium lamproite magmas.
DS201412-0946
2014
Vasyukova, O.Vasyukova, O., Williams-Jones, A.E.Fluoride-silicate melt immiscibility and its role in REE ore formation: evidence from the Strange Lake rare metal deposit, Quebec-Labrador, Canada.Geochimica et Cosmochimica Acta, Vol. 139, pp. 110-130.Canada, QuebecDeposit - Strange Lake
DS201512-1990
2015
Vasyukova, O.Williams-Jones, A.E., Vasyukova, O.Fluoride-silicate melt immisicibility and the formation of the pegmatite-hosted Strange Lake REE deposit, Quebec-Labrador.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 91-96.Canada, Quebec, LabradorRare earths
DS201909-2101
2019
Vasyukova, O.Vasyukova, O., William-Jones, A.E.Tracing the REE composition of an evolving peralkaline granitic magma via the composition of Arfvedsonite.Goldschmidt2019, 1p. AbstractGlobalREE

Abstract: There are a number of peralkaline granitic plutons, which show significant enrichment in the REE and, in some cases, host REE deposits; the grades of the deposits represent the final enrichment in the REE. Thus, it is important to understand how this enrichment occurs and by which processes, in order to develop tools for discovering other similar deposits. The best way to reconstruct the REE composition of an evolving magma is by analysing melt inclusions, i.e., the tiny samples of magma trapped at different stages of its evolution. Such inclusions, however, are rarely preserved and difficult to analyse. Another way to reconstruct the REE composition of an evolving magma is to analyse the REE composition of the minerals crystallising from this magma at different stages in its evolution. This, however, requires that the REE mineral-melt partition coefficients be known. Here we present a model for the calculation of arfvedsonite-melt REE partition coefficients, based on data from the Strange Lake pluton (Canada). The model employs the lattice strain theory, which derives mineral-melt partition coefficients from the values of the ideal partition coefficient (D0), the ideal radius (r0) and the elastic response (EM) of the mineral. There are two sites in arfvedsonite into which the REE partition, namely the M4 site, which is preferred by the light REE and the M2 site, which is preferred by the heavy REE. Partition coefficients for both sites were modelled. Significantly, values of D0, r0 and EM for the M4 site vary linearly with the Ca content of the arfvedsonite, whereas for the M2 site these parameters vary linearly with the temperature of arfvedsonite crystallisation. Using these two relationships, a set of equations was derived, which enables the calculation of arfvedsonite-melt REE partition coefficients for any arfvedsonite for which the Ca content and crystallisation temperature are known. This model was tested on a peralkaline granitic pegmatite from the Amis complex (Namibia), for which data on the composition of the amphibole and corresponding magma (melt inclusions) have been reported. The model successfully predicts the concentrations of the various REE in the Amis magma, thereby providing confidence that it can be used to trace the REE content of evolving granitic magmas in other plutons.
DS201805-0988
2018
Vasyukova, O.V.Vasyukova, O.V., Williams-Jones, A.E.Direct measurement of metal concentrations in fluid inclusions, a tale of hydrothermal alteration and REE ore formation from Strange Lake, Canada.Chemical Geology, Vol. 483, pp. 385-396.Canada, Quebec, LabradorRare earths

Abstract: Granites and pegmatites in the Strange Lake pluton underwent extreme enrichment in high field strength elements (HFSE), including the rare earth elements (REE). Much of this enrichment took place in the most altered rocks, and is expressed as secondary minerals, showing that hydrothermal fluids played an important role in HFSE concentration. Vasyukova et al. (2016) reconstructed a P-T-X path for the evolution of these fluids and provided evidence that hydrothermal activity was initiated by exsolution of fluid during crystallisation of border zone pegmatites (at ~450-500?°C and 1.1?kbar). This early fluid comprised a high salinity (25?wt% NaCl) aqueous phase and a CH4?+?H2 gas. During cooling, the gas was gradually oxidised, first to higher hydrocarbons (e.g., C2H6, C3H8), and then to CO2, and the salinity decreased to 4?wt% (~250-300?°C), before increasing to 19?wt%, due to fluid-rock interaction (~150?°C). Here, we present crush-leach fluid inclusion data on the concentrations of the REE and major ligands at different stages of the evolution of the fluid. The chondrite-normalised REE profile of the fluid evolved from light REE (La-Nd)-enriched at high temperature (~400?°C, Stages 1-2a) to middle REE (Sm-Er)-enriched at 360 to 250?°C (Stages 2b-3) and strongly heavy REE (Tm-Lu)-enriched at low temperature (150?°C, Stage 5). These changes in the REE distribution were accompanied by changes in the concentrations of major ligands, i.e., Cl? was the dominant ligand in Stages 1, 2, 4 and 5, whereas HCO3? was dominant in Stage 3. Alteration of arfvedsonite to aegirine and/or hematite contributed strongly to the mobilisation of the REE. This alteration released middle REE (MREE) and heavy REE (HREE), which either partitioned into the fluid or precipitated directly as bastnäsite-(Ce), ferri-allanite-(Ce) or gadolinite-(Y). Replacement of primary fluorbritholite-(Ce), which crystallised from an immiscible fluoride melt and altered to bastnäsite-(Ce), was also important in mobilising the REE (MREE). This paper presents the first report of the distribution of the REE in an evolving hydrothermal fluid. Using this distribution, in conjunction with information on the changing physicochemical conditions, the study identifies the sources of REE enrichment, reconstructs the path of REE concentration, and evaluates the REE mineralising capacity of the fluid. Finally, this information is integrated into a predictive model for REE mobilisation applicable not only to Strange Lake but any REE ore-forming system, in which hydrothermal processes were important.
DS201902-0330
2019
Vasyukova, O.V.Vasyukova, O.V., Williams-Jones, A.E.Closed system fluid-mineral-mediated trace element behaviour in peralkaline rare metal pegmatites: evidence from Strange Lake.Chemical Geology, Vol. 505, pp. 86-99.Canada, Quebec, Labradorgeochemistry

Abstract: Large peralkaline complexes are ‘factories’ that have produced a variety of ‘exotic’ minerals including high field strength element minerals. In most cases, these minerals are secondary and crystallise in a hydrothermal paragenesis that is extremely difficult to decipher due to the complexity of the textural relationships. The Strange Lake pluton is one of these complexes, and contains 37 exotic minerals, most of which are secondary. Adding to the difficulty in establishing a comprehensive paragenesis for these minerals and an alteration/precipitation path for the pluton is the fact that there were several stages of crystallisation of the same exotic and common secondary minerals, e.g., bastnäsite, fluocerite, gadolinite, aegirine, fluorite, and zircon. In this paper, we present a model, which describes a detailed path for the alteration and precipitation of minerals in the closed hydrothermal system of a peralkaline granitic pegmatite, based on direct measurements of the evolving composition of the aqueous fluid that exsolved from the late-stage magma crystallising rare-metal pegmatites in the Strange Lake pluton. The driving force for this evolution was cooling-induced oxidation that ultimately transformed the CH4-H2 gas in this fluid to CO2. This led to a large drop in the pH, which was a major control on the composition of the fluid and the crystallisation of secondary minerals. Although large numbers of minerals formed and were replaced during the different stages of fluid evolution, the changing chemistry of the fluid was largely a response to the alteration of four minerals, namely arfvedsonite, elpidite, narsarsukite and fluorite. The earliest stage of alteration, which took place at ~360?°C, was marked by the replacement of arfvedsonite by aegirine. This alteration decreased salinity and released K, Li, and Rb to the fluid, causing K-metasomatism. At ~300?°C, CH4 and higher hydrocarbons reacted to produce CO2. This caused a massive drop in pH from a value?>?10 to a value of ~3 and intense alteration, which included the dissolution of fluorite, the breakdown of elpidite to zircon and quartz and the replacement of narsarsukite by titanite. With ongoing dissolution of fluorite, Ca activity reached a level sufficient to promote the alteration of elpidite to armstrongite or gittinsite. This was accompanied by alteration of arfvedsonite to ferroceladonite and microcline to Al-phyllosilicates, enriching the fluid in Na, Fe and F. Soon after, there was a near total loss of CO2 (at ~230?°C). This loss was catastrophic and was focused along conical fractures (these developed as a result of the collapse of the roof of the pluton), with resultant fragmentation of the rocks along the fluid path. Alteration to phyllosilicates continued after the loss of CO2, as the system cooled to ~190?°C. This marked the beginning of the final stage of alteration, which involved the replacement of arfvedsonite by aegirine and hematite. It also coincided with large scale hematisation within the pluton. Finally, it led to the cementation of the fragments along the fluid path to form the fluorite-hematite ring breccia that is now evident at the margins of the pluton. The model of fluid evolution presented here is potentially applicable to many other peralkaline complexes. The only requirements are that the system was closed until a relatively late stage and that the exsolved fluid was saline and contained a reduced carbonic component. This is a feature of many peralkaline complexes, most notably, the Khibiny and Lovozero complexes in Russia, and Ilímaussaq in Greenland.
DS201905-1084
2019
Vasyukova, O.V.Vasyukova, O.V., Williams-Jones, A.E.Direct measurement of metal concentrations in fluid inclusions, a tale of hydrothermal alteration and REE ore formation from Strange Lake, Canada.Chemical Geology, Vol. 483, pp. 385-396.Canada, OntarioREE

Abstract: Granites and pegmatites in the Strange Lake pluton underwent extreme enrichment in high field strength elements (HFSE), including the rare earth elements (REE). Much of this enrichment took place in the most altered rocks, and is expressed as secondary minerals, showing that hydrothermal fluids played an important role in HFSE concentration. Vasyukova et al. (2016) reconstructed a P-T-X path for the evolution of these fluids and provided evidence that hydrothermal activity was initiated by exsolution of fluid during crystallisation of border zone pegmatites (at ~450-500?°C and 1.1?kbar). This early fluid comprised a high salinity (25?wt% NaCl) aqueous phase and a CH4?+?H2 gas. During cooling, the gas was gradually oxidised, first to higher hydrocarbons (e.g., C2H6, C3H8), and then to CO2, and the salinity decreased to 4?wt% (~250-300?°C), before increasing to 19?wt%, due to fluid-rock interaction (~150?°C). Here, we present crush-leach fluid inclusion data on the concentrations of the REE and major ligands at different stages of the evolution of the fluid. The chondrite-normalised REE profile of the fluid evolved from light REE (La-Nd)-enriched at high temperature (~400?°C, Stages 1-2a) to middle REE (Sm-Er)-enriched at 360 to 250?°C (Stages 2b-3) and strongly heavy REE (Tm-Lu)-enriched at low temperature (150?°C, Stage 5). These changes in the REE distribution were accompanied by changes in the concentrations of major ligands, i.e., Cl? was the dominant ligand in Stages 1, 2, 4 and 5, whereas HCO3? was dominant in Stage 3. Alteration of arfvedsonite to aegirine and/or hematite contributed strongly to the mobilisation of the REE. This alteration released middle REE (MREE) and heavy REE (HREE), which either partitioned into the fluid or precipitated directly as bastnäsite-(Ce), ferri-allanite-(Ce) or gadolinite-(Y). Replacement of primary fluorbritholite-(Ce), which crystallised from an immiscible fluoride melt and altered to bastnäsite-(Ce), was also important in mobilising the REE (MREE). This paper presents the first report of the distribution of the REE in an evolving hydrothermal fluid. Using this distribution, in conjunction with information on the changing physicochemical conditions, the study identifies the sources of REE enrichment, reconstructs the path of REE concentration, and evaluates the REE mineralising capacity of the fluid. Finally, this information is integrated into a predictive model for REE mobilisation applicable not only to Strange Lake but any REE ore-forming system, in which hydrothermal processes were important.
DS1960-1226
1969
Vatlin, B.P.Vatlin, B.P., Izarov, V.T., et al.Estimating the Effectiveness of Linear Methods of Seperating Magnetic and Gravity Fields in Order to Locate Kimberlite Pipes Beneath Trap Rocks.Razved. Prom. Geofiz., No. 92, PP. 42-49.Russia, YakutiaKimberlite, Geophysics
DS200512-0212
2005
Vatteville, J.Davaille, A., Vatteville, J.On the transient nature of mantle plumes.Geophysical Research Letters, Vol. 32, 14, July 28, L14309MantleTectonics
DS201801-0064
2017
Vatuva, A.Simon, S.J., Wei, C.T., Viladkar, S.G., Ellmies, R., Soh, Tamech, L.S., Yang, H., Vatuva, A.Metamitic U rich pyrochlore from Epembe sovitic carbonatite dyke, NW Namibia.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 12.Africa, Namibiadeposit - Epembe

Abstract: The Epembe carbonatite dyke is located about 80 km north of Opuwo, NW Namibia. The 10 km long dyke is dominated by massive and banded sövitic carbonatite intrusions. Two distinct type of sövite have been recognized: (1) coarse-grained light grey Sövite I which is predominant in brecciated areas and (2) medium- to fine-grained Sövite II which hosts notable concentrations of pyrochlore and apatite. The contact between the carbonatite and basement gneisses is marked by K-feldspar fenite. The pyrochlore chemistry at Epembe shows a compositional trend from primary magmatic Ca-rich pyrochlore toward late hydrothermal fluid enriched carbonatite phase, giving rise to a remarkable shift in chemical composition and invasion of elements such as Si, U, Sr, Ba, Th and Fe. Enrichment in elements like U, Sr and Th lead to metamictization, alteration and A-site vacancy. It is therefore suggested that the carbonatite successive intrusive phases assimilated primary pyrochlore leading to extreme compositional variation especially around the rims of the pyrochlore. The genesis of the Epembe niobium deposit is linked to the carbonatite magmatism but the mechanism that manifested such niobium rich rock remains unclear and might be formed as a result of cumulate process and/or liquid immiscibility of a carbonate-silicate pair.
DS2001-0091
2001
VauchezBascou, J., Barruol, Vauchez, Mainprice, EgydiosilvaEBSD measured lattice preferred orientations and seismic properties of eclogitesTectonophysics, Vol. 342, No. 2, pp. 61-80.GlobalGeophysics - seismics, Eclogites
DS1987-0762
1987
Vauchez, A.Vauchez, A., Kessler, S.F., Lecorche, J.P., Villeneuve, M.Southward extrusion tectonics during the Carboniferous Africa-North American collisionTectonophysics, Vol. 142, No. 2-4, November 1, pp. 317-322South AfricaTectonics
DS1991-0311
1991
Vauchez, A.Corsini, M., Vauchez, A., Archanjo, C., De Sa, E.F.J.Strain transfer at continental scale from a transcurrent shear zone to a transpressional fold belt: the Patos-Serido system, northeastern BrasilGeology, Vol. 19, No. 6, June pp. 586-589BrazilStructure -shear zone, Brasiliano-pan-African Orogeny
DS1991-1783
1991
Vauchez, A.Vauchez, A., Nicolas, A.Mountain building: strike parallel motion and mantle anisotropyTectonophysics, Vol. 185, pp. 183-201.MantleTectonics, Orogenic belts
DS1992-1599
1992
Vauchez, A.Vauchez, A., Egydio da Silva, M.Termination of a continental scale strike slip fault in partially meltedcrust: the West Pernambuco shear zone, northeast BrasilGeology, Vol. 20, No. 11, November pp. 1007-1010BrazilTectonics, Shear zone
DS1993-1129
1993
Vauchez, A.Nicolas, A., Freydier, Cl., Godard, M., Vauchez, A.Magma chambers at oceanic ridges: how large?Geology, Vol. 21, No. 1, January pp. 53-56GlobalMagma, Geophysics -seismics
DS1994-1789
1994
Vauchez, A.Tommasi, A., Vauchez, A., Fernandes, L.A.D., Porcher, C.C.Magma assisted strain localization in an orogen parallel transcurrent shearzone of southern BrasilTectonics, Vol. 13, No. 2, April, pp. 421-437BrazilStructure, Pan African Dom Feliciano belt
DS1994-1844
1994
Vauchez, A.Vauchez, A., Tommasi, A., Ehydio-Silva, M.Self indentation of a heterogeneous continental lithosphereGeology, Vol. 22, No. 11, November pp. 967-970.BrazilCraton, Sao Francisco
DS1995-1340
1995
Vauchez, A.Neves, S.P., Vauchez, A.Successive mixing and mingling of magmas in a plutonic complex of northeastBrasilLithos, Vol. 34, pp. 275-299BrazilMagmatism, Fazenda Nova Serra da Japegana complex
DS1996-0302
1996
Vauchez, A.Corsini, M., Vauchez, A., Caby, R.Ductile duplexing at a band of a continental scale strike slip shear zone:example from northeast BrasilJournal of Structural Geology, Vol. 18, No. 4, Apr.1, pp. 385-394BrazilStructure, Lineament
DS1997-0080
1997
Vauchez, A.Barruol, G., Silver, P.G., Vauchez, A.Seismic anisotropy in the eastern United States: deep structure of acomplex continental plate.Journal of Geophysical Research, Vol. 102, No. 4, April 10, pp. 8329-48.Appalachia, MidcontinentGeophysics - seismics, Tectonics
DS1998-0278
1998
Vauchez, A.Corsini, M., De Figueiredo, L.L., Vauchez, A.Thermal history of the Pan-African Brasiliano Borborema Province of northeast Brasil from 40Kr 39 Kr analysisTectonophysics, Vol. 285, No. 1-2, Feb. 15, pp. 103-118BrazilGeothermometry, Borborema
DS1998-1525
1998
Vauchez, A.Vauchez, A., Tommasi, A., Barruol, G.Rheological heterogeneity, mechanical anisotropy and deformation of the continental lithosphere.Tectonophysics, Vol. 296, No. 1-2, . Oct. 30, pp. 61-86.MantleTectonics, Lithosphere
DS1999-0739
1999
Vauchez, A.Tommasi, A., Tikoff, B., Vauchez, A.Upper mantle tectonics: three dimensional deformation, olivine, crystallographic fabrics and seismic propertyEarth and Planetary Science Letters, Vol. 169, 1-2, Apr.30, pp.173-86.MantleGeophysics - seismics, Tectonics
DS2001-1163
2001
Vauchez, A.Tommasi, A., Vauchez, A.Continental rifting parallel to ancient collisional belts: an effect of the mechanical anisotropy of mantleEarth and Planetary Science Letters, Vol. 185, No. 1-2, Feb.15, pp.199-210.MantleLithosphere - rifts, Tectonics
DS2001-1198
2001
Vauchez, A.Vauchez, A., Garrido, C.J.Seismic properties of an asthenospherized lithospheric mantle: constraints from lattic preferred orientationsEarth and Planetary Science Letters, Vol. 192, No. 2, pp. 235-49.SpainPeridotites, Rhonda Massif
DS2003-0573
2003
Vauchez, A.Heintz, M., Vauchez, A., Assumpcao, M., Barruol, G., EgydioSilva, M.Shear wave splitting in SE Brazil: an effect of active or fossil upper mantle flow, orEarth and Planetary Science Letters, Vol. 211, 1-2, June 15, pp. 79-95.Brazil, south EastGeophysics - seismic anisotropy, crust mantle coupling
DS2003-0574
2003
Vauchez, A.Heinz, M., Vauchez, A., Asuumpcao, M., Barruol, G., Egydio Silva, M.Shear wave splitting in SE Brazil: an effect of active or fossil upper mantle flow or both?Earth and Planetary Science Letters, Vol. 211, 1-2, pp. 79-95.BrazilBlank
DS200412-0816
2003
Vauchez, A.Heintz, M., Vauchez, A., Assumpcao, M., Barruol, G., EgydioSilva, M.Shear wave splitting in SE Brazil: an effect of active or fossil upper mantle flow, or both?Earth and Planetary Science Letters, Vol. 211, 1-2, June 15, pp. 79-95.South America, BrazilGeophysics - seismic anisotropy, crust mantle coupling
DS200512-0417
2005
Vauchez, A.Heintz, M., De Bayle, E., Vauchez, A.Upper mantle structure of the South American continent and neighbouring oceans from surface wave tomography.Tectonophysics, Vol. 406, 1-2, pp. 115-139.South AmericaTomography
DS200512-1130
2005
Vauchez, A.Vauchez, A., Dineur, F., Rudnick, R.Microstructure, texture and seismic anisotropy of the lithospheric mantle above a mantle plume: insights from the Labait volcano xenoliths (Tanzania).Earth and Planetary Science Letters, Vol. 232, 3-4, April 15, pp. 295-314.Africa, TanzaniaCratonic lithosphere
DS200612-0049
2006
Vauchez, A.Assumpcao, M., Heintz, M., Vauchez, A., Egydio Silva, M.Upper mantle anisotropy in SE and Central Brazil from SKS splitting: evidence of asthenospheric flow around a cratonic keel.Earth and Planetary Science Letters, Vol. 250, 1-2, pp. 224-240.South America, BrazilGeophysics - seismic, fast polarization
DS200612-0050
2006
Vauchez, A.Assumpcao, M., Heintz, M., Vauchez, A., Silva, M.E.Upper mantle anisotropy in SE and Central Brazil from SKS splitting: evidence of asthenospheric flow around a cratonic keel.Earth and Planetary Science Letters, Vol.250, 1-2, pp. 224-240.South America, BrazilGeophysics - seismics
DS200712-0604
2007
Vauchez, A.Le Roux, V., Bodinier, J-L., Tommasi, A., Alard, O., Dautria, J-M., Vauchez, A., Riches, A.J.V.The lherz spinel lherzolite: refertilized rather than pristine mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 599-612.MantleLherzolite chemistry
DS200712-0605
2007
Vauchez, A.Le Roux, V., Bodinier, J-L., Tommasi, A., Alard, O., Dautria, J-M., Vauchez, A., Riches, A.J.V.The lherz spinel lherzolite: refertilized rather than pristine mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 599-612.MantleLherzolite chemistry
DS200812-0640
2008
Vauchez, A.Le Roux, V., Tommasi, A., Vauchez, A.Feedback between melt percolation and deformation in an exhumed lithosphere asthenosphere boundary.Earth and Planetary Science Letters, Vol. 274, pp. 410-413.MantleMelting
DS200812-0794
2008
Vauchez, A.Neves, S.P., Tommasi, A., Vauchez,A., Hassani, R.Intraplate continental deformation: influence of a heat producing layer in the lithospheric mantle.Earth and Planetary Science Letters, Vol. 274, pp. 392-400.MantleMetasomatism
DS200812-1180
2008
Vauchez, A.Tommasi, A., Vauchez, A., Ionov, D.A.Deformation, static recrystallization, and reactive melt transport in shallow subcontinental mantle xenoliths ( Tok Cenozoic volcanic field, SE Siberia).Earth and Planetary Science Letters, Vol. 272, 1-2, pp. 65-77.Russia, SiberiaXenoliths
DS201212-0485
2012
Vauchez, A.Monie, P., Bosch, D., Bruguier, O., Vauchez, A., Rolland, Y., Nsungani, P., Buta Neto, A.The Late Neoporterozoic/Early Paleozoic evolution of the West Congo Belt of NW Angola: geochronological (U Pb Ar Ar) and petrostructual constraints.Terra Nova, Vol. 24, 3, pp. 238-247.Africa, AngolaGeochronology
DS201212-0486
2012
Vauchez, A.Monie, P., Bosch, D., Bruguier, O., Vauchez, A., Rolland, Y., Nsungani, P., Buta Nto, A.The Late Neoproterozoic/Early Palezoic evolution of the West Congo belt of NW Angola: geochronological (U-Pb and Ar-Ar) and petrostructural constraints.Terra Nova, in press availableAfrica, AngolaGeochronology
DS201312-0919
2013
Vauchez, A.Tommasi, A., Baptiste, V., Soustelle, V., Le Roux, V., Mainprice, D., Vauchez, A.Heterogeneity and anisotropy in the lithospheric mantle.Goldschmidt 2013, AbstractMantleGeophysics
DS201412-0253
2014
Vauchez, A.Frets, E.C., Tommasi, A., Garrido, C.J., Vauchez, A., Mainprice, D., Targuisti, K., Amri, I.The Beni Boussera peridotite ( Rif belt, Morocco): an oblique slip low angle shear zone thinning the subcontinental mantle lithosphere.Journal of Petrology, Vol. 55, 2, pp. 283-313.Africa, MoroccoPeridotite
DS201412-0478
2014
Vauchez, A.Kourim, F., Bodinier, J-L., Alard, O., Bendaoud, A., Vauchez, A., Dautria, J-M.Nature and evolution of the lithospheric mantle beneath the Hoggar Swell ( Algeria): a record from mantle xenoliths.Journal of Petrology, Vol. 55, pp. 2249-2280.Africa, AlgeriaXenoliths
DS201902-0263
2018
Vauchez, A.Cavalcante, C., Hollanda, M.H., Vauchez, A., Kawata, M.How long can the middle crust remain partially molten during orogeny?Geology, Vol. 46, pp. 839-852.South America, Brazil, Africa, Congomelting

Abstract: Extensive partial melting of the middle to lower crustal parts of orogens, such as of the current Himalaya-Tibet orogen, significantly alters their rheology and imposes first-order control on their tectonic and topographic evolution. We interpret the late Proterozoic Araçuaí orogen, formed by the collision between the São Francisco (Brazil) and Congo (Africa) cratons, as a deep section through such a hot orogen based on U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon ages and Ti-in-zircon and Zr-in-rutile temperatures from the Carlos Chagas anatectic domain. This domain is composed of peraluminous anatexites and leucogranites that typically exhibit interconnected networks of garnet-rich leucosomes or a magmatic foliation. Zirconium-in-rutile temperatures range from 745 to 820 °C, and the average Ti-in-zircon temperature ranges from 712 to 737 °C. The geochronologic and thermometry data suggest that from 597 to 572 Ma this domain was partially molten and remained so for at least 25 m.y., slowly crystallizing between temperatures of ?815 and >700 °C. Significant crustal thickening must have occurred prior to 600 Ma, with initial continental collision likely before 620 Ma, a time period long enough to heat the crust to temperatures required for widespread partial melting at middle crustal levels and to favor a "channel flow" tectonic behavior.
DS201908-1787
2019
Vauchez, A.Liu, S., Tommasi, A., Vauchez, A., Mazzucchelli, M.Crust mantle coupling during continental convergence and break-up: constraints from peridotite xenoliths from the Bororema province, northeast Brazil.Tectonophysics, Vol. 766, pp. 249-269.South America, Brazilgeophysics - seismic

Abstract: We studied a suite of mantle xenoliths carried by Cenozoic volcanism in the Borborema Province, NE Brazil. These xenoliths sample a subcontinental lithospheric mantle affected by multiple continental convergence and rifting events since the Archean. Equilibrium temperatures indicate a rather hot geotherm, implying a ca. 80?km thick lithosphere. Most xenoliths have coarse-granular and coarse-porphyroclastic microstructures, recording variable degrees of annealing following deformation. The high annealing degree and equilibrated pyroxene shapes in coarse-granular peridotites equilibrated at ~900?°C indicate that the last deformation event that affected these peridotites is several hundreds of Ma old. Coarse-porphyroclastic peridotites equilibrated at 950-1100?°C probably record younger (Cretaceous?) deformation in the deep lithospheric mantle. In addition, a few xenoliths show fine-porphyroclastic microstructures and equilibrium temperatures ?1200?°C, which imply recent deformation, probably related to the dykes that fed the Cenozoic volcanism. Chemical and microstructural evidence for reactive percolation of melts is widespread. Variation in textural and chemical equilibrium among samples implies multiple melt percolation events well spaced in time (from Neoproterozoic or older to Cenozoic). Crystal preferred orientations of olivine and pyroxenes point to deformation controlled by dislocation creep with dominant activation of the [100](010) and [001]{0kl} slip systems in olivine and pyroxenes, respectively, for all microstructures. Comparison of xenoliths' seismic properties to SKS splitting data in the nearby RCBR station together with the equilibrated microstructures in the low-temperature xenoliths point to coupled crust-mantle deformation in the Neoproterozoic (Brasiliano) continental-scale shear zones, which is still preserved in the shallow lithospheric mantle. This implies limited reworking of the lithospheric mantle in response to extension during the opening of the Equatorial Atlantic in the Cretaceous, which in the present sampling is restricted to the base of the lithosphere.
DS202111-1781
2021
Vauchez, A.Rezende Fernandes, P., Tommasi, A., Vauchez, A., Pachero Neves, S., Nannini, F.The Sao Francisco cratonic root beneath the Neoproterozoic Brasilia belt ( Brazil): petrophysical data from kimberlite xenoliths.Tectonophysics, Vol. 816, 220011, 23p. PdfSouth America, Brazildeposit - Limeira-1, Indaia-1, Canastra-1

Abstract: Petrostructural analysis of 31 mantle xenoliths from three kimberlitic pipes intruding the Neoproterozoic Brasilia belt close to the southwestern margin of the São Francisco craton (SFC) reveals microstructures and compositions similar to those observed in cratonic roots worldwide. (1) The spinel-peridotites sampling the upper section of the lithospheric mantle have dominantly refractory modal and mineral compositions, whereas garnet-peridotites sampling the deep lithospheric mantle have more fertile compositions, consistent with those observed in cratonic roots worldwide. (2) The spinel-peridotites present a variation in microstructure from coarse-granular to coarse-porphyroclastic, but similar olivine crystallographic preferred orientations (CPO). (3) The garnet-peridotites have fine-porphyroclastic microstructures. (4) Many coarse-porphyroclastic spinel-peridotites display Fe-enrichment in olivine and pyroxenes, often associated with Ti-enrichment in pyroxenes or spinel and occurrence of modal phlogopite. (5) Equilibrium temperatures and pressures of garnet-peridotites are consistent with a cratonic geotherm, but equilibrium conditions of spinel-peridotites require a warmer geotherm. We interpret these observations as indicating that the xenoliths sample the SFC mantle root, which extends beneath the Brasilia belt, but was modified by reactive transport of the magmas forming the Alto Parnaiba Igneous Province (APIP) between 120 and 90 Ma. The APIP magmatism resulted in heterogeneous modal metasomatism, Fe enrichment, development of coarse-porphyroclastic microstructures in spinel peridotites and fine-porphyroclastic microstructures in garnet-peridotites, and moderate heating of the cratonic mantle root. These changes may produce a decrease in seismic velocities explaining the local weak negative anomaly observed in the lithospheric mantle beneath the APIP, which contrasts with the positive velocity anomalies characterizing the SFC mantle root in P-wave tomography models. However, reactive magma transport did not erase the olivine CPO. Comparison of the average seismic properties of the xenoliths with seismological data implies dominantly subhorizontal fossil flow directions and a non-negligible contribution of the cratonic root to teleseismic S-waves splitting.
DS1998-0196
1998
VaughanCabri, L.J., VaughanModern approaches to ore and environmental mineralogyMineralogical Association of Canada (MAC) Spec. Publishing No. 27, 410p. $ 48.00GlobalBook - table of contents, Ore mineralogy
DS2003-1415
2003
Vaughan, A.P.Vaughan, A.P., Scarrowm J.H.Ophiolite obduction phases as a proxy indicator of superplume events?Earth and Planetary Science Letters, Vol. 213, 3-4, pp. 407-16.MantleTectonics
DS200412-2046
2003
Vaughan, A.P.Vaughan, A.P., Scarrow, J.H.Ophiolite obduction phases as a proxy indicator of superplume events?Earth and Planetary Science Letters, Vol. 213, 3-4, pp. 407-16.MantleTectonics
DS1995-1977
1995
Vaughan, A.P.M.Vaughan, A.P.M.Circum-Pacific mid-Cretaceous deformation and uplift: a superplume relatedevent?Geology, Vol. 23, No. 6, June pp. 491-494Pacific OceanMantle, Superplume, tectonics
DS1996-1475
1996
Vaughan, A.P.M.Vaughan, A.P.M.A Tectonomagmatic model for the genesis and emplacement of Caledonian calc-alkaline lamprophyres. #2Journal of Geological Society, Vol. 153, No. 4, July 1, pp. 613-624.EuropeAlkaline rocks, Lamprophyres
DS1996-1476
1996
Vaughan, A.P.M.Vaughan, A.P.M.A Tectonomagmatic model for the genesis and emplacement of Caledonian calc-alkaline lamprophyres. #1Journal of the Geological Society of London, Vol 133, pp. 613-623.IrelandLamprophyres
DS1998-0423
1998
Vaughan, A.P.M.Ferris, J.K., Vaughan, A.P.M., Storey, B.C.Early break up history of Antarctica recorded by aeromagnetic and satellite gravity data, Weddell Sea.Journal of African Earth Sciences, Vol. 27, 1A, p. 72. AbstractAntarcticaGeophysics - gravity, Tectonics
DS2003-0407
2003
Vaughan, A.P.M.Ferris, J.K., Storey, B.C., Vaughan, A.P.M., Kyle, P.R., Jones, P. C.The Dufek and Forrestal intrusions, Antarctica: a centre for Ferrar large igneousGeophysical Research Letters, Vol. 30, 6, p. 81 DOI 10.1029/2002GLO16719AntarcticaBlank
DS2003-1416
2003
Vaughan, A.P.M.Vaughan, A.P.M., Scarrow, J.H.K rich mantle metasomatism control of localization and initiation of lithospheric strikeTerra Nova, Vol. 15, 3, June pp. 163-169.MantleTectonics, subduction
DS2003-1417
2003
Vaughan, A.P.M.Vaughan, A.P.M., Scarrow, J.H.K rich mantle metasomatism control of localization and initiation of lithospheric strikeTerra Nova, Vol. 15, 3, pp. 163-169.MantleBlank
DS2003-1418
2003
Vaughan, A.P.M.Vaughan, A.P.M., Scarrow, J.H.K rich mantle metasomatism control of localization and initiation of lithospheric strikeTerra Nova, Vol. 15, No. 3, June pp. 163-169.Mantle, GlobalMagmatism - potassic
DS200412-0551
2003
Vaughan, A.P.M.Ferris, J.K., Storey, B.C., Vaughan, A.P.M., Kyle, P.R., Jones, P.C.The Dufek and Forrestal intrusions, Antarctica: a centre for Ferrar large igneous province dike emplacement?Geophysical Research Letters, Vol. 30, 6, p. 81 DOI 10.1029/2002 GLO16719AntarcticaIgneous layered intrusions
DS200412-2047
2003
Vaughan, A.P.M.Vaughan, A.P.M., Scarrow, J.H.K rich mantle metasomatism control of localization and initiation of lithospheric strike slip faulting.Terra Nova, Vol. 15, 3, June pp. 163-169.MantleTectonics, subduction
DS200412-2048
2003
Vaughan, A.P.M.Vaughan, A.P.M., Scarrow, J.H.K rich mantle metasomatism control of localization and initiation of lithospheric strike slip faulting.Terra Nova, Vol. 15, no. 3, June pp. 163-169.MantleMagmatism - potassic
DS200712-1112
2007
Vaughan, A.P.M.Vaughan, A.P.M., Storey, B.C.New supercontinent self destruct mechanism: evidence from the Late Triassic Early Jurassic.Journal of the Geological Society, Vol. 164, 2, pp. 383-392.MantleTectonics
DS1940-0055
1942
Vaughan, B.Newland, D.H., Vaughan, B.Guide to the Geology of the Lake George RegionNew York State Mus. Handbook, No. 19, 234P.United States, Appalachia, New YorkRegional Geology
DS201811-2593
2018
Vaughan, D.G.Martos, Y.M., Jordan, T.A., Catalan, M., Jordan, T.M., Bamber, J.L., Vaughan, D.G.Geothermal heat flux reveals the Iceland hotspot track underneath Greenland.Geophysical Research Letters, Vol. 45, 16, pp. 8214-8222.Europe, Greenlandplumes

Abstract: Heat escaping from the Earth's interior provides important clues about areas of geology and geodynamics. In addition, where a region is covered by an ice sheet, such as Greenland, variations in the heat supplied from the Earth's interior can potentially influence how the ice flows, and hence its future changes. Unfortunately, in ice covered regions direct measurements of heat flow are limited to sparse boreholes, meaning this important quantity is poorly understood. In this study we used variations in the Earth's magnetic field to map out the variations in the amount of heat being supplied to the base of the Greenland Ice Sheet from the Earth's interior. Ice sheet models incorporating these new and improved results will help better constrain future predictions of ice sheet evolution. Overall, the new map not only shows less extreme variations than previous studies, but also reveals a previously unseen band of warmer than expected rock stretching northwest to southeast across Greenland. This band, together with lithospheric models derived from gravity data, is interpreted to be the scar left as the Greenland tectonic plate moved over a region of hot upwelling mantle (the material beneath the tectonic plates), which now underlies Iceland.
DS1990-0753
1990
Vaughan, D.J.Jambor, J.L., Vaughan, D.J.Advanced microcopic studies of ore mineralsMineralogical Association of Canada Short Course Handbook, Vol. 17, 440pBookMicroscopy -ore minerals
DS1990-0754
1990
Vaughan, D.J.Jambor, J.L., Vaughan, D.J.Advanced mircorscopic studies of ore mineralsMineralogical Association of Canada Short Course Handbook, Vol. 17, 440pGlobalBook -table of contents, Microscopy -ore minerals
DS2002-1655
2002
Vaughan, D.J.Vaughan, D.J., Pattrick, R.A.D., Wogelius, R.A.Minerals, metals and molecules: ore and environmental mineralogy in the new milleniumMineralogical magazine, Vol. 66,5, pp. 653-76.EarthEnvironmental
DS200612-0814
2006
Vaughan, M.Li, L.,Weidner, D., Raterron, P., Chen, J., Vaughan, M., Mei, S., Durham, B.Deformation of olivine at mantle pressure using D-DIA.European Journal of Mineralogy, Vol. 18, 1, pp. 7-19.TechnologyExperimental petrology
DS1989-1151
1989
Vaughan, M.T.O'Neill, B., Bass, J.D., Smyth, J.R., Vaughan, M.T.Elasticity of a grossular-pyrope-almandine garnetJournal of Geophysical Research, Vol. 94, No. B12, pp. 17, 819-17, 824GlobalMineralogy, Experimental petrology
DS1994-1895
1994
Vaughan, M.T.Weidner, D.J., Wang, Y., Vaughan, M.T.Strength of diamondScience, Vol.266, No. 5184, Oct. 21, pp. 419-422.GlobalDiamond strength
DS1998-0241
1998
Vaughan, M.T.Chen, J., Inoue, T., Vaughan, M.T.Strength and water weakening of mantle minerals, olivine, wadsleyite andringwoodite.Geophy. Res. Letters, Vol. 25, No. 4, Feb. 15, pp. 575-MantleMineralogy
DS1994-1845
1994
Vaughan, R.A.Vaughan, R.A., Cracknell, A.P.Remote sensing and global climate changeSpringer Verlag, 512p. approx. $ 220.00GlobalRemote sensing, Book -ad
DS1997-1200
1997
Vaughan, S.Vaughan, S.Equity financing and securities regulation in Canada as it affects the Canadian mineral industryDeveloping Indonesia-Canada Cooperation Nov.3-4, Jakarta, 41p. VSE 3p. ASE 4p. TSE 2p. MSE 3p. CDN 3pCanadaLegal - mining laws, policy, Mineral agreement, economics, discoveries
DS1997-1201
1997
Vaughan, S.Vaughan, S.Bulletinet proofing directors of junior resource companies when a discovery ismadeAssaying and Reporting Conference Nov. 10-11, 1997 Singapore, 69p. text, a4, b2, c4, 60p. copies of all slidesOntario, CanadaSampling, assaying, discoveries, Geostatistics, gold, economics, legal
DS1998-1526
1998
Vaughan, S.Vaughan, S.Mineral property valuation and investor concernsPros. Developers Assoc, Short course 90pGlobalBook - table of contents, Reserves, valuations, markets, discoveries, economics
DS1998-1527
1998
Vaughan, S.Vaughan, S., Bourassa, M., Cowan, S.New mining standards guidelines for mining exploration companies listed on the Vancouver Stock ExchangeNatural Resource and Energy Law, Vol. 5, No. 1, March pp. 1-3British ColumbiaLegal - mining law, Stock exchange - Vancouver
DS201112-1083
2011
Vaughan, S.Vaughan, S.Corporate Social Responsibility and the mineral exploration and mining industry.Heenan Blaikie, November 9p.Canada, globalExplanatory - CSR and industry needs
DS1997-1202
1997
Vaughan, W.S.Vaughan, W.S., Bourassa, M.J., Da Matta Ponte, K.Establishing a mineral regime conducive to exploration investmentPros. and dev. Association Canada, March pp. 46-53CanadaLegal - regulatory, Economics - mining
DS1998-1528
1998
Vaughan, W.S.Vaughan, W.S.Due diligence for mine finance projectsThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM)/MIGA Conference Montreal May, text 33pGlobalEconomics, discoveries, reserves, Risks, technical, sampling, political
DS1999-0293
1999
Vaughn, J.D.Harrison, R.W., Hoffman, D., Vaughn, J.D., et al.An example of neotectonism in a continental interior - Thebes Gap, Midcontinent, United States.Tectonophysics, Vol. 305, pp. 399-417.Missouri, Illinois, MidcontinentTectonics, New Madrid Rifting
DS2002-1656
2002
Vaughn, J.D.Vaughn, J.D., Baldwin, J.N., Barron, A.D.Recurrent late Quaternary deformation within the Dexter tectonic zone, Upper Mississippi embayment.16th. International Conference On Basement Tectonics '02, Abstracts, 2p., 2p.MissouriTectonics - Reelfoot rift region
DS1994-1846
1994
Vaughn, W.S.Vaughn, W.S.Financing the Canadian mineral industryCanadian Institute 1994 Canadian Mining Symposium, Preprint, 29pCanadaEconomics, Mining industry -financing
DS201704-0646
2017
Vaupel, E.Schmetzer, K., Gilg, H.A., Vaupel, E.Synthetic emeralds grown by Richard Nacken in the mid-1920's: properties, growth technique, and historical account.Gems & Gemology, Vol. 52, 4, pp. 368-392.Europe, GermanySynthetic - emeralds

Abstract: Chemical and microscopic examination of the first gem-quality synthetic emeralds of facetable size proves that Prof. Richard Nacken grew two main types of emerald by flux methods in the mid-1920s. One of these two types, grown with colorless beryl seeds in molybdenum-bearing and vanadium-free fluxes, has not previously been mentioned in the literature and would appear to be unknown to gemologists. The other main type, which has already been described in gemological publications, was grown from molybdenum- and vanadium-bearing fluxes. In drawing these conclusions, rough and faceted synthetic emeralds produced by Nacken were available for study from two principal sources: the Deutsches Museum in Munich, to which Nacken had donated samples in 1961, and family members who had inherited such crystals. Chemical, morphological, and microscopic properties are given, and circumstances concerning the developmental history of the Nacken production, including the possibility of collaboration with IG Farben (a subject of past speculation), are discussed as well. The latter has recently been elucidated by the discovery of original documents from the IG Farben gemstone plant, preserved in the Archives of the German Federal State of Saxony-Anhalt.
DS202108-1281
2021
Vavadiya, A.Eaton-Magana, S., Renfro, N., Vavadiya, A.Diamond shaped cloud in diamond.Gems & Gemology , Vol. 57, 1, pp. 65-66.Globaldiamond morphology
DS2002-1199
2002
VavAn, I.Paava, J., Kabek, B., Dobe, P., VavAn, I., et al.Tin polymetric sulphide deposits in the eastern part of the Dachang tin field and role of black shales - originMineralium deposita, China, southCopper, sinx, tin, black shales, metallogeny, Deposit - Dachang
DS1995-1793
1995
VavilovSobolev, N.V., Shatskiy, V.S., Vavilov, GoryaynovZircon in high pressure metamorphic rocks in folded regions as a unique container of inclusions.....Doklady Academy of Sciences, Vol. 336, No. 4, Nov., pp. 79-85.Russia, Kokchetau MassifCoesite, diamond, Inclusions
DS2001-0006
2001
VavilovAgashev, A.M., Pokhilenko, McDonald, Takazawa, VavilovA unique kimberlite carbonatite primary association in the Snap lake dyke system: evidence from geochemical..Slave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractNorthwest TerritoriesGeochemistry, geochronology, Slave Craton, Deposit - Snap Lake
DS1990-1388
1990
Vavilov, M.A.Sobolev, N.V., Shatskii, V.S., Vavilov, M.A.Mineralogical indicators of ultrahigh pressure metamorphism in eclogite bearing complex of Kokchetav Massif, USSRInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 890-891RussiaEclogite, Mineralogy -inclusions
DS1990-1389
1990
Vavilov, M.A.Sobolev, N.V., Shatskii, V.S., Vavilov, M.A.Ultra high pressure mineral assemblages of inclusions in garnets, zircon sand clinopyroxenes from Diamondiferous metamorphic rocks, northern Kazakhstan, USSREos, Vol. 71, No. 43, October 23, p. 1707 AbstractRussiaMetamorphic rocks, Diamonds
DS1991-1625
1991
Vavilov, M.A.Sobolev, N.V., Shatskiy, V.S., Vavilov, M.A., Goryainov, S.V.Coesite inclusion in zircon from diamond containing gneisses of KokchetavMassif- lst find of coesite in metamorphic rocks of the USSR. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 321, No. 1, pp. 184-188. # hb124RussiaCoesite, Metamorphic rocks
DS1991-1784
1991
Vavilov, M.A.Vavilov, M.A., Sobolev, N.V., Shatskii, V.S.Micas from diamond bearing metamorphic rocks of northern Kazakhstan.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 319, No. 2, pp. 466-470Russia, KazakhstanMetamorphic rocks, Diamonds
DS1993-1653
1993
Vavilov, M.A.Vavilov, M.A., Sobolev, N.V., Shatskiy, V.S.Micas in diamond bearing metamorphic rocks of northern KazakhstanDoklady Academy of Sciences USSR, Earth Science Section, Vol. 319A, No. 6, Publishing July 1993, pp. 177-182.Russia, KazakhstanMetamorphic rocks
DS1994-1657
1994
Vavilov, M.A.Sobolev, N.V., Shatsky, V.S., Vavilov, M.A., Goryaynov, S.A coesite inclusion in zircon from diamond containing gneiss of Kokchetav:first find coesite in metamorphic rocks of the USSRDoklady Academy of Sciences USSR, Earth Science Section, Vol. 322, No. 1, pp. 123-127.RussiaDiamond inclusions, Coesite
DS1995-1720
1995
Vavilov, M.A.Shatsky, V.S., Sobolev, N.V., Jagoutz, E., Vavilov, M.A.Ultrahigh pressure metamorphic environment of microdiamondsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 512-514.Russia, KazakhstanMetamorphic, Deposit -Kokchetav Massif
DS1995-1721
1995
Vavilov, M.A.Shatsky, V.S., Sobolev, N.V., Vavilov, M.A.Diamond bearing metamorphic rocks of the Kokchetav Massif, NorthernKazakhstan.Cambridge University of Press, pp. 427-455.Russia, KazakhstanMetamorphic rocks, Diamond - Kokchetav Massif
DS2003-0757
2003
Vavilov, M.A.Kuligin, S.S., Malkovets, V.G., Pkhilenko, N.P., Vavilov, M.A., Griffin, W.L.Mineralogical and geochemical characteristics of a unique mantle xenoliths from the8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractRussia, YakutiaMantle geochemistry, Deposit - Udachnaya
DS2003-1091
2003
Vavilov, M.A.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Vavilov, M.A., Clark, D.B..Kimberlites and carbonatites of the Snap Lake King Lake dyke system: structural8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractNorthwest TerritoriesDeposit - Snap Lake, King Lake
DS200412-1561
2003
Vavilov, M.A.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Sobolev, N.V., Mityukhin, S.I., Vavilov, M.A., Yanygin, Y.T.Kimberlites of the Nakyn field, Siberia and the Snap Lake King Lake dyke system, Slave Craton, Canada: a new variety of kimberli8 IKC Program, Session 7, POSTER abstractCanada, Northwest TerritoriesKimberlite petrogenesis Deposit - Snap Lake, King Lake
DS200412-1562
2003
Vavilov, M.A.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Vavilov, M.A., Clark, D.B., Wright, K.J.Kimberlites and carbonatites of the Snap Lake King Lake dyke system: structural setting, petrochemistry and petrology of a uniqu8 IKC Program, Session 7, POSTER abstractCanada, Northwest TerritoriesKimberlite petrogenesis Deposit - Snap Lake, King Lake
DS200812-0003
2008
Vavilov, M.A.Agashev, A.M., Kuligan, S.S., Orihashi, Y., Pokhilenko, N.P., Vavilov, M.A., Clarke, D.Ages of zircons from Jurassic sediments of Bluefish River slope, NWT and the possible age of kimberlite activity in the Lena West property.Doklady Earth Sciences, Vol. 421, 1, pp. 751-754.Canada, Northwest TerritoriesDeposit - Lena West, geochronology
DS200812-0004
2008
Vavilov, M.A.Agashev, A.M., Pokhilenko, N.P., Takazawa, E., McDonald, J.A., Vavilov, M.A., Watanabe, T., Sobolev, N.V.Primary melting sequence of a deep ( >250 km) lithospheric mantle as recorded in the geochemistry of kimberlite carbonatite assemblages, Snap Lake dyke system, Canada.Chemical Geology, Vol. 255, 3-4, pp. 317-328.Canada, Northwest TerritoriesDeposit - Snap Lake
DS201012-0590
2010
Vavilov, M.A.Pokhilenko, N.P., Afanasev, V.P., Vavilov, M.A.Behaviour of kimberlite indicator minerals during the formation of mechanical dispersion halos in glacial settings.Lithology and Mineral Resources, Vol. 45, 4, pp. 324-329.Canada, Northwest TerritoriesDeposit - CL 25
DS201212-0562
2012
Vavilov, M.A.Pokhilenko, N.P., Afanasev, V.P., McDonald, J.A., Vavilov, M.A., Kulgin, S.S., Pokhilenko, L.N., Golovin, A.V., Agashev, A.M.Kimberlite indicator minerals in terrigene sediments of lower part of Mackenzie River Basin, NWT, Canada: evidence of new craton with thick lithosphere.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Northwest TerritoriesGeochemistry - KIMS
DS201312-0034
2012
Vavilov, M.A.Ashchepkov, I.V., Kuligin, S.S., Vavilov, M.A., Vladykin, N.V., Nigmatulina, E.NB., Lkhmelnikova, O.S., Rotman, A.Ya.Characteristic feature of the mantle beneath Kharamai field in comparison with the other regions in Prianabarie.Vladykin, N.V. ed. Deep seated magmatism, its sources and plumes, Russian Academy of Sciences, pp. 226-RussiaGeophysics - seismics
DS201412-0022
2014
Vavilov, M.A.Ashchepkov, I.V., Vladykin, N.N., Ntaflos, T., Kostrovitsky, S.I., Prokopiev, S.A., Downes, H., Smelov, A.P., Agashev, A.M., Logvinova, A.M., Kuligin, S.S., Tychkov, N.S., Salikhov, R.F., Stegnitsky, Yu.B., Alymova, N.V., Vavilov, M.A., Minin, V.A., BabusLayering of the lithospheric mantle beneath the Siberian Craton: modeling using thermobarometry of mantle xenolith and xenocrysts. Tectonophysics, Vol. 634, 5, pp. 55-75.Russia, YakutiaDaldyn, Alakit, Malo-Botuobinsky fields
DS201909-2016
2019
Vavilov, M.A.Ashchepkov, I., Ivanov, A.S., Kostrovitsky, S.I., Vavilov, M.A., Vladykin, N., Babushkina, S.A., Tychkov, N.S., Medvedev, N.S.Mantle terranes of the Siberian craton: their interaction with plume melts based on thermobarometry and geochemistry of mantle xenocrysts.Solid Earth, Vol. 10, 2, pp. 197-245.Russia, Siberiamelting

Abstract: Variations of the structure and composition of mantle terranes in the terminology of the Siberian craton were studied using database (>60000) EPMA of kimberlite xenocrysts from the pipes of Yakutian kimberlite province (YKP) by a team of investigators from IGM, IGH, IEC and IGBM SB RAS and ALROSA company. The monomineral thermobarometry (Ashchepkov et al., 2010, 2014, 2017) Geochemistry of minerals obtained LA ICP MS was used to determine the protolith, melting degree, Type of the metasomatism . The mantle stratification commonly was formed by 6-7 paleosubduction slabs, separated by pyroxenite, eclogite, and metasomatic horizons and dunite lenses beneath kemberltes . We built mantle sections across the kimberlite field and transects of craton. Within the established tectonic terrains strengthening to thousands km (Gladkochub et al, 2006), the collage of microplates was determined at the mantle level. Under the shields of Anabar and Aldan lower SCLM consist of 3 -4 dunites dunites with Gar-Px-Ilm- Phl nests. Terranes framing protocratons like suture Khapchanskyare are saturated in eclogites and pyroxenites, sometimes dominated probably represent the ascending bodies of igneous eclogites intruding mantle lithosphere (ML). The ubiquitous pyroxenite layer at the level of 3.5-4.5 GPa originated in the early Archaean when melted eclogites stoped stoped subdction. Beneath the Early Archaean granite-greenstone terranes - Tunguskaya, Markhinskaya, Birektinskaya, Shary-Zhalgaiskaya (age to~3.8-3.0 GA) (Gladkochub et al., 2018) the SCLM is less depleted and often metasomatized having flat structures in some subterrains. Daldyn and Magan granulite-orthogneisic terranes have a layered and folded ML seen in N-S sections from Udachnaya to Krasnopresnenskaya less pronounced in latitudinal direction. From Daldyn to Alakit field increases the degree of Phl metasomatism and Cpx alkalinity. The most productive Aykhal and Yubleynaya pipes confined to the dunite core. Within the Magan terrane, the thin-layered SCLM have depleted base horizon. Granite-greenstone Markha terrane contains pelitic eclogites. Central and Northern craton parts show slight inclination of paleoslabs to West. The formation of SCLM in Hadean accompanied by submelting (Perchuk et al., 2018, Gerya, 2014.) had no deep roots. Ultrafine craton nuclei like Anabar shield was framed by steeper slab. During 3.8-3.0 GA craton keel growth in superplume periods (Condie, 2004) when melted eclogites and peridotites acquiring buoyancy of the sinking plate melted. For peridotites, the melting lines calculated from the experimental data (Herzberg, 2004) mainly lie near 5-6 GPA (Ionov et al., 2010; 2015). In classical works all geotherms are conductive (Boyd, 1973), but this is quite rare. The garnet pyroxene geotherms for (Ashchepkov et al., 2017) calculated with most reliable methods (Nimis, Taylor, 2000; McGregor , 1974; Brey Kohler, Nickel Green, 1985; Ashchepkov et al., 2010; 2017) give are sub-adiabatic and are formed during the melt percolation superplume vent often in presence of volatiles (Wyllie, Ryabchikov, 2000) and therefore, after superplumes trends P-Fe# of garnet are smoothed and change the tilts.
DS1994-1656
1994
Vavilov, MM.A.Sobolev, N.V., Shatskiy, V.S., Vavilov, MM.A., GoryainoZirconium from metamorphic rocks of folded regions a unique container of inclusions diamond, coesite (Russian)Doklady Academy of Sciences Nauk.(Russian), Vol. 334, No. 4, Feb. pp. 488-492.RussiaMetamorphic rocks, Coesite
DS1982-0616
1982
Vavilov, V.S.Vavilov, V.S., Gippius, A.A., Dravin, V.A., Zajeev, A.M., Zakup.Cathodluminescence of Natural Diamond Associated with Implanted Impurities.Soviet Physics of Semi-conductors, Vol. 16, No. 11, PP. 1288-1290.RussiaBlank
DS1993-1654
1993
Vavra, G.Vavra, G.A guide to quantitative morphology of accessory zirconChemical Geology, Vol. 110, No. 1/3, November 25, pp. 15-28GlobalAlteration, Zircon
DS1991-1561
1991
Vavtlov, M.A.Shatsky, V.S., Sobolev, N.V., Zayachkovsky, A.A., Zorin, Y.M., Vavtlov, M.A.New occurrence of microdiamonds in metamorphic rocks as a proof forDoklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 321, pp. 189-193.Russia, Commonwealth of Independent States (CIS)Microdiamonds, Metamorphic rocks
DS1983-0248
1983
Vayner, D.I.Genshaft, YU.S., Saltykovskiy, A.YA., Vayner, D.I.Crystallization of minerals of the eclogite paragenesis at pressures of 35to 50 kbarDoklady Academy of Science USSR, Earth Science Section, Vol. 273, Nov.-Dec. pp. 115-118RussiaXenoliths, Eclogite
DS1984-0297
1984
Vayner, D.I.Genshaft, YU.S., Saltykovskiy, A.YA., Vayner, D.I.Generation of potassic mantle magma as inferred from experimental petrologic dataDoklady Academy of Science USSR, Earth Science Section, Vol. 275, March-April pp. 53-55RussiaGenesis, Eclogite
DS1985-0230
1985
Vayner, D.I.Genshaft, YU.S., Vayner, D.I., Saltykovskiy.Crystallization of Minerals of Eclogite Paragenesis at Pressures of 35 to 50 Kbar.Doklady Academy of Science USSR, Earth Science Section., Vol. 273, No. 1-6, PP. 115-118.RussiaGarnet, Composition, Diamond Bearing Eclogites
DS1983-0525
1983
Vazhenin, B.P.Prokopchuk, B.I., Shumilov, YU.V., Vazhenin, B.P.Experimental Dat a on Weathering of Kimberlite and its Behavior in Streams.Doklady Academy of Sciences ACAD. NAUK USSR EARTH SCI. SECTION., Vol. 261, No. 1-6, PP. 113-115.RussiaGeochemistry
DS1998-1529
1998
Vdovets, A.Z.Vdovets, A.Z.Epochs of alunite formation in the Earth's historyDoklady Academy of Sciences, Vol. 358, No. 1, pp. 26-29.MantleHistory
DS1960-0892
1967
Vdovykin, G.P.Vdovykin, G.P.Carbon Matter of Meteorites (organic Compounds, Diamonds, Graphite).Moscow: Nauka Publishing, RussiaBlank
DS1970-0207
1970
Vdovykin, G.P.Vdovykin, G.P.Diamonds in Meteorites and KimberlitesGeochemistry International (Geokhimiya)., No. 11, PP. 1373-1380.RussiaBlank
DS1975-1252
1979
Vdovykin, G.P.Vdovykin, G.P., Bodunov, YE.N., et al.Bitumens in the Mir Kimberlite PipeDoklady Academy of Sciences USSR, EARTH SCI. SECTION., Vol. 245, No. 1-6, PP. 206-210.RussiaBlank
DS1998-1530
1998
Vearncombe, J.Vearncombe, J.Geology and exploration potential of southern and eastern AfricaAustralia Ins. Geosci., Bulletin. 25, pp. 9-15.Angola, South Africa, ZimbabweKimberlites, structure control, Deposit - Lucapa Corridor
DS2003-1497
2003
Vearncombe, J.Wormald, R.J., Eckhardt, F.D., Vearncombe, J., Vearncombe, S.Spatial distribution analysis of pans in Botswana: the importance of structural controlSouth Africa Jnournal of Geology, BotswanaBlank
DS200412-2144
2003
Vearncombe, J.Wormald, R.J., Eckhardt, F.D., Vearncombe, J., Vearncombe, S.Spatial distribution analysis of pans in Botswana: the importance of structural control.South African Journal of Geology, Vol. 106, 4, 287-290.Africa, BotswanaStructure, geomorphology
DS1987-0454
1987
Vearncombe, J.R.McCourt, S., Vearncombe, J.R.Shear zones bounding the central zone of the Limpopo mobile belt, SouthernAfricaJournal of Structural Geology, Vol.9, No.2, pp. 127-137South AfricaStructure, Shear
DS1988-0727
1988
Vearncombe, J.R.Vearncombe, J.R.Structure and metamorphism of the Archean Murchison Belt, Kaapvaal South Africa.Tectonics, Vol. 7, No. 4, Aug. pp. 761-774.South AfricaTectonics, Craton - Kaapvaal
DS1988-0728
1988
Vearncombe, J.R.Vearncombe, J.R., Cheshire, P.E., De Beer, J.H., Killick, A.M.Structures related to the Antimony line, Murchison schist belt,Kaapvalcraton, South AfricaTectonophysics, Vol. 154, No. 3/4, November 10, pp. 285-308South AfricaTectonics, Craton
DS1991-0988
1991
Vearncombe, J.R.Libby, J., Groves, D.I., Vearncombe, J.R.The nature and tectonic significance of the crustal scale Koolyanobbing shear zone, Yilgarn Craton, Western AustraliaAustralian Journal of Earth Sciences, Vol. 38, pp. 229-245AustraliaTectonics, Shear zone
DS1991-1785
1991
Vearncombe, J.R.Vearncombe, J.R.A possible Archean Island arc in the Murchison belt, Kaapvaal craton, South AfricaJournal of African Earth Sciences, Vol. 13, No. 3-4, pp. 299-304South AfricaCraton, Island arc
DS2002-1657
2002
Vearncombe, J.R.Vearncombe, S., Vearncombe, J.R.Tectonic controls on kimberlite location, southern AfricaJournal of Structural Geology, Vol. 24, 10, Oct.pp. 1619-25.South Africa, BotswanaTectonics, Kimberlite - spatial analysis (SpaDiS(TM)
DS2002-1657
2002
Vearncombe, S.Vearncombe, S., Vearncombe, J.R.Tectonic controls on kimberlite location, southern AfricaJournal of Structural Geology, Vol. 24, 10, Oct.pp. 1619-25.South Africa, BotswanaTectonics, Kimberlite - spatial analysis (SpaDiS(TM)
DS2003-1497
2003
Vearncombe, S.Wormald, R.J., Eckhardt, F.D., Vearncombe, J., Vearncombe, S.Spatial distribution analysis of pans in Botswana: the importance of structural controlSouth Africa Jnournal of Geology, BotswanaBlank
DS200412-2144
2003
Vearncombe, S.Wormald, R.J., Eckhardt, F.D., Vearncombe, J., Vearncombe, S.Spatial distribution analysis of pans in Botswana: the importance of structural control.South African Journal of Geology, Vol. 106, 4, 287-290.Africa, BotswanaStructure, geomorphology
DS2003-1419
2003
Vearncombe, S. and J.Vearncombe, S. and J.A new paradigm for kimberlite intrusion. Structural corridors....Rough Diamond Review, pp. 29-31. www.roughdiamondreview.com Aus $ 95.South AfricaDiamond genesis, spatial analysis
DS200412-2049
2003
Vearncombe, S.and J.Vearncombe, S.and J.A new paradigm for kimberlite intrusion. Structural corridors.....Rough Diamond Review, pp. 29-31. Aus $ 95.Africa, South AfricaDiamond genesis, spatial analysis
DS1930-0207
1935
Veatch, A.C.Veatch, A.C.Evolution of the Congo BasinGeological Society of America (GSA), Memoir 3, 183p.Angola, Tanzania, Zimbabwe, Southern AfricaCongo Basin, Sedimentology, Stratigraphy, Tectonics
DS1910-0108
1910
Veatch, O.Veatch, O.Two Pages on Diamonds Regards the Hall County Find by Stephenson in 1843 and the Light Find of Clayton County As Authentic.Georgia Min. Res. Bulletin., No. 23, 2P.GlobalDiamond Occurrence
DS1989-0564
1989
Veblen, D.R.Guthrie, G.D., Navon, O., Veblen, D.R.Analytical and transmission electron microscopy of turbid coateddiamondsEos, Vol. 70, No. 15, April 11, p. 510. (abstract.)GlobalMineralogy, Coated diamonds
DS1991-0639
1991
Veblen, D.R.Guthrie, G.D.Jr., Veblen, D.R., Navon, O., Rossman, G.R.Submicrometer fluid inclusions in turbid diamond coatsEarth and Planetary Science Letters, Vol. 105, pp. 1-12Democratic Republic of CongoDiamond morphology, Diamond inclusions
DS1991-0669
1991
Veblen, D.R.Harlow, G.E., Veblen, D.R.Potassium in clinopyroxene inclusions from diamondsScience, Vol. 251, No. 4994, February 8, pp. 652-655GlobalDiamond inclusions, PotassiuM.
DS200712-1113
2006
Vecsei, P.Vecsei, P., Macthans, H., Schryer, R.Monitoring a sub-arctic lake trout population to determine potential TDS effects from a diamond mining operation at Snap Lake.34th Yellowknife Geoscience Forum, p. 59-60. abstractCanada, Northwest TerritoriesWater
DS200612-1094
2006
Vecsey, L.Plomerova, J., Babuska, V., Vecsey, L., Kozlovskaya, E., Raita, T.SSTWG.Proterozoic Archean boundary in the mantle lithosphere of eastern Fennoscandia as seen by seismic anisotropy.Journal of Geodynamics, Vol. 41, 4, May pp. 400-410.Europe, FennoscandiaGeophysics - seismics
DS200412-1902
2004
Vedanti, N.Srivastava, R.P., Chattopadhyay, S., Vedanti, N., Dimri, V.P.Gravity and magnetic studies over the circular geomorphic crater looking structures in the Narmada Traps, central India.Journal Geological Society of India, Vol. 64, 1, pp. 97-102.IndiaGeophysics - gravity, magnetics, Deccan basalts
DS201312-0678
2013
Vedanti, N.Pandey, O.P., Vedanti, N., Srivastava, R.P., Uma, V.Was Archean Dharwar craton ever stable? A seismic perspective.Journal of the Geological Society of India, Vol. 81, 6, pp. 774-780.IndiaGeophysics - seismics
DS201412-0660
2013
Vedanti, N.Pandev, O.P., Srivastava, R.P., Vedanti, N., Dutta, S., Dimri, V.P.Anomalous crustal and lithospheric mantle structure of southern part of the Vindhyan Basin and its geodynamic implications.Journal of Asian Earth Sciences, Vol. 91, pp. 316-328.IndiaGeophysics - seismics
DS1930-0284
1938
Vedder, H.Vedder, H.Southwest Africa in Early TimesLondon: Oxford University Press, 525P.Southwest Africa, NamibiaHistory, Ethnography
DS200512-1131
2005
Vedin, A.T.Vedin, A.T., Vorobev, V.V., Emelyanov, E.L., Makhrachev, A.F., Potashnikov, A.K., Shlyufman, E.M.X ray luminescence diamond separator with digital signal.Journal of Mining Science, Vol. 40, 6, pp. 633-638.Mining -5 + 2mm in size concentrates
DS1998-1531
1998
Veena, K.Veena, K., Paney. Krishnamurthy, Guptalead, Strontium, and neodymium isotopic systematics of the carbonatites of Sung Valley, Meghalaya, implications for plume...Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 1875-84.India, northeastCarbonatite - geochronology, Mantle - plume sources, characteristics
DS201801-0032
2017
VeenakrishnaKrishnamurthy, P., VeenakrishnaCarbonatites of India: part 2. Geochemistry, stable and unstable isotopes and petrogenesis.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 26-28.Indiacarbonatites

Abstract: Geochemically carbonatites and genetically associated alkaline rocks represent an anomalous association of both large-ion lithophile (LIL) elements including the highfield strength (HFS) elements group such as Sr, Ba, Zr, Nb, REE, Y, Sc, Th, and U (excluding Rb) often from trace (< 0.1%) to minor/major components (> 0.1-1%) besides Ca, Mg, Fe, Mn, Si, Ti, Al, P, Na, K and CO2 in major components. Extreme heterogeneity in terms of elemental abundances is in fact a characteristic feature, often at a single outcrop level, in many carbonatite complexes (e.g. Amba Dongar, Sevathur, Sung Valley). Such apparent chemical diversity is related to the mineralogical heterogeneity that is not uncommon in many carbonatite complexes, leading to diverse mineral prefixes in carbonatite types such as apatite-sovite, apatite-magnetite soviet, riebeckite beforsite, silico-carbonatite and numerous other types (e.g. Sevathur, Samalpatti and Pakkanadu). The most diagnostic geochemical character of carbonatites stem from their geochemical features, especially the higher abundances of LIL and HFS elements, often the highest among the diverse igneous rock types as also compared to the primitive mantle or sedimentary or metamorphosed limestone/or marble or calc-silicate rocks. This has been shown from several studies of Indian carbonatites (Krishnamurthy, 1988; Schleicher et. al. 1998 and others). Radiogenic and stable isotopic ratios have been used since the mid 1990’s on Indian carbonatites which range in age from mid Proterozoic to Cretaceous in both rift related settings and associated with large igneous provinces, apparently related to deep mantleplumes, to provide constraints on the evolution of the sub-continental mantle through time. Various mantle reservoirs like HIMU (A mantle source enriched in U and Th believed to be due to recycling of ancient altered oceanic crust into the mantle), DMM (Depleted MORB mantle), EM1 (Enriched Mantle 1, generated either by recycling of lower crustal material or enrichment by mantle metasomatism) and EM2 (Enriched Mantle 2, possibly formed by recycling of continentally derived sediment, or ocean island crust into the mantle by subduction processes) with distinct isotopic signatures in the Sr- Nd-Pb isotopic space have been invoked to explain the observed variations in isotopic ratios in carbonatites worldwide (Zindler and Hart, 1984 and others). Stable isotopes of Indian carbonatites have been comprehensively reviewed by Ray and Ramesh (2009). Based on ?13C and ?18O variations, carbonatites have been grouped by them into: 1. Primary, unaltered ?18O values (5.3-7.5‰) which indicate mantle signatures that ensue from batch crystallization under plutonic conditions, as observed at Hogenakal, Sung Valley and Samchampi. ?13C values, however, appear to be more enriched (-6 to - 3.1‰) than expected for the mantle. Such a feature of enrichment probably happened sometime around ~2.4 Ga, as a sequel to metasomatism by fluids derived from recycled oceanic crust through subduction that carried enriched carbon of lithospheric mantle. 2. Secondary, altered carbonatites’ (e.g. mainly Amba Dongar and others) showing wide variations in ?13C and ?18 O values apparently results from low temperature alteration by either meteoric water or CO2-bearing aqueous fluids. The values of ??Sr (+5.3 to +7.8), ??Nd ( +1.7 to + 2.3) and initial Pb ratios (19.02, 15.67 and 39.0) for the Sung Valley complex and ?Sr (+3.0 to + 9.3) and ?Nd (+0.45 to +2.3) and initial Pb ratios ( 206Pb/204Pb= 19.12, 207Pb/204Pb= 15.66 and 208Pb/204Pb= 39.56) for the Samchampi alkaline complex are well constrained and indicate that they have originated from isotopically similar source regions that are characterised by somewhat higher Rb/Sr ratio relative to bulk earth, minor LREE depletion with respect to CHUR and time integrated enhancement of the U/Pb ratio relative to bulk earth. However, carbonatites from Sirivasan and Amba Dongar (Srivatsava and Taylor, 1996, Simonetti et al., 1995, Ray and Ramesh, 2006) indicate higher values with ?Sr = +14.6 to +21.8, ?Nd = -0.6 to -1.84 and measured 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of 19.0, 15.6 and 39.3 and indicate greater enrichment in terms of higher Rb/Sr ratios and LREE enrichment with respect to CHUR. Differences in the north eastern complexes and western complexes are also seen in the stable isotopic data wherein, data for both Sung Valley and Samchampi are constrained with average values of -3.1 ± 0.1‰ for ?13C and 6.33 ± 0.2‰ and -3.1 ± 0.2‰ for ?13C and 7.34 ± 0.7‰ for ?18O respectively whereas data from Amba Dongar and Sirivasan have ?13C of -2.6 to -8.6 ‰ and ?18O of 7.62 to 26.8 ‰. Heterogeneous mantle source has been proposed for the Hogenakal carbonatites with two groups one having high ??Nd and low ??Sr and the other having low ??Nd and high ??Sr. Carbonatites from Sevattur are more enriched with ??Sr (22 to 23), ??Nd ( -5.1 to -5.7) and ?13C ( -4.8 to -6.2‰) and ?18O (6.7 to 7.6 ‰) (Schleicher et.al., 1996, Pandit., et al. 2016). Petrogenetic models of the different carbonatite complexes are reviewed in the light of geochemical and isotopic characteristics. These include models that invoke mantle plumes of both the Kerguelen (e.g. Sung Valley and Samchampi) and Reunion (e.g. Amba Dongar, Sarnu-Dandali and others related to the Deccan volcanism) and their influence on the subcontinental lithosphere. Enriched mantle sources have been indicated for many of the Proterozoic complexes of Tamil Nadu. Evaluations of the different carbonatite complexes in terms of the three known genetic models, listed as follows, have also been elucidated. These include: (a) Direct partial melts from enriched, carbonatedperidotitic sources; (b. Immiscible carbonate and silicate magma after differentiation of the primary, carbonated peridotitic magma; (c) Extreme stage of differentiation of the ultra-alkaline, nephelinite magma. Such approaches also lead us to understand the temporal evolution of the mantle source regions of carbonatites of India since Palaeoproterozoic times. The petrogenetic link between carbonatite-kimberlite-lamproitelamprophyre in the Indian scenario is also briefly reviewed.
DS200912-0792
2009
Veeraiah, B.Veeraiah, B., Ramadass, G., Himabindu, D.A subsurface criterion for predictive exploration of kimberlites from bouguer gravity in the eastern Dharwar craton, India.Journal of the Geological Society of India, Vol. 74, July pp. 69-77.IndiaMaddur-Narayanpet kimberlite, geophysics
DS201112-1084
2009
Veeraiah, B.Veeraiah, B., Ramadass, G., Himabindu, D.A subsurface criterion for predictive exploration of kimberlites from Bouguer Gravity in the eastern Dharwa craton, India.Journal of the Geological Society of India, Vol. 74, pp. 69-77.IndiaNarayanpet-Irladinne area
DS202010-1870
2020
Veeraich, B.Rama Rao, J.V., Kumar, B.R., Kumar, M., Singh, R.B., Veeraich, B.Gravity of Dharwar craton, southern Indian shield.Journal of Geological Society of India, Vol. 96, 3, pp. 239-249. pdfIndiacraton

Abstract: Dharwar craton (DC), by far the largest geological domain in South Indian Shield, occupying about 0.5 million sq. km area, is well-studied terrain both for regional geoscientific aspects and as part of mineral exploration over several important blocks such as the greenstone belts, ultramafic complexes, granite-gneissic terrain and the Proterozoic sediments of Cuddapah basin. The re-look into regional gravity data offers several insights into nature of crust, sub-divisions within the craton, bedrock geology in the covered areas and mineral potentiality of this ancient and stable crust. The regional gravity profiles drawn across the south Indian region mainly suggest that the area can be divided into five domains as Western Dharwar craton (WDC), Central Dharwar craton (CDC), Eastern Dharwar craton (EDC 1), transitory zone of EDC (EDC 2) and Eastern Ghats mobile belt (EGMB) areas. The Bouguer gravity anomaly pattern also questions some of the earlier divisions like eastern margin of Chitradurga schist belt between the WDC and EDC and the boundary of DC with southern granulite terrain (SGT) as they do not restrict at these main boundaries. In this study, mainly four issues are addressed by qualitative and quantitative analysis of regional gravity data and those revealed significant inferences. (1) A distinct gravity character in central part of south Indian shield area occupying about 60, 000 sq. km, suggests that the transitory crustal block, faulted on both sides and uplifted. This area designated as central Dharwar craton (CDC) is characterized with schist belts having characters of both parts of western and eastern Dharwar craton. This inference also opens up the debate about the boundary between western and eastern parts of the craton. Another significant inference is the extension of major schist belts beneath both Deccan volcanic province (DVP) in northwestern part and Cuddapah basin (CB) in southeastern part. (2) Eastern Dharwar craton is reflected as two distinct domains of different gravity characters; one populated with number of circular gravity lows and a few linear gravity high closures indicative of plutonic and volcanic activity and another domain devoid of these intrusive younger granites or schist belts. (3) Large wave length gravity highs occupying thousands of sq.km area and those not relatable to surface geology in eastern Dharwar craton that may have significance for mineral exploration. (4) Gravity data was subjected to further processing like two dimensional modeling which have yielded insights into crustal architecture beneath the Dharwar craton, crustal scale lineaments, craton-mobile belt contact zone and younger intrusives.
DS2000-0799
2000
Veeraswamy, K.Raval, U., Veeraswamy, K.The radial and linear modes of interaction between mantle plume and continental lithosphere: case study...Journal of Geological Society India, Vol. 56, No. 5, Nov. pp. 525-36.IndiaPlumes, dynamics, structures
DS2003-1134
2003
Veeraswamy, K.Raval, U., Veeraswamy, K.India Madagascar separation: break up along a pre-existing mobile belt and chipping ofGondwana Research, Vol. 6, 3, pp. 467-86.Madagascar, IndiaTectonics
DS200412-1633
2003
Veeraswamy, K.Raval, U., Veeraswamy, K.India Madagascar separation: break up along a pre-existing mobile belt and chipping of the craton.Gondwana Research, Vol. 6, 3, pp. 467-86.Africa, MadagascarTectonics
DS200512-1132
2005
Veeraswamy, K.Veeraswamy, K., Harinarayana, T.Electrical signatures due to thermal anomalies along mobile belts reactivated by the trail and outburst of mantle plume: evidences from the Indian subcontinent.Journal of Applied Geophysics, In pressIndiaGeophysics - geodynamics, geothermometry
DS200512-1133
2005
Veeraswamy, K.Veeraswamy, K., Raval, U.Remobilization of the palaeoconvergent corridors hidden under the Deccan trap cover and some major stable continental region earthquakes.Current Science, Vol. 89, 3, August 10, pp. 522-530.IndiaGeophysics - seismics, tectonics
DS200612-1473
2006
Veeraswamy, K.Veeraswamy, K., Harinarayana, T.Electrical signatures due to thermal anomalies along mobile belts reactivated by the trail and outburst of mantle plume: evidence from the Indian subcontinent.Journal of Applied Geophysics, Vol. 58, 4, April, pp. 313-320.IndiaGeodynamics, geothermometry
DS201112-0847
2011
Veeraswarmy, K.Raval, U., Veeraswarmy, K.Mapping of tectonic corridors through hidden parts of the greater Dharwar terrane.Journal of Asian Earth Sciences, Vol. 42, 6, pp. 1210-1225.IndiaGeophysics - seismics, tectonics
DS200412-2050
2004
Veerswamy, K.Veerswamy, K., Raval, U.Chipping of cratons and breakup along mobile belts of a supercontinent.Earth Planets and Space, Vol. 56, 5, pp.491-500. IngentaIndiaMantle plume, lithosphere, tectonomagmatism
DS1989-1544
1989
Veevers, J.J.Veevers, J.J.Middle/late Triassic (230 +-5Ma) sigularity in the stratigraphic and magmatic history of the Pangean heat anomalyGeology, Vol. 17, No. 9, September pp. 784-787China, Australia, AfricaPangea, Stratigraphy
DS1990-1506
1990
Veevers, J.J.Veevers, J.J.Antarctica-Australia fit resolved by satellite mapping of oceanic fracturezonesAustralian Journal of Earth Sciences, Vol. 37, No. 2, June pp. 123-126AntarcticaTectonics, Remote Sensing
DS1991-1786
1991
Veevers, J.J.Veevers, J.J., Li, Z.X.Review of seafloor spreading around Australia II. Marine magnetic anomaly modelling.Australian Journal of Earth Sciences, Vol. 38, No.4 pp. 391-408.AustraliaGeosphysics - magnetics, Tectonics
DS1991-1787
1991
Veevers, J.J.Veevers, J.J., Powell, C.M., Roots, S.R.Review of seafloor spreading around Australia: 1. synthesis of patterns ofspreading.Australian Journal of Earth Sciences, Vol. 38, No. 4, pp. 373-89.AustraliaTectonics, arcs
DS1992-1600
1992
Veevers, J.J.Veevers, J.J.Phanerozoic earth history of AustraliaClarendon Press, Oxford, 420pAustraliaBook -table of contents, Tectonics, paleoclimates
DS1994-1847
1994
Veevers, J.J.Veevers, J.J., Powell, C.McA.Permian-Triassic Pangean basins and foldbelts along the Panthalassan Margin of GondwanalandGeological Society of America, Memoir 184, 372pBook -ad, Basins, sedimentation
DS1995-1978
1995
Veevers, J.J.Veevers, J.J.Emergent, long lived Gondwanaland vs submergent short lived Eurasia:supercontinental and Pan-African heat..Geology, Vol. 23, No. 12, Dec. pp. 1131-1134GlobalMafic underplating, Crust -structure, lower
DS1995-1979
1995
Veevers, J.J.Veevers, J.J., Tewari, R.C.Gondwana master basin of peninsular India between Tethys and the interior of the Gondwanaland -PangeaGeological Society of America, Memoir, No. 187, 75pIndiaPangean tectonics and stratigraphy, Table of contents
DS1997-1203
1997
Veevers, J.J.Veevers, J.J., Walter, M.R., Scheibner, E.Neoproterozoic tectonics of Australia- Antarctica and Laurentia and the 560Ma birth of Pacific Ocean ...Journal of Geology, Vol. 105, No. 2, March pp. 225-242.GlobalPangean supercycle, Tectonics
DS1998-1532
1998
Veevers, J.J.Veevers, J.J.Tectonic controls of Gondwana and the Gondwanian faciesJournal of African Earth Sciences, Vol. 27, 1A, p. 203. AbstractGondwanaTectonics
DS2000-0977
2000
Veevers, J.J.Veevers, J.J.Billion year earth history of AustraliaGemoc Press, 388p.AustraliaLithosphere - tectonics
DS2003-1420
2003
Veevers, J.J.Veevers, J.J.Pan-African is Pan-Gondwanaland: oblique convergence drives rotation during 650-Geology, Vol. 31, 6, June pp. 481-4.South AfricaBlank
DS200412-2051
2003
Veevers, J.J.Veevers, J.J.Pan-African is Pan-Gondwanaland: oblique convergence drives rotation during 650- 500 Ma assembly.Geology, Vol. 31, 6, June pp. 481-4.Africa, South AfricaTectonics
DS200512-1134
2004
Veevers, J.J.Veevers, J.J.Gondwanaland from 650-500 Ma assembly through 320 Ma merger in Pangea to 185-100 Ma.Earth Science Reviews, Vol. 68, 1-2, pp. 1-132.GondwanaTectonics, paleoreconstruction
DS200612-1474
2006
Veevers, J.J.Veevers, J.J.Edge tectonics (trench rollback, terrane export) of Gondwanaland-Pangea synchronized by supercontinental heat.Gondwana Research, Vol. 8, 4, pp. 449-456.MantleTectonics
DS200612-1475
2006
Veevers, J.J.Veevers, J.J., Belousova, E.A., Saced, A., Sircombe, K., Cooper, A.F., Read, S.E.Pan-Gondwanaland detrital zircons from Australia analyzed for Hf isotopes and trace elements reflect an ice covered Antartic provenance 700-500 Ma alkalinityEarth Science Reviews, in press,AustraliaGeochronology, trace elements
DS200612-1476
2006
Veevers, J.J.Veevers, J.J., Belousova, E.A., Saeed, A., Sircombe, K., Cooper, A.F., Read, S.E.Pan Gondwanaland detrital zircons from Australia analysed for Hf isotopes and trace elements reflect an ice covered Antarctic provenance of 700-500 Ma ...Earth Science Reviews, Vol. 76, 3-4, June pp. 135-174.AustraliaGeochronology, alkaline affinity
DS200712-1114
2007
Veevers, J.J.Veevers, J.J.Pan-Gondwanaland post-collisional extension marked by 650-500 Ma alkaline rocks and carbonatites and related detrital zircons: a review.Earth Science Reviews, Vol. 83, 1-2, pp. 1-47.GlobalCarbonatite
DS200712-1115
2007
Veevers, J.J.Veevers, J.J.Pan-Gondwanaland and post collisional extension marked by 650-550 and carbonatites and related detrital zircons: a review.Earth Science Reviews, In press availableGondwanaCarbonatite
DS201212-0753
2012
Veevers, J.J.Veevers, J.J.Reconstructions before rifting and drifting reveal the geological connections between Antarctica and its conjugates in Gondwanaland.Earth Science Reviews, Vol. 111, 3-4, pp. 249-318.GondwanaTectonics
DS1993-0465
1993
Vega, V.Freymueller, J.T., Kellogg, J.N., Vega, V.Plate motions in the North Andean regionJournal of Geophysical Research, Vol. 98, No. B 12, Dec. 10, pp. 21, 853-863AndesTectonics, Columbia-Ecuador subduction system
DS201906-1358
2019
Veglio, C.Veglio, C., Lawley, C., Kjarsgaard, B., Pearson, D.G.Behaviour of ore forming elements in the subcontinental lithospheric mantle below the Slave craton.GAC/MAC annual Meeting, 1p. Abstract p. 187.Canada, Northwest Territoriesdeposit - Jericho, Muskox

Abstract: The fertility of the subcontinental lithospheric mantle as source for metal-rich magmas remains poorly understood. We report new major (EPMA), minor and trace element (LA-ICP-MS) results for olivine mantle xenocrysts sourced from the Jurassic age Jericho, Muskox and Voyageur kimberlites, western Nunavut in the Slave Craton, approximately 30 km north of the Lupin gold mine. Target elements include a suite of ore-forming elements that are unconventional for mantle petrology studies, but may represent important geochemical tracers for metal metasomatism. Using single-grain aluminum-in-olivine thermometry, formation temperatures for the olivine grains were calculated and projected on to a mantle geotherm to estimate PT conditions. The suite of xenocrysts corresponds to mantle sampling between 100-190 km depth. Their range in Mg# indicates that all 3 kimberlites sampled variably depleted mantle peridotite. The patterns of trace element enrichments found are consistent with those documented previously for mantle olivine xenocryst samples from the lithosphere below the Superior Craton in Kirkland Lake, Ontario. In both studies, some ore-forming elements were found to partition into mantle silicates more at the higher temperatures and pressure prevalent at the base of the lithospheric mantle, notably copper, with concentrations varying from ~ 1 ppm in shallow samples up to 11 ppm at the maximum depth sampled. Because the concentration of metals in melt-depleted lithospheric peridotite is expected to be low (< 20 ppm Cu), mantle silicates likely become a significant host for some ore elements at depth. Highly incompatible high field strength elements yield decreasing concentrations with depth, possibly the result of mantle metasomatic processes. Fluid metasomatized mantle peridotite domains are also inferred from olivine xenocrysts that yield unexpected trace element concentrations (ppb to ppm) for other highly incompatible ore-elements (e.g. As, Mo). We expect that some of these fluid-mobile and highly incompatible ore-elements represent trapped fluid and/or melt inclusions.
DS202205-0726
2022
Veglio, C.Veglio, C., Lawley, C.J.M., Kjarsgaard, B., Petts, D., Pearson, G., Jackson, S.E.Olivine xenocrysts reveal carbonated mid-lithosphere in the northern Slave craton.Lithos, 10.1016/j.lithos.2022.106633, 14p. PdfCanada, Northwest Territoriesolivine

Abstract: The cold, rigid, and melt-depleted mantle underlying Archean cratons plays an important role in the preservation of the overlying continental crust and is one of the main sources of diamonds. However, with the possible exception of rare earth elements (REE) and platinum group-elements (PGE), the concentrations and host mineral phases for many other critical trace elements within lithospheric mantle remain very poorly understood. Here we address that knowledge gap, presenting new electron microprobe and laser-ablation inductively-coupled-plasma mass-spectrometry results for a suite of mantle xenoliths (n = 12) and olivine xenocrysts (n = 376) from the Jericho, Muskox, and Voyageur kimberlites (northern Slave craton, Canada). Low-temperature (<1000 °C) harzburgite xenoliths and olivine xenocrysts suggest that the shallowest portions of the garnet-bearing mantle (?160 km) underlying the northern Slave craton is chemically depleted and becomes increasing re-fertilized from 160 to 200 km. High-temperature (>1000 °C) garnet and clinopyroxene crystals with Ti/Eu ratios > > 1000, and olivine xenocrysts suggest that interaction with ultramafic silicate melts is the most likely mechanism to re-fertilize melt-depleted peridotite with incompatible elements toward the base of the lithosphere (~200 km). In contrast, lower temperature garnet and clinopyroxene with Ti/Eu ratios <1000 are more likely related to metasomatism by carbonatitic melts and/or fluids. Carbonatitic metasomatism is also interpreted as the preferred explanation for the trend of Nb (4 ppm)- and Ta (185 ppb)-rich concentrations of olivine xenocrysts sampled from mid-lithosphere depths (~140 km). With the exception of a few elements that substitute into the olivine crystal structure during sub-solidus re-equilibration (e.g., Ca, Cr, Cu, Na, Sc, V, Zn), most other olivine-hosted trace elements do not systematically vary with depth. Instead, we interpret olivine-hosted trace element concentrations that are significantly above the analytical detection and/or quantification limits to reflect trapped fluid (e.g., As, Mo, Sb, Sn), base-metal sulphide (e.g., Ag, Au, Bi, Pd, Pt, Se, Te), and other mineral inclusions (e.g., U, Th) rather than enrichments of these elements due to substitution reactions or analytical artefacts. We interpret that these inclusions occur in olivine throughout the garnet stability field, but are relatively rare. As a result, these trapped carbonatitic, proto-kimberlite, and/or other ultramafic silicate melts do not represent a significant source for the suite of trace elements that become enriched to economic levels in the crust.
DS201712-2733
2017
Veglio, E.Ugalde, H., Furlan, A., Veglio, E., Milkereit, B., Mirza, A.M., Elliott, B.Airborne MAG/EM dat a integration of Slave Province kimberlites, Northwest Territories.45th. Annual Yellowknife Geoscience Forum, p. 82 abstractCanada, Northwest Territoriesgeophysics

Abstract: As part of the Slave Province Geophysical, Surficial Materials and Permafrost Study, the Northwest Territories Geological Survey (NTGS) commissioned high resolution geophysical surveys in the Slave Geological Province (SGP). The high resolution aeromagnetic survey was flown from February to April 2017 and comprise 87,600 line-km of data flown at 100 m line spacing and nominal aircraft terrain clearance was 60 m with drape flying over the Central Slave craton block. The horizontal gradient magnetic and frequency domain EM (FDEM) survey was flown from February to March 2017 acquired at 75 m line spacing over 6 other blocks with nominal terrain clearance of 60 m to maintain bird height of 25 m, covering 4,580 line-km (Munn Lake, Margaret Lake, Zyena Lake, Lac de Gras West, Big Blue and Mackay Lake). The objective of this work is to develop multi-parameter models to help mineral exploration and mining companies better understand the range of geophysical signatures associated with kimberlites in the SGP. A regular geophysical-based approach for kimberlite exploration usually involves inverting geophysical data with limited geological input. In this contribution we present different ways of looking at the geophysical data and try to obtain a more thorough geological understanding out of it. The workflow starts with a complete GIS compilation of all the ancillary data available in the area: previous industry reports, geology, remote sensing, topographic layers. Secondly, we compute a number of interpretation sub-products from the total magnetic intensity data (tilt derivatives, analytic signal, and other edge detection routines). The next stage involves the computation of a susceptibility distribution from the FDEM data (Tschirhart et al, 2015). With this we are able to generate a magnetic model of the near surface susceptibility distributions, which are then subtracted from the observed data. The resultant map shows anomalous sources that could be associated to either remanent magnetization and/or deeper sources. Following the work of Sterritt (2006), post-emplacement alteration is ubiquitous in kimberlite pipes. Alteration results in production of secondary oxide minerals and alteration of primary oxide minerals to phases with different magnetic susceptibilities (e.g. non-magnetic iron oxides). This can lead to a dramatic increase of magnetic susceptibility due to serpentinization (Clark, 1997). On the other hand, remanent magnetization can change the polarity of the observed magnetic anomalies or even completely remove the expected signature due to an equal but opposite combination of remanent and induced magnetic components. Therefore, a thorough compilation of petrophysical and mineralogical data over kimberlites and altered rocks in the vicinity of known occurrences is critical for the geological understanding of the existing geophysical data. This contribution will show some preliminary processing and compilation work completed over the Slave province kimberlites using the newly acquired geophysical data.
DS1975-0427
1976
Veguni, A.T.Veguni, A.T., Gevorkyan, R.G., Palandzhyan, S.A.Certain Geologic Tectonic Hypotheses of the Diamond Bearing capacity of Alpine Type Ultramafics of Armenia.Izd. Vyssh. Uchebn. Zaved. Geol. I Razv., No. 3, PP. 103-106.Russia, ArmeniaGenesis, Kimberlites
DS1990-1507
1990
Veichow C. JuanVeichow C. JuanPetrogenetic evolution of eclogiteProceedings of the Geological Society of China, Vol. 33, No. 3, July pp. 167-175ChinaEclogite, Mantle, in-situ
DS1990-1508
1990
Veichow C. JuanVeichow C. JuanEclogite shell in the upper mantle of the earthProceedings of the Geological Society China, Vol. 33, No. 4, pp. 329-338ChinaMantle, Eclogite
DS2002-1658
2002
Veiga, M.M.Veiga, M.M., Hinton, J.J.Abandoned artisanal gold mines in the Brazilian Amazon: a legacy of mercury pollutionNatural Resources Forum, Vol.26,1,pp. 15-26.BrazilGold - mining, pollution, environment
DS2001-0551
2001
Veiga, Pangaro. CopelandJordan, T.E., Burns, Veiga, Pangaro. Copeland, MpodozisExtension and basin formation in the southern Andes caused by increased convergence rate: a mid-Cenozoic...Tectonics, Vol. 20, No. 3, June, pp. 308-24.AndesTectonics - not specific to diamonds
DS202009-1671
2020
Veikkolainen, T.Tiira, T., Janik, T., Skrzynik, T., Komminaho, K., Heinonen, A., Veikkolainen, T., Vakeva, S., Korja, A.Full scale crustal interpretation of Kokkola-Kymi ( KOKKY) seismic profile, Fennoscandian shield.Pure and Applied Geophysics, Vol. 177, 8, pp. 3775-3795. pdfEurope, Finlandgeophysics - seismics

Abstract: The Kokkola-Kymi Deep Seismic Sounding profile crosses the Fennoscandian Shield in northwest-southeast (NW-SE) direction from Bothnian belt to Wiborg rapakivi batholith through Central Finland granitoid complex (CFGC). The 490-km refraction seismic line is perpendicular to the orogenic strike in Central Finland and entirely based on data from quarry blasts and road construction sites in years 2012 and 2013. The campaign resulted in 63 usable seismic record sections. The average perpendicular distance between these and the profile was 14 km. Tomographic velocity models were computed with JIVE3D program. The velocity fields of the tomographic models were used as starting points in the ray tracing modelling. Based on collected seismic sections a layer-cake model was prepared with the ray tracing package SEIS83. Along the profile, upper crust has an average thickness of 22 km average, and P-wave velocities (Vp) of 5.9-6.2 km/s near the surface, increasing downward to 6.25-6.40 km/s. The thickness of middle crust is 14 km below CFGC, 20 km in SE and 25 km in NW, but Vp ranges from 6.6 to 6.9 km/s in all parts. Lower crust has Vp values of 7.35-7.4 km/s and lithospheric mantle 8.2-8.25 km/s. Moho depth is 54 km in NW part, 63 km in the middle and 43 km in SW, yet a 55-km long section in the middle does not reveal an obvious Moho reflection. S-wave velocities vary from 3.4 km/s near the surface to 4.85 km/s in upper mantle, consistently with P-wave velocity variations. Results confirm the previously assumed high-velocity lower crust and depression of Moho in central Finland.
DS200512-0702
2005
Veilette, J.J.McClenaghan, M.B., Veilette, J.J.Surficial geology: ice flow indicators for the New Liskeard Temagami area, Ontario.Geological Survey of Canada Open File, No. 3385, 1 cd $ 25.Canada, OntarioGeomorphology
DS201312-0229
2013
Veilette, J.J.Dube-Loubert, H., Roy, M., Allard, G., Lamothe, M., Veilette, J.J.Glacial and nonglacial events in the eastern James Bay lowlands, Canada.Canadian Journal of Earth Sciences, Vol. 50, 4, pp. 379-396.Canada, Ontario, QuebecGeomorphology
DS1986-0831
1986
Veillette, J.J.Veillette, J.J.Former southwesterly ice flows in the Abitibi Timiskaming region:implications for the configuration of the late Wisconsi nan ice sheet.Canadian Journal of Earth Sciences, Vol. 23, pp. 1724-41.Ontario, James Bay LowlandsGeomorphology, glacial
DS1995-1204
1995
Veillette, J.J.McClenaghan, M.B., Veillette, J.J., Dilabio, R.N.W.Ice flow indicators in the Timmins and Kirkland Lake areas, northeasternOntario.Geological Survey of Canada Open File, No. 3014, 1 map colour and i disk $ 40.00OntarioGeomorphology, Ice flow Kirkland Lake area
DS1995-1980
1995
Veillette, J.J.Veillette, J.J.New evidence for northwestward glacial ice flow, James Bay region, QuebecGeological Survey of Canada, Paper 1995-C, pp. 249-258.QuebecGeomorphology, Ice flow
DS1995-1981
1995
Veillette, J.J.Veillette, J.J., McClenaghan, M.B.The sequence of ice flow in Abitibi-Timiskaming: implications for mineral exploration and dispersal...Geological Survey of Canada, Open file, No. 3033, $ 27.00 1 map 1:500, 000Quebec, OntarioMap, Geomorphology -ice flow
DS1995-1982
1995
Veillette, J.J.Veillette, J.J., Roy, M.The spectacular cross striated outcrops of James Bay, QuebecGeological Survey of Canada, Paper 1995-C, pp. 243=248.QuebecGeomorphology, Ice flow
DS1999-0768
1999
Veillette, J.J.Veillette, J.J., Giroux, J.F.The enigmatic rings of the James Bay Lowland, Ontario and Quebec: aprobable geological origin.Geological Survey of Canada (GSC), Open file 3708 $ 12.00Ontario, QuebecStructure, Rings
DS2001-0750
2001
Veillette, J.J.McClenaghan, M.B., Veillette, J.J.Ice flow indicators for the New Liskard - Temagami area, Ontario. NTS 31L,M, 41 I-P.Geological Survey of Canada (GSC) Open File, No. 3385, 1 map 1: 100,000 $ 20.Ontario, Kirkland LakeGeochemistry - sampling, Geomorphology
DS201603-0428
2015
Veira, F.Veira, F.Study of heavy minerals of the Bauru Group.Thesis, , 43p. Pdf *** in PortugueseSouth America, BrazilAlluvials, diamonds
DS1991-1788
1991
Veira, N.Jr.Veira, N.Jr.A new method to evaluate fractional crystallization in igneous rocksJournal of Geology, Vol. 99, pp. 879-885GlobalIgneous rocks, Rayleigh Law -trace elements
DS201910-2294
2019
Veira Conceicao, R.Reis Jalowitski, T.L., Grings Cadeno, D., Veira Conceicao, R., Dalla Costa, M.M., Carvalho, A.M.G., Noqueira Neto, J.D.A.Are Juina diamonds, Super Deep diamonds?Goldschmidt2019, 1p. AbstractSouth America, Brazildeposit - Juina

Abstract: Super Deep Diamonds (SDD) are known to form at depths between ~300 and ~1000 km in the Earth’s mantle [1]. These diamonds as well as their minerals, melts and fluid inclusions are rare natural materials from deep Earth. The aim of this study is to indentify and characterize mineral inclusions in diamonds from Juína, Mato Grosso, Brazil, and hence classify them as SDD (or not). Twelve diamonds from four different mining sites of Juína were selected according to their inclusions using an Estereo Microscope. The main diamond features were based on crystallographic faces, shape, degrees of resportion, crystal state and intergrowing [2]. Diamond samples are transparent, colorless and present octahedro, octahedro-tetrahexahedral and tetrahexahedral habits. Some diamonds show trigons with positive and negative relief, and hexagons with negative relief. Four diamonds are heavily resorbed and were classified as "unknowing habits", as their shapes are distorced and fragmented. Moreover, three samples show abrasion on the vertices of the quartenary axes, and the others have distinct degrees of resorption. Some crystals present intergorwth, such as contact twins (macle) in {111} or aggregates. All diamonds have mineral inclusions of different colors. Most inclusions are black and could be carbon spots, oxides or even silicates, such as olivine. Other inclusions are yellow to red, which might indicate garnet. In addition, blue inclusions were observed, and could be sulphides. The next steps consists of Fourier Transform Infrared (FTIR) to determine diamond nitrogen impurities, and Micro-Raman spectroscopy and X-Ray Diffraction analyses using Synchrotron radiation to determine in situ the chemical composition of mineral inclusions.
DS1997-0305
1997
Veitch, S.East, J., Lambert, I., Wood, P., Veitch, S.Recent trends in access to Australian mineral resourcesAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 4, June pp. 84-88AustraliaBrief overview, Resources, discoveries, economics
DS1960-0756
1966
Veith, K.F.Veith, K.F.A Geophysical Study of a Portion of the Midcontinent Gravity High.Msc Thesis, University Minnesota., GlobalMid-continent, Geophysics
DS1994-0497
1994
VeizerEvans, N.J., Gregoire, D.C., Goodfellow, W.D., Miles, N., VeizerThe Cretaceous Tertiary fireball layer, ejecta layer and coal seam: platinum group elements (PGE) content and mineralogy of size fractionsUnknown, pp. 223-235Alberta, Italy, New Zealand, Denmark, Colorado, WyomingPlatinum Group Elements, K-T boundary
DS1989-1545
1989
Veizer, J.Veizer, J., Hoefs, J., Lowe, D.R., Thurston, P.C.Geochemistry of Precambrian carbonates. 2. Archean greenstone belts and Archean sea waterGeochimica et Cosmochimica Acta, Vol. 53, No. 4, April pp. 859-872. Database # 17926GlobalGeochemistry, Greenstone Belts, Precambrian
DS1989-1546
1989
Veizer, J.Veizer, J., Hoefs, J., Ridler, R.H., Jensen, L.S., Lowe, D.R.Geochemistry of Precambrian carbonates. 1. Archean hydrothermal systemsGeochimica et Cosmochimica Acta, Vol. 53, No. 4, April pp. 845-858. Database # 17926GlobalGeochemistry, Precambrian
DS1989-1547
1989
Veizer, J.Veizer, J., Laznicka, P., Jansen, S.L.Mineralization through geologic time: recycling perspectiveAmerican Journal of Science, Vol. 289, April pp. 484-524. Database # 17843GlobalMetallogeny, Review -Recycling
DS1992-1601
1992
Veizer, J.Veizer, J.Atmospheric evolution: life and the rock cycleNature, Vol. 359, No. 6396, October 15, pp. 587GlobalOrigin of life, Atmosphere
DS1992-1602
1992
Veizer, J.Veizer, J., Bell, K., Jansen, S.L.Temporal distribution of carbonatitesGeology, Vol. 20, No. 12, December pp. 1147-1149.MantleCarbonatite, Distribution
DS1996-1477
1996
Veizer, J.Veizer, J., Ernst, R.E.Temporal pattern of sedimentation Phanerozoic of North AmericaGeochemistry International, Vol. 33, No. 5, pp. 64-76.North America, Canada, United StatesGeochemistry, sediment recycling
DS1996-1478
1996
Veizer, J.Veizer, J., Ernst, R.E.Temporal pattern of sedimentation: Phanerozoic of North AmericaGeochemistry International, Vol. 33, No. 5, pp. 64-76United States, CanadaSedimentology, Geochemistry
DS2001-0393
2001
Veizer, J.Godderis, Y., Francois, L.M., Veizer, J.The early Paleozoic carbon cycleEarth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 181-96.MantleCarbon cycle
DS2002-1554
2002
Veizer, J.Steuber, T., Veizer, J.Phanerozoic record of plate tectonic control of seawater chemistry and carbonate sedimentation.Geology, Vol. 30, 12, pp. 1123-26.GlobalTectonics - not specific to diamonds
DS200512-1135
2005
Veizer, J.Veizer, J.Celestrial climate driver: a perspective from four billion years of the carbon cycle.Geoscience Canada, Vol. 32, 1, March pp. 13-28.Climate models
DS200712-0108
2007
VekemansBrenker, F.E., Vollmer, Vincze, Vekemans, Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200612-0171
2006
Vekemans, B.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, A., Janssens, K., Szaloki, I., Nasdala, L., Joswig, W., Kaminsky, F.CO2 recycling to the deep convecting mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleConvection
DS200712-0106
2007
Vekemans, B.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200712-0107
2007
Vekemans, B.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS201112-0961
2011
Vekemans, B.Silversmit, G., Vekemans, B., Appel, K., Schmitz, S., Schoonjans, T., Brenker, F.E., Kaminsky, F., Vincze, L.Three dimensional Fe speciation of an inclusion cloud within an ultradeep diamond by confocal u-x-ray absortion near edge structure: evidence for late stageAnalytical Chemistry, Vol. 83, pp. 6294-6299.South America, Brazil, Mato GrossoJuina, Rio Soriso, diamond overprint
DS201412-0668
2014
Vekemans, B.Pearson, D.G., Brenker, F., Nestola, F., McNeil, J., Nasdala, L., Hutchison, M., Mateev, S., Mather, K., Silversmit, G., Schmitz, S., Vekemans, B., Vinczw=e, L.A hydrous mantle transition zone indicated by ring woodite included within diamond.Goldschmidt Conference 2014, 1p. AbstractMantleDiamond inclusion
DS201412-0669
2014
Vekemans, B.Pearson, D.G., Brenker, F.E., Nestola, F., McNeill, J., Nasdala, L., Hutchinson, M.T., Mateev, S., Mather, K., Silversmit, G., Schmitz, S., Vekemans, B., Vincze, L.Hydrous mantle transition zone indicated by ring woodite included in diamond.Nature, Vol. 507, March 13, pp. 221-224.Mantle, South America, Brazil, Mato GrossoDiamond inclusion - water storage capacity, magmatism
DS200712-0468
2007
Vekilov, Y.K.Isaev, E.I., Skorodumova, N.V., Ahuja, R., Vekilov, Y.K., Johansson, B.Dynamical stability of Fe-H in the Earth's mantle and core regions.Proceedings of National Academy of Sciences USA, Vol. 104, 22, pp. 9168-9177. IngentaMantleChemistry
DS1997-1204
1997
Veklser, I.Veklser, I., Keppler, H.Experimental studies of the immiscibility between carbonatitic melt and aqueous fluid.Geological Association of Canada (GAC) Abstracts, GlobalCarbonatite
DS201112-1120
2011
VekslerWorgard, L., Trumbell, Keiding, Veksler, Wiedenbeck, Wenzel, MarklF, Cl, and S contents of olivine hosted melt inclusions from picritic dike rocks, Etendeka, NW Namibia.Goldschmidt Conference 2011, abstract p.2177.Africa, NamibiaPicrite
DS201602-0242
2016
Veksler, H.V.Song, WL., Xu, C., Veksler, H.V., Kynicky, J.Experimental study of REE, Ba, Sr, Mo and W partitioning between carbonatitic melt and aqueous fluid with implications for rare metal mineralization.Contributions to Mineralogy and Petrology, Vol. 171, 12p.MantleCarbonatite

Abstract: Carbonatites host some unique ore deposits, especially rare earth elements (REE). Hydrothermal fluids have been proposed to play a significant role in the concentration and transport of REE and other rare metals in carbonatites, but experimental constraints on fluid-melt equilibria in carbonatitic systems are sparse. Here we present an experimental study of trace element (REE, Ba, Sr, Mo and W) partitioning between hydrous fluids and carbonatitic melts, bearing on potential hydrothermal activity associated with carbonatite ore-forming systems. The experiments were performed on mixtures of synthetic carbonate melts and aqueous fluids at 700-800 °C and 100-200 MPa using rapid-quench cold-seal pressure vessels and double-capsule assemblages with diamond traps for analyzing fluid precipitates in the outer capsule. Starting mixtures were composed of Ca, Mg and Na carbonates spiked with trace elements. Small amounts of F or Cl were added to some of the mixtures to study the effects of halogens on the element distribution. The results show that REE, Ba, Sr, Mo and W all preferentially partition into carbonatite melt and have fluid-melt distribution coefficients (D f/m) below unity. The REE partitioning is slightly dependent on the major element (Ca, Mg and Na) composition of the starting mixtures, and it is influenced by temperature, pressure, and the presence of halogens. The fluid-melt D values of individual REE vary from 0.02 to 0.15 with Df/mLu being larger than Df/mLa by a factor of 1.1-2. The halogens F and Cl have strong and opposite effects on the REE partitioning. Fluid-melt D REE are about three times higher in F-bearing compositions and ten times lower in Cl-bearing compositions than in halogen-free systems. Df/mW and Df/mMo are the highest among the studied elements and vary between 0.6 and 0.7; Df/mBa is between 0.05 and 0.09, whereas Df/mSr is at about 0.01-0.02. The results imply that carbonatite-related REE deposits were probably formed by fractional crystallization of carbonatitic melts rather than from exsolved hydrothermal fluids. The same appears to be true for a carbonatite-related Mo deposit recently discovered in China.
DS1997-0284
1997
Veksler, I.Dorfman, A., Veksler, I., Dingwell, D.Study of element distribution between immiscible silicate and carbonate liquid using a centrifuge auto..Geological Association of Canada (GAC) Abstracts, POSTER.GlobalBlank
DS201112-1085
2011
Veksler, I.Veksler, I.Natrocarbonatite-nephelinite liquid immiscibility and element partitioning in comparison with other types of salt silicate unmixing.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractCarbonatite
DS1990-1509
1990
Veksler, I.V.Veksler, I.V., Teptelev, M.Conditions for crystallization and concentration of perovskite-type minerals in alkaline magmasLithos, Special Issue, Vol. 25, No. 4, pp. 177-189RussiaAlkaline rocks, Perovskite
DS1991-1789
1991
Veksler, I.V.Veksler, I.V., Teptelev, M.P.Phase equilibration temperatures in the nepheline diopside sphene systemDoklady Academy of Science USSR, Earth Science Section, Vol. 309, No. 1-6, July pp. 219-222RussiaExperimental petrology, Nepehone
DS1993-1045
1993
Veksler, I.V.Mineyev, S.D., Bogdanovsky, O.G., Veksler, I.V., Karpenko, S.F.Isotopic classification of mantle magmas: effects from low degrees ofmelting.Geochemistry International, Vol. 30, No. 7, pp. 24-33.MantleBasaltic magmas, Geochronology
DS1994-1848
1994
Veksler, I.V.Veksler, I.V.Effect of phlogopite crystallization on the evolution of ultramafic alkaline magmas.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. PosterRussiaAlkaline rocks, Magma
DS1995-1983
1995
Veksler, I.V.Veksler, I.V., Sokolov, S.V.Evolution of carbonatite melts in ultramafic alkaline intrusions: evidence from melt inclusions study.Eos, Abstracts, Vol. 76, No. 17, Apr 25, p. S 270.TanzaniaCarbonatite, natroCarbonatite, Deposit -Oldoinyo-Lengai
DS1997-0845
1997
Veksler, I.V.Nielsen, T.F.D., Solovova, I.P., Veksler, I.V.Parental melts of melilitolite and origin of alkaline carbonatite: evidence from crystallized melt inclusionsContributions to Mineralogy and Petrology, Vol. 126, No. 4, pp. 331-344.GreenlandGardiner Complex, Melilitolite
DS1997-0846
1997
Veksler, I.V.Nielson, T.F.D., Veksler, I.V.Ultramafic alkaline complexes; lines of liquid descent and origin of natrocarbonatite in the Gardner ComplexGeological Association of Canada (GAC) Abstracts, GreenlandAlkaline rocks, Deposit - Gardiner Complex
DS1997-1080
1997
Veksler, I.V.Sokolov, S.V., Veksler, I.V.Mineralogy of melt inclusions in niocalite from carbonatites of the OkaComplex, Canada.Geological Association of Canada (GAC) Abstracts, POSTER.QuebecCarbonatite
DS1998-1533
1998
Veksler, I.V.Veksler, I.V., Nielsen, T., Sokolov, S.Mineralogy of crystallized melt inclusions from Gardiner and Kovdorul tramafic alkaline complexes...Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2015-31.Greenland, Russia, Kola PeninsulaCarbonatite, genesis, Deposit - Gardiner, Kovdor
DS1998-1534
1998
Veksler, I.V.Veksler, I.V., Petibon, Jenner, Dorfman, DingwellTrace element partitioning in immiscible silicate carbonate liquid systems:an initial experimenatal ...Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2095-2104.MantleCarbonatite, Petrology - experimental
DS2001-0836
2001
Veksler, I.V.Nielsen, T.F.D., Veksler, I.V.Oldoinyo Lengai natrocarbonatite revisited: a cognate fluid condensate?Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 27. (abs)TanzaniaCarbonatite, Oldoinyo Lengai
DS2002-1136
2002
Veksler, I.V.Nielsen, T.F., Veksler, I.V.Is natrocarbonatite a cognate fluid condensate?Contributions to Mineralogy and Petrology, Vol. 142, No. 4, pp. 425-35.BlankPetrology - genesis
DS200712-1116
2007
Veksler, I.V.Veksler, I.V., Lentz, D.Parental magmas of plutonic carbonatites, carbonate silicate immiscibility and decarbonation reactions: evidence from melt and fluid inclusions.Mineralogical Association of Canada, Vol. 36, pp. 123-150.MantleCarbonatite
DS201312-0674
2013
Veksler, I.V.Osovetskii, B.M., Reguir, E.P., Chakhmouradian, A.R., Veksler, I.V., Yang, P., Kamanetsky, V.S., Camacho, A.Trace element analysis and U-Pb geochronology of perovskite and its importance for tracking unexposed rare metal and diamond deposits.GAC-MAC 2013 SS4: Diamond: from birth to the mantle emplacement in kimberlite., abstract onlyMantleGeochronology
DS201901-0016
2019
Veksler, I.V.Chebotarev, D.A., Veksler, I.V., Wohlgemuth-Uberwasser, C., Doroshkevich, A.G., Koch-Muller, M.Experimental study of trace element distribution between calcite, fluorite and carbonatitic melt in the systemCaCO3+CaF2+Na2CO3+-Ca3(P04)2 at 100MPa.Contributions to Mineralogy and Petrology, Vol. 174, 4, doi.org/10. 1007/s00410-018-1530-x 13p.Mantlecarbonatite

Abstract: Here we present an experimental study of the distribution of a broad range of trace elements between carbonatite melt, calcite and fluorite. The experiments were performed in the CaCO3 + CaF2 + Na2CO3 ± Ca3(PO4)2 synthetic system at 650-900 °C and 100 MPa using rapid-quench cold-seal pressure vessels. Starting mixtures were composed of reagent-grade oxides, carbonates, Ca3(PO4)2 and CaF2 doped with 1 wt% REE-HFSE mixture. The results show that the distribution coefficients of all the analyzed trace elements for calcite and fluorite are below 1, with the highest values observed for Sr (0.48-0.8 for calcite and 0.14-0.3 for fluorite) and Y (0.18-0.3). The partition coefficients of REE gradually increase with increasing atomic number from La to Lu. The solubility of Zr, Hf, Nb and Ta in the synthetic F-rich carbonatitic melts, which were used in our experiments, is low and limited by crystallization of baddeleyite and Nb-bearing perovskite.
DS201112-1086
2011
Veksler, I.Y.Veksler, I.Y.Natrocarbonatite nephelinite liquid immiscibility and element partitioning in comparison with other types of salt-silicate unmixing.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.156-157.Africa, TanzaniaOldoinyo Lengai
DS201112-1087
2011
Veksler, I.Y.Veksler, I.Y.Natrocarbonatite nephelinite liquid immiscibility and element partitioning in comparison with other types of salt-silicate unmixing.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.156-157.Africa, TanzaniaOldoinyo Lengai
DS1995-1024
1995
Vekster, I.V.Krigman, L.D., Kogarko, L.N., Vekster, I.V.Melilite melt equilibrium and the role of melilite in the evolution of ultralkaline magmas.Geochemistry International, Vol. 32, No. 8, Aug. 1, pp. 91-101.GlobalMelilites
DS1860-0347
1880
Velain, CH.Velain, CH.Title Unknown... Paper Reported on the Mineralogy of Specimens Presented to Velain Professor of Mineralogy at the Sorbonne. the Specimens Were from China.Bulletin Societe Geologique France., China, ShandongDiamond Occurrence
DS201112-0379
2011
Velaquez, V.F.Gomes, C.B., Velaquez, V.F., Azzone, R.G., Paula, G.S.Alkaline magmatism in the Amambay area, NE Paraguay: the Cerro Sarambi complex.Journal of South American Earth Sciences, Vol. 32, 1, pp. 75-95.South America, ParaguayMagmatism - not specific to diamonds
DS1993-0664
1993
Velarde, J.A.Heuschmidt, B., Miranda, R.M., Velarde, J.A.Summary of geological history of Bolivia - precambrian shield, Cordillera Paleozoic belt, Altiplano and western Cordiller volcanic belt, northernpiedmontBolinwest/Carana publication, 135p. approx. $ 20.00BoliviaGeology, Regional overviews
DS1994-1978
1994
Velasco, A.A.Zandt, G., Velasco, A.A., Beck, S.L.Composition and thickness of the southern Altiplano crust, BoliviaGeology, Vol. 221, No. 11, November pp. 1003-1006BoliviaTectonics, Cordilleran -Andes
DS200712-0361
2007
Velasco, A.A.Gilbert, H., Velasco, A.A., Zandt, G.Preservation of Proterozoic terrane boundaries within the Colorado Plateau and implications for its tectonic evolution.Earth and Planetary Science Letters, Vol. 256, 1-2, June 15, pp. 237-248.United States, Colorado PlateauTectonics
DS2003-1118
2003
Velasquez, C.R.Pulfrich, A., Parkins, C.A., Branch, G.M., Bustamante, R.H., Velasquez, C.R.The effects of sediment deposits from Namibian diamond mines on intertidal andAquatic Conservation, Vol. 13, 3, pp. 257-78. Ingenta 1032281872NamibiaEnvironment
DS200412-1600
2003
Velasquez, C.R.Pulfrich, A., Parkins, C.A., Branch, G.M., Bustamante, R.H., Velasquez, C.R.The effects of sediment deposits from Namibian diamond mines on intertidal and subtidal reefs and rock lobster populations.Aquatic Conservation, Vol. 13, 3, pp. 257-78. Ingenta 1032281872Africa, NamibiaEnvironment
DS1997-0204
1997
Velazquez, V.F.Comin- Chiaramonti, P., Cundari, A., Velazquez, V.F.Potassic and sodic igneous rocks from eastern Paraguay: their origin From the lithospheric mantle ...genetic..Journal of Petrology, Vol. 38, No. 4, April 1, pp. 495-ParaguayAlkaline rocks, Parana flood tholeiites
DS2000-0629
2000
Velazquez, V.F.Matos, J.B., Gomes, C.B., Ruberti, Velazquez, V.F.Petrography and geochemistry of alkaline plugs from Sao Pedro, POr to Conceicao Morro Distante.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Mato GrossoAlkaline rocks, Paraguay Province
DS2002-1279
2002
Velcourt, G.Power, M., Velcourt, G.Developments in ground geophysical tecniques for kimberlite exploration30th. Yellowknife Geoscience Forum, Abstracts Of Talks And Posters, Nov. 20-22, p. 50,51. abstractNorthwest TerritoriesGeophysics - techniques
DS1990-1510
1990
Velde, B.Velde, B., Dubois, J., Touchard, G., Badri, A.Fractal analysis of fractures in rocks: the Cantor's dust methodTectonophysics, Vol. 179, pp. 345-352GlobalFractal analysis, Methodology
DS1991-1790
1991
Velde, B.Velde, B., Dubois, J., Moore, D., Touchard, G.Fractal patterns of fractures in granitesEarth Planetary Science Letters, Vol. 104, No. 1, May pp. 25-35GlobalGranites, Fractals
DS1975-0203
1975
Velde, D.Velde, D.Armacolite- Ti Phlogopite-diopside-analcite Lamproites From smokey Butte, Garfield County, Montana.American Mineralogist., Vol. 60, PP. 566-573.MontanaKimberlite, Rocky Mountains
DS1975-0645
1977
Velde, D.Velde, D., Yoder, H.S.JR.Melilite and Melilite Bearing Igneous RocksCarnegie Institute Yearbook, FOR 1976, PP. 478-485.Hawaii, Canary IslandsRelated Rocks'mineralogy
DS1985-0706
1985
Velde, D.Wagner, C., Velde, D.Mineralogy of two peralkaline, afrvedsonite bearing minettes; a new occurrence on zn rich chromiteBulletin. de Mineralogie, Vol. 108, No. 2, pp. 173-187GlobalMinette
DS1985-0707
1985
Velde, D.Wagner, C., Velde, D.Mineralogy of 2 Peralkaline, Arfvedsonite-bearing Minettes-a New Occurrence of Zn Rich Chromite.Bulletin. MINERALOGIQUE., Vol. 108, No. 2, PP. 173-187.GlobalMinette
DS1986-0850
1986
Velde, D.Wagner, C., Velde, D.The mineralogy of K richterite bearing lamproites. A reviewAmerican Mineralogist, Vol. 71, No. 1-2, Jan-Feb. pp. 17-37GlobalAustralia, Lamproite
DS1986-0851
1986
Velde, D.Wagner, C., Velde, D.Lamproites in north Vietnam- a re-examination of coecites(technicalnote)Journal of Geology, Vol. 94, No. 5, September pp. 770-776GlobalLamproite
DS1986-0852
1986
Velde, D.Wagner, C., Velde, D.Davanite K2TiSi6O15 in the Smoky Butte lamproitesAmerican Mineralogist, Vol. 71, pp. 1473-1475MontanaLamproites, Mineralogy
DS1987-0486
1987
Velde, D.Mokhtari, A., Velde, D.Sector zoned kaesutite in camptonites from MoroccoMineralogical Magazine, Vol. 51, No. 359, pp. 151-156MoroccoMineralogy
DS1987-0773
1987
Velde, D.Wagner, C., Velde, D.Aluminous spinels in lamproites: occurrence and probable significanceAmerican Mineralogist, Vol. 72, No. 7-8, pp. 689-696GlobalLamproite, Mica
DS1987-0774
1987
Velde, D.Wagner, C., Velde, D., Mokhtari, A.Sector zones phlogopites in igneous rocksContributions to Mineralogy and Petrology, Vol. 96, pp. 186-191UtahShonkinite, Melilitite
DS1987-0775
1987
Velde, D.Wagner, C., Velde, D., Mokhtari, A.Sector zoned phlogopites in igneous rocksContributions to Mineralogy and Petrology, Vol. 96, No.2, pp. 186-191UtahSmith Morehouse Canyon, Melilitite
DS1988-0482
1988
Velde, D.Mokhtari, A., Velde, D.Xenocrysts in eocene camptonites from Taourirt, Northern MoroccoMineralogical Magazine, Vol. 52, No. 368, December pp. 587-601MoroccoCamptonite
DS1988-0712
1988
Velde, D.Turpin, L., Velde, D., Pinte, G.Geochemical comparison between minettes and kersantites from the Western European Hercynian orogen-trace element and lead Sr neodymium isotope constraints on their originEarth and Planetary Science Letters, Vol. 87, No. 1-2, January pp. 73-86EuropeMinette
DS1989-1548
1989
Velde, D.Velde, D., Medenbach, O., Wagner, C., Schreyer, W.Chayesite, K(Mg,Fe2+)4 Fe3+[Si12)30American Mineralogist, Vol. 74, No. 11, 12 November-December, pp. 1368-1373UtahLamproite, chaysite, osumilite group, Chayesite -Moon Canyon, magnesium silicate
DS1993-1686
1993
Velde, D.Wagner, C., Mokhtari, A., Velde, D.Xenocrystic richterite in an olivine nephelinite -destabilization and diffusion phenomena.Mineralogical Magazine, Vol. 57, No. 388, September pp. 515-525.GlobalMineralogy, Nephelinite
DS1993-1687
1993
Velde, D.Wagner, C., Velde, D.Paleozoic olivine-bearing lamprophyre from the Couy (Cher, France)borehole. Mineral composition and alteration phenomena.European Journal of Mineralogy, Vol. 5, pp. 85-96.FranceLamprophyre, Olivine
DS1996-0986
1996
Velde, D.Mokhtari, A., Wagner, C., Velde, D.Decouverte d'une enclave de carbonatite dans une camptonite de la region deTaourirt, northeast Maroc.C.r. Academy Of Science Paris, Vol. 323, 11a pp. 467-474.MoroccoCarbonatite, Camptonite
DS1997-1152
1997
Velde, D.Thompson, R.N., Velde, D., Leat, P.T., Morrison, MitchellOligocene lamproite containing an Aluminum poor, Titanium rich biotite, Middle Park, northwest Colorado, USAMineralogical Magazine, No. 407, August pp. 557-572.ColoradoLamproite, Deposit - Middle Park area
DS1998-0533
1998
Velde, D.Grey, I.E., Velde, D., Criddle, A.J.Haggertyite, a new magnetoplumbite type titanate mineral from the Prairie Creek (Arkansaw) lamproite.American Mineralogist, Vol. 83, pp. 1323-9.ArkansasLamproite - mineralogy, Deposit - Prairie Creek
DS2000-0978
2000
Velde, D.Velde, D.Mineralogy of mafic xenoliths and their reaction zones in the olivine lamproite from Prairie Creek Arkansaw ..American Mineralogist, Vol. 85, pp. 420-9.ArkansasLamproite, mineralogy, Deposit - Prairie Creek
DS200512-0113
2005
VelemansBrenker, F.E., Vincze, L., Velemans, Nasdala, Stachel, Vollmer, Kersten, Somogyi, Adams, Joswig, HarrisDetection of a Ca rich lithology in the Earth's deep ( >300km) convecting mantle.Earth and Planetary Science Letters, Vol. 236, 3-4, pp. 579-587.Africa, GuineaKankan, diamond inclusions, spectroscopy
DS201012-0816
2010
Velentini, L.Velentini, L., Moore, K.R., Chazot, G.A fluid dynamical model of carbonatite silicate magma interaction.International Mineralogical Association meeting August Budapest, abstract p. 579.Europe, France, globalCarbonatite
DS2002-0459
2002
VelezFinn, C.A., Pilkington, M., Miles, Hernadez, Cuevas, Velez, Sweeney, KucksThe new North American magnetic anomaly mapGeological Society of America Annual Meeting Oct. 27-30, Abstract p. 387.United States, CanadaMap - magnetic
DS201112-0955
2010
Veligzhanin, A.A.Shiryaev, A.A., Zubavichus, Y.V., Veligzhanin, A.A., McCammon, C.Local environment and valence state of iron in Micro inclusions in fibrous diamonds: x-ray absorption and Mossbauer data.Russian Geology and Geophysics, Vol. 51, pp. 1262-1266.Africa, Democratic Republic of Congo, South America, BrazilDiamond morphology
DS1982-0617
1982
Velikii, N.M.Velikii, N.M., Miletskii, B.E.Occurence of Diamonds in the Lower Cretaceous Deposits of The Aktuybinsk Priuralie.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 265, No. 2, PP. 397-399.RussiaBlank
DS1993-1655
1993
Velikin, S.A.Velikin, S.A.Use of borehole geophysics monitoring for brine controlDiamonds of Yakutia, pp. 135-138.Russia, YakutiaKimberlites, Geophysics
DS200612-0189
2006
VelikoslavinskiiBuchko, I.V., Salnikova, E.B., Kotov, A.B., Larin, A.M., Velikoslavinskii, Sorokin, Sorokin, YakovlevaPaleoproterozoic gabbro anorthosites of the Selenga Superterrane, southern framing of the Siberian Craton.Doklady Earth Sciences, Vol. 407, 3, pp. 372-375.Russia, SiberiaTectonics
DS1992-1558
1992
Velikoslavinsky, S.D.Tolmacheva, Ye.., Velikoslavinsky, S.D.On a presumed find of moissanite in the Lower Precambrian rocks of the Aldan Shield.Doklady Academy of Sciences USSR, Earth Science Section, Vol. 314, No. 1-6, July 1992, pp. 97-100.Russia, AldanMoissanite, Mineralogy
DS201712-2686
2017
Velikoslavinsky, S.D.Gladkochub, D.P., Donskaya, T.V., Sklyarov, E.V., Kotov, A.B., Vladykin, N.V., Pisarevsky, S.A., Larin, A.M., Salnikova, E.B., Saveleva, V.B., Sharygin, V.V., Starikova, A.E., Tolmacheva, E.V., Velikoslavinsky, S.D., Mazukabzov, A.M., Bazarova, E.P., KovaThe unique Katugin rare metal deposit ( southern Siberia): constraints on age and genesis.Ore Geology Reviews, in press available, 18p.Russia, Siberiadeposit - Katugin

Abstract: We report new geological, mineralogical, geochemical and geochronological data about the Katugin Ta-Nb-Y-Zr (REE) deposit, which is located in the Kalar Ridge of Eastern Siberia (the southern part of the Siberian Craton). All these data support a magmatic origin of the Katugin rare-metal deposit rather than the previously proposed metasomatic fault-related origin. Our research has proved the genetic relation between ores of the Katugin deposit and granites of the Katugin complex. We have studied granites of the eastern segment of the Eastern Katugin massif, including arfvedsonite, aegirine-arfvedsonite and aegirine granites. These granites belong to the peralkaline type. They are characterized by high alkali content (up to 11.8?wt% Na2O?+?K2O), extremely high iron content (FeO?/(FeO??+?MgO)?=?0.96-1.00), very high content of most incompatible elements - Rb, Y, Zr, Hf, Ta, Nb, Th, U, REEs (except for Eu) and F, and low concentrations of CaO, MgO, P2O5, Ba, and Sr. They demonstrate negative and CHUR-close ?Nd(t) values of 0.0…?1.9. We suggest that basaltic magmas of OIB type (possibly with some the crustal contamination) represent a dominant part of the granitic source. Moreover, the fluorine-enriched fluid phases could provide an additional source of the fluorine. We conclude that most of the mineralization of the Katugin ore deposit occurred during the magmatic stage of the alkaline granitic source melt. The results of detailed mineralogical studies suggest three major types of ores in the Katugin deposit: Zr mineralization, Ta-Nb-REE mineralization and aluminum fluoride mineralization. Most of the ore minerals crystallized from the silicate melt during the magmatic stage. The accessory cryolites in granites crystallized from the magmatic silicate melt enriched in fluorine. However, cryolites in large veins and lens-like bodies crystallized in the latest stage from the fluorine enriched melt. The zircons from the ores in the aegirine-arfvedsonite granite have been dated at 2055?±?7?Ma. This age is close to the previously published 2066?±?6?Ma zircon age of the aegirine-arfvedsonite granites, suggesting that the formation of the Katugin rare-metal deposit is genetically related to the formation of peralkaline granites. We conclude that Katugin rare-metal granites are anorogenic. They can be related to a Paleoproterozoic (?2.05?Ga) mantle plume. As there is no evidence of the 2.05?Ga mantle plume in other areas of southern Siberia, we suggest that the Katugin mineralization occurred on the distant allochtonous terrane, which has been accreted to Siberian Craton later.
DS200612-1477
2006
Velimsky, J.Velimsky, J., Martinec, Z., Everett, M.E.Electrical conductivity in the Earth's mantle inferred from CHAMP satellite measurements 1. Dat a processing and 1-D inversion.Geophysical Journal International, Vol. 166, 2, pp. 529-542.MantleGeophysics
DS2002-1659
2002
Velinsky, V.V.Velinsky, V.V., Pavlov, A.L.Rocks of the boninite series: products of interaction between calc alkaline magmas and serpentinites.Doklady Earth Sciences, Vol. 387A,9, pp. 1092-94.MantleMagmatism, Boninites
DS2002-1660
2002
Velinsky, V.V.Velinsky, V.V., Pavlov, A.L.Rocks of the boninite series: products of interaction between calc alkaline magmas and serpentinites.Doklady, Vol. 387A, Nov-Dec. No. 9, pp. 1092-5.RussiaBoninites
DS200412-0078
2004
Velivetskaya, T.A.Avchenko, O.V., Lavrik, S.N., Aleksandrov, I.A., Velivetskaya, T.A.Isotopic heterogeneity of carbon in metamorphic fluid.Doklady Earth Sciences, Vol. 394, 1, pp. 81-84.Russia, Aldan ShieldMetamorphism, petrology
DS200712-0375
2007
Velivetskaya, T.A.Gornova, M.A., Polozov, A.G., Ignatev, A.V., Velivetskaya, T.A.Peridotite nodules from the Udachnaya kimberlite pipe, nonmantle oxygen isotope ratios in garnets.Doklady Earth Sciences, Vol. 415, 5, pp. 777-781.RussiaDeposit - Udachnaya
DS201212-0376
2012
Velivetskaya, T.A.Kostrovitskii, S.I., Soloveva, L.V., Gornova, M.A., Alymova, N.V., Yakolev, D.A., Ignative, A.V., Velivetskaya, T.A., Suvorova, L.F.Oxygen isotope composition in minerals of mantle parageneses from Yakutian kimberlites.Doklady Earth Sciences, Vol. 444, 1, pp. 579-584.Russia, YakutiaDeposit - Udachnaya, Komsomolskaya
DS1990-1470
1990
Velkoslavinskii, S.D.Tolmacheva, Y.V., Velkoslavinskii, S.D.On the supposed moissonite finding in early Precambrian formations of the Aldanian shield.(Russian)Doklady Academy of Sciences Nauk. SSSR, (Russian), Vol. 314, No. 5, pp. 1215-1217RussiaMineralogy, Moissonite
DS1990-1059
1990
Veltman, C.B.Mogessie, A., Tessadri, R., Veltman, C.B.electromagnetic-AMPH - a hypercard program to determine the name of an amphibole from electron microprobe analysis accordto the international mineralogical association schemeComputers and Geosciences, Vol. 16, No. 3, pp. 309-330GlobalComputer, Program -EMP-AMPH
DS2001-1199
2001
Ven der Lee, S.Ven der Lee, S., James, D., Silver, P.Upper mantle S velocity structure of central and south AmericaJournal of Geophysical Research, Vol. 106, No. 12, pp. 30,821-34.South AmericaTectonics, Geophysics
DS201112-1036
2011
Ven der Meer, F.D.Tedia, G.E., Van der Meijde, M., Nyblade, A.A., Ven der Meer, F.D.A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution.Geophysical Journal International, Vol. 187, 1, pp. 1-9.AfricaGeophysics - gravity
DS1999-0769
1999
Ven Keken, A.Ven Keken, A.Mixing in a 3D spherical model of present day mantle convectionEarth and Planetary Science Letters, Vol. 171, No. 4, Sept. 30, pp. 533-48.MantleConvection
DS2003-0918
2003
Venance, K.McMartin, I., Henderson, P.J., Kjarsgaard, B.K., Venance, K.Regional distribution and chemistry of kimberlite indicator minerals, Rankin In let andGeological Survey of Canada Open File, No. 1575, 1 CD Rom 110p. report 60p. of appendices $40.NunavutMineral chemistry
DS202203-0343
2022
Venance, K.E.Desbarats, A.J., Percival, J.B., Bilot, I., Polivchuk, M.J., Venance, K.E.Drainage geochemistry of mine tailings from a carbonatite-hosted Nb-REE deposit, Oka Quebec, Canada.Applied Geochemistry, Vol. 138, 14p. PdfCanada, Quebecdeposit - Oka

Abstract: Potential environmental issues associated with the mining of carbonatites are receiving increased attention due to the importance of critical metals for green technologies. This study investigates the chemistry of tailings seepage at the former Saint Lawrence Columbium mine near Oka, Québec, Canada, which produced pyrochlore concentrate and ferroniobium from a carbonatite-hosted Nb-REE deposit. Detailed field sampling and laboratory methods were used to characterize the hydraulic properties of the tailings, their bulk chemistry, mineralogy, pore water and effluent chemistries. The tailings are composed of REE-enriched calcite (64-89 wt %) and fluorapatite (2-22 wt %), as well as biotite (6-17 wt %) and chlorite (0-7 wt %). Minor minerals include ankerite, pyrite, sphalerite, molybdenite, magnetite and unrecovered pyrochlore. Secondary minerals include gypsum, barite, strontianite and rhodochrosite. Geochemical mass balance modeling, constrained by speciation modeling, was used to identify dissolution, precipitation and exchange reactions controlling the chemical evolution of pore water along its flow path through the tailings impoundment. In the unsaturated zone, these reactions include sulfide oxidation and calcite dissolution with acid neutralization. Below the water table, gypsum dissolution is followed by sulfate reduction and FeS precipitation driven by the oxidation of organic carbon in the tailings. Incongruent dissolution of biotite and chlorite releases K, Mg, Fe, Mn, Ba and F and forms kaolinite and Ca-smectite. Cation exchange reactions further remove Ca from solution, increasing concentrations of Na and K. Fluoride concentrations reach 23 mg/L and 8 mg/L in tailings pore water and effluent, respectively. These values exceed Canadian guidelines for the protection of aquatic life. In the mildly alkaline (pH 8.3) pore waters, Mo is highly mobile and reaches an average concentration of 83 ?g/L in tailings effluent, which slightly exceeds environmental guidelines. Concentrations (unfiltered) of Zn reach 1702 ?g/L in tailings pore water although values in effluent are usually less than 20 ?g/L. At the ambient pH, Zn is strongly adsorbed by Fe-Mn oxyhydroxides. Although U forms mobile complexes in tailings pore water, concentrations do not exceed 16 ?g/L due to the low solubility of its pyrochlore host. Adsorption and the low solubility of pyrochlore limit concentrations of Nb to less than 49 ?g/L. Cerium, from calcite dissolution, is strongly adsorbed although it reaches concentrations (unfiltered) in excess of 1 mg/L and 100 ?g/L in pore water and effluent, respectively. Results of this study show that mine tailings from carbonatite deposits are enriched in a wide variety of incompatible elements with multiple mineral hosts of varying solubility. Some of these elements, such as F and Mo, may represent contaminants of concern because of their mobility in alkaline tailings waters.
DS1991-1791
1991
Vendeville, B.Vendeville, B.Mechanisms generating normal fault curvature: a review illustrated by physical modelsThe geometry of normal faults, editors Roberts, A.M., Yielding, G., No. 56, pp. 241-249GlobalStructure -faults, Fault geometry -models
DS1994-0815
1994
Vendeville, B.C.Jackson, M.P.A., Vendeville, B.C.Regional extension as a geologic trigger for diapirisMGeological Society of America Bulletin, Vol. 106, No. 1, January pp. 57-73GlobalTectonics, Salt diapirs
DS1986-0610
1986
Vendrell-Saz, M.Nogues-Carulla, J.M., Vendrell-Saz, M., Arbunies, M., Lopez-SolerPhotometric study of UV-luminescence of cut diamonds,and its relationship with their colour classificationFourteenth General Meeting of IMA., p. 187. (abstract.)GlobalDiamond morphology, UV-luminescence
DS1980-0338
1980
Vendrell-Saz, N.Vendrell-Saz, N., et al.Transmission et Absorption des Diamants Tailles de la Serie"cape".Rev. Gemmol. A.f.g., No. 64, PP. 20-24.South AfricaDiamond
DS200912-0793
2009
Venet, L.Venet, L., Duffar, T., Deguen, R.Grain structure of the Earth's inner core.Comptes Rendus Geoscience, In press available, 4p.MantleGeophysics - seismics
DS200412-2052
2003
Venezuela Energy and Mines MinistryVenezuela Energy and Mines MinistryVenezuela defends ending De Beers technical accord.Reuters, Oct. 22, 1p.South America, VenezuelaNews item - De Beers, legal
DS1994-1849
1994
Venezuela Mining IndustryVenezuela Mining IndustryDiamonds... brief overviewVenezuela Mining Industry, pp. 26-27.VenezuelaNews item, Economics
DS201312-0521
2013
Venkat Raju, D.Ch.Kumar, M.R., Mishra, D.C., Singh, B., Venkat Raju, D.Ch., Singh, M.Geodynamics of NW India: subduction, lithospheric flexure , ridges and seismicity.Journal Geological Society of India, Vol. 81, pp. 61-78.IndiaGravity - bouguer
DS200612-0244
2005
Venkata Dasu, S.P.Chelani, S.K., Shrivastava, S.K., Venkata Dasu, S.P., Thiruvengadam, A., Keshavamurthy, K.N., Bhaisal, R.An integrated approach for searching KCR bodies in the eastern part of the Bastar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 98-99.India, Bastar CratonDiamond exploration
DS1988-0729
1988
Venkatakrishnan, R.Venkatakrishnan, R., Culver, S.J.Plate boundaries in west Africa and their implications for Pangean continental fitGeology, Vol. 16, No. 4, April pp. 322-325West AfricaBlank
DS1989-1549
1989
Venkatakrishnan, R.Venkatakrishnan, R., Culver, S.J.Tectonic fabric of Sierra Leone, West Africa-implications for Mesozoic continental breakupJournal of the Geological Society of London, Vol. 146, November pp. 991-1002Sierra LeoneTectonics, Rifting
DS1985-0474
1985
Venkatanarayana, B.Nagabhushanam, B., Venkatanarayana, B.Geology and Geochemistry of Kimberlites of Wajrakarur Area, anantapur District, Andhra Pradesh.Geophysical Research. Bulletin., Vol. 23, No. 1, PP. 43-54.India, Andhra Pradesh, WajrahkarurPetrology, Mineral Chemistry, Geochronology
DS200512-1136
2004
Venkataraman, A.Venkataraman, A., Nyblade, A.A., Ritsema, J.Upper mantle Q and thermal structure beneath Tanzania, East Africa from teleseismic P wave spectra.Geophysical Research Letters, Vol. 31, 15, L15611 DOI 10.1029/2004 GL020351Africa, TanzaniaGeothermometry
DS1960-0105
1960
Venkataraman, K.Venkataraman, K.Petrology of the Majhgawan Agglomeratic Tuff and Associatedrocks.Quarterly Journal of Geology MIN. MET. SOC. INDIA., Vol. 32, PP. 1-10.IndiaRelated Rocks, Petrology
DS1975-0479
1977
Venkataraman, K.Chattopadhyay, P.B., Venkataraman, K.Petrography and Petrochemistry of the Kimberlite and Associated Volcanic Rocks of the Jungel Valley, Mirzapur District, uttar Pradesh.Geological Society INDIA Journal, Vol. 18, No. 12, DECEMBER PP. 653-661.India, Uttar PradeshPetrography
DS1988-0037
1988
Venkatasubramanian, P.Bandopadhyay, S., Venkatasubramanian, P.A rule based expert system for mining method selectionThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 81, No. 919, November pp. 84-88GlobalComputer, Program- expert system
DS200612-0396
2006
Venkatesan, M.Fitzgerald, C.B., Venkatesan, M., Douvalis, A.P., Coey, J.M.Magnetic properties of carbonado diamonds.Journal of Magnetism and Magnetic Materials, Elsevier, Vol. 300, 2, pp. 368-372.TechnologyDiamond morphology
DS2000-0801
2000
Venkatesan, T.R.Ray, J.S., Pande, K., Venkatesan, T.R.Emplacement of Amba Dongar carbonatite alkaline complex at Cretaceous Tertiary boundary: evidence 40Ar 39 ArProceedings Indian Academy of Science, Vol. 109, No. 1, March pp. 39-47.IndiaCarbonatite, Geochronology
DS201312-0940
2012
Venkateschwarlu, M.Venkateschwarlu, M., Chalapathi Rao, N.V.New paleomagnetic and rock magnetic results on Mesoproterozoic kimberlites from the Eastern Dharwar craton, southern India: towards constraining India's position in Rodinia.Precambrian Research, Vol. 224, pp. 588-596.IndiaDeposit - Wjrakarur, Narayanpet, Raichur
DS2002-1380
2002
Venkatesh, A.S.Saha, I., Venkatesh, A.S.Invisible gold within sulphides from the Archean Hutti Maski schist belt, southern IndiaJournal of Asian Earth Sciences, Vol.20,5,pp. 449-57.IndiaGold, copper, Mesothermal, Deposit - Hutti Maski
DS201603-0390
2016
Venkatesh, A.S.Kanouo, N.S., Ekomane, E., Yongue, R.F., Njonfang, E., Zaw, K., Changian, M., Ghogomu, T.R., Lentz, D.R., Venkatesh, A.S.Trace elements in corundum, chrysoberyl, and zircon: application to mineral exploration and provenance study of the western Mamfe gem clastic deposits ( SW Cameroon, Central Africa).Journal of African Earth Sciences, Vol. 113, pp. 35-50.Africa, CameroonGeochemistry

Abstract: Trace element abundances in three indicator minerals (corundum, chrysoberyl, and zircon grains) from the western Mamfe gem placers, as determined by LA-ICP-MS analytical techniques, are shown to be sensitive to their crystallization conditions and source rock types. Corundum is dominantly composed of Al (standardized at 529,300 ppm), Fe (2496-12,899 ppm), and Ti (46-7070 ppm). Among element ratios, Fe/Mg (73-1107), Fe/Ti (0.5-245.0), Ti/Mg (1-175), and Ga/Mg (4-90) are generally higher whereas, Cr/Ga (<0.072) is low. The Fe (?12,899), Ga (?398), Mg (2-62), Cr (1.1-33.0), and V (3.0-93.0) contents (in ppm) mostly typify corundum grains formed in magmatic rocks, although some are metamorphic affiliated. A very higher Ti and significantly low Ga, Ta and Nb contents in some blue grains, suggest interesting concentrations of those high-tech metals in their source rocks. Chrysoberyl is dominantly composed of Al (standardized at 425,000 ppm) and Be (62701-64371 ppm). Iron (7605-9225 ppm), Sn (502-3394 ppm), and Ti (33-2251 ppm) contents are high, whereas Ga (333-608 ppm), Ta (<456.0 ppm), and Nb (<3.0 ppm) are significantly low. The high (Be and Sn) and significantly low Ga-Rb abundances, and Ta > Nb in the western Mamfe chrysoberyls show that they were crystallized in granitic pegmatites, with some of those source rocks being enriched in Ta and Sn. Zirconium oxide (ZrO2: standardized at 66.1 wt.%)) is the only major oxide in analysed coarse-grained zircons. Within the minor elementary suites: Hf (4576-12,565 ppm) and Y (48-2805 ppm) contents are significantly high. The trace element suites include: Th (7-1565 ppm), U (13-687 ppm), and ?REE (50-2161 ppm), whose values are significantly low. The (Yb/Sm)N, Ce/Ce*, and Eu/Eu* anomalies range from 1.0 to 227.0, 0 to 308, and 0.08 to 1.7 respectively. They are Hf-Y-HREE enriched and depleted zircons mainly crystallized in magmatic oxidized environments. They were mainly sorted from granitoids, syenites and kimberlites.
DS200412-1843
2004
Venkatesh, N.S.Singh, U.P., Venkatesh, N.S., Godhavari, K.S., et al.Lamprophyre dykes in Chotanagpur gneissic complex, near Simdega Gumla District Jkarkhand.Journal of the Geological Society of India, Vol. 63, 6, pp. 655-658.IndiaLamprophyre, drainage basin
DS201012-0817
2010
Venkateshwariu, M.Venkateshwariu, M.Paleomagnetic study of kimberlite dykes from eastern Dharwar Craton, India.International Dyke Conference Held Feb. 6, India, 1p. AbstractIndiaDeposit - Mahaboobnagar clan
DS201212-0754
2013
Venkateshwarlu, M.Venkateshwarlu, M., Chalapathi Rao, N.V.New paleomagnetic and rock magnetic results on Mesoproterozoic kimberlites from the Eastern Dharwar craton, southern India: towards constraining India's position in Rodinia.Precambrian Research, Vol. 224, pp. 588-596.IndiaDeposit - Wajrakrur, Narayanpet, Raichur
DS1940-0135
1946
Venkayya, P.Venkayya, P.World's Unknown Parent Rock of DiamondKrishi Magazine (bezwada Vijayawada), SPECIAL No. JANUARYIndiaGenesis, Kimberlite
DS201911-2571
2019
Vennari, C.E.Vennari, C.E., Williams, Q.High pressure Raman and Nd3+ luminescence spectroscopy of bastnasite -(REE) CO3f.American Mineralogist, Vol. 104, pp. 1389-1401.Mantleluminescence

Abstract: Bastnäsite-(Ce), a rare earth element (REE) bearing carbonate (Ce,La,Y,Nd,Pr)CO3F, is one of the most common REE-bearing minerals and has importance from both economic and geologic perspectives due to its large REE concentration. It also provides an example of the structural interplay between carbonate groups and fluorine ions, as well as the complex bonding properties of rare earth elements. We report Raman vibrational and Nd3+ luminescence (4F3/2?4I9/2, 4F3/2?4I11/2, and 4F5/2+2H9/2?4I9/2) spectra of natural bastnäsite-(Ce) to 50 GPa at 300 K. Two phase transitions are observed under compression. Bastnäsite-I remains the stable phase up to 25 GPa, where it undergoes a subtle phase transition to bastnäsite-II. This is likely produced by a change in symmetry of the carbonate ion. Bastnäsite-II transforms to bastnäsite-III at ~38 GPa, as demonstrated by changes in the luminescence spectra. This second transition is particularly evident within the 4F3/2?4I9/2 luminescent transitions, and it appears that a new rare earth element site is generated at this phase change. This transition is also accompanied by modest changes in both the Raman spectra and two sets of luminescent transitions. Despite these transformations, the carbonate unit remains a stable, threefold-coordinated unit throughout this pressure range, with a possible increase in its distortion. Correspondingly, the rare-earth element site(s) appears to persist in quasi-ninefold coordination as well, implying that the general bonding configuration in bastnäsite is at least metastable over a ~30% compression range. All pressure-induced transitions are reversible, with some hysteresis, reverting to its ambient pressure phase on decompression.
DS1993-0435
1993
Vennemann, T.Feldstein, S.N., Lange, R.A., Vennemann, T., O'Neil, J.R.Complete chemical analyses and D/H ratios of phlogopite: the importance Of the Oxy-annite component.American Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 636.GlobalExperimental petrology, Phlogopite
DS1995-1294
1995
Vennemann, T.Moore, G., Vennemann, T., Carmichael, I.S.E.Solubility of water in magmas to 2 kbarGeology, Vol. 23, No. 12, Dec. pp. 1099-1102GlobalPetrology -experimental, Magma -water composition
DS2003-0876
2003
Vennemann, T.Markl, G., Abart, R., Vennemann, T., Sommer, H.Mid-crustal metasomatic reaction veins in a spinel peridotiteJournal of Petrology, Vol. 44, 6, pp. 1097-1120.MantleBlank
DS200412-1226
2003
Vennemann, T.Markl, G., Abart, R., Vennemann, T., Sommer, H.Mid-crustal metasomatic reaction veins in a spinel peridotite.Journal of Petrology, Vol. 44, 6, pp. 1097-1120.MantleMetasomatism
DS200712-0681
2007
Vennemann, T.Marks, M.A.W., Rudnick, R.L., McCammon, C., Vennemann, T., Markl, G.Arrested kinetic Li isotope fractionation at the margin of the Ilimaussaq complex: evidence for open system processes during final cooling peralkaline igneous rocksChemical Geology, Vol. 246, 3-4, pp. 207-230.Europe, GreenlandGeochronology
DS200912-0473
2009
Vennemann, T.Marks, M.A.W., Neukirchen, F., Vennemann, T., Markl, G.Textural, chemical and isotopic effects of late magmatic carbonatitic fluids in the carbonatite syenite Tamazeght complex, High Atlas Mountains, Morocco.Mineralogy and Petrology, Vol. 97, pp. 23-42.Africa, MoroccoCarbonatite
DS200912-0776
2009
Vennemann, T.Trumball, R.B., Yang, J-S., Robinson, P.T., Di Pierro, S., Vennemann, T., Wiedenbeck, M.The carbon isotope composition of natural SiC (moissanite) from the Earth's mantle: new discoveries from ophiolites.Lithos, In press - available 31p.MantleMoissanite
DS201312-1004
2013
Vennemann, T.Zaitsev, A.N., Wenzel, T., Vennemann, T., Markl, G.Tinderet volcano, Kenya: an altered natrocarbonatite locality?Mineralogical Magazine, Vol. 77, 3, pp. 213-226.Africa, KenyaCarbonatite
DS202006-0926
2020
Vennemann, T.Keulen, N., Thomsen, T.B., Schumacher, J.C., Poulsen, M.D., Kalvig, P., Vennemann, T., Salimi, R.Formation, origin and geographic typing of corundum ( ruby and pink sapphire) from the Fiskenaesst complex, Greenland.Lithos, Vol. 366-367, 26p. PdfEurope, Greenlandruby

Abstract: Metamorphic petrology observations on rubies found in-situ in their host-rock are combined with geochemical measurements and optical microscopy observations on the same rubies, with the aim of connecting the ruby-forming metamorphic reaction to a unique fingerprint for these minerals. The Fiskenæsset complex in Greenland is used as an area of this case study. Isochemical pressure-temperature sections were calculated based on electron microprobe and whole-rock geochemistry analyses, and compared to field observations. Rubies formed from reaction between olivine/serpentine and anorthite, triggered by the intrusion of a 2.71 Ga pegmatite. Al is sourced from the anorthite reacting to calcic amphibole, silica from the pegmatite reacts with olivine/serpentine to anthophyllite, Cr3+ is mobile in the pegmatitic fluid, giving colour to the rubies. The ruby-forming reaction occurs at about 640 °C and 7 kbar. In order to establish the unique fingerprint for this ruby-bearing ultramafic complex, laser-ablation inductively-coupled-plasma mass-spectrometry trace-element measurements, oxygen isotope compositions, optical microscopy and scanning electron microscopy were applied. Due to the setting in an ultramafic rock-anorthosite-leucogabbro complex, the fingerprint of the rubies from the Fiskenæsset complex is rather unique. Compared to rubies from other localities, Fiskenæsset complex rubies contain high Cr, intermediate Fe, and low V, Ga, and Ti concentrations, low oxygen isotope values (1.6-4.2‰) and a rarely-observed combination of optical growth features and mineral inclusions like anthophyllite+biotite. Results for other Greenland localities are presented and discussed as well. Even though these are derived from ultramafic rock settings too, they record different trace-element ratios and oxygen isotope values, resulting from variations in the Archaean ruby-forming reaction.
DS1998-1535
1998
Vennemann, T.W.Vennemann, T.W.Implications of the revised oxygen isotope and cation exchange thermobarometry for the amphibolite granuliteSouth African Journal of Geology, Vol. 101, No. 2, June pp. 123-142South AfricaLimpopo Belt, southern marginal zone, Geobarometry
DS200412-0438
2004
Vennemann, T.W.Demeny, A., Vennemann, T.W., Ahijado, A., et al.Oxygen isotope thermometry in carbonatites, Fuerteventura Canary Islands, Spain.Mineralogy and Petrology, Vol. 80, 3-4, March pp. 155-172.Europe, Canary IslandsCarbonatite
DS200412-0439
2004
Vennemann, T.W.Demeny, A., Vennemann, T.W., Hegner, E., Nagy, G., Milton, J.A., Embey-Isztin, A., Homonnay, Z., Dobosi, G.Trace element and C O Sr Nd isotope evidence for subduction related carbonate silicate melts in mantle xenoliths ( Pannonian BasLithos, Vol. 75, 1-2, July pp. 89-113.Europe, HungarySubduction, trace element fingerprinting, petrogenetic
DS200612-0114
2006
Vennemann, T.W.Beeskow, B., Treloar, P.J., Rankin, A.H., Vennemann, T.W., Spangenberg, J.A reassessment of models for hydrocarbon generation in the Khibiny nepheline syenite complex, Kola Peninsula, Russia.Lithos, in press availableRussiaAlkalic
DS201112-0924
2011
Vennenmann, T.Schilling, J., Marks, m.A.W., Wenzel, T., Vennenmann, T., Horvth, L., Tarassof, P., Jacob, D.E., Markl, G.The magmatic to hydrothermal evolution of the intrusive Mont Sainte Hilaire Complex: insights into the late stage evolution of peralkaline rocks.Journal of Petrology, Vol. 52, 11. pp. 2147-2185.Canada, QuebecAlkaline rocks, carbonatite
DS200512-0390
2004
Vennnemann, T.Halama, R., Vennnemann, T., Siebel, W., Markl, G.The Gronnedal Ika carbonatite syenite complex, South Greenland: carbonatite formation by liquid immiscibility.Journal of Petrology, Vol. 46, 1-2, pp. 191-217.Europe, GreenlandCarbonatite
DS1986-0703
1986
VenogopalaSarma, S.V.S., Harinarayana, T., Venogopala, Krishna, C., SankerTellurics in the exploration of kimberlite pipes- an experimental studyCurrent Science, Vol. 55, No. 3, pp. 133-136IndiaWajrakarur, LattavaraM., Geophysics
DS201605-0914
2016
Venter, D.Venter, D.Estimation model for ore extraction at Finsch diamond mine.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 263-274.Africa, South AfricaDeposit - Finsch
DS1985-0697
1985
Venterelli, G.Venterelli, G., Balestra, G., Toscani, L.The Ultrapotassic Rocks and their Geologic SettingGeological Association of Canada (GAC)., Vol. 10, P. A65, (abstract.).ItalyLeucite
DS200512-1137
2004
Ventura Santos, R.Ventura Santos, R., Souza de Alvarenga, C.J., Babinski, M., Ramos, M.L.S., Cukrov, N., Fonsec, M.A., Da NorbregaCarbon isotopes of Mesoproterozoic Neoproterozoic sequences from southern Sao Francisco craton and Aracuai Belt, Brazil: paleogeorgraphic implications.Journal of South American Earth Sciences, Vol. 18, 1, Dec. 30, pp. 27-39.South America, BrazilGeomorphology, glaciation, geochronology,carbonatites
DS201012-0144
2010
Ventura Santos, R.De Oliveira Cordeiro, P.F., Brod, J.A., Ventura Santos, R., Dantas, E.L., Gouvieia de Oliveira, C., Soares Rocha, Barbosa, E.Stable ( C,O) and radiogenic (Sr, Nd) isotopes of carbonates as indicators of magmatic and post magmatic processes of phoscorite series rocks and carbonatites fContributions to Mineralogy and Petrology, In press available, 14p.South America, BrazilCatalao I
DS201112-0257
2011
Ventura Santos, R.De Oliveire Cordeiro, P.F., Brod, J.A., Ventura Santos, R., Dantas, E.L., Gouveia de Oliveira, C., Soares Rochas Barbosa, E.Stable (C,O) and radiogenic (Sr,Nd) isotopes of carbonates as indicators of magmatic and post-magmatic processes of phoscorite series rocks and carbonatites from Catalao 1, central Brazil.Contributions to Mineralogy and Petrology, Vol. 161, 3, pp. 451-464.South America, BrazilCarbonatite
DS2001-0251
2001
VenturelleiDi Battistini, G., Montanini, Vernia, VenturelleiPetrology of melilite bearing rocks from Montefiascone volcanic complex: new insights ultrapotassic volcanicsLithos, Vol. 59, No.1-2, Oct. pp. 109-25.ItalyUltrapotassic
DS2001-0253
2001
VenturelliDiBattistini, G., Montanini, Vernia, Venturelli, TonariPetrology of melilite bearing rocks from the Montefiascone volcanic complex Roman magmatic provinceLithos, Vol. 59, No. 1-2, Oct. pp. 1-24.ItalyUltrapotassic volcanism
DS1988-0730
1988
Venturelli, G.Venturelli, G., Mariani, E.S., Foley, S.F., Capedri, S., CrawfordPetrogeneis and conditions of crystallization of SpanishlamproiticrocksCanadian Mineralogist, Vol. 26, No. 1, March pp. 67-80GlobalLamproite
DS1989-0439
1989
Venturelli, G.Foley, S.F., Venturelli, G.High K2O rocks with high MgO, high SiO2 affinitiesIn: Boninites, Editor A.J. Crawford, Unwin and Hyman, pp. 72-88GlobalBoninites, Potassic alkaline rocks
DS1991-1054
1991
Venturelli, G.Mariani, E., Venturelli, G., Toscani, L., Barbieri, M.The Jumilla lamproites, southeast Spain: late magmatic -hydrothermal activityEuropean Current Research Fluid Inclusions, Firenze, Italy April 10-12, Abstracts, ECROFI XI, p. 191-192GlobalLamproite, Jumilla
DS1991-1792
1991
Venturelli, G.Venturelli, G., Capedri, S., Barberi, M., Toscani, L.The Jumilla lamproite revisited - a petrological oddityEur. Journal of Mineralogy, Vol. 3, No. 1, pp. 123-145GlobalLamproite, Petrology -Jumilla
DS1991-1793
1991
Venturelli, G.Venturelli, G., Toscani, L., Salviolini, E., Capedri, S.Mixing between lamproitic and dacitic components in miocene volcanic Rocks of southeast SpainMineralogical Magazine, Vol. 55, No. 379, June pp. 282-285GlobalLamproite, Volcanics
DS1993-0282
1993
Venturelli, G.Contini, S., Venturelli, G., Toscani, L., Capedreini, S.chromium-Zr-armalcolite-bearing lamproites from Cancarix, southeast SpainMineralogical Magazine, Vol. 57, No. 387, June pp. 203-216GlobalLamproites, Mineralogy
DS1993-1656
1993
Venturelli, G.Venturelli, G., Salvioli-Mariani, E., Toscani, L., Barbieri, M., Giorgoni, C.Post-magmatic apatite + hematite + carbonate assemblage in the Jumillalamproites. a fluid inclusion and isotope study.Lithos, Vol. 30, pp. 139-150.GlobalLamproites, Geochronology
DS1996-1249
1996
Venturelli, G.Salvioli-Mariani, E., Venturelli, G.Temperature of crystallization and evolution of the Jumilla and Cancarix lamproites (southeast Spain)....European Journal of Mineralogy, Vol. 8, No.5, Sept. 1, pp. 1027-1040.GlobalLamproite, melting, Deposit - Jumilla, Cancarix
DS1987-0218
1987
Venturello, G.Foley, S.F., Venturello, G., Green, D.H., Toscani, L.The ultrapotassic rocks: characteristics, classification and constraints for petrogenetic modelsEarth Science Reviews, Vol.24, pp. 81-134GlobalClassification, Petrogenesis
DS1993-1657
1993
Ver Hoef, J.M.Ver Hoef, J.M., Cressie, N.Multivariable spatial predictionMathematical Geology, Vol. 25, No. 3, February pp. 219-240GlobalGeostatistics, Multivariates
DS2002-0698
2002
VeraHelffrich, G., Wiens, Vera, Barrientos, Shore ..A teleseismic shear wave splitting study to investigate mantle flow around South AfricaGeophysical Journal International, Vol.149,1,pp.F1-7., Vol.149,1,pp.F1-7.MantleGeophysics - seismics
DS2002-0699
2002
VeraHelffrich, G., Wiens, Vera, Barrientos, Shore ..A teleseismic shear wave splitting study to investigate mantle flow around South AfricaGeophysical Journal International, Vol.149,1,pp.F1-7., Vol.149,1,pp.F1-7.MantleGeophysics - seismics
DS2003-0892
2003
Vera, E.Maurice, S.D.R., Wiens, D.A., Koper, K.D., Vera, E.Crustal and upper mantle structure of southernmost South America inferred fromJournal of Geophysical Research, Vol. 08, 2, 10.1029/2001JB0001828.Asia, MantleGeophysics - seismics
DS200412-1250
2003
Vera, E.Maurice, S.D.R., Wiens, D.A., Koper, K.D., Vera, E.Crustal and upper mantle structure of southernmost South America inferred from regional waveform inversion.Journal of Geophysical Research, Vol. 08, 2, 10.1029/2001 JB0001828.AsiaGeophysics - seismics
DS201212-0755
2012
Verad, C.Verad, C., Hochard, C., Stampfil, G.Non-random distribution of euler poles: is plate tectonics subject to rotational effects?Terra Nova, in press availableMantleTectonics
DS201602-0203
2016
Verall, M.Downes, P.J., Dunkley, D.J., Fletcher, I.R., McNaughton, N.J., Rasmusson, B., Jaques, A.L., Verall, M., Sweetapple, M.T.Zirconolite, zircon and monazite-(Ce) U-Th-Pb age constraints on the emplacement, deformation and alteration history of the Cummins Range carbonatite complex, Halls Creek orogen, Kimberley region, Western Australia.Mineralogy and Petrology, In press available, 24p.AustraliaCarbonatite

Abstract: In situ SHRIMP U-Pb dating of zirconolite in clinopyroxenite from the Cummins Range Carbonatite Complex, situated in the southern Halls Creek Orogen, Kimberley region, Western Australia, has provided a reliable 207Pb/206Pb age of emplacement of 1009 ± 16 Ma. Variably metamict and recrystallised zircons from co-magmatic carbonatites, including a megacryst ~1.5 cm long, gave a range of ages from ~1043-998 Ma, reflecting partial isotopic resetting during post-emplacement deformation and alteration. Monazite-(Ce) in a strongly foliated dolomite carbonatite produced U-Th-Pb dates ranging from ~900-590 Ma. Although the monazite-(Ce) data cannot give any definitive ages, they clearly reflect a long history of hydrothermal alteration/recrystallisation, over at least 300 million years. This is consistent with the apparent resetting of the Rb-Sr and K-Ar isotopic systems by a post-emplacement thermal event at ~900 Ma during the intracratonic Yampi Orogeny. The emplacement of the Cummins Range Carbonatite Complex probably resulted from the reactivation of a deep crustal structure within the Halls Creek Orogen during the amalgamation of Proterozoic Australia with Rodinia over the period ~1000-950 Ma. This may have allowed an alkaline carbonated silicate magma that was parental to the Cummins Range carbonatites, and generated by redox and/or decompression partial melting of the asthenospheric mantle, to ascend from the base of the continental lithosphere along the lithospheric discontinuity constituted by the southern edge of the Halls Creek Orogen. There is no evidence of a link between the emplacement of the Cummins Range Carbonatite Complex and mafic large igneous province magmatism indicative of mantle plume activity. Rather, patterns of Proterozoic alkaline magmatism in the Kimberley Craton may have been controlled by changing plate motions during the Nuna-Rodinia supercontinent cycles (~1200-800 Ma).
DS201803-0483
2018
Verard, C.Verard, C.Plate tectonic modelling: review and perspectives.Geological Magazine, in press available GlobalPlate tectonics

Abstract: Since the 1970s, numerous global plate tectonic models have been proposed to reconstruct the Earth's evolution through deep time. The reconstructions have proven immensely useful for the scientific community. However, we are now at a time when plate tectonic models must take a new step forward. There are two types of reconstructions: those using a ‘single control’ approach and those with a ‘dual control’ approach. Models using the ‘single control’ approach compile quantitative and/or semi-quantitative data from the present-day world and transfer them to the chosen time slices back in time. The reconstructions focus therefore on the position of tectonic elements but may ignore (partially or entirely) tectonic plates and in particular closed tectonic plate boundaries. For the readers, continents seem to float on the Earth's surface. Hence, the resulting maps look closer to what Alfred Wegener did in the early twentieth century and confuse many people, particularly the general public. With the ‘dual control’ approach, not only are data from the present-day world transferred back to the chosen time slices, but closed plate tectonic boundaries are defined iteratively from one reconstruction to the next. Thus, reconstructions benefit from the wealth of the plate tectonic theory. They are physically coherent and are suited to the new frontier of global reconstruction: the coupling of plate tectonic models with other global models. A joint effort of the whole community of geosciences will surely be necessary to develop the next generation of plate tectonic models.
DS201902-0331
2019
Verard, C.Verard, C.Plate tectonic modelling: review and perspectives.Geological Magazine, Vol. 156, 2, pp. 208-241.Mantleplate tectonics

Abstract: Since the 1970s, numerous global plate tectonic models have been proposed to reconstruct the Earth's evolution through deep time. The reconstructions have proven immensely useful for the scientific community. However, we are now at a time when plate tectonic models must take a new step forward. There are two types of reconstructions: those using a ‘single control’ approach and those with a ‘dual control’ approach. Models using the ‘single control’ approach compile quantitative and/or semi-quantitative data from the present-day world and transfer them to the chosen time slices back in time. The reconstructions focus therefore on the position of tectonic elements but may ignore (partially or entirely) tectonic plates and in particular closed tectonic plate boundaries. For the readers, continents seem to float on the Earth's surface. Hence, the resulting maps look closer to what Alfred Wegener did in the early twentieth century and confuse many people, particularly the general public. With the ‘dual control’ approach, not only are data from the present-day world transferred back to the chosen time slices, but closed plate tectonic boundaries are defined iteratively from one reconstruction to the next. Thus, reconstructions benefit from the wealth of the plate tectonic theory. They are physically coherent and are suited to the new frontier of global reconstruction: the coupling of plate tectonic models with other global models. A joint effort of the whole community of geosciences will surely be necessary to develop the next generation of plate tectonic models.
DS201602-0191
2015
Veraswarmy, K.K.Azeez, A., Veraswarmy, K.K., Gupta, K., Babu, A.K.The electrical resistivity structure of lithosphere across the Dharwar craton nucleus and Coorg block of South Indian Shield: evidence of collision and modified and preserved lithosphere.Journal of Geophysical Research, Vol. 120, 10, pp. 6698-6721.IndiaGeophysics - craton

Abstract: Magnetotelluric-derived two-dimensional lithospheric resistivity structure of the western Dharwar craton (WDC) and adjoining Coorg block indicates isolated low-resistivity zones in the crust and three striking upper mantle conductive features within the highly resistive Archean lithosphere. The crustal conductors in the WDC show good spatial correlation with the exposed supracrustal rocks conformable with the relic schist belt channels having conductive mineral grains. Conductive zones within the Coorg crust might be related to the relatively young (933?Ma) metamorphic processes in the area and/or possible fluids derived from the Cretaceous passage of Reunion plume in the proximity of Coorg area. A near-vertical conductive structure extending from the lower crust into the upper mantle coincides with the transition zone between Coorg and WDC. This is interpreted as the suture zone between the two tectonic blocks and provides evidence for the individuality of the two Archean terrains. An anomalous upper mantle conductive zone found beneath the craton nucleus may indicate a modified cratonic lithosphere. This could have been derived due to the collision between Coorg and WDC and possibly survived by the subsequent multiple episodes of melt and fluid infiltration processes experienced in the region. Thick (~190?km) and preserved lithosphere is mapped at the eastern segment of WDC. Resistive lithosphere of ~125?km thickness is imaged for the Coorg block.
DS200512-1138
2005
Verati, C.Verati, C., Bertrand, H., Fraud, G.The farthest record of the Central Atlantic Magmatic Province into West Africa craton: precise 40 Ar 39 Ar dating and geochemistry of Taoudenni basin intrusivesEarth and Planetary Science Letters, Vol. 235, 1-2, pp. 391-407.Africa, MaliMagmatism
DS202001-0030
2019
Verati, C.Najih, A., Montero, P., Verati, C., Chabou, M.C., Fekkak, A., Baidder, L., Ezzouhairi, H., Bea, F., Michard, A.Initial Pangean rifting north of the West African craton: insights from late Permian U-Pb and 40Ar/39Ar dating of alkaline magmatism from the eastern Anti-Atlas ( Morocco).Journal of Geodynamics, Vol. 132, 17p.Africa, Moroccocamptonites

Abstract: Numerous mafic dykes, sills and laccoliths crop out in the southern part of the Tafilalt basin (Eastern Anti-Atlas, Morocco). These rocks intrude the mildly folded Ordovician to Early Carboniferous formations, consisting mainly of lamprophyric dolerites and camptonites with minor gabbros and syenodiorites. Previous geochemical studies have shown that the Tafilalt magmatism of sodic-alkaline affinity has been produced by low degrees of partial melting from an enriched deep mantle source within the garnet stability field. However, the age and the geodynamic context of these rocks were presently unknown since no isotopic dating had so far been made of the Tafilalt dolerites. To resolve this issue, we present here the first 40Ar/39Ar biotite and U-Pb zircon dating from the Tafilalt alkaline magmatism. Three samples (biotite separates) yielded well-defined 40Ar/39Ar plateau ages of 264.2?±?2.7 Ma, 259.0?±?6.3 Ma and 262.6?±?4.5 Ma whereas 206Pb/238U dating of zircon from one of these samples yielded an age of 255?±?3 Ma. These ages coincide within the dating error, and indicate that this magmatism occurred in the late Permian. Considering geochronological and geochemical data, we propose that the Tafilalt magmatism reflects an early-rift magmatic activity that preceded the Triassic rifting heralded by the Central Atlantic Magmatic Province. This magmatic activity is recorded in both sides of the future Atlantic Ocean by small-volume alkaline magmatism that started in the late Permian and extends into the Triassic. The alkaline magmas are probably generated in response to an increase in the mantle potential temperature underneath the Pangea supercontinent.
DS2000-0434
2000
Verba, M.L.Isanina, E.V., Verba, M.L., Ivanova, N.M., KazanskyDeep structure and seismogeological boundaries of the Pechenga District, Baltic Shield -Geol. Ore Dep., Vol. 42, No. 5, pp. 429-39.Russia, Baltic ShieldTectonics, seismics
DS1960-0757
1966
Verband Der Edelstein Und DiamantenindustrieVerband Der Edelstein Und DiamantenindustrieEdelsteine. #3Idar-oberstein., 31P.GlobalKimberley, Diamonds Notable
DS1960-0409
1963
Verbickaya, N.P.Verbickaya, N.P.Stratigraphie et Lithogie des Formations Alluviales des Regions Diamantiferes du Versant Occidental de ; Oural Moyen.La Chronique Des Mines Coloniales, No. 316, P. 46.Russia, UralsStratigraphy, Lithology, Alluvial Diamond Placers
DS2000-0979
2000
Verburg, P.Verburg, P.Diamonds ain't forever.... Dia Met selling their company?Overview of diamond markets and branding.Can. Business, Nov. 13, pp. 54-5, 65-66.Northwest TerritoriesNews item, Dia Met Minerals Ltd.
DS200512-0339
2005
Verchocsky, A.B.Gilmour, J.D., Verchocsky, A.B., Fisenko, A.V., Holland, G., Turner, G.Xenon isotopes in size separated nanodiamonds from Efremovka: 129 Xe, Xe-P3 and Xe-P6.Geochimica et Cosmochimica Acta, Vol. 69, 16, Aug.15, pp. 4133-4148.TechnologyNanodiamonds, geochronology, degassing events
DS1995-1252
1995
VerchovskyMilledge, H.J., Shelkov, D., Pillinger, C.T., VerchovskyProblems associated with the existence of carbonadoProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 387-388.GlobalCarbonado, Morphology
DS2002-0461
2002
VerchovskyFisenko, A.V., Verchovsky, Semenova, PillingerInterstellar diamond in the Efremovka CV3 chondrite: pyrolysis of different size fractions of grains.Geochemistry International, Vol.40,3,pp.209-28.GlobalMetorite - diamond
DS200912-0794
2009
Verchovsky, A.Verchovsky, A., Tolstikhin, I.N and C isotopic compositons in high 3He Kola plume rocks.Goldschmidt Conference 2009, p. A1378 Abstract.Russia, Kola PeninsulaCarbonatite
DS202112-1921
2021
Verchovsky, A.Buikin, A.J., Hopp, J., Verchovsky, A., Trieloff, M.The sources and evolution of fluid phases of Guli Massif carbonatites ( West Siberia): summarizing of noble gases, N2, CO2, H2O stepwise crushing data.Petrology, Vol. 29, 6, pp. 657-675. pdfRussia, Siberiadeposit - Guli Massif

Abstract: Here we present summarizing of isotopic compositions and element ratios of noble gases, nitrogen, carbon and hydrogen in carbonatites of different generations of the Guli massif (West Siberia, Russia) obtained by stepwise crushing. The data point to the subcontinental lithospheric mantle (SCLM) as a primary source of the fluid phase in Guli carbonatites. However, the estimated 40Ar/36Ar ratio in the Guli mantle source of about 5400 is similar to the Kola plume value of 5000 ± 1000 (Marty et al., 1998). One explanation of such a low estimated 40Ar/36Ar ratio in the mantle end-member with SCLM type helium (4??/3?? ~ 120000) and neon (21N?/22N?mantle ~ 0.7) is an admixture of atmospheric argon to the local mantle source. This assumption is supported by the Ar-Ne systematics as well as by the data for hydrogen isotopic composition. Early carbonatite differs significantly from the later ones by the concentration of highly volatile components, as well as by the isotopic compositions of carbon (CO2), argon, and hydrogen (H2O). The mantle component dominated in fluids at the early formation stages of the Guli massif rocks, whereas the late stages of carbonatite formation were characterized by an additional fluid source, which introduced atmospheric argon and neon, and most likely a high portion of CO2 with isotopically heavy carbon. The argon-neon-hydrogen isotope systematics suggest that the most plausible source of these late stage fluids are high temperature paleometeoric waters. The absence of a plume signature could be explained in terms that Guli carbonatites have been formed at the waning stage of plume magmatic activity with an essential input of SCLM components.
DS1993-1658
1993
Verchovsky, A.B.Verchovsky, A.B., Ott, U., Begemann, F.Implanted radiogenic and other noble gases in crustal diamonds from northern Kazakhstan.Earth and Planetary Science Letters, Vol. 120, No. 3-4 December pp. 87-102.Russia, KazakhstanBlank
DS1995-1694
1995
Verchovsky, A.B.Sehlkov, D., Verchovsky, A.B., Milledge, H.J., PillingerCarbonado: a comparison between Brazilian and Ubangui sources based on carbon and nitrogen isotopes.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 518-520.Brazil, Central African RepublicCarbonado, Geochronology
DS1998-1331
1998
Verchovsky, A.B.Shelkov, D.A., Verchovsky, A.B., Pillinger, C.T.The radial distribution of implanted and trapped 4He in single diamond crystals and implications for carbonadoChemical Geology, Vol. 149, No. 1-2, July 10, pp. 109-116.GlobalCarbonado, Diamond morphology
DS201112-0067
2011
Verchovsky, A.B.Basu, S., Mikhail, S., Jones, A.P., Verchovsky, A.B.Comparing carbon isotopic signatures between meteorites and terrestrial mantle samples: need for reassessment of carbon composition of Earth's mantle.Goldschmidt Conference 2011, abstract p.497.MantleCarbonatite, diamonds
DS201112-0126
2011
Verchovsky, A.B.Buikin, A.I., Verchovsky, A.B., Grinenko, V.A., Kogarko, L.N.The first stepwise crushing dat a on C, N and Ar isotopic and elemental ratios in Guli carbonatites.Goldschmidt Conference 2011, abstract p.596.Russia, YakutiaMaymecha-Kotuy magmatic complex
DS201312-0058
2013
Verchovsky, A.B.Basu, S., Jones, A.P., Verchovsky, A.B., Kelley, S.P., Stuart, F.M.An overview of noble gas (He,Ne, Ar, Xe) contents and isotope signals in terrestrial diamond.Earth Science Reviews, Vol. 126, pp. 370-389.TechnologyMineral chemistry
DS201312-0126
2012
Verchovsky, A.B.Carmody, L., Jones, A.P., Mikhail, S., Bower, D.M., Steele, A., Lawrence, D.M., Verchovsky, A.B., Buikin, A., Taylor, L.A.Is the World's only carbonatite volcano a dry anhydrous system?Geological Society of America Annual Meeting abstract, Paper 157-2, 1/2p. AbstractAfrica, TanzaniaDeposit - Oldoinyo Lengai
DS201312-0404
2013
Verchovsky, A.B.Howell, D., Stern, R.A., Griffin, W.L., Southworth, R., Mikhail, S., Stachel, T., Verchovsky, A.B., O'Reilly, S.Y., Pearson, N.J.New thermodynamic models and calculated phase equilibration temperatures in NCFMAS for basic and ultrabasic compositions through the transition zone into the uppermost lower mantle.Goldschmidt 2013, AbstractTechnologyCrystallography
DS201312-0602
2013
Verchovsky, A.B.Mikhail, S., Dobosi, G., Verchovsky, A.B., Kurat, G., Jones, A.P.Peridotitic and websteritic diamondites provide new information regarding mantle melting and metasomatism induced through the subduction of crustal volatiles.Geochimica et Cosmochimica Acta, Vol. 107, Apr. 15, pp. 1-11.MantleDiamondites
DS201412-0078
2014
Verchovsky, A.B.Buikin, A.I., Verchovsky, A.B., Sorokhtina, N.V., Kogarko, L.N.Composition and sources of volatiles and noble gases in fluid inclusions in pyroxenites and carbonatites of the Seblyar Massif, Kola Peninsula.Petrology, Vol. 22, 5, p. 507-520.Russia, Kola PeninsulaAlkalic
DS201412-0577
2014
Verchovsky, A.B.Mikhail, S., Guillermier, C., Franchi, I.A., Beard, A.D., Crispin, K., Verchovsky, A.B., Jones, A.P., Milledge, H.J.Empirical evidence for the fractionation of carbon isotopes between diamond and iron carbide from the Earth's mantle.Geochemistry, Geophysics, Geosystems: G3, Vol. 15, 4, pp. 855-866.MantleGeochronology
DS201412-0581
2014
Verchovsky, A.B.Mikhail, S., Verchovsky, A.B., Howell, D., Hutchison, M.T., Southworth, R., Thomson, A.R., Warburton, P., Jones, A.P., Milledge, H.J.Constraining the internal variability of the stable isotopes of carbon and nitrogen within mantle diamonds.Chemical Geology, Vol. 366, pp. 14-23.Africa, Russia, South America, BrazilDiamond inclusions
DS201605-0816
2016
Verchovsky, A.B.Buikin, A.I., Verchovsky, A.B., Kogarko, L.N., Grinenko, V.A., Kuznetsova, O.V.The fluid phase evolution during the formation of carbonatite of the Guli Massif: evidence from the isotope ( C, N, Ar) data.Doklady Earth Sciences, Vol. 466, 2, Feb. pp. 135-137.RussiaCarbonatite

Abstract: The first data on variations of the isotope composition and element ratios of carbon, nitrogen, and argon in carbonatites of different generations and ultrabasic rocks of the Guli massif obtained by the method of step crushing are reported. It is shown that early carbonatite differs significantly from the later ones by the concentration of highly volatile components, as well as by the isotope compositions of carbon (CO2), argon, and hydrogen (H2O). The data obtained allow us to conclude that the mantle component predominated in the fluid at the early stages of formation of rocks of the Guli massif, whereas the late stages of carbonatite formation were characterized by an additional fluid source, which introduced atmospheric argon, and most likely a high portion of carbon dioxide with isotopically heavy carbon.
DS201012-0496
2010
Verchovsky, S.Mikhail, S., Dobosi, G., Verchovsky, S., Jones, A., Kurat, G.Organic looking carbon and nitrogen isotope compositions in mantle derived diamondites: mantle fractionation vs reworked crustal organics?International Mineralogical Association meeting August Budapest, abstract p. 185.Africa, southern AfricaDiamondites
DS1999-0660
1999
VercoeShee, S.R., Vercoe, Wyatt, Hwang, Campbell, ColganDiscovery and geology of the Nabberu kimberlite province, western Australia. Capicorn Orogeny7th International Kimberlite Conference Nixon, Vol. 2, pp. 764-72.Australia, Western AustraliaMineral chemistry, melnoites. SiroteM., Deposit - Nabberu - microdiamonds
DS201807-1509
2018
Vercoe, S.Lock, N., Vercoe, S.Jwaneng - the untold story of the discovery of the world's richest diamond mine.SAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 185-202.Africa, Botswanadeposit - Jwaneng
DS201808-1765
2018
Vercoe, S.Lock, N., Vercoe, S.Jwaneng - the untold story of the discovery of the world's richest diamond mine.SAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., 14 ppts.Africa, Botswanadeposit - Jwaneng
DS202008-1456
2018
Vercoe, S.Vercoe, S., Lock, N.Our Jwaneng story.Botswana Journal of Earth Sciences, Vol. 7, pp. 3-12. pdfAfrica, Botswanadeposit - Jwaneng

Abstract: When Leon Daniels first contacted us, and others, about the Botswana Diamond Exploration Conference 2017, he wrote: ‘The future of diamond exploration lies in us "old-timers" who have retired or are about to retire to inspire the next generation to go out there and make the next discoveries so vitally important for Botswana.’ Sadly, in presenting on behalf of both Stuart and I, I had to own to being one of those old-timers!
DS1998-0760
1998
Vercoe, S.C.Kiviets, G., Phillips, D., Shee, S.R., Vercoe, S.C.40 Ar-39 Ar dating of yimengite from the Turkey Well kimberlite, Australia: the oldest and the rarest.7th International Kimberlite Conference Abstract, pp. 432-34.AustraliaGeochronology, Argon, Deposit - Turkey Wells, Leonora area
DS1998-1330
1998
Vercoe, S.C.Shee, S.R., Vercoe, S.C., Wyatt, B.A., Campbell, ColganDiscovery and geology of the Nabberu kimberlite province, WesternAustralia.7th International Kimberlite Conference Abstract, pp. 800-2.AustraliaHistory, methodology, petrography, Deposit - Nabberu Province
DS201802-0280
2017
Verdel, C.Wong, J., Verdel, C., Allen, C.M.Trace element compositions of sapphire and ruby from the eastern Australian gemstone belt.Mineralogical Magazine, Vol. 81, 6, pp. 1551-1576.Australiamineralogy

Abstract: View at publisher (open access) Abstract Significant uncertainty surrounds the processes involved in the formation of basalt-hosted corundum, particularly the role that the mantle plays in corundum generation. Some previous studies have suggested that trace-element ratios (namely, Cr/Ga and Ga/Mg) are useful for distinguishing two types of corundum: “magmatic” and “metamorphic,” designations that include mantle and crustal processes. However, recent studies, including this one, have discovered transitional groups between these end-members that are difficult to classify. We used LA-ICP-MS to measure trace-element concentrations in sapphire and ruby crystals from eight alluvial deposits that span a significant length of the eastern Australian gemstone belt. Additionally, we collected LA-ICP-MS U-Pb and trace-element data from zircon megacrysts at Weldborough, Tasmania, which is also within the gemstone belt. Our sapphire and ruby results reveal a continuum in trace-element compositions, a finding that raises questions about previous classifications that ascribe corundum from basalt-hosted gemfields to either “magmatic” or “metamorphic” sources. The spatial association of basalt-related gemfields in eastern Australia with a long-lived convergent margin suggests a link between corundum formation and Al-enrichment of the mantle wedge during periods of subduction.
DS201804-0725
2018
Verdel, C.Palke, A.C., Wong, J., Verdel, C., Avila, J.N.A common origin for Thai/Cambodian rubies and blue and violet sapphires from Yogo Gulch, Montana, U.S.A?American Mineralogist, Vol. 103, pp. 469-479.United States, Montanadeposit - Yogo Gulch

Abstract: A wide number of genetic models have been proposed for volcanically transported ruby and sapphire deposits around the world. In this contribution we compare the trace element chemistry, mineral and melt inclusions, and oxygen isotope ratios in blue to reddish-violet sapphires from Yogo Gulch, Montana, U.S.A., with rubies from the Chantaburi-Trat region of Thailand and the Pailin region of Cambodia. The similarities between Thai/Cambodian rubies and Yogo sapphires suggest a common origin for gem corundum from both deposits. Specifically, we advance a model whereby sapphires and rubies formed through a peritectic melting reaction when the lamprophyre or basalts that transported the gem corundum to the surface partially melted Al-rich lower crustal rocks. Furthermore, we suggest the protolith of the rubies and sapphires was an anorthosite or, in the case of Thai/Cambodian rubies, an anorthosite subjected to higher pressures and converted into a garnet-clinopyroxenite. In this model the rubies and sapphires are rightfully considered to be xenocrysts in their host basalts or lamprophyre; however, in this scenario they are not "accidental" xenocrysts but their formation is intimately and directly linked to the magmas that transported them to the surface. The similarities in these gem corundum deposits suggests that the partial melting, non-accidental xenocryst model may be more wide-reaching and globally important than previously realized. Importantly, in both cases the gem corundum has an ostensibly "metamorphic" trace element signature, whereas the presence of silicate melt (or magma) inclusions shows they ought to be considered to be "magmatic" rubies and sapphires. This discrepancy suggests that existing trace element discriminant diagrams intended to separate "metamorphic" from "magmatic" gem corundum ought to be used with caution.
DS201804-0753
2018
Verdel, C.Wong, J., Verdel, C., Allen, C.M.Trace element compositions of sapphire and ruby from the eastern Australian gemstone belt.Mineralogical Magazine, Vol. 81, 6, pp. 1551-1576.Australia, Tasmaniacorundum classification

Abstract: Significant uncertainty surrounds the processes involved in the formation of basalt-hosted corundum, particularly the role that the mantle plays in corundum generation. Some previous studies have suggested that trace-element ratios (namely, Cr/Ga and Ga/Mg) are useful for distinguishing two types of corundum: ‘magmatic’ and ‘metamorphic’, designations that include mantle and crustal processes. However, recent studies, including this one, have discovered transitional groups between these end-members that are difficult to classify. We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to measure trace-element concentrations in sapphire and ruby crystals from eight alluvial deposits that span a significant length of the eastern Australian gemstone belt. Additionally, we collected LA-ICP-MS U-Pb and trace-element data from zircon megacrysts at Weldborough, Tasmania, which is also within the gemstone belt. Our sapphire and ruby results reveal a continuum in trace-element compositions, an observation that raises questions regarding previous classifications that ascribe corundum from basalt-hosted gemfields to either ‘magmatic’ or ‘metamorphic’ sources. The spatial association of basalt-related gemfields in eastern Australia with a long-lived convergent margin suggests a link between corundum formation and Al-enrichment of the mantle wedge during periods of subduction.
DS201312-0265
2013
Verdoux, P.Fernandez, L., Bosch, D., Elmessbahi, H., Bodinier, J.L., Dautra, J.M., Verdoux, P.Lithosphere-asthenosphere interactions (Middle Atlas (Morocco): geochemical highlights.Goldschmidt 2013, AbstractAfrica, MoroccoXenoliths
DS1994-0450
1994
Verdoya, M.Dragoni, M., Pasquale, V., Verdoya, M., CVhiozzi, P.Rheological consequences of the lithospheric thermal structure in the Fennoscandian shield.Global and Planetary Change, Vol. 8, pp. 113-126.GlobalLithosphere, Structure
DS2001-0892
2001
Verdoya, M.Pasquale, V., Verdoya, M., Chiozzi, P.Heat flux and seismicity in the Fennoscandian ShieldPhysics of the Earth and Planetary Interiors, Vol. 126, No. 3-4, Nov. 1, pp. 147-62.Finland, Sweden, Baltica, FennoscandiaGeophysics - seismics, Geothermometry
DS1996-0683
1996
Verdurmen, E.A.T.Jelsma, H.A., Vinyu, M.L., Verdurmen, E.A.T.Constraints on Archean crustal evolution of the Zimbabwe craton: a uranium-lead (U-Pb) (U-Pb)zircon, samarium-neodymium (Sm-Nd),lead-lead studyChemical Geology, Vol. 129, No. 3/4, July 29, pp. 55-81Zimbabwe, South AfricaGeochronology, Craton
DS1989-1242
1989
Verdurmen, E.A.Th.Priem, H.N.A., Bon, E.H. , Verdurmen, E.A.Th., Bettencourt, J.S.rubidium-strontium (Rb-Sr) chronology of Precambrian crustal evolution in Rondonia (western margin of the Amazonian craton),BrasilJournal of South American Earth Sciences, Vol. 2, No. 2, pp. 162-170BrazilGeochronology, Amazonian craton
DS2001-0735
2001
Verennikov, N.Marwick, A.J., Downes, H., Verennikov, N.The lower crust of southeast Belarus: petrological, geophysical and geochemical constraints from xenoliths.Tectonophysics, Vol. 339, No. 1-2, pp. 215-37.RussiaPetrology, Xenoliths
DS202111-1759
2021
Vereshchagin, O.S.Britvin, S., Vlasenko, N.S., Aslandukov, A., Aslandova, A., Dubovinsky, L., Gorelova, L.A., Krzhizhanvskaya, M.G., Vereshchagin, O.S., Bocharov, V.N., Shelukina, Y.S., Lozhkin, M.S., Zaitsev, A.N., Nestola, F.Natural cubic perovskite, Ca(Ti,Si,Cr) O 3-delta, a versatile potential host rock-forming and less common elements up to Earth's mantle pressure.American Mineralogist, doi:10.2138/am-2022-8186 in pressMantleperovskite

Abstract: Perovskite, CaTiO3, originally described as a cubic mineral, is known to have a distorted (orthorhombic) crystal structure. We herein report on the discovery of natural cubic perovskite. This was identified in gehlenite rocks occurring in a pyrometamorphic complex of the Hatrurim Formation (the Mottled Zone), in the vicinity of the Dead Sea, Negev Desert, Israel. The mineral is associated with native ?-(Fe,Ni) metal, schreibersite (Fe3P) and Si-rich fluorapatite. The crystals of this perovskite reach 50 ?m in size and contain many micron sized inclusions of melilite glass. The mineral contains significant amounts of Si substituting for Ti (up to 9.6 wt.% SiO2) corresponding to 21 mol.% of the davemaoite component (cubic perovskite-type CaSiO3), in addition to up to 6.6 wt.% Cr2O3. Incorporation of trivalent elements results in the occurrence of oxygen vacancies in the crystal structure; this being the first example of natural oxygen-vacant ABO3 perovskite with the chemical formula Ca(Ti,Si,Cr)O3-? (? ~ 0.1). Stabilization of cubic symmetry (space group Pm?3m) is achieved via the mechanism not reported so far for CaTiO3, namely displacement of an oxygen atom from its ideal structural position (site splitting). The mineral is stable at atmospheric pressure to 1250±50 °C; above this temperature its crystals fuse with the embedded melilite glass, yielding a mixture of titanite and anorthite upon melt solidification. The mineral is stable upon compression to at least 50 GPa. The a lattice parameter exhibits continuous contraction from 3.808(1) Å at atmospheric pressure to 3.551(6) Å at 50 GPa. The second-order truncation of the Birch-Murnaghan equation of state gives the initial volume V0 equal to 55.5(2) Å3 and room temperature isothermal bulk modulus K0 of 153(11) GPa. The discovery of oxygen-deficient single perovskite suggests previously unaccounted ways for incorporation of almost any element into the perovskite framework up to pressures corresponding to those of the Earth’s mantle.
DS202102-0233
2021
Verevkin, S.P.White, M.A., Kahwaji, S., Freitas, V.L.S., Siewert, R., Weatherby, J.A., Ribeiro da Silva, M.D.M.C., Verevkin, S.P., Johnson, E.R., Zwanziger, J.W.The relative thermodynamic stability of diamond and graphite.Angewandte Chemie International, Vol. 60, 3, pp. 1546-1549. pdfGlobaldiamond, graphite

Abstract: Recent density?functional theory (DFT) calculations raised the possibility that diamond could be degenerate with graphite at very low temperatures. Through high?accuracy calorimetric experiments closing gaps in available data, we reinvestigate the relative thermodynamic stability of diamond and graphite. For T<400 K, graphite is always more stable than diamond at ambient pressure. At low temperatures, the stability is enthalpically driven, and entropy terms add to the stability at higher temperatures. We also carried out DFT calculations: B86bPBE?25X?XDM//B86bPBE?XDM and PBE0?XDM//PBE?XDM results overlap with the experimental ?T?S results and bracket the experimental values of ?H and ?G, displaced by only about 2× the experimental uncertainty. Revised values of the standard thermodynamic functions for diamond are ?fHo=?2150±150 J?mol?1, ?fSo=3.44±0.03 J?K?1?mol?1 and ?fGo=?3170±150 J?mol?1.
DS1986-0760
1986
Vergamini, P.J.Smyth, J.R., Vergamini, P.J., Schultz, A.J.Mineral grain orientations in mantle eclogites determined by time of flight neutron scatteringEos, Vol. 67, No. 44, Nov. 4, p. 1190. (abstract)South AfricaRoberts Victor, Petrology
DS1991-1714
1991
Vergara, M.Thiele, R., Beccar, I., Levi, B., Nystrom, J.O., Vergara, M.Tertiary Andean volcanism in a caldera-graben settingGeologische Rundschau, Vol. 80, No. 1, pp. 179-186Andes, Chile, CordilleraStructure, Graben
DS200912-0581
2009
Verges, J.Perez-Gussinye, M., Metois, M., Fernandez, M., Verges, J., Fullea, J., Lowry, A.R.Effective elastic thickness of Africa and its relationship to other proxies for lithospheric structure and surface tectonics.Earth and Planetary Science Letters, Vol. 287, 1-2, pp. 152-167.AfricaTectonics
DS201112-0481
2011
Verges, J.Jemenez-Munt, I., Fernandez, M., Verges, J., Garcia-Castellanos, D., Fullea, J., Perez-Gussinye, M., Afonso, J.C.Decoupled crust mantle accommodation of Africa-Eurasia convergence in the NW Moroccan margin.Journal of Geophysical Research, Vol. 116, B08403, 12p.Africa, MoroccoGeophysics - density
DS202004-0525
2019
Verges, J.Kumar, A., Fernandez, M., Jimenez-Munt, I., Torne, M., Verges, J., Afonso, J.C.LitMod2D_2.0: an improved integrated geophysical petrological modeling took for the physical interpretation of upper mantle anomalies.Geochemistry, Geophysics, Geosystems, 10.1029/2019GC008777. 19p.Mantlegeophysics

Abstract: LitMod2D integrates geophysical and petrological data sets to produce the thermal, density, and seismic velocity structure of the lithosphere and upper mantle. We present a new LitMod2D_2.0 package with improvements focused on (i) updated anelastic attenuation correction for anharmonic seismic velocities, (ii) chemical composition in the sublithospheric mantle, and (iii) incorporation of sublithospheric mantle anomalies. Sublithospheric mantle anomalies can be defined with different chemical composition, temperature, seismic velocities, and a combination of them, allowing the application of LitMod2D_2.0 to regions affected by mantle upwelling, subduction, delamination, and metasomatism. We demonstrate the potential application of LitMod2D_2.0 to such regions and the sensitivity of thermal and compositional anomalies on density and seismic velocities through synthetic models. Results show nonlinearity between the sign of thermal and seismic velocity anomalies, and that S wave velocities are more sensitive to temperature whereas P wave velocities are to composition. In a synthetic example of subduction, we show the sensitivity of sublithospheric mantle anomalies associated with the slab and the corner flow on surface observables (elevation, geoid height, and gravity anomalies). A new open?source graphic user interface is incorporated in the new package. The output of the code is simplified by writing only the relevant physical parameters (temperature, pressure, material type, density, and seismic velocities) to allow the user using predefined post?processing codes from a toolbox (flexure, mineral assemblages, synthetic passive seismological data, and tomography) or designing new ones. We demonstrate a post?processing example calculating synthetic seismic tomography, Rayleigh surface?wave dispersion curves, and P wave receiver functions from the output file of LitMod2D_2.0.
DS200712-0433
2006
Vergne, J.Hetenyi, G., Cattin, R., Vergne, J., Nabelek, J.L.The effective elastic thickness of the India Plate from receiver function imaging, gravity anomalies and thermomechanical modelling.Geophysical Journal International, Vol. 167, 3, Dec. 1, pp. 1106-1108.IndiaGeophysics - gravity
DS200712-0434
2007
Vergne, J.Hetenyl, G., Cattin, R., Brunet, F., Bollinger, L., Vergne, J., Nabalek, J.L., Diament, M.Density distribution of the India plate beneath the Tibetan plateau: geophysical and petrological constraints on kinetics of lower crustal eclogitizationEarth and Planetary Science Letters, Vol. 264, 1-2, pp. 226-244.Asia, IndiaEclogite
DS2003-1421
2003
Vergnolle, M.Vergnolle, M., Pollitz, F., Calais, E.Constraints on the viscosity of the continental crust and mantle from GPS measurementsJournal of Geophysical Research, Vol. 108, B10, 2502 DOI. 1029/2002JB002374Mongolia, AsiaGeophysics - siesmics, GPS
DS2003-1422
2003
Vergnolle, M.Vergnolle, M., Pollitz, F., Calasi, E.Constraints on the viscosity of the continental crust and mantle from GPS measurementsJournal of Geophysical Research, Vol. 108, 10, ETG 15 10.1029/2002JB002374MongoliaGeophysics - seismics
DS200412-2053
2003
Vergnolle, M.Vergnolle, M., Pollitz, F., Calasi, E.Constraints on the viscosity of the continental crust and mantle from GPS measurements and postseismic deformation models in wesJournal of Geophysical Research, Vol. 108, 10, ETG 15 10.1029/2002 JB002374Asia, MongoliaGeophysics - seismics
DS1970-0821
1973
Verhagen, B.TH.Sellschop, J.P.F., Verhagen, B.TH., Mazor, E., et al.Groundwater at Orapa, Botswana, Isotopic, Chemical and Hydrogeological Studies.Johannesburg: University Witwatersrand, Npru Report., 42P.BotswanaMining Engineering, Diamond Recovery, Kimberley
DS1990-1511
1990
Verhagen, B.Th.Verhagen, B.Th., Tredoux, M., Lindsay, N.M., Sellschop, J.P.F., von Sails PerchImplications of isotopic and other geochemical dat a from Cretaceous-Tertiary transition in southern AfricaChemical Geology, Vol. 80, pp. 319-325South AfricaGeochemistry, Cretaceous-Tertiary transition
DS1975-1253
1979
Verheijen, P.J.T.Verheijen, P.J.T., Ajakaiye, D.E.Geophysical Anomalies Over a Pipe Suspectedly Kimberlite In the Precambrian Metamorphic Schist Belt of Northern Nigeria.Geoexploration., Vol. 17, PP. 293-303.GlobalKimberlite, Geophysics, Groundmag
DS1991-1794
1991
Verhoef, B.J.Verhoef, B.J., et al.Magnetic anomalies off West AfricaMarine Geophysical Researches, Vol. 13, pp. 81-103.West AfricaGeophysics -magnetics, Marine
DS1989-1650
1989
Verhoef, J.Woodside, J.M., Verhoef, J.Geological and tectonic framework of eastern Canada as interpretated from potential field imageryGeological Survey of Canada Paper, No. 88-36, 33p. $ 13.50AppalachiaTectonics, Remote sensing
DS1990-1512
1990
Verhoef, J.Verhoef, J., Arkani-Hamed, J.Chemical remanent magnetization of oceanic crustGeophysical Research Letters, Vol. 17, No. 11, October pp. 1945-1948GlobalGeophysics-magnetics, Crust
DS1991-1945
1991
Verhoef, J.Zonenshain, L.P., Verhoef, J., Macnab, R., Meyers, H.Magnetic imprints of continental accretion in the U.S.S.REos, Vol. 72, No. 29, July 16, pp. 305, 310RussiaGeophysics -magnetics, Tectonics
DS1995-1137
1995
Verhoef, J.Macnab, R., Verhoef, J., Roest, W., Arkani-Hamed, J.New database documents the magnetic character of the Arctic and NorthAtlanticEos, Vol. 76, No. 45, Nov. 7, p. 449, 458Arctic, Atlantic OceanGeophysics - database
DS200912-0795
2009
Verhoeven, O.Verhoeven, O., MacQuet, A., Vacher, P., Rivoldini, A., Menvielle, M., Arrial, P.A., Chiblet, G., Tarits,P.Constraints on thermal state and composition of the Earth's lower mantle from electromagnetic impedances and seismic data.Journal of Geophysical Research, Vol. 114, B3, B03302.MantleGeophysics - seismics
DS1990-1513
1990
Verhoff, J.Verhoff, J., Usow, K.H., Roest, W.R.A new method for plate reconstructions: the use of gridded dataComputers and Geosciences, Vol. 16, No. 1, pp. 51-74GlobalComputers, Gridded data sets
DS1990-1514
1990
Verhoff, J.Verhoff, J., Usow, K.H., Roest, W.R.A new method for plate reconstructions: the use of gridded dataComputers and Geosciences, Vol. 16, No. 1, pp. 51-74.GlobalTectonics - plate, Computer - Program
DS1930-0285
1938
Verhoogen, J.Verhoogen, J.Les Pipes de Kimberlite du Katanga (1938)Annual SERV. Mines COMITE SPEC. (KATANGA), Vol. 9, PP. 1-50.Democratic Republic of Congo, Central AfricaKimberlite Geology
DS1940-0018
1940
Verhoogen, J.Verhoogen, J.Les Pipes de Kimberlite du Katanga (1940)Bruxelles: Jacques Dioncie., 46P.Democratic Republic of Congo, Central AfricaKimberlite, Geology, Kimberley
DS2001-0319
2001
VerhovskyFisenko, A.V., Verhovsky, Semenova, Ivanov, PillingerThe Kaidun meteorite: interstellar diamond in the chromium and Ci carbonaceous components.Geochemistry International, Vol. 38, Suppl. 3, pp. S294-301.GlobalMeteorite, Diamond - mineralogy
DS1997-0266
1997
Verhulst, A.Demaiffe, D., Verhulst, A., Andrea, L., Nivin, V.Geochemical (major and trace elements) and neodymium Strontium isotopic study of the Kovdor carbonatites, Kola Pen.Geological Association of Canada (GAC) Abstracts, Russia, Kola PeninsulaCarbonatite, geochemistry, Deposit - Kovdor
DS1997-1205
1997
Verhulst, A.Verhulst, A., Demaiffe, D., Ohnenstetter, D., Blanc, Ph.Cathodluminescence petrography of carbonatites and associated alkaline silicate rocks from Kola Pen.Geological Association of Canada (GAC) Abstracts, POSTER.Russia, Kola PeninsulaCarbonatite
DS2000-0226
2000
Verhulst, A.Demaiffe, D., Verhulst, A., Balaganskaya, E., KirnarskyThe Kovdor carbonatitic and alkaline complex ( Kola Peninsula) evidence for multi source evolution.Igc 30th. Brasil, Aug. abstract only 1p.Russia, Kola PeninsulaCarbonatite, Deposit - Kovdor
DS2000-0727
2000
Verhulst, A.Ohnenstetter, D., Verhulst, A., et al.Cathodluminescence study of the carbonatite suites of the Kola Peninsula (Russia).Igc 30th. Brasil, Aug. abstract only 1p.Russia, Kola PeninsulaCarbonatite
DS201112-0640
2011
VerichevMalkovets, V.G., Zedgenizov, Sobolev, Kuzmin, Gibsher, Shchukina, Golovin, Verichev, PokhilenkoContents of trace elements in olivines from diamonds and peridotite xenoliths of the V.Grib kimberlite pipe ( Arkhangel'sk Diamondiferous province, Russia).Doklady Earth Sciences, Vol. 436, 2, pp. 301-307.RussiaDeposit - Grib
DS1991-0936
1991
Verichev, E.M.Kudrjavtseva, G.P., Bushueva, E.B., Vasiljeva, E.R., Verichev, E.M.Geological structure and mineralogy of the kimberlites of the Archangelsk kimberlite provinceProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 530-532RussiaDiatremes, Structure
DS1991-1751
1991
Verichev, E.M.Trukhin, V.I., Verichev, E.M., Garanin, V.K., Zhilyayeva, V.A.Magnetomineralogy of kimberlite type rocks at the South European part Of the USSR.(Russian)Izvest. Akad. Nauk SSSR, (Russian), No. 7, July pp. 39-51RussiaKimberlite, Mineralogy, geophysics, magnetics
DS1998-1536
1998
Verichev, E.M.Verichev, E.M., Sablukov, S.M., Sablukova, ZhuravlevA new tyoe of Diamondiferous kimberlite of the Zimny Berg area, pipe named after Vladimir Grib.7th International Kimberlite Conference Abstract, pp. 940-2.Russia, ArkangelskStructure, petrography, geochemistry, micaceous, Deposit - Grib
DS2003-0125
2003
Verichev, E.M.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Garanin, K.V., Kudryavtseva, G.P.Xenoliths of mantle metamorphic rocks from the Diamondiferous V. Grib pipe (8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, ArkangelskDeposit - Grib
DS2003-0745
2003
Verichev, E.M.Kostrovitsky, S.I., Verichev, E.M., Garanin, V.K., Suvorova, L.V., AschepkovMegacrysts from the Grib kimberlite Arkangelsk Province8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussia, Kola Peninsula, ArkangelskDeposit - Grib
DS2003-1202
2003
Verichev, E.M.Sablukova, L.I., Sablukov, S.M., Verichev, E.M., Golovin, N.N.Mantle xenoliths of the Grib pipe Zimny Bereg, Russia8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, ArkangelskDeposit - Grib
DS2003-1423
2003
Verichev, E.M.Verichev, E.M., Garanin, V.K., Kudryavtseva, G.P.Geology, composition, conditions of formation and technique of exploration of theGeology of Ore Deposits, Vol. 45, 4, pp. 337-361.Russia, Arkangelsk, Kola PeninsulaGenesis - Grib, comparison with Lomonosov
DS200412-0173
2003
Verichev, E.M.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Garanin, K.V., Kudryavtseva, G.P.Xenoliths of mantle metamorphic rocks from the Diamondiferous V. Grib pipe ( Arkangelsk province): petrology and genetic aspects8 IKC Program, Session 6, POSTER abstractRussia, Kola Peninsula, ArchangelMantle petrology Deposit - Grib
DS200412-1048
2004
Verichev, E.M.Kostrovitsky, S.I., Malkovets, V.G., Verichev, E.M., Garanin, V.K., Suvorova, L.V.Megacrysts from the Grib kimberlite pipe ( Arkandgelsk Province, Russia).Lithos, Vol. 77, 1-4, Sept. pp. 511-523.Russia, Archangel, Kola PeninsulaHigh chromium association, genesis
DS200412-1049
2003
Verichev, E.M.Kostrovitsky, S.I., Verichev, E.M., Garanin, V.K., Suvorova, L.V., Aschepkov, I.V., Mlovets, V., Griffin, W.L.Megacrysts from the Grib kimberlite Arkangelsk Province.8 IKC Program, Session 7, POSTER abstractRussia, Kola Peninsula, ArchangelKimberlite petrogenesis Deposit - Grib
DS200412-1715
2003
Verichev, E.M.Sablukova, L.I., Sablukov, S.M., Verichev, E.M., Golovin, N.N.Mantle xenoliths of the Grib pipe Zimny Bereg, Russia8 IKC Program, Session 6, POSTER abstractRussia, Kola Peninsula, ArchangelMantle petrology Deposit - Grib
DS200412-2054
2003
Verichev, E.M.Verichev, E.M., Garanin, V.K., Kudryavtseva, G.P.Geology, composition, conditions of formation and technique of exploration of the Vladimir Grib kimberlite pipe, a new diamond dGeology of Ore Deposits, Vol. 45, 4, pp. 337-361.Russia, Kola Peninsula, ArchangelGenesis - Grib, comparison with Lomonosov
DS200512-0096
2005
Verichev, E.M.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Kudryavtseva, G.P.The first find of kyanite eclogite in the V. Grib kimberlite pipe ( Arkangelsk Province).Doklady Earth Sciences, Vol. 402, 4, pp. 628-631.Russia, Kola Peninsula, ArchangelEclogite
DS200512-0922
2002
Verichev, E.M.Sablukov, V.S., Sablukova, L.I., Verichev, E.M.Essential types of mantle substrate in the Zimny Bereg region in connection with the formation of kimberlite hosting rounded and flat faces diamonds.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 185-202.Russia, Kola Peninsula, ArchangelDiamond genesis, morphology
DS200512-0923
2003
Verichev, E.M.Sabulukova, L.I., Sabulkov, S.M., Verichev, E.M., Golovin, N.N.Petrography and mineral chemistry of mantle xenoliths and xenocrysts from the Grib pipe, Zimny Bereg area, Russia.Plumes and problems of deep sources of alkaline magmatism, pp. 65-95.Russia, Kola Peninsula, ArchangelXenoliths - Grib
DS200612-0765
2006
Verichev, E.M.Lapin, A.V., Verichev, E.M.Kimberlites and related rocks of the Arkhangel'sk Diamondiferous province and adjacent areas: a comparative petrogeochemical analysis.Geochemistry International, Vol. 44, 8, pp. 771-790.Russia, Archangel, Kola PeninsulaPetrology - review
DS200812-0380
2008
Verichev, E.M.Galimov, E.M., Palazhchenko, O.V., Verichev, E.M., Garanin, V.K., Golovin, N.N.Carbon isotope composition of diamonds from the Archangelsk diamond province.Geochemistry International, Vol. 46, 10, pp. 961-970.Russia, Archangel, Kola PeninsulaDiamond chemistry
DS200812-0386
2008
Verichev, E.M.Garanin, V.K., Kopchikov, M.B., Verichev, E.M., Golovin, N.N.New dat a on the morphology of diamonds from tholeiite basalts of the Zimneberezhnyi ( winter Coast) area of the Arkangelsk Diamondiferous province.Moscow University Geology Bulletin, Vol. 63, 2, March-April pp. 114-118.Russia, Archangel, Kola PeninsulaDiamond morphology
DS200812-0561
2008
Verichev, E.M.Khachatryan, G.K., Palazhchenko, O.V., Garanin, V.K., Ivannikov, P.V., Verichev, E.M.Origin of disequilibrium diamond crystals from Parpinsky 1 kimberlite pipe using dat a from cathode luminescence and infra red spectroscopy.Moscow University Geology Bulletin, Vol. 63, 2, March-April pp. 86-94.RussiaDiamond morphology
DS201012-0354
2008
Verichev, E.M.Khachatryan, G.K., Palazhchenko, O.V., Garanin, V.K., Ivannikov, P.V., Verichev, E.M.Origin of disequilibrium diamond crystals from Karpinsky - 1 kimberlite pipe using dat a from cathode luminescence and infra red spectroscopy.Moscow University Geology Bulletin, Vol. 63, pp. 86-94.RussiaSpectroscopy
DS201212-0613
2012
Verichev, E.M.Sablukov, L.I., Sablukova, S.M.,Verichev, E.M., Antonov, A.V.Grospydite xenoliths from Grib pipe, kimberlites ( Arkangelsk Province, Russia).10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, Archangel, Kola PeninsulaDeposit - Grib
DS1981-0395
1981
Verichev, YE.M.Stankovskiy, A.F., Verichev, YE.M., et al.New Type of Vendian Igneous Activity in the Northern Part Of the Russian PlatformDoklady Academy of Science USSR, Earth Science Section., Vol. 247, No. 1-6, PP. 93-96.RussiaKimberlite
DS1992-1572
1992
Verichev, Ye.M.Trukhin, V.I., Verichev, Ye.M., et al.Magnetic mineralogy of kimberlite like rocks in northern European USSRPhysics of the Solid Earth, Vol. 27, No. 7, pp. 557-566.Russia, EuropeGeophysics, Mineralogy
DS200912-0796
2009
Verigeanu, D.Verigeanu, D., Hetman, C.M., Jellicoe, B., Baumgartner, M.C.Preliminary geology, mineral chemistry and diamond results from the C29/30 Candle Lake volcanic complex, Saskatchewan, Canada.Lithos, In press - available formatted 12p.Canada, SaskatchewanDeposit - Candle Lake
DS201112-1088
2006
Verigeanu, E.D.Verigeanu, E.D.A study of peridotite xenoliths from the Vogageur kimberlite, Slave Craton, Canada.Thesis: University of Alberta, Earth and Atmospheric Sciences Msc., 143p.Canada, Northwest TerritoriesThesis - note availability based on request to author
DS2001-0891
2001
VerkaerenPascal, M.L., Fonteilles, Verkaeren, Piret, MarinceaThe melilite bearing high temperature skarns of the Apuseni Mountains, Carpathians, Romania.Canadian Mineralogist, Vol. 39, No. 5, Oct. pp. 1405-34.RomaniaMelilite
DS1993-1648
1993
Verkaeren, J.Van Overbeke, A.C., Verkaeren, J.neodymium-bearing feldspathic nodules associated with sovite in the Lueshe carbonatite-syenite complex (N-Kivu, Zaire).Terra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 54.Democratic Republic of CongoCarbonatite, Lueshe complex
DS1995-0912
1995
Verkaeren, J.Kampata, M.D., Moreau, J., Verkaeren, J.Kimberlites from the Kundelungu Plateau, (Shaba, Zaire)Centennial Geocongress (1995) Extended abstracts, Vol. 1, p. 81-84. abstractDemocratic Republic of CongoKimberlites, Mineralogy
DS1997-1196
1997
Verkaeren, J.Van Overbeke, A.C., Verkaeren, J., Demaiffe, D.The Luesche alkaline complex: petrogenesis of igneous rocks and geochemical characterization of the metasom..Geological Association of Canada (GAC) Abstracts, Democratic Republic of CongoAlkaline rocks, Metasomatism, fenitisation
DS1989-1550
1989
Verkhalo-uzky, V.N.Verkhalo-uzky, V.N.Late Precambrian mafic dyke swarms of the Aldan shieldNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 278 Abstract held June 25-July 1RussiaDyke
DS1982-0618
1982
Verkhovshaia, N.B.Verkhovshaia, N.B.On the Age of the Productive Alluvial Deposits of the Otrozhenskii Region (chukota).Doklady Academy of Sciences Nauk SSSR., Vol. 262, No. 5, PP. 1202-1204.RussiaKimberlite
DS1994-0525
1994
Verkhovskiy, A.B.Fisenko, A.V., Verkhovskiy, A.B., Semenova L.F., Shukolyukov, A.Inert gases in diamonds from Yefremovka CV3 carbonaceous chondriteDoklady Academy of Science USSR, Earth Science Section, Vol. 328, No. 1, Nov. pp. 189-194.GlobalMeteorite, Chondrite
DS1995-0544
1995
Verkhovskiy, A.B.Fisenko, A.V., Verkhovskiy, A.B., Semenova, L.F.Inert gases in interstellar diamond in the Yefremovka C3V chondriteGeochemistry International, Vol. 32, No. 2, pp. 1-12.GlobalMeteorites
DS1997-1206
1997
Verkhovsky, A.B.Verkhovsky, A.B., Milledge, H.J., Pillinger, C.T.Carbonado: a comparison between Brazilian and Ubangui sources with other forms of microcrystalline diamond..Russian Geology and Geophysics, Vol. 38, No. 2, pp. 332-340.Brazil, Central African RepublicGeochronology, carbon and nitrogen isotope, Carbonado
DS1981-0091
1981
Verkin, B.I.Bondarenko, S.I., Verkin, B.I., et al.Study of Kimberlite Pipes by Superconductor Magnetic Variation Stations.Soviet Geology And Geophysics, Vol. 22, No. 11, PP. 90-94.RussiaGeophysics, Groundmag, Emf, Kimberlite
DS1993-1659
1993
Verksler, I.V.Verksler, I.V., Nielsen, T.F.D.Origin of perovskite mineralization in ultramafic alkaline intrusionsTerra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 54.RussiaAlkaline rocks
DS200512-1139
2005
Verly, G.Verly, G.Grade control classification of ore and waste: a critical review of estimation and simulation based procedures.Mathematical Geology, Vol.37, 5, pp. 451-475.TechnologyOre reserves - not specific to diamonds
DS202104-0613
2021
Verly, G.Verly, G., Parker, H.M.Conditional simulation for mineral resource classification and mining dilution assessment from the early 1990's to now. *** Not specific to diamondsMathematical Geosciences, Vol. 53, pp. 279-300. pdfGlobalgeostatistics

Abstract: André Journel joined Stanford University in 1978, and his program grew quickly to include a dozen students from the USA, Canada, Europe, and South Africa. He was instrumental in organizing the Second International Geostatistical Conference (Tahoe ’83), during which 13 papers were presented that can be linked to his group. Out of these 13 papers, 9 were mining-related, with 7 on recoverable reserves, 2 on uncertainty, 2 on conditional simulation, and 3 on nonparametric geostatistics. A significant research effort at the time was therefore directed at change of support, global and local recoveries, and uncertainty, but future trends could also be identified, such as nonparametric geostatistics and conditional simulation. This paper is a practical review of conditional simulation as a tool to improve mineral resource estimation in the areas of uncertainty, classification, and mining selectivity or dilution, based on the authors’ experience. Some practical considerations for conditional simulation are briefly discussed. Four case studies from the early 1990s to the late 2010s are presented to illustrate some solutions and challenges encountered when dealing with real-world commercial projects.
DS1992-1603
1992
Verm, R.W.Verm, R.W.Directions in geophysical technology: a supply and demand conceptGeophysics: the leading edge of exploration, Vol. 11, No. 7, July pp. 54-56GlobalGeophysics, Supply and demand
DS1970-0441
1971
Verma, A.P.Verma, A.P.Gravity Anomalies and Basement Elevations in the Midcontinent United States.Msc. Thesis, Michigan State University, East Lansing., GlobalMid-continent
DS2001-1014
2001
Verma, B.K.Sarma, B.S.P., Verma, B.K.Aeromagnetic lineaments, basement structure and kimberlite emplacement in Andhra Pradesh, India.Geophysical Research Letters, Vol. 28, No. 22, Nov. 15, pp. 4387-90.India, Andhra PradeshGeophysics - aeromagnetics
DS201502-0083
2014
Verma, C.B.Mukherjee, A., Jha, S., Babu, E.V.S.S.K., Verma, C.B.Discovery of a kimberlite pipe near Budikonda, Dharwar craton, south India: field approaches, preliminary petrography and mineral chemistry. KL-7Journal of the Geological Society of India, Vol. 84, 6, pp. 633-644.India, South IndiaKalyandurg cluster
DS201903-0527
2019
Verma, C.B.Liao, A.C-Y., Shellnutt, J.G., Hari, K.R., Denyszyn, S.W., Vishwakarma, N., Verma, C.B.A petrogenetic relationship between 2.37 Ga boninitic dyke swarms of the Indian Shield: evidence from the Central Bastar Craton and NE Dharwar Craton.Gondwana Research, Vol. 69, pp. 193-211.Indiacraton

Abstract: The Indian Shield is cross-cut by a number of distinct Paleoproterozoic mafic dyke swarms. The density of dykes in the Dharwar and Bastar Cratons is amongst the highest on Earth. Globally, boninitic dyke swarms are rare compared to tholeiitic dyke swarms and yet they are common within the Southern Indian Shield. Geochronology and geochemistry are used to constrain the petrogenesis and relationship of the boninitic dykes (SiO2?=?51.5 to 55.7?wt%, MgO?=?5.8 to 18.7?wt%, and TiO2?=?0.30?wt% to 0.77?wt%) from the central Bastar Craton (Bhanupratappur) and the NE Dharwar Craton (Karimnagar). A single U-Pb baddeleyite age from a boninitic dyke near Bhanupratappur yielded a weighted-mean 207Pb/206Pb age of 2365.6?±?0.9?Ma that is within error of boninitic dykes from the Dharwar Craton near Karimnagar (2368.5?±?2.6?Ma) and farther south near Bangalore (2365.4?±?1.0?Ma to 2368.6?±?1.3?Ma). Rhyolite-MELTS modeling indicates that fractional crystallization is the likely cause of major element variability of the boninitic dykes from Bhanupratappur whereas trace element modeling indicates that the primary melt may be derived from a pyroxenite mantle source near the spinel-garnet transition zone. The Nd isotopes (?Nd(t)?=??6.4 to +4.5) of the Bhanupratappur dykes are more variable than the Karimnagar dykes (?Nd(t)?=??0.7 to +0.6) but they overlap. The variability of Sr-Nd isotopes may be related to crustal contamination during emplacement or is indicative of an isotopically heterogeneous mantle source. The chemical and temporal similarities of the Bhanupratappur dykes with the dykes of the Dharwar Craton (Karimnagar, Penukonda, Chennekottapalle) indicate they are members of the same giant radiating dyke swarm. Moreover, our results suggest that the Bastar and Dharwar Cratons were adjacent but likely had a different configuration at 2.37?Ga than the present day. It is possible that the 2.37Ga dyke swarm was related to a mantle plume that assisted in the break-up of an unknown or poorly constrained supercontinent.
DS202107-1115
2021
Verma, C.B.Mukerjee, A., Tiwari, P., Verma, C.B., Babu, E.V.S.S.K., Sarathi, J.P.Native gold and Au-Pt alloy in eclogite xenoltihs of Kalyandurg KL-2 kimberlite, Anantapur district, South India.Journal of the Geological Society of India, Vol. 97, pp. 567-570.Indiadeposit - Kalyandurg

Abstract: The paper pertains to the studies carried out on the eclogitic xenoliths of KL-2 kimberlite of Kalyandurg kimberlite cluster in south India. Petrographic studies revealed bi-mineralic and kyanite-bearing eclogitic xenoliths in KL-2 kimberlite. The bimineralic and kyanite-bearing eclogites of Kalyandurg KL-2 kimberlite pipe show variation in modal proportion of garnet, omphacite, clinopyroxene and kyanite. The paper reports discovery of native gold grains and Au-Pt alloy in the kyanite-bearing eclogite xenoliths of KL-2 kimberlite. The flaky gold grains occurring in the matrix of kyanite-bearing eclogite are homogeneous and two grains of Au-Pt alloy with Au and Pt in the proportion of 9.8:1.2 are also present. This is the first report of gold and gold-platinum alloy specs from eclogitic xenoliths of Indian kimberlites.
DS202106-0932
2021
Verma, D.Dhote, P., Bhan, U., Verma, D.Genetic model of carbonatite hosted rare earth elements mineralization from Ambadongar carbonatite complex, Deccan Volcanic Province, India.Ore Geology Reviews, Vol. 135, 104215, 22p. PdfIndiadeposit - Ambadongar

Abstract: Carbonatites and associated alkaline rocks are the primary sources for REE mineralization. The Ambadongar Carbonatite Complex (ADCC) from NW Deccan Volcanic Province (DVP) constitutes the largest Carbonatite Associated REE Deposits (CARD) in India. ADCC belongs to the final stages of the Late Cretaceous alkaline-carbonatite magmatism associated with main Deccan basalt volcanic activity. The ADCC is an envisioned diatreme structure in which four carbonatitic phases are recognized, mainly calcio-carbonatites and ferro-carbonatites. Each successive carbonatite phase shows higher REE enrichment. The primary REE mineralization with bastnäsite as the dominant REE phase is hosted by pervasive hydrothermally altered ferro-carbonatite plugs. The secondary mineralogy formed with barites in the main orebody during late- to post-magmatic hydrothermal fluid alteration is fluorite, quartz, ankerite, and other REE-bearing minerals like bastnäsite, parisite, synchysite, strontianite, florencite, monazite and columbite. Carbonatite samples contain 18.61% to 52.42% of CaO, and the LOI varies from 5.28% to 38.79%. Most can be classified as calcio-carbonatites. Since all the samples also contain an appreciable amount of Fe2O3 (4.13% to 20.20%) and MnO (0.07% to 5.46%), some may be classified as ferro-carbonatites. Total REE content varies from 0.6 to 4%, with a high Ce concentration and LREE/HREE ratio. The highest values for La, Ce, Pr, and Nd are 1.95%, 1.56%, 0.16%, and 0.45%, respectively. Metasomatism of SCLM from asthenospheric melts followed by the low degree partial melting of the SCLM region is responsible for fertile carbonatite generation in ADCC. The multiphase liquid immiscibility of carbonatite melts from carbonate-silicate magma followed by immiscibility of REE rich carbonatite melt and REE deficient fluoride-rich aqueous fluids explain the higher level of REE enrichment in each successive phases of carbonatites in ADCC. The mineralizing fluids were probably the result of residual magmatic volatiles that brought mainly REE and later SiO2 into the overprinted rocks. Ambadongar carbonatites' stable isotopic compositions agree with a magmatic origin (?13C = ?4.1 ± 1.9‰ [PDB] and ?l8O = 10.3 ± 1.7‰ [SMOW]). The C-O stable isotopic modeling indicates re-equilibration under hydrothermal conditions between 180 °C and 70 °C. Significant amounts of REE fluorocarbonate minerals, relatively Sr- and Th-rich, were deposited during re-equilibration. The REE fluorocarbonate bastnäsite-(Ce) occurs as late individual crystals, overgrown on the synchysite and parisite polycrystals. Textural and chemical reactions between the REE fluorocarbonates provide insights into rare-earth elements' mobility during fluid-rock interaction. Early crystallization of synchysite/parisite indicates the high activity of Ca2+, OH?, (SO4)2?, Al and Si in the fluid. Later, the fluid was characterized by increased activity of F?, (SO4)2?, REE and Si, and decreased activity of Ca2+ as reflected in the association of barite, fluorite, quartz, and bastnäsite typical of strongly overprinted ferro-carbonatites. Re-equilibration and recrystallization of the primary minerals in the presence of OH?, (SO4)2?, F?, REE, Al, and Si carried in solution by the hydrothermal fluid is the leading cause behind the refixing of REE in the form of REE fluorocarbonate in REE rich ferro-carbonatites.
DS201701-0036
2017
Verma, K.Verma, K.Precambrian plate tectonic setting of Africa from multidimensional discrimination diagrams.Journal of African Earth Sciences, Vol. 125, pp. 137-150.AfricaTectonics

Abstract: New multi-dimensional discrimination diagrams have been used to identify plate tectonic setting of Precambrian terrains. For this work, nine sets of new discriminant-function based multi-dimensional discrimination diagrams were applied for thirteen case studies of Precambrian basic, intermediate and acid magmas from Africa to highlight the application of these diagrams and probability calculations. The applications of these diagrams indicated the following results: For northern Africa: to Wadi Ghadir ophiolite, Egypt indicated an arc setting for Neoproterozoic (746 ± 19 Ma). For South Africa: Zandspruit greenstone and Bulai pluton showed a collision and a transitional continental arc to collision setting at about Mesoarchaean and Neoarchaean (3114 ± 2.3 Ma and 2610-2577 Ma); Mesoproterozoic (1109 ± 0.6 Ma and 1100 Ma) ages for Espungabera and Umkondo sills were consistent with an island arc setting. For eastern Africa, Iramba-Sekenke greenstone belt and Suguti area, Tanzania showed an arc setting for Neoarchaean (2742 ± 27 Ma and 2755 ± 1 Ma). Chila, Bulbul-Kenticha domain, and Werri area indicated a continental arc setting at about Neoproterozoic (800-789 Ma); For western Africa, Sangmelima region and Ebolowa area, southern Cameroon indicated a collision and continental arc setting, respectively for Neoarchaean (?2800-2900 Ma and 2687-2666 Ma); Finally, Paleoproterozoic (2232-2169 Ma) for Birimian supergroup, southern Ghana a continental arc setting; and Paleoproterozoic (2123-2108 Ma) for Katiola-Marabadiassa, Côte d'Ivoire a transitional continental arc to collision setting. Although there were some inconsistencies in the inferences, most cases showed consistent results of tectonic settings. These inconsistencies may be related to mixed ages, magma mixing, crustal contamination, degree of mantle melting, and mantle versus crustal origin.
DS201801-0002
2017
Verma, M.B.Balasubramani, S., Sahoo, P., Bhattacharya, D., Rengarajan, M., Thangavel, S., Bhatt, A.K., Verma, M.B., Nanda, L.K.A note on anomalous concentration of scandium in the Pakkanadu alkaline complex, Salem District, Tamil Nadu, India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 46.Indiaalkaline rocks

Abstract: Pakkanadu Alkaline complex (PAC) of Neoproterozoic age is located at the southwestern end of Dharmapuri rift/shear zone on the northern part of southern granulitic terrain in Tamil Nadu, India. PAC mainly comprises carbonatite-syenitepyroxenite suite of rocks. Syenite is the predominant rock exposed on the eastern and western part of the explored area with enclaves of pyroxenite and dunite. The carbonatite (sovite) occurs as thin veins/bands and discontinuous lenticular bodies intrusive into highly deformed biotite schist that is considered as the fenitised product of pyroxenite traceable over a strike length of 1.5 km. Petromineralogical study of the biotite schist, pyroxenite containing carbonatite rock and carbonatite indicated presence of monazite, allanite, sphene and betafite as the main radioactive minerals occurring as inclusion within biotite or as discrete mineral grains. Other ore minerals are apatite, thorite, titanite, rutile and barite. Chloritisation, hematitisation, silicification and calcitisation are the main wall rock alteration observed in pyroxenite and syenite. Sub-surface exploration carried out by Atomic Minerals Directorate (AMD) in PAC revealed that biotite schist (n=166) contains anomalously high concentration of Scandium (11-1275 ppm, av.161 ppm), REE (67-58275 ppm, av. 14836 ppm,) and V (5-620 ppm, av. 127 ppm, with carbonatite veins and syenite (n=149) contain scandium (10-462 ppm, av.71 ppm,), REE (18-57510 ppm, av. 4106 ppm) and V (1-285 ppm, av. 48 ppm). In these rocks, LREE (12.5-57670 ppm, av. 9617 ppm, n=315) shows enrichment over HREE (7.1-774 ppm, av. 173 ppm, n=315). The concentration of Scandium (Av. 166 and 71 ppm in biotite schist and syenite respectively) is anomalous as compared to its crustal abundance (22 ppm). Geochemical analyses of the rock indicate that the radioactive biotite schist, pyroxenite containing carbonatite veins generally shows higher Sc and REE concentrations as compared to those of the other rocks (syenite). However, there is no significant correlation between REE and Sc. The higher concentration of scandium in PAC is possibly due to selective partitioning of it into minerals like apatite, pyrochlore, allanite, monazite and other REE bearing phases, apart from its concentration in the ferromagnesian minerals. Scandium rarely concentrates in nature as independent ore mineral. The demand for the metal is very high due to multiple high value commercial uses as an alloy with aluminum, specifically in aerospace and automobile industry, besides, in solid oxide fuel cells (SOFC) in electrical industries. Eight boreholes drilled as part of the preliminary subsurface exploration in PAC, covering an area of 0.05 sq. km, indicated an elevated Scandium content of about 6 times that of the average crustal abundance.
DS201801-0041
2017
Verma, M.B.Nanda. L.K., Verma, M.B., Purohit, R.K., Khandelwal, M.K., Rai, S.D., Mundra, K.L.LREE and Nb multi metal potentiality of the Amba Dongar carbonatite complex, Chhota Udepur district, Gujarat.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 43-44.Indiadeposit - Amba Dongar

Abstract: Rare earth elements (REE) are used in science innovations, due to their unique magnetic, fluorescent and chemical properties. REE are key components in rnany technological devices, like hybrid rechargeable batteries, catalysts, glass polishing, magnets, lasers, TV colour components, superconductors, ceramics etc. They are in great demand for hybrid cars, CD, cameras and high end defence systems. Similarly, niobium (Nb) finds its usage in diverse high tech applications including atomic energy. With increasing technological applications of REE and Nb, their global demand has enhanced over the years. To keep pace with the current demand, many carbonatite complexes in India including the Amba Dongar were revisited to assess their REE and Nb content. Amba Dongar is a classic carbonatite-alkalic rock complex of the Deccan basalt plateau and is emplaced in close proximity to Narmada rift zone. The main rock types of carbonatite affinity include sovite (calcium carbonatite), ankerite (Fe-Mg•Mn carbonatite), siderite (Fe carbonatite), carbonatite breccia (mixed rock. fragments with carbonate cement) etc. Sovite forms a large ring-dyke (nearly 1.5 km dia.) surrounding an incomplete ring of carbonatite breccia. Plugs of ankeritic carbonatite intrude the sovite. To assess rare metal and REE potential of the carbonatite complex geological and radiometric surveys followed by core drilling were carried out in western part of the complex. Rocks of carbonatite affinity have been intercepted in all the boreholes upto a maximum drilled depth of 150 m. It is for the first time that presence of carbonatite and carbonatite breccia has been reported below central basalt in the Amba Dongar complex. Continuity of carbonatites beyond the drilled depth is inferred. Petromineralogical and X-Ray Diffraction studies indicated presence of REE minerals such as monazite, thorite, cerite, synchisite and bastnasite. Besides, rare earth fluorocarbonates, parisite, florencite, barite, strontianite and columbite have also been reported by earlier investigators. Fairly good amount of pyrochlore (Nb mineral) is also present in all the variants of carbonatite. Detailed chemical analysis core at 1 m interval and of composite samples from every borehole was carried out. The results indicate homogeneity of mineralisation in the entire column upto an explored vertical depth of 120 m. Except a few lean zones, the entire column hosts REE mineralisation of the order of >1% ?REE. Some zones have indicated REE mineralisation of the order of >4 % also. Major element analysis of a composite sample representing a small block (400 m x 100 m x 113 m) indicates 14.69% SiO2, 10.57% Fe2O3, 7 21% MgO, 32.23% CaO, 2.77%, Al2O3, 1.48% P2O5, 2.13% MnO, 0.84% FeO, 0.37% TiO2, 0.95% Na2O, 1.35% K2O, and 23.50% LOI. 1.16% LREE (including 161 ppm HREE), 215 ppm Y, 650 ppm Nb, 310 ppm Th and 467 ppm V appear to be of economic significance. Additionally, presence of high content of Ba (2.65%), Sr (0.50%), Pb (530 ppm), F (1.95%) and Zn (1248 ppm) is also important. Taking into consideration these results, resource estimation of a small block of 400 m x 100 m (0.04 sq. km) with an average depth of 113 m was carried out Inferred REE resources ~140000 tonnes contained in 12.00 million tonne ore have been estimated with an average grade of 1.16% REE. Additionally, this block contains 9,600 tonnes Nb2O5 at an average grade of 0 08 % Nb2O5. These values indicate high potential of Amba Dongar carbonatite complex.
DS1990-1515
1990
Verma, R.K.Verma, R.K., Satyanarayana, Y.Gravity field, deep seismic sounding and crust -mantle structure over the Cuddapah basin and Dhawar Craton of IndiaTectonophysics, Vol. 178, No. 2-4, June 20, pp. 337-356IndiaGeophysics -seismics, Craton
DS1991-1795
1991
Verma, R.K.Verma, R.K.Geodynamics of Indian peninsula and the Indian plate marginA.a. Balkema, 375p. approx. $ 95.00IndiaGeodynamics, tectonics, Book -ad
DS1983-0616
1983
Verma, S.K.Verma, S.K.Tem Exploration for Diamonds Near Wajrakarur, A.p. IndiaThird Biennial Conference of The Australian Society of Exploration Geo, Oct. 31ST. TO Nov. 3RD. EXTENDED ABSTRACT VOLUME, PP. 73-75.India, Andhra PradeshKimberlite, Geophysics
DS2003-1424
2003
Verma, S.K.Verma, S.K.Geology, geophysics and geodynamics of extensive Proterozoic KCR volcanism in8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractIndiaDiamond exploration - geophysics, seismics, Tectonics
DS2003-1425
2003
Verma, S.K.Verma, S.K.Geophysical mapping of kimberlite pipes in south India8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractIndiaGeophysics
DS200412-2055
2003
Verma, S.K.Verma, S.K.Geophysical mapping of kimberlite pipes in south India.8 IKC Program, Session 8, POSTER abstractIndiaDiamond exploration Geophysics
DS200412-2056
2003
Verma, S.K.Verma, S.K.Geology, geophysics and geodynamics of extensive Proterozoic KCR volcanism in India.8 IKC Program, Session 8, AbstractIndiaDiamond exploration - geophysics, seismics Tectonics
DS200612-1478
2005
Verma, S.K.Verma, S.K.Diamond fertility and architecture of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 34-35.India, Andhra Pradesh, Dharwar CratonDiamond genesis
DS1991-1796
1991
Verma, S.P.Verma, S.P.Calderas: genesis, structure and unrestJournal of Volcanology and Geothermal Research, Vol. 47, No. 1-2, July pp. 1-205pItaly, Spain, Iberia, Canary Islands, MexicoCalderas, Structure
DS2000-0890
2000
Verma, S.P.Sheth, H.C., Torres-Alvarado, I.S., Verma, S.P.Beyond subduction and plumes: a unified tectonic petrogenetic model for the Mexican volcanic belt.International Geology Review, Vol.42,12,Dec. pp. 1116-32.MexicoSubduction - not specific to diamond
DS2002-1459
2002
Verma, S.P.Sheth, H.C., Torres Alvarado, I.S., Verma, S.P.What is the 'Calc alkaline rock series'?International Geology Review, Vol. 44, 8, pp. 686-701.GlobalAlkaline - classification
DS200412-0006
2004
Verma, S.P.Agrawal, S., Guevara, M., Verma, S.P.Discriminate analysis applied to establish major element field boundaries for tectonic varieties of basic rocks.International Geology Review, Vol. 46, 7, pp. 575-594.TechnologyGeochemistry - not specific to diamonds
DS200412-1898
2004
Verma, S.P.Srivastava, R.K., Singh, R.K., Verma, S.P.Neoarchean mafic volcanic rocks from the southern Bastar greenstone belt, central India: petrological and tectonic significance.Precambrian Research, Vol. 131, 3-4, pp. 305-322.IndiaTectonics - not specific to diamonds
DS1997-1207
1997
Vermaak, C.F.Vermaak, C.F.A brief overview of South Africa's mineral industry: world context and changing local circumstancesMineralium Deposita, Vol. 32, No. 4, pp. 312-322South AfricaMineral industry, reserves, dollar values, Economics, discoveries
DS200712-0095
2007
Vermaak, M.K.Boshoff, E.T., Morkel, J., Vermaak, M.K., Pistorius, P.C.Kimberlite degradation: the role of cation type.Minerals Engineering, Vol. 20, 15, pp. 1351-1359.TechnologyMining
DS200612-0946
2006
Vermaak, M.K.G.Morkel, J., Kruger, S.J., Vermaak, M.K.G.Characterization of clay mineral fractions in tuffisitic kimberlite breccias by x-ray diffraction.South African Institute of Mining and Metallurgy, Vol. 106, 6, pp. 397-406.Africa, South AfricaPetrology
DS200612-0947
2006
Vermaak, M.K.G.Morkel, J., Vermaak, M.K.G.The role of swelling clay in kimberlite weathering.Transactions of the Institution of Mining and Metallurgy, Vol. 115, 3, pp. 150-154.AfricaKimberlite weathering
DS200712-0752
2007
Vermaak, M.K.G.Morkel, J., Pistorius, P.C., Vermaak, M.K.G.Cation exchange behaviour of kimberlite in solutions containing CU2+ and K+.Minerals Engineering, Vol. 20, 12, October pp. 1145-1152.TechnologySmectites, ion exchange, reactions
DS1975-0885
1978
Vermeak, C.F.Vermeak, C.F.The Global Status of the South African Minerals Industry And Dat a Summaries of its Key Commodities.Geological Society of South Africa REV. PAPER., No. 1, SEPTEMBER 57P.South AfricaDiamonds
DS200412-1315
2004
Vermeer, M.Milne, G.A., Mitrovica, J.X., Scherneck, H.G., Davis, J.L., Johansson, J.M., Koivula, H., Vermeer, M.Continuous GPS measurements of Post glacial adjustment in Fennoscandia: 2. modeling results.Journal of Geophysical Research, Vol. 109, B2, 10.1029/2003 JB002619Europe, FennoscandiaGeophysics -
DS2002-1066
2002
Vermeersen, B.L.A.Mitrovica, J.X., Vermeersen, B.L.A.Ice sheets, sea level and the dynamic earthAmerican Geophysical Union, Geodynamics Series, Vol. 29, 310p.GlobalBook - Geomorphology - climatology
DS200412-1340
2002
Vermeersen, B.L.A.Mitrovica, J.X., Vermeersen, B.L.A.Ice sheets, sea level and the dynamic earth.American Geophysical Union, Geodynamics Series, Vol. 29, 310p.GlobalBook - geomorphology
DS1998-1537
1998
Vermeersen, L.L.A.Vermeersen, L.L.A., Sabadini, R., Bianco, G.Mantle viscosity inferences from joint inversions of Pleistocene deglaciation induced changes - geopotentialGeophs. Res. Lett., Vol. 25, No. 23, Dec. 1, pp. 4261-64.GlobalPolar wander - SIR analysis, Geomorphology
DS2002-1378
2002
Vermeersen, L.L.A.Sabadini, R., Marotta, A.M., De Franco, R., Vermeersen, L.L.A.Style of density stratification in the mantle and true polar wander induced by ice loadingJournal of Geophysical Research, Oct. 29, 10.1029/2001JB000889.MantleGeophysics - seismics
DS200512-1097
2005
Vermeersen, L.L.A.Tosi, N., Sabadini, R., Marotta, A.M., Vermeersen, L.L.A.Simultaneous inversion for the Earth's mantle viscosity and ice mass imbalance in Antarctica and Greenland.Journal of Geophysical Research, Vol. 110, B7, B07402 10.1029/2004 JB003236Europe, GreenlandMantle dynamics
DS2003-1426
2003
Vermeesch, P.Vermeesch, P.A second look at the geologic map of China: the Sloss approachInternational Geology Review, Vol. 45, 2, Feb. pp. 119-132.ChinaBlank
DS200412-2057
2003
Vermeesch, P.Vermeesch, P.A second look at the geologic map of China: the Sloss approach.International Geology Review, Vol. 45, 2, Feb. pp. 119-132.ChinaStratigraphy
DS201412-0274
2014
Vermeesch, P.Garzanti, E., Resentini, A., Ando, S., Vezzoli, G., Pereira, A., Vermeesch, P.Physical controls on sand and composition and relative durability of detrital minerals during ultra-long distance littoral and aeolian transport ( Namibia and southern Angola).Sedimentology, Vol. 62, 4, pp. 971-996.Africa, Namibia, AngolaDiamondiferous littoral deposits
DS201802-0238
2018
Vermeesch, P.Garzanti, E., Dinis, P., Vermeesch, P., Ando, S., Hahn, A., Huvi, J., Limonta, M., Padoan, M., Resentini, A., Rittner, M., Vezzoli, G.Sedimentary processes controlling ultralong cells of littoral transport: placer formation and termination of the Orange sand highway in southern Angola.Sedimentology, Vol. 65, 2, pp. 431-460.Africa, Angolaplacers, alluvials

Abstract: This study focuses on the causes, modalities and obstacles of sediment transfer in the longest cell of littoral sand drift documented on Earth so far. Sand derived from the Orange River is dragged by swell waves and persistent southerly winds to accumulate in four successive dunefields in coastal Namibia to Angola. All four dunefields are terminated by river valleys, where aeolian sand is flushed back to the ocean; and yet sediment transport continues at sea, tracing an 1800 km long submarine sand highway. Sand drift would extend northward to beyond the Congo if the shelf did not become progressively narrower in southern Angola, where drifting sand is funnelled towards oceanic depths via canyon heads connected to river mouths. Garnet-magnetite placers are widespread along this coastal stretch, indicating systematic loss of the low-density feldspatho-quartzose fraction to the deep ocean. More than half of Moçamedes Desert sand is derived from the Orange River, and the rest in similar proportions from the Cunene River and from the Swakop and other rivers draining the Damara Orogen in Namibia. The Orange fingerprint, characterized by basaltic rock fragments, clinopyroxene grains and bimodal zircon-age spectra with peaks at ca 0•5 Ga and ca 1•0 Ga, is lost abruptly at Namibe, and beach sands further north have abundant feldspar, amphibole-epidote suites and unimodal zircon-age spectra with a peak at ca 2•0 Ga, documenting local provenance from Palaeoproterozoic basement. Along with this oblique-rifted continental margin, beach placers are dominated by Fe-Ti-Cr oxides with more monazite than garnet and thus have a geochemical signature sharply different from beach placers found all the way along the Orange littoral cell. High-resolution mineralogical studies allow us to trace sediment dispersal over distances of thousands of kilometres, providing essential information for the correct reconstruction of ‘source to sink’ relationships in hydrocarbon exploration and to predict the long-term impact of man-made infrastructures on coastal sediment budgets.
DS201810-2387
2018
Vermeesch, P.Vermeesch, P.Statistical models for point counting data. ( heavy mineral analysis or micropalynology)Earth and Planetary Science Letters, Vol. 501, pp. 112-118.Globalstatistics

Abstract: Point-counting data are a mainstay of petrography, micropalaeontology and palynology. Conventional statistical analysis of such data is fraught with problems. Commonly used statistics such as the arithmetic mean and standard deviation may produce nonsensical results when applied to point-counting data. This paper makes the case that point-counts represent a distinct class of data that requires different treatment. Point-counts are affected by a combination of (1) true compositional variability and (2) multinomial counting uncertainties. The relative magnitude of these two sources of dispersion can be assessed by a chi-square statistic and test. For datasets that pass the chi-square test for homogeneity, the ‘pooled’ composition is shown to represent the optimal estimate for the underlying population. It is obtained by simply adding together the counts of all samples and normalising the resulting values to unity. However, more often than not, point-counting datasets fail the chi-square test. The overdispersion of such datasets can be captured by a random effects model that combines a logistic normal population with the usual multinomial counting uncertainties. This gives rise to the concept of a ‘central’ composition as a more appropriate way to average overdispersed data. Two-or three-component datasets can be displayed on radial plots and ternary diagrams, respectively. Higher dimensional datasets may be visualised and interpreted by Correspondence Analysis (CA). This is a multivariate ordination technique that is similar in purpose to Principal Component Analysis (PCA). CA and PCA are both shown to be special cases of Multidimensional Scaling (MDS). Generalising this insight to multiple datasets allows point-counting data to be combined with other data types such as chemical compositions by means of 3-way MDS. All the techniques introduced in this paper have been implemented in theprovenanceR-package, which is available from http://provenance .london -geochron .com.
DS202106-0937
2021
Vermeulen, D.Gomez-Arias, A., Yesares, L., Carabello, M.A., Maleke, M., Vermeulen, D., Nieto, J.M., van Heerden, E., Castillo, J.Environmental and geochemical characterization of alkaline mine wastes from Phalaborwa ( Palabora) complex, South Africa.Journal of Geochemical Exploration, Vol. 224, 106757, 13p. PdfAfrica, South Africadeposit - Palabora

Abstract: A detailed characterization of alkaline tailing ponds and waste rock dumps from Phalaborwa Igneous Complex (PIC) South Africa, has been accomplished. The study goes beyond the environmental characterization of mining wastes, offering the first insight towards the recycling of the wastes as alkaline reagent to neutralize acid industrial wastewater. To achieve these aims, tailings and waste rocks were characterized using a combination of conventional, novel and modified Acid Rock Drainage (ARD) prediction methodologies, as well as South African leachate tests, sequential extractions and pseudo-total digestions. The scarcity of Fe-sulphide minerals and the abundance of alkaline minerals indicated that PIC wastes are not ARD producers. The highest neutralization potential was found in the carbonatite rocks and East tailing samples (range between 289 and 801 kg CaCO3 eq/t). According to the National Environmental Management Waste Act (59/2008) of South Africa, tailing ponds and waste rock dumps from PIC classify as non-hazardous (Type 3 waste). The sequential extractions showed that the different fractions from most of the samples would mostly release sulphate and non-toxic elements, such as Ca, Mg, Na and K, which might be a concern if leached in high concentration. In addition, relatively high concentrations of radionuclides, such as U and Th (average of 6.7 and 36.3 mg/kg, respectively) are present in the non-labile fraction of PIC wastes, while the leachable concentrations were always below 0.006 mg/L. Among PIC wastes, East tailing would be the best option as alkaline reagent to neutralize acid wastewater because of its high neutralization potential and non-harmful leachate composition. In general, this study exposes the shortcomings in mine waste characterization, particularly for alkaline mine wastes, and introduces the assessment of potential revalorization as a novel practice in mine waste characterization that, if extended as a regular practice, would facilitate a circular economy approach to the mining industry with its consequent economic and environmental benefits.
DS2002-1661
2002
Vermote, E.F.Vermote, E.F., Roy, D.P.Land surface hot spot observed by MODIS over central AfricaInternational Journal of Remote Sensing, Vol.23,1,pp.2141-44., Vol.23,1,pp.2141-44.Africa, Central African RepublicRemote sensing, Plume
DS2002-1662
2002
Vermote, E.F.Vermote, E.F., Roy, D.P.Land surface hot spot observed by MODIS over central AfricaInternational Journal of Remote Sensing, Vol.23,1,pp.2141-44., Vol.23,1,pp.2141-44.Africa, Central African RepublicRemote sensing, Plume
DS1986-0832
1986
Vernadskiy, V.I.Vernadskiy, V.I.Some proofs of the reality of cavitational synthesis of diamonds in nature #1 (Galimov)Geochemistry International, Vol. 22, No. 7, pp. 99-113RussiaDiamond morphology
DS200612-0385
2006
Vernant, P.Fadil, A., Vernant, P., McClusky, S., Reilinger, R., Gomez, F., Ben Sari, D., Mourabit, Feigl, BarazangiActive tectonics of the western Mediterranean: geodetic evidence for rollback of a delaminated subcontinental lithospheric slab beneath the Rif Mountains, Morocco.Geology, Vol. 34, 7, July pp. 529-532.Africa, MoroccoTectonics, continental dynamics
DS200612-1150
2006
Vernant, P.Reilinger, R., McClusky, S., Vernant, P., Lawrence, S., Ergintav, Cakmak, Ozener, Kadirov, Guliev, StepanyanGPS constraints on continental deformation in the Africa Arabia Eurasia continental collision zone and implications for the dynamics of plate interactions.Journal of Geophysical Research, Vol. 111,B5 B05411.AfricaGeodynamics
DS200612-1155
2006
Vernant, P.Relinger, R., McClusky, S., Vernant, P., Lawrence, S.GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of plate interactions.Journal of Geophysical Research, Vol. 111, B5, May 31, B05411AfricaTectonics
DS1860-0480
1885
Verne, J.Verne, J.The Southern Star or the Diamond LandNew York: G. Munro, 37P.Africa, South AfricaTravelogue
DS1998-1538
1998
Vernet, D.Vernet, D., Dufresne, M.B.Metallic and industrial mineral assessment report on the Pelican Mountain area, Alberta.Alberta Geological Survey, MIN 19980009AlbertaExploration - assessment, Ellesmere Minerals Limited
DS1995-1250
1995
Vernhet, Y et al.Milesi, J-P, Egal, E., Ledru, P., Vernhet, Y et al.Les mineralisations du Nord de la Guyana francaise dans leur cadregeologique.Chron. Recherche Min., No. 518, pp. 5-58.French GuianaGeology -3 p. english summary general geology, Metallogeny - mainly gold related
DS2001-0251
2001
VerniaDi Battistini, G., Montanini, Vernia, VenturelleiPetrology of melilite bearing rocks from Montefiascone volcanic complex: new insights ultrapotassic volcanicsLithos, Vol. 59, No.1-2, Oct. pp. 109-25.ItalyUltrapotassic
DS2001-0253
2001
VerniaDiBattistini, G., Montanini, Vernia, Venturelli, TonariPetrology of melilite bearing rocks from the Montefiascone volcanic complex Roman magmatic provinceLithos, Vol. 59, No. 1-2, Oct. pp. 1-24.ItalyUltrapotassic volcanism
DS1990-0218
1990
Vernieres, J.Bodinier, J.L., Vasseur, G., Vernieres, J., Dupuy, C., Fabries, J.Mechanisms of mantle metasomatism: geochemical evidence from the Lherzorogenic peridotiteJournal of Petrology, Vol. 31, No. 3, June pp. 597-628GermanyMantle Metasomatism, Geochemistry
DS200712-0840
2006
Verniers, J.Pharaoh, T.C., Winchester, J.A., Verniers, J., Lassen, A., Seghedi, A.The Western accretionary margin of the East European Craton: an overview.Geological Society of London Memoir, No. 32, pp. 291-312.Russia, Europe, UralsCraton
DS200612-0912
2005
Vernikovksy, V.A.Metelkin, D.V., Vernikovksy, V.A., Lazanskii, A.Yu., Belonos, I.V.The Siberian Craton in the structure of the supercontinent Rodinia: analysis of paleomagnetic data.Doklady Earth Sciences, Vol. 404, 7, pp. 1021-1026.RussiaTectonics, geophysics - paleomagnetism
DS200812-1209
2008
Vernikovskaya, A.A.E.A.Vernikovsky, V.A.A., Vernikovskaya, A.A.E.A., Salanikova, E.A.B.A., Berezhnaya, Larionov, Kotov, KovachLate Riphean alkaline magmatism in the western margin of the Siberian craton: a result of continental rifting or accretionary events?Doklady Earth Sciences, Vol. 419, 2, pp. 226-230.RussiaMagmatism
DS201312-0751
2012
Vernikovskaya, A.E.Romanova, I.V., Vernikovskaya, A.E., Vernikovsky, V.A., Matushkin, N.Yu., Larionov, A.N.Neoproterozoic alkaline magmatism and associated igneous rocks in the western framing of the Siberian craton: petrography, geochemistry, and geochronology.Russian Geology and Geophysics, Vol. 53, 11, pp. 1176-1196.RussiaMagmatism
DS200712-1117
2007
Vernikovskaya, I.V.Vernikovskaya, I.V., Salnikova, Matushkin, YasnevThe Neoproterozoic alkaline rocks of the Yenisey Ridge, western margin of the Siberian Craton: mineralogy, geochemistry and geochronology.Plates, Plumes, and Paradigms, 1p. abstract p. A1065.RussiaIjolite
DS2001-0262
2001
Vernikovsky, V.A.Dobretsov, N.L., Vernikovsky, V.A.Mantle plumes and their geologic manifestationsInternational Geology Review, Vol. 43, No. 9, Sept. pp. 771-87.MantlePlumes, hot spots, Review
DS200512-0721
2004
Vernikovsky, V.A.Metelkin, D.V., Vernikovsky, V.A., Kazansky, A.Y., Bogolepova, O.K., Gubanov, A.P.Paleozoic history of the Kara microcontinent and its relation to Siberia and Baltica: paleomagnetism, paleogeography and tectonics.Tectonophysics, Vol. 398, 3-4, April 13, pp. 225-243.Russia, Siberia, Baltic ShieldTectonics
DS200712-0713
2007
Vernikovsky, V.A.Melekin, D.V., Vernikovsky, V.A., KKKKazansky, A.Yu.Neoproterozoic evolution of Rodinia: constraints from new paleomagnetic dat a on the western margin of the Siberian Craton.Russian Geology and Geophysics, Vol. 48, pp. 32-45.RussiaPaleomagnetism
DS201312-0751
2012
Vernikovsky, V.A.Romanova, I.V., Vernikovskaya, A.E., Vernikovsky, V.A., Matushkin, N.Yu., Larionov, A.N.Neoproterozoic alkaline magmatism and associated igneous rocks in the western framing of the Siberian craton: petrography, geochemistry, and geochronology.Russian Geology and Geophysics, Vol. 53, 11, pp. 1176-1196.RussiaMagmatism
DS200812-1209
2008
Vernikovsky, V.A.A.Vernikovsky, V.A.A., Vernikovskaya, A.A.E.A., Salanikova, E.A.B.A., Berezhnaya, Larionov, Kotov, KovachLate Riphean alkaline magmatism in the western margin of the Siberian craton: a result of continental rifting or accretionary events?Doklady Earth Sciences, Vol. 419, 2, pp. 226-230.RussiaMagmatism
DS1991-0282
1991
Vernon, R.H.Collins, W.J., Vernon, R.H., Clarke, G.L.Discrete Proterozoic structural terranes associated with low pressure, high Tmetamorphism, Anmatjira Range, Arunta Inlier, central Australia: tectonicimplicationsJournal of Structural Geology, Vol. 13, No. 10, pp. 1157-1171AustraliaProterozoic, Tectonics, Structure
DS1993-0275
1993
Vernon, R.H.Collins, W.J., Vernon, R.H.Granulite facies metamorphism in the lower crust: the Mt Hay-Mt. Chappleexample, Arunta inlier, central Australia.The Xenolith window into the lower crust, abstract volume and workshop, p. 5.AustraliaXenoliths
DS1993-1660
1993
Vernon, R.H.Vernon, R.H., Collins, W.J., Paterson, S.R.Pre-foliation metamorphism in low-pressure/high temperature terrainsTectonophysics, Vol. 219, pp. 241-256Australia, CaliforniaTectonics, structure, Metamorphism heat source
DS1994-0329
1994
Vernon, R.H.Collins, W.J., Vernon, R.H.A rift drift delamination model of continental evolution: Paleozoic tectonic developmentTectonophysics, Vol. 235, pp. 249-275Australia, Eastern AustraliaTectonics, Gondwanaland
DS1995-1447
1995
Vernon, R.H.Paterson, S.R., Vernon, R.H.Bursting the bubble of ballooning plutons: a return to nested diapir semplaced by multiple processesGeological Society of America (GSA) Bulletin, Vol. 107, No. 11, Nov. pp. 1356-1380Ireland, Australia, CaliforniaMagma chamber, Models -Ardara, Cannibal Creek, Papoose Flat
DS200812-0490
2008
Veronneau, M.Huang, J., Veronneau, M., Mainville, A.Assessment of systematic errors in the surface gravity anomalies over North America using the GRACE gravity model.Geophysical Journal International, Vol. 175, 1, pp. 46-54.United States, CanadaGeophysics - gravity
DS1995-1984
1995
Verosub, K.L.Verosub, K.L., Roberts, A.P.Environmental magnetism: past, present and futureJournal of Geophysical Research, Vol. 100, No. B2, Feb. 10, pp. 2175-2192GlobalMagnetism -environmental, Review
DS1998-1539
1998
Verpaelst, P.Verpaelst, P., Perreault, S., Brisebois, D., BoudriasGeologie de la region de la riviere Koroc, Grand NordQuebec Department of Mines, DV 98-05, p. 35.QuebecGeology
DS201312-0083
2013
Verplanck, P.Blessington, M., Kettler, R., Verplanck, P., Farmer, G.L.Niobium mineralization in a magnetite rich carbonatite, Elk Creek Nebraska, USA.Goldschmidt 2013, AbstractUnited States, NebraskaCarbonatite
DS1995-1985
1995
Verplanck, P.L.Verplanck, P.L., Farmer, G.L., Snee, L.W.Isotopic evidence on the origin of compositional layering in an epizonal magma bodyEarth and Planetary Science Letters, Vol. 136, No. 1-2, Nov. 1, pp. 31-42GlobalLayered intrusions, Geochronology
DS201512-1982
2015
Verplanck, P.L.Verplanck, P.L., Farmer, G.L., Mariano, A.N.Nd and Sr isotopic composition of rare earth element mineralized carbonatites.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 65-74.GlobalCarbonatite

Abstract: For nearly 50 years, carbonatites have been the primary sources of niobium and rare earth elements (REEs), particularly the light REEs including La, Ce, Pr, and Nd. In addition, carbonatites may be enriched in other critical elements and have the potential to be future sources. Currently, only fi ve of the more than 500 known carbonatites in the world are being mined for REEs: Bayan Obo (Inner Mongolia, China); Maoniuping (Sichuan, China); Dalucao (or Daluxiang, Sichuan, China); and Mountain Pass (California, USA), and the carbonatite-derived laterite at Mount Weld (Australia). To achieve ore-grade REE enrichment, initial carbonatitic magmas require an adequate endowment of REEs and need to evolve in ways for these elements to concentrate in REE-bearing mineral phases. Radiogenic isotope studies of carbonatites clearly point to a mantle origin, but a wide range in isotopic compositions has led to contrasting views about the specifi c mantle reservoir(s) that sourced carbonatites. In this study we use the neodymium and strontium isotopic compositions of a suite of mineralized carbonatites to establish the nature of the source magmas. We examine samples that span a wide range in age (~23 Ma to 1385 Ma), Nd concentrations (3720 to 32,900 ppm), and Sr concentrations (2290 to 167,900 ppm). Our Nd and Sr isotopic data include multiple samples from Mountain Pass (USA; ?Nd i = -3.1 to -5.4, Sri = 0.70512 to 0.70594), Elk Creek (USA; ~?Nd i = 1.7, Sri = 0.7035), and Maoniuping (China; ?Nd i = -4.1 and -4.2, Sri = 0.70627 and 0.70645), and one sample each from Bear Lodge (USA; ?Nd i = 0.1, Sri = 0.70441), Kangankunde (Malawi; ?Nd i = 3.3, Sri = 0.70310), Adiounedj (Mali; ?Nd i = -0.1, Sri = 0.70558), and Mushgai Khudag (Mongolia; ?Nd i = -1.3, Sri = 0.70636). Isotopic data from two producing carbonatite REE deposits (Mountain Pass and Maoniuping) have broadly similar isotopic compositions (?Nd i = -3.1 to -5.4 and Sri = 0.7051 to 0.7065), and these compositions point to a carbonated source in the lithospheric mantle. Mineralized but unmined carbonatites have higher Nd initial isotopic compositions (?Nd i = -1.3 to 3.3) and a wider range in Sr isotopic compositions (Sri = 0.70310 to 0.70637), but these data are consistent with a lithospheric mantle reservoir.
DS201605-0915
2016
Verplanck, P.L.Verplanck, P.L., Hitzman, M.W.Rare earth and critical elements in ore deposits.SEG Reviews in Economic Geology, editors Verplanck, P.L., Hitzman, M.W., No. 18, pp. 1-4.TechnologyRare earths
DS201605-0916
2016
Verplanck, P.L.Verplanck, P.L., Mariano, A.N., Mariano, A.M.Jr.Rare earth element ore geology of carbonatites.SEG Reviews in Economic Geology, editors Verplanck, P.L., Hitzman, M.W., No. 18, pp. 5-32.China, United States, CaliforniaBauan Obo, Maoniuping, Dalucao, Mountain Pass
DS201702-0248
2016
Verplanck, P.L.Verplanck, P.L., Hitzman, M.W.Rare earth and critical elements in ore deposits.Reviews in Economic Geology, Vol. 18, 365p. $ 72. CD/pdf/printGlobalBook - rare earth

Abstract: This special volume provides a comprehensive review of the current state of knowledge for rare earth and critical elements in ore deposits. The first six chapters are devoted to rare earth elements (REEs) because of the unprecedented interest in these elements during the past several years. The following eight chapters describe critical elements in a number of important ore deposit types. These chapters include a description of the deposit type, major deposits, critical element mineralogy and geochemistry, processes controlling ore-grade enrichment, and exploration guides. This volume represents an important contribution to our understanding of where, how, and why individual critical elements occur and should be of use to both geoscientists and public policy analysts.
DS201702-0249
2016
Verplanck, P.L.Verplanck, P.L., Mariano, A.N., Mariano, A. Jr.Rare earth element ore geology of carbonatites.Reviews in Economic Geology, Vol. 18, pp. 5-32.GlobalCarbonatite
DS201811-2618
2019
Verplanck, P.L.Xie, Y., Qu, Y., Zhong, R., Verplanck, P.L., Meffre, S., Xu, D.The ~1.85 Ga carbonatite in north China and its implications on the evolution of the Columbia supercontinent.Gondwana Research, Vol. 65, pp. 125-141.Chinacarbonatite

Abstract: Mantle-derived carbonatites provide a unique window in the understanding of mantle characteristics and dynamics, as well as insight into the assembly and breakup of supercontinents. As a petrological indicator of extensional tectonic regimes, Archean/Proterozoic carbonatites provide important constraints on the timing of the breakup of ancient supercontinents. The majority of the carbonatites reported worldwide are Phanerozoic, in part because of the difficulty in recognizing Archean/Proterozoic carbonatites, which are characterized by strong foliation and recrystallization, and share broad petrologic similarities with metamorphosed sedimentary lithologies. Here, we report the recognition of a ~1.85?Ga carbonatite in Chaihulanzi area of Chifeng in north China based on systematic geological, petrological, geochemical, and baddeleyite U-Pb geochronological results. The carbonatite occurs as dikes or sills emplaced in Archean metasedimentary rocks and underwent intense deformation. Petrological and SEM/EDS results show that calcite and dolomite are the dominant carbonate minerals along with minor and varied amounts of Mg-rich mafic minerals, including forsterite (with Fo?>?98), phlogopite, diopside, and an accessory amount of apatite, baddeleyite, spinel, monazite, and ilmenite. The relatively high silica content together with the non-arc and OIB-like trace element signatures of the carbonatite indicates a hot mantle plume as the likely magma source. The depleted Nd isotopic signatures suggest that plume upwelling might be triggered by the accumulation of recycled crust in the deep mantle. As a part of the global-scale Columbia supercontinent, the Proterozoic tectonic evolution of the North China Craton (NCC) provides important insights into the geodynamics governing amalgamation and fragmentation of the supercontinent. The Paleo-Mesoproterozoic boundary is the key point of tectonic transition from compressional to extensional settings in the NCC. The newly identified ~1.85?Ga carbonatite provides a direct link between the long-lasting supercontinental breakup and plume activity, which might be sourced from the “slab graveyard,” continental crustal slabs subducted into asthenosphere, beneath the supercontinent. The carbonatite provides a precise constraint of the initiation of the continental breakup at ~1.85?Ga.
DS201812-2900
2019
Verplanck, P.L.Xie, Y., Qu, Y., Zhong, R., Verplanck, P.L., Meffre, S., Xu, D.The ~1/85 carbonatite in north China and its implications on the evolution of the Columbia supercontinent.Gondwana Research, Vol. 65, pp. 125-141.Chinacarbonatite

Abstract: Mantle-derived carbonatites provide a unique window in the understanding of mantle characteristics and dynamics, as well as insight into the assembly and breakup of supercontinents. As a petrological indicator of extensional tectonic regimes, Precambrian carbonatites provide important constraints on the timing of the breakup of ancient supercontinents. The majority of the carbonatites reported worldwide are Phanerozoic, in part because of the difficulty in recognizing Precambrian carbonatites, which are characterized by strong foliation and recrystallization, and share broad petrologic similarities with metamorphosed sedimentary lithologies. Here we report the recognition of a ~1.85?Ga carbonatite in Chaihulanzi area of Chifeng in north China based on systematic geological, petrological, geochemical, and baddeleyite U-Pb geochronological results. The carbonatite occurs as dikes or sills emplaced in Archean metasedimentary rocks and underwent intense deformation. Petrological and SEM/EDS results show that calcite and dolomite are the dominant carbonate minerals along with minor and varied amounts of Mg-rich mafic minerals, including forsterite (with Fo?>?98), phlogopite, diopside, and an accessory amount of apatite, baddeleyite, spinel, monazite, and ilmenite. The relatively high silica content together with the non-arc and OIB-like trace element signatures of the carbonatite indicates a hot mantle plume as the likely magma source. The depleted Nd isotopic signatures suggest that plume upwelling might be triggered by the accumulation of recycled crust in the deep mantle. As a part of the global-scale Columbia supercontinent, the Proteozoic tectonic evolution of the North China Craton (NCC) provides important insights into the geodynamics governing amalgamation and fragmentation of the supercontinent. The Paleo-Mesoproterozoic boundary is the key point of tectonic transition from compressional to extensional settings in the NCC. The newly-identified ~1.85?Ga carbonatite provides a direct link between the long-lasting supercontinental breakup and plume activity, which might be sourced from the “slab graveyard”, continental crustal slabs subducted into asthenosphere, beneath the supercontinent. The carbonatite provides a precise constraint of the initiation of the continental breakup at ~1.85?Ga.
DS201901-0092
2018
Verplanck, P.L.Xie, Y., Qu, Y., Zhong, R., Verplanck, P.L., Meffre, S., Xu, D.The ~1.85 GA carbonatite in north China and its implications on the evolution of the Columbia supercontinent. Chaitulanzi, ChifengGondwana Research, Vol. 65, pp. 135-141.Chinacarbonatite

Abstract: Mantle-derived carbonatites provide a unique window in the understanding of mantle characteristics and dynamics, as well as insight into the assembly and breakup of supercontinents. As a petrological indicator of extensional tectonic regimes, Precambrian carbonatites provide important constraints on the timing of the breakup of ancient supercontinents. The majority of the carbonatites reported worldwide are Phanerozoic, in part because of the difficulty in recognizing Precambrian carbonatites, which are characterized by strong foliation and recrystallization, and share broad petrologic similarities with metamorphosed sedimentary lithologies. Here we report the recognition of a ~1.85?Ga carbonatite in Chaihulanzi area of Chifeng in north China based on systematic geological, petrological, geochemical, and baddeleyite U-Pb geochronological results. The carbonatite occurs as dikes or sills emplaced in Archean metasedimentary rocks and underwent intense deformation. Petrological and SEM/EDS results show that calcite and dolomite are the dominant carbonate minerals along with minor and varied amounts of Mg-rich mafic minerals, including forsterite (with Fo?>?98), phlogopite, diopside, and an accessory amount of apatite, baddeleyite, spinel, monazite, and ilmenite. The relatively high silica content together with the non-arc and OIB-like trace element signatures of the carbonatite indicates a hot mantle plume as the likely magma source. The depleted Nd isotopic signatures suggest that plume upwelling might be triggered by the accumulation of recycled crust in the deep mantle. As a part of the global-scale Columbia supercontinent, the Proteozoic tectonic evolution of the North China Craton (NCC) provides important insights into the geodynamics governing amalgamation and fragmentation of the supercontinent. The Paleo-Mesoproterozoic boundary is the key point of tectonic transition from compressional to extensional settings in the NCC. The newly-identified ~1.85?Ga carbonatite provides a direct link between the long-lasting supercontinental breakup and plume activity, which might be sourced from the “slab graveyard”, continental crustal slabs subducted into asthenosphere, beneath the supercontinent. The carbonatite provides a precise constraint of the initiation of the continental breakup at ~1.85?Ga.
DS202006-0958
2019
Verplanck, P.L.Xie, Y., Verplanck, P.L., Hou, Z., Zhong, R.Rare Earth element deposits in China: a review and new understandings.SEG Special Publication , No. 22, pp. 500-552.ChinaREE

Abstract: The rare earth elements (REEs) consist of the 15 lantha-nide elements (La to Lu). Because of the increasing application of REEs and yttrium (REY) in high-and green-tech industries, the demand for the REY is projected to increase in the future. Rare earth elements are relatively abundant in the Earth's crust, but discovered, minable concentrations are less common than for most other ore types. Bastnaesite and monazite are the main mineral source of REEs in the world. Bastnaesite-hosted deposits in China and the United States Abstract China has been the world's leading rare earth element (REE) and yttrium producer for more than 20 years and hosts a variety of deposit types. Carbonatite-related REE deposits are the most significant REE deposit type, with REY (REE and yttrium)-bearing clay deposits, or ion adsorption-type deposits, being the primary source of the world's heavy REEs. Other REY resources in China include those hosted in placers, alkaline granites, pegmatites, and hydrothermal veins, as well as in additional deposit types in which REEs may be recovered as by-product commodities. Carbonatite-related REE deposits in China provide nearly all the light REE production in the world. Two giant deposits are currently being mined in China: Bayan Obo and Maoniuping. The carbonatite-related REE deposits in China occur along the margins of Archean-Paleoproterozoic blocks, including the northern , southern, and eastern margins of the North China craton, and the western margin of the Yangtze craton. The carbonatites were emplaced in continental rifts (e.g., Bayan Obo) or translithospheric strike-slip faults (e.g., Maoniuping) along reactivated craton margins. The craton margins provide the first-order control for carbonatite-related REE resources. Four REE metallogenic belts, including the Proterozoic Langshan-Bayan Obo, late Paleozoic-early Mesozoic eastern Qinling-Dabie, late Mesozoic Chishan-Laiwu-Zibo, and Cenozoic Mianning-Dechang belts, occur along cratonic margins. Geologic and geochemical data demonstrate that the carbonatites in these belts originated from mantle sources that had been previously enriched, most likely by recycled marine sediments through subduction zones during the assembly of continental blocks. Although the generation of carbonatite magma is debated, a plausible mechanism is by liquid immiscibility between silicate and carbonate melts. This process would further enrich REEs in the carbonatite end member during the evolution of mantle-derived magma. The emplacement of carbonatite magma in the upper crust, channeled by translithospheric faults in extensional environments, leads to a rapid decompression of the magma and consequently exsolution of a hydrothermal fluid phase. The fluid is characterized by high temperature (600°-850°C), high pressure (up to 350 MPa), and enrichment in sulfate, CO2, K, Na, Ca, Sr, Ba, and REEs. Immiscibility of sulfate melts from the aqueous fluid, and phase separation between CO2 and water may take place upon fluid cooling. Although both sulfate and chloride have been called upon as important ligands in hydrothermal REE transport, results of our studies suggest that sulfate is more important. The exsolution of a sulfate melt from the primary carbonatite fluid would lead to a significant decrease of the sulfate activity in the fluid and trigger REE precipitation. The subsequent unmixing between CO2 and water may also play an important role in REE precipitation. Because of the substantial ability of the primary carbonatite fluid to contain REEs, a large-volume magma chamber or huge fluid flux are not necessary for the formation of a giant REE deposit. A dense carbonatite fluid and rapid evolution hinder long distance fluid transportation and distal mineralization. Thus, carbonatite-related alteration and mineralization occur in or proximal to carbonatite dikes and sills, and this is observed in all carbonatite-related REE deposits in China. Ion adsorption-type REE deposits are primarily located in the South China block and are genetically linked to the weathering of granite and, less commonly, volcanic rocks and lamprophyres. Indosinian (early Mesozoic) and Yanshanian (late Mesozoic) granites are the most important parent rocks for these REE deposits. Hydro-thermal alteration by fluids exsolved from late Mesozoic granites or related alkaline rocks (e.g., syenite) may have enriched the parent rocks in REEs, particularly the heavy REEs. Furthermore, this alteration process led to the transformation of some primary REE minerals to secondary REE minerals that are more readily broken down during subsequent weathering. During the weathering process, the REEs are released from parent rocks and adsorbed onto kaolinite and halloysite in the weathering profile, and further enriched by the loss of other material to form the ion adsorption-type REE deposits. A warm and humid climate and a low-relief landscape are important characteristics for development of ion adsorption REE deposits.
DS201412-0947
2014
Verplank, P.L.Verplank, P.L., Kettler, R.M., Blessington, M.J., Lowers, H.A., Koenig, A.E., Farmer, G.L.Rare earth element and niobium enrichments in the Elk Creek carbonatite, USA.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, http://alkaline2014.comUnited States, NebraskaCarbonatite
DS202011-2069
2019
Verplank, P.L.Xie, Y., Verplank, P.L., Hou, Z., Zhong, R.IN: An overview of mineral deposits of China. Rare earth element deposits in China.SEG Special Publication, No. 22, pp. 509-552.ChinaREE

Abstract: China is the world’s leading rare earth element (REE) producer and hosts a variety of deposit types. Carbonatite- related REE deposits, the most significant deposit type, include two giant deposits presently being mined in China, Bayan Obo and Maoniuping, the first and third largest deposits of this type in the world, respectively. The carbonatite-related deposits host the majority of China’s REE resource and are the primary supplier of the world’s light REE. The REE-bearing clay deposits, or ion adsorption-type deposits, are second in importance and are the main source in China for heavy REE resources. Other REE resources include those within monazite or xenotime placers, beach placers, alkaline granites, pegmatites, and hydrothermal veins, as well as some additional deposit types in which REE are recovered as by-products. Carbonatite-related REE deposits in China occur along craton margins, both in rifts (e.g., Bayan Obo) and in reactivated transpressional margins (e.g., Maoniuping). They comprise those along the northern, eastern, and southern margins of the North China block, and along the western margin of the Yangtze block. Major structural features along the craton margins provide first-order controls for REE-related Proterozoic to Cenozoic carbonatite alkaline complexes; these are emplaced in continental margin rifts or strike-slip faults. The ion adsorption-type REE deposits, mainly situated in the South China block, are genetically linked to the weathering of granite and, less commonly, volcanic rocks and lamprophyres. Indosinian (early Mesozoic) and Yanshanian (late Mesozoic) granites are the most important parent rocks for these REE deposits, although Caledonian (early Paleozoic) granites are also of local importance. The primary REE enrichment is hosted in various mineral phases in the igneous rocks and, during the weathering process, the REE are released and adsorbed by clay minerals in the weathering profile. Currently, these REE-rich clays are primarily mined from open-pit operations in southern China. The complex geologic evolution of China’s Precambrian blocks, particularly the long-term subduction of ocean crust below the North and South China blocks, enabled recycling of REE-rich pelagic sediments into mantle lithosphere. This resulted in the REE-enriched nature of the mantle below the Precambrian cratons, which were reactivated and thus essentially decratonized during various tectonic episodes throughout the Proterozoic and Phanerozoic. Deep fault zones within and along the edges of the blocks, including continental rifts and strike-slip faults, provided pathways for upwelling of mantle material.
DS201412-0209
2014
Verrall, M.Downes, P.J., Demeny, A., Czuppon, G., Jacques, A.L., Verrall, M., Sweetapple, M., Adams, D., McNaughton, N.J., Gwalani, L.G., Griffin, B.J.Stable H-C-O isotope and trace element geochemistry of the Cummins Range carbonatite complex, Kimberley region Western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions.Mineralium Deposita, in press available 28p.AustraliaCarbonatite
DS201412-0210
2014
Verrall, M.Downes, P.J., Demeny, A., Czuppon, G., Jaques, A.L., Verrall, M., Sweetapple, M., Adams, D., McNaughton, N.J., Gwalani, L.G., Griffin, B.J.Stable H-C-O isotope and trace element geochemistry of the Cummins Range carbonatite complex, Kimberley region western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions.Mineralium Deposita, Vol. 49, p. 905-932.AustraliaCarbonatite
DS2003-1408
2003
Verran, D.Van Coller, B., Hildenbrand, P., Verran, D., Barnes, F., Nowicki, T.E.Southern African case studies of variations in indicator mineral characteristics with8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractSouth AfricaBlank
DS200412-2034
2003
Verran, D.Van Coller, B., Hildenbrand, P., Verran, D., Barnes, F., Nowicki, T.E., Baumgartner, M., Ott, L., Gurney, J.J.Southern African case studies of variations in indicator mineral characteristics with distance from kimberlite source.8 IKC Program, Session 8, POSTER abstractAfrica, South AfricaDiamond exploration
DS202006-0939
2020
Verrier, F.Moulin, M., Aslainian, D., Evain, M., Lepetre, A., Schnurle, P., Verrier, F., Thompson, J., De Clarens, P., Leroy, S., Dias, N.Gondwana breakup: messages from the north Natal Valley.Terra Nova, Vol. 32, 3, pp. 205-210.Africa, Mozambiquegeophysics - seismics

Abstract: The Natal Valley, offshore Mozambique, is a key area for understanding the evolution of East Gondwana. Within the scope of the integrated multidisciplinary PAMELA project, we present new wide?angle seismic data and interpretations, which considerably alter Geoscience paradigms. These data reveal the presence of a 30?km?thick crust that we argue to be of continental nature. This falsifies all the most recent palaeo?reconstructions of the Gondwana. This 30?km?thick continental crust 1,000 m below sea level implies a complex history with probable intrusions of mantle?derived melts in the lower crust, connected to several occurrences of magmatism, which seems to evidence the crucial role of the lower continental crust in passive margin genesis.
DS202202-0223
2021
Verrier, F.Watremez, L., Leroy, S., d'Acremont, E., Roche, V., Evain, M., Lepretre, A., Verrier, F., Aslanian, D., Dias, N., Afilhado, A., Schnurle, P., Castilla, R., Despinois, F., Moulin, M. The Limpopo magma-rich transform margin, south Mozambique - pt. 1 Insights from deep-structure seismic imaging.Tectonics, e2021TC006915Africa, Mozambiquegeophysics -seismics

Abstract: A variety of structures results from the interplay of evolving far-field forces, plate kinematics, and magmatic activity during continental break-up. The east Limpopo transform margin, offshore northern Mozambique, formed as Africa and Antarctica separated during the mid-Jurassic period break-up of the Gondwana supercontinent. The nature of the crust onshore has been discussed for decades in an effort to resolve issues with plate kinematic models. Two seismic refraction profiles with coincident multichannel seismic reflection profiles allow us to interpret the seismic velocity structures across the margin, both onshore and offshore. These seismic profiles allow us to (a) delineate the major regional crustal domains; (b) identify widespread indications of magmatic activity; and (c) map crustal structure and geometry of this magma-rich transform margin. Careful examination of the profiles allows us to make the following observations and interpretations: (a) on land, continental crust is overlain by a >10-km thick volcano-sedimentary wedge related to an early rifting stage, (b) offshore, thick oceanic crust formed due to intense magmatic activity, and between the two (c) a 50-60-km wide transform zone where the crustal structures are affected by intense magmatic activity and faulting. The prominent presence of intrusive and extrusive igneous units may be attributed to the combination of a deep-seated melting anomaly and a trans-tensional fault zone running through thinned lithosphere that allowed melt to reach the surface. A comparison of the crustal thinning along other transform margins shows a probable dependence with the thermal and/or tectonic history of the lithosphere.
DS1975-0646
1977
Versfeld, J.A.Versfeld, J.A.The Geology of a Portion of the Wesselton Kimberlite PipeBsc. Hons. Thesis University Cape Town., South AfricaMineralogy, Petrology
DS1989-1633
1989
Versfeld, J.A.Wilson, A.H., Versfeld, J.A., Hunter, D.R.Emplacement, crystallization and alteration of spinifex textured komatiitic basalt flows in the Archean Nondweni greenstone belt, southern Kaapvaal craton, South AfrContributions to Mineralogy and Petrology, Vol. 101, pp. 301-317. Database # 17781South AfricaCraton - Kaapvaal, Komatiite
DS1994-1925
1994
Versfeld, J.A.Wilson, A.H., Versfeld, J.A.The early Archean Nondweni greenstone belt, Kaapvaal Craton, 2.characteristics volcanic rocks, magma genesisPrecambrian Research, Vol. 67, No. 3-4, May pp. 277-320South AfricaGreenstone belt, Nondweni
DS1994-1927
1994
Versfeld, J.A.Wilson, A.M., Versfeld, J.A.The early Archean Nondweni greenstone belt, Kaapvaal Craton, SouthAfrica.2. Constraints on magma genesisPrecambrian Research, Vol. 67 No. 3-4, May pp. 277-320South AfricaGreenstone belt -Nondweni, Magma genesis
DS1910-0221
1911
Versfeld, W.Versfeld, W.Notes on the Geological Formation of Portions of German South West Africa.South African Journal of Science, Vol. 7, No. 8, PP. 332-339.Southwest Africa, NamibiaRegional Geology, Diamond Occurrences
DS1910-0478
1915
Versfeld, W.Versfeld, W.Some Recent Mineral Discoveries in NamaqualandSouth African Journal of Science, Vol. 11. JULY PP. 350-353.South AfricaMineral Resources, Diamonds, Current Activities
DS1910-0479
1915
Versfeld, W.Versfeld, W.Geological Structure of Portions of German Southwest AfricaSouth African Mining Journal, MARCH 20TH. P. 56.Southwest Africa, NamibiaStructure, Structural Geology
DS201512-1983
2015
Vershovskii, A.K.Vershovskii, A.K., Dmitriev, A.K.Pecularities of optical and ODMR spectra of nitrogen-vacancy color centers in diamond crystals.Journal of Physics Condensed Matter, Vol. 541, 1, pp. 12090-12094.TechnologyDiamond crystallography

Abstract: The optical and ODMR spectra of nitrogen vacancy (NV) centers in diamond were investigated as applied to the development of micro-scale diamond magnetometer sensor. It is shown that the NV0 center (unlike the NV? center) has an absorption line in the UV range. The inversion of the zero phonon line of the NV? center was observed and explained. ODMR signals in high magnetic fields (as compared with inner fields in the crystal) as well as in weak fields also were investigated. We propose the solution to the problem of the magnetometer sensitivity reduction at low magnetic field, that is of interest for quantum magnetometry applications. Peculiarities of optical and ODMR Spectra of Nitrogen-Vacancy Color Centers in Diamond Crystals.
DS201212-0756
2012
Verster, A.Verster, A., De Waal, D., Schall, R., Prins, C.A truncated Pareto model to estimate the under recoveru of large diamonds.Mathematical Geosciences, Vol. 44, 1, pp. 91-100TechnologyRecovery
DS201606-1126
2012
Verster, A.Verster, A., de Waal, D., Schall, R., Prins, C.A truncated Pareto model to estimate the under recovery of large diamonds. Bayesian approach.Mathematical Geosciences, Vol. 44, 1, pp. 91-100.TechnologyMetallurgy process

Abstract: The metallurgical recovery processes in diamond mining may, under certain circumstances, cause an under-recovery of large diamonds. In order to predict high quantiles or tail probabilities we use a Bayesian approach to fit a truncated Generalized Pareto Type distribution to the tail of the data consisting of the weights of individual diamonds. Based on the estimated tail probability, the expected number of diamonds larger than a specified weight can be estimated. The difference between the expected and observed frequencies of diamond weights above an upper threshold provides an estimate of the number of diamonds lost during the recovery process.
DS201704-0651
2017
Vertriest, W.Vertriest, W., Pardieu, V.Update on gemstone mining in northern Mozambique. RubyGems & Gemology, Vol. 52, 4, pp. 404-409.Africa, MozambiqueGemstones - ruby

Abstract: Northern Mozambique (figure 1) has gained attention for its rubies since a major discovery near Montepuez in 2009 (see McClure and Koivula, 2009; Pardieu and Lomthong, 2009; Pardieu and Chauvire, 2012; Pardieu et al., 2009, 2013; Hsu et al., 2014). Until the arrival of Gemfields in 2012, nearly all the production from this deposit came from unlicensed miners, known as garimpeiros. Between 2012 and 2016, Gemfields became a force in the ruby trade, supplying the market through regular auctions in Singapore and Jaipur. In 2016, two new players acquired ruby mining licenses around Montepuez: Mustang Resources and Metals of Africa. During a summer 2016 GIA field expedition, we visited these new sites. We also spent time at the Gemfields operation, in order to follow the development of what is already the world’s largest ruby mine. We also visited an interesting new pink spinel and tourmaline deposit near Ocua.
DS201909-2102
2019
Vertriest, W.Vertriest, W., Saeseaw, S.A decade of ruby from Mozambique: a review.Gems & Gemology, Vol. 55, 7, pp. 162-183.Africa, MozambiqueRuby

Abstract: In less than a decade, Mozambique has become the world’s most productive source for gem-quality ruby. Since the discovery in 2009, GIA has followed these deposits from the front lines, collecting data in the field and in the laboratory. The development of the deposit in Montepuez has been extremely interesting, with different players involved and different types of material unearthed. This article provides a summary and overview of the current knowledge about Mozambican ruby, including the history of mining and the market impact, as well as a comprehensive gemological characterization and discussion of the most common treatments applied to the stones. Much of the information in this article is based on the authors’ observations in the field and market as well as several publications (Pardieu et al., 2009, 2013, 2015; Saeseaw et al., 2018).
DS202003-0369
2019
Vertriest, W.Vertriest, W., Palke, A.C., Renfro, N.D.Field gemology: building a research collection and understanding the development of gem deposits.Gems & Gemology, Vol. 55, 4, pp. 490-511.United StatesGIA

Abstract: GIA’s field gemology program was established in late 2008 to support research on geographic origin determination of colored gemstones. By building and maintaining an extensive collection of gem materials with known origins, GIA’s research scientists have been able to study and analyze rubies, sapphires, emeralds, and other gemstones using the best available reference samples. This has led to improved origin determination services while supporting numerous research and education projects. To date the collection has accumulated during more than 95 field expeditions on six continents and currently includes more than 22,000 samples. GIA’s field gemology efforts require a thorough understanding of the gem trade, including the evolution of gemstone deposits and the development of treatments. It is important to recognize potential new deposits and gemstone enhancement procedures immediately because they can change rapidly and leave a lasting impact on the trade. Field expeditions also involve documenting the mines and local conditions. These factors provide context for the gemstones and are becoming increasingly important in the eyes of the public.
DS202203-0366
2021
Vertriest, W.Soonthorntantikul, W., Atikarnsakul, U., Vertriest, W.Blue sapphires from Mogok, Myanmar: a gemological review.Gems & Gemology, Vol. 57, pp. 292-317.Asia, Myanmarsapphire

Abstract: Burmese sapphires are among the most coveted colored gemstones in the world. The historical importance of this source and the fine quality of its high-grade material contribute to the legendary status of these gems. Since Mogok is such a long-known source, there are many classic studies available, but modern analytical data are often missing or not up to current standards. This article summarizes the characteristics of Burmese sapphires, including standard gemological properties, inclusion observations, and spectroscopic and trace element analyses. This information was collected from hundreds of blue sapphires that GIA's field gemologists sampled while visiting different mining regions in Mogok over the past decade. Our observations indicate that these sapphires show a wide range of blue color intensities but very consistent inclusion scenes. Trace element chemistry did not show any significant differences between various regions apart from a wider range of Fe concentrations in sapphires from north of Mogok. Rare observations such as orange fluorescence and unusual FTIR spectra can be attributed to the chemical compositions of the sapphires.
DS1998-1540
1998
Vervoort, J.Vervoort, J., Patchett, P.J., Blichert-Toft, AlbaredeHafnium neodymium isotopic covariance in the crust and mantle and constraints on the evolution of the depleted mantle.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1595-6.GreenlandGeochronology
DS201112-0717
2011
Vervoort, J.Naidoo, T., Zimmermann, U., Miyazaki, J.T., Vervoort, J.Isotope study of Neoproterozoic to lower Paleozoic successions of the southern Kalahari craton.Goldschmidt Conference 2011, abstract p.1523.AfricaRodinia
DS1997-1208
1997
Vervoort, J.D.Vervoort, J.D., Green, J.C.Origin of evolved magmas in the Midcontinent rift system: ND isotope evidence for melting Archean crust.Canadian Journal of Earth Sciences, Vol. 34, No. 4, April, pp. 521-535.Minnesota, MidcontinentGeochronology, Magma
DS1998-1541
1998
Vervoort, J.D.Vervoort, J.D.Early Earth neodymium isotopes: an unreliable record of crust mantle evolution?Geological Society of America (GSA) Annual Meeting, abstract. only, p.A207.GreenlandGeochronology, Mid Ocean Ridge Basalt (MORB) Mantle
DS1999-0770
1999
Vervoort, J.D.Vervoort, J.D., Blichert-Toft, J.Evolution of the depleted mantle: Hafnium isotope evidence from juvenile rocks through time.Geochimica et Cosmochimica Acta, Vol. 63, No. 3-4, Feb. 1, pp. 533-56.MantleGeochronology
DS2000-0980
2000
Vervoort, J.D.Vervoort, J.D., Patchett, P.J.Nf neodymium isotopic evolution of the lower crustEarth and Planetary Science Letters, Vol. 181, No. 1-2, Aug. 30, pp.115-30.MantleGeochronology
DS200712-0175
2007
Vervoort, J.D.Cheng, H., King, R.L., Nakamura, E., Vervoort, J.D.Rates of eclogitic metamorphism of subducted continental slab.Plates, Plumes, and Paradigms, 1p. abstract p. A169.ChinaUHP, Danie Shan
DS200812-0209
2008
Vervoort, J.D.Chen, H., King, R.L., Nakamura, E., Vervoort, J.D., Zhou, Z.Coupled Lu Hf and Sm Nd geochronology constraints garnet growth in ultra high pressure eclogites from the Dabie Orogen.Journal of Metamorphic Geology, in press availableChinaUHP, geochronology
DS200812-0213
2008
Vervoort, J.D.Cheng, H., King, R.L., Nakamura, E., Vervoort, J.D., Zhou, Z.Coupled Lu Hf and Sm Nd geochronology constrains garnet growth in ultra high pressure eclogites from the Dabie orogen.Journal of Metamorphic Geology, Vol. 26. 7, pp. 741-758.ChinaUHP
DS200812-0214
2008
Vervoort, J.D.Cheng, H., King, R.L., Nakamura, E., Vervoort, J.D., Zhou, Z.Coupled LuHf and SmNd geochronology constrains garnet growth in ultra high pressure eclogites from the Dabie orogen.Journal of Metamorphic Geology, Vol. 26, 7, Sept. pp. 741-758.ChinaUHP
DS201112-0180
2011
Vervoort, J.D.Cheng, H., Vervoort, J.D., Li, X., Zhang, C., Li, Q., Zheng, S.The growth interval of garnet in the UHP eclogites from the Dabie orogen, China.American Mineralogist, Vol. 96, 8-9, pp. 1300-1307.ChinaUHP
DS201903-0550
2019
Vervoort, J.D.Wang, D., Vervoort, J.D., Fisher, C.M., Cao, H. Li, G.Integrated garnet and zircon - titanate geochronology constrains the evolution of ultra high pressure terranes: an example from the Sulu orogen.Journal of Metamorphic Geology, in press availableChinaUHP

Abstract: Dating ultrahigh?pressure (UHP) metamorphic rocks provides important timing constraints on deep subduction zone processes. Eclogites, deeply subducted rocks now exposed at the surface, undergo a wide range of metamorphic conditions (i.e., deep subduction and exhumation) and their mineralogy can preserve a detailed record of chronologic information of these dynamic processes. Here we present an approach that integrates multiple radiogenic isotope systems in the same sample to provide a more complete timeline for the subduction?collision?exhumation processes, based on eclogites from the Dabie?Sulu orogenic belt in eastern China, one of the largest ultrahigh?pressure (UHP) terranes on Earth. In this study, we integrate garnet Lu?Hf and Sm?Nd ages with zircon and titanite U?Pb ages for three eclogite samples from the Sulu UHP terrane. We combine this age information with Zr?in?rutile temperature estimates, and relate these multiple chronometers to different P?T conditions. Two types of rutile, one present as inclusions in garnet and the other in the matrix, record the temperatures of UHP conditions and a hotter stage, subsequent to the peak pressure (“hot exhumation”), respectively. Garnet Lu?Hf ages (c. 238 to 235 Ma) record the initial prograde growth of garnet, while coupled Sm?Nd ages (c. 219 to 213 Ma) reflect cooling following hot exhumation. The maximum duration of UHP conditions is constrained by the age difference of these two systems in garnet (c. 235 to 220 Ma). Complementary zircon and titanite U?Pb ages of c. 235 ? 230 Ma and c. 216 ? 206 Ma provide further constraints on the timing of prograde metamorphism and the "cold exhumation", respectively. We demonstrate that timing of various metamorphic stages can thus be determined by employing complementary chronometers from the same samples. These age results, combined with published data from adjacent areas, show lateral diachroneity in the Dabie?Sulu orogeny. Three sub?blocks are thus defined by progressively younger garnet ages: western Dabie (243 ? 238 Ma), eastern Dabie?northern Sulu (238 ? 235 Ma,) and southern Sulu terranes (225 ? 220 Ma), which possibly correlate to different crustal slices in the recently proposed subduction channel model. These observed lateral chronologic variations in a large UHP terrane can possibly be extended to other suture zones.
DS201112-0181
2011
Vervoot, J.D.Cheng, H., Zhang, C., Vervoot, J.D., Wu, Y., Zheng, Y., Zheng, S., Zhou, Z.New Lu-Hf geochronology constrains the onset of continental subduction in the Dabie Orogen.Lithos, Vol. 121, 1-4, pp. 41-54.ChinaSubduction
DS1960-0410
1963
Verwoerd, W.J.Verwoerd, W.J.South African Carbonatites and their Probable Mode of Origin #1Ph.d. Thesis, University Stellenbosch, 163P.Southwest Africa, NamibiaCarbonatite, Kimberley
DS1960-0758
1966
Verwoerd, W.J.Verwoerd, W.J.South African Carbonatites and their Probable Mode of OriginStellenbosch University Annual Volume., SERIES A Vol. 41, NOT. 2, PP. 115-233.South Africa, Southwest Africa, NamibiaCarbonatite, Geology
DS1960-0893
1967
Verwoerd, W.J.Verwoerd, W.J.The Carbonatites of South Africa and Southwest AfricaGeological Survey of South Africa HANDBOOK, No. 6, 452P.Southwest Africa, NamibiaKimberley, Geology
DS1970-0208
1970
Verwoerd, W.J.Verwoerd, W.J.Economic Geology and Genesis of Kimberlite: a ReviewBras. Geol. Congres. Proceedings, Vol. 24, PP. 51-70.South Africa, Global, Brazil, Australia, RussiaGenesis, Diamond
DS1970-0651
1973
Verwoerd, W.J.Cornelissen, A.K., Verwoerd, W.J.The Bushmanland Kimberlites #11st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 71-74.Southwest Africa, NamibiaGeology
DS1975-0055
1975
Verwoerd, W.J.Cornelissen, A.K., Verwoerd, W.J.The Bushmanland Kimberlites #2Physics and Chemistry of the Earth., Vol. 9, PP. 71-80.Southwest Africa, NamibiaGeology
DS1985-0460
1985
Verwoerd, W.J.Moore, A.E., Verwoerd, W.J.The olivine melilitite kimberlite carbonatite suite of Namaqualand andBushmanland, South AfricaTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 281-294South AfricaPetrology, Carbonatite
DS1986-0833
1986
Verwoerd, W.J.Verwoerd, W.J.Mineral deposits associated with carbonatites and alkaline rocksIn: Mineral deposits of Southern Africa, Vol. 2, pp. 2173-2192South AfricaCarbonatite, Alkaline rocks
DS1986-0834
1986
Verwoerd, W.J.Verwoerd, W.J., Weder, E., Harmer, R.E.The Stukpan carbonatite: a new discovery in the Orange Free State GoldFieldGeocongress 86 abstract volume, pp. 899-902South AfricaCarbonatite
DS1989-1551
1989
Verwoerd, W.J.Verwoerd, W.J., Chevallier, L.Saltpeterkop, South Africa: a structural dome pierced by a carbonatitevolcanoNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 279 Abstract held June 25-July 1South AfricaCarbonatite
DS1990-1516
1990
Verwoerd, W.J.Verwoerd, W.J.The Saltpeterkop ring structure, Cape Province, South AfricaTectonophysics, Vol. 171, No. 1-4, January 1, pp. 275-285South AfricaAlkaline rocks, Tectonics
DS1992-1604
1992
Verwoerd, W.J.Verwoerd, W.J.A review of South Africa research on volcanic rocks and mantle processes, 1987-1991. (review)South African Journal of Science, Vol. 88, No. 6, June pp. 315-324. # JC095South AfricaMantle, Research overview
DS1993-1661
1993
Verwoerd, W.J.Verwoerd, W.J.United States Geological Survey (USGS) -type descriptive models of carbonatite-related mineral depositsTerra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 54.GlobalCarbonatite
DS1993-1662
1993
Verwoerd, W.J.Verwoerd, W.J.Update on carbonatites of South Africa and NamibiaSouth African Journal of Geology, Vol. 96, No. 3, Sept. pp. 75-95.South Africa, NamibiaCarbonatite, Review
DS1993-1663
1993
Verwoerd, W.J.Verwoerd, W.J., Weder, E.E., Harmer, R.E.The Stukpan carbonatite in the Orange Free State GoldfieldSouth African Journal of Geology, Vol. 96, No. 3, Sept. pp. 108-118.South AfricaCarbonatite, Stukpan
DS1994-1850
1994
Verwoerd, W.J.Verwoerd, W.J.Fluorite and rare earth ore controls in the Damaral and alkaline province ofNamibia.9th. IAGOD held Beijing, Aug.12-18., p. 691. abstractNamibiaAlkaline rocks, Carbonatite, Okorusu, Ondurakorume, Kalkfield
DS1995-1986
1995
Verwoerd, W.J.Verwoerd, W.J., Viljoen, E.A., Chevallier, L.Rare metal mineralization at the Salpeterkop carbonatite complex, Western Cape ProvinceJournal of African Earth Sciences, Vol. 21, No. 1, July pp. 171-186South AfricaCarbonatite, Deposit -Salpeterkop
DS1995-1987
1995
Verwoerd, W.J.Verwoerd, W.J., Viljoen, E.A., Chevallier, L.Rare metal mineralization at the Saltpeterkop carbonatite complex, Western Cape Province #1Journal of African Earth Sciences, Vol. 21, No. 1, July pp. 171-186.South AfricaCarbonatite, Deposit -Saltpeterkop
DS1995-1988
1995
Verwoerd, W.J.Verwoerd, W.J., Viljoen, E.A., Chevallier, L.Rare metal mineralization at the Saltpeterkop carbonatite complex, Western Cape #2Geological Society Africa 10th. Conference Oct. Nairobi, p. 134-5. Abstract.South AfricaCarbonatite, rare earths, Deposit -Saltpeterkop
DS1997-0521
1997
Verwoerd, W.J.Horstmann, U.E., Verwoerd, W.J.Carbon and oxygen isotope variations in southern African carbonatitesJournal of African Earth Sciences, Vol. 25, No. 1, July pp. 115-136.South AfricaCarbonatite, Geochronology
DS2000-0981
2000
Verwoerd, W.J.Verwoerd, W.J., Retief, E.A., Prins, P.The Etanenberg alkaline complex, NamibiaJournal of African Earth Sciences, p. 86. abstract.NamibiaAlkaline rocks
DS200812-1210
2008
Verwoerd, W.J.Verwoerd, W.J.Kamphaugite -(Y) from the Goudini carbonatite, South Africa.Canadian Mineralogist, Vol. 46, 4, August pp.Africa, South AfricaCarbonatite
DS200812-1211
2008
Verwoerd, W.J.Verwoerd, W.J.The Goudini carbonatite complex, South Africa: a re-appraisal.Canadian Mineralogist, Vol. 46, 4, August pp.Africa, South AfricaCarbonatite
DS1985-0698
1985
Verwoerd, W.S.Verwoerd, W.S.Comments on surface relaxation and reconstruction in diamond likecrystals.Solid State Communications, Vol. 55, No. 8, pp. 689-90.GlobalDiamond Morphology, Crystallography
DS1988-0731
1988
Verwoerd, W.S.Verwoerd, W.S.Quantum chemical investigation of fluorine in diamondNucl. Instrum. Methods Phys. Res. Sect. B., Vol. B35, No. 3-4, 12(II) pp. 509-512GlobalDiamond morphology, Fluorine
DS1990-0150
1990
Verwoerd, W.S.Badziag, P., Verwoerd, W.S., Ellis, W.P., Greiner, R.Nanometre-sized diamonds are more stable than graphiteNature, Vol. 343, No. 6255, Jan. 18, pp. 244-245GlobalDiamond crystallography
DS1997-1265
1997
Verwoort, J.D.Wirth, K.R., Verwoort, J.D., Naiman, Z.J.The Chengwatana Volcanics: petrogenesis of the southernmost volcanic rocks exposed in the MidcontinentCanadian Journal of Earth Sciences, Vol. 34, No. 4, April, pp. 536-548Wisconsin, MinnesotaVolcanics, Rift system
DS1998-0399
1998
VerzhakErinchek, Yu.M., Milshtein, E.D., Saltykov, VerzhakLocal depressions in country rock of kimberlites as a new explorationcriteria: Zolotitsa field.7th International Kimberlite Conference Abstract, pp. 208-10.Russia, YakutiaStructure - Vendian, Deposit - Zolotitsa
DS200712-1118
2006
Verzhak, D.V.Verzhak, D.V., Garanin, K.V.Diamond deposits of Arkhangelsk Oblast and environmental problems associated with their development.Moscow University Geology Bulletin, Vol. 60, 6, pp. 20-30.Russia, Kola PeninsulaEnvironmental
DS200912-0432
2009
Verzhak, V.Lehtonen, M., O'Brien, H., Peltonen, P., Kukkonen, I., Ustinov, V., Verzhak, V.Mantle xenocrysts from the Arkangelskaya kimberlite (Lomonosov); constraints on the composition and thermal state of the Diamondiferous lithospheric mantle.Lithos, in press availableRussia, Kola Peninsula, ArchangelDeposit - Lomonosov
DS1989-0127
1989
Verzhak, V.V.Blinova, G.K., Verzhak, V.V., Zakharchenko, O.D., Medvedeva, M.S.Impurity centers in diamonds from two kimberlite pipes in the Arkhangel diamond provinceSoviet Geology and Geophysics, Vol. 30, No. 8, pp. 122-125RussiaDiamond inclusions, Arkhangel
DS1989-1552
1989
Verzhak, V.V.Verzhak, V.V., Garanin, V.K., Kudryavtseva, G.P., MikhailenkoTo the problem of diamond potential relationship to the mineral composition of kimberlites and lamproites.(Russian)Geol. Rudn. Mestorozhd., (Russian), Vol. 31, No. 2, pp. 15-27RussiaKimberlite, Lamproite
DS1989-1553
1989
Verzhak, V.V.Verzhak, V.V., Garanin, V.K., Kudryavtseva, G.P., MikhailichenkoTo the problem of diamond potential relationship to the mineral composition of kimberlites andlamproites.(in Russian)Geol. Rudn. Mestorozh., (Russian), Vol. 31, No. 2, Mar-Apr. pp. 15-27RussiaLamproites, Diamond potential
DS1989-1554
1989
Verzhak, V.V.Verzhak, V.V., Garanin, V.K., Kudryavtseva, G.P., MikhaylichenkoMineralogic composition of kimberlites and lamproites as an indicator of diamond potentialInternational Geology Review, Vol. 31, No. 5, pp. 484-495RussiaLamproites, Kimberlites, Mineralogy -diamond poten
DS1990-0172
1990
Verzhak, V.V.Bartoshinskiy, Z.V., Bekesha, S.N., Verzhak, V.V., Vinnichenko, T.G.Non x-ray luminescence kimberlite diamonds.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 2, pp. 15-19RussiaDiamond morphology, Spectroscopy
DS1990-0797
1990
Verzhak, V.V.Kaminsky, F.B., Konyukhov, Yu.I., Verzhak, V.V., Khamai, M., KhenniDiamonds from the Algerian Sahara.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 5, October, pp. 76-80AlgeriaDiamond morphology, Occurrences
DS1993-0775
1993
Verzhak, V.V.Kaminsky, F.V., Verzhak, V.V., Dauev, Yu.M., Buima, T., BoukhalfaThe North-African Diamondiferous provinceRussian Geology and Geophysics, Vol. 33, No. 7, pp. 91-95.AlgeriaBled-el-Mas, Alluvial placers
DS1993-0776
1993
Verzhak, V.V.Kaminsky, F.V., Verzhak, V.V., Dauev, Yu.M., Buima, T., BoukhalfaThe North African Diamondiferous provinceRussian Geology and Geophysics, Vol. 33, No. 7, pp. 82-90GlobalKimberlite
DS200512-0026
2005
Verzhak, V.V.Appollonov, V.N., Verzhak, V.V., Garanin, K.V., Garanin, V.K., Kudryavtseva, G.P., Shlykov, V.G.Saponite from the Lomonosov diamond deposit.Moscow University Geology Bulletin, Vol. 59, 2, pp. 69-84.Russia, Kola Peninsula, ArchangelGeology
DS201312-0007
2013
Verzhak, V.V.Afanasiev, V.P., Aschepkov, I.V., Verzhak, V.V., O'Brien, H., Palessky, S.V.PT conditions and trace element variations of picroilmenites and pyropes from placers and kimberlites in the Arkhangelsk region, NW Russia.Journal of Asian Earth Sciences, Vol. 70, pp. 45-63.Russia, Kola Peninsula, ArchangelDeposit - Verkhotinskoe , Kepinskoe fields
DS2002-1663
2002
Vesare, B.Vesare, B., Rubatto, D., Hermann, J., Barzi, L.Evidence for Late Carboniferous subduction type magmatism in mafic ultramafic cumulates of southwest Tauren..Contributions to Mineralogy and Petrology, Vol. 142, No. 4, pp. 449-64.Europe, AlpsMagmatism - window
DS201504-0224
2015
Veselov, O.V.Tarakanov, R.Z., Veselov, O.V., Andreeva, M.Yu.The possible boundary of phase transitions at a depth of 350 km in the transition zone between continents and oceans.Doklady Earth Sciences, Vol. 460, 2, pp. 159-162.Russia, Far EastGeophysics - seismics
DS201906-1304
2019
Veselovskiy, R.V.Kogarko, L.N., Veselovskiy, R.V.Geodynamic origin of carbonatites from the absolute paleotectonic reconstructions. Maymecha-KotuyJournal of Geodynamics, Vol. 125, pp. 13-21.Russia, Siberiacarbonatites

Abstract: Geodynamic origin of carbonatites is debated for several decades. One of hypotheses links their origin to large-volume mantle plumes rising from the core-mantle boundary (CMB). Some evidence exists for temporal and spatial relationships between the occurrences of carbonatites and large igneous provinces (LIPs), and both carbonatites and LIPs can be related to mantle plumes. A good example is the carbonatites of the Maymecha-Kotuy Province in the Polar Siberia, which were formed at the same time as the Siberian superplume event at ca. 250 Ma. In this study we use a recently published absolute plate kinematic modelling to reconstruct the position of 155 Phanerozoic carbonatites at the time of their emplacement. We demonstrate that 69% of carbonatites may be projected onto the central or peripheral parts of the large low shear-wave velocity provinces (LLSVPs) in the lowermost mantle. This correlation provides a strong evidence for the link between the carbonatite genesis and the locations of deep-mantle plumes. A large group of carbonatites (31%) has no obvious links to LLSVPs and, on the contrary, they plot above the "faster-than-average S-wave" zones in the deep mantle, currently located beneath North and Central America and China. We propose that their origin may be associated with remnants of subducted slabs in the mantle.
DS201908-1820
2019
Veselovskiy, R.V.Veselovskiy, R.V., Thomson, S.N., Arzamastsev, A.A., Botsyun, S.B., Travin, A.V., Yudin, D.S., Samsonov, A.V., Stepanova, A.V.Thermochronology and exhumation history of the northeastern Fennoscandian Shield since 1.9 Ga: evidence from 40AR/39Ar and apatite fission track data from the Kola Peninsula.Tectonics, doi.org/10.1029 /2018TC005250Europe, Kola Peninsulageochronology

Abstract: Results from thermochronological studies have multiple applications to various problems in tectonics and landform evolution However, up to now a lack of thermochronological data from the northeastern Fennoscandian Shield has complicated the interpretation of tectonothermal evolution of the region Here, we use both new and previously published multimineral 40Ar/39Ar data (amphibole, mica, and feldspar) on the various Precambrian magmatic and metamorphic complexes to reconstruct the thermal history of NE Fennoscandia within the Kola Peninsula area in the interval 1900–360 Ma Using the apatite fission track method as well as a numerical model of the heating?cooling process of northeastern Fennoscandia's upper crust, we have reconstructed its thermal evolution for the interval 360–0 Ma According to our model, since Lapland?Kola orogenesis (1930–1905 Ma) northeastern Fennoscandia experienced a quasi?monotonous cooling with the average rate of ~0 15 °C/Myr, which is equal to an exhumation rate of ~1–2 m/Myr New apatite fission track data and time?temperature modeling reveal a “hidden” endogenous thermal event in the NE Fennoscandia that took place between 360 and 300 Ma This we attribute to an elevated geothermal gradient due to Baltica's drift over the African large low shear?wave velocity province in the lowest mantle and/or thermal blanketing by insulating Devonian?Carboniferous sedimentary/volcanic cover Our model is further supported by evidence of Late Devonian?Carboniferous rifting in the East and South?Western Barents Basin, as well as various 360–300 Ma magmatic events within SW Fennoscandia and the Baltic countries
DS201909-2103
2019
Veselovskiy, R.V.Veselovskiy, R.V., Thomson, S.N., Arzamastsev, A.A., Botsyun, S., Travin, A.V., Yudin, D.S., Samsonov, A.V., Stepanova, A.V.Thermochronology and exhumation history of the northeastern Fennoscandian shield since 1.9 Ga: evidence from 40Ar/39/Ar and apatite fission track data from the Kola Peninsula.Tectonics, Vol. 38, 7, pp. 2317-2337.Europe, Fennoscandia, Kola Peninsulageochronology

Abstract: Results from thermochronological studies have multiple applications to various problems in tectonics and landform evolution. However, up to now a lack of thermochronological data from the northeastern Fennoscandian Shield has complicated the interpretation of tectonothermal evolution of the region. Here, we use both new and previously published multimineral 40Ar/39Ar data (amphibole, mica, and feldspar) on the various Precambrian magmatic and metamorphic complexes to reconstruct the thermal history of NE Fennoscandia within the Kola Peninsula area in the interval 1900-360 Ma. Using the apatite fission track method as well as a numerical model of the heating?cooling process of northeastern Fennoscandia's upper crust, we have reconstructed its thermal evolution for the interval 360-0 Ma. According to our model, since Lapland?Kola orogenesis (1930-1905 Ma) northeastern Fennoscandia experienced a quasi?monotonous cooling with the average rate of ~0.15 °C/Myr, which is equal to an exhumation rate of ~1-2 m/Myr. New apatite fission track data and time?temperature modeling reveal a “hidden” endogenous thermal event in the NE Fennoscandia that took place between 360 and 300 Ma. This we attribute to an elevated geothermal gradient due to Baltica's drift over the African large low shear?wave velocity province in the lowest mantle and/or thermal blanketing by insulating Devonian?Carboniferous sedimentary/volcanic cover. Our model is further supported by evidence of Late Devonian?Carboniferous rifting in the East and South?Western Barents Basin, as well as various 360-300 Ma magmatic events within SW Fennoscandia and the Baltic countries.
DS202001-0024
2019
Veselovskiy, R.V.Kogarko, L.N., Veselovskiy, R.V.Geodynamic origin of carbonatites from the absolute paleoproterozoic reconstructions. Maymecha-KotuyJournal of Geodynamics, Vol. 125, pp. 13-21.Russia, Siberiacarbonatite

Abstract: Geodynamic origin of carbonatites is debated for several decades. One of hypotheses links their origin to large-volume mantle plumes rising from the core-mantle boundary (CMB). Some evidence exists for temporal and spatial relationships between the occurrences of carbonatites and large igneous provinces (LIPs), and both carbonatites and LIPs can be related to mantle plumes. A good example is the carbonatites of the Maymecha-Kotuy Province in the Polar Siberia, which were formed at the same time as the Siberian superplume event at ca. 250 Ma. In this study we use a recently published absolute plate kinematic modelling to reconstruct the position of 155 Phanerozoic carbonatites at the time of their emplacement. We demonstrate that 69% of carbonatites may be projected onto the central or peripheral parts of the large low shear-wave velocity provinces (LLSVPs) in the lowermost mantle. This correlation provides a strong evidence for the link between the carbonatite genesis and the locations of deep-mantle plumes. A large group of carbonatites (31%) has no obvious links to LLSVPs and, on the contrary, they plot above the "faster-than-average S-wave" zones in the deep mantle, currently located beneath North and Central America and China. We propose that their origin may be associated with remnants of subducted slabs in the mantle.
DS202007-1177
2020
Veselovskiy, R.V.Salnikova, E.B., Samsonov, A.V., Stepanova, A.V., Veselovskiy, R.V., Egorova, S.V., Arzamastsev, A.A., Erofeeva, K.G.Fragments of Paleoproterozoic large igneous provinces in northern Fennoscandia: baddeleyite U-Pb age data for mafic dykes and sills.Doklady Earth Sciences, Vol. 491, pp. 227-230.Europe, Russia, Kola Peninsulageochronology

Abstract: New data on the age of dolerite dikes in the NE part of the Kola province of the Fennoscandinavian shield and the picrodolerite sills that cut the dikes are presented. The results of U-Pb ID-TIMS baddeleyite dating indicate that dolerites were formed between 2508 ± 6 and 2513 ± 16 Ma ago, simultaneously with the intrusions of the Monchegorsk group. A comparison of the composition of the dolerites studied with dykes of the same age found in other Archean cratons shows their significant similarity and suggests their formation at the same large magmatic province. The age of baddeleyite from the picrodolerites sills at 2403 ± 12 Ma ago indicates an event of basic magmatism that was not previously established in this part of the Fennoscandinavian shield. It is possible that, along with dolerite dykes with an age of 2405 Ma and komatiites of the Vetreny belt of the Karelian craton, sills of the Kola province are a component of a unified large magmatic event.
DS202107-1116
2020
Veselovsky, R.E.Myshenkova, M.S., Zaitsev, V.A., Thomson, S., Latyshev, A.V., Zakharov, V.S., Bagdasaryan, T.E., Veselovsky, R.E.Thermal history of the Guli Pluton ( north of the Siberian platform) according to apatite fission-track dating and computer modeling. (carbonatite)Geodynamics & Tectonophysics, Vol. 11, pp. 75-87. pdfRussia, Siberiageothermometry

Abstract: We present the first results of fission-track dating of apatite monofractions from two rock samples taken from the Southern carbonatite massif of the world’s largest alkaline ultrabasic Guli pluton (~250 Ma), located within the Maymecha-Kotuy region of the Siberain Traps. Based on the apatite fission-track data and computer modeling, we propose two alternative model of the Guli pluton's tectonothermal history. The models suggest (1) rapid post-magmatic cooling of the studied rocks in hypabyssal conditions at depth about 1.5 km, or (2) their burial under a 2-3 km thick volcano-sedimentary cover and reheating above 110°C, followed by uplift and exhumation ca. 218 Ma.
DS201905-1050
2019
Veselovsky, R.V.Kogarko, L., Veselovsky, R.V.Geodynamic regimes of carbonatite formation according to the Paleo-reconstruction method.Doklady Earth Sciences, Vol. 484, 1, pp. 25-27.Russiacarbonatite

Abstract: Three models of geodynamic regimes of carbonatite formation are now actively being developed because of the high trace metal potential of this rock type: carbonatite melt generation within the lithosphere mantle; carbonatite relation to orogenic zones; the formation of carbonatite complexes as a result of the ascent of deep mantle plumes. The application for the first time of a modern model of “absolute” paleotectonic reconstructions combined with databases (both our own and published) demonstrates the general relationship of occurrences of the Phanerozoic carbonatite magmatism to Large Low S-wave Velocity Provinces: those are allocated in the lower mantle and are zones of generation of deep mantle plumes.
DS1991-1797
1991
Vesely, J.Vesely, J.Diamonds of the Republic of Sierra Leone.*CzechGeol. Pruzkum., *Czech, Vol. 33, No. 2, pp. 50-54Sierra LeoneOverview, Diamond production
DS1996-0013
1996
Veshev, S.A.Alekseev, S.G., Dukhanin, A.S., Veshev, S.A., Voroshilov, N.A.Some aspects of practical use of geoelectrochemical methods of exploration for deep seated mineralizationJournal of Geochem. Explor, Vol. 56, No. 1, June, pp. 79-86RussiaGeochemical exploration, Mineralization -at depth
DS201704-0618
2017
Vesolovskiy, R.V.Aramastsev, A.A., Vesolovskiy, R.V., Travin, A.V., Yudin, D.S.Paleozoic tholeiitic magmatism of the Kola Peninsula: spatial distribution, age, and relation to alkaline magmatism.Petrology, Vol. 25, 1, pp. 42-65.Russia, Kola PeninsulaMagmatism - alkaline

Abstract: This paper focuses on the occurrences of tholeiitic magmatism in the northeastern Fennoscandian shield. It was found that numerous dolerite dikes of the Pechenga, Barents Sea, and Eastern Kola swarms were formed 380-390 Ma ago, i.e., directly before the main stage of the Paleozoic alkaline magmatism of the Kola province. The isotope geochemical characteristics of the dolerites suggest that their primary melts were derived from the mantle under the conditions of the spinel lherzolite facies. The depleted mantle material from which the tholeiites were derived shows no evidence for metasomatism and enrichment in high fieldstrength and rare earth elements, whereas melanephelinite melts postdating the tholeiites were generated in an enriched source. It was shown that the relatively short stage of mantle metasomatism directly after the emplacement of tholeiitic magmas was accompanied by significant mantle fertilization. In contrast to other large igneous provinces, where pulsed intrusion of large volumes of tholeiitic magmas coinciding or alternating with phases of alkaline magmatism was documented, the Kola province is characterized by systematic evolution of the Paleozoic plume-lithosphere process with monotonous deepening of the level of magma generation, development of mantle metasomatism and accompanying fertilization of mantle materials, and systematic changes in the composition of melts reaching the surface.
DS1997-0609
1997
Vestin, J.Knudsen, T.L., Andersen, T., Vestin, J.Detrital zircon ages from southern Norway - implications for the Proterozoic evolution of southwest BalticContributions to Mineralogy and Petrology, Vol. 130, No. 1, pp. 47-58.NorwayGeochronology - zircon, Tectonics Baltic shield
DS1994-1016
1994
Vestyck, D.J.Lee, S.S., Minsek, D.W., Vestyck, D.J., Chen, P.Growth of diamond from atomic hydrogen and a supersonic free jet of methylradicals.Science, Vol. 263, March 14, pp. 1596-1598.GlobalDiamond synthesis
DS1980-0339
1980
Vetchaninov, V.A.Vetchaninov, V.A.Sources of Diamonds of Urals Placers in Connection with The article by Stepanov and Sychkin Entitled Estimating the Degree of Reliability of Some Diamond Finds.Soviet Geology And Geophysics, Vol. 21, No. 9, PP. 140-143.Russia, UralsOrigin, Alluvial Diamond Placers
DS1987-0763
1987
Vetchaninov, V.A.Vetchaninov, V.A.The Takat a suite of the middle Devonian- a source of diamonds in UralplacersSoviet Geology and Geophysics, Vol. 28, No. 4, pp. 130-133RussiaBlank
DS202202-0212
2021
Vetel, W.Roche, V., Leroy, S., Guillocheau, F., Revillon, S., Ruffet, G., Watremez, L., d'Acremont, E., Nonn, C., Vetel, W., Despinois, F.The Limpopo magma-rich transform margin, south Mozambique - pt. 2. Implications for the Gondwana breakup.Tectonics, e2021TC006914 Africa, Mozambiquegeophysics - seismics

Abstract: The rifted continental margins of Mozambique provide excellent examples of continental passive margins with a significant structural variability associated with magmatism and inheritance. Despite accumulated knowledge, the tectonic structure and nature of the crust beneath the South Mozambique Coastal Plain (SMCP) are still poorly known. This study interprets high-resolution seismic reflection data paired with data from industry-drilled wells and proposes a structural model of the Limpopo transform margin in a magma-rich context. Results indicate that the Limpopo transform margin is characterized by an ocean-continent transition that links the Beira-High and Natal valley margin segments and represents the western limit of the continental crust, separating continental volcano-sedimentary infilled grabens from the oceanic crust domain. These basins result from the emplacement of the Karoo Supergroup during a Permo-Triassic tectonic event, followed by an Early Jurassic tectonic and magmatic event. This latter led to the establishment of steady-state seafloor spreading at ca.156 Ma along the SMCP. A Late Jurassic to Early Cretaceous event corresponds to formation of the Limpopo transform fault zone. Which accommodated the SSE-ward displacement of Antarctica with respect to Africa. We define a new type of margin: the magma-rich transform margin, characterized by the presence of voluminous magmatic extrusion and intrusion coincident with the formation and evolution of the transform margin. The Limpopo transform fault zone consists of several syn-transfer and -transform faults rather than a single transform fault. The intense magmatic activity was associated primarily with mantle dynamics, which controlled the large-scale differential subsidence along the transform margin.
DS201707-1323
2017
Veter, M.Forster, M.W., Orelevic, D., Schmuck, H.R., Buhre, S., Veter, M., Mertz-Kraus, R., Foley, S.F., Jacob, D.E.Melting and dynamic metasomatism of mixed harzburgite + glimmerite mantle source: implications for the genesis of orogenic potassic magmas.Chemical Geology, Vol. 455, pp. 182-191.Mantlemetasomatism

Abstract: Tectonically young, orogenic settings are commonly the sites of post-collisional silica-rich ultrapotassic magmas with extreme K2O-contents of up to 9 wt% and K2O/Na2O > 2. Many experimental studies investigating the generation of these melts have concentrated on melting of homogenous phlogopite bearing peridotites, whereas geochemical signatures indicate the involvement of at least two types of source rocks: ultra-depleted and K and trace elements-enriched ones. We report the results of melting experiments at 1–2 GPa of mixed glimmerite and harzburgite, in which these rock types make up two halves each capsule. Melting begins in the glimmerite, and its metasomatic effects on the harzburgite are apparent at 1100 °C even before melt pools are visible. The first melts are Na-rich, seen in zoning of olivines and as growth of clinopyroxene in the harzburgite, but change at higher degrees of melting to produce a typical lamproite-like melt with K2O > 10 wt%. A major advantage of this study is the preservation of distinct melts in different parts of the capsule, which reflect a process of dynamic metasomatism: within the harzburgite matrix, the infiltrating melt derived from melting of the glimmerite changes consistently with the distance of travel through the harzburgite, enabling quantification of the metasomatic effects as an increase in SiO2 and K2O. This results principally from assimilation of orthopyroxene, which increases the Ol/Opx ratio of the residual harzburgite. The effects of quench olivine growth are recognizable and can be quantified due to a step-change in composition at the glimmerite/harzburgite border: the large total surface area of olivine and small melt fraction mean that the amount of quench olivine is high within the harzburgite, but negligible in the almost completely molten glimmerite. Melts of the glimmerite contain up to 8–10 wt% K2O and 53 wt% SiO2, which increase to 55–56 wt% after interaction with the harzburgite. Mediterranean lamproites resemble melts of glimmerite, whereas melts that have interacted with harzburgite are more similar to less potassic, but more SiO2-rich shoshonites of the Mediterranean region.
DS201711-2533
2017
Veter, M.Veter, M., Foley, S.F., Mertz-Kraus, R., Groschopf, N.Trace elements in olivine of ultramafic lamprophyres controlled by phlogopite rich mineral assemblages in the mantle source.Lithos, Vol. 292-293, pp. 81-95.Mantlelamprophyres

Abstract: Carbonate-rich ultramafic lamprophyres (aillikites) and associated rocks characteristically occur during the early stages of thinning and rifting of cratonic mantle lithosphere, prior to the eruption of melilitites, nephelinites and alkali basalts. It is accepted that they require volatile-rich melting conditions, and the presence of phlogopite and carbonate in the source, but the exact source rock assemblages are debated. Melts similar to carbonate-rich ultramafic lamprophyres (aillikites) have been produced by melting of peridotites in the presence of CO2 and H2O, whereas isotopes and trace elements appear to favor distinct phlogopite-bearing rocks. Olivine macrocrysts in aillikites are usually rounded and abraded, so that it is debated whether they are phenocrysts or mantle xenocrysts. We have analyzed minor and trace element composition in olivines from the type aillikites from Aillik Bay in Labrador, Canada. We characterize five groups of olivines: [1] mantle xenocrysts, [2] the main phenocryst population, and [3] reversely zoned crystals interpreted as phenocrysts from earlier, more fractionated, magma batches, [4] rims on the phenocrysts, which delineate aillikite melt fractionation trends, and [5] rims around the reversely zoned olivines. The main phenocryst population is characterized by mantle-like Ni (averaging 3400 ?g g? 1) and Ni/Mg at Mg# of 88-90, overlapping with phenocrysts in ocean island basalts and Mediterranean lamproites. However, they also have low 100 Mn/Fe of 0.9-1.3 and no correlation between Ni and other trace elements (Sc, Co, Li) that would indicate recycled oceanic or continental crust in their sources. The low Mn/Fe without high Ni/Mg, and the high V/Sc (2-5) are inherited from phlogopite in the source that originated by solidification of lamproitic melts at the base of the cratonic lithosphere in a previous stage of igneous activity. The olivine phenocryst compositions are interpreted to result from phlogopite and not high modal pyroxene in the source. The presence of kimberlites and ultramafic lamprophyres of Mesozoic age in Greenland indicates the persistence of a steep edge to the cratonic lithosphere at a time when this had been removed from the western flank in Labrador.
DS201809-2029
2018
Vetere, F.Gonzalez-Garcia, D., Petrelli, M., Behrens, H., Vetere, F., Fischer, L.A., Morgavi, D., Perugini, D.Diffusive exchange of trace elements between alkaline melts: implications for element fractionation and timescale estimations during magma mixing.Geochimica et Cosmochimica Acta, Vol. 233, pp. 95-114.Europe, Italyshoshonites

Abstract: The diffusive exchange of 30 trace elements (Cs, Rb, Ba, Sr, Co, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ta, V, Cr, Pb, Th, U, Zr, Hf, Sn and Nb) during the interaction of natural mafic and silicic alkaline melts was experimentally studied at conditions relevant to shallow magmatic systems. In detail, a set of 12 diffusion couple experiments have been performed between natural shoshonitic and rhyolitic melts from the Vulcano Island (Aeolian archipelago, Italy) at a temperature of 1200?°C, pressures from 50 to 500?MPa, and water contents ranging from nominally dry to ca. 2 wt.%. Concentration-distance profiles, measured by Laser Ablation ICP-MS, highlight different behaviours, and trace elements were divided into two groups: (1) elements with normal diffusion profiles (13 elements, mainly low field strength and transition elements), and (2) elements showing uphill diffusion (17 elements including Y, Zr, Nb, Pb and rare earth elements, except Eu). For the elements showing normal diffusion profiles, chemical diffusion coefficients were estimated using a concentration-dependent evaluation method, and values are given at four intermediate compositions (SiO2 equal to 58, 62, 66 and 70 wt.%, respectively). A general coupling of diffusion coefficients to silica diffusivity is observed, and variations in systematics are observed between mafic and silicic compositions. Results show that water plays a decisive role on diffusive rates in the studied conditions, producing an enhancement between 0.4 and 0.7 log units per 1 wt.% of added H2O. Particularly notable is the behaviour of the trivalent-only REEs (La to Nd and Gd to Lu), with strong uphill diffusion minima, diminishing from light to heavy REEs. Modelling of REE profiles by a modified effective binary diffusion model indicates that activity gradients induced by the SiO2 concentration contrast are responsible for their development, inducing a transient partitioning of REEs towards the shoshonitic melt. These results indicate that diffusive fractionation of trace elements is possible during magma mixing events, especially in the more silicic melts, and that the presence of water in such events can lead to enhanced chemical diffusive mixing efficiency, affecting also the estimation of mixing to eruption timescales.
DS201905-1038
2019
Vetlenyi, E.Guzmics, T., Berkesi, M., Bodnar, R.J., Fall, A., Bali, E., Milke, R., Vetlenyi, E., Szabo, C.Natrocarbonatites: a hidden product of three phase immiscibility. ( Oldoinyo Lengai)Geology, https://doi.org/ 10.1130/G46125.1 Africa, Tanzaniacarbonatite

Abstract: Earth’s only active natrocarbonatite volcanism, occurring at Oldoinyo Lengai (OL), Tanzania, suggests that natrocarbonatite melts are formed through a unique geological process. In the East African Rift, the extinct Kerimasi (KER) volcano is a neighbor of OL and also contains nephelinites hosting melt and fluid inclusions that preserve the igneous processes associated with formation of natrocarbonatite melts. Here, we present evidence for the presence of coexisting nephelinite melt, fluorine-rich carbonate melt, and alkali carbonate fluid. The compositions of these phases differ from the composition of OL natrocarbonatites; therefore, it is unlikely that natrocarbonatites formed directly from one of these phases. Instead, mixing of the outgassing alkali carbonate fluid and the fluorine-rich carbonate melt can yield natrocarbonatite compositions at temperatures close to subsolidus temperatures of nephelinite (<630-650 °C). Moreover, the high halogen content (6-16 wt%) in the carbonate melt precludes saturation of calcite (i.e., formation of calciocarbonatite) and maintains the carbonate melt in the liquid state with 28-41 wt% CaO at temperatures ?600 °C. Our study suggests that alkali carbonate fluids and melts could have commonly formed in the geological past, but it is unlikely they precipitated calcite that facilitates fossilization. Instead, alkali carbonates likely precipitated that were not preserved in the fossil nephelinite rocks. Thus, alkali carbonate fluids and melts have been so far overlooked in the geological record because of the lack of previous detailed inclusion studies.
DS201906-1298
2019
Vetlenyi, E.Guzmics, T., Berkesi, M, Bodnar, R.J., Fall, A., Bali, E., Milke, R., Vetlenyi, E., Szabo, C.Natrocarbonatites: a hidden product of three phase immiscibility.Geology, Vol. 47, 6, pp. 527-530.Africa, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Earth’s only active natrocarbonatite volcanism, occurring at Oldoinyo Lengai (OL), Tanzania, suggests that natrocarbonatite melts are formed through a unique geological process. In the East African Rift, the extinct Kerimasi (KER) volcano is a neighbor of OL and also contains nephelinites hosting melt and fluid inclusions that preserve the igneous processes associated with formation of natrocarbonatite melts. Here, we present evidence for the presence of coexisting nephelinite melt, fluorine-rich carbonate melt, and alkali carbonate fluid. The compositions of these phases differ from the composition of OL natrocarbonatites; therefore, it is unlikely that natrocarbonatites formed directly from one of these phases. Instead, mixing of the outgassing alkali carbonate fluid and the fluorine-rich carbonate melt can yield natrocarbonatite compositions at temperatures close to subsolidus temperatures of nephelinite (<630-650 °C). Moreover, the high halogen content (6-16 wt%) in the carbonate melt precludes saturation of calcite (i.e., formation of calciocarbonatite) and maintains the carbonate melt in the liquid state with 28-41 wt% CaO at temperatures ?600 °C. Our study suggests that alkali carbonate fluids and melts could have commonly formed in the geological past, but it is unlikely they precipitated calcite that facilitates fossilization. Instead, alkali carbonates likely precipitated that were not preserved in the fossil nephelinite rocks. Thus, alkali carbonate fluids and melts have been so far overlooked in the geological record because of the lack of previous detailed inclusion studies.
DS1995-1348
1995
Vetrin, V.Neymark, L.A., Nemchin, A.A., Vetrin, V., Salnikova, Ye.samarium-neodymium (Sm-Nd) and lead lead isotope systems in lower crustal xenoliths from dikes and pipes in southern Kola pen.Doklady Academy of Sciences, Vol. 329A, No. 3, April, pp. 214-221.Russia, Kola PeninsulaXenoliths, Geochronology
DS1996-0099
1996
Vetrin, V.Beard, A.D., Downes, H., Vetrin, V., Kempton, P.D.Petrogenesis of Devonian lamprophyre and carbonatite minor intrusions, Kandalaksha Gulf (Kola Peninsula).Lithos, Vol. 39, 1-2, Dec. pp. 93-119.RussiaCarbonatite, Kola Peninsula
DS1996-0100
1996
Vetrin, V.Beard, A.D., Downes, H., Vetrin, V., Kempton, P.D., MaduskiPetrogenesis of Devonian lamprophyre and carbonatite minor intrusions Kandalaksha Gulf, Kola Peninsula.Lithos, Vol. 39, pp. 93-119.Russia, Kola PeninsulaCarbonatite
DS200912-0797
2009
Vetrin, V.A.R.A.Vetrin, V.A.R.A., Lepekhina, E.A.N.A., Paderin, I.A.P.A., Rodionov, N.A.V.A.Stages of the lower crust formation of the Belomorian mobile belt, Kola Peninsula.Doklady Earth Sciences, Vol. 425, 2, pp. 269-273.Russia, Kola PeninsulaCraton
DS1998-1542
1998
Vetrin, V.R.Vetrin, V.R., Nemchin, A.A.The uranium-lead (U-Pb) age of zircon from a granulite xenolith in the diatreme on the Elovyi Island, southern Kola Peninsula.Doklady Academy of Sciences, Vol. 359A, No. 3, Mar-Apr. pp. 454-6.Russia, Kola PeninsulaGeochronology
DS2001-1200
2001
Vetrin, V.R.Vetrin, V.R.Two types of lower continental crust in the northern Baltic ShieldGeochemistry International, Vol. 39, No. 9, pp. 917-19.Baltic ShieldMantle mineralogy
DS2003-1427
2003
Vetrin, V.R.Vetrin, V.R., et al.Age of mantle metasomatism and formation of the Kola Paleozoic alkaline provinceDoklady Earth Sciences, Vol. 388, No. 1, pp. 219-222.Russia, ArkangelskMetasomatism
DS2003-1428
2003
Vetrin, V.R.Vetrin, V.R., Delenitsin, A.A.Proterozoic mantle crust interaction in the Archean basement of the Pechenga paleoriftDoklady Earth Sciences, Vol. 391, 5, pp.689-92.MantleTectonics - rifting not specific to diamonds
DS200412-2058
2003
Vetrin, V.R.Vetrin, V.R., Delenitsin, A.A.Proterozoic mantle crust interaction in the Archean basement of the Pechenga paleorift.Doklady Earth Sciences, Vol. 391, 5, pp.689-92.MantleTectonics - rifting not specific to diamonds
DS200612-0103
2006
Vetrin, V.R.Beard, A.D., Downes, H., Mason, P.R.D., Vetrin, V.R.Depletion and enrichment processes in the lithospheric mantle beneath the Kola Peninsula (Russia): evidence from spinel lherzolite wehrlite xenoliths.Lithos, in pressRussia, Kola PeninsulaMetasomatism, Kandalaksha
DS200712-0059
2007
Vetrin, V.R.Beard, A.D., Downes, H., Mason, P.R., Vetrin, V.R.Depletion and enrichment processes in the lithospheric mantle beneath the Kola Peninsula ( Russia): evidence from spinel lherzolite and wehrlite xenoliths.Lithos, Vol. 94, 1-4, pp. 1-24.RussiaXenoliths
DS200712-1119
2007
Vetrin, V.R.Vetrin, V.R., Lepekhina, E.N., Larionov, A.N., Presnyakov, S.L., Serov, P.A.Initial subalkaline magmatism of the Neoarchean alkaline province of the Kola Peninsula.Doklady Earth Sciences, Vol. 415, No. 5, June-July pp. 714-717.Russia, Kola PeninsulaAlkalic
DS201112-1089
2011
Vetrin, V.R.Vetrin, V.R.Deep structure and crustal growth of the northeastern Baltic Shield.Geochemistry International, Vol. 49, 1, pp. 101-105.Russia, Kola PeninsulaGeophysics - seismics
DS201904-0795
2018
Vetrin, V.R.Vetrin, V.R., Belousova, E.A., Kremenetsky, A.A.Lu-Hf isotopic systematics of zircon from lower crustal xenoliths in the Belomorian mobile belt.Geology of Ore Deposits, Vol. 60, 7, pp. 568-577.Russia, Kola Peninsulageochronology

Abstract: The structure, geochemistry, and U-Pb and Lu-Hf isotopic composition of zircon crystals from garnet granulite xenoliths of the lower crust in the Belomorian mobile belt have been studied. It has been established that Early Paleoproterozoic zircon, 2.47 Ga in age, is primary magmatic and formed during crystallization of mafic rocks in the lower crust. Meso- and Neoarchean zircons are xenogenic crystals trapped by mafic melt during its contamination with older crustal sialic rocks. Metamorphic zircon grains have yielded a Late Paleoproterozoic age (1.75 Ga). A Paleozoic age has been established for a magmatic crystal formed due to interaction of xenoliths with an alkaline ultramafic melt, which delivered xenoliths to surface. The U-Pb datings and Lu-Hf systematics of crystals have been used to delineate the stages of formation and transformation of the lower crust in this region.
DS202003-0370
2019
Vetrin, V.R.Vetrin, V.R.Isotopic geochemical systematics ( Sm-Nd, Lu-Hf) of Neoarchean subalkaline and alkaline rocks of the Keivy structure ( Kola Peninsula): their age and genetic relations.Geology of Ore Deposits, Vol. 61, 7, pp. 581-588. pdfRussia, Kola Peninsulamagmatism

Abstract: The Neoarchean subalkaline magmatism of the Keivy structure is expressed in the formation of the volcanoplutonic latite-monzonite-granite association (LMGA). The formation of LMGA magmas is assumed to occur due to melting of metasomatically altered mafic rocks during intrusion into the lower crust of basaltic melts initial for rocks of the dike complex and gabbro-labradorite massifs. The alkaline granites associated with LMGA have a close U-Pb age but a later formation time based on the geological data. With respect to LMGA, alkali granites have increased concentrations of SiO2, alkalis (K2O/Na2O = 1.1-1.4), iron (F# = 84-98%), a high agpaitic index (Kagp = 0.86-1.2), and lower quantities of TiO2, MgO, Fetot, and Al2O3, which probably resulted from the higher degree of differentiation of their initial melts compared to LMGA.
DS1991-0268
1991
Veys, B.T.Chernysheva, Ye.A., Nechelyustov, G.N., mKvitko, T.D., Veys, B.T.Compositional evolution of perovskite in the alkali rocks of the lower Sayan carbonatite complexGeochemistry International, Vol. 28, No. 4, pp. 102-108RussiaCarbonatite, Perovskite, mineralogy
DS201712-2713
2017
Vezinet, A.Nicoli, G., Thomassot, E., Schannor, M., Vezinet, A., Jovovic, I.Constraining a Precambrian Wilson Cycle lifespan: an example from the ca. 1.8Ga Nagssugtoqidian Orogen, southeastern Greenland.Lithos, in press available 68p.Europe, GreenlandWilson cycle

Abstract: In the Phanerozoic, plate tectonic processes involve the fragmentation of the continental mass, extension and spreading of oceanic domains, subduction of the oceanic lithosphere and lateral shortening that culminate with continental collision (i.e. Wilson cycle). Unlike modern orogenic settings and despite the collection of evidence in the geological record, we lack information to identify such a sequence of events in the Precambrian. This is why it is particularly difficult to track plate tectonics back to 2.0 Ga and beyond. In this study, we aim to show that a multidisciplinary approach on a selected set of samples from a given orogeny can be used to place constraints on crustal evolution within a P-T-t-d-X space. We combine field geology, petrological observations, thermodynamic modelling (Theriak-Domino) and radiogenic (U-Pb, Lu-Hf) and stable isotopes (?18O) to quantify the duration of the different steps of a Wilson cycle. For the purpose of this study, we focus on the Proterozoic Nagssugtoqidian Orogenic Belt (NOB), in the Tasiilaq area, South-East Greenland. Our study reveals that the Nagssugtoqidian Orogen was the result of a complete three stages juvenile crust production (Xjuv) - recycling/reworking sequence: (I) During the 2.60-2.95 Ga period, the Neoarchean Skjoldungen Orogen remobilised basement lithologies formed at TDM 2.91 Ga with progressive increase of the discharge of reworked material (Xjuv from 75% to 50%; ?18O: 4-8.5‰). (II) After a period of crustal stabilization (2.35-2.60 Ga), discrete juvenile material inputs (?18O: 5-6‰) at TDM 2.35 Ga argue for the formation of an oceanic lithosphere and seafloor spreading over a period of ~ 0.2 Ga (Xjuv from < 25% to 70%). Lateral shortening is set to have started at ca. 2.05 Ga with the accretion of volcanic/magmatic arcs (i.e. Ammassalik Intrusive Complex) and by subduction of small oceanic domains (M1: 520 ± 60 °C at 6.6 ± 1.4 kbar). (III) Continental collision between the North Atlantic Craton and the Rae Craton occurred at 1.84-1.89 Ga. Crustal thickening of ~ 25 km was accompanied by regional metamorphism M2 (690 ± 20 °C at 6.25 ± 0.25 kbar) and remobilization of pre-existing supracrustal lithologies (Xjuv ~ 40%; ?18O: 5-10.5‰). Rates and durations obtained for seafloor spreading (175 ± 25 Ma), subduction (125 ± 75 Ma) and continental collision (ca. 60 Ma) are similar to those observed in Phanerozoic Wilson Cycle but differ from what was estimated for Archean terrains. Therefore, timespans of the different steps of a Wilson cycle might have progressively changed over time as a response to the progressive cratonization of the lithosphere.
DS201801-0075
2018
Vezinet, A.Vezinet, A., Moyen, J-F., Stevens, G., Nicoli, G., Laurent, O., Couzinie, S., Frei, D.A record of 0.5 Ga of evolution of the continental crust along the northern edge of the Kaapvaal Craton, South Africa: consequences for the understanding of Archean geodynamic processes.Precambrian Research, Vol. 305, pp. 310-326.Africa, South Africacraton - Kaapvaal

Abstract: Geodynamics of crustal growth and evolution consist in one of the thorniest questions of the early Earth. In order to solve it, Archean cratons are intensively studied through geophysical, geochemical and geochronological investigations. However, timing and mechanisms leading to accretion and stabilization of crustal blocks are still under question. In this study, new information on the evolution of Archean cratons is provided through complementary approaches applied to the northern margin of the Archean Kaapvaal craton (KC). The study area comprises the Pietersburg Block (PB) and the terrane immediately adjacent to the North: the Southern Marginal Zone of the Limpopo Complex (SMZ). We present a comprehensive petro-metamorphic study coupled with LA-ICP-MS U-Pb isotope examination of both Na- and K-rich granitoids from the two areas. This dataset points toward a new interpretation of the northern KC (PB?+?SMZ). Two significant magmatic events are newly recognized: (i) a ca. 3.2?Ga event, and (ii) a protracted magmatic event between ca. 2.95–2.75?Ga. These events affected in both investigated areas and are unrelated to the ca. 2.7?Ga-old event usually attributed to the SMZ. More importantly, phase equilibrium modelling of several lithologies from the SMZ basement points to middle-amphibolite facies conditions of equilibration instead of granulite-facies conditions historically assumed. This study has both important regional and global implications. Firstly, the presence of a continuous basement from the Thabazimbi-Murchison Lineament to the Palala Shear Zone, different than Central Zone of the Limpopo Complex basement, implies a complete reviewing of the whole Limpopo Complex concept. Secondly, the geometry observed in the northern Kaapvaal craton is assumed to testify for a complete accretionary orogenic sequence with formation of both mafic and TTG lithologies through arc-back arc geodynamic. This was followed by a long-lived lateral compression triggering partial melting of the lower continental crust and emplacement of Bt-granitoids bodies that stabilizes the continental crust. Lastly, partial melting of the underlying enriched mantle stabilized the entire lithosphere allowing long-term preservation of the crustal block.
DS202103-0419
2021
Vezinet, A.Vezinet, A., Pearson, A.D., Thomassot, E.Effects of contamination on whole rock isochrons in ancient rocks: a numerical modelling approach.Lithos, in press available, 44p. PdfGlobalmetamorphism

Abstract: Radiometric decay systems have played a crucial role in developing our understanding of the evolution of the early Earth. There are two main types of protocols for isotope measurements in geological materials: (i) bulk dissolution of rocks, or whole-grains and (ii) spatially resolved techniques (laser-ablation or ion-beam). These two approaches have sometimes led to results that are not easily reconciled for early Earth crustal rocks (? 3.6?Ga). While initial radiogenic isotope signatures (e.g. initial 176Hf/177Hf or initial 143Nd/144Nd) obtained from whole-rock protocols are significantly above chondritic values, indicative of extensive chemical differentiation of the mantle before 3.6?Ga, data from spatially resolved analysis of individual mineral growth domains point toward much less dramatic differentiation. This is indicated by the majority of data falling close to models of Earth's mantle that had not experienced major silicate melt removal into the crust. These data show chondritic or sub-chondritic signatures. Interpretations of whole rock isochrons are built on assumptions about the history and relationship of a number of different samples to each other. At the heart of these assumptions, the effects of secondary process-such as metasomatism-on isotopic compositions and consequently on the age and initial ratio of isochrons, are often considered negligible. In order to evaluate the possible effects of metasomatism and metamorphism on co-genetic igneous suites we modelled the impact of contamination by an external component on both the isochron slope (the apparent age) and the isochron intercept (the initial radiogenic isotope signature). A significant outcome is that the age significance of some of the modified isochron arrays remains to a large extent within uncertainty of the original crystallisation age of the igneous suite. In other words, the original age signature is preserved, but with lower precision. The intercept of the isochron, from which the initial isotope ratio is calculated, however is often significantly modified, which has consequences for the interpretation of these signatures. Our results provide an explanation for the discrepancy between whole-rock and spatially-resolved results observed in early Earth material. Lastly, our results, applied to studies of ancient crustal rocks, are interpreted as indicative of no significantly depleted mantle domains before 3.6?Ga, and no Hfsingle bondNd isotopes decoupling at that time.
DS201412-0274
2014
Vezzoli, G.Garzanti, E., Resentini, A., Ando, S., Vezzoli, G., Pereira, A., Vermeesch, P.Physical controls on sand and composition and relative durability of detrital minerals during ultra-long distance littoral and aeolian transport ( Namibia and southern Angola).Sedimentology, Vol. 62, 4, pp. 971-996.Africa, Namibia, AngolaDiamondiferous littoral deposits
DS201802-0238
2018
Vezzoli, G.Garzanti, E., Dinis, P., Vermeesch, P., Ando, S., Hahn, A., Huvi, J., Limonta, M., Padoan, M., Resentini, A., Rittner, M., Vezzoli, G.Sedimentary processes controlling ultralong cells of littoral transport: placer formation and termination of the Orange sand highway in southern Angola.Sedimentology, Vol. 65, 2, pp. 431-460.Africa, Angolaplacers, alluvials

Abstract: This study focuses on the causes, modalities and obstacles of sediment transfer in the longest cell of littoral sand drift documented on Earth so far. Sand derived from the Orange River is dragged by swell waves and persistent southerly winds to accumulate in four successive dunefields in coastal Namibia to Angola. All four dunefields are terminated by river valleys, where aeolian sand is flushed back to the ocean; and yet sediment transport continues at sea, tracing an 1800 km long submarine sand highway. Sand drift would extend northward to beyond the Congo if the shelf did not become progressively narrower in southern Angola, where drifting sand is funnelled towards oceanic depths via canyon heads connected to river mouths. Garnet-magnetite placers are widespread along this coastal stretch, indicating systematic loss of the low-density feldspatho-quartzose fraction to the deep ocean. More than half of Moçamedes Desert sand is derived from the Orange River, and the rest in similar proportions from the Cunene River and from the Swakop and other rivers draining the Damara Orogen in Namibia. The Orange fingerprint, characterized by basaltic rock fragments, clinopyroxene grains and bimodal zircon-age spectra with peaks at ca 0•5 Ga and ca 1•0 Ga, is lost abruptly at Namibe, and beach sands further north have abundant feldspar, amphibole-epidote suites and unimodal zircon-age spectra with a peak at ca 2•0 Ga, documenting local provenance from Palaeoproterozoic basement. Along with this oblique-rifted continental margin, beach placers are dominated by Fe-Ti-Cr oxides with more monazite than garnet and thus have a geochemical signature sharply different from beach placers found all the way along the Orange littoral cell. High-resolution mineralogical studies allow us to trace sediment dispersal over distances of thousands of kilometres, providing essential information for the correct reconstruction of ‘source to sink’ relationships in hydrocarbon exploration and to predict the long-term impact of man-made infrastructures on coastal sediment budgets.
DS1990-0917
1990
VialetteLemoine, S., Tempier, P., Bassot, J.P., Caen-vachette, M., VialetteThe Burkinian orogenic cycle, precursor of the Eburnian orogeny in WestAfricaGeological Journal, Vol. 25, pp. 171-188Ghana, Ivory Coast, Burkina Faso, west AfricaTectonics, Orogeny
DS1993-1319
1993
Vialette, Y.Rohon, M.-L., Vialette, Y., Clar, T., Roger, G., Ohnenstetter, D., Vidal, Ph.Aphebian mafic-ultramafic magmatism in the Labrador trough (New Quebec):its age and the nature of its mantle source.Canadian Journal of Earth Sciences, Vol. 30, No. 8, August pp. 1582-1593.QuebecCrustal contamination, Ultramafics
DS1993-1393
1993
Viave, J.Schmitt, H.R., Cameron, E.M., Hall, G.E.M., Viave, J.Mobilization of gold into lake sediments from acid and alkaline mineralized environments in the southern Canadian shield: gold in lake sediments andnat.watersJournal of Geochemical Exploration, Vol. 48, No. 3, August pp. 329-358Ontario, Saskatchewan, ManitobaGold geochemistry, Alkaline rocks
DS1981-0418
1981
Vicary, M.J.Vicary, M.J., Csr ltd, ASHTON MINING LTD.El 1864 Yambarran Range, Final Report on ExplorationNorthern Territory Geological Survey Open File., No. CR 81 115, 41P.Australia, Northern TerritoryProspecting, Sampling, Stream Sediment, Soil, Rock Chip
DS1989-1555
1989
Vicat, J-P.Vicat, J-P., Gioan, P., Albouy, Y., Cornacchia, M., Giorgi, L.Evidence of Upper Proterozoic rifts buried under the Phanerozoic of the Zaire basin on the western border of the Congo craton.(in French)Comptes Rendus, (in French), Vol. 309, No. 11, pp. 1207-1214Democratic Republic of CongoTectonics, Craton
DS201909-2092
2019
Vicentini, N.Stoppa, F., Schiazza, M., Rosatelli, G., Castorina, F., Sharygin, V.V., Ambrosio, A., Vicentini, N.Italian carbonatite system: from mantle to ore deposit.Ore Geology Reviews, in press available, 59p. PdfEurope, Italycarbonatite

Abstract: A new discovery of carbonatites at Pianciano, Ficoreto and Forcinelle in the Roman Region demonstrates that Italian carbonatites are not just isolated, mantle xenoliths-bearing, primitive diatremic rocks but also evolved sub-type fluor-calciocarbonatite (F?10 wt.%) associated with fluor ore (F?30 wt.%). New data constrain a multi-stage petrogenetic process, 1-orthomagmatic, 2-carbothermal, 3-hydrothermal. Petrography and geochemistry are conducive to processes of immiscibility and decarbonation, rather than assimilation and crystal fractionation. A CO2-rich, ultra-alkaline magma is inferred to produce immiscible melilite leucitite and carbonatite melts, at lithospheric mantle depths. At the crustal level and in the presence of massive CO2 exsolution, decarbonation reactions may be the dominant processes. Decarbonation consumes dolomite and produces calcite and periclase, which, in turn, react with silica to produce forsterite and Ca silicates (monticellite, melilite, andradite). Under carbothermal conditions, carbonate breakdown releases Sr, Ba and LREE; F and S become concentrated in residual fluids, allowing precipitation of fluorite and barite, as well as celestine and anhydrite. Fluor-calciocarbonatite is the best candidate to exsolve fluids able to deposit fluor ore, which has a smaller volume. At the hydrothermal stage, REE concentration and temperature dropping allow the formation of LREEF2+ and LREECO3+ ligands, which control the precipitation of interstitial LREE fluorcarbonate and silicates -(bastnäsite-(Ce)- Ce(CO3)F and -britholite-(Ce)- (Ce,Ca)5(SiO4,PO4)3(OH,F) . Vanadates such as wakefieldite, CeVO4, vanadinite, Pb5(VO4)3Cl and coronadite Pb(Mn4+6 Mn3+2)O16 characterise the matrix. At temperatures of ?100°C analcime, halloysite, quartz, barren calcite, and zeolites (K-Ca) precipitate in expansion fractures, veins and dyke aureoles.
DS201911-2566
2019
Vicentini, N.Stoppa, F., Schiazza, M., Rosatelli, G., Castorina, F., Sharygin, V.V., Ambrosio, F.A., Vicentini, N.Italian carbonatite system: from mantle to ore deposit.Ore Geology Reviews, Vol. 114, 17p. PdfEurope, Italycarbonatite

Abstract: A new discovery of carbonatites at Pianciano, Ficoreto and Forcinelle in the Roman Region demonstrates that Italian carbonatites are not just isolated, mantle xenoliths-bearing, primitive diatremic rocks but also evolved sub-type fluor-calciocarbonatite (F~10 wt.%) associated with fluor ore (F~30 wt.%). New data constrain a multi-stage petrogenetic process, 1-orthomagmatic, 2-carbothermal, 3-hydrothermal. Petrography and geochemistry are conducive to processes of immiscibility and decarbonation, rather than assimilation and crystal fractionation. A CO2-rich, ultra-alkaline magma is inferred to produce immiscible melilite leucitite and carbonatite melts, at lithospheric mantle depths. At the crustal level and in the presence of massive CO2 exsolution, decarbonation reactions may be the dominant processes. Decarbonation consumes dolomite and produces calcite and periclase, which, in turn, react with silica to produce forsterite and Ca silicates (monticellite, melilite, andradite). Under carbothermal conditions, carbonate breakdown releases Sr, Ba and LREE; F and S become concentrated in residual fluids, allowing precipitation of fluorite and barite, as well as celestine and anhydrite. Fluor-calciocarbonatite is the best candidate to exsolve fluids able to deposit fluor ore, which has a smaller volume. At the hydrothermal stage, REE concentration and temperature dropping allow the formation of LREEF2+ and LREECO3+ ligands, which control the precipitation of interstitial LREE fluorcarbonate and silicates -(bastnäsite-(Ce)- Ce(CO3)F and -britholite-(Ce)- (Ce,Ca)5(SiO4,PO4)3(OH,F) . Vanadates such as wakefieldite, CeVO4, vanadinite, Pb5(VO4)3Cl and coronadite Pb(Mn4+6 Mn3+2)O16 characterise the matrix. At temperatures of =100°C analcime, halloysite, quartz, barren calcite, and zeolites (K-Ca) precipitate in expansion fractures, veins and dyke aureoles.
DS2001-0465
2001
Vicenzi, E.P.Heaney, P.J., Vicenzi, E.P., Giannuzzi, L., Livi, K.J.T.Focused ion beam milling: a method of site specific sample extraction for microanalysis of Earth materials.American Mineralogist, Vol. 86, pp. 1094-99.GlobalMicroanalysis - TEM, FIB
DS2002-0690
2002
Vicenzi, E.P.Heaney, P.J., Vicenzi, E.P., Subarnakha, De.Microstructural distinctions between two polycrystalline diamond variatiesEos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.Brazil, Central African RepublicDiamond - morphology, carbonado
DS2002-1664
2002
Vicenzi, E.P.Vicenzi, E.P., Heaney, P.J., Snyder, K.Radiation halos, a rare microstructure in diamonds from the Central African RepublicEos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.Central African RepublicDiamond - morphology, carbonado
DS200412-0433
2004
Vicenzi, E.P.De, S., Heaney, P.J., Fei, Y., Vicenzi, E.P.Microstructural study of synthetic sintered diamond and comparsion with carbonado, a natural polycrstalline diamond.American Mineralogist, Vol. 89, 2-3, Feb. Mar. pp. 439-46.TechnologyDiamond morphology
DS200512-0412
2005
Vicenzi, E.P.Heaney, P.J., Vicenzi, E.P., De, S.Strange diamonds: the mysterious origins of carbonado and framesite.Elements, Vol. 1, 2, March pp. 85-90.South America, Brazilframesite, polycrystalline, mineralogy
DS2002-0315
2002
VicettaConticelli, S., D'Antonio, M., Pinarelli, L., VicettaSource contamination and mantle heterogeneity - genesis of Italian potassic andMineralogy and Petrology, Vol. 74, 2-4, pp. 189-222.Italy, TuscanyGeochronology, Alkaline rocks
DS200612-1479
2005
Vichi, G.Vichi, G., Stoppa, F., Wall, F.The carbonate fraction in carbonatitic Italian lamprophyres.Lithos, Vol. 85, 1-4, Nov-Dec. pp. 154-170.Europe, ItalyCarbonatite
DS1990-1517
1990
Vick, S.G.Vick, S.G.Planning, design and analysis of tailings damsBiTech, 370p. approx. $ 81.00GlobalTailings daM., Book -ad
DS1994-1851
1994
Vicker, P.A.Vicker, P.A., Schulze, D.J.Garnet peridotite xenoliths in Kirkland Lake kimberlitesGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p.OntarioGeochemistry, Kirkland Lake area
DS1995-1989
1995
Vicker, P.A.Vicker, P.A.Petrology of peridotite xenoliths from kimberlite near Kirkland Lake, Ontario.Msc. Thesis, University Of Toronto, OntarioXenoliths, Deposit -Kirkland Lake
DS1997-1209
1997
Vicker, P.A.Vicker, P.A.Garnet peridotite xenoliths from kimberlite near Kirkland LakeMsc. Thesis U. Toronto, 125p.OntarioXenoliths, Petrology
DS201112-0374
2011
Vickers, J.Glikson, A.Y., Vickers, J.Asteroid impact connections of crustal evolution.Australian Journal of Earth Sciences, Vol.57, 1, pp. 79-95.MantleImpacts
DS201905-1059
2019
Vickova Zicova, Z.Mortet, V., Vickova Zicova, Z., Taylor, A., Davydova, M., Frank, O,m Hubik, P., Lorincik, J., Aleshin, M.Determination of atomic boron concentration in heavily boron-doped diamond by Raman spectroscopy.Diamond & Related Materials, Vol. 93, pp. 54-58.Globalspectroscopy

Abstract: Raman spectroscopy has been foreseen as a simple and non-destructive characterization method to determine the boron concentration in heavily boron-doped diamond with metallic conductivity. However, currently available empirical studies are not fully satisfactory for enabling accurate determination of the boron concentration in diamond. Here, we study Raman spectra of epitaxial boron-doped diamond as a function of the boron concentration and the excitation wavelength. The zone center phonon and the phonon density of state maximum (at ca. 1200?cm?1) lines are analyzed using a decoupled double Fano-function. This analysis method accurately describes the observed variation of the asymmetric parameters with atomic boron concentration and the photon excitation energy and enables the determination of the atomic boron concentration from the parameters of the examined Raman lines.
DS1860-0256
1876
VickusVickusDiamond Fields, South AfricaVickus And Co., 25P.Africa, South Africa, Cape ProvinceTravelogue
DS1999-0272
1999
Victor, D.G.Grubler, A., Nakicenovic, N., Victor, D.G.Dynamics of energy technologies and global changeEnergy Policy, Vol. 27, pp. 247-80.GlobalGlobal warming, Modelling - changes, energy
DS2003-1172
2003
Victor, T.Ritter, O., Weckmann, U., Victor, T., Haak, V.A magnetotelluric study of the Damara belt in Namibia: 1. regional scale conductivityPhysics of the Earth and Planetary Interiors, Vol. 138, 2, July 16, pp. 71-90.NamibiaGeophysics - magnetics
DS200412-1673
2003
Victor, T.Ritter, O., Weckmann, U., Victor, T., Haak, V.A magnetotelluric study of the Damara belt in Namibia: 1. regional scale conductivity anomalies.Physics of the Earth and Planetary Interiors, Vol. 138, 2, July 16, pp. 71-90.Africa, NamibiaGeophysics - magnetics
DS1990-1356
1990
Victory, D.Shurr, G., Watkins, I., Victory, D., Tozer, M.Geological significance of linear features visible onLand sat images inwest central MinnesotaInstitute on Lake Superior Geology Proceedings Volume, 36th. Annual Meeting held May 9-12, Thunder Bay pMinnesotaRemote sensing, Structure
DS1995-1990
1995
Vidal, C.E.Vidal, C.E.Bolivia, Argentina, Chile and Peru ... overview from SEG's regionalrepresentativeSeg Newsletter, No. 21, April pp. 14-17Bolivia, Argentina, Chile, PeruExploration activities, Brief overview
DS1994-1748
1994
Vidal, F.Taylor, R.N., Nesbitt, R.W., Vidal, F., Harmon, R.S., et al.Mineralogy, chemistry and genesis of the boninite series volcanics, Chichijima, Bonin Islands, Japan.Journal of Petrology, Vol. 35, No. 3, June pp. 577-618.JapanBoninites
DS1988-0127
1988
Vidal, G.Chorowicz, J., Guezlane, M., Rudant, J., Vidal, G.Use of MOMS-1 dat a for geological mapping of the Aswa lineament(East African Rift)National Technical Information Service, In ESA Proceedings 4th. International Colloquium in Spectral Signatures in Remote, N89 10382/4 4p. April 1988 Entire Conference $ 49.95TanzaniaTectonics, Remote Sensing
DS1994-1852
1994
Vidal, M.Vidal, M., Alric, G.The Paleoproterozoic Birimian of Haute Comoe in the West African craton, Ivory Coast: a transtensional back-arc basinPrecambrian Research, Vol. 65, No. 1-4, January pp. 207-230GlobalCraton, Birimian
DS1998-0435
1998
Vidal, N.Flueh, E.R., Vidal, N., Zelt, C.Seismic investigation of the continental margin off and on shore ValparaisoChileTectonophysics, Vol. 288, No. 1-4, Mar. pp. 251-264ChileTectonics, Geophysics - seismic
DS201711-2534
2017
Vidal, O.Vidal, O., Rostom, F., Francois, C., Giraud, G.Global trends in metal consumption and supply: the raw material-energy nexus.Elements, Vol. 13, pp. 319-324.Globalresources

Abstract: The consumption of mineral resources and energy has increased exponentially over the last 100 years. Further growth is expected until at least the middle of the 21st century as the demand for minerals is stimulated by the industrialization of poor countries, increasing urbanization, penetration of rapidly evolving high technologies, and the transition to low-carbon energies. In order to meet this demand, more metals will have to be produced by 2050 than over the last 100 years, which raises questions about the sustainability and conditions of supply. The answers to these questions are not only a matter of available reserves. Major effort will be required to develop new approaches and dynamic models to address social, economic, environmental, geological, technological, legal and geopolitical impacts of the need for resources.
DS1998-1144
1998
Vidal, P.Pedrosa-Soares, A.C., Vidal, P., Leondaros, O. Brito-.Neoproterozoic oceanic remnants in eastern Brasil: further evidence and refutation of exclusively ensialicGeology, Vol. 26, No. 6, June pp. 519-522.BrazilAracuai West Congo orogen, Craton - Sa Francisco, Congo
DS1985-0627
1985
Vidal, PH.Smith, D.C., Vidal, PH.Isotope Geochemistry and Geochronology of EclogitesChemical Geology, Isotope Geoscience Section., Vol. 52, No. 2, PP. 129-270.Norway, Italy, France, SpainEclogite, Geochronology, Geochemistry, Rare Earth Elements (ree), Zircon, U-pb, Nd, Rubidium-strontium (rb-sr)
DS1992-1180
1992
Vidal, Ph.Pedrosa-Soares, A.C., Noce, C.M., Vidal, Ph., Montero, R.L.B.P.Toward a new tectonic model for the Late Proterozoic Aracuai southeast Brasil-west Congolian southwest Africa beltJournal of South American Earth Sciences, Vol. 6, No. 1-2, pp. 33-47Brazil, Southwest AfricaTectonics, Proterozoic
DS1993-1319
1993
Vidal, Ph.Rohon, M.-L., Vialette, Y., Clar, T., Roger, G., Ohnenstetter, D., Vidal, Ph.Aphebian mafic-ultramafic magmatism in the Labrador trough (New Quebec):its age and the nature of its mantle source.Canadian Journal of Earth Sciences, Vol. 30, No. 8, August pp. 1582-1593.QuebecCrustal contamination, Ultramafics
DS1992-1605
1992
Vidale, J.E.Vidale, J.E., Benz, H.M.A sharp and flat section of the core-mantle boundaryNature, Vol. 359, No. 6396, October 15, pp. 627-629GlobalGeophysics, Mantle, Core-mantle
DS1992-1606
1992
Vidale, J.E.Vidale, J.E., Benz, H.M.Upper mantle seismic discontinuities and the thermal structure of subduction zonesNature, Vol. 356, No. 6371, April 23, pp. 678-682MantleDiscontinuity, Geophysics -seismics
DS1993-0107
1993
Vidale, J.E.Benz, H.M., Vidale, J.E.Probing the earth's interior using seismic arrays...brief overview forlaymanGeotimes, Vol. 38, No. 7, July pp. 20-22MantleGeophysics -seismics
DS1993-0108
1993
Vidale, J.E.Benz, H.M., Vidale, J.E.Sharpness of upper mantle discontinuities determined from high-frequencyreflectionsNature, Vol. 365, No. 6442, September 9, pp. 147-150MantleGeophysics -seismics, Discontinuity
DS1993-1664
1993
Vidale, J.E.Vidale, J.E., Benz, H.M.Seismological mapping of fine structure near the base of the earth'smantleNature, Vol. 361, No. 6412, Feb. 11, pp. 529-531GlobalGeophysics -seismics, Structure, Mantle
DS1993-1665
1993
Vidale, J.E.Vidale, J.E., Benz, H.M.Seimological mapping of the structure near the base of th earth's mantleNature, Vol. 361, No. 6412, Feb. 11, pp. 529-531.MantleGeophysics -seismics, Mantle
DS1994-0144
1994
Vidale, J.E.Benz, H.M., Vidale, J.E., Mori, J.Using regional seismic networks to study the earth's deep interiorEos, Vol. 75, No. 20, May 17, p. 225, 229.United StatesMantle tomography, Geophysics -seismics
DS1994-1853
1994
Vidale, J.E.Vidale, J.E.A mystery in the mantle... convective flow..Nature, Vol. 371, Sept. 22, p. 288.MantleGeophysics -seismics, Mantle flow
DS1994-1854
1994
Vidale, J.E.Vidale, J.E.A snapshot of whole mantle flowNature, Vol. 370, No. 6484, July 7, p. 16.MantleGeophysics, Fluidization
DS1995-1991
1995
Vidale, J.E.Vidale, J.E., et al.Sounding the base of the mantle by core relectionsEos, Vol. 76, No. 46, Nov. 7. p.F404. Abstract.MantleCore, Geophysics -seismic
DS1995-1992
1995
Vidale, J.E.Vidale, J.E., et al.The 410 km depth discontinuity: a sharpness estimate from near criticalreflections.Geophysical Research Letters, Vol. 22, No. 19, Oct. 1, pp. 2557-2560.MantleDiscontinuity
DS1998-1606
1998
Vidale, J.E.Xu, F., Vidale, J.E., Benz, H.M.Mantle discontinuities under southern Africa from precursors to P'P'dfGeophysical Research. Letters, Vol. 25, No. 4, Feb. 15, pp. 571-574.South Africa, southern AfricaGeophysics - discontinuity, Mantle
DS2001-1201
2001
Vidale, J.E.Vidale, J.E.Geophysics : peeling back the layers in the Earth's mantleScience, No. 5541, Oct. 12, pp. 313-4.MantleGeophysics - seismics
DS2001-1202
2001
Vidale, J.E.Vidale, J.E., SAchubert, G., Earle, P.S.Unsuccessful initial search for a midmantle chemical boundary with seismicarrays.Geophysical Research Letters, Vol. 28, No. 5, Mar. 1, pp. 859-62.MantleGeophysics - gravity, Geochemistry
DS2003-0969
2003
Vidale, J.E.Mooney, W.D., Vidale, J.E.Thermal and chemical variations in subcrustal cratonic lithosphere: evidence from crustalLithos, Vol. 71, 2-4, pp. 185-193.MantleGeothermometry, mineral chemistry
DS2003-1509
2003
Vidale, J.E.Xu, F., Vidale, J.E., Earle, P.S.Survey of precursors to P'P': fine structure of mantle discontinuitiesJournal of Geophysical Research, Vol. 08, 2, 10.1029/2001JB000817.MantleGeophysics - seismics, Discontinuity
DS200412-1357
2003
Vidale, J.E.Mooney, W.D., Vidale, J.E.Thermal and chemical variations in subcrustal cratonic lithosphere: evidence from crustal isostasy.Lithos, Vol. 71, 2-4, pp. 185-193.MantleGeothermometry, mineral chemistry
DS200412-2158
2003
Vidale, J.E.Xu, F., Vidale, J.E., Earle, P.S.Survey of precursors to P'P': fine structure of mantle discontinuities.Journal of Geophysical Research, Vol. 08, 2, 10.1029/2001 JB000817.MantleGeophysics - seismics Discontinuity
DS202204-0543
2022
Vidale, J.E.Wang, W., Vidale, J.E.An initial map of fine-scale heterogeneity in the Earth's inner core. *** not specific to diamondsNature Geoscience, Vol. 15, pp. 240-244.United States, Asia, South Americageophysics - seismics

Abstract: The seismological properties of Earth’s inner core are key to understanding its composition, dynamics and growth history. Within the inner core, fine-scale heterogeneity has previously been identified from backscattering of high-frequency compressional waves. Here we use historical earthquake and explosion data from the Large Aperture Seismic Array, USA, between 1969 and 1975 to build a 3D map of heterogeneity from the inner-core boundary to 500?km depth and determine the geographical distribution of the scatterers across the 40% of the inner core that is visible to the array. Our model has two regions of strong scattering, one beneath eastern Asia and the other beneath South America, both located where past local surveys have identified scattering. We suggest that these loci of strong, fine-scale heterogeneities may be related to random alignments of small, inner-core crystals due to fast freezing. These areas, which have been identified as having high attenuation and lie beneath colder areas of the core-mantle boundary, potentially provide constraints on the dynamics of the inner core and the motions in the outer core, with downwelling in the mantle and outer core possibly associated with strong scattering and inner-core heterogeneity.
DS1991-1798
1991
Videto, W.Videto, W.Crater of diamondsRock and GeM., Vol. 21, No. 4, April pp. 28-30ArkansasPopular geology, Brief overview
DS201610-1870
2016
Vidito, C.Herzberg, C., Vidito, C., Starkey, N.A.Nickel cobalt contents of olivine record origins of mantle peridotite and related rocks.American Mineralogist, Vol. 101, pp. 1952-1966.MantlePeridotite

Abstract: Olivine is distinguished from all other minerals in providing a remarkable chemical narrative about magmatic processes that occurred in Earth’s crust, mantle, and core over the entire age of Earth history. Olivines in mantle peridotite have Ni contents and Mg numbers that were largely produced by equilibrium crystallization in an early turbulently convecting magma ocean; subsequent stages of partial melting operated to slightly elevate Ni and Mg number in residual olivines. Olivines from Archean komatiites from the Abitibi greenstone belt have Ni contents and Mg numbers that are consistent with an extensively melted peridotite source at great depths in the mantle. Olivines from basaltic oceanic crust, the Icelandic mantle plume and other Phanerozoic occurrences have compositions that record magma chamber crystallization, recharge, mixing, and partial melting. Olivines from the present-day Icelandic mantle plume have compositions that are consistent the melting of a peridotite source; unlike Hawaii, the melting of recycled crust as a distinct pyroxenite lithology is not evident in the olivine chemistry of Iceland. Paleocene picrites from Baffin Island and West Greenland from the ancient Icelandic plume have olivines with Ni contents that are consistent with either Ni-rich peridotite that formed by core-mantle interaction or by low-pressure crystallization of hot and deep magmas. In general, hot magma oceans, mantle plumes, and ambient mantle magmatism form in ways that are captured by the compositions of the olivine crystals that they contain.
DS1998-1543
1998
Vidotti, R.M.Vidotti, R.M., Ebinger, C.J., Fairhead, J.D.Gravity signature of the western Parana basin, BrasilEarth and Plan. Sci. Lett, Vol. 159, pp. 117-32BrazilGeophysics - gravity, Bouguer, Flood basalts
DS202203-0340
2022
Vidotti, R.M.de Moura Almeida, Y., Marotta, G.S., Franca, G.S., Vidotti, R.M., Fuck, R.A.Crustal thickness estimation and tectonic analysis of the Amazonian craton from gravity data.Journal of South American Earth Sciences, Vol. 111, 10p. PdfSouth America, Brazilgeophysics - seismics

Abstract: The crustal thickness in South America has been mostly determined using seismological techniques. However, because these techniques provide point constraint or profile-specific results, the crustal thickness maps become especially dependent on both the number and spatial distribution of seismological stations. In the Amazonian Craton, the extensive forest cover restricts the number of existing stations, not allowing to elaborate a solely seismological crustal thickness model with homogeneous data coverage. Therefore, to overcome this difficulty, this work proposes a crustal thickness model for the Amazonian Craton developed based on the Parker-Oldenburg method and the Global Geopotential Model called GECO, considering the relationships between wavelengths and depths of the investigation sources. Furthermore, the developed iterative process allowed to determine the average depth of the crust-mantle interface, the density contrast at the interface, and the minimum and maximum frequencies used in the signal filtering process, making the model more robust for defining the used constants. The average crustal thickness of the Amazonian Craton was estimated as 40.25 km, with a standard deviation of the differences of 4.91 km, compared to crustal thickness defined by the seismological data. The estimated model shows great consistency with the data set used while allowing important inferences about craton compartmentation. Also, the geological provinces displayed an N-S connecting trend under the Amazonas, Solimões, and Acre basins, correlating the Guyana Shield with the Central Brazil Shield. Additionally, we observed various tectonic cycles acting on the craton while significantly modifying the structure of the provinces, possibly removing cratonic roots and rejuvenating the crust in older provinces.
DS202101-0008
2020
Viegas, A.Dessai, A.G., Viegas, A., Griffin, W.L.Thermal architecture of cratonic India and implications for decratonization of the western Dharwar craton: evidence from mantle xenoliths in the Deccan traps.Lithos, in press available, 56p. PdfIndiageothermometry

Abstract: The mantle beneath the Western Dharwar Craton of the Indian shield comprises a suite of refractory and fertile peridotites and mafic granulites. Detailed petrographic studies coupled with new mineral analysis and geothermobarometric estimations permit to decipher the thermal architecture and get an insight into the evolution of this ancient craton. The refractory rocks are coarse grained harzburgites/dunites, whereas the more fertile ones are at times, porphyroclastic lherzolites. Both show a similar range of equilibration temperatures and pressures indicating intermixing between the two at various levels. The peridotites contain undeformed interstitial REE-enriched clinopyroxene, phlogopite, apatite and carbonates recording post-kinematic modal and cryptic metasomatic events in the Precambrian cratonic lithosphere. Xenoliths of mafic granulite contain layers of clinopyroxenite which also vein the granulite. The P-T range of the granulites overlaps that of the ultramafic rocks. This study in combination with previous investigations reveals a distinct change in the thermal architecture of the craton from a warm/hot geotherm in the Proterozoic to a highly perturbed, still hotter geotherm of the Palaeocene. The Cenozoic thermotectonic rifting episodes heated, refertilized and thinned the bulk of the cratonic lithosphere beneath the Western Dharwar Craton, which has witnessed the most re-activation among cratons of the Indian shield. The waning of the Deccan Traps volcanism in Palaeocene time saw the reworking of ancient cratonic lithosphere and its replacement by non-cratonic, juvenile mantle and magmatic accretions, indicated by compound xenoliths. Differing petrological and geochemical characteristics of refractory xenoliths and fertile lherzolites serve to constrain the relative timing and composition of non-cratonic lithosphere. By the end of the Palaeocene the Western Dharwar Craton was characterised by a thermal high, an attenuated continental lithosphere (60-80 km), and a thin crust (<10- ~ 21 km), reflecting the decratonization of at least the western part of the Western Dharwar Craton.
DS201612-2285
2016
Viegas, G.Cavalcante, G.C.C., Viegas, G., Archanjo, C.J.The influence of partial melting and melt migration on the rheology of the continental crust.Journal of Geodynamics, Vol. 101, pp. 186-199.MantleMelting

Abstract: The presence of melt during deformation produces a drastic change in the rheological behavior of the continental crust; rock strength is decreased even for melt fractions as low as ?7%. At pressure/temperature conditions typical of the middle to lower crust, melt-bearing systems may play a critical role in the process of strain localization and in the overall strength of the continental lithosphere. In this contribution we focus on the role and dynamics of melt flow in two different mid-crustal settings formed during the Brasiliano orogeny: (i) a large-scale anatectic layer in an orthogonal collision belt, represented by the Carlos Chagas anatexite in southeastern Brazil, and (ii) a strike-slip setting, in which the Espinho Branco anatexite in the Patos shear zone (northeast Brazil) serves as an analogue. Both settings, located in eastern Brazil, are part of the Neoproterozoic tectonics that resulted in widespread partial melting, shear zone development and the exhumation of middle to lower crustal layers. These layers consist of compositionally heterogeneous anatexites, with variable former melt fractions and leucosome structures. The leucosomes usually form thick interconnected networks of magma that reflect a high melt content (>30%) during deformation. From a comparison of previous work based on detailed petrostructural and AMS studies of the anatexites exposed in these areas, we discuss the rheological implications caused by the accumulation of a large volume of melt “trapped” in mid-crustal levels, and by the efficient melt extraction along steep shear zones. Our analyses suggest that rocks undergoing partial melting along shear settings exhibit layers with contrasting competence, implying successive periods of weakening and strengthening. In contrast, regions where a large amount of magma accumulates lack clear evidence of competence contrast between layers, indicating that they experienced only one major stage of dramatic strength drop. This comparative analysis also suggests that the middle part of both belts contained large volumes of migmatites, attesting that the orogenic root was partially molten and encompassed more than 30% of granitic melt at the time of deformation.
DS201012-0153
2010
Viegas, S.Dessai, A.G., Viegas, S.Petrogenesis of alkaline rocks from Murudjanjira, in the Deccan traps, western India.Mineralogy and Petrology, Vol. 98, 1-4, pp. 297-311.IndiaAlkalic
DS1990-1256
1990
Viehweg, M.Rollig, G., Viehweg, M., Reuter, N.The ultramafic lamprophyres and carbonatites of Delitzsch/GDR. (in German)Zeitschrift fur Angewandte Geologie, (in German), Vol. 36, No. 2, February pp. 49-53GermanyCarbonatite
DS201903-0548
2019
Vieira Conceicao, R.Vieira Conceicao, R., Colombo Carniel, L., Jalowitski, T., Gervasoni, F., Grings Cedeno, D.Geochemistry and geodynamic implications on the source of Parana-Etendeka Large Igneous Province evidenced by the late 128 Ma Rosario-6 kimberlite, southern Brazil.Lithos, Vol. 328-329, pp. 130-145.South America, Brazildeposit - Rosario-6

Abstract: The Rosário-6 is a non-diamondiferous hypabyssal kimberlite located above the Rio de la Plata craton and near the south-eastern edge of the Paraná Basin, in southern Brazil. It is petrographically an inequigranular texture, macrocrystal kimberlite, fresh and the groundmass exhibits a microporphyritic texture and round megacrysts of olivine, which are derived from disaggregated mantle xenoliths. Olivine is also present as macrocrysts, microphenocrysts and in the groundmass together with phlogopite and apatite. These microphenocrysts are immersed in a groundmass of olivine, monticellite, phlogopite, CaTiO3-perovskite, apatite, Mg-chromite and Mg-ulvöspinel and melilite. A mesostasis assemblage of phlogopite, melilite, soda melilite, akermanite and calcium carbonate is segregated from the groundmass. Its geochemical signature is similar to those of transitional kimberlites of Kaapvaal Craton, South Africa, and the U-Pb ages of ~ 128 Ma on perovskite reveal that Rosário-6 kimberlite post-dates the main pulse of volcanism in the Paraná-Etendeka Large Igneous Province (LIP). The high Ti content of some minerals, such as Mg-chromite, Mg-ulvöspinel, phlogopite and melilite, and the presence of perovskite suggest a Ti-rich source. The petrographic, geochemical and isotopic data indicate that the Rosário-6 kimberlite source is a depleted mantle metasomatized by H2O-rich fluids, CO2-rich and silicate melts derived from the recycling of an ancient subducted oceanic plate (eclogite) before the South Atlantic opening. Although several authors indicate the influence of Tristan da Cunha plume for the generation of alkaline magmatism associated to the Paraná-Etendeka flood basalts, our data demonstrates that Tristan da Cunha plume has no chemical contribution to the generation of Rosário-6 kimberlite, except by its thermal influence.
DS201112-0253
2010
Vieira de Almeida, V.De Assis Janasi, V., Andrade, S., Svisero, D.P.,Vieira de Almeida, V.Inferencias sobre a evolucao petrologica do manto no sudeste brasileiro a partir de microanalises de elementos traco em piroxenios e olivin a de xenolitos de espinelio peridotitos.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 85.South America, BrazilPetrology of pyroxenes, olivines in xenoliths
DS1999-0771
1999
Viejo, G.F.Viejo, G.F., Clowes, R.M., Amor, J.R.Imaging the lithospheric mantle in northwestern Canada with seismic wide angle reflections.Geophysical Research. Lett., Vol. 26, No. 18, Sept. 15, pp. 2809-12.Saskatchewan, Manitoba, Alberta, Northwest TerritoriesGeophysics - seismics, Lithosphere
DS1975-1254
1979
Viele, G.W.Viele, G.W.Geological Map and Cross Section, Eastern Ouachita Mountains,arkansaw.Geological Society of America., No. MC 28F, 7P.United States, Oklahoma, ArkansasBlank
DS1982-0261
1982
Viele, G.W.Hatcher, R.D.JR., Viele, G.W.The Appalachian/ouachita Orogens: United States and MexicoIn: Perspectives On Regional Geological Synthesis, Planning, D-NAG No. 1, PP. 67-75.GlobalMid-continent, Carolina Slate Belt
DS1982-0619
1982
Viele, G.W.Viele, G.W.Interpretation of Aeromagnetic Anomalies South Central United States.Geological Society of America (GSA), Vol. 14, No. 7, P. 638, (abstract.).GlobalMid-continent, Geophysics
DS1983-0617
1983
Viele, G.W.Viele, G.W.Collision Effects on the Craton Caused by the Ouachita Orogeny.Geological Society of America (GSA), Vol. 15, No. 6, P. 712. (abstract.).GlobalMid Continent
DS1984-0363
1984
Viele, G.W.Houseknecht, D.W., Viele, G.W.Early Palaeozoic Tectonic and Sedimentary History of the Northern Mississippi Embayment.Geological Society of America (GSA), Vol. 16, No. 3, P. 146. (abstract.).GlobalMid-continent
DS1992-0060
1992
Viele, G.W.Babaei, A., Viele, G.W.Two decked nature of the Ouachita Mountains, ArkansawGeology, Vol. 20, No. 11, November pp. 995-998ArkansasStructure, Ouachita Mountains - general
DS200512-0156
2005
Vielma, P.Channer, D., Graffe, E., Vielma, P.Geology, mining and mineral potential of southern Venezuela. Diamonds pp. 19-20. Guaniamo area.SEG Newsletter, No. 62, July, pp. 5,13-23.South America, VenezuelaHistory, geology
DS2002-1665
2002
Vielreicher, N.M.Vielreicher, N.M., Ridley, J.R., Groves, D.I.Marymia: an Archean, amphibolite facies hosted orogenic lode gold deposit overprinted by Paleoproterozoic....Mineralium Deposita, Vol.AustraliaMetallogeny - base metal mineralization, Deposit - Marymia
DS1984-0422
1984
Vielzeuf, D.Kornprobst, J., Vielzeuf, D.Transcurrent Crustal Thinning: a Mechanism for the Uplift Of Deep Continental Crust/upper Mantle Associations.Proceedings of Third International Kimberlite Conference, Vol. 2, PP. 347-359.GlobalPetrology, Ultramafic, Granulites
DS1988-0732
1988
Vielzeuf, D.Vielzeuf, D.Granulites and their problemsTerra Cognita, Eclogite conference, Vol. 8, No. 3, Summer, pp. 237-239. plus abstractsGlobalGranulites, Eclogites
DS1992-1184
1992
Vielzeuf, D.Perkins, D., Vielzeuf, D.Experimental investigation of iron-magnesium distribution between olivine andclinopyroxene:mixing properties of iron-magnesium in clinopyroxene, garnet-clinopyroxenetherM.American Mineralogist, Vol. 77, No. 7, 8 July-August pp. 774-783GlobalClinopyroxene, Experimental petrology -garnet
DS1992-1185
1992
Vielzeuf, D.Perkins, D., Vielzeuf, D.Experimental investigation of iron, magnesium distribution between olivine and clinopyroxene: implications for mixing properties of iron and magnesium...American Mineralogist, Vol. 77, pp. 774-83.MantleThermometry - garnet clinopyroxene
DS1995-0885
1995
Vielzeuf, D.Jianping, L., Kornprobst, J., Vielzeuf, D.An improved experimental calibration of the olivine spinel geothermometerChinese Journal of Geochemistry, Vol. 14, No. 1, pp. 68-77.GlobalGeothermometry, Olivine -spinel calibration
DS200612-0059
2006
Vielzeuf, D.Auzanneau, E., Vielzeuf, D., Schmidt, M.W.Experimental evidence of decompression melting exhumation of subducted continental crust.Contributions to Mineralogy and Petrology, Vol. 152, 2, pp. 125-148.MantleSubduction
DS201012-0027
2009
Vielzeuf, D.Auzanneau, E., Schmidt, M.W., Vielzeuf, D., Connolly, J.A.D.Titanium in phengite: a geobarometer for high temperature eclogites.Contributions to Mineralogy and Petrology, Vol. 159, 1, pp. 1-24.MantleGeothermometry
DS200612-0060
2006
Vielzeuf, E.Auzanneau, E., Vielzeuf, E., Schmidt, M.W.Experimental evidence of decompression melting during exhumation of subducted continental crust.Contributions to Mineralogy and Petrology, Vol. 152, 2, pp. 125-148.MantleSubduction
DS1986-0381
1986
Vienna AustriaInternational Atomic Energy Agency, Vienna AustriaCorrelation of uranium geology between South America and Africa, mapsInternational Atomic Energy Agency (I.A.E.A.), 4 maps. Map 1 Precambrian cratonic areas and mobile beGlobalMap 4 Alkaline complexes and kimberlites, Map 2 Paleozoic and Gondwana sequences Map 3 Post Gondw
DS1860-0326
1879
Viennot, T.C.Viennot, T.C.Le Diamant (1879)Soc. Linneenne Department Maine Et Loire Annual, Vol. 17, PP. 100-155.Europe, Spain, England, IrelandGemology
DS1998-1027
1998
Viera, I.S.Mohriak, W.U., Bassetto, M., Viera, I.S.Crustal architecture and tectonic evolution of the Sergipe Alagoas and Jacuipe basins, offshore northeast BrasilTectonophysics, Vol. 288, No. 1-4, Mar. pp. 199-220BrazilTectonics, Basins - offshore
DS1984-0749
1984
Viereck, L.Viereck, L.Geologic and Petrologic Development of the Rieden Pleistocene Volcanic Complex, Eastern Eifel.Bochumer Geol. U Geotech. Arbeiten., Vol. 17, 377P.West GermanyLeucitite, Petrography, Mineral Chemistry
DS1985-0592
1985
Viereck, L.Schmicke, H.U., Mertes, H., Viereck, L.Mafic Magmas from the Quaternary Eifel Volcanic FieldsConference Report of The Meeting of The Volcanics Studies Gr, 1P. ABSTRACT.GermanyNephelinite, Melilite
DS200812-0001
2008
Viererck-Goette, L.Abrates, M., Viererck-Goette, L., Ulyych, J., Munsel, D.Melilitic rocks of the CECIP examples from Vogtland W. Bohemia.Goldschmidt Conference 2008, Abstract p.A2.Europe, Germany, Czech RepublicMelilitite
DS202202-0191
2022
Vierira Conceicao, R.Ferreira, A.C.D., Vierira Conceicao, R., Pimentel Mizusaki, A.M. Mesozoic to Cenozoic alkaline and tholeiitic magmatism related to West Gondwana break up and dispersal of south American kimberlites.Gondwana Research, Vol. 106, pp. 15-33. pdfSouth Americacraton - Amazon

Abstract: For over 50 years, Mesozoic tholeiites, kimberlites and carbonatites from the South American platform have been enabled the understanding of melting processes in the Earth’s upper mantle. However, the genetic relationship between alkaline and tholeiitic magmatism remains unknown. In this context, an extensive review, based on a compilation of published geochemical and isotopic data, shows an integrated evolution for mantle-derived magmatism in South America. The K-rich alkaline-carbonatite intrusions occur widespread through time at 255-209 Ma, 146-106 Ma and 91-71 Ma. Moreover, the Na-rich magmatic episodes are also documented at 130-120 Ma and 66-32 Ma. Tholeiitic basaltic lavas and dikes are recorded at ?200 Ma in Northern Brazil and mainly between 134 and 131 Ma in the Paraná Magmatic Province. Simultaneous tholeiitic lavas and carbonatitic complexes are related to near isothermal decompression of enriched asthenospheric and lithospheric mantle sources at different depths (80-200 km). Likewise, the 267-226 Ma kimberlites in the Amazonian Craton, ?128 Ma Rosário kimberlite in the Rio de la Plata Craton and 88-80 Ma Alto Paranaíba kimberlites in the western edge of the São Francisco Craton provide evidence for deeper (>200 km) metasomatized mantle sources. Compiled numerical, geophysical and geological data support the proposal that the thickness of the lithosphere, extension rates and the presence of previous weak crustal structures contributed to the generation and emplacement of multiple tholeiitic and alkaline intrusions from 250 to 30 Ma. We propose that several crustal extension events induced repeated thermal convection cells in the metasomatized asthenosphere, which triggered partial melting in the previously enriched and heterogeneous lithospheric mantle. The local mantle composition, depth and crustal extension ratios controlled the magma composition. Thus, West Gondwana break-up and dispersal played a crucial role in the Mesozoic to Paleogene melting processes of the metasomatized mantle in South America.
DS201909-2031
2019
Vierire Conceicao, R.Colombo, C.L., Vierire Conceicao, R., Grings, C.D.Implications for mantle heterogeneity and diamond preservation derived from RosaRio-6 kimberlite, south of Brazil.Goldschmidt2019, 1p. Poster abstractSouth America, Brazildeposit - RosaRio-6
DS1996-1207
1996
Viero, P.Roisenberg, A., Viero, P.The relationships between alkaline Mesozoic magmatism -transform faults in Rio Grande de Sul and Santa CatarinaInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 392.BrazilLamproites, Dikes
DS1960-0196
1961
Vierthaler, A.A.Vierthaler, A.A.Wisconsin Diamonds #2Gems And Gemology, Vol. 10, No. 7, PP. 210-215.United States, Great Lakes, WisconsinDiamond Occurrence
DS1960-0197
1961
Vierthaler, A.A.Vierthaler, A.A.There Are Diamonds in WisconsinLapidary Journal, Vol. 15, No. 1, P. 18; P. 20; P. 22; P. 26.United States, Great Lakes, WisconsinDiamond Occurrence, History, Crystallography, Morphology
DS201112-1090
2011
Viet Anh, T.Viet Anh, T., Pang, K-N., Chung, S-L., Lin, H-M., Trong Hoa, T.The Song Da magmatic suite revisited: a petrologic, geochemical and Sr Nd isotopic study on picrites, flood basalts and silicic volcanic rocks.Journal of Asian Earth Sciences, Vol. 42, 6, pp. 1341-1355.ChinaPlume lithosphere interaction, ELIP
DS201909-2046
2019
Viete, D.R.Holder, R.M., Viete, D.R., Brown, M., Johnson, T.E.Metamorphism and the evolution of plate tectonics.Nature, doi.org/10.1038/ s41586-019-1462-2 2p.Mantleplate tectonics

Abstract: Earth’s mantle convection, which facilitates planetary heat loss, is manifested at the surface as present-day plate tectonics1. When plate tectonics emerged and how it has evolved through time are two of the most fundamental and challenging questions in Earth science1,2,3,4. Metamorphic rocks—rocks that have experienced solid-state mineral transformations due to changes in pressure (P) and temperature (T)—record periods of burial, heating, exhumation and cooling that reflect the tectonic environments in which they formed5,6. Changes in the global distribution of metamorphic (P, T) conditions in the continental crust through time might therefore reflect the secular evolution of Earth’s tectonic processes. On modern Earth, convergent plate margins are characterized by metamorphic rocks that show a bimodal distribution of apparent thermal gradients (temperature change with depth; parameterized here as metamorphic T/P) in the form of paired metamorphic belts5, which is attributed to metamorphism near (low T/P) and away from (high T/P) subduction zones5,6. Here we show that Earth’s modern plate tectonic regime has developed gradually with secular cooling of the mantle since the Neoarchaean era, 2.5 billion years ago. We evaluate the emergence of bimodal metamorphism (as a proxy for secular change in plate tectonics) using a statistical evaluation of the distributions of metamorphic T/P through time. We find that the distribution of metamorphic T/P has gradually become wider and more distinctly bimodal from the Neoarchaean era to the present day, and the average metamorphic T/P has decreased since the Palaeoproterozoic era. Our results contrast with studies that inferred an abrupt transition in tectonic style in the Neoproterozoic era (about 0.7 billion years ago1,7,8) or that suggested that modern plate tectonics has operated since the Palaeoproterozoic era (about two billion years ago9,10,11,12) at the latest.
DS201910-2265
2019
Viete, D.R.Holder, R., Viete, D.R., Brown, M., Johnson, T.E.Metamorphism and evolution of plate tectonics.Nature, Vol. 572, 7769, pp. 1-4.Mantleplate tectonics

Abstract: Earth’s mantle convection, which facilitates planetary heat loss, is manifested at the surface as present-day plate tectonics1. When plate tectonics emerged and how it has evolved through time are two of the most fundamental and challenging questions in Earth science1,2,3,4. Metamorphic rocks—rocks that have experienced solid-state mineral transformations due to changes in pressure (P) and temperature (T)—record periods of burial, heating, exhumation and cooling that reflect the tectonic environments in which they formed5,6. Changes in the global distribution of metamorphic (P, T) conditions in the continental crust through time might therefore reflect the secular evolution of Earth’s tectonic processes. On modern Earth, convergent plate margins are characterized by metamorphic rocks that show a bimodal distribution of apparent thermal gradients (temperature change with depth; parameterized here as metamorphic T/P) in the form of paired metamorphic belts5, which is attributed to metamorphism near (low T/P) and away from (high T/P) subduction zones5,6. Here we show that Earth’s modern plate tectonic regime has developed gradually with secular cooling of the mantle since the Neoarchaean era, 2.5 billion years ago. We evaluate the emergence of bimodal metamorphism (as a proxy for secular change in plate tectonics) using a statistical evaluation of the distributions of metamorphic T/P through time. We find that the distribution of metamorphic T/P has gradually become wider and more distinctly bimodal from the Neoarchaean era to the present day, and the average metamorphic T/P has decreased since the Palaeoproterozoic era. Our results contrast with studies that inferred an abrupt transition in tectonic style in the Neoproterozoic era (about 0.7 billion years ago1,7,8) or that suggested that modern plate tectonics has operated since the Palaeoproterozoic era (about two billion years ago9,10,11,12) at the latest.
DS200512-1102
2004
Vietor, T.Trumbull, R.B., Vietor, T., Hahne, K., Wackerle, R., Ledru, P.Aeromagnetic mapping and reconnaissance geochemistry of the Early Cretaceous Henties Bay Outjo dike swarm, Etendeka Igneous Province, Namibia.Journal of African Earth Sciences, Vol. 40, 1-2, Sept. pp. 17-29.Africa, NamibiaGeophysics - magnetics, basaltic dikes, geochemistry
DS201807-1534
2018
Vietti, A.J.Vietti, A.J.A strategy for improving water recovery in kimberlitic diamond mines. TSF VlariVie44 dosingSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 247-258.Globalwater - TSF

Abstract: Presentation: http://www.saimm.co.za/Conferences/Diamonds2018/P247-Vietti.pdf
DS201904-0796
2019
Vietti, A.J.Vietti, A.J.A strategy for improving water recovery in kimberlitic diamond mines.The Southern African Institute of Mining and Metallurgy, Vol. 119, pp. 165-171.Africa, South Africawater - diamond mining
DS1960-0411
1963
Viewing, K.A.Viewing, K.A.Regional Geochemical Patterns Related to Mineralization in Central sierra Leone.London: Ph.d. Thesis, University London., 325P.Sierra Leone, West AfricaGeochemistry, Kimberlite, Diamond, Sula, Kangari
DS1960-0719
1966
Viewing, K.D.Nicol, I., James, L.D., Viewing, K.D.Regional Geochemical Reconnaissance in Sierra LeoneInstitute of Mining and Metallurgy. Transactions, Vol. 75, PP. B146-161.Sierra Leone, West AfricaGeochemistry, Kimberlite, Diamonds
DS201608-1449
2016
Viezzoli, A.Viezzoli, A., Kaminski, V.Airborne IP: examples from the Mount Milligan deposit Canada, and the Amakinskaya kimberlite pipe, Russia.Exploration Geophysics , http://dx.doi.org/10.1071/EG16015 10p. AvailableRussiaDeposit Amakinskaya, Geophysics

Abstract: There have been multiple occurrences in the literature in the past several years of what has been referred to as the induced polarisation (IP) effect in airborne time domain electromagnetic (TDEM) data. This phenomenon is known to be responsible for incorrect inversion modelling of electrical resistivity, lower interpreted depth of investigation (DOI) and lost information about chargeability of the subsurface and other valuable parameters. Historically, there have been many suggestions to account for the IP effect using the Cole-Cole model. It has been previously demonstrated that the Cole-Cole model can be effective in modelling synthetic TDEM transients. In the current paper we show the possibility of extracting IP information from airborne TDEM data using this same concept, including inverse modelling of chargeability from TDEM data collected by VTEM, with field examples from Canada (Mt Milligan deposit) and Russia (Amakinskaya kimberlite pipe).
DS201610-1858
2016
Viezzoli, A.Di Massa, D., Kaminski, V., Viezzoli, A.Airborne IP: Drybones kimberlite VTEM dat a Cole-Cole inversion.ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 4p.Canada, Northwest TerritoriesDeposit - Drybones

Abstract: A VTEM survey was flown over the Drybones kimberlite in 2005, followed by a ZTEM survey in 2009. These data sets were inverted on multiple previous occasions using various 1D, 2D, 3D and plate modelling algorithms. VTEM data showed AIP effects, manifested as negative voltages and otherwise skewed transients. This created artefacts in conventional inversions of VTEM data, which showed some inconsistencies with ZTEM inversions, as well as with the known geology. In 2015 the VTEM data were transferred to Aarhus Geophysics, reprocessed and reinverted using the modified "AarhusINV" code with Cole-Cole modelling. The results are presented in current abstract, they appear to be more interpretable and provide better data fit, than previous inversion attempts.
DS201703-0411
2017
Viezzoli, A.Kaminski, V., Viezzoli, A.Modeling induced polarization effects in helicopter time domain electromagnetic data: Field case studies ( Drybones Bay, NWT)Geophysics, Vol. 82, 2, pp. B49-B61.Canada, Northwest TerritoriesGeophysics, deposit - Drybones

Abstract: Induced polarization (IP) effects are becoming more evident in time-domain helicopter airborne electromagnetic (AEM) data thanks to advances in instrumentation, mainly due to improvements in the signal-to-noise ratio and hence better data quality. Although the IP effects are often manifested as negative receiver voltage values, which are easy to detect, in some cases, IP effects can distort recovered transients in other ways so they may be less obvious and require careful data analysis and processing. These effects represent a challenge for modeling and inversion of the AEM data. For proper modeling of electromagnetic transients, the chargeability of the subsurface and other parameters describing the dispersion also need to be taken into consideration. We use the Cole-Cole model to characterize the dispersion and for modeling of the IP effects in field AEM data, collected by different airborne systems over different geologies and exploration targets, including examples from diamond, gold, and base metal exploration.
DS201703-0437
2017
Viezzoli, A.Viezzoli, A., Kaminskiy, V., Fiandaca, G.Modeling induced polarization effects in helicopter time domain electromagnetic data: synthetic case studies. ( kimberlite simulated)Geophysics, Vol. 82, 2, pp. E31-E50.TechnologyGeophysics - IP, EM

Abstract: We have developed a synthetic multiparametric modeling and inversion exercise undertaken to study the robustness of inverting airborne time-domain electromagnetic (TDEM) data to extract Cole-Cole parameters. The following issues were addressed: nonuniqueness, ill posedness, dependency on manual processing and the effect of constraints, and a priori information. We have used a 1D layered earth model approximation and lateral constraints. Synthetic simulations were performed for several models and the corresponding Cole-Cole parameters. The possibility to recover these models by means of laterally constrained multiparametric inversion was evaluated, including recovery of chargeability distributions from shallow and deep targets based on analysis of induced polarization (IP) effects, simulated in airborne TDEM data. Different scenarios were studied, including chargeable targets associated with the conductive and resistive environments. In particular, four generic models were considered for the exercise: a sulfide model, a kimberlite model, and two generic models focusing on the depth of investigation.
DS201705-0886
2016
Viezzoli, A.Viezzoli, A.Tli Kwi Cho shootout. IV GeophysicsSEG Annual Meeting Dallas, 67 ppt.Canada, Northwest TerritoriesDeposit - Tli Kwi Cho
DS201809-2015
2018
Viezzoli, A.Di Massa, D., Fedi, M., Florio, G., Vitale, A., Viezzoli, A., Kaminski, V.Joint interpretation of AEM and aeromagnetic dat a acquired over the Drybones kimberlite, NWT ( Canada).Journal of Applied Physics, Vol. 158, pp. 48-56.Canada, Northwest Territoriesdeposit - Drybones

Abstract: We present the joint interpretation of airborne electromagnetic and aeromagnetic data, acquired to study kimberlite pipes. We analyse the data surveyed in 2005 over Drybones Bay, Archean Slave Province of the Northwest Territories, northern Canada. This area hosts a recently discovered kimberlite province with >150 kimberlite pipes. Magnetic and electromagnetic data were each one modelled by 1D inversion. For magnetic data we inverted vertical soundings built through upward continuations of the measured data at various altitudes. The validity of the method was prior verified by tests on synthetic data. Electromagnetic data were processed and inverted using the modified AarhusINV code, with Cole-Cole modelling, in order to take into account induced polarization effects, consisting in negative voltages and otherwise skewed transients. The integrated study of the two kinds of data has led to a better understanding of the structures at depth, even though the comparison between the magnetic and the electromagnetic models shows the different sensitivity of the two methods with respect to the geological structure at Drybones Bay.
DS1990-1518
1990
Vigasina, M.F.Vigasina, M.F., Orlov, R.Yu.Raman microprobing of stishovite and lonsdeiliteInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 478-479RussiaMicroscopy, Lonsdeilite
DS1993-1666
1993
Vigasina, M.F.Vigasina, M.F.Dynamics of the crystal lattice of lonsdaliteDoklady Academy of Sciences USSR, Earth Science Section, Vol. 317, No. 5, pp. 188-190.Russia, Commonwealth of Independent States (CIS)Diamond, Mineralogy
DS201901-0050
2018
Vigasina, M.F.Ogorodova, L.P., Gritsenko, Y.D., Vigasina, M.F., Bychkov, A.Y., Ksenofontov, D.A., Melchakova, L.V.Thermodynamic properties of natural melilites.American Mineralogist, Vol. 103, pp. 1945-1952.Mantlemineralogy

Abstract: In the present study, four samples of natural melilites were characterized using electron microprobe analysis, powder X-ray diffraction, FTIR, and Raman spectroscopy, and their thermodynamic properties were measured with a high-temperature heat-flux Tian-Calvet microcalorimeter. The enthalpies of formation from the elements were determined to be: -3796.3 ± 4.1 kJ/mol for Ca1.8Na0.2(Mg0.7Al0.2Fe2+0.1?)Si2O7, -3753.6 ± 5.2 kJ/mol for Ca1.6Na0.4(Mg0.5Al0.4Fe2+0.1?)Si2O7, -3736.4 ± 3.7 kJ/mol for Ca1.6Na0.4(Mg0.4Al0.4Fe2+0.2?)Si2O7, and -3929.2 ± 3.8 kJ/mol for Ca2(Mg0.4Al0.6)[Si1.4Al0.6O7]. Using the obtained formation enthalpies and estimated entropies, the standard Gibbs free energies of formation of these melilites were calculated. Finally, the enthalpies of the formation of the end-members of the isomorphic åkermanite-gehlenite and åkermanite-alumoåkermanite series were derived. The obtained thermodynamic properties of melilites of different compositions can be used for quantitative modeling of formation conditions of these minerals in related geological and industrial processes.
DS201112-1091
2011
Vigeresse, J.L.Vigeresse, J.L., Chattaraj, P.K.Describing the chemical character of a magma.Chemical Geology, Vol. 287, 1-2, pp. 102-113.MantleChemistry - magma
DS201412-0889
2014
Vigier, N.Su, B-X., Zhang, H-F., Deloule, E., Vigier, N., Hu, Y., Tang, H-J., Xiao, Y., Sakyi, P.A.Distinguishing silicate and carbonatite mantle metasomatism by using lithium and its isotopes.Chemical Geology, Vol. 381, pp. 67-77.ChinaXenoliths - Hannuoba
DS1991-1799
1991
Vigneresse, J.L.Vigneresse, J.L., Cuney, M.What can we learn about crustal structure from thermal data?Terra Nova, Vol. 3, No. 2, pp. 28-34GlobalGeothermometry, Remote sensing
DS1998-0335
1998
Vigneresse, J.L.Dehls, J.F., Cruden, A.R., Vigneresse, J.L.Fracture control of late Archean pluton emplacement in the northern SlaveProvince.Journal of Structural Geology, Vol. 20, No. 9/10, Sept. pp. 1145-54.Northwest TerritoriesTectonics, structure, Not specific to diamonds
DS1989-1271
1989
Vigny, C.Rickard, Y., Vigny, C.Mantle dynamics with induced plate tectonicsJournal of Geophysical Research, Vol. 94, No. B 12, December 10, pp. 17, 523-17, 542GlobalMantle, Tectonics
DS1991-1800
1991
Vigny, C.Vigny, C., Ricard, Y., Froidevaux, C.The driving mechanism of plate tectonicsTectonophysics, Vol. 187, pp. 345-360GlobalTectonics, Plate tectonics - mechanisms
DS1995-1993
1995
Vijaka Kumar, K.Vijaka Kumar, K., Ratnakar, J.The gabbros of Prakassam alkaline province, Andhra Pradesh, IndiaJournal of Geological Society India, Vol. 46, No. 3, Sept. pp. 245-254.IndiaAlkaline rocks
DS201312-0737
2012
Vijaya Rao, V.Reddy, P.R., Vijaya Rao, V.Seismic images of the continental Moho of the Indian shield.Tectonophysics, Vol. 609, pp. 217-233.IndiaGeophysics - seismics
DS1994-0213
1994
Vijoen, D.Broome, J., Vijoen, D.CD ROM distribution of intergrated geoscience dat a sets for the NATMAP shield margin project area, Manitoba and Saskatchewan.Geological Survey of Canada Open Forum January 17-19th. Abstracts only, p. 12.Manitoba, SaskatchewanGIS, Craton
DS200412-0797
2004
Vijoen, D.Harris, J.R., Vijoen, D., Bonham-Carter, G.F., Brown, N.Dispersal train identification algorthim (DTIA).Geological Survey of Canada, Open File 4672, 1 CD $ 20.00TechnologyComputer - geochemistry .. not specific to diamonds
DS200412-1806
2003
Vijoen, F.Shirey, S.B., Harris, J.W., Richardson, S.H.,Fouch, M., James, D.E., Cartigny, P.,Deines, P., Vijoen, F.Regional patterns in the paragenesis and age of inclusions in diamond, diamond composition and the lithospheric seismic structurLithos, Vol. 71, 2-4, pp. 243-258.Africa, South AfricaDiamond inclusions
DS201212-0317
2012
Vijoen, F.Huizenga,J.M., Crossingham, A., Vijoen, F.Diamond precipitation from ascending reduced fluids in the Kaapvaal lithosphere: thermodynamic constraints.Comptes Rendus Geoscience, Vol. 344, pp. 67-76.Africa, South AfricaRedox melting
DS2002-0084
2002
Vijoen, K.Aulbach, S., Stachel, T., Vijoen, K., Brey, G., HarrisEclogitic and websteritic diamond sources beneath the Limpopo Belt - is slab melting the link?Contribution to Mineralogy and Petrology, Vol.143, 1, Feb.pp.56-70.South AfricaDiamond - inclusions, mineralogy, Secondary Ion Mass Spectrometry, Deposit - Venetia
DS1995-1778
1995
Vijoen, K.S.Smith, C.B., Shulze, D.J., Bell, D., Vijoen, K.S.Bearing of the subcalcic chromium poor megacryst suite on kimberlite petrogenesis and lithospheric structure.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 546-548.South AfricaMegacrysts, Deposit -Kaalvallei, Frank Smith, Lace
DS200412-1905
2004
Vijoen, K.S.Stachel, T., Aulbach, S., Brey, G.P., Harris, J.W., Leost, I., Tappert, R., Vijoen, K.S.The trace element composition of silicate inclusions in diamonds: a review.Lithos, Vol. 77, 1-4, Sept. pp. 1-19.MantleDiamond inclusion, REE, metasomatism, lithosphere, garn
DS200412-1912
2004
Vijoen, K.S.Stachel, T., Vijoen, K.S., McDada, P., Harris, J.W.Survival of diamonds during major tectonothermal events - peridotitic inclusions in diamonds from Orapa and Jwaneng.Geological Association of Canada Abstract Volume, May 12-14, SS14-13 p. 272.abstractAfrica, BotswanaGeochemistry - major element
DS200412-2059
2004
Vijoen, K.S.Vijoen, K.S., Dobbe, R., Smit, B., Thomassot, E., Cartigny, P.Petrology and geochemistry of a Diamondiferous lherzolite from the Premier diamond mine, South Africa.Lithos, Vol. 77, 1-4, Sept. pp. 539-552.Africa, South AfricaPeridotite, infrared analysis, nitrogen, diamond morpho
DS201604-0592
2016
Vijoen, K.S.Aulbach, S., Gerdes, A., Vijoen, K.S.Formation of Diamondiferous kyanite eclogite in a subduction melange.Geochimica et Cosmochimica Acta, Vol. 179, pp. 156-176.Africa, South AfricaDeposit - Lace

Abstract: Diamond- and kyanite-bearing eclogites from the Lace kimberlite on the Kaapvaal craton have common picritic to gabbroic oceanic protoliths with bimineralic eclogites, lying on arrays of Eu? and ?REE that are consistent with accumulation and fractionation of plagioclase and olivine. However, they also show significant compositional differences, such as more grossular-rich garnet and aluminous clinopyroxene (cpx), which require the operation of additional processes. Their nature is elucidated using mineral major- and trace-element compositions, as well as Sr isotope ratios determined by in situ techniques.Highly variable major-element compositions across the co-genetic eclogite suites exert a strong effect on the trace-element distribution between garnet and cpx, whereby Sc, Ge, Sr, Y, Cd, REE, Th and U partition more strongly into garnet with increasing grossular-content. Thus, significant differences between the trace-element compositions of garnet can ensue from crystal-chemical effects alone, making their use as petrogenetic indicators potentially ambiguous. After correcting for these compositional effects, garnet in kyanite-/diamond eclogites, and in eclogites devoid of accessory minerals but with similar signatures, shows depletion (or dilution) in Sc, Ge, Y, In, Zr, Hf and the HREE, and enrichment in the LREE and Th compared to garnet in bimineralic eclogites. This is interpreted as the signature of a pelite-derived melt, which was transferred by addition of aluminous cpx that later exsolved kyanite and garnet, as observed in other aluminous eclogite suites. Continental input can explain initial (at 2.9 Ga) 87Sr/86Sr ? 0.714 measured in cpx in eleven samples with low 87Rb/86Sr (<0.01). The association of diamond with kyanite suggests that diamond formation is also linked to this event, possibly due to diamond formation by oxidation of reduced carbon, such as methane, and attendant reduction of Fe3+ in garnet. This model of sediment melt-oceanic crust interaction reconciles evidence for both low- and high-pressure igneous processes in some aluminous eclogites. We suggest that a subduction mélange is a favourable setting for the transfer of a sediment-derived signature into oceanic crust, leading to formation of diamondiferous kyanite-eclogites from bimineralic eclogites. Diapirism, fluxed by the presence of partial melt, may have facilitated dispersal of the eclogites in the lithosphere column, consistent with their widely varying equilibration pressures ranging from ?5 to 8 GPa.
DS200712-0966
2007
Viktoorv, M.A.Serov, R.S., Viktoorv, M.A.Features of low temperature optical spectra of natural and treated diamonds.Moscow University Geology Bulletin, Vol. 62, 2, Mar-April pp. 127-TechnologyDiamond morphology
DS2002-1666
2002
Viktorov, M.A.Viktorov, M.A., Shelementiev, Yu.B., Saparin, G.V., Obyden, S.K., ChhukichevSpectroscopic properties of artifically coloured diamonds18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.149.GlobalDiamond - colouration
DS200612-1480
2005
Viktorov, M.A.Viktorov, M.A., Kopchikov, M.B.Proton irradiation of natural and synthetic diamonds.Moscow University Geology Bulletin, Vol. 60, 5, pp. 62-75.TechnologyDiamond irradiation
DS200612-1481
2005
Viktorov, M.A.Viktorov, M.A., Kopchikov, M.B.Proton irradiation of natural and synthetic diamonds.Moscow University Geology Bulletin, Vol. 60, 5. pp. 62-75.TechnologyDiamond morphology
DS201012-0683
2007
Viktorov, M.A.Serov, R.S., Viktorov, M.A.Diagnostics of natural and synthetic diamonds with the aid of low temperature optical spectroscopy.Moscow University Geology Bulletin, Vol. 62, pp. 46-48.TechnologySpectroscopy
DS1985-0699
1985
Vila, V.Vila, V.New Apparatus for Identification of Diamond; Bgi Diamond Tester.*spaGemologia (Barcelona) *SPA., Vol. 17, No. 55-56, pp. 57-69GlobalDiamond Morphology
DS201801-0076
2017
Viladakar, S.G.Viladakar, S.G.Pyroxene sovite in Amba Dongar carbonatite-alkalic complex, Gujarat.Journal of the Geological Society of India, Vol. 90, 5, pp. 591-594.Indiacarbonatite

Abstract: The present paper for the first times gives details of pyroxenesövites of Amba Dongar and discusses significance of these pyroxenes in evolution of carbonatite magma in Amba Dongar. Calciocarbonatite (sövite) forms the major mass of carbonatite in Amba Dongar complex. It shows large variation in texture and mineral composition and has complex evolutionary history. Three types of compositional variations are observed in sövite samples, (1) monomineralic sövites are coarse grained with 99% calcite, (2) sövites with abundant apatite, barite, pyrochlore, magnetite and zirconolite and (3) silico-sövite with of clinopyroxene and phlogopite. In the crystallization history of various sövite types, silico-sövite seems to have crystallized as an earlier phase and was later caught up in major sövite mass. Both, phlogopite-sövite and pyroxene-sövite are coarse grained and exhibit hypidiomorphic texture. Phlogopite is strongly zoned with Mg-rich core to Fe-rich rims. Pyroxenes also exhibit zoning with decrease in Ca and Mg and increase in Fe and Na from core to rim. In general composition of clinopyroxene varies from diopsidic to aegirine-augite. Pyroxenesövites show good concentration of Ba, Sr, Nb and LREE. Elevated concentrations of LREE are found in two aegirine-sövites.
DS202102-0204
2020
Viladar, S.Magna, T., Viladar, S., Rapprich, V., Pour, O., Hopp, J., Cejkova, B.Nb-V enriched sovites of the northeastern and eastern part of the Amba Dongar carbonatite ring dike, India - a reflection of post-emplacement hydrothermal overprint?Geochemistry, Vol. 80, doi.org/10.1016 /j.chemer.2019 .125534 11p. PdfIndiadeposit - Amba Dongar

Abstract: Wakefieldite-(Ce,La) and vanadinite in coarse-grained calciocarbonatites (sovites) are for the first time reported from the northeastern part of the worldwide largest fluorite deposit at the Amba Dongar carbonatite ring dike, India. Sovite in this part of the carbonatite ring dike is rich in pyrochlore, calcite and magnetite. Pyrochlore makes up almost 50% of some sovite samples and shows core-to-rim compositional changes. The core of pyrochlore consists of primary fluorcalciopyrochlore with high F and Na contents while the margins gained elevated amounts of Pb, La and Ce with the associated loss of F and Na due to circulation of hydrothermal solutions. The presence of wakefieldite-(Ce,La) and vanadinite points to an exceptionally high V abundance in hydrothermal solutions formed towards the end of the carbonatite magma activity. This investigation thus opens new promising areas for Nb and REE prospection in the eastern part of the Amba Dongar carbonatite body.
DS201012-0168
2009
Viladar, S.G.Doroshkevich, A.G., Viladar, S.G., Ripp, G.S., Burtseva, M.V.Hydrothermal REE mineralization in the Amba Dongar carbonatite complex, Gujarat, India.Canadian Mineralogist, Vol. 47, 5, pp. 1105-1116.IndiaCarbonatite
DS201412-0948
2014
Viladar, S.G.Viladar, S.G., Bismayer, U.U rich pyrochlore from Sevathur carbonatites, Tamil Nadu.Journal of the Geological Society of India, Vol. 83, Feb. pp. 175-182.IndiaCarbonatite
DS201803-0437
2018
Viladar, S.G.Chandra, J., Paul, D., Viladar, S.G., Sensarma, S.Origin of Amba Dongar carbonatite complex, India and its possible linkage with the Deccan Large Igneous Province.Geological Society of London Special Publication, No. 463, pp. 137-169.Indiacarbonatite

Abstract: The genetic connection between Large Igneous Province (LIP) and carbonatite is controversial. Here, we present new major and trace element data for carbonatites, nephelinites and Deccan basalts from Amba Dongar in western India, and probe the linkage between carbonatite and the Deccan LIP. Carbonatites are classified into calciocarbonatite (CaO, 39.5-55.9 wt%; BaO, 0.02-3.41 wt%; ?REE, 1025-12 317 ppm) and ferrocarbonatite (CaO, 15.6-31 wt%; BaO, 0.3-7 wt%; ?REE, 6839-31 117 ppm). Primitive-mantle-normalized trace element patterns of carbonatites show distinct negative Ti, Zr-Hf, Pb, K and U anomalies, similar to that observed in carbonatites globally. Chondrite-normalized REE patterns reveal high LREE/HREE fractionation; average (La/Yb)N values of 175 in carbonatites and approximately 50 in nephelinites suggest very-low-degree melting of the source. Trace element modelling indicates the possibility of primary carbonatite melt generated from a subcontinental lithospheric mantle (SCLM) source, although it does not explain the entire range of trace element enrichment observed in the Amba Dongar carbonatites. We suggest that CO2-rich fluids and heat from the Deccan plume contributed towards metasomatism of the SCLM source. Melting of this SCLM generated primary carbonated silicate magma that underwent liquid immiscibility at crustal depths, forming two compositionally distinct carbonatite and nephelinite magmas.
DS202105-0763
2021
Viladar, S.G.Fosu, B.R., Ghosh, P., Weisenberger, T.B., Spurgin, S., Viladar, S.G.A triple oxygen isotope perspective on the origin, evolution, and diagenetic alteration of carbonatites.Geochimica et Cosmochimica Acta, Vol. 299, pp. 52-68. pdfMantlecarbonatites

Abstract: Carbonatites are unique magmatic rocks that are essentially composed of carbonates, and they usually host a diverse suite of minor and accessory minerals. To provide additional insights on their petrogenesis, triple oxygen isotope analyses were carried out on carbonatites from sixteen localities worldwide in order to assess the behaviour of oxygen isotopes (mass-dependent fractionation) during their formation. The study evaluates the mineralogical differences, i.e., calcite, dolomite, ankerite, and Na-carbonates, and the mode of emplacement (intrusive or extrusive) in the mantle-derived carbonatites to further constrain the triple oxygen isotopic composition (??17O) of the upper mantle. ??17O values in the intrusive calcite carbonatites vary between ?0.003 to ?0.088‰ (n?=?20) and ?0.024 to ?0.085‰ (n?=?5) in the dolomite varieties. We surmise that the magnitude of isotopic fractionation in the different carbonate phases during their formation is similar and thus, the observed variations are independent of mineralogy and may be related to alteration in the rocks. Taking the samples that classify as primary igneous carbonatites altogether, the average ??17O value of the mantle is estimated as ?0.047?±?0.027‰ (1SD, n?=?18) which overlaps those of other mantle rocks, minerals and xenoliths, indicating that the mantle has a relatively homogenous oxygen isotope composition. Two ankerite carbonatites have identical ??17O values as calcite but a few samples, together with pyroclastic tuffs have significantly lower ??17O values (?0.108 to ?0.161‰). This deviation from mantle ??17O signature suggests diagenetic alteration (dissolution and recrystallisation) and mixing of carbonate sources (juvenile and secondary carbonates) which is consistent with the high ?18O and clumped isotope (?47) values recorded in the pyroclastic and ankeritic rocks. In summary, diagenetic alteration driven by fluid-rock interaction at low temperatures, sub-solidus re-equilibration with magmatic waters, and the incorporation of secondary carbonates altogether facilitate the alteration of original isotopic compositions of carbonatites, obliterating their primary mantle signatures.
DS200912-0184
2009
Viladkar, S.Doroshkevich, A.G., Ripp, G., Viladkar, S.Newania carbonatites, western India: example of mantle derived magnesium carbonatites.Mineralogy and Petrology, in press availableIndiaCarbonatite
DS201911-2543
2019
Viladkar, S.Magna, T., Viladkar, S., Rappirich, V., Pour, O., Cejkova, B.Nb-V enriched sovites of the northeastern and eastern part of the Amba Dongar carbonatite ring dike, India - a reflection of post emplacement hydrothermal overprint.Chemie der Erde, in press available 11p. Indiadeposit - Amba Dongar
DS1981-0419
1981
Viladkar, S.G.Viladkar, S.G.The Carbonatites of Amba Dongar, Gujarat IndiaGeological Society FINLAND Bulletin., Vol. 53, No. 1, PP. 17-28.India, GujaratBlank
DS1985-0700
1985
Viladkar, S.G.Viladkar, S.G.Alkaline rocks associated with the carbonatites of Amba Donger, Chhota Udaipur Gujarat IndiaIndian Mineralogist, Sukheswala Volume, pp. 130-135IndiaCarbonatite
DS1985-0701
1985
Viladkar, S.G.Viladkar, S.G.Alkaline rocks associated with the carbonatites of Amba Dongar Udaipur Gujarat IndiaIndian Minerals, Sukhneswala special volume, pp. 130-135IndiaCarbonatite
DS1986-0835
1986
Viladkar, S.G.Viladkar, S.G., Duliski, P.Rare earth element abundances in carbonatites, alkaline rock sand fenites of the Amba Dungar Complex Gujarst India.Neues Jahrbuch f?r Mineralogie Petrol, No. 1, January pp. 37-48IndiaRare earth, Alkaline rocks
DS1986-0836
1986
Viladkar, S.G.Viladkar, S.G., Wimmenauer, W.Mineralogy and geochemistry of the Newania carbonatite fenite complex Rajasthan IndiaNeues Jahrb. fur Mineralogie abhand, Vol. 156, No. 1, pp. 1-21IndiaBlank
DS1988-0676
1988
Viladkar, S.G.Sukheswala, R.N., Avasia, R.K., Viladkar, S.G., Gwalani, L.G.Deccan basalts associated with carbonatite volcanism, ChhotaUdaipurGujarat, IndiaV.m. Goldschmidt Conference, Program And Abstract Volume, Held May, p. 76. AbstractIndiaCarbonatite
DS1991-1801
1991
Viladkar, S.G.Viladkar, S.G.Phlogopitization at Amba Dongar carbonatite alkalic omplex, IndiaNeues Jhrb. Min, Ser. A, Vol. 162, No. 2, January pp. 201-213IndiaCarbonatite, Petrology
DS1993-1667
1993
Viladkar, S.G.Viladkar, S.G., Kienast, J.R., Fourcade, S.Mineralogy of the Newania carbonatites Rajasthan, IndiaTerra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 55.IndiaCarbonatite, Mineralogy
DS1994-1855
1994
Viladkar, S.G.Viladkar, S.G.Economic geology of Amba Dongar (Eocene) and Newania (Proterozoic)carbonatites, India.9th. IAGOD held Beijing, Aug.12-18., p. 692. abstractIndiaCarbonatite
DS1994-1856
1994
Viladkar, S.G.Viladkar, S.G., Scleicher, H., Pawaskar, P.Mineralogy and geochemistry of the Sung Valley carbonatite complex, Shillong, Meghalaya, India.Neues Jahrbuch f?r Mineralogie, No. 11, pp. 499-517.IndiaCarbonatite, Deposit - Sung Valley
DS1995-1761
1995
Viladkar, S.G.Simonetti, A., Bell, K., Viladkar, S.G.Isotopic dat a from the Amba Donga carbonatite Complex, west-central India:evidence for enriched mantle sourceChemical Geology, Vol. 122, pp. 185-198.IndiaCarbonatite, geochronology, Deposit -Amba Donga
DS1996-1479
1996
Viladkar, S.G.Viladkar, S.G., Simonetti, A.Amba Dongar sub-volcanic diatreme: a review of field, petrological and geochemical aspects.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 400.IndiaCarbonatite, Deposit -Amba Dongar
DS1997-1210
1997
Viladkar, S.G.Viladkar, S.G.Petrology of the Siriwasan carbonatite alkalic complex Chhota Udaipur, Bujarat India.Geological Association of Canada (GAC) Abstracts, POSTER.IndiaCarbonatite
DS1998-1292
1998
Viladkar, S.G.Schleicher, H., Kramm, U., Viladkar, S.G.Enriched subcontinental Upper Mantle beneath southern India: evidence from lead neodymium Sr Co isotopic studies...Journal of Petrology, Vol. 39, No. 10, Oct. pp. 1765-86.IndiaCarbonatite, geochronology, Deposit - Tamil Nadu
DS1998-1544
1998
Viladkar, S.G.Viladkar, S.G.Carbonatite occurrences in Rajasthan, IndiaPetrology, Vol. 6, No. 3, June, pp. 252-273.IndiaCarbonatite
DS200512-1140
2001
Viladkar, S.G.Viladkar, S.G.Carbonatites of India: an overview.Alkaline Magmatism and the problems of mantle sources, pp. 257-271.IndiaCarbonatite
DS200512-1141
2005
Viladkar, S.G.Viladkar, S.G., Ramesh, R., Avasia, R.K., Pawaskar, P.B.Extrusive phase of carbonatite alkalic activity in Amba Dongar Complex, Chhota Udaipur Gujarat.Journal of the Geological Society of India, Vol. 66, 3, pp. 273-276.IndiaCarbonatite
DS200512-1149
2003
Viladkar, S.G.Vladykin, N.V., Viladkar, S.G., Miyazaki, T., Ram Mohan, V.Chemical composition of carbonatites of Tamil Nadu massif ( South India) and problem of benstoonite carbonatites.Plumes and problems of deep sources of alkaline magmatism, pp. 130-154.IndiaCarbonatite, geochemistry
DS200812-0034
2008
Viladkar, S.G.Andreasen, R., Sharma, M., Subbarao, K.V., Viladkar, S.G.Where on Earth is the enriched Hadean reservoir.Earth and Planetary Science Letters, Vol. 266, 1-2, pp. 14-28.MantleGeochronology
DS200812-0295
2008
Viladkar, S.G.Doroshkevich, A.G., Ripp, G.S., Viladkar, S.G., Vladykin, N.V.The Arshan REE carbonatites, southwestern Transbaiklia, Russia: mineralogy, parageneis, and evolution.Canadian Mineralogist, Vol. 46, 4, August pp.RussiaCarbonatite
DS201012-0818
2010
Viladkar, S.G.Viladkar, S.G.Evolution of carbonatite dykes in Amba Dongar carbonatite Alkalic ring complex, Gujarat India.International Dyke Conference Held Feb. 6, India, 1p. AbstractIndiaCarbonatite
DS201012-0819
2010
Viladkar, S.G.Viladkar, S.G.The origin of pseudoleucite in tinguaite, Ghori, India: a re-evaluation.Petrology, Vol. 18, 5, pp. 544-554.IndiaLeucite
DS201112-0102
2011
Viladkar, S.G.Boz, D.M., Schulzki, J., Viladkar, S.G.Selected accessory minerals and their alteration types in the carbonatite breccias of the Amba Dongar diatreme.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterIndiaCarbonatite
DS201112-0103
2011
Viladkar, S.G.Boz, D.M., Schulzki, J., Viladkar, S.G.Selected accessory minerals and their alteration types in the carbonatite breccia of the Amba Dongar diatreme.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.10.IndiaSovite
DS201112-0104
2011
Viladkar, S.G.Boz, D.M., Schulzki, J., Viladkar, S.G.Selected accessory minerals and their alteration types in the carbonatite breccia of the Amba Dongar diatreme.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.10.IndiaSovite
DS201312-0114
2013
Viladkar, S.G.Burtseva, M.V., Ripp, G.S., Doroshkevich, A.G., Viladkar, S.G., Varadan, R.Features of mineral and chemical composition of the Khamambettu carbonatites, Tamil, Nadu.Journal of the Geological Society of India, Vol. 81, 5, pp. 655-664.IndiaCarbonatite
DS201607-1318
2016
Viladkar, S.G.Viladkar, S.G., Gittins, J.Trace element and REE geochemistry of Siriwasan carbonatite, Chhota Udaipur, Gujarat.Journal of the Geological Society of India, Vol. 87, 6, pp. 709-715.IndiaCarbonatite

Abstract: The Siriwasan carbonatite-sill along with associated alkaline rocks and fenites is located about 10 km north of the well-known Amba Dongar carbonatite-alkaline rocks diatreme, in the Chhota Udaipur carbonatite-alkaline province. Carbonatite has intruded as a sill into the Bagh sandstone and overlying Deccan basalt. This resulted in the formation of carbonatite breccia with enclosed fragments of basement metamorphics, sandstone and fenites in the matrix of ankeritic carbonatite. The most significant are the plugs of sovite with varied mineralogy that include pyroxene, amphibole, apatite, pyrochlore, perovskite and sphene. REE in sovites is related to the content of pyrochlore, perovskite and apatite. The carbon and oxygen isotopic compositions of some sovite samples and an ankeritic carbonatite plot in the "mantle box" pointing to their mantle origin. However, there is also evidence for mixing of the erupting carbonatite magma with the overlying Bagh limestone. The carbonatites of Siriwasan and Amba Dongar have the same Sr and Nd isotopic ratios and radiometric age, suggesting the same magma source. On the basis of available chemical analyses this paper is aimed to give some details of the Siriwasan carbonatites. The carbonatite complex has good potential for an economic mineral deposit but this is the most neglected carbonatite of the Chhota Udaipur province.
DS201801-0004
2017
Viladkar, S.G.Benjamin, F.R., Ghosh, P., Viladkar, S.G.A secular variation of stable isotope record in global carbonatite magma.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p.11.Globalcarbonatites

Abstract: Carbonatites are magmatic rocks, origin of these relates to the involvement of mantle fluid. Thus they provide indirect method to understand the sub-continental upper mantle fluid composition. The first report on carbonatites and the later eruption of the natrocarbonatite paved way for investigating the heterogeneity of the mantle with depth and since then, many other occurrences have been found worldwide, offering suitable samples for probing the mantle. We present record of stable isotopic composition of carbonatites spanning Precambrian, Proterozoic to Phanerozoic to Recent time based on their temporal occurrences and global distribution in the geological record. We consider the various tectonic settings from which carbonatites have been reported, the underlying eruption mechanisms taking into account the tectonic significance of their occurrence and their imprints on surrounding rocks. This account covers carbonatites and associated rocks from different continents with a prime focus on carbon and oxygen isotopes. Carbon and oxygen isotope composition vary significantly within time spans. These variations depend on other factors besides mantle composition i.e. carbonate mineralogy and alteration processes that can cause a shift from original compositions. We envisage the use of stable isotope records to address the secular variation of crustal mixing / contamination process in geological time. Many of these secular variation are abrupt and probably indicate shift in the tectonic forcing - a vital factor responsible for driving the secular trend.
DS201801-0023
2017
Viladkar, S.G.Hopp, J., Viladkar, S.G.Noble gas composition of Indian carbonatites ( Amba Dongar, Siriwasan): implications on mantle source compositions and late stage hydrothermal processes.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 10.Indiadeposit - Amba Dongar, Siriwasan

Abstract: Within a stepwise crushing study we determined the noble gas composition of several calcite separates, one aegirine and one pyrochlore-aegirine separate of the carbonatite ring dyke complex of Amba Dongar and carbonatite sill complex of Siriwasan, India. Both carbonatites are related to the waning stages of volcanic activity of the Deccan Igneous Province ca. 65 Ma ago. Major observations are a clear radiogenic 4He* and nucleogenic 21Ne* imprint related to insitu production from U and Th in mineral impurities, most likely minute apatite grains. However, in first crushing steps of most calcites from Amba Dongar a well-resolvable mantle neon signal is observed, with lowest air-corrected mantle 21Ne/22Ne-compositions equivalent to the Réunion hotspot mantle source. In case of the aegirine separate from Siriwasan we found a neon composition similar to the Loihi hotspot mantle source. We conclude that previously derived models of a lithospheric mantle source containing recycled components in generation of the carbonatitic magmas from Amba Dongar are obsolete. Instead, the mantle source of both investigated carbonatite complexes is related to a primitive mantle plume source that we tentatively ascribe to the postulated Deccan mantle plume. If, as is commonly suggested, the present location of the Deccan mantle plume source is below Réunion Island, the currently observed more nucleogenic neon isotopic composition of the Réunion hotspot might be obliterated by significant upper mantle contributions, similar to Kilauea Volcano, Hawai’i. In addition, compared with other carbonatite complexes worldwide a rather significant contribution of atmospheric noble gases is observed. This is documented in cut-off 20Ne/22Ne-ratios of ca. 10.2 (Amba Dongar) and 10.45 (Siriwasan) and cut-off 40Ar/36Ar-ratios of about 1500. This atmospheric component likely had been added at shallow levels during the emplacement process. However, understanding the late-stage interaction between atmospheric gases and magmatic mantle fluids still requires further investigation.
DS201801-0026
2017
Viladkar, S.G.Jadhav, G.N., Viladkar, S.G., Goswami, R., Badhe, K.Fluid melt inclusions petrography of primary calcites from carbonatites of Amba Dongar, Gujarat India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 15.Indiadeposit - Amba Dongar

Abstract: The Amba Dongar Carbonatite complex consists of sovites which are dominantly composed of calcite along with pyrochlore, phlogopite, apatite, barite, ankerite and haematite and minor opaques such as magnetite, chalcopyrite and pyrite. Two distinct types of texture are present in these carbonatites- a mosaic of equigranular calcite crystals and porphyritic texture. Silicate melt inclusions are observed in primary minerals viz. apatite and calcites. These are small droplets of silicate melt entrapped during the growth of the minerals. In this case carbonatite-alkaline silicate melt inclusions are entrapped predominantly in calcite crystals. Dominantly these calcite host minerals are predominantly containing fluid inclusions along with halite, sylvite and minor nahcolite as daughter crystals. The presence of calcite with nahcolite indicates the coexistence of a Ca-rich, alkali-bearing carbonatite melt phase. The melt inclusions are heated upto 1100 °C and the carbonate melt inclusions appear to be homogenized around 950 °C. This fall within the range of melting temperature of a carbonatite melt. In addition to these, three types of fluid inclusions were also observed in host calcite they are i) monophase, ii) biphase and iii) polyphase types of fluid inclusions. The fluid inclusions contain CO2 gas, Li-K carbonate phases and fergusonite based on Micro-Laser- Raman. Carbon dioxide is the dominant gas phase in most of the fluid inclusions, indicating high temperature and deep mantle source(?). The fluid inclusions have formed from a primary mother liquor that has separated out from the early formed carbonatitic melt. This fluid was either formed just after the formation of melt inclusions or during simultaneous crystallization from a carbonatitic or to be more precise carbonatiticpegmatite melt(?).The presence of both melt and fluid inclusions in these primary calcite host minerals indicates the presence of a carbonatitic-pegmatitic fluid, which must have got separated out from the early formed carbonatite-alkaline silicate magma.
DS201801-0056
2017
Viladkar, S.G.Schulzki, J., Viladkar, S.G., Schleicher, H.Carbonatite breccia: a neglected unit in Amba Dongar distreme, Gujarat, India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 38.Indiadeposit - Amba Dongar

Abstract: Carbonatite breccia forms a major unit in the carbonatite-alkalic diatreme of Amba Dongar. In addition to the innermost part of the ring structure, it also forms small and large plugs outside ring structure in form of discontinuous ring around sövite. It is mainly composed of rounded to sub-angular fragments of basement metamorphics, Bagh sandstones, pre-carbonatite basalt, nephelinite and sövite set in the carbonatitic matrix. Besides rock fragments it also shows presence xenocrystal minerals. Carbonatite breccia is later invaded by sövite, alvikite and ankeritic carbonatite. Thorite, pyrochlore, barite, apatite, fluorite and small amount of REE-minerals were introduced in carbonatite breccia by these later intrusives. Zircon, however seems have been caught up from metamorphic gneisses. Microprobe analyses of all these minerals are given here. In places, carbonatite breccia has been silicified by invading hydrothermal solutions rich in fluorite and silica.
DS201801-0062
2017
Viladkar, S.G.Shitole, A., Sant, D.A., Parvez, I.A., Rangarajan, G., Patel, S., Viladkar, S.G., Murty, A.S.N., Kumari, G.Shallow seismic studies along Amba Dongar to Sinhada ( longitude 74 3 50E) transect, western India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 16.Indiadeposit - Amba Dongar

Abstract: The microtremor method is applied to map subsurface rheological boundaries (stratigraphic, faults and plutons) is based on strong acoustic impedance across contrasting density of rock/ sediment/ weathered interfaces up to shallow depths along longitude 74° 3'50" E from village Amba Dongar (latitude: 21° 59'N) up to Sinhada village (latitude: 22° 14' N). The 30 km long transect exposes variety of rocks viz., unclassified granite gneisses and metasediments (Precambrian age); sediments belonging to Bagh Group (Late Cretaceous); alkaline - carbonatite plutons and lava flows belonging to Deccan Traps (Late Cretaceous). In all, sixty stations were surveyed along the longitude 74° 3'50" E with spacing of 500 m. H/V spectral ratio technique reveals four rheological interfaces identified by resonant frequencies (fr) ranges 0.2213 to 0.7456 Hz (L1), 1.0102 to 3.076 Hz (L2), 4.8508 to 21.0502 Hz (L3), and 24.5018 to 27.1119 Hz (L4). L1 represents interface between plutons, Precambrian basement rocks; L2 represents interface between Bagh sediments, Deccan Traps and intrusives whereas L3 and L4 captures depth of top most weathered profile. We estimate the depth range for L1 L2 L3 and L4 using equation (h = 110.18fr?1.97) derived based on Deep Banni Core (1764 m deep from surface: DGH record). Deep Banni Core has a distinct interface between Mesozoic rocks and Precambrian basement. The depths are further compared with terrain-based equation. Further, the overall results from the present study are compared with seismic refraction studies along Phangia-Kadipani (NGRI Technical Report, 2003). The subsurface profile across longitude 74° 3'50" E educe faults that bound Bagh Group of rocks with Deccan Trap and Precambrian. We identify two plutons underneath three zones of intrusive viz., Amba Dongar Carbonatite Complex (Station 1 to 8), Tiloda Alkaline (station 33 to 44) and Rumadia Alkaline (station 46 to 51). The present study demarcates the presence of depression over Amba Dongar hill (station 1 to 3), filled by post carbonatite basalt earlier reported by Viladkar et al., (1996 and 2005) suggesting caldera morphology. Similarly, studies identify intrusive-pluton interfaces one, below the Amba Dongar hill, and second between village Tiloda and Rumadia at depth of ~500 m from the surface. Microtremor survey further depicts both basement morphology and thickness of Bagh Group and Deccan Traps.
DS201801-0064
2017
Viladkar, S.G.Simon, S.J., Wei, C.T., Viladkar, S.G., Ellmies, R., Soh, Tamech, L.S., Yang, H., Vatuva, A.Metamitic U rich pyrochlore from Epembe sovitic carbonatite dyke, NW Namibia.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 12.Africa, Namibiadeposit - Epembe

Abstract: The Epembe carbonatite dyke is located about 80 km north of Opuwo, NW Namibia. The 10 km long dyke is dominated by massive and banded sövitic carbonatite intrusions. Two distinct type of sövite have been recognized: (1) coarse-grained light grey Sövite I which is predominant in brecciated areas and (2) medium- to fine-grained Sövite II which hosts notable concentrations of pyrochlore and apatite. The contact between the carbonatite and basement gneisses is marked by K-feldspar fenite. The pyrochlore chemistry at Epembe shows a compositional trend from primary magmatic Ca-rich pyrochlore toward late hydrothermal fluid enriched carbonatite phase, giving rise to a remarkable shift in chemical composition and invasion of elements such as Si, U, Sr, Ba, Th and Fe. Enrichment in elements like U, Sr and Th lead to metamictization, alteration and A-site vacancy. It is therefore suggested that the carbonatite successive intrusive phases assimilated primary pyrochlore leading to extreme compositional variation especially around the rims of the pyrochlore. The genesis of the Epembe niobium deposit is linked to the carbonatite magmatism but the mechanism that manifested such niobium rich rock remains unclear and might be formed as a result of cumulate process and/or liquid immiscibility of a carbonate-silicate pair.
DS201805-0951
2018
Viladkar, S.G.Hopp, J., Viladkar, S.G.Noble gas composition of Indian carbonatites ( Amba Dongar, Siriwasan): implications on mantle source compositions and late stage hydrothermal processes.Earth Planetary Science Letters, Vol. 492, pp. 186-196.Indiacarbonatite

Abstract: Within a stepwise crushing study we determined the noble gas composition of several calcite separates, one aegirine and one pyrochlore-aegirine separate of the carbonatite ring dyke complex of Amba Dongar and carbonatite sill complex of Siriwasan, India. Both carbonatites are related to the waning stages of volcanic activity of the Deccan Igneous Province ca. 65 Ma ago. Major observations are a clear radiogenic 4He and nucleogenic 21Ne imprint related to in situ production from U and Th in mineral impurities, most likely minute apatite grains, or late incorporation of crustal fluids. However, in first crushing steps of most calcites from Amba Dongar a well-resolvable mantle neon signal is observed, with lowest air-corrected mantle 21Ne/22Ne-compositions equivalent to the Réunion hotspot mantle source. In case of the aegirine separate from Siriwasan we found a neon composition similar to the Loihi hotspot mantle source. This transition from a mantle plume signal in first crushing step to a more nucleogenic signature with progressive crushing indicates the presence of an external (crustal) or in situ nucleogenic component unrelated and superposed to the initial mantle neon component whose composition is best approximated by results of first crushing step(s). This contradicts previous models of a lithospheric mantle source of the carbonatitic magmas from Amba Dongar containing recycled crustal components which base on nucleogenic neon compositions. Instead, the mantle source of both investigated carbonatite complexes is related to a primitive mantle plume source that we tentatively ascribe to the postulated Deccan mantle plume. If, as is commonly suggested, the present location of the Deccan mantle plume source is below Réunion Island, the currently observed more nucleogenic neon isotopic composition of the Réunion hotspot might be obliterated by significant upper mantle contributions. In addition, compared with other carbonatite complexes worldwide a rather significant contribution of atmospheric noble gases is observed. This is documented in cut-off 20Ne/22Ne-ratios of ca. 10.2 (Amba Dongar) and 10.45 (Siriwasan) and cut-off 40Ar/36Ar-ratios of about 1500. This atmospheric component had been added at shallow levels during the emplacement process or later during hydrothermal alteration. However, understanding the late-stage interaction between atmospheric gases and magmatic mantle fluids still requires further investigation.
DS201810-2388
2018
Viladkar, S.G.Viladkar, S.G.Ferrocarbonatites in the Amba Dongar diatreme, Gujarat, India.Journal of the Geological Society of India, Vol. 92, 2, pp. 141-144.Indiadeposit - Amba Dongar

Abstract: In the Amba Dongar diatreme, "ferrocarbonatite" is not a single unit of late differentiate of calciocarbonatite magma but it is a family with variation on field occurrence, mineralogy and chemistry of each unit. The family includes dikes of ankeritic carbonatites (phase I and II), plugs of ankeritic carbonatite within sövite ring dike, dikes of sideritic carbonatite in ankeritic carbonatite plug and rödberg veins. Their intrusive relations are very clear in the field and each phase has characteristic mineralogy and trace and REE geochemistry. According to the nomenclature suggested by Harmer and Gittins (1997) majority of "ferrocarbonatites" of Amba Dongar plot in field of "ferruginous calciocarbonatite" and only siderite and rödberg plot in the field of "ferrocarbonatite". Within these family members, their trace and REE show clear increase from early phase to last phase of sideritic carbonatite. The present short communication discusses various aspects of "ferrocarbonatites".
DS202004-0511
2020
Viladkar, S.G.Fosu, B.R., Ghosh, P., Viladkar, S.G.Clumped isotope geochemistry of carbonatites in the north-western Deccan igneous province: aspects of evolution, post-depositional alteration and mineralization.Geochimica et Cosmochimica Acta, Vol. 274, pp. 118-135.Indiacarbonatite

Abstract: Carbonatites crystallise along a wide range of solidus temperatures and are commonly affected by post-magmatic textural re-equilibration and diagenesis. Further insights into the formation and modification of carbonatites are provided using carbon, oxygen and clumped isotope (?47) data of rocks from spatially associated Amba Dongar and Siriwasan alkaline complexes in the north-western Deccan igneous province, India. We derive apparent equilibrium blocking temperatures to help constrain the thermal evolution of the different rock types found within the alkaline complexes in a petrographic context. The apparent temperatures for the carbonatites are significantly low but are consistent with reports on other global carbonatites and model predictions. Rapidly cooled Oldoinyo Lengai natrocarbonatite yielded similar low temperatures, even in the absence of bulk isotopic alteration. The isotopic proxies and petrographic observations favour both isotopic exchange reactions and diagenesis in altering ?47 values in calciocarbonatites. Diagenetic reactions are however strongly favoured, as secondary calcites in nephelinites and ferrocarbonatites record much lower temperatures than in the calciocarbonatites, highlighting the effect of fluids and diagenetic reactions in 13C18O bond ordering in carbonatites. Variations in the CO isotope data reveal the coupling of fractional crystallisation and post-magmatic fluid-rock interactions on bulk rock composition. After emplacement, the resetting of clumped isotope signatures in carbonatites is facilitated by post-magmatic processes in both open and closed systems.
DS202101-0038
2020
Viladkar, S.G.Viladkar, S.G.First discovery of carbonatite in India.Journal of the Geological Society of India, Vol. 96, 6, pp. 623-624.Indiacarbonatite
DS202109-1492
2021
Viladkar, S.G.Viladkar, S.G., Sorokhtina, N.V.Evolution of pyrochlore in carbonatites of the Amba Dongar complex, India.Mineralogical Magazine, Vol. 85, 4, pp. 554-567.Indiadeposit - Amba Dongar

Abstract: Pyrochlore-group minerals are common accessory rare-metal bearing minerals in the calcite and ankerite carbonatites of the Amba Dongar complex (India). Pyrochlore from the Amba Dongar carbonatites differs from that in other Indian complexes in Ta, Zr, Ti, rare earth element (REE) and Pb contents, but is similar with respect to Ca, Ba and Sr abundances. The evolution of pyrochlore composition was studied to understand the alteration processes and the formation of late-stage pyrochlores enriched in REE and Pb. The early magmatic pyrochlore are calcio- and niobium-dominant types and were replaced by secondary cation-deficient varieties as a consequence of the action of hydrothermal fluids and supergene weathering. These processes produce changes mainly at the A site, rarely at the B site, and the original F is replaced by OH- groups. Calcium and Na can be extracted from the structure at the alteration stage and charge balance is achieved by the introduction of REE, Th, U, Ba or Sr. At the latest supergene stages, marginal and fractured zones of pyrochlore grains are altered to Pb-rich, Si-rich and cation-deficient hydrated varieties. The magmatic pyrochlore was crystallised in a highly alkaline environment at a high activity of Ca and at temperatures near 600°C, the alteration of pyrochlore began in a hydrothermal environment at temperatures below 350°C. The major compositional changes that are associated with the alteration are summarised by the following reactions: Ca2+ + Nb5+? REE3+ + Ti4+; Nb5+ + Fe3+ ? Ti4+ + Zr4+; and 2Nb5+ + Ca2+ ? Ti4+ + Si4+ + U4+.
DS202205-0727
2022
Viladkar, S.G.Viladkar, S.G.High-field strength elements in carbonatites of Siriwasan, Gujarat, India.Journal of Geological Society of India, Vol. 98, p. 440. 1p.Indiadeposit - Siriwasan
DS1993-1676
1993
Vilas, J.F.Vizan, H., Mena, M., Vilas, J.F.Pangea, the geoid, and the paths of virtual geomagnetic poles during polarity reversalsJournal of South American Earth Sciences, Vol. 6, No. 4, November pp. 253-266PangeaPaleomagnetism
DS1989-1556
1989
Vilayan, S.Vilayan, S., Melnyk, A.J., Singh, R.D., Nuttall, K.Rare earths: their mining, processing and growing industrial usageMining Engineering, Vol. 41, No. 1, January pp. 13-18. Database # 17622GlobalRare earths, Overview -economics
DS202102-0227
2021
Vilella, K.Vilella, K., Bodin, T., Boukare, C-E.,Deschamp, F., Badro, J., Ballmer, M.D. Li, Y.Constraints on the composition and temperature of LLSVPs from seismic properties of lower mantle minerals.Earth and Planetary Science Letters, Vol. 554, doi:10.1016/j.epsl.2020.116685Mantlegeophysics - seismic

Abstract: Here, we provide a reappraisal of potential LLSVPs compositions based on an improved mineralogical model including, for instance, the effects of alumina. We also systematically investigate the effects of six parameters: FeO and Al2O3 content, proportion of CaSiO3 and bridgmanite (so that the proportion of ferropericlase is implicitly investigated), Fe3+/?Fe and temperature contrast between far-field mantle and LLSVPs. From the 81 millions cases studied, only 79000 cases explain the seismic observations. Nevertheless, these successful cases involve a large range of parameters with, for instance, FeO content between 12--25~wt\% and Al2O3 content between 3--17~wt\%. We then apply a principal component analysis (PCA) to these cases and find two robust results: (i) the proportion of ferropericlase should be low (<6vol\%); (ii) the formation of Fe3+-bearing bridgmanite is much more favored than other iron-bearing phases. Following these results, we identify two end-member compositions, Bm-rich and CaPv-rich, and discuss their characteristics. Finally, we discuss different scenarios for the formation of LLSVPs and propose that investigating the mineral proportion produced by each scenario is the best way to evaluate their relevance. For instance, the solidification of a primitive magma ocean may produce FeO and Al2O3 content similar to those suggested by our analysis. However, the mineral proportion of such reservoirs is not well-constrained and may contain a larger proportion of ferropericlase than what is allowed by our results.
DS200712-1120
2007
Viles, H.A.Viles, H.A., Goudie, A.S.Rapid salt weathering in the coastal Namib desert: implications for Lands cape development.Geomorphology, Vol. 85, 1-2, March 15, pp. 49-62.Africa, NamibiaGeomorphology - not specific to diamonds
DS202102-0228
2021
Viles, H.A.Viles, H.A., Goudie, A.S., Goudie, A.M.Ants as geomorphological agents: a global assessment.Earth-Science Reviews, Vol. 213, doi.org/10.1016/j.earscirev.2020.103469 17p. PdfGlobalgeomorphology

Abstract: Ants are abundant in most of the world's terrestrial environments. They are energetic, strong for their size, numerous, and socially cooperative. They play many geomorphologically important roles. In particular, they construct mounds and subterranean galleries, create patterned ground, play a role in bioturbation, affect vegetation cover and soil properties (such as infiltration rate) and influence runoff and erosion. They also play roles in biogeochemical cycling and rock and mineral weathering. Here, we review and reanalyse data collected from over 80 studies on ant contributions to geomorphology from around the world. The clearest manifestation of the geomorphological role of ants is found in their various constructions, such as mounds. There can be hundreds or thousands of mounds per hectare, with a median density of 125 ha?1 recorded in the studies reviewed. The longevity of these features varies and some are stable while others are highly erodible. The construction of mounds and galleries causes bioturbation (pedoturbation), a role which ants share with termites, worms and many mammals. A median rate of 1.5 t ha?1 a?1 is derived from the studies reviewed. Ants also produce patterned ground through their effects on vegetation. The relationships between ant activity and runoff and erosion are complex and not consistent. Bioturbation of soil, tunnelling activity, the construction of underground chambers, galleries and macro-pores, the removal and/or accumulation of organic material, and changes in vegetation cover, are all mechanisms by which ants might modify soil infiltration characteristics. Because of their effect on soil infiltration rates, sediment provision and on vegetation cover, ants can have a profound influence on runoff and soil movement on slopes. Only a modest amount of work has been done to investigate the role that ants play in rock weathering. Ants are greatly affected by human activities (especially land cover changes), and some geomorphologically-active species have proved to be highly invasive. The response of ants to future climate changes needs further investigation.
DS2002-1667
2002
Vilhena Filho, C.Vilhena Filho, C.Main considerations in the formulation of mining policies to attract foreign investmentTranactions of the Institution of Mining and Metallurgy, Section B. Applied Earth, Vol. 111, pp. B177-182.GlobalMineral law and policy
DS200412-2060
2002
Vilhena Filho, C.Vilhena Filho, C.Main considerations in the formulation of mining policies to attract foreign investment.Transactions of the Institution of Mining and Metallurgy, Section B. Applied Earth Science ( incorporating Aus, Vol. 111, pp. B177-182.GlobalMineral law and policy
DS200712-0871
2006
Viljaya, V.Rao, Viljaya, V., Sain, K., Reddy, P.R., Mooney, W.D.Crustal structure and tectonics of the northern part of the southern Granulite Terrane, India.Earth and Planetary Science Letters, Vol. 251, 1-2, Nov. 15, pp.90-103.IndiaTectonics - not specific to diamonds
DS1995-0673
1995
ViljoenGreen, R.W.E., Smith, C.B., Jones, Muller, ViljoenProgress towards understanding the Kaapvaal lithosphere geophysical and geochemical perspectives.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 188-90.South AfricaGeophysics, Craton -Kaapvaal
DS1998-1159
1998
ViljoenPhillips, D., Kiviets, Barton, Smith, Viljoen, Fourie40 Ar39 dating of kimberlites and related rocks: problems and solutions7th. Kimberlite Conference abstract, pp. 690-2.South Africa, Botswana, ZimbabweGeochronology, Deposit - Venetia, Oaks, Colorssus, Lace, Rex, Pniel
DS1999-0555
1999
ViljoenPhillips, D., Kiviets, Barton, Smith, Viljoen, Fournie40 Ar-39 Ar dating of kimberlites and related rocks, problems and solutions.7th International Kimberlite Conference Nixon, Vol. 2, pp. 677-88.South Africa, Zimbabwe, Barkly WestGeochronology, argon, Venetia, Colossus, Postmas, Pniel, Marnitz, Rex, Lace
DS2003-1324
2003
ViljoenStachel, T., Aulbavh, S., Brey, G.P., Harris, J.W., Leost, I., Tappert, R., ViljoenDiamond formation and mantle metasomatism: a trace element perspective8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractGlobalDiamonds, database REE 135 peridotite garnet inclusions, Review - genesis
DS200712-0795
2007
ViljoenPage, F.Z., Fu, B., Kita, N.T., Fournelle, Spicuzza, Schulze, Viljoen, Basei, ValleyZircons from kimberlite: new insights into oxygen isotopes, trace elements, and Ti in zircon thermometry.Geochimica et Cosmochimica Acta, Vol. 71, 15, pp. 3887-3903.TechnologyZircon thermometry
DS1993-0167
1993
Viljoen, D.Broome, J., Brodaric, B., Viljoen, D., Baril, D.The NATMAP digital geoscience data-management systemComputers and Geosciences, Vol. 19, No. 10, pp. 1501-1516GlobalComputers, Program -NATMAP data management system
DS1997-0666
1997
Viljoen, D.Leclair, A.D., Viljoen, D.Geology of Precambrian basement beneath Phanerozoic cover, Flin Flon @Manitoba and SaskatchewanGeological Survey of Canada Open File, No. 3427, 1 poster $ 20.00Manitoba, SaskatchewanPoster, Basement - Phanerozoic
DS1997-0667
1997
Viljoen, D.Leclair, A.D., Viljoen, D.Geology of Precambrian basement beneath the Phanerozoic cover, Flin Flonbelt, Manitoba and Saskatchewan.Geological Survey of Canada, Open file 3427 POSTER, approx. 20.00Manitoba, SaskatchewanPrecambrian basement, POSTER.
DS1999-0095
1999
Viljoen, D.Broome, H.J., Viljoen, D.Application of digital methodology to the NATMAP Shield Margin ProjectCanadian Journal of Earth Sciences, Vol. 36, No. 2, Feb. pp. 161-73.Manitoba, SaskatchewanLithoprobe, Geophysics - seismics
DS1970-0688
1973
Viljoen, E.A.Frick, C., Viljoen, E.A.The Etosha Meterorite: a Medium Octahedrite from Southwestafrica.South African Journal of Science, Vol. 69, No. 11, PP. 345-348.Southwest Africa, NamibiaMeteorite
DS1995-1986
1995
Viljoen, E.A.Verwoerd, W.J., Viljoen, E.A., Chevallier, L.Rare metal mineralization at the Salpeterkop carbonatite complex, Western Cape ProvinceJournal of African Earth Sciences, Vol. 21, No. 1, July pp. 171-186South AfricaCarbonatite, Deposit -Salpeterkop
DS1995-1987
1995
Viljoen, E.A.Verwoerd, W.J., Viljoen, E.A., Chevallier, L.Rare metal mineralization at the Saltpeterkop carbonatite complex, Western Cape Province #1Journal of African Earth Sciences, Vol. 21, No. 1, July pp. 171-186.South AfricaCarbonatite, Deposit -Saltpeterkop
DS1995-1988
1995
Viljoen, E.A.Verwoerd, W.J., Viljoen, E.A., Chevallier, L.Rare metal mineralization at the Saltpeterkop carbonatite complex, Western Cape #2Geological Society Africa 10th. Conference Oct. Nairobi, p. 134-5. Abstract.South AfricaCarbonatite, rare earths, Deposit -Saltpeterkop
DS2001-0243
2001
Viljoen, F.Deines, P., Viljoen, F., Harris, J.W.Implications of the carbon isotope and mineral inclusion record for the formation of diamonds VenetiaGeochimica Et Cosmochimica Acta, Vol. 65, No. 5. Mar. 1, pp. 813-38.South AfricaMantle - underlying mobile belt, Deposit - Venetia
DS200812-1212
2008
Viljoen, F.Viljoen, F., Quadling, A.Diamond beneficiation linking science and politics.GSSA-SEG Meeting Held July, Johannesburg, 38 Power point slidesTechnologyMetallurgy
DS200912-0561
2009
Viljoen, F.Palot, M., Cartigny, P., Viljoen, F.Diamond origin and genesis: A C and N stable isotope study on diamonds from a single eclogitic xenolith ( Kaalvaalei, South Africa).Lithos, In press available 45p.Africa, South AfricaDiamond genesis
DS200912-0798
2009
Viljoen, F.Viljoen, F., Dobbe, R., Smit, B.Geochemical processes in peridotite xenoliths from the Premier diamond mine, South Africa: evidence -depletion and refertilization of subcratonic lithosphere.Lithos, In press availableAfrica, South AfricaDeposit - Premier
DS201012-0820
2010
Viljoen, F.Viljoen, F., Dobbe, R., Harris, J., Smit, B.Trace element chemistry of mineral inclusions in eclogitic diamonds from the Premier ( Cullinan) and Finsch kimberlites: implications for evolution mantleLithos, Vol. 118, 1-2, pp. 156-168.Africa, South AfricaDiamond genesis, source
DS201212-0430
2012
Viljoen, F.Maier, W.D., Peltonen, P., McDonald, I., Barnes, S.J., Barnes, S-J., Hatton, C., Viljoen, F.The concentration of platinum group elements and gold in southern African and Karelian kimberlite hosted mantle xenoliths: implications for the noble metal content of the Earth's mantle.Chemical Geology, Vol. 302-303, pp. 119-135.Africa, southern AfricaKimberlite - PGM
DS201412-0386
2012
Viljoen, F.Huizenga, J.M., Crossingham, A., Viljoen, F.Diamond precipitation from ascending reduced fluids in the Kaapvaal lithosphere: thermodynamic constraints.Comptes Rendus Geoscience, Vol. 344, pp. 67-76.Africa, South AfricaRedox melting
DS201601-0038
2015
Viljoen, F.Perritt, S., Preston, R., Viljoen, F., Van Der Linde, G.Morphology, micro-structure and chemistry of a deformed garnet megacryst suite from Montelo kimberlite, Free State Province, South Africa.South African Journal of Geology, Vol. 118, 4, pp. 439-454.Africa, South AfricaDeposit - Montelo
DS201910-2272
2019
Viljoen, F.Khan, S., Dongre, A., Viljoen, F., Li, Q., Le Roux, P.Petrogenesis of lamprophyres synchronous to kimberlites from the Wajrakarur kimberlite field: implications for contrasting lithospheric mantle sources and geodynamic evolution of the eastern Dharwar craton of southern India.Geological Journal, Vol. 54, 5, pp. 2994-3016.Indiadeposit - Wajrakarur

Abstract: Kimberlite field is an example of widespread Mesoproterozoic intracontinental magmatism. Recent studies have identified deep subcontinental lithospheric mantle as a source region of the kimberlite magmatism while timing, origin, and processes responsible for the generation of coeval lamprophyres remain poorly constrained. Here, we present and discuss new petrological and geochemical data for two lamprophyre dykes from the Wajrakarur kimberlite field and assess their petrogenetic relation to the kimberlite occurrences. Based on mineral compositional and whole?rock geochemical characters, it is suggested that lamprophyres are formed through low degrees of partial melting of “enriched” lithospheric mantle that was modified and metasomatized by melts derived from recycled crust. This differs from geochemical imprints found in coeval kimberlites, where a crustal source component appears to be absent and is more consistent with rock derivation from “depleted” lithosphere which has experienced interaction with asthenosphere?derived melts. An apparent lack of garnet in the mantle sources of lamprophyres is suggestive of melting at comparatively shallow depth (~100 km) relative to the kimberlites. Hence, these geochemically contrasting rocks, although have formed at the same time, are derived from vertically heterogeneous lithospheric mantle sources and can be explained through and linked with a thermal anomaly in the underlying convective asthenosphere. We suggest that the deeper mantle source region of the kimberlites was more pristine and devoid of subduction?related signatures, whereas the shallower mantle source region of the lamprophyres seems to have preserved imprints of plate convergence and subduction associated with the evolution of the Dharwar Craton.
DS202009-1657
2020
Viljoen, F.Shaikh, A.M., Tappe, S., Bussweiler, Y., Patel, S.C., Ravi, S., Bolhar, R., Viljoen, F.Clinopyroxene and garnet mantle cargo in kimberlites as probes of Dharwar craton architecture and geotherms, with implications for post-1.1 Ga lithosphere thinning events beneath southern India.Journal of Petrology, in press available, 73p. PdfIndiadeposit - Wajrakarur

Abstract: The Wajrakarur Kimberlite Field (WKF) on the Eastern Dharwar Craton in southern India hosts several occurrences of Mesoproterozoic kimberlites, lamproites, and ultramafic lamprophyres, for which mantle-derived xenoliths are rare and only poorly preserved. The general paucity of mantle cargo has hampered the investigation of the nature and evolution of the continental lithospheric mantle (CLM) beneath cratonic southern India. We present a comprehensive study of the major and trace element compositions of clinopyroxene and garnet xenocrysts recovered from heavy mineral concentrates for three ca. 1.1 Ga old WKF kimberlite pipes (P7, P9, P10), with the goal to improve our understanding of the cratonic mantle architecture and its evolution beneath southern India. The pressure-temperature conditions recorded by peridotitic clinopyroxene xenocrysts, estimated using single-pyroxene thermobarometry, suggest a relatively moderate cratonic mantle geotherm of 40?mW/m2 at 1.1 Ga. Reconstruction of the vertical distribution of clinopyroxene and garnet xenocrysts, combined with some rare mantle xenoliths data, reveals a compositionally layered CLM structure. Two main lithological horizons are identified and denoted as layer A (?80-145?km depth) and layer B (?160-190?km depth). Layer A is dominated by depleted lherzolite with subordinate amounts of pyroxenite, whereas layer B comprises mainly refertilised and Ti-metasomatised peridotite. Harzburgite occurs as a minor lithology in both layers. Eclogite stringers occur within the lower portion of layer A and at the bottom of layer B near the lithosphere-asthenosphere boundary at 1.1 Ga. Refertilisation of layer B is marked by garnet compositions with enrichment in Ca, Ti, Fe, Zr and LREE, although Y is depleted compared to garnet in layer A. Garnet trace element systematics such as Zr/Hf and Ti/Eu indicate that both kimberlitic and carbonatitic melts have interacted with and compositionally overprinted layer B. Progressive changes in the REE systematics of garnet grains with depth record an upward percolation of a continuously evolving metasomatic agent. The intervening zone between layers A and B at ?145-160?km depth is characterised by a general paucity of garnet. This ‘garnet-paucity’ zone and an overlying type II clinopyroxene-bearing zone (?115-145?km) appear to be rich in hydrous mineral assemblages of the MARID- or PIC kind. The composite horizon between ?115-160?km depth may represent the product of intensive melt/rock interaction by which former garnet was largely reacted out and new metasomatic phases such as type II clinopyroxene and phlogopite plus amphibole were introduced. By analogy with better-studied cratons, this ‘metasomatic horizon’ may be a petrological manifestation of a former mid-lithospheric discontinuity at 1.1 Ga. Importantly, the depth interval of the present-day lithosphere-asthenosphere boundary beneath Peninsular India as detected in seismic surveys coincides with this heavily overprinted metasomatic horizon, which suggests that post-1.1 Ga delamination of cratonic mantle lithosphere progressed all the way to mid-lithospheric depth. This finding implies that strongly overprinted metasomatic layers, such as the ‘garnet-paucity’ zone beneath the Dharwar craton, present structural zones of weakness that aid lithosphere detachment and foundering in response to plate tectonic stresses.
DS202103-0406
2020
Viljoen, F.Shaikh, A.M., Tappe, S., Bussweiler, Y., Patel, S.C., Ravi, S., Bolhar, R., Viljoen, F.Clinopyroxene and garnet mantle cargo in kimberlites as probes of Dharwar craton architecture and geotherms, with implications for post -1.1 Ga lithosphere thinning events beneath southern India.Journal of Petrology, Vol. 61, 9, egaa087 23p. PdfIndiadeposit - Wajrakarur

Abstract: The Wajrakarur Kimberlite Field (WKF) on the Eastern Dharwar Craton in southern India hosts several occurrences of Mesoproterozoic kimberlites, lamproites and ultramafic lamprophyres, for which mantle-derived xenoliths are rare and only poorly preserved. The general paucity of mantle cargo has hampered the investigation of the nature and evolution of the continental lithospheric mantle (CLM) beneath cratonic southern India. We present a comprehensive study of the major and trace element compositions of clinopyroxene and garnet xenocrysts recovered from heavy mineral concentrates for three c.1•1?Ga old WKF kimberlite pipes (P7, P9, P10), with the goal to improve our understanding of the cratonic mantle architecture and its evolution beneath southern India. The pressure-temperature conditions recorded by peridotitic clinopyroxene xenocrysts, estimated using single-pyroxene thermobarometry, suggest a relatively moderate cratonic mantle geotherm of 40 mW/m2 at 1•1?Ga. Reconstruction of the vertical distribution of clinopyroxene and garnet xenocrysts, combined with some rare mantle xenoliths data, reveals a compositionally layered CLM structure. Two main lithological horizons are identified and denoted as layer A (?80-145?km depth) and layer B (?160-190?km depth). Layer A is dominated by depleted lherzolite with subordinate amounts of pyroxenite, whereas layer B comprises mainly refertilised and Ti-metasomatized peridotite. Harzburgite occurs as a minor lithology in both layers. Eclogite stringers occur within the lower portion of layer A and at the bottom of layer B near the lithosphere-asthenosphere boundary at 1•1?Ga. Refertilisation of layer B is marked by garnet compositions with enrichment in Ca, Ti, Fe, Zr and LREE, although Y is depleted compared to garnet in layer A. Garnet trace element systematics such as Zr/Hf and Ti/Eu indicate that both kimberlitic and carbonatitic melts have interacted with and compositionally overprinted layer B. Progressive changes in the REE systematics of garnet grains with depth record an upward percolation of a continuously evolving metasomatic agent. The intervening zone between layers A and B at ?145-160?km depth is characterized by a general paucity of garnet. This ‘garnet-paucity’ zone and an overlying type II clinopyroxene-bearing zone (?115-145?km) appear to be rich in hydrous mineral assemblages of the MARID- or PIC kind. The composite horizon between ?115-160?km depth may represent the product of intensive melt/rock interaction by which former garnet was largely reacted out and new metasomatic phases such as type II clinopyroxene and phlogopite plus amphibole were introduced. By analogy with better-studied cratons, this ‘metasomatic horizon’ may be a petrological manifestation of a former mid-lithospheric discontinuity at 1•1?Ga. Importantly, the depth interval of the present-day lithosphere-asthenosphere boundary beneath Peninsular India as detected in seismic surveys coincides with this heavily overprinted metasomatic horizon, which suggests that post-1•1?Ga delamination of cratonic mantle lithosphere progressed all the way to mid-lithospheric depth. This finding implies that strongly overprinted metasomatic layers, such as the ‘garnet-paucity’ zone beneath the Dharwar craton, present structural zones of weakness that aid lithosphere detachment and foundering in response to plate tectonic stresses.
DS1988-0733
1988
Viljoen, K.S.Viljoen, K.S.The Kimberley mine dumps- a window into the earth's interiorUnknown, Vol. 31, No. 1, pp. 29-30South AfricaBlank
DS1988-0734
1988
Viljoen, K.S.Viljoen, K.S., Lawless, P.J.Finsch mine-the largest diamond producer in South AfricaGeoBulletin, Vol. 31, No. 1, pp. 48-49South AfricaBlank
DS1989-1557
1989
Viljoen, K.S.Viljoen, K.S.Petrography of the Kaladar kimberlite, CanadaAuthor's preprint, 3p., 3p.Ontario, KaladarPetrography
DS1989-1558
1989
Viljoen, K.S.Viljoen, K.S.Petrography of the Kaladar kimberlite, CanadaAuthor's preprint, 3p., 3p.Ontario, KaladarPetrography
DS1991-1525
1991
Viljoen, K.S.Schulze, D.J., Valley, J.W., Viljoen, K.S., Spicuzza, M.Carbon isotope composition of graphite in mantle eclogitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 353-355South Africa, BotswanaXenoliths, Bellsbank, Jagersfontein, Orapa, Letlhakane, eclogites
DS1991-1601
1991
Viljoen, K.S.Skinner, E.M.W., Viljoen, K.S., Clark, T.C., Smith, C.B.The petrography, tectonic setting and emplacement ages of kimberlites In the south western border region of the Kaapvaal craton, Prieska area, RSA #1Proceedings of Fifth International Kimberlite Conference held Araxa June, pp. 373-375South AfricaKaapvaal craton- Prieska, Geochronology, petrography
DS1991-1802
1991
Viljoen, K.S.Viljoen, K.S., Robinson, D.N., Swash, P.M.Diamond and graphite peridotite xenoliths from the Roberts Victor mineProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 440-442South AfricaPetrography, mineral chemistry, Geothermobarometry, diamond morphology
DS1992-1607
1992
Viljoen, K.S.Viljoen, K.S., Swash, P.J., Otter, M.L., Schulze, D.J.Diamondiferous garnet harzburgites from the Finsch kimberlite, northernCape, South AfricaContributions to Mineralogy and Petrology, Vol. 110, No. 1, March pp. 133-138South AfricaGarnet harzburgite, Diamonds
DS1994-1622
1994
Viljoen, K.S.Skinner, E.M.W., Viljoen, K.S., Clark, T.C., Smith, C.B.The Petrography, tectonic setting and emplacement ages of kimberlites In the southwest border region Kaapvaal craton #2Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 80-97.South AfricaPetrography kimberlites, Deposit -Prieska
DS1994-1857
1994
Viljoen, K.S.Viljoen, K.S.Eclogite xenoliths from kimberlites, South Africa and BotswanaUniversity of Witwatersrand, Ph.d. thesisSouth Africa, BotswanaXenoliths, Thesis
DS1994-1858
1994
Viljoen, K.S.Viljoen, K.S., Robinson, D.N., Swash, P.M., Griffin, W.L., OtterDiamond and graphite bearing peridotite xenoliths from the Roberts Victorkimberlite.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 285-303.South AfricaXenoliths, Deposit -Roberts Victor
DS1995-1776
1995
Viljoen, K.S.Smith, C.B., Green, R.W.E., Jones, M., Viljoen, K.S.Progress two ards understanding the evolution of the Kaapvaal lithosphere:the mantle perspective.Centennial Geocongress (1995) Extended abstracts, Vol. 1, p. 343-346. abstractSouth AfricaCraton, Mantle
DS1995-1994
1995
Viljoen, K.S.Viljoen, K.S.Graphite - and diamond bearing eclogite xenoliths from the Bellsbankkimberlites, Northern Cape, South Africa.Contributions to Mineralogy and Petrology, Vol. 121, No. 4, pp. 414-423.South AfricaEclogites, Deposit -Bellsbank
DS1995-1995
1995
Viljoen, K.S.Viljoen, K.S.Diamond genesis in the eclogitic environment... Star, Lace, Mir, Doornkloof, Orapa, Finsch, Argyle...Centennial Geocongress (1995) Extended abstracts, Vol. 1, p. 940-943. abstractSouth Africa, Russia, BotswanaEclogites, Diamond genesis
DS1995-1996
1995
Viljoen, K.S.Viljoen, K.S., Lawless, P.J.Finsch mine - the largest diamond producer in South AfricaMdd/seg Guidebook Nov., 18p.South AfricaBrief overview, Deposit -Finsch
DS1995-1997
1995
Viljoen, K.S.Viljoen, K.S., Skinner, E.M.W., Loubser, J.M.Petrology of the Postmasburg kimberlitesProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 653-655.South AfricaPetrology, deposit -Postmasburg, Finch
DS1996-1480
1996
Viljoen, K.S.Viljoen, K.S., Smith, C.B., Sharp, Z.D.Stable and radiogenic isotope study of eclogite xenoliths from the Orapakimberlite, Botswana.Chemical Geology, Vol 131, No. 1-4, Sept. 30, pp. 235-BotswanaGeochronology, eclogite xenoliths, Deposit - Orapa
DS1997-1010
1997
Viljoen, K.S.Schulze, D.J., Valley, J.W., Viljoen, K.S., StiefenhoferCarbon isotope composition of graphite in mantle ecologitesJournal of Geology, Vol. 105, No. 3, May pp. 379-386.South Africa, Wyoming, BotswanaEclogites, geochronology, Jagersfontein, Deposit - Schaffer, Letlhakane, Orapa, Bellsbank, Blaau
DS1997-1108
1997
Viljoen, K.S.Stiefenhofer, J., Viljoen, K.S., Marsh, J.S.Petrology and geochemistry of the Eldor carbonatite complex LabradorTrough, Quebec.Contrib. Mineralogy and Petrology, Vol. 127, No. 1-2, pp. 147-158.BotswanaGeochemistry, Deposit - Letlhkane
DS1998-0684
1998
Viljoen, K.S.Janney, P.E., Le Roex, A.P., Viljoen, K.S.Trace element and isotopic characteristics of olivine melilitites from The western Cape: source for Group I.7th International Kimberlite Conference Abstract, pp. 374-6.South Africa, NamaqualandCape Fold Belt, Melilitites, Group I kimberlites
DS1998-0912
1998
Viljoen, K.S.Mabuza, M., Viljoen, K.S., Majola, S.New diamond bearing xenoliths from the Orapa mine, Botswana7th International Kimberlite Conference Abstract, pp. 521-23.BotswanaXenoliths, Deposit - Orapa
DS1998-1247
1998
Viljoen, K.S.Rodionov, A.S., Viljoen, K.S.Venetia megacrysts, northern Province, South Africa7th. Kimberlite Conference abstract, pp. 743-5.South AfricaMineral chemistry, Deposit - Venetia
DS1998-1398
1998
Viljoen, K.S.Stachel, T., Viljoen, K.S., Harris, J.W.Metasomatic processes in lherzolitic and harzburgitic domains of diamondiferous lithospheric mantle: rare earth elements (REE).Earth and Planetary Science Letters, Vol. 159, No. 1-2, June 15, pp. 1-12.MantleGarnets - xenoliths, Diamond inclusions
DS1998-1399
1998
Viljoen, K.S.Stachel, T., Viljoen, K.S., Harris, J.W., Brey, G.P.rare earth elements (REE) patterms of garnets from diamonds and Diamondiferous geochemical signatures7th International Kimberlite Conference Abstract, pp. 862-4.South Africa, GhanaDiamond source, Deposit - Roberts Victor, BiriM.
DS1998-1413
1998
Viljoen, K.S.Stiefenhofer, J., Viljoen, K.S., Tainton, K.M., DobbeThe petrology of a mantle xenolith suite from Venetia, South Africa #17th International Kimberlite Conference Abstract, pp. 868-70.South AfricaPeridotite, Deposit - Venetia
DS1998-1545
1998
Viljoen, K.S.Viljoen, K.S., Phillips, D., Harris, J.W., Robinson, D.Mineral inclusions in diamonds from the Venetia kimberlites, NorthernProvince, South Africa.7th International Kimberlite Conference Abstract, pp. 943-5.South AfricaDiamond morphology - garnet inclusions, Deposit - Venetia
DS1999-0772
1999
Viljoen, K.S.Viljoen, K.S., Phillips, D., Harris, J.W., Robinson, D.Mineral inclusions in diamonds from the Venetia kimberlites, Northern Province, South Africa.7th International Kimberlite Conference Nixon, Vol. 2, pp. 888-95.South AfricaDiamond - inclusions, mineral chemistry, Deposit - Venetia
DS2001-0754
2001
Viljoen, K.S.McDonald, I., Harris, J.W., Viljoen, K.S.Can the nickel copper platinum group elements (PGE) signatures of sulphide inclusions in diamond help to constrain diamond formation processes?Institute of Mining and Metallurgy (IMM) Transactions. Durham Meeting absts., Vol. 110, p. B46. abstractGlobalDiamond - inclusions, genesis
DS2002-0764
2002
Viljoen, K.S.Janney, P.E., LeRoex, A.P., Carlson, R.W., Viljoen, K.S.A chemical and multi isotope study of the western Cape olivine melilitite province SouthJournal of Petrology, Vol. 43, 12, pp. 2339-70.South AfricaGeochemistry - HIMU signature, Geochronology
DS2002-1668
2002
Viljoen, K.S.Viljoen, K.S.An infrared investigation of inclusion bearing diamonds from the Venetia kimberlite, northern province, South Africa: implications for diamonds from craton margin seContributions to Mineralogy and Petrology, Vol. 144, 1, Oct. pp. 98-108.South AfricaDiamond inclusions, Deposit - Venetia
DS2003-0024
2003
Viljoen, K.S.Appleyard, C.M., Viljoen, K.S., Dobbe, R.A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractSouth AfricaEclogites, diamonds, melting, Deposit - Finsch
DS2003-1238
2003
Viljoen, K.S.Schulze, D.J., Valley, J.W., Viljoen, K.S., Spicuzza, M.J.Oxygen isotope composition of mantle eclogites8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractSouth Africa, ColoradoEclogites and Diamonds, Geochronology
DS2003-1429
2003
Viljoen, K.S.Viljoen, K.S., Dobbe, R.A Diamondiferous lherzolite from the Premier diamond mine, South Africa8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractSouth AfricaDeposit - Premier
DS200412-0044
2003
Viljoen, K.S.Appleyard, C.M., Viljoen, K.S., Dobbe, R.A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe, South Africa.8 IKC Program, Session 2, AbstractAfrica, South AfricaEclogite, diamonds, melting Deposit - Finsch
DS200412-0045
2004
Viljoen, K.S.Appleyard, C.M., Viljoen, K.S., Dobbe, R.A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe, South Africa.Lithos, Vol. 77, 1-4, Sept. pp. 317-332.Africa, South AfricaProterozoic, dodecahedra, deformation, type IaAB, plate
DS200412-0290
2004
Viljoen, K.S.Cartigny, P., Chinn, I., Viljoen, K.S., Robinson, D.Early Proterozoic ultrahigh pressure metamorphism: evidence from microdiamonds.Science, Vol. 304, 5672, May 7, pp. 853-4.TechnologyMicrodiamonds, UHP
DS200412-0890
2004
Viljoen, K.S.Jacob, D.E., Kronz, A., Viljoen, K.S.Cohenite, native iron and troilite inclusions in garnets from polycrystalline diamond aggregates.Contributions to Mineralogy and Petrology, Vol. 146, 5, pp. 566-76.Africa, South AfricaDiamond inclusions
DS200412-1542
2004
Viljoen, K.S.Phillips, D., Harris, J.W., Viljoen, K.S.Mineral chemistry and thermobarometry of inclusions from De Beers Pool diamonds, Kimberley, South Africa.Lithos, Vol. 77, 1-4, Sept. pp. 155-179.Africa, South AfricaDiamond Inclusions, silicate, oxide, harzburgitic
DS200412-1906
2003
Viljoen, K.S.Stachel, T., Aulbavh, S., Brey, G.P., Harris, J.W., Leost, I., Tappert, R., Viljoen, K.S.Diamond formation and mantle metasomatism: a trace element perspective.8 IKC Program, Session 3, AbstractTechnologyDiamonds, database REE 135 peridotite garnet inclusions Review - genesis
DS200412-1913
2004
Viljoen, K.S.Stachel, T., Viljoen, K.S., McDade,P.,Harris, J.W.Diamondiferous lithospheric roots along the western margin of the Kalahari Craton - the peridotitic inclusion suites in diamondsContributions to Mineralogy and Petrology, Vol. 147, 1, pp. 32-47.Africa, BotswanaDiamond genesis, Orapa, Jwaneng deposits
DS200412-2061
2003
Viljoen, K.S.Viljoen, K.S., Dobbe, R.A Diamondiferous lherzolite from the Premier diamond mine, South Africa.8 IKC Program, Session 6, POSTER abstractAfrica, South AfricaMantle petrology Deposit - Premier
DS200512-0062
2005
Viljoen, K.S.Banas, A., Shimizu, T., Viljoen, K.S.Trace element composition of garnet inclusions in diamonds from the De Beers pool, South Africa.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Africa, South AfricaKimberley mines, geochemistry magmatism, Kapvaal Craton
DS200512-0950
2005
Viljoen, K.S.Schulze, D.J., Harte, B., Channer, D.M.DrR., Spicuzza, M.J., Viljoen, K.S.Stable isotope evidence for a subduction origin for mantle eclogites and their diamonds.GAC Annual Meeting Halifax May 15-19, Abstract 1p.United States, ColoradoGeochronology, diamond genesis
DS200512-1142
2005
Viljoen, K.S.Viljoen, K.S., Schulze, D.J.Contrasting Group 1 and Group II eclogite compositions: implications for eclogitic diamond genesis.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Africa, South Africa, BotswanaKapvaal Craton, geochemistry
DS200512-1143
2005
Viljoen, K.S.Viljoen, K.S., Schulze, D.J., Quadling, A.G.Comtrasting Group I and Group II eclogite xenolith petrogenesis: petrological, trace element and isotopic evidence from eclogite, garnet websterite and akremiteJournal of Petrology, Vol. 46, 10, Oct. pp. 2059-2090.Africa, South AfricaXenoliths, Kaalvaalei kimberlite
DS200712-0706
2006
Viljoen, K.S.McDonald, I., Viljoen, K.S.Platinum group element geochemistry of mantle eclogites: a reconnaissance study of xenoliths from the Orapa kimberlite, Botswana.Transactions of Institute of Mining and Metallurgy, Vol. 115, no. 3, Sept. pp. B 81-93.Africa, BotswanaDeposit - Orapa, PGE, eclogites
DS200912-0031
2009
Viljoen, K.S.Banas, A., Stachel, T., Phillips, D., Shimizu, N., Viljoen, K.S., Harris, J.W.Ancient metasomatism recorded by ultra-depleted garnet inclusions in diamonds from De Beers Pool, South Africa.Lithos, In press availableAfrica, South AfricaDeposit - DeBeers Pool
DS201012-0132
2010
Viljoen, K.S.Cunningham, A., Huizenga, J.M., Viljoen, K.S.A theoretical examination of diamond precipitation from fluids in the Earth's mantle.International Mineralogical Association meeting August Budapest, abstract p. 184.MantleDiamond genesis
DS201012-0821
2010
Viljoen, K.S.Viljoen, K.S., Harris, J.W., Ivanic, T., Richardson, S.H., Whitehead, K.Trace element geochemistry and Ni thermometry of garnet inclusions in peridotitic diamonds from Premier and Finsch, South Africa: implications - diamond formationInternational Mineralogical Association meeting August Budapest, abstract p. 187.Africa, South AfricaGeochemistry
DS201312-0513
2013
Viljoen, K.S.Kramers, J.D., Andreoli, M.A.G., Atanasova, M., Belyanin, G.A., Block, D.L., Franklyn, C., Harris, C., Lekgoathi, M., Montross, C.S., Ntsoane, T., Pischedda, V., Segonyane, P., Viljoen, K.S., Westraadt, J.E.Unique chemistry of a diamond bearing pebble from the Libyan desert glass strewnfield, SW Egypt: evidence for a shocked comet fragment.Earth and Planetary Science Letters, Vol.382, pp. 21-31.Africa, EgyptShock diamonds
DS201412-0949
2014
Viljoen, K.S.Viljoen, K.S., Harris, J.W., Richardson, S.H., Gray, K.Trace element chemistry of peridotitic garnets in diamonds from the Premier ( Cullinan) and Finsch kimberlites, South Africa: contrasting styles of mantle metasomatism.Lithos, Vol. 208-209, pp. 1-15.Africa, South AfricaDeposit - Premier, Finsch
DS201508-0351
2015
Viljoen, K.S.Dongre, A.N., Viljoen, K.S., Ma, M.The Pipe-15 kimberlite: a new addition to the Wajrakarur cluster of the Wajrakarur kimberlite field, Eastern Dharwar craton, southern India.Journal of the Geological Society of India, Vol. 86, 1, pp. 71-79.IndiaDeposit - Pipe-15
DS201511-1820
2015
Viljoen, K.S.Aulbach , S., Viljoen, K.S.Eclogite xenoliths from the Lace kimberlite, Kaapvaal craton: from convecting mantle source to palaeo-ocean floor and back.Earth and Planetary Science Letters, Vol. 431, pp. 274-286.Africa, South AfricaDeposit - Lace

Abstract: Major- and trace-element compositions of eclogite and pyroxenite xenoliths of ?2.5 Ga age (in situ Pb-Pb data on clinopyroxene) from the Lace kimberlite on the Kaapvaal craton were investigated in order to constrain: (1) the nature and evolution of their protoliths; (2) the extent to which they preserve information on the state of the asthenospheric mantle source that gave rise to their low-pressure protoliths; and (3) the effect of their deep recycling on the radiogenic isotope evolution of the convecting mantle. Their elemental relationships are consistent with low-pressure fractionation of olivine ± plagioclase and clinopyroxene during oceanic crust formation, whereby the residual melt was enriched in rare-earth elements (REE), high field-strength elements and Y, producing inverse correlations of ?REE with the size of Eu- and Sr-anomalies. LREE-depletion may indicate loss of on average 20% of a partial melt upon subduction and metamorphism (eclogitisation) of oceanic crust, which did not, however, contribute to juvenile growth of continental crust. The eclogites have median Sm/Nd (0.40) and Lu/Hf (0.27) similar to Depleted Mantle, and lower U/Pb (0.02) and Th/Pb (0.02). If deeply subducted, these rocks cannot explain unradiogenic Nd and Hf, and radiogenic Pb isotope compositions in the sources of some modern ocean island basalts. Low incompatible trace-element contents similar to picrites, and Yb concentrations at a given TiO2 content similar to modern MORB, indicate derivation of the protoliths by average melt fractions of ?0.20-0.25?0.20-0.25 that left a spinel peridotite residue at pressures ?2.5 to 3.0 GPa. This shallow intersection of the peridotite solidus suggests moderate Archaean ambient mantle potential temperatures of ?1420 to 1470?°C. Samples filtered for clinopyroxene fractionation and metasomatism have V/Sc (4.7±1.24.7±1.2; n=11n=11) indicating lower fO2fO2 (?1.9 relative to the fayalite-magnetite-quartz buffer=?FMQbuffer=?FMQ) than modern MORB. This is in part due to the higher average melt extraction pressure (?1.5 GPa) during formation of their crustal protoliths. Extrapolation to 1 GPa, similar to the average pressure of present-day MORB generation, yields ?FMQ of ?1.7±1.1?1.7±1.1, corresponding to Fe3+# of 0.07±0.040.07±0.04. If these results are correct, they suggest an Archaean ambient mantle more reducing than at present, with implications for the speciation of volatiles, which affects the mantle solidus and the composition of volcanic gases. This has implications for the Archaean atmospheric redox evolution and the recycling of carbon and other volatiles.
DS201603-0373
2016
Viljoen, K.S.Dongre, A.N., Viljoen, K.S., Chalapathi Rao, N.V., Gucsik, A.Origin of Ti rich garnets in the groundmass of Wajrakarur field kimberlites, southern India: insights from EPMA and Raman spectroscopy.Mineralogy and Petrology, in press available, 13p.IndiaDeposit - Wajrakur

Abstract: Although Ti-rich garnets are commonly encountered in the groundmass of many alkaline igneous rocks, they are comparatively rare in kimberlites. Here we report on the occurrence of Ti-rich garnets in the groundmass of the P-15 and KL-3 kimberlites from the diamondiferous Wajrakarur field in the Eastern Dharwar craton of southern India. These garnets contain considerable Ti (11.7-23.9 wt.% TiO2), Ca (31.3-35.8 wt.% CaO), Fe (6.8-15.5 wt.% FeOT) and Cr (0.04-9.7 wt.% Cr2O3), but have low Al (0.2-5.7 wt.% Al2O3). In the case of the P-15 kimberlite they display a range in compositions from andradite to schorlomite, with a low proportion of grossular (andradite(17.7-49.9)schorlomite(34.6-49.5)-grossular(3.7-22.8)-pyrope(1.9-10.4)). A few grains also contain significant chromium and represent a solid solution between schorlomite and uvarovite. The Ti-rich garnets in the KL-3 kimberlite, in contrast, are mostly schorlomitic (54.9?90.9 mol %) in composition. The Ti-rich garnets in the groundmass of these two kimberlites are intimately associated with chromian spinels, perhaps suggesting that the garnet formed through the replacement of spinel. From the textural evidence, it appears unlikely that the garnets could have originated through secondary alteration, but rather seem to have formed through a process in which early magmatic spinels have reacted with late circulating, residual fluids in the final stages of crystallization of the kimberlite magma. Raman spectroscopy provides evidence for low crystallinity in the spinels which is likely to be a result of their partial transformation into andradite during their reaction with a late-stage magmatic (kimberlitic) fluid. The close chemical association of these Ti-rich garnets in TiO2-FeO-CaO space with those reported from ultramafic lamprophyres (UML) is also consistent with results predicted by experimental studies, and possibly implies a genetic link between kimberlite and UML magmas. The occurrence of Ti-rich garnets of similar composition in the Swartruggens orangeite on the Kaapvaal craton in South Africa, as well as in other kimberlites with an orangeitic affinity (e.g. the P-15 kimberlite on the Eastern Dharwar craton in southern India), is inferred to be a reflection of the high Ca- and high Ti-, and the low Al-nature, of the parent magma (i.e. Group II kimberlites).
DS201605-0828
2016
Viljoen, K.S.Dongre, A.N., Viljoen, K.S., Chalapathi Rao, N.V.Origins of Ti-rich garnets in the groundmass of Wajrakarur field kimberlites, southern India: insights from EPMA and Raman spectroscopy.Mineralogy and Petrology, Vol. 110, 2, pp. 295-307.IndiaDeposit - Wajrakarur

Abstract: Although Ti-rich garnets are commonly encountered in the groundmass of many alkaline igneous rocks, they are comparatively rare in kimberlites. Here we report on the occurrence of Ti-rich garnets in the groundmass of the P-15 and KL-3 kimberlites from the diamondiferous Wajrakarur field in the Eastern Dharwar craton of southern India. These garnets contain considerable Ti (11.7-23.9 wt.% TiO2), Ca (31.3-35.8 wt.% CaO), Fe (6.8-15.5 wt.% FeOT) and Cr (0.04-9.7 wt.% Cr2O3), but have low Al (0.2-5.7 wt.% Al2O3). In the case of the P-15 kimberlite they display a range in compositions from andradite to schorlomite, with a low proportion of grossular (andradite(17.7-49.9)schorlomite(34.6-49.5)-grossular(3.7-22.8)-pyrope(1.9-10.4)). A few grains also contain significant chromium and represent a solid solution between schorlomite and uvarovite. The Ti-rich garnets in the KL-3 kimberlite, in contrast, are mostly schorlomitic (54.9?90.9 mol %) in composition. The Ti-rich garnets in the groundmass of these two kimberlites are intimately associated with chromian spinels, perhaps suggesting that the garnet formed through the replacement of spinel. From the textural evidence, it appears unlikely that the garnets could have originated through secondary alteration, but rather seem to have formed through a process in which early magmatic spinels have reacted with late circulating, residual fluids in the final stages of crystallization of the kimberlite magma. Raman spectroscopy provides evidence for low crystallinity in the spinels which is likely to be a result of their partial transformation into andradite during their reaction with a late-stage magmatic (kimberlitic) fluid. The close chemical association of these Ti-rich garnets in TiO2-FeO-CaO space with those reported from ultramafic lamprophyres (UML) is also consistent with results predicted by experimental studies, and possibly implies a genetic link between kimberlite and UML magmas. The occurrence of Ti-rich garnets of similar composition in the Swartruggens orangeite on the Kaapvaal craton in South Africa, as well as in other kimberlites with an orangeitic affinity (e.g. the P-15 kimberlite on the Eastern Dharwar craton in southern India), is inferred to be a reflection of the high Ca- and high Ti-, and the low Al-nature, of the parent magma (i.e. Group II kimberlites).
DS201612-2295
2016
Viljoen, K.S.Dongre, A., Chalapathi Rao, N.V., Viljoen, K.S., Lehmann, B.Petrology, genesis and geodynamic implication of the Mesoproterozoic- Late Cretaceous Timmasamudram kimberlite cluster, Wajrakarur field, eastern Dharwar craton, southern India.Geoscience Frontiers, in press availableIndiaDeposit - Timmasamudram

Abstract: New mineralogical and bulk-rock geochemical data for the recently recognised Mesoproterozoic (ca. 1100 Ma) and late Cretaceous (ca. 90 Ma) kimberlites in the Timmasamudram cluster (TKC) of the Wajrakarur kimberlite field (WKF), Eastern Dharwar Craton, southern India, are presented. On the basis of groundmass mineral chemistry (phlogopite, spinel, perovskite and clinopyroxene), bulk-rock chemistry (SiO2, K2O, low TiO2, Ba/Nb and La/Sm), and perovskite Nd isotopic compositions, the TK-1 (macrocrystic variety) and TK-4 (microcrystic variety) kimberlites in this cluster are here classified as orangeites (i.e. Group II kimberlites), with geochemical characteristics that are very similar to orangeites previously described from the Bastar Craton in central India, as well as the Kaapvaal Craton in South Africa. The remaining kimberlites (e.g., TK-2, TK-3 and the TK-1 microcrystic variant), are more similar to other 1100 Ma, Group I-type kimberlites of the Eastern Dharwar Craton, as well as the typical Group I kimberlites of the Kaapvaal Craton. Through the application of geochemical modelling, based on published carbonated peridotite/melt trace element partition coefficients, we show that the generation of the TKC kimberlites and the orangeites results from low degrees of partial melting of a metasomatised, carbonated peridotite.
DS201709-1956
2017
Viljoen, K.S.Aulbach, S., Jacob, D.E., Cartigny, P., Stern, R.A., Simonetti, S.S., Worner, G., Viljoen, K.S.Eclogite xenoliths from Orapa: ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin.Geochimica et Cosmochimica Acta, Vol. 213, pp. 574-592.Africa, Botswanadeposit - Orapa

Abstract: Major- and trace-element compositions of garnet and clinopyroxene, as well as 87Sr/86Sr in clinopyroxene and ?18O in garnet in eclogite and pyroxenite xenoliths from Orapa, at the western margin of the Zimbabwe craton (central Botswana), were investigated in order to trace their origin and evolution in the mantle lithosphere. Two groups of eclogites are distinguished with respect to 87Sr/86Sr: One with moderate ratios (0.7026-0.7046) and another with 87Sr/86Sr >0.7048 to 0.7091. In the former group, heavy ?18O attests to low-temperature alteration on the ocean floor, while 87Sr/86Sr correlates with indices of low-pressure igneous processes (Eu/Eu?, Mg#, Sr/Y). This suggests relatively undisturbed long-term ingrowth of 87Sr at near-igneous Rb/Sr after metamorphism, despite the exposed craton margin setting. The high-87Sr/86Sr group has mainly mantle-like ?18O and is suggested to have interacted with a small-volume melt derived from an aged phlogopite-rich metasome. The overlap of diamondiferous and graphite-bearing eclogites and pyroxenites over a pressure interval of ?3.2 to 4.9 GPa is interpreted as reflecting a mantle parcel beneath Orapa that has moved out of the diamond stability field, due to a change in geotherm and/or decompression. Diamondiferous eclogites record lower median 87Sr/86Sr (0.7039) than graphite-bearing samples (0.7064) and carbon-free samples (0.7051), suggesting that interaction with the - possibly oxidising - metasome-derived melt caused carbon removal in some eclogites, while catalysing the conversion of diamond to graphite in others. This highlights the role of small-volume melts in modulating the lithospheric carbon cycle. Compared to diamondiferous eclogites, eclogitic inclusions in diamonds are restricted to high FeO and low SiO2, CaO and Na2O contents, they record higher equilibrium temperatures and garnets have mostly mantle-like O isotopic composition. We suggest that this signature was imparted by a sublithospheric melt with contributions from a clinopyroxene-rich source, possibly related to the ca. 2.0 Ga Bushveld event.
DS201709-1957
2017
Viljoen, K.S.Aulbach, S., Woodland, A.B., Vasileyev, P., Galvez, M.E., Viljoen, K.S.Effects of low pressure igneous processes and subduction on Fe3/Fe and redox state of mantle eclogites from Lace ( Kaapvaal craton).Earth and Planetary Science Letters, Vol. 474, pp. 283-295.Africa, South Africadeposit - Lace

Abstract: Reconstructing the redox state of the mantle is critical in discussing the evolution of atmospheric composition through time. Kimberlite-borne mantle eclogite xenoliths, commonly interpreted as representing former oceanic crust, may record the chemical and physical state of Archaean and Proterozoic convecting mantle sources that generated their magmatic protoliths. However, their message is generally obscured by a range of primary (igneous differentiation) and secondary processes (seawater alteration, metamorphism, metasomatism). Here, we report the Fe3+/?Fe ratio and ?18 O in garnet from in a suite of well-characterised mantle eclogite and pyroxenite xenoliths hosted in the Lace kimberlite (Kaapvaal craton), which originated as ca. 3 Ga-old ocean floor. Fe3+/?Fe in garnet (0.01 to 0.063, median 0.02; n = 16) shows a negative correlation with jadeite content in clinopyroxene, suggesting increased partitioning of Fe3+ into clinopyroxene in the presence of monovalent cations with which it can form coupled substitutions. Jadeite-corrected Fe3+/?Fe in garnet shows a broad negative trend with Eu*, consistent with incompatible behaviour of Fe3+ during olivine-plagioclase accumulation in the protoliths. This trend is partially obscured by increasing Fe3+ partitioning into garnet along a conductive cratonic geotherm. In contrast, NMORB-normalised Nd/Yb - a proxy of partial melt loss from subducting oceanic crust (<1) and metasomatism by LREE-enriched liquids (>1) - shows no obvious correlation with Fe3+/?Fe, nor does garnet ?18OVSMOW (5.14 to 6.21‰) point to significant seawater alteration. Median bulk-rock Fe3+/?Fe is roughly estimated at 0.025. This observation agrees with V/Sc systematics, which collectively point to a reduced Archaean convecting mantle source to the igneous protoliths of these eclogites compared to the modern MORB source. Oxygen fugacites (fO2) relative to the fayalite-magnetite-quartz buffer (FMQ) range from ?log ? fO2 = FMQ-1.3 to FMQ-4.6. At those reducing conditions, the solubility of carbon in the fluids released by dehydration is higher than in fluids closer to FMQ. The implication is that Archean processes of C transport and deposition would have differed from those known in modern-style subduction zones, and diamond would have formed from methane-rich fluids. In addition, such reducing material could drive redox melting or freezing upon deep recycling and migration of CH4-bearing fluids into the ambient mantle.
DS201710-2212
2017
Viljoen, K.S.Aulbach, S., Jacob, D.E., Cartigny, P., Stern, R.A., Simonetti, S.S., Womer, G., Viljoen, K.S.Eclogite xenoliths from Orapa: Ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin.Geochimica et Cosmochinica Acta, Vol. 213, pp. 574-592.Africa, Botswanadeposit - Orapa

Abstract: Major- and trace-element compositions of garnet and clinopyroxene, as well as 87Sr/86Sr in clinopyroxene and ?18O in garnet in eclogite and pyroxenite xenoliths from Orapa, at the western margin of the Zimbabwe craton (central Botswana), were investigated in order to trace their origin and evolution in the mantle lithosphere. Two groups of eclogites are distinguished with respect to 87Sr/86Sr: One with moderate ratios (0.7026-0.7046) and another with 87Sr/86Sr >0.7048 to 0.7091. In the former group, heavy ?18O attests to low-temperature alteration on the ocean floor, while 87Sr/86Sr correlates with indices of low-pressure igneous processes (Eu/Eu?, Mg#, Sr/Y). This suggests relatively undisturbed long-term ingrowth of 87Sr at near-igneous Rb/Sr after metamorphism, despite the exposed craton margin setting. The high-87Sr/86Sr group has mainly mantle-like ?18O and is suggested to have interacted with a small-volume melt derived from an aged phlogopite-rich metasome. The overlap of diamondiferous and graphite-bearing eclogites and pyroxenites over a pressure interval of ?3.2 to 4.9 GPa is interpreted as reflecting a mantle parcel beneath Orapa that has moved out of the diamond stability field, due to a change in geotherm and/or decompression. Diamondiferous eclogites record lower median 87Sr/86Sr (0.7039) than graphite-bearing samples (0.7064) and carbon-free samples (0.7051), suggesting that interaction with the - possibly oxidising - metasome-derived melt caused carbon removal in some eclogites, while catalysing the conversion of diamond to graphite in others. This highlights the role of small-volume melts in modulating the lithospheric carbon cycle. Compared to diamondiferous eclogites, eclogitic inclusions in diamonds are restricted to high FeO and low SiO2, CaO and Na2O contents, they record higher equilibrium temperatures and garnets have mostly mantle-like O isotopic composition. We suggest that this signature was imparted by a sublithospheric melt with contributions from a clinopyroxene-rich source, possibly related to the ca. 2.0 Ga Bushveld event.
DS201809-1991
2017
Viljoen, K.S.Aulbach, S., Jacob, D.E., Cartigny, P., Stern, R.A., Simonetti, S.S., Worner, G., Viljoen, K.S.Eclogite xenoliths from Orapa: Ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin.Geochimica et Cosmochimica Acta, Vol. 213, 1, pp. 574-592.Africa, Botswanadeposit - Orapa

Abstract: Major- and trace-element compositions of garnet and clinopyroxene, as well as 87Sr/86Sr in clinopyroxene and ?18O in garnet in eclogite and pyroxenite xenoliths from Orapa, at the western margin of the Zimbabwe craton (central Botswana), were investigated in order to trace their origin and evolution in the mantle lithosphere. Two groups of eclogites are distinguished with respect to 87Sr/86Sr: One with moderate ratios (0.7026-0.7046) and another with 87Sr/86Sr >0.7048 to 0.7091. In the former group, heavy ?18O attests to low-temperature alteration on the ocean floor, while 87Sr/86Sr correlates with indices of low-pressure igneous processes (Eu/Eu?, Mg#, Sr/Y). This suggests relatively undisturbed long-term ingrowth of 87Sr at near-igneous Rb/Sr after metamorphism, despite the exposed craton margin setting. The high-87Sr/86Sr group has mainly mantle-like ?18O and is suggested to have interacted with a small-volume melt derived from an aged phlogopite-rich metasome. The overlap of diamondiferous and graphite-bearing eclogites and pyroxenites over a pressure interval of ?3.2 to 4.9 GPa is interpreted as reflecting a mantle parcel beneath Orapa that has moved out of the diamond stability field, due to a change in geotherm and/or decompression. Diamondiferous eclogites record lower median 87Sr/86Sr (0.7039) than graphite-bearing samples (0.7064) and carbon-free samples (0.7051), suggesting that interaction with the - possibly oxidising - metasome-derived melt caused carbon removal in some eclogites, while catalysing the conversion of diamond to graphite in others. This highlights the role of small-volume melts in modulating the lithospheric carbon cycle. Compared to diamondiferous eclogites, eclogitic inclusions in diamonds are restricted to high FeO and low SiO2, CaO and Na2O contents, they record higher equilibrium temperatures and garnets have mostly mantle-like O isotopic composition. We suggest that this signature was imparted by a sublithospheric melt with contributions from a clinopyroxene-rich source, possibly related to the ca. 2.0 Ga Bushveld event.
DS201812-2776
2019
Viljoen, K.S.Aulbach, S., Heaman, L.M., Jacob, D.E., Viljoen, K.S.Ages and sources of mantle eclogites: ID-TIMS and in situ MC-ICPMS Pb-Sr isotope sytematics of clinopyroxene.Chemical Geology, Vol. 503, pp. 15-28.Mantleeclogite

Abstract: Strontium and Pb isotopic compositions of clinopyroxene (cpx) in selected samples from three well-characterised eclogite suites with oceanic crustal protoliths (Lace/Kaapvaal craton, Orapa/Zimbabwe craton and Koidu/West African craton) were acquired by high-precision isotope dilution thermal ionisation mass spectrometry (ID-TIMS) and in situ multicollector-laser ablation-inductively-coupled plasma mass spectrometry (MC-LA-ICPMS). The aims of this study are twofold: (1) assess their utility to obtain formation or resetting age constraints and identify elemental signatures that enhance the chances of successful age dating, and (2) to confirm the veracity and utility of results obtained by novel MC-LA-ICPMS techniques. Strontium-Pb isotope systematics of eclogitic cpx measured in this study are decoupled and may reflect addition of unsupported radiogenic Sr during seawater alteration or interaction with oceanic sediments in subduction mélanges, and/or disturbance due to mantle metasomatism, to which the more incompatible Pb is more susceptible. Despite a complex history, subsets of samples yield meaningful model dates. Clinopyroxene fractions from Lace with high Pb contents (36?ppm), unradiogenic Pb isotopic compositions (206Pb/204Pb?=?13.5713.52) and low 238U/204Pb (1.01.5) give single-stage model Pb dates of 2.902.84?Ga. In contrast, samples from Orapa plot to the right of the Geochron and do not yield meaningful Pb model ages. However, these data do define secondary isochrons that can be modelled to yield minimum age constraints on major events affecting the cratonic lithosphere. Within the uncertainties, the resultant 2.18?±?0.45?Ga age obtained for Koidu eclogites reflect disturbance of the Pb isotope system due to subduction beneath the craton linked to the Eburnean orogeny, while they retained their unradiogenic 87Sr/86Sr (0.7016). Similarly, the age for samples from Orapa (2.20?±?0.54?Ga) is interpreted as an overprint age related to Palaeoproterozoic accretion at the western craton margin. Gabbroic eclogites (Eu/Eu*?>?1) with plagioclase-rich protoliths having low time-integrated Rb/Sr and U/Pb retain the least radiogenic Sr and, in part, Pb. High model ? (9.0 to 9.1) for several eclogites from Lace with elevated LREE, Th and Pb abundances reflects ca. 3.0?Ga addition of a sedimentary component, possibly derived from reworking of a high-? basaltic protocrust, as observed on other cratons. We suggest that sample targeting can be usefully guided by fast-throughput in situ LA-ICPMS techniques, which largely yield results identical to ID-TIMS, albeit at lower precision, and which can further help identify kimberlite contamination in the mineral separates used for solution work.
DS201812-2897
2018
Viljoen, K.S.Viljoen, K.S., Perritt, S.H., Chinn, I.L.An unusual suite of eclogitic, websteritic and transitional websteritic-lherzolitic diamonds from the Voorspoed kimberlite in South Africa: mineral inclusions and infrared characteristics.Lithos, Vol. 320-321, pp. 416-434.Africa, South Africadeposit - Voorspoed

Abstract: A study of the morphology, mineral inclusions, nitrogen content, and nitrogen aggregation state of diamonds from the Voorspoed kimberlite, was conducted. The diamonds are characterised by a highly unusual inclusion mineral paragenesis dominated by eclogitic and transitional websteritic-lherzolitic inclusions along with related websteritic inclusions, while a comparatively minor harzburgitic diamond inclusion suite account for the remainder. This differs substantially from many of the diamond populations in kimberlites on the Kaapvaal Craton where a harzburgitic inclusion paragenesis predominates. Only in the case of the Orapa kimberlite in Botswana has a similar diamond inclusion suite been encountered before, although in that instance an eclogitic and websteritic inclusion suite predominate. Calculated garnet-clinopyroxene equilibration temperatures, at an assumed pressure of 50?kbar, range from 1040 °C to 1296?°C. Temperatures of 1114?°C to 1348?°C, at 50?kbar, are calculated for lamellar orthopyroxene-clinopyroxene intergrowths. ‘Reconstituted’ pyroxenes mathematically reconstructed from the lamellar orthopyroxene-clinopyroxene intergrowths produce temperatures of 1238?°C to 1416?°C, suggesting that the lithosphere cooled by at least 100?°C after diamond crystallisation. Nitrogen contents and nitrogen aggregation states of whole diamonds range from below the detection limit (~10?ppm) to 1442 atomic ppm (average 167 atomic ppm), and up to 97% of the highly aggregated ‘B' component (average 65%), respectively. The elevated aggregation state of the nitrogen in the diamonds from Voorspoed, coupled with a high level of platelet degradation in many of the diamonds analysed, relative to a world-wide database, is unusual, but broadly comparable to diamonds from kimberlites occurring in craton margin settings, such as Argyle and Venetia. Diamond inclusion thermobarometry, as well as the elevated nitrogen aggregation states of the diamonds (coupled with the evidence for platelet degradation in the diamonds) are indicative of a diamond crystallisation event associated with a transient thermal pulse, as well as associated deformation of the mantle containing the diamonds. The websteritic and the transitional websteritic-lherzolitic mantle source rocks of the Voorspoed diamonds likely formed through melt infiltration into mantle peridotite, possibly in the reaction envelope surrounding an ascending mantle plume. In order to account for the unusually low abundance of harzburgitic diamonds at Voorspoed, it is postulated that a primary, pre-existing suite of harzburgitic diamonds which have crystallised in the Mesoarchaean, was destroyed through heating and oxidation during the passage of magmas associated with the Ventersdorp large igneous province at 2.72?Ga, and which was subsequently followed by the crystallisation of a younger eclogitic and transitional websteritic-lherzolitic suite of diamonds.
DS201902-0257
2019
Viljoen, K.S.Aulbach, S., Heaman, L.M., Jacob, D., Viljoen, K.S.Ages and sources of mantle eclogites: ID-TIMS and in situ MC-ICPMS Pb-Sr isotope systematics of clinopyroxene.Chemical Geology, Vol. 503, pp. 15-28.Africa, South Africa, Zimbabwe, Sierra Leonedeposit - Lace, Orapa, Koidu

Abstract: Strontium and Pb isotopic compositions of clinopyroxene (cpx) in selected samples from three well-characterised eclogite suites with oceanic crustal protoliths (Lace/Kaapvaal craton, Orapa/Zimbabwe craton and Koidu/West African craton) were acquired by high-precision isotope dilution thermal ionisation mass spectrometry (ID-TIMS) and in situ multicollector-laser ablation-inductively-coupled plasma mass spectrometry (MC-LA-ICPMS). The aims of this study are twofold: (1) assess their utility to obtain formation or resetting age constraints and identify elemental signatures that enhance the chances of successful age dating, and (2) to confirm the veracity and utility of results obtained by novel MC-LA-ICPMS techniques. Strontium-Pb isotope systematics of eclogitic cpx measured in this study are decoupled and may reflect addition of unsupported radiogenic Sr during seawater alteration or interaction with oceanic sediments in subduction mélanges, and/or disturbance due to mantle metasomatism, to which the more incompatible Pb is more susceptible. Despite a complex history, subsets of samples yield meaningful model dates. Clinopyroxene fractions from Lace with high Pb contents (3-6?ppm), unradiogenic Pb isotopic compositions (206Pb/204Pb?=?13.57-13.52) and low 238U/204Pb (1.0-1.5) give single-stage model Pb dates of 2.90-2.84?Ga. In contrast, samples from Orapa plot to the right of the Geochron and do not yield meaningful Pb model ages. However, these data do define secondary isochrons that can be modelled to yield minimum age constraints on major events affecting the cratonic lithosphere. Within the uncertainties, the resultant 2.18?±?0.45?Ga age obtained for Koidu eclogites reflect disturbance of the Pb isotope system due to subduction beneath the craton linked to the Eburnean orogeny, while they retained their unradiogenic 87Sr/86Sr (0.7016). Similarly, the age for samples from Orapa (2.20?±?0.54?Ga) is interpreted as an overprint age related to Palaeoproterozoic accretion at the western craton margin. Gabbroic eclogites (Eu/Eu*?>?1) with plagioclase-rich protoliths having low time-integrated Rb/Sr and U/Pb retain the least radiogenic Sr and, in part, Pb. High model ? (9.0 to 9.1) for several eclogites from Lace with elevated LREE, Th and Pb abundances reflects ca. 3.0?Ga addition of a sedimentary component, possibly derived from reworking of a high-? basaltic protocrust, as observed on other cratons. We suggest that sample targeting can be usefully guided by fast-throughput in situ LA-ICPMS techniques, which largely yield results identical to ID-TIMS, albeit at lower precision, and which can further help identify kimberlite contamination in the mineral separates used for solution work.
DS202002-0161
2019
Viljoen, K.S.Aulbach, S., Woodland, A.B., Stern, R.A., Vasilyev, P., Heaman, L.M., Viljoen, K.S.Evidence for a dominantly reducing Archaean ambient mantle from two redox proxies, and low oxygen fugacity of deeply subducted oceanic crust.Nature Research Scientific Reports, https://doi.org/10.1038/ s41598-019-55743-1 11p. PdfMantlemelting, redox

Abstract: Privacy Policy. You can manage your preferences in 'Manage Cookies'. Oxygen fugacity (fO2) is an intensive variable implicated in a range of processes that have shaped the Earth system, but there is controversy on the timing and rate of oxidation of the uppermost convecting mantle to its present fO2 around the fayalite-magnetite-quartz oxygen buffer. Here, we report Fe3+/?Fe and ƒf2 for ancient eclogite xenoliths with oceanic crustal protoliths that sampled the coeval ambient convecting mantle. Using new and published data, we demonstrate that in these eclogites, two redox proxies, V/Sc and Fe3+/?Fe, behave sympathetically, despite different responses of their protoliths to differentiation and post-formation degassing, seawater alteration, devolatilisation and partial melting, testifying to an unexpected robustness of Fe3+/?Fe. Therefore, these processes, while causing significant scatter, did not completely obliterate the underlying convecting mantle signal. Considering only unmetasomatised samples with non-cumulate and little-differentiated protoliths, V/Sc and Fe3+/?Fe in two Archaean eclogite suites are significantly lower than those of modern mid-ocean ridge basalts (MORB), while a third suite has ratios similar to modern MORB, indicating redox heterogeneity. Another major finding is the predominantly low though variable estimated fO2 of eclogite at mantle depths, which does not permit stabilisation of CO2-dominated fluids or pure carbonatite melts. Conversely, low-fO2 eclogite may have caused efficient reduction of CO2 in fluids and melts generated in other portions of ancient subducting slabs, consistent with eclogitic diamond formation ages, the disproportionate frequency of eclogitic diamonds relative to the subordinate abundance of eclogite in the mantle lithosphere and the general absence of carbonate in mantle eclogite. This indicates carbon recycling at least to depths of diamond stability and may have represented a significant pathway for carbon ingassing through time.
DS202006-0910
2020
Viljoen, K.S.Aulbach, S., Viljoen, K.S., Gerdes, A.Diamondiferous and barren eclogites and pyroxenites from the western Kaapvaal craton record subduction processes and mantle metasomatism respectively.Lithos, in press available 52p. PdfAfrica, South Africadeposit - Doomkloof-Sover

Abstract: Mineral major and trace elements combined with Sr isotopes of clinopyroxene are used to unravel the origins and evolution of mantle eclogite and pyroxenite xenoliths from the Doornkloof-Sover orangeite dike (western Kaapvaal craton), and to investigate the generation and destruction of diamond in these rocks. Two different eclogite types are present: (1) MgO-poor eclogites (MgO?=?7.3 to 14.5?wt%; n?=?43) with accessory diamond ± corundum and kyanite; garnet grossular content (median Ca#?=?0.25) and clinopyroxene jadeite content (0.39). Reconstructed bulk rocks are LREE-depleted (median La 0.29?ppm) and have low median Cr2O3 (0.06?wt%) and incompatible trace-element contents (e.g. Sr, Zr, Ba, Pb, Th), and high Li and transition metal abundances. Some are characterised by stepped REE patterns or steep slopes in the MREE, similar to eclogites affected by interaction with dehydration fluids generated in subduction zones. These fluids may also have deposited diamond in typically reducing eclogite assemblages at diamond-stable pressures. (2) MgO-rich eclogites and pyroxenites (MgO?=?14.0 to 20.0?wt%; n?=?29), which are barren and enriched in LREE (median La 1.39?ppm), Cr2O3 (0.25?wt%) and incompatible trace elements, with lower Li and transition metal abundances than the MgO-poor group. These are typical signatures of carbonated ultramafic melt metasomatism in the mantle lithosphere. Strontium isotopic compositions vary widely in both groups, but high Cr2O3 and Ba contents are dominantly associated with 87Sr/86Sr?>?0.7055. This reflects interaction with metasomatic agents remobilised from ancient lithospheric metasomes, which eventually gave rise to regional orangeite magmatism. The presence of strong positive Eu anomalies in both groups, including two pyroxenites, requires low-pressure igneous protoliths, presumably derived from a ca. 3?Ga spreading ridge, as reported for other eclogite materials from the western Kaapvaal craton. Based on the proportions of MgO-poor and -rich eclogites and pyroxenites, approximately 40% of the diamond inventory were destroyed by mantle metasomatism centred at ~135?±?15?km depth, overlapping a low-velocity anomaly (mid-lithospheric discontinuity). Two diamondiferous orangeites ?20?km from Doornkloof-Sover contain significantly different eclogite xenolith populations: At Newlands, MgO-poor diamondiferous eclogites are present in addition to barren MgO-rich ones and pyroxenite, suggesting that the host orangeite sampled a source region equally affected by diamond-destructive mantle metasomatism, whereas at Bellsbank, all eclogites are MgO-poor and LREE-depleted. This may explain higher diamond grades reported for this locality compared to Newlands or Doornkloof-Sover.
DS202008-1368
2019
Viljoen, K.S.Aulbach, S., Woodand, A.B., Stern, R.A., Vasileyev, P., Heaman, L.M., Viljoen, K.S.Evidence for a dominantly reducing Archean ambient mantle from two redox proxies, and low oxygen fugacity of deeply subducted oceanic crust. Nature Research Scientific Reports, Vol. 9:20190 doir.org/10.38 /s41598-019-55743-1, 11p. PdfMantleeclogite

Abstract: Oxygen fugacity (ƒO2) is an intensive variable implicated in a range of processes that have shaped the Earth system, but there is controversy on the timing and rate of oxidation of the uppermost convecting mantle to its present ƒO2 around the fayalite-magnetite-quartz oxygen buffer. Here, we report Fe3+/?Fe and ƒO2 for ancient eclogite xenoliths with oceanic crustal protoliths that sampled the coeval ambient convecting mantle. Using new and published data, we demonstrate that in these eclogites, two redox proxies, V/Sc and Fe3+/?Fe, behave sympathetically, despite different responses of their protoliths to differentiation and post-formation degassing, seawater alteration, devolatilisation and partial melting, testifying to an unexpected robustness of Fe3+/?Fe. Therefore, these processes, while causing significant scatter, did not completely obliterate the underlying convecting mantle signal. Considering only unmetasomatised samples with non-cumulate and little-differentiated protoliths, V/Sc and Fe3+/?Fe in two Archaean eclogite suites are significantly lower than those of modern mid-ocean ridge basalts (MORB), while a third suite has ratios similar to modern MORB, indicating redox heterogeneity. Another major finding is the predominantly low though variable estimated ƒO2 of eclogite at mantle depths, which does not permit stabilisation of CO2-dominated fluids or pure carbonatite melts. Conversely, low-ƒO2 eclogite may have caused efficient reduction of CO2 in fluids and melts generated in other portions of ancient subducting slabs, consistent with eclogitic diamond formation ages, the disproportionate frequency of eclogitic diamonds relative to the subordinate abundance of eclogite in the mantle lithosphere and the general absence of carbonate in mantle eclogite. This indicates carbon recycling at least to depths of diamond stability and may have represented a significant pathway for carbon ingassing through time.
DS200712-1078
2007
Viljoen, K.S.F.Thmassot, E., Cartigny, P., Harris, J.W., Viljoen, K.S.F.Methane related diamond crystallization in the Earth's mantle: stable isotope evidence from a single diamond bearing xenolith.Earth and Planetary Science Letters, Vol. 257, pp. 362-371.MantleDiamond genesis
DS200712-1079
2007
Viljoen, K.S.F.Thomassot, E., Cartigny, P., Harris, J.W., Viljoen, K.S.F.Methane related deiamond crystallization in the Earth's mantle: stable isotope evidences from a single diamond bearing xenolith.Earth and Planetary Science Letters, Vol. 257, 3-4, May 30, pp. 362-371.Africa, South AfricaXenolith
DS200812-0841
2008
Viljoen, K.S.F.Palot, M., Cartigny, P., Viljoen, K.S.F.Diamond origin and genesis: A C and N stable isotope study of diamonds from a single eclogite xenolith Kaalvaalei South Africa.Goldschmidt Conference 2008, Abstract p.A720.Africa, South AfricaDeposit - Kaalvallei
DS200612-1482
2006
Viljoen, M.J.Viljoen, M.J., Viljoen, R.P.Alluvial diamonds in South Africa.Journal of the Geological Society of India, Vol. 67, pp. 404-406.Africa, South AfricaHistory, placers
DS2000-0251
2000
Viljoen, R.M.DuPlessis, I., Viljoen, R.M., Smit, J.T.Novel liberation technology... mentions diamond processing but not specific to diamonds.Minerals Engineering, Conference 2p, abstractSouth AfricaMineral processing - comminution
DS1994-1661
1994
Viljoen, R.P.Sokolov, A.L., Viljoen, R.P., Scheglov, A.D.Mineral provinces and tectonic regimes: ancient platforms, mobile belts and zones of tectonic-magmaticExploration and Mining Geology, Vol. 3, No. 4, Oct. pp. 315-328South Africa, RussiaMetallogeny -overview, Tectonics, belts, zones
DS200612-1482
2006
Viljoen, R.P.Viljoen, M.J., Viljoen, R.P.Alluvial diamonds in South Africa.Journal of the Geological Society of India, Vol. 67, pp. 404-406.Africa, South AfricaHistory, placers
DS200612-1483
2005
Viljoen, R.P.Viljoen, R.P.Geological comparison between India and southern India and southern Africa - implications for diamond exploration.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 12-14.India, Africa, South AfricaBrief overview
DS200912-0169
2009
Viljoen, R.P.Devaraju, T.C., Viljoen, R.P., Sawkar, R.H., Sudhakara, T.L.Mafic and ultramafic magmatism and associated mineralization in the Dharwar Craton, southern India.Journal of the Geological Society of India, Vol. 73, 1, pp. 73-100.IndiaMagmatism
DS201707-1319
2017
Viljpoen, K.S.Dongre, A., Chalapathi Rao, N.V., Viljpoen, K.S., Lehmann, B.Petrology, genesis and geodynamic implication of the Mesoproterozoic - Late Cretaceous Timmasamudram kimberlite cluster, Wajrakarur field, eastern Dharwar Craton, southern India.Geoscience Frontiers, Vol. 8, pp. 541-553.Indiadeposit - Timmasamudram

Abstract: New mineralogical and bulk-rock geochemical data for the recently recognised Mesoproterozoic (ca. 1100 Ma) and late Cretaceous (ca. 90 Ma) kimberlites in the Timmasamudram cluster (TKC) of the Wajrakarur kimberlite field (WKF), Eastern Dharwar Craton, southern India, are presented. On the basis of groundmass mineral chemistry (phlogopite, spinel, perovskite and clinopyroxene), bulk-rock chemistry (SiO2, K2O, low TiO2, Ba/Nb and La/Sm), and perovskite Nd isotopic compositions, the TK-1 (macrocrystic variety) and TK-4 (Macrocrystic variety) kimberlites in this cluster are here classified as orangeites (i.e. Group II kimberlites), with geochemical characteristics that are very similar to orangeites previously described from the Bastar Craton in central India, as well as the Kaapvaal Craton in South Africa. The remaining kimberlites (e.g., TK-2, TK-3 and the TK-1 microcrystic variant), are more similar to other 1100 Ma, Group I-type kimberlites of the Eastern Dharwar Craton, as well as the typical Group I kimberlites of the Kaapvaal Craton. Through the application of geochemical modelling, based on published carbonated peridotite/melt trace element partition coefficients, we show that the generation of the TKC kimberlites and the orangeites results from low degrees of partial melting of a metasomatised, carbonated peridotite. Depleted mantle (TDM) Nd perovskite model ages of the 1100 Ma Timmasamudram kimberlites show that the metasomatic enrichment of their source regions are broadly similar to that of the Mesoproterozoic kimberlites of the EDC. The younger, late Cretaceous (ca. 90 Ma) TK-1 (macrocrystic variant) and TK-4 kimberlites, as well as the orangeites from the Bastar Craton, share similar Nd model ages of 1100 Ma, consistent with a similarity in the timing of source enrichment during the amalgamation of Rodinia supercontinent. The presence of late Cretaceous diamondiferous orangeite activity, presumably related to the location of the Marion hotspot in southern India at the time, suggests that thick lithosphere was preserved, at least locally, up to the late Cretaceous, and was not entirely destroyed during the breakup of Gondwana, as inferred by some recent geophysical models.
DS1986-0837
1986
Vilkovich, R.V.Vilkovich, R.V., Pozharitskaya, L.K.Composition evolution of carbonatites from the Chernigov zone(Azovsea).(Russian)Geochemistry International (Geokhimiya), (Russian), No. 3, pp. 318-327RussiaCarbonatite
DS1986-0838
1986
Vilkovich, R.V.Vilkovich, R.V., Pozharitskaya, L.K.Compositional evolution of carbonatites in the Chernigov zone,AzovregionGeochemistry International, Vol. 23, No. 7, pp. 92-100RussiaCarbonatite
DS1994-0934
1994
Vilkovsky, V.A.Kolesnik, V.N., Vilkovsky, V.A.Chemical composition of natural pyrope an indicator of specific features deep seated petrogenesis peridotites.Doklady Academy of Sciences Nauk. (Russian), Vol. 339, No. 1, Nov. pp. 73-76. #PX778RussiaGeochemistry, Peridotites
DS1996-0768
1996
Vilkovsky, V.A.Kolesnik, Yu.N., Vilkovsky, V.A.Composition of natural pyrope as an indicator of the deep seated petrogenesis of peridotites.Doklady Academy of Sciences, Vol. 342 No. 4, May, pp. 73-78.RussiaAlluvials, placers, Garnets
DS2000-0215
2000
VillaDe Sigoyer, J., Chavagnac, Blichert-Toft, Villa, LuaisDating the Indian continental subduction and collisional thickening in northwest Himalaya: eclogitesGeology, Vol. 28, No. 6, June pp. 487-90.IndiaSubduction - multichronology, Geochronology - Tso Morari eclogites
DS2001-0175
2001
VillaChavagnac, V., Jahn, Villa, Whitehouse, LiuMultichronometric evidence for an in situ origin of the ultra high pressure metamorphic terrane of Dabie Shan.Journal of Geology, Vol. 109, pp. 633-46.Chinaultra high pressure (UHP), Qinling - Dabie orogenic belt
DS1991-1803
1991
Villa, I.G.Villa, I.G.Excess Argon geochemistry in potassic volcanitesSchweiz. Mineral. Petrogr. Mitt, Vol. 71, pp. 205-219ItalyVolcanics, Leucites, sanidines, kalsilite
DS1986-0839
1986
Villa, I.M.Villa, I.M.Argon excess and mantle provenance in leucitesTerra Cognita, Vol. 6, No. 1, p. 32. (abstract.)GlobalLeucite
DS1994-1140
1994
Villa, I.M.McClenaghan, M.P., Seymour, D.B., Villa, I.M.Lamprophyre dike suites from western Tasmania, their radiometric dating And the age of thrust faulting in the Point Hibbs area.Australian Journal of Earth Sciences, Vol. 41, No. 1, February pp. 47-54.Australia, TasmaniaMinettes, Lamprophyres
DS1995-0906
1995
Villa, I.M.Kamber, B.S., Blenkinsop, T.G., Villa, I.M., Dahl, P.S.Proterozoic transpressive deformation in the northern marginal zone, Limpopo Belt, ZimbabweJournal of Geology, Vol. 103, No. 5, Sept. pp. 493-508ZimbabweTectonics,, Limpopo Belt
DS200512-1144
2005
Villa, I.M.Villa, I.M.From nanometer to megameter: isotopes, atomic-scale processes, and continent scale tectonic models.Lithos, In press,MantleGeochronology, recrystalization, geothermometry
DS201802-0277
2017
Villa, I.M.Villa, I.M., Hanchar, J.M.Age discordance and mineralogy.American Mineralogist, Vol. 102, pp. 2422-2439.Technologygeochronology

Abstract: Observations of discordant ages, meaning that an age given by one mineral geochronometer is different from the age given by another geochronometer from the same rock, began in the early days of geochronology. In the late 1950s and 1960s, discordant U-Pb zircon ages were unquestioningly attributed to Pb diffusion at high temperature. Later, the mineralogical properties and the petrogenesis of the zircon crystals being dated was recognized as a key factor in obtaining concordant U-Pb ages. Advances in analytical methods allowed the analysis of smaller and smaller zircon multigrain fractions, then the analysis of individual grains, and even pieces of grains, with higher degrees of concordancy. Further advances allowed a higher analytical precision, a clearer perception of accuracy, and a better statistical resolution of age discordance. As for understanding the cause(s) of discordance, belief revision followed the coupling of imaging, cathodoluminescence (CL), and backscattered electrons (BSE), to in situ dating by secondary ion mass spectrometry (SIMS) or by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Discordant zircon and other accessory minerals (e.g., monazite, apatite, etc.) often consist of young rims accreted onto/into older cores. Age gradients are sharp, and no Pb diffusion gradients are observed. As U-Pb discordance in crystalline, non-radiation damaged grains is caused by diachronous, heterochemical mineral generations, interpretations of mineral ages, based on the exclusive role of diffusion, are superseded, and closure temperatures of zircon and monazite are irrelevant in geological reality. Other isotopic systems (Rb-Sr, K-Ar) were believed, since the 1960s, to be similarly controlled by the diffusivity of radiogenic daughters. When zircon and monazite discordance were recognized as zone accretion/reaction with sharp boundaries that showed little or no high-temperature diffusive re-equilibration, the other chronometric systems were left behind, and interpretations of mineral ages based on the exclusive role of diffusion survived. The evidence from textural-petrologic imaging (CL, BSE) and element mapping by electron probe microanalyzer (EPMA) or high spatial resolution SIMS or LA-ICP-MS provides the decisive constraints. All microcline and mica geochronometers that have been characterized in detail document patchy textures and evidence for mineral replacement reactions. It is important not to confuse causes and effects; hetero-chemical microstructures are not the cause of Ar and Sr loss; rather, they follow it. Ar and Sr loss by dissolution of the older mineral generation occurs first, heterochemical textures form later, when the replacive assemblage recrystallizes. Heterochemical mineral generations are identified and dated by their Ca/Cl/K systematics in 39Ar-40Ar. Replacive reactions adding or removing Cl, such as, e.g., sericite overgrowths on K-feldspar, retrograde muscovite intergrowths with phengite, etc. are detected by Cl/K vs. Ar/K isotope correlation diagrams. Ca-poor reaction products, such as, e.g., young biotite intergrown with older amphibole, adularia replacing microcline, etc., can be easily identified by Ca/K vs. Ar/K diagrams supported by EPMA analyses. Mixed mineral generations are observed to be the cause of discordant, staircase-shaped age spectra, while step-heating of crystals with age gradients produces concordant plateaus. Age gradients are therefore unrelated to staircase age spectra. There is a profound analogy between the U-Pb, Rb-Sr, and K-Ar systems. Pb and Ar diffusion rates are both much slower than mineral replacement rates for all T < 750 °C. Patchy retrogression textures are always associated with heterochemical signatures (U/Th ratios, REE patterns, Ca/Cl/K ratios). As a rule, single-generation minerals with low amounts of radiation damage give concordant ages, whereas discordance is caused by mixtures of heterochemical, resolvably diachronous, mineral generations in petrologic disequilibrium. This can also include (sub-)grains that have accumulated significant amounts of radiation damage. For accurate geochronology the petrologic characterization with the appropriate technique(s) of the minerals to be dated, and the petrologic context at large, are as essential as the mass spectrometric analyses.
DS1989-1559
1989
Villalobos, J.Villalobos, J.Bolivia's strategy for restructuring the state's mining sector and promoting private investment in miningNatural Resources forum, Vol. 13, No. 3, August pp. 191-197BoliviaMining investment, Economics
DS201212-0757
2012
Villamaire, M.Villamaire, M., Darbyshire, F.A., Bastow, I.D.3D mantle structure of the eastern Canadian shield and northeastern Appalachians from P-wave travel time tomography.Earth and Planetary Science Letters, in preparationCanadaTomography
DS201012-0791
2010
Villanova, C.Torro, L., Villanova, C., Castillo, M., Campeny, M., Goncalves, O.A., Melgarejo, J.C.Nb and REE minerals from the Virulundo carbonatite Namibe, Angola.International Mineralogical Association meeting August Budapest, abstract p. 578.Africa, AngolaCarbonatite
DS201212-0732
2012
Villanova, C.Torro, L., Villanova, C., Castillo, M., Campeny, M., Goncalves, A.O., Melgarejo, J.C.Niobium and rare earth minerals from the Virulundo carbonatite, Namibe, Angola.Mineralogical Magazine, Vol. 76, 2, pp. 393-409.Africa, AngolaDeposit - Virulundo
DS201906-1351
2019
Villanova de Benevent, C.Smith, M.P., Estrade, G., Marquis, E., Goodenough, K., Nason, P., Xu, C., Kynicky, J., Borst, A.M., Finch, A.A., Villanova de Benevent, C.Ion adsorption deposits: a comparison of deposits in Madagascar and China.3rd International Critical Metals Meeting held Edinburgh, 1p.abstract p. 53.Africa, Madagascar, ChinaREE

Abstract: Link to presentation pdf.
DS1984-0517
1984
Villar, L.Meyer, H.O.A., Villar, L.An Alnoite in the Sierras Subandinas Northern ArgentinaJournal of GEOLOGY, Vol. 92, No. 6, NOVEMBER PP. 741-751.GlobalAlnoite
DS1985-0444
1985
Villar, L.M.Meyer, H.O.A., Villar, L.M.Alnoite in the Sierras Subandinas, Northern ArgentinaGeological Society of America (GSA), Vol. 17, No. 3, P. 167. (abstract.).South America, ArgentinaPerovskite, Mineral Chemistry
DS1996-1481
1996
Villar, L.M.Villar, L.M., Escayola, M.P.Metallogenic aspects of ophiolites and other types of mafic and ultramafic complexes of ArgentinaGsn Proceedings Geol. Ore Dep. American Cordillera, Vol. 3, pp. 1487-99ArgentinaMetallogeny, Ophiolites
DS200612-1484
2005
Villard, R.Villard, R.The search for diamond worlds. Some planets may be made of diamonds - and could survive anything the universe throws at them.Astronomy, Kalmbach Publishing Co., Vol. 33, 11, pp. 42-45.GlobalTechnology
DS200912-0145
2009
Villas, R.N.N.Dall'Agnol, R., Fuck, R.A., Villas, R.N.N.Insights on the magmatism, crustal evolution and metallogenesis of the Amazonian craton.Journal of South American Earth Sciences, Vol. 27, 2-3, pp. 109-112.South America, BrazilMagmatism
DS1998-1569
1998
Villas-Boas, R.Wasserman, J.C., Siva-Filho, E.V., Villas-Boas, R.Environmental Geochemistry in the tropicsSpringer, 300pBrazil, ColombiaBook - table of contents, Geochemistry - tropical soils
DS1986-0840
1986
Villaseca, C.Villaseca, C., De la Nuez, J.Camptonite dikes in the Spanish central system *SPAEstudios Geologicos (Madrid)*SPA., Vol. 42, No. 2-3, pp. 690-77GlobalBlank
DS200812-0830
2008
Villaseca, C.Orejana, D., Villaseca, C., Billstrom, K., Patterson, B.Petrogenesis of Permian alkaline lamprophyres and diabases from the Spanish Central System and their geodynamic context within western Europe.Contributions to Mineralogy and Petrology, Vol. 156, 4, pp. 477-500.EuropeLamprophyre
DS200812-0831
2007
Villaseca, C.Orejana, D., Villaseca, C., Paterson, B.A.Geochemistry of mafic phenocrysts from alkaline lamprophyres of the Spanish Central System: implications on crystal fractionation, magma mixing...European Journal of Mineralogy, Vol. 19, no. 6, pp. 817-832.Europe, SpainXenoliths - magma chambers
DS201012-0622
2010
Villasenor, A.Replumaz, A., Negredo, A.M., Villasenor, A., Guillot, S.Indian continental subduction and slab break off during Tertiary collision.Terra Nova, Vol. 22, pp. 290-296.IndiaSubduction
DS201212-0758
2012
Villemaire, M.Villemaire, M., Darbyshire, F.A., Bastow, I.D.P wave tomography of eastern North America: evidence for mantle evolution from Archean to Phanerozoic, and modification during subsequent hotspot tectonism.Journal of Geophysical Research, Vol. 117, B12302, 15p.Mantle, North America, CanadaTomography, plumes
DS2002-1264
2002
Villemant, B.Pilet, S., Hernandez, J., Villemant, B.Evidence for high silicic melt circulation and metasomatic events in the mantle beneath alkaline provinces: the Na Fe augitic green core pyroxenes.Mineralogy and Petrology, Vol. 76, 1-2, pp.39-62.French Massif CentralTertiary alkali basalts
DS2002-1265
2002
Villemant, B.Pilot, S., Hernadez, J., Villemant, B.Evidence for high silicic melt circulation and metasomatic events in the mantle beneath alkaline provinces: the Na Fe augitic green core pyroxenes...Mineralogy and Petrology, Vol. 76, No. 1-2, pp. 39-62.French Massif CentralTertiary alkali basalts - Cantal Massif
DS200712-0402
2007
Villemant, B.Halama, R., Joron, J-L., Villemant, B., Markl, G., Treuil, M.Trace element constraints on mantle sources during mid-Proterozoic magmatism: evidence for a link between Gardar and Abitibi mafic rocks.Canadian Journal of Earth Sciences, Vol. 44, 4, pp. 459-478.Canada, Quebec, Europe, GreenlandMagmatism
DS1988-0070
1988
Villeneurve, M.Bonvalot, S., Villeneurve, M., Legeley, A., Albouy, Y.Leve gravimetrique du sud-ouest du craton Ouest -Africain.(in French)C.r. Academy Of Science Paris, Vol. 307, ser. II, pp. 1863-1868GlobalGeophysics-gravity, Tectonics
DS2000-0751
2000
VilleneuvePehrsson, S.J., Chacko, T., Pilkington, M., VilleneuveAnton terrane revisited: Late Archean exhumation of a moderate pressure granulite terrane in western SlaveGeology, Vol. 28, No. 12, Dec. pp. 1075-78.Northwest TerritoriesAnton terrane, Tectonic denudation
DS1994-0340
1994
Villeneuve, D.Corbeil, R., Villeneuve, D.Rapport sur les travaux d'exploration effectues sur l'ensemble des proprietes du project diamant II. DiabexQuebec Department of Mines, GM 52874, 336p.QuebecExploration - assessment, Diabex, Region de Miquelon et de Matagami
DS202011-2033
2020
Villeneuve, J.Casola, V., France, L., Galy, A., Bouden, N., Villeneuve, J.No evidence for carbon enrichment in the mantle source of carbonatites in eastern Africa.Geology, Vol. 48, 10, pp. 971976. pdfAfrica, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Carbonatites are unusual, carbon-rich magmas thought to form either by the melting of a carbon-rich mantle source or by low-degree partial melting of a carbon-poor (<80 ppm C) mantle followed by protracted differentiation and/or immiscibility. Carbonate-bearing mantle xenoliths from Oldoinyo Lengai (East African Rift), the only active volcano erupting carbonatites, have provided key support for a C-rich mantle source. Here, we report unique microscale O and C isotopic analyses of those carbonates, which are present as interstitial grains in the silicate host lava, veins in the xenoliths, and pseudo-inclusions in olivine xenoliths. The ?18O values vary little, from 19‰ to 29‰, whereas ?13C values are more variable, ranging from -23‰ to +0.5‰. We show that such carbonate ?18O values result from the low-temperature precipitation of carbonate in equilibrium with meteoric water, rather than under mantle conditions. In this framework, the observed ?13C values can be reproduced by Rayleigh distillation driven by carbonate precipitation and associated degassing. Together with petrological evidence of a physical connection between the three types of carbonates, our isotopic data support the pedogenic formation of carbonates in the studied xenoliths by soil-water percolation and protracted crystallization along xenolith cracks. Our results refute a mechanism of C enrichment in the form of mantle carbonates in the mantle beneath the Natron Lake magmatic province and instead support carbonatite formation by low-degree partial melting of a C-poor mantle and subsequent protracted differentiation of alkaline magmas.
DS202012-2210
2020
Villeneuve, J.Casola, V., France, L., Galy, A., Bouden, N., Villeneuve, J.No evidence for carbon enrichment in the mantle source of carbonatites in eastern Africa.Geology, Vol. 48, 10, 5p. PdfAfrica, Tanzaniacarbonatites

Abstract: Carbonatites are unusual, carbon-rich magmas thought to form either by the melting of a carbon-rich mantle source or by low-degree partial melting of a carbon-poor (<80 ppm C) mantle followed by protracted differentiation and/or immiscibility. Carbonate-bearing mantle xenoliths from Oldoinyo Lengai (East African Rift), the only active volcano erupting carbonatites, have provided key support for a C-rich mantle source. Here, we report unique microscale O and C isotopic analyses of those carbonates, which are present as interstitial grains in the silicate host lava, veins in the xenoliths, and pseudo-inclusions in olivine xenoliths. The ?18O values vary little, from 19‰ to 29, whereas ?13C values are more variable, ranging from -23‰ to +0.5‰. We show that such carbonate ?18O values result from the low-temperature precipitation of carbonate in equilibrium with meteoric water, rather than under mantle conditions. In this framework, the observed ?13C values can be reproduced by Rayleigh distillation driven by carbonate precipitation and associated degassing. Together with petrological evidence of a physical connection between the three types of carbonates, our isotopic data support the pedogenic formation of carbonates in the studied xenoliths by soil-water percolation and protracted crystallization along xenolith cracks. Our results refute a mechanism of C enrichment in the form of mantle carbonates in the mantle beneath the Natron Lake magmatic province and instead support carbonatite formation by low-degree partial melting of a C-poor mantle and subsequent protracted differentiation of alkaline magmas.
DS1991-0981
1991
Villeneuve, J.C.Lesquer, A., Villeneuve, J.C., Bronner, G.Heat flow dat a from the western margin of the West African craton(Mauritania)Physics of the Earth and Planetary Interiors, Vol. 66, pp. 320-329GlobalHeat flow, Craton
DS1980-0340
1980
Villeneuve, M.Villeneuve, M.Schema Geologique du Nord de la GuineeBulletin. SOC. GEOL. FRAN., SUPPL. French Geological Survey (BRGM) F 15, Vol. 22, No. 2, PP. 54-57.West Africa, GuineaProterozoic, Orogeny, Structure, Tectonics, Hercynien, Caledonia
DS1981-0420
1981
Villeneuve, M.Villeneuve, M.Resultats Preliminaires D'une Etude Geologique au Sud du Fouta Djalon.Comptes Rendus Somm. Seances Soc. Geol. Afrique., No. 2, PP. 55-59.West Africa, GuineaStructure, Tectonics, Basement, Petrology
DS1982-0503
1982
Villeneuve, M.Ponsard, J.F., Lesquer, A., Villeneuve, M.Une Suture Panafricaine sur la Bordure Occidentale du Craton Ouest Africain.Comptes Rendus Seances Academy of Science Ser. 2, Mec. Phys. Chim. S, Vol. 295, No. 13, PP. 1161-1164.West Africa, Guinea, Sierra Leone, Mali, GermanyTectonics
DS1982-0620
1982
Villeneuve, M.Villeneuve, M.Schema Lithostratigraphique des Mauritanides au Sud du Senegal et au Nord de la Guinee D'apres Les Donnees Actuelles.Geological Society FR. Bulletin., Vol. 24, No. 2, PP. 249-254.West Africa, Guinea, SenegalTectonic, Structure, Orogeny, Caledonian, Hercynien
DS1987-0133
1987
Villeneuve, M.Dallmeyer, R.D., Villeneuve, M.40Ar/39ar mineral age record of polyphase tectonothermal evolution in the southern Mauritanide orogen, southeastern SenegalGeological Society of America (GSA) Bulletin, Vol. 98, No. 5, May pp. 602-611GlobalWest Africa, Craton
DS1987-0762
1987
Villeneuve, M.Vauchez, A., Kessler, S.F., Lecorche, J.P., Villeneuve, M.Southward extrusion tectonics during the Carboniferous Africa-North American collisionTectonophysics, Vol. 142, No. 2-4, November 1, pp. 317-322South AfricaTectonics
DS1989-0666
1989
Villeneuve, M.Housh, T., Bowring, S.A., Villeneuve, M.Lead isotopic study of Early Proterozoic Wopmay Orogen, northwest Canada: role of continental crust in arc magmatismJournal of Geology, Vol. 97, No. 6, November pp. 735-748Northwest TerritoriesGeochronology, Orogeny -Wopmay
DS1989-1179
1989
Villeneuve, M.Pasteels, P., Villeneuve, M., De Paepe, P., Klerkx, J.Timing of volcanism of the southern Kivu province:implications for the evolution of the western branch of the East African Rift systemEarth and Planetary Science Letters, Vol. 94, No. 3/4 September pp.353-363East AfricaTectonics, Rift
DS1990-1519
1990
Villeneuve, M.Villeneuve, M.Structure and evolution of the Panafrican II basins in the western part Of the West African craton.(in French)Bulletin. Soc. Geol. de France, (in French), Vol. 6, No. 1, Jan-Feb. pp. 155-166West AfricaCraton, Structure
DS1991-0148
1991
Villeneuve, M.Bonvalot, S., Villeneuve, M., Albouy, Y.Gravity dat a interpretation in Sierra Leone- evidence of collision suture in the Rokelides Pan-African orogenic belt.(in French)Comptes Rendus de l'Academie des Sciences Serie II, Vol. 312, No. 8, April pp. 841-848Sierra LeoneGeophysics -gravity, Tectonics
DS1991-1804
1991
Villeneuve, M.Villeneuve, M., Cornee, J.J.Evolution paleogeographique de la marge nord ouest de l'Afrique du Cambiena la fin du Carbonifere.Canadian Journal of Earth Sciences, Vol. 28, pp. 1121-30.GlobalWest African Craton, Paleogeography
DS1993-1668
1993
Villeneuve, M.Villeneuve, M.The West African fold belts: structure and evolutionComptes Rendus Science Paris, Tomb. 316, Serie II, pp. 411-417.GlobalStructure, Birrimian, Guyana shield, Bassarides Orogeny
DS1993-1669
1993
Villeneuve, M.Villeneuve, M.Preliminary geochronological results from the Winter Lake Lac de Gras SlaveProvince, NATMAP project.Geological Survey of Canada Paper, No. 93-2, pp. 29-38.Northwest TerritoriesGeochronology, Lac de Gras area
DS1993-1670
1993
Villeneuve, M.Villeneuve, M., Ross, Theriault, Miles, Parrish, BroomeTectonic subdivision and uranium-lead (U-Pb) geochronology of the crystalline basement Of the Alberta basin.Geological Survey of Canada (GSC), Bulletin. No. 447, 86p.Alberta, Western CanadaTectonics, Geochronology
DS1994-1444
1994
Villeneuve, M.Reif, C., Villeneuve, M., Helmstaedt, H.Discovery of an Archean carbonatite bearing alkaline complex in northern Slave Province: tectonic economicsNorthwest Territories 1994 Open House Abstracts, p. 53-54. abstractNorthwest TerritoriesCarbonatite
DS1994-1859
1994
Villeneuve, M.Villeneuve, M.Ages of detrital zircon from supracrustal sequences in the Slave Province:implications for age of basement.Northwest Territories 1994 Open House Abstracts, p. 60. abstractNorthwest TerritoriesGeochronology, Slave Craton
DS1998-0247
1998
Villeneuve, M.Chiarenzelli, J., Aspler, L., Villeneuve, M., Lewry, J.Early Proterozoic evolution of the Saskatchewan Craton and its allochthonous cover, Trans-Hudson OrogenJournal of Geology, Vol. 106, No. 3, May pp. 247-267SaskatchewanCraton - Glennie Domain, Geochronology
DS1998-1258
1998
Villeneuve, M.Ross, G.M., Theriault, R., Villeneuve, M.Buffalo Head Terrane and Buffalo Head Craton: what's the difference and does it matter?Calgary Mining Forum, Apr. 8-9, p. 19-20. abstractAlbertaGeochronology, Craton, subduction
DS1999-0677
1999
Villeneuve, M.Skulski, T., Villeneuve, M.Geochronological compilation of the Rae and Hearne provinces: northwest Saskatchewan and Alberta.Geological Survey of Canada (GSC), Open file D3706 $ 20.00Northwest Territories, Saskatchewan, AlbertaGeochronology, Rae, Hearne
DS1999-0678
1999
Villeneuve, M.Skulski, T., Villeneuve, M.Geochronological compilation of the Superior ProvinceGeological Survey of Canada (GSC) Open File, No. 3715Ontario, QuebecGeochronology
DS200712-0242
2006
Villeneuve, M.Deynoux, M., Affaton, P., Trompette, R., Villeneuve, M.Pan-African tectonic evolution and glacial events registered in Neoproterozoic to Cambrian cratonic and foreland basins of West Africa.Journal of African Earth Sciences, Vol. 46, 5, Dec. pp. 397-426.Africa, West AfricaTectonics
DS201012-0077
2010
Villeneuve, M.Buchan, K.L., Ernst, R.E., Bleeker, W., Davis, W.J., Villeneuve, M., Van Breeman, O., Hamilton, SoderlundMap of Proterozoic magmatic events in the Slave Craton, Wopmay Orogen and environs, Canadian Shield.International Dyke Conference Held Feb. 6, India, 1p. AbstractCanada, Northwest TerritoriesMagmatism
DS1989-1305
1989
Villeneuve, M.E.Ross, G.M., Villeneuve, M.E., Parrish, R.R., Bowring, S.Tectonic subdivision and uranium-lead (U-Pb) geochronology of the Precambrian basement Alberta Basin, Western Canada.Geological Survey of Canada (GSC) Open file, No. 2103, 1:1, 000, 000Alberta, CordilleraGeochronology, Tectonics
DS1989-1560
1989
Villeneuve, M.E.Villeneuve, M.E., Walker, D.A.Heavy minerals: detection and classification using automated image and x-ray microanalysisGeological Society of Canada (GSC) Forum 1989, P. 23 abstractGlobalSpectrometry, Heavy minerals
DS1990-1520
1990
Villeneuve, M.E.Villeneuve, M.E., LeCheminant, A.N.Kimzeyite (Zr-garnet) from alnoites at Ile Bizard and Oka Quebec:mineralogy and petrogenesisGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Vancouver 90 Program with Abstracts, Held May 16-18, Vol. 15, p. A135. AbstractQuebecAlnoite, Mineralogy
DS1991-1460
1991
Villeneuve, M.E.Ross, G.M., Parrish, R.R., Villeneuve, M.E., Bowring, R.D.Geophysics and geochronology of the crystalline basement of the AlbertaBasin, western CanadaCanadian Journal of Earth Sciences, Vol. 28, No. 4, April pp. 512-522AlbertaGeophysics -magnetics, Basement tectonics, Geochronology
DS1993-1671
1993
Villeneuve, M.E.Villeneuve, M.E., Barrie, C.T., et al.U-Ob ages from Hepburn Island and Winter Lake-Lac de Gras NATMAP northern and central Slave Province, N.W.T.Geological Society of Canada (GSC) Forum abstracts, p. 19. poster abstract.Northwest TerritoriesGeochronology, Regional
DS1994-0787
1994
Villeneuve, M.E.Hrabi, R.B., Grant, J.W., Berclaz, A., Duquette, D., Villeneuve, M.E.Geology of the northern half of the Winter Lake supracrustal belt, SlaveProvince, Northwest Territories.Geological Survey of Canada Current Research, No. 1994, C, pp. 13-22.Northwest TerritoriesGeology, Winter Lake
DS1994-1860
1994
Villeneuve, M.E.Villeneuve, M.E., Van Breemen, O.A compilation of uranium-lead (U-Pb) age dat a from the Slave ProvinceGeological Survey of Canada Open file, No. 2972, 53p.Northwest TerritoriesGeochronology, Slave Province
DS1996-1174
1996
Villeneuve, M.E.Reif, C., Villeneuve, M.E.Carbonatites and conglomerates Late Archean extension across the SlaveProvince.Geological Association of Canada (GAC) Annual Abstracts, Vol. 21, abstract only p.A79.Northwest TerritoriesCarbonatite, Tectonics
DS1997-1211
1997
Villeneuve, M.E.Villeneuve, M.E., Henderson, J.R., Hrabi, R.B., Jackson2.80-2.58 Ga plutonism and volcanism in the Slave ProvinceGeological Survey of Canada (GSC) Paper, No. 1997-F, pp. 37-60.Northwest TerritoriesGeochronology, Craton - Slave
DS1997-1212
1997
Villeneuve, M.E.Villeneuve, M.E., Henderson, J.R., Hrabi, R.B., Jackson2.70 - 2.58 Ga plutonism and volcanism in the Slave Province, District ofMackenzie, Northwest Territories.Geological Society of Canada (GSC) Paper, No. 1997-F, p. 37-60.Northwest TerritoriesGeochronology, Magma activity
DS1997-1213
1997
Villeneuve, M.E.Villeneuve, M.E., Relf, C.Temporal coincidence of Wide spread Archean carbonatite intrusion and granite magmatism in the Slave Province.Geological Association of Canada (GAC) Abstracts, Northwest TerritoriesCarbonatite, Magmatism
DS1998-1546
1998
Villeneve, M.E.Villeneve, M.E., Reif, C.Tectonic setting of 2.6 Ga carbonatites in the Slave Province, northwestCanada.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 1975-86.Northwest TerritoriesCarbonatite, Tectonics
DS1991-1805
1991
Villeurbanne, J.V.Villeurbanne, J.V., Von Roermund, H., Lardeaux, J-M.The clinopyroxene/plagioclase symplectite in retrograde eclogites: a potential geothermobarometerGeologische Rundschau, Vol. 80, No. 2, pp. 303-320GlobalEclogites, Petrology
DS1991-1916
1991
Villieras, F.Yvon, J., Marion, P., Michot, L., Villieras, F., Wagner, F.E.Development of mineralogy applications in mineral processingEur. Journal of Mineral, Vol. 3, No. 4, pp. 667-676GlobalMineral processing, overview
DS201012-0585
2009
Villiger, S.Pilet, S., Ulmer, P., Villiger, S.Liquid line of descent of a basanitic liquid at 1.5 Gpa: constraints on the formation of metasomatic veins.Contributions to Mineralogy and Petrology, In press formatted available 23p.TechnologyMetasomatism
DS2002-1669
2002
Villinger, H.Villinger, H., Grevemeyer, I., Kaul, N., Hauschild, J., Pfender, M.Hydrothermal heat flux through aged oceanic crust: where does the heat escape?Earth and Planetary Science Letters, Vol. 202, 1, pp.159-170.MantleGeothermometry
DS1993-1672
1993
Vilotte, J.F.Vilotte, J.F., et al.Lithosphere rheology and sedimentary basinsTectonophysics, Special issue The origin of sedimentary basins:inferences, pp. 89-96GlobalBasin, Tectonics
DS1992-0248
1992
Vilotte, J.P.Chery, J., Lucazeau, F., Daignieres, M., Vilotte, J.P.Large uplift of rift flanks: a genetic link with lithospheric rigidity?Earth and Planetary Science Letters, Vol. 112, pp. 195-212Red Sea, Rhine, East Africa, Baikal, RussiaMantle structure MRDU, Rifting
DS1997-0737
1997
Vilpas, L.Marmo, J., Vilpas, L., Chernet, T., Nenonen. K.Study of the kimberlitic indicator minerals in Quaternary samples, eastern and northern Finland.Papunen: 4th. Biennial SGA Meeting, pp. 775-777.FinlandDiamond exploration, Geomorphology, till, esker sampling, geochemistry
DS2001-0931
2001
Vincent, A.P.Piromallo, C., Vincent, A.P., Yuen, D.A., Morelli, A.Dynamics of the transition zone under Europe inferred from wavelet cross spectra of seismic tomography.Physics of the Earth and Planetary Interiors, Vol. 125, No. 1-4, pp. 125-39.EuropeGeophysics - seismics
DS200612-0561
2006
Vincent, A.P.Heir Majumder, C.A., Travis, B.J., Belanger, E., Richard, G., Vincent, A.P., Yuen, D.A.Efficient sensitivity analysis for flow and transport in the Earth's crust and mantle.Geophysical Journal International, Vol. 166, 2, pp. 907-922.MantleGeophysics - seismics
DS1994-1174
1994
Vincent, K.R.Merritts, D.J., Vincent, K.R., Wohl, E.E.Long river profiles, tectonism and eustasy: a guide to interpreting fluvial terraces.Journal of Geophysical Research, Vol. 99, No. B7, July 10, pp. 14, 031-51.CaliforniaGeomorphology -not specific to diamonds, Terraces -fluvial
DS1990-1232
1990
Vincent, P.Rivard, L., Turner, A.M., Ryerson, R.A., Vincent, P.Land use mapping with thematic mapper imagery: a Canadian perspectiveGeocarto International, No. 1, 1990, pp. 33-50CanadaRemote Sensing, Thematic mapper -overview
DS201805-0989
2018
Vincente de Gouveia, S.Vincente de Gouveia, S., Besse, J., Frizon de Lamotte, D., Greff-Lefftz, M., Lescanne, M., Gueydan, F., Leparmentier, F.Evidence of hot spot paths below Arabia and the Horn of Africa and consequences on the Red Sea opening.Earth Planetary Science Letters, Vol. 487, pp. 210-220.Africatectonics

Abstract: Rifts are often associated with ancient traces of hotspots, which are supposed to participate to the weakening of the lithosphere. We investigated the expected past trajectories followed by three hotspots (Afar, East-Africa and Lake-Victoria) located around the Red Sea. We used a hotspot reference frame to compute their location with respect to time, which is then compared to mantle tomography interpretations and geological features. Their tracks are frequently situated under continental crust, which is known to strongly filter plume activity. We looked for surface markers of their putative ancient existence, such as volcanism typology, doming, and heat-flow data from petroleum wells. Surface activity of the East-Africa hotspot is supported at 110 Ma, 90 Ma and 30 Ma by uplift, volcanic activity and rare gas isotopic signatures, reminiscent of a deep plume origin. The analysis of heat-flow data from petroleum wells under the Arabian plate shows a thermal anomaly that may correspond to the past impact of the Afar hotspot. According to derived hotspot trajectories, the Afar hotspot, situated (at 32 Ma) 1000 km north-east of the Ethiopian-Yemen traps, was probably too far away to be accountable for them. The trigger of the flood basalts would likely be linked to the East-Africa hotspot. The Lake-Victoria hotspot activity appears to have been more recent, attested only by Cenozoic volcanism in an uplifted area. Structural and thermal weakening of the lithosphere may have played a major role in the location of the rift systems. The Gulf of Aden is located on inherited Mesozoic extensional basins between two weak zones, the extremity of the Carlsberg Ridge and the present Afar triangle, previously impacted by the East-Africa hotspot. The Red Sea may have opened in the context of extension linked to Neo-Tethys slab-pull, along the track followed by the East Africa hotspot, suggesting an inherited thermal weakening.
DS1998-0332
1998
Vincenzi, E.P.De, S., Heaney, P.J., Vincenzi, E.P., Hargraves, R.B.Microstructural comparison between natural polycrystalline diamond -carbonado and artificial..Ima 17th. Abstract Vol., p. A16. poster abstractBrazil, Central African RepublicCarbonado, Diamond synthesis
DS201112-0695
2011
Vinciguerra, S.Mollo, S., Vinciguerra, S., Lezzi, G., Iarocci, A., Scarlato, P., Heap, M.J., Dingwell, D.B.Volcanic edifice weakening via devolatization reactions.Geophysical Journal International, In press, availableMantleVolcanism - not specific to diamonds
DS200712-0108
2007
VinczeBrenker, F.E., Vollmer, Vincze, Vekemans, Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200512-0113
2005
Vincze, L.Brenker, F.E., Vincze, L., Velemans, Nasdala, Stachel, Vollmer, Kersten, Somogyi, Adams, Joswig, HarrisDetection of a Ca rich lithology in the Earth's deep ( >300km) convecting mantle.Earth and Planetary Science Letters, Vol. 236, 3-4, pp. 579-587.Africa, GuineaKankan, diamond inclusions, spectroscopy
DS200612-0171
2006
Vincze, L.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, A., Janssens, K., Szaloki, I., Nasdala, L., Joswig, W., Kaminsky, F.CO2 recycling to the deep convecting mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleConvection
DS200712-0106
2007
Vincze, L.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200712-0107
2007
Vincze, L.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS201112-0961
2011
Vincze, L.Silversmit, G., Vekemans, B., Appel, K., Schmitz, S., Schoonjans, T., Brenker, F.E., Kaminsky, F., Vincze, L.Three dimensional Fe speciation of an inclusion cloud within an ultradeep diamond by confocal u-x-ray absortion near edge structure: evidence for late stageAnalytical Chemistry, Vol. 83, pp. 6294-6299.South America, Brazil, Mato GrossoJuina, Rio Soriso, diamond overprint
DS201412-0669
2014
Vincze, L.Pearson, D.G., Brenker, F.E., Nestola, F., McNeill, J., Nasdala, L., Hutchinson, M.T., Mateev, S., Mather, K., Silversmit, G., Schmitz, S., Vekemans, B., Vincze, L.Hydrous mantle transition zone indicated by ring woodite included in diamond.Nature, Vol. 507, March 13, pp. 221-224.Mantle, South America, Brazil, Mato GrossoDiamond inclusion - water storage capacity, magmatism
DS201412-0668
2014
Vinczw=e, L.Pearson, D.G., Brenker, F., Nestola, F., McNeil, J., Nasdala, L., Hutchison, M., Mateev, S., Mather, K., Silversmit, G., Schmitz, S., Vekemans, B., Vinczw=e, L.A hydrous mantle transition zone indicated by ring woodite included within diamond.Goldschmidt Conference 2014, 1p. AbstractMantleDiamond inclusion
DS201805-0933
2018
Vind, A.K.Asthana, D., Kumar, S., Vind, A.K., Zehra, F., Kumar, H., Pophare, A.M.Geochemical fingerprinting of ~2.5 Ga forearc-arc-backarc related magmatic suites in the Bastar Craton, central India.Journal of Asian Earth Sciences, Vol. 157, pp. 218-234.IndiaCraton

Abstract: The Pitepani volcanic suite of the Dongargarh Supergroup, central India comprises of a calc-alkaline suite and a tholeiitic suite, respectively. The rare earth element (REE) patterns, mantle normalized plots and relict clinopyroxene chemistry of the Pitepani calc-alkaline suite are akin to high-Mg andesites (HMA) and reveal remarkable similarity to the Cenozoic Setouchi HMA from Japan. The Pitepani HMAs are geochemically correlated with similar rocks in the Kotri-Dongargarh mobile belt (KDMB) and in the mafic dykes of the Bastar Craton. The rationale behind lithogeochemical correlations are that sanukitic HMAs represent fore-arc volcanism over a very limited period of time, under abnormally high temperature conditions and are excellent regional and tectonic time markers. Furthermore, the tholeiitic suites that are temporally and spatially associated with the HMAs in the KDMB and in the mafic dykes of the Bastar Craton are classified into: (a) a continental back-arc suite that are depleted in incompatible elements, and (b) a continental arc suite that are more depleted in incompatible elements, respectively. The HMA suite, the continental back-arc and continental arc suites are lithogeochemically correlated in the KDMB and in the mafic dykes of the Bastar Craton. The three geochemically distinct Neoarchaean magmatic suites are temporally and spatially related to each other and to an active continental margin. The identification of three active continental margin magmatic suites for the first time, provides a robust conceptual framework to unravel the Neoarchaean geodynamic evolution of the Bastar Craton. We propose an active continental margin along the Neoarchaen KDMB with eastward subduction coupled with slab roll back or preferably, ridge-subduction along the Central Indian Tectonic Zone (CITZ) to account for the three distinct magmatic suites and the Neoarchean geodynamic evolution of the Bastar Craton.
DS1991-0836
1991
Vine, F.J.Kearey, P., Vine, F.J.Global tectonics. Reference textOxford University of Press, 320pGlobalTectonics -global
DS1995-0642
1995
Vine, F.J.Glover, P.W.J., Vine, F.J.Beyond KTB -electrical conductivity of the deep continental crustSurveys in Geophysics, Vol. 16, pp. 5-36MantleGeophysics -seismics, Conductivity
DS1995-0643
1995
Vine, F.J.Glover, P.W.J., Vine, F.J.Beyond KTB -electrical conductivity of the deep continental crustSurveys in Geophysics, Vol. 16, pp. 5-36.Mantle, crustGeophysics, Magneto -telluric (MT) methods
DS1995-0922
1995
Vine, F.J.Kearey, P., Vine, F.J.Global tectonicsBlackwell Scientific, GlobalBook -ad, Tectonics -revised edition
DS200912-0799
2008
Vines, A.Vines, A.Burning bright: India's tiger economy in Africa.Optima, Vol. 54, 1, Dec. pp. 46-57.Africa, IndiaEconomics
DS201708-1784
2017
Vines, M.Vines, M.Discovery of an orangeite magmatic event in the central Kalahari: implications for the origin of southern African kimberlites.11th. International Kimberlite Conference, PosterAfrica, South Africa, Botswanaorangeite
DS2003-1215
2003
Vinick, L.Saul, J., Vinick, L., Wookey, J., Kendall, J.M., Barruol, G.Mantle deformation or processing artefact?Nature, No. 6928, March 13, p. 136.MantleTectonics
DS1982-0621
1982
Vink, G.E.Vink, G.E.Continental Rifting and the Implications for Plate Tectonicreconstructions.Journal of Geophysical Research, Vol. 87, No. B 13, PP. L0677-L0, 688.GlobalMid-continent
DS1989-0087
1989
Vinnicehnko, T.G.Bartoshinskiy, Z.V., Bekesha, S.N., Vinnicehnko, T.G., Zudin, N.G.Gas admixtures in diamonds and garnets from kimberlites of the Daldyn-Alakit region in Yakutia.(Russian)Mineralogicheskiy Sbornik, (Russian), Vol. 43, No. 2, pp. 83-86Russia, YakutiaMineral chemistry
DS1992-0094
1992
Vinnicehnko, T.G.Bartoshinskiy, Z.V., Bekesha, S.N., Vinnicehnko, T.G.Photoluminescence sprecta of diamond from kimberlite pipes of the northern European Platform**RusL'vov University Of, (russian), Vol. 14, No. 3, pp. 25-30Russia, YakutiaArkhangelskgeol, Ore microscopy
DS1995-0114
1995
VinnichenkoBartoshinsky, Z.V., Bekesha, S.N., Vinnichenko, Zudin etGas impurities in diamonds and garnets from kimberlites of the Daldyn-Alakit region, Yakutia.Proceedings of the Sixth International Kimberlite Conference Almazy Rossii Sakha abstract, p. 20-22.Russia, YakutiaDiamond inclusions, Deposit -Sytykan, Udachnaya
DS1984-0142
1984
Vinnichenko, T.G.Bartoshinskiy, Z.V., Bekesha, S.N., Bilenko, YU.M., Vinnichenko, T.G.Distribution of natural diamonds based on their intensity ofluminescence.(Russian)Mineral. Sborn. (L'Vov), (Russian), Vol. 38, No. 2, pp. 25-27RussiaDiamond Morphology
DS1986-0056
1986
Vinnichenko, T.G.Bartoshinskiy, Z.V., Bekesha, S.N., Vinnichenko, T.G.Types of photoluminesence spectra of Yakutia diamond. (Russian)Mineral. Zhurnal., (Russian), Vol. 40, No. 1, pp. 32-38RussiaDiamond morphology, Luminesence
DS1986-0057
1986
Vinnichenko, T.G.Bartoshinskiy, Z.V., Bekesha, S.N., Vinnichenko, T.G., PidzyrailoTypes of photoluminescence spectra of diamonds of Yakutia.(Russian)Mineral. Sbov. (Lvov), (Russian), Vol. 40, No. 1, pp. 32-38RussiaSpectroscopy
DS1988-0044
1988
Vinnichenko, T.G.Bartoshinskii, Z.V., Bekesha, S.N., Vinnichenko, T.G.Relation between the degree of preservation Of kimberlite hosted diamond sand some opticalparameters.(Russian)Mineral. Sbornik (L'Vov), (Russian), Vol. 42, No. 1, pp. 8-13RussiaDiamond morphology
DS1990-0172
1990
Vinnichenko, T.G.Bartoshinskiy, Z.V., Bekesha, S.N., Verzhak, V.V., Vinnichenko, T.G.Non x-ray luminescence kimberlite diamonds.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 2, pp. 15-19RussiaDiamond morphology, Spectroscopy
DS2001-0515
2001
Vinnichuk, N.N.Ivanov, K.S., Vinnichuk, N.N.Geology of the Uralian gravity supermaximumDoklady Academy of Sciences, Vol. 377, No. 2, Feb-Mar. pp. 139-42.GlobalGeophysics - gravity
DS2002-1670
2002
Vinnick, L.Vinnick, L., Peregoudov, D., Makeyeva, L., Oreshin, S., Roecker, S.Towards 3 D fabric in the continental lithosphere and asthenosphere: the Tien ShanGeophysical Research Letters, Vol. 16, 39, Aug. 15, 10.1029/2001GL014588ChinaGeophysics - seismics
DS200712-1121
2006
Vinnick, L.Vinnick, L., Farra, V.S velocity reversal in the mantle transition zone.Geophysical Research Letters, Vol. 33, 18, Sept. 28, L18316MantleGeophysics - seismics
DS1995-1998
1995
Vinnick, L.P.Vinnick, L.P., Green, R.W.E., Nicolaysen, L.O.Recent deformation of the deep continental root beneath southern AfricaNature, Vol. 375, No. 6526, May 4, pp. 50-52.South Africa, BotswanaMantle, tectonics, Craton, root
DS200512-1145
2005
Vinnick, L.P.Vinnick, L.P., Foulger, G.R., Du,Z.Seismic boundaries in the mantle beneath Iceland: a new constraint on temperature.Geophysical Journal International, Vol. 160, 2, pp. 533-538.Europe, IcelandGeophysics - seismics
DS201609-1699
2016
Vinnick, L.P.Artemieva, I.M., Vinnick, L.P.Density structure of the cratonic mantle in southern Africa: 1. Implications for dynamic topography.Gondwana Research, in press available 13p.Africa, South AfricaCratonic lithosphere

Abstract: The origin of high topography in southern Africa is enigmatic. By comparing topography in different cratons, we demonstrate that in southern Africa both the Archean and Proterozoic blocks have surface elevation 500-700 m higher than in any other craton worldwide, except for the Tanzanian Craton. An unusually high topography may be caused by a low density (high depletion) of the cratonic lithospheric mantle and/or by the dynamic support of the mantle with origin below the depth of isostatic compensation (assumed here to be at the lithosphere base). We use free-board constraints to examine the relative contributions of the both factors to surface topography in the cratons of southern Africa. Our analysis takes advantage of the SASE seismic experiment which provided high resolution regional models of the crustal thickness. We calculate the model of density structure of the lithospheric mantle in southern Africa and show that it has an overall agreement with xenolith-based data for lithospheric terranes of different ages. Density of lithospheric mantle has significant short-wavelength variations in all tectonic blocks of southern Africa and has typical SPT values of ca. 3.37-3.41 g/cm3 in the Cape Fold and Namaqua-Natal fold belts, ca. 3.34-3.35 g/cm3 in the Proterozoic Okwa block and the Bushveld Intrusion Complex, ca. 3.34-3.37 g/cm3 in the Limpopo Belt, and ca. 3.32-3.33 g/cm3 in the Kaapvaal and southern Zimbabwe cratons.The results indicate that 0.5-1.0 km of surface topography, with the most likely value of ca. 0.5 km, cannot be explained by the lithosphere structure within the petrologically permitted range of mantle densities and requires the dynamic (or static) contribution from the sublithospheric mantle. Given a low amplitude of regional free air gravity anomalies (ca. + 20 mGal on average), we propose that mantle residual (dynamic) topography may be associated with the low-density region below the depth of isostatic compensation. A possible candidate is the low velocity layer between the lithospheric base and the mantle transition zone, where a temperature anomaly of 100-200 °C in a ca. 100-150 km thick layer may explain the observed reduction in Vs velocity and may produce ca. 0.5-1.0 km to the regional topographic uplift.
DS201609-1700
2016
Vinnick, L.P.Artemieva, I.M., Vinnick, L.P.Density structure of the cratonic mantle in southern Africa: 2. Correlations with kimberlite distribution, seismic velocities, and Moho sharpness.Gondwana Research, Vol. 36, pp. 14-27.Africa, South AfricaKimberlite

Abstract: We present a new regional model for the depth-averaged density structure of the cratonic lithospheric mantle in southern Africa constrained on a 30? × 30? grid and discuss it in relation to regional seismic models for the crust and upper mantle, geochemical data on kimberlite-hosted mantle xenoliths, and data on kimberlite ages and distribution. Our calculations of mantle density are based on free-board constraints, account for mantle contribution to surface topography of ca. 0.5-1.0 km, and have uncertainty ranging from ca. 0.01 g/cm3 for the Archean terrains to ca. 0.03 g/cm3 for the adjacent fold belts. We demonstrate that in southern Africa, the lithospheric mantle has a general trend in mantle density increase from Archean to younger lithospheric terranes. Density of the Kaapvaal mantle is typically cratonic, with a subtle difference between the eastern, more depleted, (3.31-3.33 g/cm3) and the western (3.32-3.34 g/cm3) blocks. The Witwatersrand basin and the Bushveld Intrusion Complex appear as distinct blocks with an increased mantle density (3.34-3.35 g/cm3) with values typical of Proterozoic rather than Archean mantle. We attribute a significantly increased mantle density in these tectonic units and beneath the Archean Limpopo belt (3.34-3.37 g/cm3) to melt-metasomatism with an addition of a basaltic component. The Proterozoic Kheis, Okwa, and Namaqua-Natal belts and the Western Cape Fold Belt with the late Proterozoic basement have an overall fertile mantle (ca. 3.37 g/cm3) with local (100-300 km across) low-density (down to 3.34 g/cm3) and high-density (up to 3.41 g/cm3) anomalies. High (3.40-3.42 g/cm3) mantle densities beneath the Eastern Cape Fold belt require the presence of a significant amount of eclogite in the mantle, such as associated with subducted oceanic slabs. We find a strong correlation between the calculated density of the lithospheric mantle, the crustal structure, the spatial pattern of kimberlites, and their emplacement ages. (1) Blocks with the lowest values of mantle density (ca. 3.30 g/cm3) are not sampled by kimberlites and may represent the "pristine" Archean mantle. (2) Young (< 90 Ma) Group I kimberlites sample mantle with higher density (3.35 ± 0.03 g/cm3) than the older Group II kimberlites (3.33 ± 0.01 g/cm3), but the results may be biased by incomplete information on kimberlite ages. (3) Diamondiferous kimberlites are characteristic of regions with a low-density cratonic mantle (3.32-3.35 g/cm3), while non-diamondiferous kimberlites sample mantle with a broad range of density values. (4) Kimberlite-rich regions have a strong seismic velocity contrast at the Moho, thin crust (35-40 km) and low-density (3.32-3.33 g/cm3) mantle, while kimberlite-poor regions have a transitional Moho, thick crust (40-50 km), and denser mantle (3.34-3.36 g/cm3). We explain this pattern by a lithosphere-scale (presumably, pre-kimberlite) magmatic event in kimberlite-poor regions, which affected the Moho sharpness and the crustal thickness through magmatic underplating and modified the composition and rheology of the lithospheric mantle to make it unfavorable for consequent kimberlite eruptions. (5) Density anomalies in the lithospheric mantle show inverse correlation with seismic Vp, Vs velocities at 100-150 km depth. However, this correlation is weaker than reported in experimental studies and indicates that density-velocity relationship in the cratonic mantle is strongly non-unique.
DS1996-0387
1996
VinnikDricker, I.G., Roecker, Kosarev, VinnikShear wave velocity structure of the crust mantle beneath the KolaPeninsula.Geophysical Research. Lett., Vol. 23, No. 22, Nov. 15, pp. 3389-92.Russia, Kola PeninsulaGeophysics - seismics, Structure
DS1992-1465
1992
Vinnik, L.Stammler, K., Kind, R., Petesen, N., Kosarev, G., Vinnik, L., LiuThe upper mantle discontinuities: correlated or anticorrelated?Geophysical Research Letters, Vol. 19, No. 15, August 3, pp. 1563-1566MantleDiscontinuity, Structure
DS1993-1224
1993
Vinnik, L.Petersen, N., Vinnik, L., Kosarev, G., Kind, R., Oreshin, S., Stummler, K.Sharpness of the mantle discontinuitiesGeophysical Research Letters, Vol. 20, No. 9, May 7, pp. 859-862.MantleGeophysics
DS1998-1103
1998
Vinnik, L.Oreshin, S., Vinnik, L., Kind, R.Subducted lithosphere or 530 km discontinuity?Geophysical Research Letters, Vol. 25, No. 7, Apr. 1, pp. 1091-94.MantleDiscontinuity, Boundary
DS1999-0178
1999
Vinnik, L.Dricker, I., Vinnik, L., Makeyeva, L.Upper mantle flow in eastern EuropeGeophysical Research Letters, Vol. 27, No. 9, May pp. 1219-22.EuropeGeophysics - seismics, Mantle flow, melting
DS2000-0938
2000
Vinnik, L.Stutzmann, E., Vinnik, L., Singh, S.Constraints on the S wave velocity at the base of the mantleGeophysical Research Letters, Vol. 27, No. 11, Jun. pp. 1571-4.MantleGeophysics - seismics
DS2002-1671
2002
Vinnik, L.Vinnik, L., Farra, V.Subcratonic low velocity layer and flood basaltsGeophysical Research Letters, Vol.29,4,pp. 9-1,-4.MantleBasalts, Geophysics - seismics
DS200712-1122
2007
Vinnik, L.Vinnik, L., Farra, V.Low S velocity atop the 410 km discontinuity and mantle plumes.Earth and Planetary Science Letters, Vol. 262, 3-4, Oct. 30, pp. 398-412.MantleGeophysics - seismics, hot spots
DS200712-1123
2007
Vinnik, L.Vinnik, L., Singh, A., Kiselev, S., Kumar, M.R.Upper mantle beneath foothills of the western Himalaya: subducted lithospheric slab or keel of the Indian Shield?Geophysical Journal International, Vol. 171, 3, Dec. pp. 1162-1171.AsiaIndia-Eurasia zone
DS200812-0573
2008
Vinnik, L.Kiselev, S., Vinnik, L., Oreshin, S., Gupta, S., Rai, S.S., Singh, A., Kumar, Mohan.Lithosphere of the Dharwar craton by joint inversion of P and S receiver functions.Geophysical Journal International, In press ( available)IndiaGeophysics - seismics
DS200912-0800
2009
Vinnik, L.Vinnik, L., Oreshin, S., Kosarev, G., Kiselev, S.,Makeyeva, L.Mantle anomalies beneath southern Africa: evidence from seismic S and P receiver functions.Geophysical Journal International, Vol. 179, 1, pp. 279-298.Africa, South AfricaGeophysics - seismics
DS201809-2051
2018
Vinnik, L.Kraft, H.A., Vinnik, L., Thybo, H.Mantle transition zone beneath central eastern Greenland: possible evidence for a deep tectonosphere from receiver functions.Tectonophysics, Vol. 728, 1, pp. 34-40.Europe, Greenlandgeophysics - seismic

Abstract: We investigate the mantle of central-eastern Greenland by using recordings with data from 24 local broad-band seismograph stations. We apply P wave receiver function technique and evaluate the difference in the arrival times of seismic phases that are formed by P to SV mode conversion at the 410-km and 660-km seismic discontinuities. These boundaries mark the top and bottom of the mantle transition zone (MTZ). The difference in the arrival time of the phases from the 410-km and 660-km discontinuities is sensitive to the thickness of the MTZ and relatively insensitive to volumetric velocity anomalies above the 410-km discontinuity. Near the east coast of Greenland in the region of the Skaergaard basalt intrusions we find two regions where the differential time is reduced by more than 2 s. The 410-km discontinuity in these regions is depressed by more than 20 km. The depression may be explained by a temperature elevation of 150 °C. We hypothesize that the basaltic intrusions and the temperature anomalies at a depth of 400 km are, at least partly, effects of the passage of Greenland over the Iceland hotspot at about 55 Ma. This explanation is consistent with the concept of tectosphere and implies that the upper mantle to a depth of 400 km translates coherently with the Greenland plate.
DS201811-2584
2018
Vinnik, L.Kosarev, G., Oreshin, S., Vinnik, L., Makeyeva, L.Mantle transition zone beneath the central Tien Shan: lithospheric delamination and mantle plumes.Tectonophysics, Vol. 723, 1, pp. 172-177.Chinaplumes

Abstract: We investigate structure of the mantle transition zone (MTZ) under the central Tien Shan in central Asia by using recordings of seismograph stations in Kyrgyzstan, Kazakhstan and adjacent northern China. We apply P-wave receiver functions techniques and evaluate the differential time between the arrivals of seismic phases that are formed by P to SV mode conversion at the 410-km and 660-km seismic boundaries. The differential time is sensitive to the thickness of the MTZ and insensitive to volumetric velocity anomalies above the 410-km boundary. Under part of the southern central Tien Shan with the lowest S wave velocity in the uppermost mantle and the largest thickness of the crust, the thickness of the MTZ increases by 15-20 km relative to the ambient mantle and the reference model IASP91. The increased thickness is a likely effect of low (about ? 150 K) temperature. This anomaly is indicative of delamination and sinking of the mantle lithosphere. The low temperature in the MTZ might also be a relic of subduction of the oceanic lithosphere in the Paleozoic, but this scenario requires strong coupling and coherence between structures in the MTZ and in the lithosphere during plate motions in the last 300 Myr. Our data reveal a reduction of thickness of the MTZ of 10-15 km under the Fergana basin, in the neighborhood of the region of small-scale basaltic volcanism at the time near the Cretaceous-Paleogene boundary. The reduced thickness of the MTZ is the effect of a depressed 410-km discontinuity, similar to that found in many hotspots. This depression suggests a positive temperature anomaly of about 100-150 K, consistent with the presence of a thermal mantle plume. A similar depression on the 410-km discontinuity is found underneath the Tarim basin.
DS1992-0984
1992
Vinnik, L.P.Makeyeva, L.I., Vinnik, L.P., Roecker, S.W.Shear-wave splitting and small scale convection in the continental uppermantleNature, Vol. 358, No. 6382, July 9, pp. 144-146MantleGeodynamics, Geophysics -convection
DS1992-1608
1992
Vinnik, L.P.Vinnik, L.P., Farra, V.Multiple Ses technique for measuring anistropy in the mantleGeophysical Research Letters, Vol. 19, No. 5, March 3, pp. 489-492MantleAnistropy, Geophysics -seismics
DS1993-1673
1993
Vinnik, L.P.Vinnik, L.P., Usenko, A.Yu., akeyeva, L.I., Oreshin, S.I.Strain state of the upper mantle under the USSRDoklady Academy of Sciences USSR, Earth Science Section, Vol. 318, No. 1-6, March 1992 Publishing date pp. 56-61.RussiaMantle, Geophysics
DS1995-1999
1995
Vinnik, L.P.Vinnik, L.P., Green, R.W.E., Nicolaysen, L.O., KosarevDeep seismic structure and kimberlites of the Kaapvaal cratonProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 656.South AfricaGeophysics -seismics, Craton -Kaapvaal
DS1996-0388
1996
Vinnik, L.P.Dricker, I.G., Roecker, S.W., Kosarev, G.L., Vinnik, L.P.Shear wave velocity structure of the crust and upper mantle beneath the Kola Peninsula.Geophysical Research. Letters, Vol. 23, No. 23, Nov. 15, pp. 3389-3392.Russia, Kola PeninsulaGeophysics - seismics, Mantle
DS1996-1482
1996
Vinnik, L.P.Vinnik, L.P., Green, R.W.E., Nicolaysen, L.O.Seismic constraints on dynamics of the mantle of the Kaapvaal cratonPhysics of the Earth and Planetary Interiors, Vol. 95, pp. 139-151.South AfricaGeophysics -seismics, Kaapvaal Craton
DS1996-1483
1996
Vinnik, L.P.Vinnik, L.P., Green, R.W.E., Nicolaysen, L.O., Kosarev...Deep seismic structure of the Kaapvaal CratonTectonophysics, Vol. 262, No. 1-4, Sept. 30, pp. 67-75.South Africa, southern AfricaGeophysics - seismics, Craton - Kaapvaal
DS200412-1479
2004
Vinnik, L.P.Oreshin, S.I., Vinnik, L.P.Heterogeneity and anisotropy of seismic attenuation in the inner core.Geophysical Research Letters, Vol. 31, 2, 10.1029/2003 GLO18591MantleGeophysics - seismics
DS200612-0356
2005
Vinnik, L.P.Du, Z., Vinnik, L.P., Foulger, G.R.Evidence from P to S mantle converted waves for a flat '660 km' discontinuity beneath Iceland.Earth and Planetary Science Letters, Vol. 241, 1-2, pp. 271-280.Europe, IcelandPlume, boundary, hot spot
DS201112-0762
2011
Vinnik, L.P.Oreshin, S.I., Vinnik, L.P., Kiselev, S.G., Rai, S.S., Prakasam, K.S., Treussov, A.V.Deep seismic structure of the Indian shield, western Himalaya, Ladakh, and Tibet.Earth and Planetary Science Letters, Vol. 307, 3-4, pp. 415-429.IndiaSubduction
DS201112-0899
2011
Vinograd, V.L.Safonov, O.G., Bindi, L., Vinograd, V.L.Potassium bearing clinopyroxene: a review of experimental, crystal chemical and thermodynamic dat a with petrological applications.Mineralogical Magazine, Vol. 75, 4, August pp. 2467-2484.TechnologyUpper mantle conditions
DS201112-1144
2011
Vinograd, V.L.Yu, Y.G., Wentzcovitch, R.M., Vinograd, V.L., Angel, R.J.Thermodynamic properties of MgSiO3 majorite and phase transitions near 660 km depth in MgSiO3 and Mg2SiO4: a first principles study.Journal of Geophysical Research, Vol. 116, B02208 ( 19p)MantleThermodynamics
DS1960-0759
1966
Vinogradov, A.P.Vinogradov, A.P., Kropotova, O.I., Orlov, Y.U., Grinenko, V.A.Isotopic Composition of Diamond Crystals and CarbonadoTranslation From Institute Geochemistry And Analytical Chemistry, 3P.Russia, BrazilIsotope
DS1987-0589
1987
Vinogradov, V.I.Pokrovskiy, B.G., Vinogradov, V.I.Isotope composition of some elements in ultrabasic Alkaline rocks of the Meimecha-Kotui province.(USSR).(Russian)Soviet Geology, (Russian), No. 5, pp. 81-91RussiaBlank
DS1991-1363
1991
Vinogradov, V.I.Pokrovskiy, B.G., Vinogradov, V.I.Isotope investigations on alkalic rocks of central and western SiberiaInternational Geology Review, Vol. 33, No. 2, February pp. 122-134RussiaGeochronology, Alkaline rocks
DS1996-1484
1996
Vinogradov, V.I.Vinogradov, V.I., Pichugin, L.P., Buyakaite, M.I.Isotopic features and dating of epigenetic alterations of upper Precambrian deposits of the Ural UpliftLithology and Mineral resources, Vol. 31, No. 1, Jan. pp. 60-69Russia, UralsAlteration, Geochronology
DS202112-1946
2022
Vinogradova, Y.C.Shatskiy, A., Bekhtenova, A., Arefiev, A.V., Podborodnikov, I.V., Vinogradova, Y.C., Rezvukin, D.I., Litasov, K.D.Solidus and melting of carbonated phlogopite peridotite at 3-6.5 Gpa: implications for mantle metasomatism.Gondwana Research, Vol. 101, 156-174. pdfRussiadeposit - Udachnaya

Abstract: It is well known that water significantly lowers mantle solidi. But it turns out this paradigm is not always true. Here, we studied the interaction of K-rich carbonate melts with the natural garnet lherzolite from the Udachnaya kimberlite (Russia) in the presence of water at 3.0-6.5 GPa, corresponding to depths of 100-200 km. We found that at ? 1100 °C, the metasomatic interaction consumes garnet, orthopyroxene, and melt to produce phlogopite ± K-richterite + magnesite ± dolomite. Besides, primary clinopyroxene is replaced by one with a lower amount of jadeite component. Thus, the addition of water to the K-rich carbonate melt, infiltrating the subcontinental lithospheric mantle, should yield its partial or complete disappearance accompanied by phlogopitization and carbonation. The studied systems have H2O/K2O = 2, like that in phlogopite, and therefore correspond to carbonated phlogopite peridotite under fluid-absent conditions. At 4.0-6.5 GPa, the solidus of carbonated phlogopite peridotite is controlled by the following reaction: phlogopite + clinopyroxene + magnesite = garnet + orthopyroxene + olivine + hydrous K-carbonatite melt, which is bracketed between 1100 and 1200 °C. At 3 GPa, the solidus temperature decreases to about 1050 °C presumably owing to the Ca-Mg exchange reaction, clinopyroxene + magnesite = orthopyroxene + dolomite, which stabilizes dolomite reacting with phlogopite at a lower temperature than magnesite. Our results suggest that the phlogopite- and carbonate-rich metasomatic vein networks, weakening rigid lithosphere and promoting continental rifting, could be formed as a result of infiltration of hydrous K-carbonatite melt at the base of subcontinental lithospheric mantle. Stretching and thinning of the cratonic lithosphere make geotherms warmer and shifts their intersections with the solidus of carbonated phlogopite peridotite to shallower depths. Consequently, the successive erosion of the continental lithosphere and ascent of the lithosphere-asthenosphere boundary during continental rifting should be accompanied by remelting of phlogopite-carbonate metasomes, upward percolation of K-rich melt, and its solidification at the front of the magmatic-metasomatic mantle system.
DS202105-0789
2021
Vinogradova, Y.G.Shatskiy, A., Podborodnikov, I.V., Arefiev, A.V., Bekhtenova, A., Vinogradova, Y.G., Stepanov, K.M., Litasov, K.D.Pyroxene-carbonate reactions in the CaMgSi206+-NaAlSi206+MgC03+-Na2C03+-K2C03 system at 3-6 Gpa: implications for partial melting of carbonated peridotite.Contributions to Mineralogy and Petrology, Vol. 176, 34 21p. PdfMantlecarbonatites

Abstract: The reactions between pyroxenes and carbonates have been studied in the CaMgSi2O6 + MgCO3 (Di + 2Mgs), CaMgSi2O6 + NaAlSi2O6 + 2MgCO3 (Di + Jd + 2Mgs), CaMgSi2O6 + Na2Mg(CO3)2 (Di + Eit), and CaMgSi2O6 + K2Mg(CO3)2 (Di + K2Mg) systems at pressures of 3.0 and 4.5 GPa in the temperature range 850-1300 °C and compared with those established previously at 6.0 GPa. The Di + 2Mgs solidus locates at 1220 °C / 3 GPa and 1400 °C / 6 GPa. Near-solidus melt is carbonatitic with SiO2 < 4 wt% and Ca# 56. The Di + Jd + 2Mgs solidus locates near 1050 °C at 3 GPa, rises to 1200 °C at 4.5 GPa, and 1350 °C at 6 GPa. The solidus is controlled by the reaction: 4NaAlSi2O6.2CaMgSi2O6 (clinopyroxene) + 12MgCO3 (magnesite) = 2MgAl2SiO6.5Mg2Si2O6 (clinopyroxene) + 2[Na2CO3.CaCO3.MgCO3] (liquid) + 6CO2. As pressure increases, the composition of solidus melt evolves from 26Na2CO3?74Ca0.58Mg0.42CO3 at 3 GPa to 10Na2CO3?90Ca0.50Mg0.50CO3 at 6 GPa. Melting in the Di + Eit and Di + K2Mg systems is controlled by the reactions: CaMgSi2O6 (clinopyroxene) + 2(Na or K)2 Mg(CO3)2 (eitelite) = Mg2Si2O6 (orthopyroxene) + 2[(Na or K)2CO3?Ca0.5Mg0.5CO3] (liquid). The Di + Eit solidus locates at 925 °C / 3 GPa and 1100 °C / 6 GPa, whereas the Di + K2Mg solidus is located at 50 °C lower. The resulting melts have alkali-rich carbonate compositions, (Na or K)2CO3?Ca0.4Mg0.6CO3. The obtained results suggest that most carbonates belong to the ultramafic suite would survive during subduction into the deep mantle and experience partial melting involving alkaline carbonates, eitelite or K2Mg(CO3)2, under geothermal conditions of the subcontinental lithospheric mantle (35-40 mW/m2). On the other hand, the jadeite component in clinopyroxene would be an important fluxing agent responsible for the partial melting of carbonated rocks under the rift margin geotherm (60 mW/m2) at a depth of about 100 km, yielding the formation of Na-carbonatite melt.
DS202202-0214
2022
Vinogradova, Y.G.Shatskiy, A., Bekhtenova, A., Podborodnikov, I.V., Arefiev, A.V., Vinogradova, Y.G., Litasov, K.D.Solidus of carbonated phlogopite eclogite at 3- 6 Gpa: implications for mantle metasomatism and ultra high pressure metamorphism.Gondwana Research, Vol. 103, pp. 108-204. pdfMantlemetasomatism

Abstract: The interaction of natural eclogite (Ecl) with synthetic hydrous carbonate melts with Na:K = 0:1 (KH2) and 1:1 (NKH2) was studied in multianvil experiments at 3-6 GPa and 850-1250 °C. The interaction with KH2 consumes garnet and clinopyroxene producing phlogopite and calcite-dolomite solid solution. Besides, the interaction yields a decrease in the jadeite component of clinopyroxene, evolving eclogite toward pyroxenite. This is consistent with a metasomatic alteration of eclogite xenoliths, manifested as Na-poor “spongy” clinopyroxene, replacing primary omphacite, and kelyphitic rims around garnet, containing phlogopite and carbonates. The interaction with NKH2 also produces phlogopite and carbonate, but the latter is more magnesian and represented by magnesite, above the solidus, and magnesite + dolomite below the solidus. The interaction with NKH2 increases the jadeite component in clinopyroxene and grossular component in garnet, evolving eclogite Group A to eclogite Group B. The studied systems have H2O/K2O = 2, like that in phlogopite, and therefore correspond to carbonated phlogopite eclogite under fluid-absent conditions. Based on the obtained results its solidus is situated near 1050 °C at 3 GPa and decreases to 950 °C at 6 GPa. Thus, hydrous K- and Na-K-carbonatite melts can coexist with eclogite in SCLM at depths exceeding 120-170 km, and solidify as temperature decreases below 950-1050 °C according to the following solidus reactions: pyrope + diopside + melt ? phlogopite + dolomite, below 6 GPa, and pyrope + diopside + melt ? phlogopite + magnesite + grossular, at 6 GPa. The melting reaction, involving phlogopite and dolomite, suggests the partial melting at the peak of ultrahigh-pressure metamorphism (UHPM) during continent-continent plate collision. The prograde P-T path of UHPM crosses the solidus of clinopyroxene + garnet + phlogopite + dolomite assemblage at 4.7-5.2 GPa and 970-990 °C and yields the formation of hydrous K-carbonatite melt-fluid in situ. This melt could be responsible for the formation of K-bearing clinopyroxenes and microdiamonds in the UHPM marbles in the Kokchetav massif, Kazakhstan. The retrograde P-T path intersects the solidus that has a negative Clapeyron slope in the diamond stability field. Thus, the hydrous K-carbonatite melt should disappear soon after the peak of metamorphism reacting with garnet to produce Ca-Mg carbonates and phlogopite.
DS1998-1467
1998
VinokovTitkov, S., Gorshkov, Vinokov, Bershov, Solodov, SivtsovCarbonado from Yakutian diamond deposits (Russia): microinclusions, impurities and paragenetic centres.7th International Kimberlite Conference Abstract, pp. 914-6.Russia, YakutiaCarbonado, Deposit - Udachnaya
DS2001-1160
2001
VinokurovTitkov, S.V., Gorshkov, Vinokurov, Bershov, SolodovGeochemistry and genesis of carbonado from Yakutian diamond depositsGeochemistry International, Vol. 39, No. 3, pp. 228-36.Russia, YakutiaMicroinclusions, Carbonado
DS2002-0598
2002
VinokurovGorshkov, A.I., Titkov, Vinokurov, Ryabchikov, BaoStudy of cubic diamond crystal from a placer in northern Chin a by analytical electron microscopy...Geochemistry International, Vol.40,3,pp.299-305., Vol.40,3,pp.299-305.ChinaDiamond - morphology, neutron activation analysis, Alluvials
DS2002-0599
2002
VinokurovGorshkov, A.I., Titkov, Vinokurov, Ryabchikov, BaoStudy of cubic diamond crystal from a placer in northern Chin a by analytical electron microscopy...Geochemistry International, Vol.40,3,pp.299-305., Vol.40,3,pp.299-305.ChinaDiamond - morphology, neutron activation analysis, Alluvials
DS1998-0524
1998
Vinokurov, S.F.Gorshkov, A.I., Vinokurov, S.F., et al.Polycrystalline diamond from the Udachnaya pipe: mineralogical, geochemical and genetic charcteristics.Lithology and MIneral Resources, Vol. 33, No. 6, Nov-Dec. pp. 525-538.Russia, YakutiaMineralogy, geochemistry, Deposit - Udachanaya
DS1998-1547
1998
Vinokurov, S.F.Vinokurov, S.F., Gorshkov, A.I., Lapina, M.I.Diamonds from kimberlite Diatreme 50, Liaoning Province, China:microtextural, mineralogical, geneticGeochemistry International, Vol. 36, No. 8, Aug. 1, pp. 676-683.ChinaTextures, petrology, Deposit - Diatreme 50
DS200412-0697
2004
Vinokurov, S.F.Gorshkov, A.I., Bershov, I.V., Titkov, S.V., Vinokurov, S.F.Mineral inclusions and impurities in diamonds from lamproites of the Argyle pipe, West Australia.Geochemistry International, Vol. 41, 12, pp. 1143-1151.AustraliaDeposit - Argyle, mineralogy
DS2002-0600
2002
VinolurovGorshkov, A.I., Titkov, Vinolurov, Ryabchikov, BaoStudy of a cubic diamond crystal from a placer by analytical electron microscopy neuton activation anal.Gochemistry International, Vol.40, 3, pp.299-305.China, northernAlluvials - diamond morphology
DS200712-1003
2006
Vins, V.Smirnov, S., Ananyev, S., Kalinia, V., Vins, V.Color grading of color enhanced natural diamonds: a case study of Imperial red diamonds.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.126-7. abstract onlyTechnologyColour grading
DS201112-1092
2011
Vins, V.Vins, V.Donor nitrogen aggregation in diamonds annealed in the graphite stability field.GIA International Symposium 2011, Gems & Gemology, Summer abstract p. 106.TechnologyDiamond morphology
DS202201-0011
2021
Vins, V.Deljanin, B., Collins, A., Zaitsev, A.,Lu, T., Vins, V., Chapman, J., Hainschwang, T.Diamonds - natural, treated & laboratory grown.Gemmological Research Industries Inc. Vancouver B.C., isbn 978-1777369231 184p.GlobalBook - notice

Abstract: For those who have some portable and advanced instruments, this book will serve as a handbook with many useful spectra, cross polarised filters and fluorescence reactions to compare, plus an Appendix with results of tests conducted using 11 portable instruments on 64 samples, and suggestions as to what instruments to use depending on budget and needs. Even if you are not a diamond specialist but are merely interested in the science of diamond, or you trade in diamonds, the information in this book will make you more knowledgeable and confident to talk about this beautiful gem with friends and clients.
DS1988-0735
1988
Vins, V.G.Vins, V.G., Eliseev, A.P., et al.Optical spectroscopy of neutron irradiated synthetic diamonds.(Russian)Sverkhtverd. Mater. (Russian), No. 4, pp. 18-22GlobalLuminesence, Spectrometry
DS200712-1124
2006
Vins, V.G.Vins, V.G., Yeliseyev, A., Chilgrin, S.V., Grizenko, A.G.Natural diamond enhancement: the transformation of intrinsic and impurity defects in the diamond lattice.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.120, abstract onlyTechnologyDiamond morphology
DS201412-0196
2013
Vins, V.G.Dobrinets, I.A., Vins, V.G., Zaitsev, A.M.HPHT-treated diamonds: diamonds forever.Springer, 257p. Approx $ 140.TechnologyBook
DS201212-0195
2012
Vinson, J.Farges, F., Vinson, J., Rehr, J.R., Post, J.E.Spectroscopy of B doped diamonds: experiment vs. theory. Hope, Tavernier Blue, French Blueemc2012 @ uni-frankfurt.de, 1p. AbstractTechnologyDiamond - colour
DS1998-0353
1998
Vinyu, M.Dirks, P.H.G.M., Jelsma, H.A., Vinyu, M., MunyanyiwaThe structural history of the Zambesi Belt in northeast Zimbabwe: evidence for crustal extension - Pan AfricanSouth African Journal of Geology, Vol. 101, No. 1, March pp. 1-16ZimbabweStructure, Orogeny - Pan-African
DS1993-0744
1993
Vinyu, M.L.Jelsma, H.A., Van der Beek, P.A., Vinyu, M.L.Tectonic evolution of the Bindura-Shamva greenstone belt (northernZimbabwe): progressive deformation around diapiric batholithsJournal of Structural Geology, Vol. 15, No. 2, pp. 165-176ZimbabweStructure, Greenstone belt
DS1996-0683
1996
Vinyu, M.L.Jelsma, H.A., Vinyu, M.L., Verdurmen, E.A.T.Constraints on Archean crustal evolution of the Zimbabwe craton: a uranium-lead (U-Pb) (U-Pb)zircon, samarium-neodymium (Sm-Nd),lead-lead studyChemical Geology, Vol. 129, No. 3/4, July 29, pp. 55-81Zimbabwe, South AfricaGeochronology, Craton
DS2001-1203
2001
Vinyu, M.L.Vinyu, M.L., Hanson, R.E., Martin, M.W., Bowringuranium-lead (U-Pb) zircon ages from craton margin Archean orogenic belt in northern Zimbabwe.Journal of African Earth Sciences, Vol. 32, No. 1, Jan. pp. 103-114.ZimbabweCraton, Geochronology
DS2002-0116
2002
Viola, G.Basson, I.J., Jelsma, H., Viola, G.Rapid kimberlitic fluid extraction from mantle lithosphere11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 20.AfricaMelting - LPO orientation
DS2002-0117
2002
Viola, G.Basson, I.J., Viola, G.Kimberlite dykes: active or passive magma emplacement?11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 20.MantleMagma - dikes
DS2003-0081
2003
Viola, G.Basson, I.B., Viola, G.Passive kimberlitic fluid emplacement into dilating dyke fracture systems in South8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractSouth AfricaBlank
DS2003-0082
2003
Viola, G.Basson, I.J., Viola, G.Structural overview of selected Group II kimberlite dyke arrays in South Africa:South Africa Journal of Geology, South AfricaBlank
DS200412-0109
2003
Viola, G.Basson, I.B., Viola, G.Passive kimberlitic fluid emplacement into dilating dyke fracture systems in South Africa.8 IKC Program, Session 8, POSTER abstractAfrica, South AfricaDiamond exploration
DS200412-0110
2003
Viola, G.Basson, I.J., Viola, G.Structural overview of selected Group II kimberlite dyke arrays in South Africa: implication for kimberlite emplacement merchaniSouth African Journal of Geology, Vol. 106, 4, pp. 375-394.Africa, South Africa, LesothoGeodynamics, genesis, Klipspringer, Helam, Star
DS200412-0911
2004
Viola, G.Jelsma, H.A., De Wit, M.J., Thiart, C., Dirks, P.H.G.M., Viola, G., Basson, U., Anckar, E.Preferential distribution along transcontinental corridors of kimberlites and related rocks of Southern Africa.South African Journal of Geology, Vol. 107, 1/2, pp. 302-324.Africa, South AfricaTectonics, structures, lineaments
DS200612-0137
2006
Viola, G.Bird, P., Ben Avraham, Z., Schubert, G., Andreoli, M., Viola, G.Patterns of stress and strain rate in southern Africa.Journal of Geophysical Research, Vol. 111, B8, August 11, B08402.Africa, South Africa, BotswanaGeophysics
DS200612-0138
2006
Viola, G.Bird, P., Ben Avraham, Z., Schubert, G., Andreoli, M., Viola, G.Patterns of stress and strain rate in southern Africa.Journal of Geophysical Research, Vol. 111, B8, B0802.Africa, South AfricaGeophysics - seismics
DS200812-1213
2008
Viola, G.Viola, G., Henderson, I.H.C., Bingen, B., Thomas, R.J., Smethurst, M.A., De Azavedo, S.Growth and collapse of a deeply eroded orogen: insights from structural, geophysical, and geochronological constraints on Pan-African evolution of NE Mozambique.Tectonics, Vol. 27, TC5009Africa, MozambiqueGeochronology
DS1990-0116
1990
Virag, A.Amari, S., Anders, E., Virag, A.Interstellar graphite in meteoritesNature, Vol. 345, No. 6272, May 17, p. 238-239GlobalMeteorites, Graphite
DS1993-0271
1993
Viramonte, J.Coira, B., Malhburg, Kay, S., Viramonte, J.Upper Cenozoic magmatic evolution of the Argentine Puma - a model for changing subduction geometryInternational Geology Review, Vol. 35, No. 8, August pp. 677-720Peru, Bolivia, CHileAltiplano, Tectonics
DS1987-0545
1987
Viramonte, J.G.Omarin, R.H., Salfity, J.A., Linares, E., Viramonte, J.G.Petrology, geochemistry and age of a lamproite dike In the PirguaSubgroup, Alemania, Salta. SPA.Revista del Instituto de Geologia y Mineria, *SPA., No. 7, pp. 89-99GlobalLamproite, Geochemistry
DS201912-2822
2019
Virgl, J.Shapka, C., Virgl, J., Mclean, S.Dust in the wind: vegetation, soils and dust deposition monitoring at the Gahcho Kue mine.Yellowknife Forum NWTgeoscience.ca, abstract volume p. 85.Canada, Northwest Territoriesdeposit - Gahcho Kue

Abstract: A vegetation and soils monitoring program was implemented at the Gahcho Kué Mine to test for mine-related changes to vegetation and soils from dust deposition. Besides measuring changes in vegetation and soils, one objective of the study is to inform the Wildlife Effects Monitoring Program with respect to the potential for dust as a mechanism for avoidance of habitats near the Mine by caribou and other wildlife. Soil properties, plant communities, and dust deposition have been monitored since 2013 with permanent vegetation plots and dust collectors using a gradient study design prior to and during construction and operation of the Mine. A single study area transect was established in a west-southwest direction extending 20 kilometres from the Mine footprint, which was based on the prevailing wind direction and terrain features (i.e., large lakes), and the distribution of the target plant community across the landscape. Dustfall deposition and associated metals concentrations, and soil moisture and temperature variables are monitored annually. Data on plant species richness and abundance and soil pH and salinity are collected every three years. Analysis of variance was performed to determine if fixed dustfall deposition rates varied among sampling areas, seasons, and years. A repeated measures analysis of variance was used to examine patterns of species abundance (percent cover) and species richness across sampling areas and years. Although dust deposition has shown increasing trends since the commencement of construction and operation, no effects on vegetation from dust were observed in the current analysis. Metals concentrations in dust were generally below detection limits or in trace amounts, consistent with baseline values, and soil pH and salinity were within baseline values. Minor observed changes in species richness are likely related to natural variation in site conditions among vegetation plots and associated sampling areas, annual variation in climate, surveyor variability, and foraging by caribou and other wildlife. Differences in annual dust deposition rates may be attributed to annual variations in temperature, wind, and rainfall. The results suggest that dust-related changes in vegetation community composition is likely not a factor influencing the avoidance of habitats near the Mine by caribou or other wildlife.
DS200612-1324
2005
Virgl, J.A.Smith, A.C., Virgl, J.A., Panayi, D., Armstrong, A.R.Effects of a diamond mine on Tundra breeding birds.Arctic ( Arctic Institute of North America), Vol. 38, 3, pp. 295-304.Canada, Northwest TerritoriesEnvironemental
DS201112-0216
2011
Virgl, J.A.Coulton, D.W., Virgl, J.A., English, C.Raptor occupancy and productivity near a barren-ground diamond mine, Northwest Territories.Yellowknife Geoscience Forum Abstracts for 2011, abstract p. 30.Canada, Northwest TerritoriesDiavik mine
DS1987-0764
1987
Virgo, D.Virgo, D., Luth, R.W., Moats, M.A., Ulmer, G.C.The redox state of the mantle: evidence from mantle derived ilmenitesGeological Society of America, Vol. 19, No. 7 annual meeting abstracts, p.877. abstracGlobalilmenites
DS1987-0804
1987
Virgo, D.Wood, B.J., Virgo, D.Oxidation state of the Upper mantle: ferric-ferrous ratios incoexisting minerals from spinel lherzolitesGeological Society of America, Vol. 19, No. 7 annual meeting abstracts, p.896. abstracNew MexicoKilbourne Hole
DS1988-0106
1988
Virgo, D.Canil, D., Virgo, D., Scarfe, C.M.Oxidation state of spinel lherzolite xenoliths from British Columbia: a57Fe Mossbauer investigationCarnegie Institute Annual Report of the Director of the Geophysical, No. 2102, issued Dec. 1988, pp. 18-22British ColumbiaSummit Lake, Rayfield River, West Kettle River
DS1988-0427
1988
Virgo, D.Luth, R.W., Virgo, D., Boyd, F.R., Woodm B.J.Iron in mantle derived garnets: valence and structural stateCarnegie Institute Annual Report of the Director of the Geophysical, No. 2102, issued Dec. 1988, pp. 13-18South AfricaExperimental description
DS1990-0270
1990
Virgo, D.Canil, D., Virgo, D., Scarfe, C.M.Oxidation state of mantle xenoliths from British Columbia, CanadaContributions to Mineralogy and Petrology, Vol. 104, pp. 453-462British ColumbiaMantle xenoliths Boss Mountain, Rayfield River, Kostal Lake, West Kettle
DS1990-0960
1990
Virgo, D.Luth, R.W., Virgo, D., Boyd, F.R., Wood, B.J.Ferric iron in mantle derived garnetsContributions to Mineralogy and Petrology, Vol. 104, pp. 56-72GlobalMantle, Garnet analyses
DS2000-0982
2000
Virgo, D.Virgo, D., Popp, R.K.Hydrogen deficiency in mantle derived phlogopitesAmerican Mineralogist, Vol. 85, pp. 753-9.NamibiaOkenyenya Igneous Complex - lamprophyre dyke, Kaersutite
DS1983-0618
1983
Virovlyanskiy, G.M.Virovlyanskiy, G.M., Zhirova, L.T.Change in rock types with depth in plutons of the Meymecha -Kotuyul tramafic alkalic complexDoklady Academy of Science USSR, Earth Science Section, Vol. 273, December pp. 39-43RussiaAlkaline Rocks
DS1999-0378
1999
Virransalo, P.Korsman, K., Toivo, K., Virransalo, P.The GGT SVEKA Transect: structure and evolution of the continental crust In the Paleoproterozoic SvecofennianInternational Geology Review, Vol. 41, No. 4, Apr. pp. 287-333.FinlandGeophysics - seismics, Geodynamics
DS201312-0892
2013
Viryus, A.A.Suk, N.I., Kotelnikov, A.R., Viryus, A.A.Crystallization of loparite in alkaline fluid magmatic systems ( from experimental and mineralogical data).Russian Geology and Geophysics, Vol. 54, 4, pp. 436-453.TechnologyAlkalic
DS2000-0391
2000
Vis, R.D.Harris, P.J.F., Vis, R.D., Heymann, D.Fullerene like carbon nanostructures in the Allende meteoriteEarth and Planetary Science Letters, Vol.183, No.3-4, pp.355-59.GlobalMeteorite, Fullerene
DS2003-0218
2003
Viscona, D.Carraro, A., Viscona, D.Mantle xenoliths in Triassic camptonite dykes of the Predazzo area ( dolomitesEuropean Journal of Mineralogy, Vol. 15, 1, pp. 103-116.ItalyCamptonite
DS200712-0244
2007
Vishnev, V.S.Diakonova, A.G., Ivanov, K.S., Astafiev, P.F., Vishnev, V.S., Konoplin, A.D.Resistivity pattern of crust and upper mantle in Southern Urals.Russian Geology and Geophysics, Vol. 48, pp. 844-850.Russia, UralsGeophysics - EM, tectonics
DS200912-0193
2009
Vishnev, V.S.Dyakonova, A.G., Ivanov, K.S., Surina, O.V., Asafev, P.F., Vishnev, V.S., Konoplin, A.D.The structure of the tectonosphere of the Urals and West Siberian platform by electromagnetic data.Doklady Earth Sciences, Vol. 423, 3-6, pp. 1479-1481.RussiaGeophysics - EM
DS200912-0194
2008
Vishnev, V.S.Dyakonova, A.G., Ivanov, K.S., Surina, O.V., Astafev, P.F., Vishnev, V.S., Konoplin, A.D.The structure of the tectonosphere of the Urals and West Siberian Platform by electromagnetic data.Doklady Earth Sciences, Vol. 423A, No. 9, pp. 14791482.Russia, SiberiaGeophysics
DS2003-1101
2003
Vishnevky, S.Pratesi, G., Lo Giudice, A., Vishnevky, S., Manfredotti, C., Cipriani, C.Cathodluminescence investigations on the Popigai Ries and Lappajarvi impactAmerican Mineralogist, Vol. 88, pp. 1778-87.Russia, Siberia, FinlandMeteorite
DS200412-1577
2003
Vishnevky, S.Pratesi, G., Lo Giudice, A., Vishnevky, S., Manfredotti, C., Cipriani, C.Cathodluminescence investigations on the Popigai Ries and Lappajarvi impact diamonds.American Mineralogist, Vol. 88, pp. 1778-87.Russia, Siberia, Baltic ShieldMeteorite
DS1991-0068
1991
Vishnevskaya, A.A.Bao, J.N., Matsyuk, S.S., Vishnevskaya, A.A.Garnets from Chin a kimberlites (technical note).(Russian)Izvest. Akad. Nauk SSSR, (Russian), No. 8, August pp. 152-157ChinaPetrology, Garnets
DS1987-0446
1987
Vishnevskii, A.A.Matsyuk, S.S., Vishnevskii, A.A., Platonov, A.N., Kharkiv, A.D.Composition and optical spectroscopic characteristics of garnets from peridotites-pyroxenite intrusives of the Czech Massif.(Russian)Mineral. Zhurn., (Russian), Vol. 9, No. 3, pp. 15-28GlobalBlank
DS1988-0349
1988
Vishnevskii, A.A.Kharkiv, A.D., Bogatykh, M.M., Vishnevskii, A.A.Mineral composition of kelphyitic rims developed on garnets fromkimberlites.(Russian)Zap. Vses. Mineral. O-Va, (Russian), Vol. 117, No. 6, pp. 705-713RussiaGarnet analyses, Kelphyitic rims
DS1989-0770
1989
Vishnevskii, A.A.Kharkiv, A.D., Vishnevskii, A.A.Kelyphitization of garnet from xenoliths of deep seated rocks inkimberlites.(Russian)Zap. Vses. Mineral. O-Va, (Russian), Vol. 118, No. 4, pp. 27-37RussiaXenoliths, Garnet analyses
DS1992-1011
1992
Vishnevskii, A.A.Matsyuk, S.S., Vishnevskii, A.A., Cherenkova, A.F., Egorova, L.N.K-richterite bearing ilmenite clinohumite dunites: a new variety of Deep seated peridotites in kimberlites.Soviet Geology and Geophysics, Vol. 32, No. 12, pp. 64-70.Russia, SayanGeochemistry, mineral chemistry, Peridotite xenoliths
DS1986-0841
1986
Vishnevskii, S.A.Vishnevskii, S.A., Dolgov, Yu.A., Sobolev, N.V.Lamproites of the Talakhtakh diatreme on the eastern slope of the AnabarshieldSoviet Geology and Geophysics, Vol. 27, No. 8, pp. 15-24RussiaLamproite
DS1999-0773
1999
Vishnevskii, S.A.Vishnevskii, S.A., Palchik, N.A., Raitala, J.Diamonds in impactites of the Lappajarvi impact craterRussian Geology and Geophysics, Vol. 40, No. 10, pp. 1487-90.FinlandImpact crater
DS1983-0164
1983
Vishnevskiy, A.A.Buykov, V.I., Vishnevskiy, A.A., Tsymbal, S.N., Chebotarev, V.A.Optico-spectroscopic and Colorimetric Parameters of Pyrope And Pyrope-almandine of Sedimentary Deposits of Central Bug.Mineral. Zhurnal, Vol. 5, No. 3, PP. 42-49.RussiaPetrology, Kimberlite, Probe Data
DS1984-0750
1984
Vishnevskiy, A.A.Vishnevskiy, A.A., Kolesnik, YU.N., Kharkiv, A.D.Genesis of Kelphite Borders on Pyropes from KimberlitesMineral. Zhur., Vol. 6, No. 4, PP. 55-66.RussiaBlank
DS1987-0765
1987
Vishnevskiy, A.A.Vishnevskiy, A.A.Pecularities of the chemical composition of celphyitic reaction shells on garnets from kimberlite.(Russian)Mineral. Zhurnal, (Russian), Vol. 9, No. 2, April pp. 53-59RussiaMineral chemistry
DS1987-0766
1987
Vishnevskiy, A.A.Vishnevskiy, A.A.Chemical composition of kelphyitic reaction rims of garnets from kimberliterocks.(Russian)Mineral. Zhurn., (Russian), Vol. 9, No. 2, pp. 53-59RussiaBlank
DS1989-0771
1989
Vishnevskiy, A.A.Kharkiv, A.D., Vishnevskiy, A.A.Pyrope megacrystals with signs of partial melting; From kimberlite ofYakutia.(Russian)Mineral. Zhurnal., (Russian), Vol. 11, No. 5, pp. 28-36RussiaCrystallography, Pyrope
DS1990-1604
1990
Vishnevskiy, A.A.Yakovlev, B.G., Matsyuk, S.S., Vishnevskiy, A.A., Chubarov, V.M.Evolution of mineral equilibration temperatures and petrogenesis of the deep mafic ferruginous granulites from Yakutian kimberlite pipes.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 4, August pp. 3-15RussiaPetrology, Mineral chemistry
DS1994-0938
1994
Vishnevskiy, A.A.Kopylova, M.G., Vishnevskiy, A.A., Ilupin, L.P.High uvarovite garnet in the products of exsolution of chromium diopsideDoklady Academy of Sciences USSR, Vol. 326, pp. 108-112.RussiaMineralogy, Deposit -Obnazhennaya
DS1985-0702
1985
Vishnevskiy, A.S.Vishnevskiy, O.A., Kolesnik, Y.M., Vishnevskiy, A.S., Tkach, V.Pyrope with Crystalline Inclusions from Balta Deposits of The Central Bug Region, Dniester River Area.Dop. Akad. Nauk. Ukra. Ser. B., No. 4, PP. 9-14.Russia, UkraineKimberlite, Petrology, Inclusions
DS1985-0702
1985
Vishnevskiy, O.A.Vishnevskiy, O.A., Kolesnik, Y.M., Vishnevskiy, A.S., Tkach, V.Pyrope with Crystalline Inclusions from Balta Deposits of The Central Bug Region, Dniester River Area.Dop. Akad. Nauk. Ukra. Ser. B., No. 4, PP. 9-14.Russia, UkraineKimberlite, Petrology, Inclusions
DS1991-1806
1991
Vishnevsky, A.A.Vishnevsky, A.A.Kelyphites on garnets in mantle xenoliths and kimberlites: composition, genesis, petrological implicationsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 571-572RussiaMineral chemistry, Genesis
DS1950-0511
1959
Vishnevsky, N.A.Vishnevsky, N.A., Tabunov, S.M.The Mineralogy and Petrology of Nodules Found in the Kimberlites of the Southern Part of the Middle Olenek Region.Niiga., Vol. 107, PP. 5L-59.RussiaBlank
DS2002-1280
2002
Vishnevsky, S.Pratesi, G., Ciprani, C., Vishnevsky, S., Lo Giudice, A.FTIR spectroscopy study of impact diamonds18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.202.MantleImpact diamonds
DS1995-2000
1995
Vishnevsky, S.A.Vishnevsky, S.A., Afanasev, V.P., Koptil, V.I.Impact diamonds : their features, origin and significanceProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 657-659.GlobalDiamonds -impact, Meteorites
DS201908-1797
2019
Vishnevsky, S.A.Murri, M., Smith, R.L., McColl, K., Hart, M., Alvaro, M., Jones, A.P., Nemeth, P., Salzmann, C.G., Cora, F., Domeneghetti, M.C., Nestola, F., Sobolev, N.V., Vishnevsky, S.A., Logvinova, A.M., McMillan, P.F.Quantifying hexagonal stacking in diamond. ( lonsdaleite)Nature Scientific Reports, doi.org/10.1038/ s41598-019-46556-3 8p. PdfGlobaldiamond morphology, impact craters

Abstract: Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.
DS202011-2054
2020
Vishnevsky, S.A.Murri, M., Smith, R.L., McColl, K., Hart, M., Alvaro, M., Jones, A.P., Nemeth, P., Salzmann, C.G., Cora, F., Domeneghetti, M.C., Nestola, F., Sobolev, N.V., Vishnevsky, S.A., Logvinova, A.M., McMillan, P.F.Quantifying hexagonal stacking in diamond.Nature/scientific reports, 8p. PdfGlobalcrystallography

Abstract: Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.
DS201412-0919
2014
Vishnevskyy, A.A.Taran, M.N., Parisi, F., Lenaz, D., Vishnevskyy, A.A.Synthetic and natural chromium-bearing spinels: an optical spectroscopy study.Physics and Chemistry of Minerals, Vol. 41, 8, pp. 593-602.TechnologySpinel
DS200712-0032
2007
VishnyakovaAshchepkov, I.V., Pokhilenko, N.P., Logvinova, A.M., Vladykin, N.P., Rotman, Palessky, Alymova, VishnyakovaEvolution of kimberlite magmatic sources beneath Siberia.Plates, Plumes, and Paradigms, 1p. abstract p. A39.RussiaMir
DS200912-0016
2009
VishnyakovaAschepokov, L., Logvinova, A., Kuligin, Pokhilenko, Vladykin, Mityukhin, Alymova, Malygina, VishnyakovaClinopyroxene eclogite peridotite thermobarometry of the large Yakutian kimberlite pipes.Goldschmidt Conference 2009, p. A58 Abstract.Russia, YakutiaThermobarometry
DS201906-1346
2019
Vishwakarama, N.Shellnut, J.G., Hari, K.R., Liao, A.C.-Y., Denyszyn, S.W., Vishwakarama, N., Deshmukh, S.D.Petrogenesis of the 1.85 ga Sonakhan mafic dyke swrm, Bastar Craton.Lithos, Vol.334-335, pp. 88-101.Indiacraton

Abstract: The NNW trending tholeiitic Sonakhan mafic dyke swarm of the Northern Bastar Craton is comprised of basalt to basaltic andesite (SiO2?=?46.3?wt% to 55.3?wt%; Mg#?=?37 to 70) dykes. A single basaltic dyke yielded a weighted-mean 207Pb/206Pb baddeleyite age of 1851.1?±?2.6?Ma. The Sr and Nd isotopes (87Sr/86Sri?=?0.70396 to 0.70855; ?Nd(t)?=??5.7 to +2.0) are variable which is a consequence of crustal contamination. Trace element modeling suggests the dykes were likely derived by partial melting of a spinel-bearing mantle source. The Sonakhan dykes are 30 million years younger than the 1.88?Ga Bastar-Cuddapah dykes (Bastanar-Hampi swarm) of the southern and central Bastar Craton indicating they represent a distinct period of magmatism. However, much like the 1.88?Ga dykes, the Sonakhan dykes appear to be correlative with dykes from the Yilgarn Craton (Yalgoo dyke?=?1854?±?5?Ma) of Western Australia. The temporal and compositional similarity of the Sonakhan dykes with the Yalgoo dyke is evidence that they are petrologically related and may represent different branches of the same dyke swarm. The existence of two distinct Paleoproterozoic dyke swarms in the Bastar Craton that each have a correlative unit in the Yilgarn Craton is supportive of a link between India and Australia before 1.9?Ga. Moreover, it suggests that the break-up of India and Western Australia was protracted and lasted for at least 30 million years.
DS201903-0527
2019
Vishwakarma, N.Liao, A.C-Y., Shellnutt, J.G., Hari, K.R., Denyszyn, S.W., Vishwakarma, N., Verma, C.B.A petrogenetic relationship between 2.37 Ga boninitic dyke swarms of the Indian Shield: evidence from the Central Bastar Craton and NE Dharwar Craton.Gondwana Research, Vol. 69, pp. 193-211.Indiacraton

Abstract: The Indian Shield is cross-cut by a number of distinct Paleoproterozoic mafic dyke swarms. The density of dykes in the Dharwar and Bastar Cratons is amongst the highest on Earth. Globally, boninitic dyke swarms are rare compared to tholeiitic dyke swarms and yet they are common within the Southern Indian Shield. Geochronology and geochemistry are used to constrain the petrogenesis and relationship of the boninitic dykes (SiO2?=?51.5 to 55.7?wt%, MgO?=?5.8 to 18.7?wt%, and TiO2?=?0.30?wt% to 0.77?wt%) from the central Bastar Craton (Bhanupratappur) and the NE Dharwar Craton (Karimnagar). A single U-Pb baddeleyite age from a boninitic dyke near Bhanupratappur yielded a weighted-mean 207Pb/206Pb age of 2365.6?±?0.9?Ma that is within error of boninitic dykes from the Dharwar Craton near Karimnagar (2368.5?±?2.6?Ma) and farther south near Bangalore (2365.4?±?1.0?Ma to 2368.6?±?1.3?Ma). Rhyolite-MELTS modeling indicates that fractional crystallization is the likely cause of major element variability of the boninitic dykes from Bhanupratappur whereas trace element modeling indicates that the primary melt may be derived from a pyroxenite mantle source near the spinel-garnet transition zone. The Nd isotopes (?Nd(t)?=??6.4 to +4.5) of the Bhanupratappur dykes are more variable than the Karimnagar dykes (?Nd(t)?=??0.7 to +0.6) but they overlap. The variability of Sr-Nd isotopes may be related to crustal contamination during emplacement or is indicative of an isotopically heterogeneous mantle source. The chemical and temporal similarities of the Bhanupratappur dykes with the dykes of the Dharwar Craton (Karimnagar, Penukonda, Chennekottapalle) indicate they are members of the same giant radiating dyke swarm. Moreover, our results suggest that the Bastar and Dharwar Cratons were adjacent but likely had a different configuration at 2.37?Ga than the present day. It is possible that the 2.37Ga dyke swarm was related to a mantle plume that assisted in the break-up of an unknown or poorly constrained supercontinent.
DS200512-0586
2004
Vishwakarma, R.K.Kumar, C.S., Mukherjee, A., Vishwakarma, R.K.Discovery of a new kimberlite pipe using multidisciplinary approach at Kalyandurg, Anantapur District, Andhra Pradesh.Journal Geological Society of India, Vol. 64, 6, pp. 813-818.IndiaExploration - Kalyandurg
DS1988-0259
1988
Visnevskii, Ya.S.Golovko, A.V., Semeneev, R.R., Visnevskii, Ya.S.Characteristics and composition of camptonite dikes from the upper reaches of the Tamshush River in the Gissar Ridge (Uzbek SSSR).(Russian)Uzbekiston Geologiya Zhurnal., (Russian), No. 5, pp. 10-12RussiaCamptonite
DS1993-1674
1993
Visscher, G.T.Visscher, G.T., Nesting, D.C., et al.Polyphenylcarbene: a polymer precursor to diamond-like carbonScience, Vol. 260, No. 5113, June 4, pp. 1496-1499GlobalCarbon
DS1984-0751
1984
Visser, D.J.L.Visser, D.J.L.Geological Map of the Republics of South Africa, Transkei, Bophuthatswana, Venda and Ciskei and the Kingdoms of Lesotho and Swasiland.South Africa Geological Survey, 4 SHEETS 1: 1, 000, 000South AfricaGeology
DS1990-1503
1990
Visser, E.P.Vaneneckevort, W.J.P., Visser, E.P.Photoluminesence microtomography of diamondPhil. Magazine B., Vol. 62, No. 6, December pp. 597-614GlobalDiamond morphology, Luminesence
DS1988-0736
1988
Visser, J.N.J.Visser, J.N.J.Bespeking van 'Die afsetting en verspreiding vanspoel diamante inSuid-Afrika'. *AFR.South African Journal of Geology, Vol. 91, No. 3, September pp. 420-422South AfricaDiamond genesis
DS1996-1485
1996
Visser, J.N.J.Visser, J.N.J., Praekeit, H.E.Subduction, mega shear systems and Late Paleozoic basin development in the African segment of Gondwana.Geol. Rundchau, Vol. 85, No.4, pp. 632-646.Africa, GondwanaTectonics, Subduction
DS200812-1214
2008
Visser, K.Visser, K., Trampert, J., Lebedev, S., Kennett, B.L.N.Probability of radial anisotropy in the deep mantle.Earth and Planetary Science Letters, Vol. 270, 3-4, pp. 241-250.MantleAnisotropy
DS201412-0950
2014
Visser, W.Visser, W.Big or out? Wilfed Visser looks at what 2014 may hold for diamond mining following a year of many changes among the industry's largest players.International Resource Journal, Jan. pp. 70-75.GlobalEconomics
DS1993-1644
1993
Vissers, R.L.M.Van der Wal, D., Vissers, R.L.M.Uplift and emplacement of upper mantle rocks in the western MediterraneanGeology, Vol. 23, No. 12, December pp. 1119-1122.GlobalMantle rocks, Peridotites
DS1993-1645
1993
Vissers, R.L.M.Van der Wal, D., Vissers, R.L.M.Uplift and emplacement of upper mantle rocks in the western MediterraneanGeology, Vol. 21, No. 12, December pp. 1119-1122GlobalMantle, Tectonics
DS1995-2001
1995
Vissers, R.L.M.Vissers, R.L.M., Drury, M.R., Van der Wal, D.Mantle shear zones and their effect on lithosphere strength during continental breakup.Tectonophysics, Vol. 249, No. 3/4, Sept. 30, pp. 155-172.MantleTectonics, Geodynamics
DS1995-2002
1995
Vissers, R.L.M.Vissers, R.L.M., Platt, J.P., Van der Wal, D.Late Orogenic extension of the Betic Cordillera and Alboran Domain: alithospheric view.Tectonics, Vol. 14, No. 4, Aug. pp. 786-803.MoroccoTectonics
DS1996-1461
1996
Vissers, R.L.M.Van der Wal, D., Vissers, R.L.M.Structural petrology of the Ronda Peridotite: deformation historyJournal of Petrology, Vol. 37, No. 1, Feb pp. 23-44GlobalLatered Intrusion, Ronda
DS201910-2306
2019
Vissers, R.L.M.Van Hinsbergen, D.J.J., Torsvik, T.H., Schmid, S.M., Matenco, L.C., Maffione, M., Vissers, R.L.M., Gurer, D., Spakman, W.Orogenic architecture of the Mediterranean region and kinematic reconstruction of its tectonic evolution since the Triassic. AtriaGondwana Research, in press available 427p.Europecraton

Abstract: The basins and orogens of the Mediterranean region ultimately result from the opening of oceans during the early break-up of Pangea since the Triassic, and their subsequent destruction by subduction accommodating convergence between the African and Eurasian Plates since the Jurassic. The region has been the cradle for the development of geodynamic concepts that link crustal evolution to continental break-up, oceanic and continental subduction, and mantle dynamics in general. The development of such concepts requires a first-order understanding of the kinematic evolution of the region for which a multitude of reconstructions have previously been proposed. In this paper, we use advances made in kinematic restoration software in the last decade with a systematic reconstruction protocol for developing a more quantitative restoration of the Mediterranean region for the last 240 million years. This restoration is constructed for the first time with the GPlates plate reconstruction software and uses a systematic reconstruction protocol that limits input data to marine magnetic anomaly reconstructions of ocean basins, structural geological constraints quantifying timing, direction, and magnitude of tectonic motion, and tests and iterations against paleomagnetic data. This approach leads to a reconstruction that is reproducible, and updatable with future constraints. We first review constraints on the opening history of the Atlantic (and Red Sea) oceans and the Bay of Biscay. We then provide a comprehensive overview of the architecture of the Mediterranean orogens, from the Pyrenees and Betic-Rif orogen in the west to the Caucasus in the east and identify structural geological constraints on tectonic motions. We subsequently analyze a newly constructed database of some 2300 published paleomagnetic sites from the Mediterranean region and test the reconstruction against these constraints. We provide the reconstruction in the form of 12 maps being snapshots from 240 to 0 Ma, outline the main features in each time-slice, and identify differences from previous reconstructions, which are discussed in the final section.
DS1989-1561
1989
Vistelius, A.B.Vistelius, A.B., Drubetzkoy, E.R., Faas, A.V.Statistical estimation of mineral age by K-Ar methodMathematical Geology, Vol. 21, No. 8, November pp. 905-920GlobalGeostatistics, Geochronology
DS1991-1807
1991
Vistelius, A.B.Vistelius, A.B., Faas, V.On the precision of age measurements by rubidium-strontium (Rb-Sr) isochrons in nontrivalcasesMathematical Geology, Vol. 23, No. 8, November pp. 999-1044GlobalGeostatistics, Geochronology
DS1970-0442
1971
Viswanadham, C.R.Viswanadham, C.R.The Genesis of Diamond (1971)India Geological Survey Miscellaneous Publishing, No. 19, PP. 141-147.IndiaGenesis
DS1960-1227
1969
Viswanath, N.Viswanath, N.India's Diamond IndustryLapidary Journal, Vol. 23, No. 5, PP. 722-726.India, Panna, GolcondaProduction, History
DS1982-0622
1982
Viswanatha, M.N.Viswanatha, M.N.Economic Potentiality of Gem Tracts of Southern India and Other Aspects of Gem Exploration and Marketing.India Geological Survey Records, Vol. 114, PT. 5, PP. 71-89.IndiaProspecting, Cutting
DS1988-0498
1988
Viswanathan, C.V.K.Nayak, S.S., Viswanathan, C.V.K., Reddy, T.A.K., Rao, B.K.N.New find of kimberlitic rocks in Andhra Pradesh near Maddur,MahaboobnagarDistrictJournal of Geological Society India, Vol. 31, No. 3, March pp. 343-346IndiaBlank
DS200512-1062
2005
Viswanathan, G.Subrahmanyam, A.V., Kumar, V.A., Despati, T., Deshmukh, R.D., Viswanathan, G.Discovery of microdiamonds in beach placers of the east coast, Andhra Pradesh, India.Current Science, Vol. 88, 8, April 25, pp. 1227-1228.India, Andhra PradeshAlluvials, placers, microdiamonds
DS200712-0358
2007
Viswanathan, S.Ghosh, S., Fareeduddin, Viswanathan, S.Chondritic features in a Diamondiferous rock, Majhgawan, Central India.Journal of the Geological Society of India, Vol. 69, 4, p. 863 ( 1p.)IndiaPetrography
DS1992-1609
1992
Viswanathan, T.V.Viswanathan, T.V., Satyanaryana, S.V.Geological setting of Diamondiferous primary and secondary rocks in AndhraPradesh.International Roundtable Conference on Diamond Exploration and Mining, held, pp. 209-211.IndiaGeology, Deposits
DS1960-0716
1966
Viswanathiah, M.N.Naidu, P.R.J., Viswanathiah, M.N.Proceedings of the International Mineralogical Association General Meeting Held New Delhi, Dec. 5th to 22nd. 1964.India Mineralogical Society Volume., 252P.IndiaMineralogy
DS1994-1861
1994
Vita-Finzi, C.Vita-Finzi, C.Seismic folding in coastal south central ChileJournal of Geophy. Res, Vol. 99, B6, June 10, pp. 12, 289-300ChileTectonics, Geophysics -seismics
DS1996-0303
1996
Vita-Finzi, C.Costa, C.H., Vita-Finzi, C.Late Holocene faulting in the southeast Sierras Pampeanas of ArgentinaGeology, Vol. 24, No. 12, Dec. pp. 1127-30GlobalStructure, tectonics, Los Molinos Branch
DS2000-0089
2000
Vita-Finzi, C.Bezzerra, F.H.R., Vita-Finzi, C.How active is a passive margin? paleoseismicity in northeastern BrasilGeology, Vol. 28, No. 7, July, pp. 591-4.BrazilGeophysics - seismics, Tectonics, neotectonics
DS201809-2015
2018
Vitale, A.Di Massa, D., Fedi, M., Florio, G., Vitale, A., Viezzoli, A., Kaminski, V.Joint interpretation of AEM and aeromagnetic dat a acquired over the Drybones kimberlite, NWT ( Canada).Journal of Applied Physics, Vol. 158, pp. 48-56.Canada, Northwest Territoriesdeposit - Drybones

Abstract: We present the joint interpretation of airborne electromagnetic and aeromagnetic data, acquired to study kimberlite pipes. We analyse the data surveyed in 2005 over Drybones Bay, Archean Slave Province of the Northwest Territories, northern Canada. This area hosts a recently discovered kimberlite province with >150 kimberlite pipes. Magnetic and electromagnetic data were each one modelled by 1D inversion. For magnetic data we inverted vertical soundings built through upward continuations of the measured data at various altitudes. The validity of the method was prior verified by tests on synthetic data. Electromagnetic data were processed and inverted using the modified AarhusINV code, with Cole-Cole modelling, in order to take into account induced polarization effects, consisting in negative voltages and otherwise skewed transients. The integrated study of the two kinds of data has led to a better understanding of the structures at depth, even though the comparison between the magnetic and the electromagnetic models shows the different sensitivity of the two methods with respect to the geological structure at Drybones Bay.
DS201709-1965
2017
Vitale-Brovarone, A.Bruguier, O., Bosch, D., Caby, R., Vitale-Brovarone, A., Fernadez, L., Hammor, D., Laouar, R., Ouabadi, A., Abdallah, N., Mechanti, M.Age of UHP metamorphism in the Western Mediterranean: insight from rutile and minute zircon inclusions in a diamond bearing garnet megacryst ( Edough Massif, NE Algeria).Earth and Planetary Science Letters, Vol. 474, pp. 215-225.Africa, Algeriadiamond inclusions

Abstract: Diamond-bearing UHP metamorphic rocks witness for subduction of lithospheric slabs into the mantle and their return to shallow levels. In this study we present U-Pb and trace elements analyses of zircon and rutile inclusions from a diamond-bearing garnet megacryst collected in a mélange unit exposed on the northern margin of Africa (Edough Massif, NE Algeria). Large rutile crystals (up to 300 ?m in size) analyzed in situ provide a U-Pb age of 32.4 ± 3.3 Ma interpreted as dating the prograde to peak subduction stage of the mafic protolith. Trace element analyses of minute zircons (?30 ?m) indicate that they formed in equilibrium with the garnet megacryst at a temperature of 740-810 °C, most likely during HP retrograde metamorphism. U-Pb analyses provide a significantly younger age of 20.7 ± 2.3 Ma attributed to exhumation of the UHP units. This study allows bracketing the age of UHP metamorphism in the Western Mediterranean Orogen to the Oligocene/early Miocene, thus unambiguously relating UHP metamorphism to the Alpine history. Exhumation of these UHP units is coeval with the counterclockwise rotation of the Corsica-Sardinia block and most likely resulted from subduction rollback that was driven by slab pull.
DS1985-0455
1985
Vitaliano, D.B.Milton, C., Vitaliano, D.B.Moissanite Sic, a Geological AberrationGeological Society of America (GSA), Vol. 17, No. 7, P. 665. (abstract.).United States, Gulf Coast, ArkansasMineralogy
DS201905-1020
2019
Viti, C.Cesare, B., Nestola, F., Mugnaioli, E., Della Ventura, G., Peruzzo, L., Bartoli, O., Viti, C., Johnson, T., Erickson, T.I was not born cubic, said low temperature metamorphic garnet. Geophysical Research Abstracts EGRU2019-3091, Vol. 21, 3091, 1p.Europe, Alpsgarnet

Abstract: Garnet is the paradigmatic cubic mineral of metamorphic and igneous rocks, and is generally regarded as optically isotropic. Nonetheless, evident birefringence is observed, particularly in the rare CaFe 3+ hydrogarnets, which is attributed to the coexistence of two or more cubic phases. A weak birefringence, with rare examples of optical sector zoning, has also been documented in much more common Fe 2+-Mg-Mn garnets, but an adequate explanation for its cause is, so far, lacking. Here we show that optically anisotropic garnets are much more widespread than previously thought, both in blueschists and blueschist-facies rocks, as well as in lower greenschist-facies phyllites, but they are frequently overlooked when working with conventional, 30-µm-thick thin sections. Utilizing a multi-technique approach including optical microstructural analysis, BSEM, EMPA, EBSD, FTIR, TEM, EDT and single-crystal XRD, we demonstrate here that the birefringence in these garnets is related to their tetragonal symmetry, that it is not due to strain, and that crystals are twinned according to a merohedral law. We also show that the birefringent garnets from blueschists and phyllites are anhydrous, lacking any hydrogarnet component, and have compositions dominated by almandine (58-79%) and grossular (19-30%) with variable spessartine (0-21%) and very low pyrope (1-7%). Considering the widespread occurrence of optically anisotropic OH-free garnets in blueschists and phyllites, their common low-grade metamorphic origin, and the occurrence of optically isotropic garnets with similar Ca-rich almandine composition in higher-grade rocks, we conclude that garnet does not grow with cubic symmetry in low-temperature rocks (< 400 • C). The tetragonal structure appears to be typical of Fe-Ca-rich compositions, with very low Mg contents. Cubic but optically sector-zoned garnet in a lower amphibolite-facies metapelite from the eastern Alps suggests that preservation of tetragonal garnet is favored in rocks which did not progress to T> ?500 • C, where transition to the cubic form, accompanied by change of stable chemical composition, would take place. Our data show that the crystal-chemistry of garnet, its thermodynamics and, in turn, its use in unravelling petrogenetic processes in cold metamorphic environments need to be reassessed.
DS201911-2514
2019
Viti, C.Cesare, B., Nestola, F., Johnson, T., Mugnaioli, E., Della Ventura, G., Peruzzo, L., Bartoli, O., Viti, C., Erickson, T.Garnet, the archetypal cubic mineral, grows tetragonal.Nature Research, doi.org/10.1038/s41598-019-51214-9Mantlegarnet

Abstract: Garnet is the archetypal cubic mineral, occurring in a wide variety of rock types in Earth’s crust and upper mantle. Owing to its prevalence, durability and compositional diversity, garnet is used to investigate a broad range of geological processes. Although birefringence is a characteristic feature of rare Ca-Fe3+ garnet and Ca-rich hydrous garnet, the optical anisotropy that has occasionally been documented in common (that is, anhydrous Ca-Fe2+-Mg-Mn) garnet is generally attributed to internal strain of the cubic structure. Here we show that common garnet with a non-cubic (tetragonal) crystal structure is much more widespread than previously thought, occurring in low-temperature, high-pressure metamorphosed basalts (blueschists) from subduction zones and in low-grade metamorphosed mudstones (phyllites and schists) from orogenic belts. Indeed, a non-cubic symmetry appears to be typical of common garnet that forms at low temperatures (<450?°C), where it has a characteristic Fe-Ca-rich composition with very low Mg contents. We propose that, in most cases, garnet does not initially grow cubic. Our discovery indicates that the crystal chemistry and thermodynamic properties of garnet at low-temperature need to be re-assessed, with potential consequences for the application of garnet as an investigative tool in a broad range of geological environments.
DS200612-0147
2006
VitorelloBologna, M., Padilha, A.L., Vitorello, Fontes, S.Tectonic insight into a pericratonic subcrustal lithosphere affected by anorogenic Cretaceous magmatism in Brazil inferred from long period magnetotellurices.Earth and Planetary Science Letters, Vol. 241, 3-4, pp. 603-616.South America, BrazilTectonics
DS1995-0577
1995
Vitorello, F.Galvao, L.S., Vitorello, F., Paradella, W.R.Spectroradiometric discrimination of laterites with principal components analysis and additive modelingRemote Sensing of Environment, Vol. 53, No. 2, Aug. pp. 70-75GlobalLaterites, Remote sensing
DS1992-1155
1992
Vitorello, I.Padilha, A.L., Trivedi, N.B., Vitorello, I., Da Costra, J.M.Upper crustal structure of the northeast Parana Basin, Brasil, determined from integrated magnetotelluric and gravity measurementsJournal of Geophysical Research, Vol. 97, No. B3, March 10, pp. 3351-3366BrazilStructure, Crust
DS1995-1429
1995
Vitorello, I.Paradella, W.R., Vitorello, I.Geobotanical and soil spectral investigation for rock discrimination in the Caatinga environmentCanadian Journal of Remote sensing, Vol. 21, No. 1, March pp. 52-59BrazilRemote sensing, Soil, rock discrimination
DS2000-0983
2000
Vitorello, I.Vitorello, I., Padilha, A.L., Bologna, M.S., Padua, M.Upper mantle electrical structures beneath a stable craton and attached collisional zones.Igc 30th. Brasil, Aug. abstract only 1p.BrazilTectonics - craton, Alta Paranabia Igneous Province
DS200512-0103
2005
Vitorello, I.Bologna, M.S., Padilha, A.L., Vitorello, I.Geoelectric crustal structure off the SW border of the Sao Francisco Craton, central Brazil, as inferred from a magnetotelluric survey.Geophysical Journal International, Vol. 162, 2, August pp.357-370.South America, BrazilGeophysics - magnetotelluric
DS201012-0586
2010
Vitorello, I.Pinto, L.G.R.,Banik de Padua, M., Ussami, N., Vitorello, I., Padilha, A.L., Braitenberg, C.Magnetotelluric deep soundings, gravity and geoid in the south Sao Francisco craton: geophysical indicators of cratonic lithosphere rejuvenation and underplating.Earth and Planetary Science Letters, Vol. 297, pp. 423-434.South America, BrazilCarbonatite
DS201012-0633
2010
Vitorello, I.Rodrigues Pinto, L.G., Banik de Padua, M., Ussami, N., Vitorello, I., Lopes Padhilha, A., Braitenberg, C.Magnetotelluric deep soundings, gravity and geoid in the south Sao Francisco craton: geophysical indicators of cratonic lithosphere rejuvenation and crustal underplating.Earth and Planetary Science Letters, Vol. 297, 3-4, pp. 423-434.South America, BrazilGeophysics - magnetotellurics
DS201012-0634
2010
Vitorello, I.Rodrigues Pinto, L.G., Banik de Padua, M., Ussami, N., Vitorello, I., Lopes Padhilha, A., Braitenberg, C.Magnetotelluric deep soundings, gravity and geoid in the south Sao Francisco craton: geophysical indicators of cratonic lithosphere rejuvenation and crustal underplating.Earth and Planetary Science Letters, Vol. 297, 3-4, pp. 423-434.South America, BrazilGeophysics - magnetotellurics
DS201909-2068
2019
Vitorello, I.Padilha, A.L., Vitorello, I., de Padua, M.B., Fuck, R.A.Magnetotelluric images of PaleoProterozoic accretion and Mesoproterozoic to Neoproterozoic reworking processes in the northern Sao Francico craton, central-eastern Brazil.Precambrian Research, in press available, 55p. pdfSouth America, Brazilcraton

Abstract: Broadband and long period magnetotelluric (MT) data were collected along an east-west oriented, 580-km-long profile across the northern São Francisco Craton where extensive Proterozoic and Phanerozoic sedimentary cover and lack of deep-probing geophysical surveys have prevented to establish unequivocally the cratonic character of the Archean-Paleoproterozoic lithosphere. Following dimensionality analyses, the MT dataset was interpreted using both 2-D and 3-D inversion procedures. The near-surface structure is better resolved in the 2-D model due to its finer resolution. A huge upper crustal conductor is found all along the shallow early Neoproterozoic Irecê Basin in the central domain of the craton, extending laterally for approximately 150?km and restricting signal propagation below the basin. Its high conductance is explained by a combination of high porosity and high fluid salinity in the sedimentary package. Another upper crustal conductor is observed on the west side of the profile, interpreted as fractured metasedimentary rocks of the Rio Preto belt thrusted on top of the craton basement during Neoproterozoic marginal collision. The 3-D model explains significantly better the measured data related to deep structure. Contrary to what is expected for a stable cratonic block, the geoelectric model shows pronounced electrical complexity and heterogeneity, an indication that the cratonic lithosphere was multiply reworked in the past by tectonothermal events. Different lithospheric resistive blocks bounded by major conductive zones are identified. Constrained by geochemical and isotopic data, these vertical conductive interfaces are interpreted as cryptic suture zones due to large-scale amalgamation of continents and microcontinents leading to the assembly of the São Francisco Craton in the Paleoproterozoic. The conductivity enhancement is more likely explained by emplacement of sulfides along previous suture zones during mafic magmatism. At upper mantle depths, high conductivity observed below most of the profile indicates that metasomatism or refertilization processes with incompatible elements caused by the Paleoproterozoic subducting slabs and Mesoproterozoic to Neoproterozoic upwelling of deep fluids and melts reworked this portion of the craton mantle.
DS200612-1485
2006
Vitos, L.Vitos, L., Magyati-Kope, B., Ahuja, R., Kollar, J., Grimvall, G., Johansson, B.Phase transformations between garnet and perovskite phases in the Earth's mantle: a theoretical study.Physics of the Earth and Planetary Interiors, Vol. 156, 1-2, pp. 108-116.MantleLower mantle, majorite, geophysics -seismic
DS1984-0370
1984
Vitozhents, G.CH.Ilupin, I.P., Vitozhents, G.CH., Kulighin, V.M.Sodium, Potassium, Cesium, Barium in Kimberlites of SiberiaGeokimiya., No. 7, JULY PP. 1014-1019.Russia, SiberiaGeochemistry, Kimberlites, Sodium, Cesium, Barium
DS1985-0301
1985
Vitozhents, G.CH.Ilupin, I.P., Vitozhents, G.CH., Kuligin, V.M.Instrumental neutron activation analysis for sodium, potassium, cesium and barium in Siberian kimberlitesGeochemistry International, Vol. 22, No. 1, pp. 50-55RussiaBlank
DS1940-0061
1942
Vitt, G.N.Vitt, G.N.Letter to R.j. Thoenen Concerning Proposed Pilot Plant at Arkansas MineNorth American Diamond Corp. (chicago), 2P. UNPUBL.United States, Gulf Coast, Arkansas, PennsylvaniaEvaluation News Item
DS1940-0077
1943
Vitt, G.N.Vitt, G.N.Memorandum on Diamond Content and Kinds of Murfreesboro Diamondiferous Peridotite Pipe.North American Diamond Corp. (chicago), 8P. UNPUBL.United States, Gulf Coast, Arkansas, PennsylvaniaDiamond Production, Evaluation
DS1990-0289
1990
Vittadin, A.Casarin, M., Granozzi, G., Tondello, E., Vittadin, A.A molecular cluster approach to the electronic structure of anomalous muonium in diamondChem. Phys, Vol. 148, No. 2-3, December 1, pp. 183-192GlobalDiamond morphology, MuoniuM.
DS1988-0737
1988
Vitte, L.V.Vitte, L.V., Vasilevskii, A.N.The question of tectonic position and forms of manifestations of alkaline ultrabasic magmatism In the crust of the Siberian PlatformSoviet Geology and Geophysics, Vol. 29, No. 5, pp. 46-54RussiaAlkaline rocks, Tectonics
DS1991-1008
1991
Vityk, M.O.Lomov, S.B., Vityk, M.O.Cracking aureoles around fluid inclusions in Carpathian MarmaroshdiamondsGeochemistry International, Vol. 28, No. 7, pp. 125-128RussiaDiamond inclusions, Diamond morphology
DS1994-1862
1994
Vityk, M.O.Vityk, M.O., Bodnar, R.J., Schmidt, C.S.Fluid inclusions as tectonothermomobarometers: relation between P-T history and reequilibrium morphologyGeology, Vol. 22, No. 8, August pp. 731-734GlobalGeothermometry, Crustal thickening
DS1995-2003
1995
Vityk, M.O.Vityk, M.O., Bodnar, R.J., Dudok, I.V.Natural and synthetic re-equilibration textures of fluid inclusions in quartz (Marmarosh diamonds)refill-European Journ. of Mineralogy, No. 5, pp. 1071-1088.GlobalQuartz - imitation diamonds
DS1996-1486
1996
Vityk, M.O.Vityk, M.O., Bodnar, R.J., Dudok, I.V.Fluid inclusions in Marmarosh diamonds: evidence for tectonic history Of the folded Carpathian Mountains.Tectonophysics, Vol. 255, No. 1-2, April 20, pp. 163-UKraineMarmarosh - not diamonds, Tectonics
DS1998-0159
1998
Vityk, M.O.Bratus, M.D., Zinchuk, N.N., Krouse, G.R., Vityk, M.O.Crystallization conditions and sulfur, carbon and oxygen isotopic systematics of sulfide calcite AssociationGeochemistry International, Vol. 36, No. 3, pp. 222-228.Russia, YakutiaGeology, diamond morphology, fluid inclusions, Deposit - Udachnaya, Geochronology
DS1988-0254
1988
Vityuk, V.I.Getman, A.F., Andreev, A.V., Vityuk, V.I.Preparation of diamonds from various carbonaceous materials in the presence of metallic melts.(Russian)Sverkhtverd. Mater., (Russian), No. 6, pp. 6-8GlobalDiamond synthesis
DS200812-1016
2008
Viveira Conceicao, R.Schilling, M.E., Carlson, R.W., Viveira Conceicao, R., Dantas, Bertotto, KoesterRe-Os isotope contraints on subcontinental lithosphere mantle evolution of southern South America.Earth and Planetary Science Letters, Vol. 268, 1-2, April 15, pp. 89-101.South America, RodiniaGeochronology - xenoliths
DS201112-1093
2010
Viveira de Almeida, V.Viveira de Almeida, V., De Assis Janasi, V., Svisero, D.P.Mathiasita e priderita em xenolitos mantelicos do kimberlito Limeira, Monte Carmelo, Minas Gerais.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 88.South America, Brazil, Minas GeraisPetrology
DS201312-0080
2013
Vivian, G.Bezzola, M., Hrkac, C., Vivian, G.Kennady North property: potential with the complexity. Faraday and Kelvin2013 Yellowknife Geoscience Forum Abstracts, p. 11. abstractCanada, Northwest TerritoriesDeposit - Faraday, Kelvin
DS201312-0941
2013
Vivian, G.Vivian, G., Hrkac, C., Kalkowski, T.3D till sampling: a committed strategy for the hidden kimberlite. 2013 Yellowknife Geoscience Forum Abstracts, p. 30. abstractCanada, Northwest TerritoriesGeophysics - North Arrow
DS201412-0047
2014
Vivian, G.Belcourt, G., Hrkac, C., Vivian, G.Kennady North property: 2014 geophysical update.2014 Yellowknife Geoscience Forum, P. 14, abstractCanada, Northwest TerritoriesGeophysics
DS201412-0055
2014
Vivian, G.Bezzola, M., Hrkac, C., Vivian, G.A tunnel to the future: the preliminary geology of the Kelvin kimberlite. ( Kennady)2014 Yellowknife Geoscience Forum, p. 17, abstractCanada, Northwest TerritoriesDeposit - Kelvin
DS201412-0619
2014
Vivian, G.Nelson, L., Bezzola, M., Hrkac, C., Vivian, G.Kennady North property: 2014 field season update.2014 Yellowknife Geoscience Forum, p. 50, abstractCanada, Northwest TerritoriesDeposit - Kennady North
DS201512-1988
2015
Vivian, G.White, D., Bezzola, M., Hrkac, C., Vivian, G.Kennady North property: 2015 field season update.43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 109.Canada, Northwest TerritoriesDeposit - Kennady North

Abstract: The Kennady North Property, wholly owned by Kennady Diamonds Inc. (KDI) is located 300 km northeast of Yellowknife adjacent to the DeBeers/Mountain Province Gahcho Kué mine site. Exploration on the property dates back to the early 90’s, during which time several kimberlites were discovered. Since 2012 Kennady Diamonds has completed a number of geophysical, hand and RC till sampling and diamond drill programs. In 2015, KDI completed a large diameter reverse circulation drill program to bulk sample the southern lobe of the Kelvin kimberlite. Following the RC program, diamond drilling and ground geophysical surveys continued in the Kelvin-Faraday Corridor (KFC) and at various exploration targets on the property including the MZ Dyke and Doyle Sill. The field season started in January with the completion of the Kelvin camp and the construction of the RC drill icepad on Kelvin Lake. The pad and a seasonal spur road off the Gahcho Kue seasonal road were completed to coincide with the opening of the Tibbit-Contwoyto winter road and facilitated the mobilization of two large diameter RC rigs operated by Midnight Sun Drilling Inc. to the property. A total of 446 tonnes of the Kelvin kimberlite were obtained via RC drilling between February 19 and April 2. The bulk sample was processed via DMS at the Saskatchewan Research Council in Saskatoon. One diamond drill commenced drilling prior to the RC program and two other drills commenced on the heels of the RC program. A total of 31,000 meters of NQ and HQ core have been drilled during 2015 to the end of October. Drilling at Kelvin has focused on geotechnical and related environmental baseline work as well as further delineation of the pipe-like body with the aim of generating a NI43-101 compliant resource in early 2016. Diamond drilling at the Faraday group of kimberlites delineated the Faraday 1 and Faraday 2 kimberlites. These pipe-like bodies share a similar pipe-like structure and internal geology to the Kelvin kimberlite. Aurora conducted 8848 stations of ground gravity and 521.32 line-kilometers of OhmmapperTM capacitively coupled resistivity in the KFC, MZ dyke, and Doyle Sill during March and April. A 87 line-kilometer bubble seismic survey over the Kelvin, Faraday and MZ complexes was conducted in September. Kennady Diamond Inc. is very encouraged by the exploration results to date and anticipates a successful and exciting 2016.
DS1970-0082
1970
VivienneGeorge, Ward, VivienneDiamonds of CherokeeTreasure World, Publishing P.o. Drawer L, Conroe Texas, 60P.United States, California, West CoastKimberley, History
DS1993-1675
1993
Viytkovskiy, Yu.B.Viytkovskiy, Yu.B., Podgayetskiy, A.V., Zinchuk, N.N., KotelnikovIlmenite xenoliths and groundmass of kimberlite from the Mir and Sytykanskaya pipes.Doklady Academy of Sciences USSR, Earth Science Section, Vol. 317, pp. 191-195.Russia, YakutiaXenolith mineralogy, Deposits
DS1993-1676
1993
Vizan, H.Vizan, H., Mena, M., Vilas, J.F.Pangea, the geoid, and the paths of virtual geomagnetic poles during polarity reversalsJournal of South American Earth Sciences, Vol. 6, No. 4, November pp. 253-266PangeaPaleomagnetism
DS200812-1215
2008
Vizan, H.Vizan, H., Van Zele, M.A.Jurassic Cretaceous intermediate virtual geomagnetic poles Pangean subduction zones.Earth and Planetary Science Letters, Vol. 266, 1-2, pp. 1-13.MantleSubduction
DS2001-1166
2001
Vlaar, N.Trampert, J., Vacher, P., Vlaar, N.Sensitivities of seismic velocities to temperature, pressure and composition in the lower mantle.Physical Earth and Planetary Interiors, Vol. 124, No. 3-4, Aug. pp. 255-67.MantleGeophysics - seismics
DS1994-1863
1994
Vlaar, N.JVlaar, N.J, Vankeken, P.E., Vandenbe, A.P.Cooling of the earth in the Archean -consequences of pressure release melting in a hotter mantle.Earth and Planetary Sciences, Vol. 121, No. 1-2, January pp. 1-18.MantleMelting
DS1988-0738
1988
Vlaar, N.J.Vlaar, N.J.Subduction of young lithosphere: lithospheric doubling, a possiblescenarioD. Reidel Publishing Co., Nato Series, Asi C, Math. Phys. Sci. Vol. 258, pp. 65-74. p. 71 only mentions kimberlitesGlobalMantle, Tectonics
DS1989-0274
1989
Vlaar, N.J.Cloetingh, S., Wortel, R., Vlaar, N.J.On the initiation of subduction zonesPageophy., (Pure and Applied Geophysics), Vol. 129, No. 1-2, pp. 7-25. Database # 17531BasinOphiolite, Plate tectonics-subduction
DS1994-1864
1994
Vlaar, N.J.Vlaar, N.J., Van Keken, .E., Van den Berg, A.P.Cooling of the Earth in the Archean: consequences of pressure release melting in a hotter mantleEarth and Planetary Science Letters, Vol. 121, No. 1-2, January pp. 1-18MantleArchean, Melting
DS1994-1865
1994
Vlaar, N.J.Vlaar, N.J., Van Keken, P.E., Van den Berg, A.P.Cooling of the earth in thr Archean: consequences of pressure release melting in a hotter mantle.Earth and Planetary Science Letters, Vol. 121, No. 1/2, January pp. 1-18.MantleArchean, Hot spots
DS1998-0325
1998
Vlaar, N.J.De Smet, J.H., Van den Berg, A.P., Vlaar, N.J.Stability and growth of continental shields in mantle convection models including recurrent melt production.Tectonophysics, Vol. 296, No. 1-2, . Oct. 30, pp. 15-30.MantleCraton, Magmatism
DS1999-0132
1999
Vlaar, N.J.Cizkova, H., Cadek, O., Vlaar, N.J.Can lower mantle slablike seismic anomalies be explained by thermal coupling between upper and lower.Geophysical Research Letters, Vol. 26, No. 10, May 15, pp. 1501-8.MantleGeophysics - seismics
DS1999-0161
1999
Vlaar, N.J.De Smet, J.H., Van Den Berg, A.P., Vlaar, N.J.The evolution of continental roots in numerical thermo-chemical mantle convection models including ...Lithos, Vol. 48, No. 1-4, Sept. pp. 153-70.MantleGeothermometry - model, Melting - differentiation of partial
DS2000-0216
2000
Vlaar, N.J.De Smet, J., Van den Berg, A.P., Vlaar, N.J.Early formation and long term stability of continents resulting from decompression melting convecting mantle.Tectonophysics, Vol. 322, No. 1-2, pp. 19-33.MantleMagmatism - convection
DS2000-0217
2000
Vlaar, N.J.De Smet, J., Van den Berg, A.P., Vlaar, N.J.Early formation and long term stability of continents resulting decompression melting in convecting mantle.Tectonophysics, Vol.322, No.1-2, July10, pp.19-34.MantleMagmatism, Convection
DS2000-0984
2000
Vlaar, N.J.Vlaar, N.J.Continental emergence and growth on a cooling earthTectonophysics, Vol.322, No.1-2, July10, pp.191-MantleCraton, Tectonics
DS2001-1184
2001
Vlaar, N.J.Van Hunen, J., VandenBerg, A.P., Vlaar, N.J.Latent heat effects of the major mantle phase transitions on low angle subduction.Earth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 125-35.MantleSubduction
DS2002-0344
2002
Vlaar, N.J.Czkova, H., Van Hunen, J., Van denberg, A.P., Vlaar, N.J.The influence of rheological weakening and yield stress on the interaction of slabs with the 670 km discontinuity.Earth and Planetary Science Letters, Vol.199,3-4,pp.447-57.MantleBoundary, Subduction
DS2002-1644
2002
Vlaar, N.J.Van Hunen, J., Van den Berg, A.P., Vlaar, N.J.The impact of the South American plate motion and the Nazca Ridge subduction on the flat subduction below south Peru.Geophysical Research Letters, Vol. 29, 14, DOI 10.1029/2001GL014004PeruTectonics - subduction
DS200512-1120
2004
Vlaar, N.J.Van Hunen, J., Van den Berg, A.P., Vlaar, N.J.Various mechanisms to induce present day shallow flat subduction and implications for the younger Earth: a numerical parameter study.Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 159-194.MantleSubduction
DS200512-1124
2004
Vlaar, N.J.Van Thiemen, P., Van den Berg, A.P., Vlaar, N.J.On the formation of continental silicic melts in thermochemical mantle convection models: implications for early Earth.Tectonophysics, Vol. 394, 1-2, pp. 111-138.MantleGeothermometry
DS200612-1469
2005
Vlaar, N.J.Van Thielen, P., VanSummeren, J., VanderHilst, R.D., VandenBerg, A.P., Vlaar, N.J.Numerical study of the origin and stability of chemically distinct reservoirs deep in the Earth's mantle.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 117-136.MantleGeochemistry
DS1994-1808
1994
Vlach, S.R.F.Ulbrich, M.N.C., Maringolo, V., Vlach, S.R.F.Xenocrysts in mafic dikes from the Fernando de Noronha ArchipelagoInternational Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 36-38.BrazilAlkaline rocks
DS201112-1021
2010
Vlach, S.R.F.Svisero, D.P.,Vlach, S.R.F.Composicao e origem de minerais resistatos da regiao de Coromandel e areas adjacentes, Minas Gerais.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 63-4.South America, Brazil, Minas GeraisIndicator Mineralogy
DS1994-1784
1994
Vladimirov, A.G.Titov, A.V., Vladimirov, A.G., Chupin, V.P., Mayorova, O.Evolution and crystallization conditions of shoshonite and latite melts Kyzylrabat volcanic structure, Pamirs.Doklady Academy of Science USSR, Earth Science Section, Vol. 328, No. 1, Nov. pp. 103-107.Russia, PamirShoshonite, Alkaline rocks
DS1996-0736
1996
Vladimirov, A.G.Khain, V.E., Tychkov, S.A., Vladimirov, A.G.Collision orogeny: a model for the detachment of a subducted oceanic lithosphere plate as a result ..Russian Geology and Geophysics, Vol. 37, No. 1, pp. 3-13RussiaTectonics, Subduction, mantle diapir
DS1996-0737
1996
Vladimirov, A.G.Khain, V.E., Tychkov, S.A., Vladimirov, A.G.Collision orogeny: a model for detachment of subducted oceanic lithosphere plate - continental collisionRussian Geology and Geophysics, Vol. 37, No. 1, pp. 3-13.RussiaSubduction, Mantle diapir
DS200412-2066
2004
Vladimirov, A.G.Vrublevskii, V.V., Zhuravlev, D.Z., Gertner, I.F., Krupchatnikov, V.I., Vladimirov, A.G., Rikhvanov, L.P.Sm Nd isotopic systematics of alkaline rocks and carbonatites from the Edelveis Complex, Northern Chuya Range, Gornyi Altai.Doklady Earth Sciences, Vol. 397, 6, July-August pp. 870-874.RussiaGeochronology
DS1960-0106
1960
Vladimirov, B.M.Vladimirov, B.M.On the Terminology of the Diamondiferous Kimberlites of Yakutia.Geologii i Geofiziki, No. 11.RussiaBlank
DS1960-0198
1961
Vladimirov, B.M.Vladimirov, B.M., Znamerovsky, V.I.Kimberlite Pipes in the South of the Siberian PlatformDoklady Academy of Sciences Nauk SSSR., Vol. 139, No. 2, PP. 858-860.RussiaBlank
DS1960-0285
1962
Vladimirov, B.M.Odintsov, M.M., Tverdokhlebov, V.A., Vladimirov, B.M., Ilyukhi.Structure, Volcanism and Diamondiferous Deposits in the Irkutsk Amphitheatre.Moscow: Izdat Nauka., 179P.Russia, IrkutskKimberlite, Kimberley
DS1960-0722
1966
Vladimirov, B.M.Odintsov, M.M., Vladimirov, B.M.Some General Regularities of Spacial Distribution of Kimberlites and Diamond Bearing Occurrences in the Earth's Crust.In: Problems of Genesis And Regularities of Distribution Of, MOSCOW: NEDRA.RussiaBlank
DS1960-1005
1968
Vladimirov, B.M.Odintsov, M.M., Vladimirov, B.M., Tverdokhledeboy, I.Regularities of Kimberlite Distribution in the Earth's CrustInternational Geological Congress 23RD., PP. 139-146.RussiaBlank
DS1970-0144
1970
Vladimirov, B.M.Mikheyenko, V.I., Vladimirov, B.M., Nenashev, N.I., et al.A Cobble of diamond Bearing Eclogite from Kimberlite of the Mir Pipe.Doklady Academy of Science USSR, Earth Science Section., Vol. 190, No. 1-6, PP. 179-181.RussiaBlank
DS1970-0443
1971
Vladimirov, B.M.Vladimirov, B.M., et al.Geology and Petrography of Eruptive Rocks of the Southwest guinea Liberia Shield.Moscow: Akad. Nauk Sssr, Sib. Otd. Institute Zemnoy Kory, 242P.GlobalKimberlite
DS1975-0428
1976
Vladimirov, B.M.Vladimirov, B.M., et al.Deep seated Inclusions from Kimberlites, Basalts, and Kimberlite-like Rocks.Moscow: Nauka., RussiaKimberlite, Kimberley, Janlib
DS1981-0391
1981
Vladimirov, B.M.Solovyeva, L.V., Vladimirov, B.M., Kostrovitskiy, S.I.Autoliths of Kimberlites and their GenesisIzvest. Akad. Nauk Sssr Geol. Ser., No. 7, PP. 5-18.RussiaGenesis
DS1981-0421
1981
Vladimirov, B.M.Vladimirov, B.M.Principles and Schemes for a Detailed Classification of Kimberlites.In: Odintsov, M.m. Editor., PP. 14-32.RussiaBlank
DS1982-0118
1982
Vladimirov, B.M.Brandt, S.B., Vladimirov, B.M., et al.Strontium Isotopic Systematics in Kimberlites of YakutiaSoviet Geology, No. 1, PP. 94-103.RussiaGeochemistry, Isotopes, Kimberlite
DS1982-0499
1982
Vladimirov, B.M.Podvysotskiy, V.T., Vladimirov, B.M., Ivanov, S.I., Kotelnikov.Serpentinization of KimberliteDoklady Academy of Sciences ACAD. NAUK USSR, EARTH SCI. SECTION., Vol. 256, No. 1-6, PP. 87-90.RussiaAlteration, Petrography
DS1984-0699
1984
Vladimirov, B.M.Solovieva, L.V., Vladimirov, B.M., Zavialova, L.L., Barankevich.Deep Seated Inclusions of the Complex Type from the Udachnaia Kimberlite Pipe.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 277, No. 2, PP. 461-466.RussiaBlank
DS1986-0298
1986
Vladimirov, B.M.Gotovtsev, V.V., Vladimirov, B.M., et al.System of conjugated kimberlite bodies of the Udachnaya piperegion.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 286, No. 6, pp. 1481-1487RussiaBlank
DS1986-0458
1986
Vladimirov, B.M.Kostrovitskiy, S.I., Vladimirov, B.M., Solovyeva, L.V., FiveyskayaAssociations of mineral inclusions in olivine from kimberliteDoklady Academy of Science USSR, Earth Science Section, Vol. 276, January pp. 114-117RussiaUdachnaya, Mineralogy
DS1986-0773
1986
Vladimirov, B.M.Solovyeva, L.V., Vladimirov, B.M., Zavyalova, L.L., Barankevich, V.V.Complex deep seated inclusions from the Udachnaya kimberlite pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 277, March pp. 77-82RussiaYakutia, Analyses
DS1986-0842
1986
Vladimirov, B.M.Vladimirov, B.M., Solovyeva, L.V.A comparative study of fluid and melt inclusions, theircompositions, time-space relations, genesis and tectoniccontrolProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 95-96GlobalClassification
DS1987-0702
1987
Vladimirov, B.M.Solovyeva, I.V., Vladimirov, B.M., Kiselev, A.I.Types of mantle metasomatism and their probable connection with the lithospheric processes.(Russian)Metasomatism and Ore genesis, Theses of reports, The VI all union, pp. 36-37. AbstractRussiaKimberlite, Petrology
DS1988-0197
1988
Vladimirov, B.M.Egorov, K.N., Vladimirov, B.M., Zaborovskii, V.V., et al.Potassium trachyte vein in the region of the Udachnaya kimberlite pipe(yakutia). (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 298, No. 1, pp. 186-189RussiaBlank
DS1989-0418
1989
Vladimirov, B.M.Feokistov, G.D., Vladimirov, B.M.Characteristics of distribution of silicon contents ingarnets Of kimberlite pipes.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 308, No. 2, pp. 436-439RussiaPlacers, Garnet analyses
DS1989-1668
1989
Vladimirov, B.M.Yegorov, K.N., Vladimirov, B.M., Zaborovskiy, V.V., et al.Find of a potassic trachyte dike near the Udachnaya kimberlite pipe, Yakutia #1Doklady Academy of Science USSR, Earth Science Section, Vol. 298, No. 1-6, pp. 116-119RussiaDeposit -Udachnaya, Trachyte dike
DS1989-1669
1989
Vladimirov, B.M.Yegorov, K.N., Vladimirov, B.M., Zaborovskiy, V.V., NasurdinovFind of a potassic trachyte dike near the Udachnaya kimberlite pipe, Yakutia #2Doklady Academy of Science USSR, Earth Science Section, Vol. 298, No. 1-6, April pp. 116-118RussiaPetrography, Trachyte
DS1991-0432
1991
Vladimirov, B.M.Egorov, K.N., Vladimirov, B.M., Bogdanov, G.V.Geology, petrology and mineral composition of the Udachnaya kimberlite ore complex (Yakutia)Proceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 498-500RussiaPetrology, Deposit -Udachnaya
DS1991-0474
1991
Vladimirov, B.M.Feokistov, G.D., Vladimirov, B.M.Trend of SiO2 in garnets from kimberlite pipesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, p. 501RussiaMineral chemistry, Garnets
DS1991-0475
1991
Vladimirov, B.M.Feokistov, G.D., Vladimirov, B.M.Distribution of silica concentrations in garnets of kimberlite pipesDoklady Academy of Science USSR, Earth Science Section, Vol. 308, No. 5, pp. 154-157RussiaMineralogy, Silica/garnets
DS1991-0476
1991
Vladimirov, B.M.Feoktistov, G.D., Vladimirov, B.M.Petrochemical types of kimberlites on the Siberian PlatformSoviet Geology and Geophysics, Vol. 32, No. 9, pp. 20-25Russia, SiberiaGeochemistry, Kimberlites
DS1991-1538
1991
Vladimirov, B.M.Sekerin, A.P., Menshagin, V., Vladimirov, B.M., Lashchenov, V.A.Precambrian diamond bearing veined bodies from southwest of the SiberianPlatformProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 543-544RussiaVeins, lamproite, Chrome spinellids, geochronology
DS1991-1808
1991
Vladimirov, B.M.Vladimirov, B.M., Egorov, K.N., Maslovskaya, M.N., DneprovskayaBasaltic and mica kimberlites of the Siberian platform and their time space and genetic relationshipsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 573-575RussiaGeochronology, Deposit -Udachnya
DS1995-0532
1995
Vladimirov, B.M.Feoktistov, G.D., Vladimirov, B.M., Egorov, K.N., KonevKimberlite and lamproite comparative petrogeochemistryProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 152-54.Russia, SiberiaLamproite, Petrology
DS1996-0454
1996
Vladimirov, B.M.Feoktistov, G.D., Vladimirov, B.M., Egorov, K.N., Konev, A.Petrochemical comparison of kimberlites and some lamproites of the Siberian Platform and Australia.Russian Geology and Geophysics, Vol. 37, No. 10, pp. 26-33.Russia, Siberia, AustraliaLamproites, Petrology
DS1988-0739
1988
Vladimirov, Y.V.Vladimirov, Y.V., Gushchin, V.A., Denyak, V.V., Evseev, I.G., et al.Polarization of electromagnetic radiation in motion of ultra- relativistic electrons near a crystal axis ofdiamond.(Russian)Soviet Journal of Nuc. R., (Russian), Vol. 48, No. 4, Oct. pp. 768-769RussiaDiamond morphology
DS1989-0753
1989
Vladimirova, M.V.Kavasnitsa, V.N., Zakharchenko, O.D., Vladimirova, M.V., Taran, M.N.The features of skeletal cubes of natural diamond.(Russian)Mineralogischeskiy Sbornik, (L'vov), (Russian), Vol. 43, No. 2, pp. 86-90Russia, YakutiaDiamond morphology, Mineralogy
DS1984-0426
1984
Vladimrov, B.M.Kostrovitsky, S.I., Vladimrov, B.M., Solovyeva, L.V.Association of Mineral Inclusions in Olivine in Kimberlites.(russian)Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol. 276, No. 2, pp. 451-454RussiaMineralogy
DS1991-1631
1991
Vladirmirov, B.M.Solovjeva, L.V., Vladirmirov, B.M.Cognate suite of garnet clinopyroxenite -olivine websterite lherzolite From the Udachanya kimberlite pipe, YakutiaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 560-561RussiaMineral chemistry, Lherzolite
DS201012-0165
2010
Vladkar, S.Doroshkevich, A.G., Ripp, G., Vladkar, S.Newania carbonatites, western India:example of mantle derived magnesium carbonatites.Mineralogy and Petrology, Vol. 98, 1-4, pp. 283-295.IndiaCarbonatite
DS2001-1204
2001
Vladkar, S.G.Vladkar, S.G.Carbonatites of India: an overviewAlkaline Magmatism -problems mantle source, pp. 257-71.IndiaCarbonatite, Review
DS2002-1672
2002
Vladkar, S.G.Vladkar, S.G., Ghose, I.U rich pyrochlore in carbonatite of Newania, RajasthanNeues Jahrbuch fur Mineralogie - Monatshefte, No.3, March,ppp.97-106.IndiaCarbonatite
DS200812-1220
2008
Vladkar, S.G.Vladykin, N.V., Vladkar, S.G., Miyazaki, T., Mohan, V.R.Geochemistry of bentonite and associated carbonatites of Sevathur, Jogipatti and Samalpatti, Tamil Nadu, South India and Murun Massif, Siberia.Journal of the Geological Society of India, Vol. 72, 3, pp. 312-324.India, RussiaCarbonatite
DS201507-0339
2015
Vladkar, S.G.Vladkar, S.G.Mineralogy and geochemistry of fenitized nephelinites of the Amba Dongar complex, Gujarat.Journal of the Geological Society of India, Vol. 85, 1, pp. 87-97.IndiaNephelinite
DS202203-0369
2022
Vladkar, S.G.Vladkar, S.G.Nb-bearing minerals in Sirwasan carbonatite, Chhota Udapur, Gujarat, India.Journal of the Geological Society of India, Vol. 98, 2, p. 285. (1p)Indiadeposit - Sirwasan
DS2000-0319
2000
Vladova, G.L.Gatinskii, Y.G., Vladova, G.L., Rozhkova, V.V.Seismicity and metallogeny of convergent plate boundaries in subduction zones.Doklady Academy of Sciences, Vol. 371a, No. 3, Mar-Apr. pp. 583-7.MantleGeophysics - seismics, Subduction
DS2001-0055
2001
VladykinAshchepkov, I.V. , Vladykin, Gerasimov, Saprykin, et al.Temperature gradient and structure of the lithospheric block beneath the southeastern margin of Siberia cratonDoklady Academy of Sciences, Vol. 378, No. 4, May-June pp. 530-35.Russia, Siberia, Aldan shieldXenolith evidence from kimberlites, Geothermometry
DS2001-0056
2001
VladykinAshchepkov, I.V., Gerasimov, Saprykin, Vladykin, AnoshinTrace element composition of deep seated mineral inclusions from Aldan lamproites: first la ICP MS studyGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.5, abstract.RussiaLamproites, Amga River basin
DS2001-0058
2001
VladykinAshchepkov, L.V., Vladykin, Gerasimov, SaprykinPetrology and mineralogy of disintegrated mantle inclusions of kimberlite like diatremes from Aldan areaAlkaline Magmatism -problems mantle source, pp. 161-76.Russia, Aldan shieldMantle reconstructions - Chompolo field
DS2003-0976
2003
VladykinMorikiyo, T., Kostrovitsky, S.I., Weerakoon, M.W.K., Miyaazaki, T., VladykinSr and Nd isotopic difference between kimberlites and carbonatites from the Siberian8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractRussia, YakutiaKimberlite petrogenesis, Geochronology - four zones
DS200512-0031
2002
VladykinAshchepkov, I.V., Saprykin, A.I., Gerasim, Khmeintkova, Cheremenykk, Safonova, Rasskazov, Kinolin, VladykinPetrochemistry of mantle xenoliths from Sovgavan Plateau, Far East Russia.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 213-222.RussiaXenoliths
DS200512-0036
2004
VladykinAshchepkov, I.V., Vladykin, Rotman, Loginova, Afanasiev, Palessky, Saprykin, Anoshin, Kuchkin, KhmelnikovaMir and Internationalnaya kimberlite pipes - trace element geochemistry and thermobarometry of mantle minerals.Deep seated magmatism, its sources and their relation to plume processes., pp. 194-208.RussiaGeobarometry - Mir, International
DS200612-0046
2005
VladykinAshchepkov, I.V., Vladykin, Rotman, Afansiev, Loginova, Kuchkin, Palessky, Nikolaeva, Saprykin, AnoshinVariations of the mantle mineralogy and structure beneath Upper - Muna kimberlite field.Problems of Sources of Deep Magmatism and Plumes., pp. 170-187.RussiaMineralogy
DS200612-0047
2006
VladykinAshchepkov, I.V., Vladykin, Sobolev, Pokhilenko, Rotman, Logvinova, Afanasiev, Pokhilenko, KarpenkoReconstruction of the mantle sequences and the structure of the feeding and vein magmatic systems beneath the kimberlite fields of Siberian platform.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 79-103.Russia, SiberiaDyke systems
DS200612-0048
2006
VladykinAshchepkov, I.V., Vladykin, Sobolev, Pokhilenko, Rotman, Logvinova, Afanasiev, Pokhilenko, KarpenkoVariations of the oxygen conditions in mantle column beneath Siberian kimberlite pipes and it's application to lithospheric structure of feeding systems.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 125-144.Russia, SiberiaRedox
DS200612-0740
2006
VladykinKovalenko, V.I., Yarmolyuk, Salnikova, Kozlovski, Kotov, Kovach, Vladykin, Savatenkov, V.M., Ponomarchuk, V.A.Geology and age of Khan-Bogdinsky massif of alkaline granitoids in southern Mongolia.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 17-45.Asia, MongoliaAlkaline rocks, granites
DS200812-0051
2008
VladykinAshchepkov, I.V., Pokhilenko, Vladykin, Rotam, Afansiev, Logvinova, Kostrovitsky, Karpenko, KuliginReconstruction of mantle sections beneath Yakutian kimberlite pipes using monomineral thermobaraometry.Geological Society of London, Special Publication, SP 293, pp. 335-352.RussiaGeothermometry
DS200812-0052
2007
VladykinAshchepkov, I.V., Vladykin, Pkhilenko, Logvinova, Palessky, Afansiev, Alymova, Stegnitsky, Khmelnikova RotamanVariations of ilmenite compositions from Yakutian kimberlites and the problem of their origin.Vladykin Volume 2007, pp. 71-89.Russia, YakutiaIlmenite, kimberlite
DS200912-0016
2009
VladykinAschepokov, L., Logvinova, A., Kuligin, Pokhilenko, Vladykin, Mityukhin, Alymova, Malygina, VishnyakovaClinopyroxene eclogite peridotite thermobarometry of the large Yakutian kimberlite pipes.Goldschmidt Conference 2009, p. A58 Abstract.Russia, YakutiaThermobarometry
DS201012-0016
2010
VladykinAshchepkov, I., Afanasiev, Vladykin, Pokhilenko, Ntaflos, Travin, Ionov, Palessky, Logvinova, Kuligin, MityukhinReasons of variations of the mineral compositions of the mantle rocks beneath the Yakutian kimberlite province.International Mineralogical Association meeting August Budapest, abstract p. 141.Russia, YakutiaGeothermometry
DS201012-0018
2010
VladykinAshchepkov, I.V., Pokhilenko, Vladykin, Logvinova, Afansiev, Kuligin, Malygina, Alymova, KostrovitskyStructure and evolution of the lithospheric mantle beneath Siberian Craton, theromobarometric study.Tectonophysics, Vol. 485, pp. 17-41.RussiaGeothermometry
DS201012-0019
2009
VladykinAshchepkov, I.V., Rotman, Nossyko, Somov, Shimupi, Vladykin, Palessky, Saprykin, KhmelnikovaComposition and thermal structure of mantle beneath the western part of the Congo-Kasai craton according to xenocrysts from Angola kimberlites.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., p. 158-180.Africa, AngolaGeothermometry
DS201012-0020
2009
VladykinAshchepkov, Vladykin, Pokhilenko, Logvinova, Kuligin, Pokhilenko, Malgina, Alymova, Mityukhin, KopylovaApplication of the monomineral thermobarometers for the reconstruction of the mantle lithosphere structure.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., p. 98-116.MantleGeothermometry
DS201112-0037
2010
VladykinAshchepkov, Ntaflos, Vladykin, Ionov, Kuligin, Malygina, Pokhilenko, Logvinova, Mityukhin, Palessky, Khmelnikova, RotmasDeep seated xenoliths from the phlogopite bearing brown breccia of the Udachnaya pipe.Vladykin, N.V., Deep Seated Magmatism: its sources and plumes, pp. 164-186.RussiaMetasomatism
DS201012-0550
2010
Vladykin, A.M.Oktaybrskii, N.V., Vladykin, A.M., Lennikov, A.A., Vrzhosek, T.A., Yasnygina, et al.Chemical composition and geochemical characteristics of the Koksharovka alkaline ultrabasic massif with carbonatites.Geochimica et Cosmochimica Acta, Vol.74, 19, pp. 778-791.Asia, RussiaCarbonatite
DS1996-1487
1996
Vladykin, N.Vladykin, N.Geochemistry and ore potential of potassium alkaline carbonates of AldanInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 394.Russia, Aldan shieldCarbonatite
DS1996-1488
1996
Vladykin, N.Vladykin, N.Petrology, geochemistry and genesis of Potassium alkaline rocks, Aldan shield.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 394.Russia, Aldan shieldCarbonatite, potassium alkaline
DS201312-0225
2013
Vladykin, N.Doroshkevich, A., Ripp, G., Vladykin, N., Savatenkov, V.Sources of the Late Riphean carbonatite magmatism of northern Transbaikalia.Geochemistry International, Vol. 49, 12, pp. 1195-1207.RussiaCarbonatite
DS201412-0020
2014
Vladykin, N.Ashchepkov, I., Remirs, L., Ntaflos, T., Vladykin, N., Logvinova, A., Travin, A., Yudin, D., Karpenko, K., Makovchuk, I., Palessky, S., Salikhov, R.Evolution of mantle column of pipe Sytykanskaya, Yakutia kimberlite.Goldschmidt Conference 2014, 1p. AbstractRussia, YakutiaDeposit - Sytykanskaya
DS201502-0106
2015
Vladykin, N.Sotnikova, I., Vladykin, N.Genesis of rare metal pegmatites and alkaline fluorite rocks of Burpala Massif, northern Baikal folded zone.Economic Geology Research Institute 2015, Vol. 17,, # 3020, 1p. AbstractRussiaCarbonatite
DS201502-0120
2015
Vladykin, N.Vladykin, N.K-alkaline rocks and lamproites of Tomtor Massif.Economic Geology Research Institute 2015, Vol. 17,, # 2937, 1p. AbstractRussiaLamproite
DS201502-0121
2015
Vladykin, N.Vladykin, N.Maldzhangarsky rare metal carbonatite massif in the NE part of the Anabar shield.Economic Geology Research Institute 2015, Vol. 17,, # 2891, 1p. AbstractRussiaCarbonatite
DS201705-0808
2017
Vladykin, N.Ashchepkov, I., Ntaflos, T., Logvinova, A., Vladykin, N., Ivanov, A., Spetsius, Z., Stegnitsky, Y., Kostrovitsky, S., Salikhov, R., Makovchuk, I., Shmarov, G., Karpenko, M., Downes, H., Madvedev, N.Evolution of the mantle sections beneath the kimberlite pipes example of Yakutia.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 6337 AbstractRussia, YakutiaDeposit - Sytykanskaya, Dalnyaya, Aykhal, Zarya, Komosomolskaya, Zarnitsa, Udachnaya

Abstract: The PTX diagrams for the separate phases in Sytykanskaya (Ashchepkov et al., 2016) Dalnyaya (Ashchepkov et al., 2017), pipes shows that the PK show the relatively simple P-X trends and geotherms and shows more contrast and simple layering. The PK contain most abundant material from the root of the magma generation they are dunitic veins as the magma feeders represented by the megacrysts. New results for the Aykhal, Zarya and Komsomolskaya pipes in Alake field and Zarnitsa and Udachnaya pipes in Daldyn field show that evolution is accompanied by the developing of metasomatites and branching and veining of the wall rock peridotites . In Aykhal pipe in PK the Gar- dunites prevail, the xenoliths from the dark ABK "Rebus" contain Cr-Ti - rich garnets and ilmenites, more abundant compared with the grey carbonited breccia Nearly the same features were found for Yubileinaya pipe. The example of Komsomolskya pipes show that the ABK contain more eclogitic xenolith than PK. The developing of the magma channel shown in satellite Chukukskaya and Structurnaya pipe was followed by the separation of some parts of the magmatic feeders and crystallization of abundant Gar megacrysts near o the walls blocking the peridotites from the magma feeder. This drastically decrease diamond grade of pipes. Such blocking seems to be the common features for the latest breccias. In Zarnitsa pipe, the dark PK and ABK also contain fresh xenoliths but not only dunites but also sheared and metasomatic varieties and eclogites. Most of dark ABK in Yakutia contain the intergrowth of ilmenites with brown Ti- Cpx showing joint evolution trends. The late breccia contains completely altered peridotite xenoliths mainly of dunite- harzburgite type. The comparison of the trace elements of the coexisting minerals in megacryst show that they were derived from the protokimberlites but are not in complete equilibrium as well as other megacrystalline phases. Ilmenites show inflections of the trace element patterns of most Ilmenites but more regular for the Cpx and Garnets revealing the sub parallel patterns elevating LREE with the rising TRE. But commonly these are not continuous sequances because they developed in the pulsing moving systems like beneath Zarnitsa. The minerals from the feeders like dunites also show the inflected or S-type REE patterns. From the earlier to later phases the TRE compositions became more evolved reflecting the evolution of protokimberlites. The wall rocks also often show the interaction with the more evolved melts and sometimes "cut" spectrums due to the dissolution some phases and repeated melting events So we could suggest the joint evolution of the mantle column protokimberlites and megacrysts composition and type of kimberlites with the diamond grade. The mantle lithospheric base captured by the PK. The developing and rising protokimbelrites was followed by the crystallization of the diamonds in the gradient in FO2 zone in wall rocks due to reductions of C -bearing fluids and carbonatites (> 1 QMF) on peridotites ((< -2 -5 QMF). The most intensive reactions are near the graphite - diamond boundary where protokimberlites are breaking and where most framesites are forming.
DS201909-2016
2019
Vladykin, N.Ashchepkov, I., Ivanov, A.S., Kostrovitsky, S.I., Vavilov, M.A., Vladykin, N., Babushkina, S.A., Tychkov, N.S., Medvedev, N.S.Mantle terranes of the Siberian craton: their interaction with plume melts based on thermobarometry and geochemistry of mantle xenocrysts.Solid Earth, Vol. 10, 2, pp. 197-245.Russia, Siberiamelting

Abstract: Variations of the structure and composition of mantle terranes in the terminology of the Siberian craton were studied using database (>60000) EPMA of kimberlite xenocrysts from the pipes of Yakutian kimberlite province (YKP) by a team of investigators from IGM, IGH, IEC and IGBM SB RAS and ALROSA company. The monomineral thermobarometry (Ashchepkov et al., 2010, 2014, 2017) Geochemistry of minerals obtained LA ICP MS was used to determine the protolith, melting degree, Type of the metasomatism . The mantle stratification commonly was formed by 6-7 paleosubduction slabs, separated by pyroxenite, eclogite, and metasomatic horizons and dunite lenses beneath kemberltes . We built mantle sections across the kimberlite field and transects of craton. Within the established tectonic terrains strengthening to thousands km (Gladkochub et al, 2006), the collage of microplates was determined at the mantle level. Under the shields of Anabar and Aldan lower SCLM consist of 3 -4 dunites dunites with Gar-Px-Ilm- Phl nests. Terranes framing protocratons like suture Khapchanskyare are saturated in eclogites and pyroxenites, sometimes dominated probably represent the ascending bodies of igneous eclogites intruding mantle lithosphere (ML). The ubiquitous pyroxenite layer at the level of 3.5-4.5 GPa originated in the early Archaean when melted eclogites stoped stoped subdction. Beneath the Early Archaean granite-greenstone terranes - Tunguskaya, Markhinskaya, Birektinskaya, Shary-Zhalgaiskaya (age to~3.8-3.0 GA) (Gladkochub et al., 2018) the SCLM is less depleted and often metasomatized having flat structures in some subterrains. Daldyn and Magan granulite-orthogneisic terranes have a layered and folded ML seen in N-S sections from Udachnaya to Krasnopresnenskaya less pronounced in latitudinal direction. From Daldyn to Alakit field increases the degree of Phl metasomatism and Cpx alkalinity. The most productive Aykhal and Yubleynaya pipes confined to the dunite core. Within the Magan terrane, the thin-layered SCLM have depleted base horizon. Granite-greenstone Markha terrane contains pelitic eclogites. Central and Northern craton parts show slight inclination of paleoslabs to West. The formation of SCLM in Hadean accompanied by submelting (Perchuk et al., 2018, Gerya, 2014.) had no deep roots. Ultrafine craton nuclei like Anabar shield was framed by steeper slab. During 3.8-3.0 GA craton keel growth in superplume periods (Condie, 2004) when melted eclogites and peridotites acquiring buoyancy of the sinking plate melted. For peridotites, the melting lines calculated from the experimental data (Herzberg, 2004) mainly lie near 5-6 GPA (Ionov et al., 2010; 2015). In classical works all geotherms are conductive (Boyd, 1973), but this is quite rare. The garnet pyroxene geotherms for (Ashchepkov et al., 2017) calculated with most reliable methods (Nimis, Taylor, 2000; McGregor , 1974; Brey Kohler, Nickel Green, 1985; Ashchepkov et al., 2010; 2017) give are sub-adiabatic and are formed during the melt percolation superplume vent often in presence of volatiles (Wyllie, Ryabchikov, 2000) and therefore, after superplumes trends P-Fe# of garnet are smoothed and change the tilts.
DS202010-1827
2020
Vladykin, N.Ashchepkov, I., Medvedev, N., Vladykin, N., Ivanov, A., Downes, H.Thermobarometry and geochemistry of mantle xenoliths from Zapolyarnaya pipe, Upper Muna field, Yakutia: implications for mantle layering, interaction with plume melts and diamond grade.Minerals, Vol. 10, 9, 740 10.3390/ min10090755 29p. PdfRussia, Yakutiadeposit - Zapplyarnaya

Abstract: Minerals from mantle xenoliths in the Zapolyarnaya pipe in the Upper Muna field, Russia and from mineral separates from other large diamondiferous kimberlite pipes in this field (Deimos, Novinka and Komsomolskaya-Magnitnaya) were studied with EPMA and LA-ICP-MS. All pipes contain very high proportions of sub-calcic garnets. Zapolyarnaya contains mainly dunitic xenoliths with veinlets of garnets, phlogopites and Fe-rich pyroxenes similar in composition to those from sheared peridotites. PT estimates for the clinopyroxenes trace the convective inflection of the geotherm (40-45 mW•m?2) to 8 GPa, inflected at 6 GPa and overlapping with PT estimates for ilmenites derived from protokimberlites. The Upper Muna mantle lithosphere includes dunite channels from 8 to 2 GPa, which were favorable for melt movement. The primary layering deduced from the fluctuations of CaO in garnets was smoothed by the refertilization events, which formed additional pyroxenes. Clinopyroxenes from the Novinka and Komsomolskaya-Magnitnaya pipes show a more linear geotherm and three branches in the P-Fe# plot from the lithosphere base to the Moho, suggesting several episodes of pervasive melt percolation. Clinopyroxenes from Zapolyarnaya are divided into four groups according to thermobarometry and trace element patterns, which show a stepwise increase of REE and incompatible elements. Lower pressure groups including dunitic garnets have elevated REE with peaks in Rb, Th, Nb, Sr, Zr, and U, suggesting mixing of the parental protokimberlitic melts with partially melted metasomatic veins of ancient subduction origin. At least two stages of melt percolation formed the inclined PT paths: (1) an ancient garnet semi-advective geotherm (35-45 mW•m?2) formed by volatile-rich melts during the major late Archean event of lithosphere growth; and (2) a hotter megacrystic PT path (Cpx-Ilm) formed by feeding systems for kimberlite eruptions (40-45 mW•m?2). Ilmenite PT estimates trace three separate PT trajectories, suggesting a multistage process associated with metasomatism and formation of the Cpx-Phl veinlets in dunites. Heating associated with intrusions of protokimberlite caused reactivation of the mantle metasomatites rich in H2O and alkali metals and possibly favored the growth of large megacrystalline diamonds.
DS202106-0922
2021
Vladykin, N.Ashchepkov, I.,Medvedev, N.,Ivanov, A., Vladykin, N., Ntafos,T.,Downes, H.,Saprykin, A.,Tolstov, A.Vavilov, M., Shmarov, G.Deep mantle roots of the Zarnitsa kimberlite pipe, Siberian craton, Russia: evidence for multistage polybaric interaction with mantle melts.Journal of Asian Earth Sciences, Vol. 213, 104756, 22p.pdfRussia, Siberiadeposit - Zarnitsa

Abstract: Zarnitsa kimberlite pipe in Central Yakutia contains pyrope garnets with Cr2O3 ranging from 9 to 19.3 wt% derived from the asthenospheric mantle. They show mostly S-shaped, inflected rare earth element (REE) patterns for dunitic and harzburgitic, lherzolitic and harzburgitic varieties and all are rich in high field strength elements (HFSE) due to reaction with protokimberlite melts. Lithospheric garnets (<9 wt% Cr2O3) show a similar division into four groups but have more symmetric trace element patterns. Cr-diopsides suggest reactions with hydrous alkaline, protokimberlitic and primary (hydrous) partial melts. Cr-diopsides of metasomatic origin have inclined REE patterns and high LILE, U, Th and Zr concentrations. Four groups in REE of Ti-rich Cr-diopsides, and augites have asymmetric bell-like REE patterns and are HFSE-rich. Mg-ilmenites low in REE were formed within dunite conduits. Ilmenite derived from differentiated melts have inclined REE patterns with LREE ~ 100 × chondrite levels. Thermobarometry for dunites shows a 34 mWm?2 geotherm with a HT branch (>50 mWm?2) at 6-9 GPa, and a stepped HT geotherm with heated pyroxenite lenses at four levels from 6.5 to 3.5 GPa. Parental melts calculated with KDs suggest that augites and high-Cr garnets in the lithosphere base reacted with essentially carbonatitic melts while garnets from lower pressure show subduction peaks in U, Ba and Pb. The roots of the Zarnitsa pipe served to transfer large portions of deep (>9 GPa) protokimberlite melts to the lithosphere. Smaller diamonds were dissolved due to the elevated oxidation state but in peripheral zones large diamonds could grow.
DS201412-0022
2014
Vladykin, N.N.Ashchepkov, I.V., Vladykin, N.N., Ntaflos, T., Kostrovitsky, S.I., Prokopiev, S.A., Downes, H., Smelov, A.P., Agashev, A.M., Logvinova, A.M., Kuligin, S.S., Tychkov, N.S., Salikhov, R.F., Stegnitsky, Yu.B., Alymova, N.V., Vavilov, M.A., Minin, V.A., BabusLayering of the lithospheric mantle beneath the Siberian Craton: modeling using thermobarometry of mantle xenolith and xenocrysts. Tectonophysics, Vol. 634, 5, pp. 55-75.Russia, YakutiaDaldyn, Alakit, Malo-Botuobinsky fields
DS200712-0032
2007
Vladykin, N.P.Ashchepkov, I.V., Pokhilenko, N.P., Logvinova, A.M., Vladykin, N.P., Rotman, Palessky, Alymova, VishnyakovaEvolution of kimberlite magmatic sources beneath Siberia.Plates, Plumes, and Paradigms, 1p. abstract p. A39.RussiaMir
DS200812-0050
2008
Vladykin, N.P.Ashcheperov, I.V., Pokhilenko, N.P., Vladykin, N.P., Logovina, A.M., Nikoleva,I., Palessky, RotmanMelts in mantle columns beneath Siberian kimberlites.Goldschmidt Conference 2008, Abstract p.A35.Russia, SiberiaDeposit - Alkite
DS1985-0703
1985
Vladykin, N.V.Vladykin, N.V.First Occurrence of Lamproites in the UssrDoklady Academy of Sciences AKAD. NAUK SSSR., Vol. 280, No. 3, PP. 718-722.RussiaLamproites
DS1985-0704
1985
Vladykin, N.V.Vladykin, N.V.First Discovery of Lamproites in the Ussr.(russian)Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol.280, No. 3, pp. 718-722RussiaPetrology, Lamproite
DS1989-0921
1989
Vladykin, N.V.Makhotkin, I.L., Arakeliants, M.M., Vladykin, N.V.On the age of lamproites from the Aldanian province. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 306, No. 3, pp. 703-707RussiaLamproite, Geochronology
DS1989-1169
1989
Vladykin, N.V.Panina, L.I., Motorina, I.V., Sharygin, V.V., Vladykin, N.V.Biotitic pyroxenites and melilite-monticellite-olivine rocks of the Malo-Murun alkaline massif of YakutiaSoviet Geology and Geophysics, Vol. 30, No. 12, pp. 40-48RussiaMelilite, Alkaline rocks
DS1990-0975
1990
Vladykin, N.V.Makhotkin, I.L., Arakelyants, M.M., Vladykin, N.V.Age of lamproites of the Aldan provinceDoklady Academy of Sciences USSR, Earth Sci. Section, Vol. 306, No. 3, pp. 163-167RussiaLamproites, Geochronology
DS1990-1521
1990
Vladykin, N.V.Vladykin, N.V.On the genesis of charoite rocksInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 689-690RussiaUltrapotassic, lamproite, Charoite
DS1991-1809
1991
Vladykin, N.V.Vladykin, N.V.Carbonatites of K-alkaline complexes of the Alden, North Pamir and SouthMongoliaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, p. 576Russia, MongoliaCarbonatite, Murun, Darai-Pioz
DS1991-1810
1991
Vladykin, N.V.Vladykin, N.V.Chemical composition and geochemical features of micas from lamproites Of the Aldan shield, USSRProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, p. 577RussiaLamproite, Mineral chemistry
DS1991-1811
1991
Vladykin, N.V.Vladykin, N.V.Geological position, petrology and geochemistry of lamproites (AldanShield, ) SiberiaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, p. 578RussiaLamproite, Petrology
DS1993-1058
1993
Vladykin, N.V.Mitchell, R.H., Vladykin, N.V.Rare earth element bearing tausonite and potassium barium titanates From the Little Murun potassic alkaline complex, Yakutia, Russia.Mineralogical Magazine, Vol. 57, No. 389, December pp. 651-664.Russia, YakutiaAlkaline rocks, Mineralogy, Murun
DS1994-1219
1994
Vladykin, N.V.Mitchell, R.H., Smith, C.B., Vladykin, N.V.Isotopic composition of strontium and neodymium in potassic rocks of the Little Murun complex, Aldan ShieldLithos, Vol. 32, No. 3-4, July pp. 243-248.Russia, Siberia, Aldan Shield, MurunGeochronology, Alkaline -Murun, Little Murun Complex
DS1994-1220
1994
Vladykin, N.V.Mitchell, R.H., Vladykin, N.V.Composition variation of pyroxenes from the Little Murun ultrapotassiccomplex, Aldan Shield, Siberia.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.Russia, SiberiaAlkaline rocks, Little Murun complex
DS1994-1577
1994
Vladykin, N.V.Sharygin, V.V., Vladykin, N.V.Physiochemical conditions of formation of lamproites from the Valgidee Hills Massif (Western Australia).Russian Geology and Geophysics, Vol. 35, No. 4, pp. 52-59.AustraliaLamproites, Valgidee Hills Massif
DS1995-2004
1995
Vladykin, N.V.Vladykin, N.V.Geochemistry and genesis of lamproites of the Aldan shieldProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 660-662.Russia, Aldan shieldGeochemistry, Lamproites
DS1996-0982
1996
Vladykin, N.V.Mitchell, R.H., Vladykin, N.V.Compositional variation of pyroxene and mica from the Little Murumul trapotassic complex, Aldan Shield.Mineralogical Magazine, Vol. 60, No. 403, Dec. pp. 907-925.RussiaMineralogy, Murum Complex
DS1996-1065
1996
Vladykin, N.V.Panina, L.I., Usoltseva, L.M., Vladykin, N.V.Lamproite rocks of the Yakokut Massif and Upper Yakokut depression (Central Alden).Russian Geology and Geophysics, Vol. 37, No. 6, pp. 13-23.Russia, Aldan shieldLamproite, Yakokut
DS1998-1327
1998
Vladykin, N.V.Sharygin, V.V., Panina, L.I., Vladykin, N.V.Silicate melt inclusions in minerals of lamproites from Smoky ButteRussian Geology and Geophysics, Vol. 39, No. 1, pp. 38-54.MontanaLamproites - mineralogy, Deposit - Smoky Butte
DS1998-1548
1998
Vladykin, N.V.Vladykin, N.V., Lelyukh, M.I., Tolstov, A.V.Lamproites of the Anabar region, northern rimming of the SiberianPlatform7th International Kimberlite Conference Abstract, pp. 946-8.Russia, SiberiaLamproites, chemistry, Deposit - Pinabarie
DS2000-0985
2000
Vladykin, N.V.Vladykin, N.V.The Malyi Murun volcano- plutonic complex: an example of differentiated mantle magmas of lamproitic type.Geochemistry International, Vol. 38, No.S1, pp. S73-83.RussiaLamproite, charoite, benstonite, Deposit - Malyi Murun
DS2001-1205
2001
Vladykin, N.V.Vladykin, N.V.The Aldan province of Potassium alkaline rocks and carbonatites: problemsAlkaline Magmatism -problems mantle source, pp. 16-40.Russia, Aldan shieldAlkaline rocks - Carbonatite, Magmatism
DS2002-0071
2002
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Mitchell, R.H., Coopersmith, H., GaraninMantle evolution beneath the Colorado Plateau: interpretation of the study of mineralDoklady Earth Sciences, Vol. 385A, 6, July-August, pp. 721-6.ColoradoTectonics, geochemistry, Deposit - Kelsey Lake
DS2003-0043
2003
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Pokhilenko, N.P., et al.Clinopyroxene geotherms for the mantle columns beneath kimberlite pipes from8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, SiberiaGeothermometry
DS2003-1430
2003
Vladykin, N.V.Vladykin, N.V., Lelyukh, M.I., Tolstov, A.V., Serov, V.P.Petrology of kimberlite lamproite carbonatite rock association, east Prianabar'e (8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussiaBlank
DS200412-0063
2004
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Nikolaeva, I.V., Palessky, Logvinova, Saprykin, Khmelnikova, AnoshinMineralogy and geochemistry of mantle inclusions and mantle column structure of the Yubileinaya kimberlite pipe, Alakit field, YDoklady Earth Sciences, Vol. 395, 4, March-April, pp. 378-384.Russia, YakutiaDiamond - mineralogy, Jubilenya
DS200412-0064
2003
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Pokhilenko, N.P., et al.Clinopyroxene geotherms for the mantle columns beneath kimberlite pipes from Siberian Craton.8 IKC Program, Session 6, POSTER abstractRussia, SiberiaMantle petrology Geothermometry
DS200412-1369
2003
Vladykin, N.V.Morikiyo, T., Kostrovitsky, S.I., Weerakoon, M.W.K., Miyaazaki, T., Vladykin, N.V., Kagami, H., Shuto, K.Sr and Nd isotopic difference between kimberlites and carbonatites from the Siberian Platform.8 IKC Program, Session 7, AbstractRussia, YakutiaKimberlite petrogenesis Geochronology - four zones
DS200412-2062
2003
Vladykin, N.V.Vladykin, N.V., Lelyukh, M.I., Tolstov, A.V., Serov, V.P.Petrology of kimberlite lamproite carbonatite rock association, east Prianabar'e ( Russia).8 IKC Program, Session 7, POSTER abstractRussiaKimberlite petrogenesis
DS200512-0032
2003
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Loginova, A.M., Nikolaeva, Palessky, Khmelnikova, Saprykin, RotmanYubileynaya pipe: from mineralogy to mantle structure and evolution.Plumes and problems of deep sources of alkaline magmatism, pp. 20-38.RussiaGenesis - Jubileynaya
DS200512-0033
2002
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Mitchell, R.H., Coopersmith, H., Garanin, V.G.Geochemical features of the minerals from the heavy concentrate from KL-1 Kelsey lake kimberlite, State Line, Colorado: petrologic reconstruction.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 163-173.United States, ColoradoGeochemistry - Kelsey Lake
DS200512-0034
2004
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Rotman, A.Y., Loginova, A.M., Nikolaeva, L.A., Palessky, V.S., Saprykin, A.I., Anoshin, G.N., Kuchkin, A., Khmelnikova, O.S.Reconstructions of the mantle layering beneath the Alakite kimberlite field: comparative characteristics of the mineral geochemistry and TP sequences.Deep seated magmatism, its sources and their relation to plume processes., pp. 160-177.RussiaGeochemistry - Alakite
DS200512-0035
2003
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Rotman, A.Y., Nikolaeva, Palessky, Anoshin, Khmelnikova, SaprykinMinerals from Zarnitsa pipe kimberlite: the key to enigma of the mantle composition and construction.Plumes and problems of deep sources of alkaline magmatism, pp. 51-64.RussiaMineralogy - Zarnitsa
DS200512-0037
2001
Vladykin, N.V.Ashchepkov,I.V., Vladykin, N.V., Gerasimov, P.A., Saprykin, A.I., Khmelnikova, O.S., Anoshin, G.N.Petrology and mineralogy of disintegrated mantle inclusions of kimberlite like diatremes from the Aldan Shield ( Chompolo field): mantle reconstructions.Alkaline Magmatism and the problems of mantle sources, pp. 161-176.RussiaDiatreme
DS200512-0575
2002
Vladykin, N.V.Kovalenko, V.I., Yarmolyuk, V.V., Vladykin, N.V., Kozlovsky, A.M.Processes leading to eclogitization (densification) of subducted and tectonically buried crust.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 23-41.Asia, RussiaMagmatism
DS200512-0622
2004
Vladykin, N.V.Letnikov, F.A., Kostitsyn, Yu.A., Vladykin, N.V., Zayachkovski, A.A., Mishina, E.I.Isotopic characteristics of the Krasnyi Mai ultramafic alkaline rock complex.Doklady Earth Sciences, Vol. 399A, 9, Nov-Dec. pp. 1315-1319.RussiaAlkalic
DS200512-0746
2001
Vladykin, N.V.Morikiyo, T., Miyazaki, T., Kagami, H., Vladykin, N.V., Chernysheva, E.A., Panina, L.I., Podgornych, N.M.Sr Nd C and O isotope characteristics of Siberian carbonatites.Alkaline Magmatism and the problems of mantle sources, pp. 69-84.Russia, SiberiaGeochronology
DS200512-0747
2004
Vladykin, N.V.Morikiyo, T., Weerakoon, M.W.K., Miyazaki, T., Vladykin, N.V., Kostrovitsky, S.L., Kagami, H., Shuto, K.Difference in Sr and Nd isotopic character of carbonatites and kimberlites from Siberia.Deep seated magmatism, its sources and their relation to plume processes., pp. 112-127.Russia, SiberiaGeochronology
DS200512-0851
2004
Vladykin, N.V.Petrushkin, E.I., Bazarov, L.Sh., Shaygin, V.V., Gordeeva, V.I., Vladykin, N.V.Effect of temperature regime on crystallization of leucite from orendite melt (from experimental data).Russian Geology and Geophysics, Vol. 45, 10, pp. 1159-1166.Mineral chemistry
DS200512-0967
2003
Vladykin, N.V.Sharygin, V.V., Pospelova, L.N., Smirnov, S.Z., Vladykin, N.V.Ni rich sulfide inclusions in early lamproite minerals.Russian Geology and Geophysics, Vol. 44, 9, pp. 817-828.RussiaLamproite - inclusions
DS200512-1146
2001
Vladykin, N.V.Vladykin, N.V.The Aldan Province of K alkaline rocks and carbonatites: problems of magmatism, genesis and deep sources.Alkaline Magmatism and the problems of mantle sources, pp. 16-40.RussiaCarbonatite
DS200512-1147
2002
Vladykin, N.V.Vladykin, N.V., Letyukh, M.I.Lamproite rocks of the eastern Anabar region.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 80-94.RussiaLamproite
DS200512-1148
2004
Vladykin, N.V.Vladykin, N.V., Morikiyo, T., Miyazaki, T.Geochemistry of carbon and oxygen isotopes in carbonatites of Siberia and Mongolia and some geodynamic consequences.Deep seated magmatism, its sources and their relation to plume processes., pp. 96-111.Russia, MongoliaGeochronology, tectonics
DS200512-1149
2003
Vladykin, N.V.Vladykin, N.V., Viladkar, S.G., Miyazaki, T., Ram Mohan, V.Chemical composition of carbonatites of Tamil Nadu massif ( South India) and problem of benstoonite carbonatites.Plumes and problems of deep sources of alkaline magmatism, pp. 130-154.IndiaCarbonatite, geochemistry
DS200612-0045
2005
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Pokhilenko, N.P., Rotman, A.Y., Afansiev, V.P., Logvinova, A.M.Using the monomineral thermobarometry for the reconstruction of the mantle sections.Problems of Sources of Deep Magmatism and Plumes., pp. 210-228.MantleGeothermometry
DS200612-1486
2005
Vladykin, N.V.Vladykin, N.V., Morikiyo, T., Miyazaki, T.Geochemistry of Sr and Nd isotopes in carbonatites of Siberia and Mongolia and some geodynamic consequences.Problems of Sources of deep magmatism and plumes., pp. 19-37.Russia, Siberia, Asia, MongoliaCarbonatite
DS200612-1487
2005
Vladykin, N.V.Vladykin, N.V., Torbeeva, T.S.Lamproites of the Tomtor massif ( eastern Anabar area).Russian Geology and Geophysics, Vol. 46, 10 pp. 1024-1036.RussiaPetrology - lamproites
DS200612-1566
2005
Vladykin, N.V.Yarmolyuk, V.V., Kovalenko, V.I., Salnikova, E.B., Nijiforov, A.V., Lotov, A.B., Vladykin, N.V.Late Riphean rifting and breakup of Laurasia: dat a on geochronological studies of ultramafic alkaline complexes in the southern framing of the Siberian Craton.Doklady Earth Sciences, Vol. 404, 7, pp. 1031-1036.RussiaTectonics, geochronology
DS200712-0573
2006
Vladykin, N.V.Koreshkova, M.Yu., Nikitina, L.P., Vladykin, N.V., Matukov, D.I.U Pb dating of zircon from the lower crustal xenoliths, Udachnaya pipe, Yakutia.Doklady Earth Sciences, Vol. 411, 9, Nov-Dec. pp. 1389-1392.Russia, YakutiaDeposit - Udachnaya
DS200812-0295
2008
Vladykin, N.V.Doroshkevich, A.G., Ripp, G.S., Viladkar, S.G., Vladykin, N.V.The Arshan REE carbonatites, southwestern Transbaiklia, Russia: mineralogy, parageneis, and evolution.Canadian Mineralogist, Vol. 46, 4, August pp.RussiaCarbonatite
DS200812-0746
2008
Vladykin, N.V.Mikhaliov, N.D., Vladykin, N.V., Laptsevich, A.G.Geochemical features of alkali rocks of Paleozoic magmatism of Belarus.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 169-180.Russia, BelarusAlkaline rocks, magmatism
DS200812-1217
2007
Vladykin, N.V.Vladykin, N.V.Formation types of lamproite complex - systematics and chemistry.Vladykin Volume 2007, pp. 20-44.RussiaLamproite
DS200812-1218
2008
Vladykin, N.V.Vladykin, N.V.Formation types of carbonatites geochemistry and genesis.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 14-24.MantleCarbonatite
DS200812-1219
2008
Vladykin, N.V.Vladykin, N.V.Formation types of lamproite complexes - systematization and chemism.9IKC.com, 3p. extended abstractRussia, GlobalLamproite
DS200812-1220
2008
Vladykin, N.V.Vladykin, N.V., Vladkar, S.G., Miyazaki, T., Mohan, V.R.Geochemistry of bentonite and associated carbonatites of Sevathur, Jogipatti and Samalpatti, Tamil Nadu, South India and Murun Massif, Siberia.Journal of the Geological Society of India, Vol. 72, 3, pp. 312-324.India, RussiaCarbonatite
DS200912-0410
2009
Vladykin, N.V.Koreshkova, M.Y., Downes, H., Nikitina, L.P., Vladykin, N.V., Larionov, A.N., Sergeev, S.A.Trace element and age characteristics of zircons in granulite xenoliths from the Udachnaya pipe, Siberia.Precambrian Research, Vol. 168, 3-4, pp. 197-212.Russia, YakutiaGeochronology
DS200912-0520
2009
Vladykin, N.V.Moskalenko, E.Yu., Vladykin, N.V., Oktyabrsky, R.A.Mineral composition and features of geochemistry of the Koksharovsky massif carbonatites, Prymorye Russia.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussiacarbonatite
DS200912-0533
2009
Vladykin, N.V.Nedosekova, I.L., Vladykin, N.V., Pribavkin, S.V., Bayanova, T.B.The Ilmensky Vishnevogorsky miaskite carbonatite complex, the Urals, Russia: origin, ore resource potential, and sources.Geology of Ore Deposits, Vol. 51, 2, pp. 139-161.Russia, UralsCarbonatite
DS200912-0801
2009
Vladykin, N.V.Vladykin, N.V.Geochemistry of isotopes (Sr Nd) and TR of lamproites from the Aldan Shield.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussiaLamproite
DS201012-0822
2009
Vladykin, N.V.Vladykin, N.V.Potassium alkaline lamproite carbonatite complexes: petrology, genesis and ore reserves.Russian Geology and Geophysics, Vol. 50, 12, pp. 1119-1128.RussiaLamproite
DS201012-0823
2010
Vladykin, N.V.Vladykin, N.V., Lepekina, E.A.The age of unusual xenogenic zircons from Yakutian kimberlites.Doklady Earth Sciences, Vol. 429, 2, pp. 1451-1456.Russia, YakutiaGeochronology
DS201112-0035
2011
Vladykin, N.V.Ashchepkov, I.V., Downes, H., Vladykin, N.V., Mitchell, R., Nigmatulina, E., Palessky, S.V.Reconstruction of mantle sequences beneath the Wyoming craton using xenocrysts from Sloan and Kelsey Lake -1 kimberlite pipes, northern Colorado.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 213-233.United States, Colorado PlateauPyrope compositions -geothermobarometry
DS201112-0540
2011
Vladykin, N.V.Koreshkova, M.Yu., Downes, H., Levsky, L.K., Vladykin, N.V.Petrology and geochemistry of granulite xenoliths from Udachnaya and Komosomolskaya kimberlite pipes, Siberia.Journal of Petrology, Vol. 52, 10, pp. 1857-1885.Russia, SiberiaDeposit - Udachnaya, Komosmolskaya
DS201112-0541
2011
Vladykin, N.V.Koreshkova, M.Yu., Downes, H., Levsky, L.K., Vladykin, N.V.Petrology and geochemistry of granulite xenoliths from Udachnaya and Komosomskaya kimberlite pipes, Siberia.Journal of Petrology, Vol. 52, no. 10, pp. 1857-1885.Russia, SiberiaDeposit - Udachnaya, Komosmskaya
DS201112-0542
2011
Vladykin, N.V.Koreshkova, M.Yu., Downes, H., Levsky, L.K., Vladykin, N.V.Petrology and geochemistry of granulite xenoliths from Udachnaya and Komosomolskaya kimberlite pipes, Siberia.Journal of Petrology, Vol. 52, 10, pp. 1857-1885.Russia, SiberiaDeposit - Udachnaya, Komosomolskaya
DS201112-0674
2010
Vladykin, N.V.Mikhailov, N.D., Laptsevich, A.G., Vladykin, N.V.Alkali lamprophyres of the Paleozoic igneous complex of Belarus.Vladykin, N.V., Deep Seated Magmatism: its sources and plumes, pp. 187-199.RussiaLamprophyre
DS201112-0807
2010
Vladykin, N.V.Pokhilenko, L.N., Pokhilenko, N.P., Vladykin, N.V.Garnet orthopyroxenites from the Udachnaya kimberlite pipe ( Yakutia): features of their composition and orogin.Vladykin, N.V., Deep Seated Magmatism: its sources and plumes, pp. 128-144.Russia, YakutiaMineralogy - genesis
DS201112-1094
2011
Vladykin, N.V.Vladykin, N.V.Petrology and composition of rare metal alkaline complexes of the South Gobi, Mongolia.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 46-75.Asia, MongoliaCarbonatite, geochronology
DS201212-0027
2012
Vladykin, N.V.Ashchepkov, Downes, H., Mitchell, R.H., Vladykin, N.V., Palessky, S.V.Mantle lithosphere beneath Wyomng is based on Sloan and Kelsy Lake - 1 kimberlite xenocrysts.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractUnited States, Wyoming, Colorado PlateauDeposit - Sloan, Kelsey Lake
DS201212-0036
2013
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Ntaflos, T., Downes, H., Mitchell, R., Smelov, A.P., Alymova, N.V., Kostrovitsky, S.I., Rotman, A.Ya., Smarov, G.P., Makovchuk, I.V., Stegnitsky, Yu.B., Nigmatulina, E.N., Khmehnikova, O.S.Regularities and mechanism of formation of the mantle lithosphere structure beneath the Siberian Craton in comparison with other cratons.Gondwana Research, Vol. 23, 1, pp. 4-24.Russia, SiberiaKimberlite pipes
DS201212-0037
2012
Vladykin, N.V.Ashchepkov, IV., Nntalfos, T., Pokhilenko, L.N., Ionov, D.A., Vladykin, N.V., Kuligin, S.S., Mityukhin, S.I., Palessky, S.V.Mantle structure beneath Udachnaya pipe reconstructed by fresh mantle xenoliths from brown breccia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Udachnaya
DS201312-0032
2013
Vladykin, N.V.Ashchepkov, I.V., Alymova, N.V., Logvinova, A.M., Vladykin, N.V., Kuligin, S.S., Mityukhin, S.I., Stegnitsky, Y.B., Prokopyev, S.A., Salikhov, R.F., Palessky, V.S., Khmelnikova, O.S.Picroilmenites in Yakutian kimberlites: variations and genetic models.Solid Earth, Vol. 5, pp. 1259-1334.Russia, YakutiaDeposits
DS201312-0034
2012
Vladykin, N.V.Ashchepkov, I.V., Kuligin, S.S., Vavilov, M.A., Vladykin, N.V., Nigmatulina, E.NB., Lkhmelnikova, O.S., Rotman, A.Ya.Characteristic feature of the mantle beneath Kharamai field in comparison with the other regions in Prianabarie.Vladykin, N.V. ed. Deep seated magmatism, its sources and plumes, Russian Academy of Sciences, pp. 226-RussiaGeophysics - seismics
DS201312-0035
2013
Vladykin, N.V.Ashchepkov, I.V., Downes, H., Mitchell, R.H., Vladykin, N.V., Coopersmith, H., Palessky, S.V.Wyoming craton mantle lithosphere: reconstructions based on xenocrysts from Sloan and Kelsey Lake kimberlites.Proceedings of the 10th. International Kimberlite Conference, Vol. 1, Special Issue of the Journal of the Geological Society of India,, Vol. 1, pp. 13-27.United States, Colorado PlateauDeposit - Sloan, Kelsey Lake
DS201312-0045
2013
Vladykin, N.V.Ashchepkov, I.V., Ntaflos, T., Kuligin, S.S., Malygina, E.V., Agashev, A.M., Logvinova, A.M., Mitukhin, S.I., Vladykin, N.V.Deep seated xenoliths from the brown breccia of the Udachnaya pipe, Siberia.Proceedings of the 10th International Kimberlite Conference, Vol. 1, Special issue of the Journal of Geological Society of India, Vol. 1, pp. 59-73.RussiaDeposit - Udachnaya
DS201312-0942
2013
Vladykin, N.V.Vladykin, N.V.Petrology and composition of rare metal alkaline rocks in the South Gobi Desert, Mongolia.Russian Geology and Geophysics, Vol. 54, 4, pp. 416-435.Asia, MongoliaAlkalic
DS201412-0021
2014
Vladykin, N.V.Ashchepkov, I.V., Alymova, N.V., Lognova, A.M., Vladykin, N.V., Kuligin, S.S., Lityukhin, S.I., Downes, H., Stegnitsky, Yu.B., Prokopiev, S.A., Salikhov, R.F., Palessky, V.S., Khmelnikova, O.S.Picroilmenites in Yakutian kimberlites: variations and genetic models.Solid Earth, Vol. 5, pp. 915-938.Russia, YakutiaKimberlite genesis
DS201412-0023
2014
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Ntaflos, T., Yudin, D.S., Karpenko, M.A., Palesskiy, V.S., Khmelnikova, O.S.Deep seated xenoliths and xencrysts from Stykanskaya pipe: evidence for the evolution of the mantle beneath Alakit, Yakutia.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 203-229.RussiaDeposit - Stykanskaya
DS201412-0031
2014
Vladykin, N.V.Baez Presser, J.L., Bitschene, P.R., Vladykin, N.V.Comentarios sobre la gologia, la petrografia y la quimica mineral de Algunas lamproitas de la porcion norte de la cordillera del Ybytyruzu, Paragual oriental.Boletin del Museo Nacional de Historia Narural del Paraguay, Vol. 18, 1, June pp. 24-61.South America, ParaguayMineral chemistry - Lamproites?
DS201412-0199
2014
Vladykin, N.V.Dokuchits, E.Y., Vladykin, N.V.Chemical composition, geochemical features and genesis of charoite and charoite rocks, Murun Complex.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, RussiaCharoite
DS201412-0951
2014
Vladykin, N.V.Vladykin, N.V., Btschene, P., Presser, J.L.B.Lamproitas de la porcion norte de la cordillera del Ybytytuzu, Paraguay oriental: YZU-6.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractSouth America, ParaguayLamproite
DS201412-0952
2014
Vladykin, N.V.Vladykin, N.V., Kotov, A.B., Borisenko, A.S., Yarmolyuk, V.V., Pokhilenko, N.P., Salnikova, E.B., Travin, A.V., Yakovleva, S.Z.Age boundaries of formation of the Tomtor alkaline ultramafic pluton: U Pb and 40 Ar 39 Ar geochronological studies.Doklady Earth Sciences, Vol. 454, 1, pp. 7-11.RussiaGeochronology
DS201412-0953
2014
Vladykin, N.V.Vladykin, N.V., Sotnikov, I.A., Kotov, A.B., Yarmolyuk, V.V., Salnikova, E.B., Yakovleva, S.Z.Structure, age and ore potential of the Burpala rare-metal alkaline Massif, northern Baikal region.Geology of Ore Deposits, Vol. 56, 4, pp. 239-256.RussiaAlkalic
DS201510-1758
2015
Vladykin, N.V.Ashchepkov, I.V., Logvinova, A.M., Reimers, L.F., Ntaflos, T., Spetisus, Z.V., Vladykin, N.V., Downes, H., Yudin, D.S., Travin, A.V., Makovchuk, I.V., Palesskiy, V.S., KhmelNikova, O.S.The Sytykanskaya kimberlite pipe: evidence from deep seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit, Yakutia, Russia.Geoscience Frontiers, Vol. 6, 5, pp. 687-714.Russia, YakutiaDeposit - Sytykanskaya

Abstract: Mantle xenoliths (>150) and concentrates from late autolithic breccia and porphyritic kimberlite from the Sytykanskaya pipe of the Alakit field (Yakutia) were analyzed by EPMA and LAM ICP methods. In P-T-X-f(O2) diagrams minerals from xenoliths show widest variations, the trends P-Fe#-CaO, f(O2) for minerals from porphyric kimberlites are more stepped than for xenocrysts from breccia. Ilmenite PTX points mark moving for protokimberlites from the lithosphere base (7.5 GPa) to pyroxenite lens (5-3.5 GPa) accompanied by Cr increase by AFC and creation of two trends P-Fe#Ol ?10-12% and 13-15%. The Opx-Gar-based mantle geotherm in Alakit field is close to 35 mW/m2 at 65 GPa and 600 °C near Moho was determined. The oxidation state for the megacrystalline ilmenites is lower for the metasomatic associations due to reduction of protokimberlites on peridotites than for uncontaminated varieties at the lithosphere base. Highly inclined linear REE patterns with deep HFSE troughs for the parental melts of clinopyroxene and garnet xenocrysts from breccia were influenced by differentiated protokimberlite. Melts for metasomatic xenoliths reveal less inclined slopes without deep troughs in spider diagrams. Garnets reveal S-shaped REE patterns. The clinopyroxenes from graphite bearing Cr-websterites show inclined and inflected in Gd spectrums with LREE variations due to AFC differentiation. Melts for garnets display less inclined patterns and Ba-Sr troughs but enrichment in Nb-Ta-U. The 40Ar/39Ar ages for micas from the Alakit mantle xenoliths for disseminated phlogopites reveal Proterozoic (1154 Ma) age of metasomatism in early Rodinia mantle. Veined glimmerites with richterite - like amphiboles mark ?1015 Ma plume event in Rodinia mantle. The ?600-550 Ma stage manifests final Rodinia break-up. The last 385 Ma metasomatism is protokimberlite-related.
DS201510-1759
2014
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Ntaflos, T., Logvinova, A.M., Yudin, D.S., Karpenko, M.A., Paleeskiy, V.S., Alymova, N.V., Khmelnikova, O.S.Deep seated xenoliths and xencrysts from Sytykanskaya pipe: evidence for the evolution of the mantle beneath Alakit, Yakutia.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 203-232.Russia, YakutiaDeposit - Sytykanskaya

Abstract: The concentrate from two phases of the kimberlite (breccia and porphyritic kimberlite) and about 130 xenoliths from the Sytykanskaya pipe of the Alakit field (Yakutia) were studied by EPMA and LAM ICP methods. Reconstructions of the PTXfO2 mantle sections were made separately for the two phases. The porphyritic kimberlites and breccia show differences in the minerals although the layering and pressure interval remains the same. For the porphyritic kimberlite the trends P- Fe# - CaO in garnet, fO2 are sub-vertical while the xenocrysts from the breccia show stepped and curved trends possibly due to interaction with fluids. Minerals within xenoliths show the widest variation in all pressure intervals. PT points for the ilmenites which trace the magmatic system show splitting of the magmatic source into two levels at the pyroxenite lens (4GPa) accompanied by peridotite contamination and an increase in Cr in ilmenites. Two groups of metasomatites with Fe#Ol ~ 10-12% and 13-15% were created by the melts derived from protokimberlites and trace the mantle columns from the lithosphere base (Ilm - Gar - Cr diopside) to Moho becoming essentially pyroxenitic (Cr-diopside with Phl). The first Opx-Gar-based mantle geotherm from the Alakit field has been constructed from15 associations and is close to 35 mw/m2 in the lower part of mantle section but deviates to high temperatures in the upper part of the mantle section. The oxidation state for the protokimberlite melts determined from ilmenites is higher than for the other pipes in the Yakutian kimberlite province which probably accounts for the decrease in the diamond grade of this pipe. The geochemistry of the minerals (garnets and clinopyroxenes) from breccias, metasomatic peridotite xenoliths and pyroxenites systematically differ. Xenocrysts from the breccia were produced by the most differentiated melts and enriched protokimberlite or carbonatite; they show highly inclined nearly linear REE patterns and deep troughs of HFSE. Minerals of the metasomatic xenoliths are less inclined with lower La/Cen ratios and without troughs in spider diagrams. The garnets often show S-shaped patterns. Garnets from the Cr websterites show round REE patterns and deep troughs in Ba-Sr but enrichment in Nb-Ta-U. The clinopyroxenes reveal the inclined and inflected on Gd spectrums with variations in LREE due to AFC differentiation. The 40Ar-39Ar ages for micas from the Alakit field reveal three intervals for the metasomatism. The first (1154 Ma) relates to dispersed phlogopites found throughout the mantle column, and probably corresponds to the continental arc stage in the early stage of Rodinia. Veined highly alkaline and Ti-rich veins with richterite ~1015 Ma corresponds to the plume event within the Rodinia mantle. The ~600-550 Ma stage marks the final Rodinia break-up. The last one near 385 Ma is protokimberlite related.
DS201609-1746
2016
Vladykin, N.V.Stoppa, F., Pirajno, F., Schiazza, M., Vladykin, N.V.State of the art: Italian carbonatites and their potential for critical metal deposits.Gondwana Research, Vol. 37, pp. 152-171.Europe, ItalyRare Earths

Abstract: This paper is an updated overview, including many new data, of what is known about Italian alkaline-carbonatite complexes, plus a new description of a carbothermal residua-related district, and its potential for mineral deposits. The Italian carbonatite occurrences can be divided into two belts. The first is a 350 km long and 75 km wide belt along the Apennines mountain range mainly with primary extrusive carbonatites generally from monogenic volcanoes and from the Vulture volcanic complex; the second belt is 60 km long and 20 km wide in the Northern Latium region in which carbothermal residua carbonatites and fluorite mineralisation deposited by high-temperature fluids rich in CO2, SO2 and fluorine are occurring in caldera volcanoes. Several of the raw materials, such as Light Rare Earth Elements, vanadium, niobium, zirconium, fluorite and phosphate are identified as critical as well as other commodities, occur in Italian carbonatites and alkaline rocks. At the Pianciano quarry (Bracciano) fluorite-rich ore (fluor-ore = fluorite in a mineralised gangue) is actually exploited as flux for cement, but Rare Earth Elements (+ V) could be a notable by-product (300,000 metric tonnes, equivalent to 4.2% of European resources). Pyrochlore, monazite, apatite, and britholite bearing subvolcanic rocks in ejecta from the Vulture volcano are of a near-economic grade, but their geological constraints are not known. A conceptual framework of combined geological and geochemical data improves the general understanding of this regional magmatic system, aimed at laying the foundations of a future geological model disclosing unrecognised potential exploration targets. However, this paper is not intended for direct use by the exploration industry; rather it is principally aimed at mineralogists and petrologists who could develop strategies for the identification of unexposed or unrecognised deposits.
DS201611-2146
2016
Vladykin, N.V.Vladykin, N.V., Alymova, N.V., Perfilev, V.V.Geochemical features of rare metal granites of the Zashikhinsky Massif, East Sayan. ( tantalum)Petrology, Vol. 24, 5, pp. 512-525.Russia, IrkutskRare earths

Abstract: The paper presents detailed geochemical data on the rocks of the Zashikhinsky Massif and mineralogical-geochemical characteristics of the ores of the eponymous deposit. The rare-metal granites are divided into three facies varieties on the basis of the degree of differentiation and ore potential: early facies represented by microcline-albite granites with arfvedsonite, middle facies represented by leucocratic albite-microcline granites, and late (most ore-bearing) facies represented by quartz-albite granites grading into albitites. Microprobe data were obtained on major minerals accumulating trace elements in the rocks and ores. All facies of the rare-metal granites, including the rocks of the fluorite-rare-metal vein, define single compositional trends in the plots of paired correlations of rock-forming and trace elements. In addition, they also show similar REE patterns and spidergrams. The latter, however, differ in the depth of anomalies of some elements. Obtained geological, petrographic, and geochemical data suggest a magmatic genesis of the rocks of different composition and their derivation from a single magma during its differentiation. On the basis of all characteristics, the Zashikhinskoe deposit is estimated as one of the largest tantalum rare-metal deposits of alkaline-granite type in Russia.
DS201612-2274
2016
Vladykin, N.V.Ashchepkov, I.V., Logvinova, A.M., Ntaflos, T., Vladykin, N.V., Kostrovitsky, S.I., Spetsius, Z., Mityukhin, S.I., Prokopyev, S.A., Medvedev, N.S., Downe, H.Alakit and Daldyn kimberlite fields, Siberia, Russia: two types of mantle sub-terranes beneath central Yakutia?Geoscience Frontiers, in press availableRussia, SiberiaDeposit - Alakit, Daldyn

Abstract: Mineral data from Yakutian kimberlites allow reconstruction of the history of lithospheric mantle. Differences occur in compositions of mantle pyropes and clinopyroxenes from large kimberlite pipes in the Alakit and Daldyn fields. In the Alakit field, Cr-diopsides are alkaline, and Stykanskaya and some other pipes contain more sub-calcic pyropes and dunitic-type diamond inclusions, while in the Daldyn field harzburgitic pyropes are frequent. The eclogitic diamond inclusions in the Alakit field are sharply divided in types and conditions, while in the Daldyn field they show varying compositions and often continuous Pressure-Temperature (P-T) ranges with increasing Fe# with decreasing pressures. In Alakit, Cr-pargasites to richterites were found in all pipes, while in Daldyn, pargasites are rare Dalnyaya and Zarnitsa pipes. Cr-diopsides from the Alakit region show higher levels of light Rare Earth Elements (LREE) and stronger REE-slopes, and enrichment in light Rare Earth Elements (LREE), sometimes Th-U, and small troughs in Nb-Ta-Zr. In the Daldyn field, the High Field Strength Elements HFSE troughs are more common in clinopyroxenes with low REE abundances, while those from sheared and refertilized peridotites have smooth patterns. Garnets from Alakit show HREE minima, but those from Daldyn often have a trough at Y and high U and Pb. PTXfO2 diagrams from both regions show similarities, suggesting similar layering and structures. The degree of metasomatism is often higher for pipes which show dispersion in P-Fe# trends for garnets. In the mantle beneath Udachnaya and Aykhal, pipes show 6-7 linear arrays of P-Fe# in the lower part of the mantle section at 7.5-3.0 GPa, probably reflecting primary subduction horizons. Beneath the Sytykanskaya pipe, there are several horizons with opposite inclinations which reflect metasomatic processes. The high dispersion of the P-Fe# trend indicating widespread metasomatism is associated with decreased diamond grades. Possible explanation of the differences in mineralogy and geochemistry of the mantle sections may relate to their tectonic positions during growth of the lithospheric keel. Enrichment in volatiles and alkalis possibly corresponds to interaction with subduction-related fluids and melts in the craton margins. Incorporation of island arc peridotites from an eroded arc is a possible scenario.
DS201612-2275
2016
Vladykin, N.V.Ashchepkov, I.V., Ntaflos, T., Logvinova, A.M., Spetsius, Z.V., Downe, H., Vladykin, N.V.Monomineral universal clinopyroxene and garnet barometers for peridotitic, eclogitic and basaltic systems.Geoscience Frontiers, in press availableTechnologyMineralogy

Abstract: New versions of the universal Jd-Di exchange clinopyroxene barometer for peridotites, pyroxenites and eclogites, and also garnet barometer for eclogites and peridotites were developed. They were checked using large experimental data sets for eclogitic (?530) and peridotitic systems (>650). The precision of the universal Cpx barometer for peridotites based on Jd-Di exchange is close to Cr-Tschermakite method produced by Nimis and Taylor (2000). Cpx barometer was transformed by the substitution of major multiplier for KD by the equations dependent from Al-Na-Fe. Obtained equation in combination with the thermometer of Nimis and Taylor (2000) allow to reconstruct position of the magma feeder systems of the alkali basaltic magma within the mantle diapirs in modern platforms like in Vitim plateau and other Southern Siberia localities and several localities worldwide showing good agreement of pressure ranges for black and green suites. These equations allow construct PTX diagrams for the kimberlite localities in Siberia and worldwide calculating simultaneously the PT parameters for different groups of mantle rocks. They give very good results for the concentrates from kimberlite lamproites and placers with mantle minerals. They are useful for PT estimates for diamond inclusions. The positions of eclogite groups in mantle sections are similar to those determined with new Gar-Cpx barometer produced by C. Beyer et al. (2015). The Fe rich eclogites commonly trace the boundary between the lower upper parts of subcontinental lithospheric mantle (SCLM) at 3-4 GPa marking pyroxenite eclogites layer. Ca-rich eclogites and especially grospydites in SCLM beneath Precambrian kimberlites occurs near pyroxenite layer but in younger mantle sections they became common in the lower parts. The diamondiferous Mg Cr-less group eclogites referring to the ancient island arc complexes are also common in the middle part of mantle sections and near 5-6 GPa. Commonly eclogites in lower apart of mantle sections are remelted and trace the high temperature convective branch. The Mg- and Fe-rich pyroxenites also show the extending in pressure trends which suggest the anatexic melting under the influence of volatiles or under the interaction with plums.
DS201612-2344
2016
Vladykin, N.V.Vladykin, N.V., Sotnikova, I.A.Petrology, geochemistry and source characteristics of the Burpala alkaline massif, north Baikal.Geoscience Frontiers, in press availableRussiaAlkalic

Abstract: The Burpala alkaline massif contains rocks with more than 50 minerals rich in Zr, Nb, Ti, Th, Be and rare earth elements (REE). The rocks vary in composition from shonkinite, melanocratic syenite, nepheline and alkali syenites to alaskite and alkali granite and contain up to 10% LILE and HSFE, 3.6% of REE and varying amounts of other trace elements (4% Zr, 0.5% Y, 0.5% Nb, 0.5% Th and 0.1% U). Geological and geochemical data suggest that all the rocks in the Burpala massif were derived from alkaline magma enriched in rare earth elements. The extreme products of magma fractionation are REE rich pegmatites, apatite-fluorite bearing rocks and carbonatites. The Sr and Nd isotope data suggest that the source of primary melt is enriched mantle (EM-II). We correlate the massif to mantle plume impact on the active margin of the Siberian continent.
DS201707-1359
2017
Vladykin, N.V.Presser, J.L.B., Vladykin, N.V., Bitschene, P.R., Tondo, M.J., Acevedo, R.D., Alonso, R., Benitez, P.Olivine-lamproite from Ybtyruzu lamproite field, eastern Paraguay. *** In SpaPyroclastic Flow *** Spa, Vol. 7, 1, pp. 1-15.South America, Paraguaylamproite

Abstract: Numerous Mesozoic bodies of lamproite-like intrusions are located NE and E of the city of Villarrica, Guairá Department, in eastern Paraguay. This magmatic field, known as Ybytyruzú Field, lies immediately on the margin of the SW part of Paranapanemá cratonic-block, just of the Asunción rift backs-horst and so related to deep crustal/lithospheric fracture zones.Mostly of observed rocks are weathered, however fresh samples were collected in dykes from Acaty (=Yzu-2), Tacuarita (=Yzu-7); lava/breccias from Mbocayaty (=Yzu-3); and sill from Salto Boni (=Yzu-6). They intrude, both, the sediments (Independencia Group and Misiones Formation) and the tholeiitic basalts of the Paraná Basin. In the present study we have performed petrographic and mineral chemistry data to show that all of the study rocks, from the Ybytyruzú Field, are lamproites (leucite lamproite from Yzu-2/Yzu-3/Yzu-7 and sanidine lamproite from Yzu-6).With respect to Yzu-2, Yzu-3 and Yzu-6, the following analyzes show the lamproite character: -phenocrysts/microphenocrysts of: olivine (mg# (Mg/(Mg+Fe)) 0.80-0.85), Al-poor diopside (Al2O3 0.53-2.09% and TiO2 0.65-1.61%), phlogopite/Al-poor-Ti phlogopite (mg# 0.76-0.85, TiO2 5.8-10.2% and Al2O3 12.7-13.9%), Mg-Ti magnetites and leucite (pseudomorphs). -and matrix phases of: Al-poor diopside (Al2O3 0.39-2.46% and TiO2 0.43-1.55%), Al-poor-Ti phlogopite/biotite (mg# 0.57-0.80, TiO2 5.6-10.2% and Al2O3 8.9-12.8%), Mg-Ti magnetites/Ti-magnetites; sanidine (0-4.0% Fe2O3, 0-2.6% BaO and 0-2.5% Na2O). And as accessory phases, ilmenite (0.2-5.7% MgO and 0.3-6.6% MnO), K and Ti-rich Feeckermanite/richterite (1.32-3.6% K2O and 4.7-9.0% TiO2), K-rich Fe-Mg-Mn amphiboles, apatite and quartz (Yzu-6). And so, Ybytyruzú lamproite-like intrusions authenticates the true lamproitic province in Paraguay. III; INTERNATIONAL, 2000 BRAZIL 2000; 3 1ST INTERNATIONAL GEOLOGICAL CONGRESS; ABSTRACTS VOLUME
DS201712-2686
2017
Vladykin, N.V.Gladkochub, D.P., Donskaya, T.V., Sklyarov, E.V., Kotov, A.B., Vladykin, N.V., Pisarevsky, S.A., Larin, A.M., Salnikova, E.B., Saveleva, V.B., Sharygin, V.V., Starikova, A.E., Tolmacheva, E.V., Velikoslavinsky, S.D., Mazukabzov, A.M., Bazarova, E.P., KovaThe unique Katugin rare metal deposit ( southern Siberia): constraints on age and genesis.Ore Geology Reviews, in press available, 18p.Russia, Siberiadeposit - Katugin

Abstract: We report new geological, mineralogical, geochemical and geochronological data about the Katugin Ta-Nb-Y-Zr (REE) deposit, which is located in the Kalar Ridge of Eastern Siberia (the southern part of the Siberian Craton). All these data support a magmatic origin of the Katugin rare-metal deposit rather than the previously proposed metasomatic fault-related origin. Our research has proved the genetic relation between ores of the Katugin deposit and granites of the Katugin complex. We have studied granites of the eastern segment of the Eastern Katugin massif, including arfvedsonite, aegirine-arfvedsonite and aegirine granites. These granites belong to the peralkaline type. They are characterized by high alkali content (up to 11.8?wt% Na2O?+?K2O), extremely high iron content (FeO?/(FeO??+?MgO)?=?0.96-1.00), very high content of most incompatible elements - Rb, Y, Zr, Hf, Ta, Nb, Th, U, REEs (except for Eu) and F, and low concentrations of CaO, MgO, P2O5, Ba, and Sr. They demonstrate negative and CHUR-close ?Nd(t) values of 0.0…?1.9. We suggest that basaltic magmas of OIB type (possibly with some the crustal contamination) represent a dominant part of the granitic source. Moreover, the fluorine-enriched fluid phases could provide an additional source of the fluorine. We conclude that most of the mineralization of the Katugin ore deposit occurred during the magmatic stage of the alkaline granitic source melt. The results of detailed mineralogical studies suggest three major types of ores in the Katugin deposit: Zr mineralization, Ta-Nb-REE mineralization and aluminum fluoride mineralization. Most of the ore minerals crystallized from the silicate melt during the magmatic stage. The accessory cryolites in granites crystallized from the magmatic silicate melt enriched in fluorine. However, cryolites in large veins and lens-like bodies crystallized in the latest stage from the fluorine enriched melt. The zircons from the ores in the aegirine-arfvedsonite granite have been dated at 2055?±?7?Ma. This age is close to the previously published 2066?±?6?Ma zircon age of the aegirine-arfvedsonite granites, suggesting that the formation of the Katugin rare-metal deposit is genetically related to the formation of peralkaline granites. We conclude that Katugin rare-metal granites are anorogenic. They can be related to a Paleoproterozoic (?2.05?Ga) mantle plume. As there is no evidence of the 2.05?Ga mantle plume in other areas of southern Siberia, we suggest that the Katugin mineralization occurred on the distant allochtonous terrane, which has been accreted to Siberian Craton later.
DS201801-0006
2017
Vladykin, N.V.Borovikov, A.A., Vladykin, N.V., Tretiakova, I.G., Dokuchits, E.Yu.Physicochemical conditions of formation of hydrothermal titanium mineralization on the Murunskiy alkaline massif, western Alden ( Russia).Ore Geology Reviews, in press available, 10p.Russiaalkaline rocks
DS201803-0443
2018
Vladykin, N.V.Doroshkevich< A.G., Prokopyev, I.R., Izokh, A.E., Klemd, R., Ponomarchuk, A.V., Nikolaeva, I.V., Vladykin, N.V.Isotopic and trace element geochemistry of the Seligdar magnesiocarbonatites ( South Yakutia, Russia): insights regarding the mantle evolution beneath the Aldan Stanovoy shield.Journal of Asian Earth Sciences, Vol. 154, pp. 354-368.Russia, Yakutiacarbonatite -Seligdar

Abstract: The Paleoproterozoic Seligdar magnesiocarbonatite intrusion of the Aldan-Stanovoy shield in Russia underwent extensive postmagmatic hydrothermal alteration and metamorphic events. This study comprises new isotopic (Sr, Nd, C and O) data, whole-rock major and trace element compositions and trace element characteristics of the major minerals to gain a better understanding of the source and the formation process of the carbonatites. The Seligdar carbonatites have high concentrations of P2O5 (up to 18?wt%) and low concentrations of Na, K, Sr and Ba. The chondrite-normalized REE patterns of these carbonatites display significant enrichments of LREE relative to HREE with an average La/Ybcn ratio of 95. Hydrothermal and metamorphic overprints changed the trace element characteristics of the carbonatites and their minerals. These alteration processes were responsible for Sr loss and the shifting of the Sr isotopic compositions towards more radiogenic values. The altered carbonatites are further characterized by distinct 18O- and 13C-enrichments compared to the primary igneous carbonatites. The alteration most likely resulted from both the percolation of crustal-derived hydrothermal fluids and subsequent metamorphic processes accompanied by interaction with limestone-derived CO2. The narrow range of negative ?Nd(T) values indicates that the Seligdar carbonatites are dominated by a homogenous enriched mantle source component that was separated from the depleted mantle during the Archean.
DS201805-0953
2018
Vladykin, N.V.Ivanov, A.V., Mukasa, S.B., Kamenetsky, V.S., Ackerman, M., Demonterova, E.I., Pokrovsky, B.G., Vladykin, N.V., Kolesnichenko, M.V., Litasov, K.D., Zedgenizov, D.A.Origin of high-Mg melts by volatile fluxing without significant excess of temperature.Chemical Geology, https://doi.org/ 10.1016/j .chemgeo. 2018.03.11Russiameimechites
DS202007-1124
2020
Vladykin, N.V.Ashchepkov, I.V., Vladykin, N.V., Kalashnyk, H.A., Medvedev, N.S., Saprykin, A.I., Downes, H., Khmelnikova, O.S.Incompatible element enriched mantle lithosphere beneath kimberlitic pipes in Priazovie Ukrainian shield: volatile enriched focused melt flow and connection to mature crust?International Geology Review, in press available 24p. PdfEurope, Ukrainedeposit - Priazovie

Abstract: Major, minor and trace element compositions of mantle xenocrysts from Devonian kimberlite pipes in the Priazovie give an insight into the mantle structure beneath the SE Ukranian Shield and its evolution. Garnets yield low temperature conditions as determined by monomineral thermobarometry. The mantle lithosphere is sharply divided at 4.2 GPa, marked by a high temperature Cpx-Ilm-Phl trend, eclogites and changes in pyrope geochemistry. Seven layers are detected: Ist layer at 2.5-1 GPa is enriched mantle (Fe#Ol ~ 0.11 ? 0.14) with Gar- pyroxenites and Sp peridotites; IInd at 2.5-3.2 GPa - Gar-Sp (Fe#Ol 0.08 ? 0.10) peridotite. IIId at 4.3-3.2 GPa is formed of Archaean- Proterozoic peridotites with Fe#Ol ~0.07 ? 0.095. IVth at 3.2-5 GPa- contains pyroxenitic Gar with higher Ca, eclogites, Chr and Cpx (Fe#Ol ~0.10 ? 0.125); Vth at 5.8 ? 5 GPa is marked by sub-Ca garnets, Cr-rich chromites and Mg-Cr ilmenites; VIth layer at 5.8-6.8 GPa contains Fe-enriched pyropes, almandines and Cr-Mg ilmenites near the lithosphere base; VIIth layer > 6.8 GPa consists of ‘hot’ Fe-rich garnets. Garnets show increasing enrichment in LREE, LILE, Hf, Zr with decreasing pressure. Primitive garnets have round REE patterns; depleted ones have S-type patterns inflected at Nd. Garnets from 6.5 to 3 GPa show increasing La/Ybn, Zr-Hf, LILE. Peridotitic clinopyroxenes have inclined linear trace element patterns rounded from La to Pr with high LILE and HFSE levels. The Fe-rich group (reacted with eclogites) shows bell-shaped irregular patterns with LILE close to the LREE levels. A possible reason for LILE (HFSE and) enrichment of the upper part of the mantle is subduction metasomatsm in Archaean times (with participation of mature continental sediments) activated by plumes at 1.8 Ga and earlier which produced pervasive focused melt flow with remelting of mica-amphibole metasomatites giving continuous REE and LILE enrichment in mantle lithologies from 5.8 to 2.5 GPa.
DS202008-1426
2020
Vladykin, N.V.Nikolenko, A.M., Doroshkevich, A.G., Ponomarchuk, A.V., Redina, A.A., Prokopyev, I.R., Vladykin, N.V., Nikolaeva, I.V.Ar-Ar geochronology and petrogenesis of the Mushgai-Khudag alkaline-carbonatite complex 9 southern Mongolia).Lithos, Vol. 372-372, 105675 15p. PdfAsia, Mongoliacarbonatite

Abstract: The Mushgai-Khudag alkaline?carbonatite complex, located in southern Mongolia within the Central Asian Orogenic Belt (CAOB), comprises a broad range of volcanic and subvolcanic alkaline silicate rocks (melanephelinite-trachyte and shonkinite-alkaline syenite, respectively). Magnetite-apatite rocks, carbonatites, and fluorite mineralization are also manifested in this area. The complex formed between 145 and 133 Ma and is contemporaneous with late Mesozoic alkaline-carbonatite magmatism within the CAOB. Major and trace element characteristics of silicate rocks in the Mushgai-Khudag complex imply that these rocks were formed by the fractional crystallization of alkaline ultramafic parental magma. Magnetite-apatite rocks may be a product of silicate-Ca-Fe-P liquid immiscibility that took place during the alkaline syenite crystallization stage. The Mushgai-Khudag rocks have variable and moderately radiogenic Sr (87Sr/86Sr(i) = 0.70532-0.70614), ?Nd(t) = ?1.23 to 1.25) isotopic compositions. LILE/HFSE values and SrNd isotope compositions indicate that the parental melts of Mushgai-Khudag were derived from a lithospheric mantle source that was affected by a metasomatic agent in the form a mixture of subducted oceanic crust and its sedimentary components. The ?18OSMOW and ?18CPDB values for calcites in carbonatites range from 16.8‰ to 19.2‰ and from ?3.9‰ to 2.0‰, respectively. CO covariations in calcites of the Mushgai-Khudag carbonatites can be explained by the slight host limestone assimilation.
DS202010-1829
2013
Vladykin, N.V.Ashchepkov, I.V., Alymova, N.V., Loginova, A.M., Vladykin, N.V., Kuligin, S.S., Mityukhin, S.I., Stegnitsky, Y.B., Prokopiev, S.A., Salikhov, R.F., Palessky, V.S., Khmelnikova, O.S.Picroilmenites in Yakutian kimberlites: variations and genetic models. Solid Earth Discussions, Vol. 5, pp. 1-75. pdf * note dateRussia, Yakutiapicroilmenites

Abstract: Major and trace element variations in picroilmenites from Late Devonian kimberlite pipes in Siberia reveal similarities within the region in general, but show individual features for ilmenites from different fields and pipes. Empirical ilmenite thermobarometry (Ashchepkov et al., 2010), as well as common methods of mantle thermobarometry and trace element geochemical modeling, shows long compositional trends for the ilmenites. These are a result of complex processes of polybaric fractionation of protokimberlite melts, accompanied by the interaction with mantle wall rocks and dissolution of previous wall rock and metasomatic associations. Evolution of the parental magmas for the picroilmenites was determined for the three distinct phases of kimberlite activity from Yubileynaya and nearby Aprelskaya pipes, showing heating and an increase of Fe# (Fe# = Fe / (Fe + Mg) a.u.) of mantle peridotite minerals from stage to stage and splitting of the magmatic system in the final stages. High-pressure (5.5-7.0 GPa) Cr-bearing Mg-rich ilmenites (group 1) reflect the conditions of high-temperature metasomatic rocks at the base of the mantle lithosphere. Trace element patterns are enriched to 0.1-10/relative to primitive mantle (PM) and have flattened, spoon-like or S- or W-shaped rare earth element (REE) patterns with Pb > 1. These result from melting and crystallization in melt-feeding channels in the base of the lithosphere, where high-temperature dunites, harzburgites and pyroxenites were formed. Cr-poor ilmenite megacrysts (group 2) trace the high-temperature path of protokimberlites developed as result of fractional crystallization and wall rock assimilation during the creation of the feeder systems prior to the main kimberlite eruption. Inflections in ilmenite compositional trends probably reflect the mantle layering and pulsing melt intrusion during melt migration within the channels. Group 2 ilmenites have inclined REE enriched patterns (10-100)/PM with La / Ybn ~ 10-25, similar to those derived from kimberlites, with high-field-strength elements (HFSE) peaks (typical megacrysts). A series of similar patterns results from polybaric Assimilation + fractional crystallization (AFC) crystallization of protokimberlite melts which also precipitated sulfides (Pb < 1) and mixed with partial melts from garnet peridotites. Relatively low-Ti ilmenites with high-Cr content (group 3) probably crystallized in the metasomatic front under the rising protokimberlite source and represent the product of crystallization of segregated partial melts from metasomatic rocks. Cr-rich ilmenites are typical of veins and veinlets in peridotites crystallized from highly contaminated magma intruded into wall rocks in different levels within the mantle columns. Ilmenites which have the highest trace element contents (1000/PM) have REE patterns similar to those of perovskites. Low Cr contents suggest relatively closed system fractionation which occurred from the base of the lithosphere up to the garnet-spinel transition, according to monomineral thermobarometry for Mir and Dachnaya pipes. Restricted trends were detected for ilmenites from Udachnaya and most other pipes from the Daldyn-Alakit fields and other regions (Nakyn, Upper Muna and Prianabarie), where ilmenite trends extend from the base of the lithosphere mainly up to 4.0 GPa. Interaction of the megacryst forming melts with the mantle lithosphere caused heating and HFSE metasomatism prior to kimberlite eruption.
DS202011-2029
2001
Vladykin, N.V.Ashchepkov, I.V., Afanasiev, V.P., Pokhilenko, N.P., Sobolev, N.V., Vladykin, N.V., Saprykin, A.I., Khmelnikova, O.S., Anoshin, G.N.Small note on the composition of Brazilian mantle. *** NOTE DATERevista Brasileira de Geociencas*** ENG, Vol. 31, 4, pp. 653-660. pdfSouth America, Brazilkimberlites

Abstract: Garne ts from couc eru ratc from the vargcm l kimberl ite pipe show a long compos itional range and reveallong lincar tre nds within the lherzolite field in a Cr~Ol - CaO% dia gram (Sobolcv et til. 1974) (lip (0 11% MgO). fon ned by grains of different dimensions with fcw deviations to harzburg itcs . Larger grains (fraction +3) arc higher in CaO with less Cr~01 (to 5.5%). TIle Cr20 1 freq uen cy reduc es in hyperbo lic function for each fraction . IImenites reve;1142-56% Ti0 2l..'Olllpositionai range with linear FeO - MgO correhuions but 3(4) separate groups for A I ~01 suggest different proport ion of co-prccipimted gimlet , probably due to polybn ric Irncnonanon. lncreasing Cr~O l nnd r"t..-Q% conte nt (fractionation uegn:e ) with red ucing TiO~ is in accord with Ar c mod el.. Ganict xenolith fnnnldnin II pipe with large Ga r- Cpxgrains and fine Mica-Curb bearing mat rix refer to 60 kbcr and 35 mv/m2 gcothcrm . 11displays enr iched trace c lement pat ter ns but not completely equilibrated compositions for Ga r anti Cpx. sugges ting low degree me lting of rela tively fertile mantle. St udied uuuc rinlmay s uggcsrmcrasomu tized, relat ively fertile and irre gularly heated mantle bene ath Sombcrn Bra zil as found by (Carvalho & Lccnnrdos 1997).
DS202103-0420
2021
Vladykin, N.V.Vladykin, N.V., Pirajno, F.Types of carbonatites: geochemistry, genesis and mantle sources.Lithos, Vol. 386-387, 105982, 13p. PdfGlobalcarbonatite

Abstract: Three types of carbonatites have been identified based on the analysis of alkaline complexes using geological, petrological, and geochemical data. It has been suggested that for distinguishing carbonatite complexes into these three types, the following criteria should be used: a) the alkalinity type (Na- or K- richer primary magmas) and b) the time when the carbonatite liquid separates from silicate melts in different stages of primary magma differentiation. The first type is genetically related to the kimberlite magmatism and the carbonatite liquid separates from ultramafic magma. The second type is associated with Na-rich alkaline ultramafic rocks and the carbonatite component separates when pyroxenites and ijolites crystallize. The third type is related to K-alkaline complexes and the carbonatite component separates when syenites and granites crystallize. In this article we discuss the geochemical characteristics of all 3 types and outline the difference between them. A model for the formation of carbonatite complexes under the influence of mantle plume processes is given. The geochemistry of C, O, Sr, and Nd isotopes shows that carbonatite complexes, depending on their geotectonic setting (platform surrounding, orogenic areas and rift zones) can originate from three types of mantle sources: depleted mantle, enriched mantle 1 (EM1), and enriched mantle 2 (EM2).
DS202104-0601
2021
Vladykin, N.V.Prokopyev, I.R., Doroshkevich, A.G., Zhumadilova, D.V., Starikova, A.E., Nugumanova, Ya.N., Vladykin, N.V.Petrogenesis of Zr-Nb ( REE) carbonatites from the Arbarastakh complex ( Aldan Shield, Russia): mineralogy and inclusion data.Ore Geology Reviews, Vol. 131, 104042, 15p. Pdf.Russiadeposit - Arbarastakh

Abstract: The Arbarastakh Neoproterozoic ultramafic carbonatite complex is located in the southwestern part of the Siberian Craton (Aldan Shield) and contains ore-bearing Zr-Nb (REE) carbonatites and phoscorites. Carbonatites are mainly represented by calcite and silicocarbonatite varieties. The primary minerals composing the carbonatites are calcite and dolomite, as well as phlogopite, clinopyroxene, fluorapatite, amphibole, fluorite, K-feldspar and feldspathoids. Olivine (forsterite), Ti-magnetite, apatite, phlogopite, calcite, dolomite and the minor spinel group minerals form the primary phoscorites. The ore-bearing Zr-Nb mineral assemblages of the phoscorites and carbonatites include accessory zircon, zirconolite, perovskite, pyrochlore and baddeleyite. The Ba-Sr-REE hydrothermal mineralisation consists of ancylite-(Ce), bastnaesite-(Ce) and burbankite, as well as barite-celestite, strontianite, barytocalcite, and rare Cu-Fe sulphides. The silicocarbonatites and carbonatites formed in multiple stages from a single alkaline Ca-Na-K-silicocarbonatite melt, while the phoscorites are products of differentiation of the carbonatitic melt and were crystallised from an Fe-rich phosphate-carbonate melt at temperatures of more than 720 °C. The silicate-phosphate-carbonate melts were responsible for the Zr-Nb mineralisation of the carbonatites at temperatures of more than 540-575 °C; the hydrothermal REE-bearing mineral assemblages crystallised from saline (60-70 wt%) carbonatitic fluids of Na-Ca-Mg-F-carbonate composition at a minimum temperature range of 350-300 °C. The Ca-Sr-carbonate as well as the Na-hydro-carbonate fluids were responsible for the Ba-Sr-REE mineralisation of the phoscorites at ~500-480 and 450-430 °C.
DS202107-1088
2021
Vladykin, N.V.Ashchepkov, V., Vladykin, N.V., Kalashnyk, H.A., Medvedev, N.S., Saprykin, A.I., Downes, H., Khmelnikova, O.S.Incompatible element-enriched mantle lithosphere beneath kimberlitic pipes in Proazovie, Ukrainian shield: volatile enriched focused melt flow and connection to mature crust?International Geology Review, Vol. 63, 10, pp. 1288-1309.Europe, Ukrainedeposit - Priazovie

Abstract: Major, minor and trace element compositions of mantle xenocrysts from Devonian kimberlite pipes in the Priazovie give an insight into the mantle structure beneath the SE Ukranian Shield and its evolution. Garnets yield low temperature conditions as determined by monomineral thermobarometry. The mantle lithosphere is sharply divided at 4.2 GPa, marked by a high temperature Cpx-Ilm-Phl trend, eclogites and changes in pyrope geochemistry. Seven layers are detected: Ist layer at 2.5-1 GPa is enriched mantle (Fe#Ol ~ 0.11 ? 0.14) with Gar- pyroxenites and Sp peridotites; IInd at 2.5-3.2 GPa - Gar-Sp (Fe#Ol 0.08 ? 0.10) peridotite. IIId at 4.3-3.2 GPa is formed of Archaean- Proterozoic peridotites with Fe#Ol ~0.07 ? 0.095. IVth at 3.2-5 GPa- contains pyroxenitic Gar with higher Ca, eclogites, Chr and Cpx (Fe#Ol ~0.10 ? 0.125); Vth at 5.8 ? 5 GPa is marked by sub-Ca garnets, Cr-rich chromites and Mg-Cr ilmenites; VIth layer at 5.8-6.8 GPa contains Fe-enriched pyropes, almandines and Cr-Mg ilmenites near the lithosphere base; VIIth layer > 6.8 GPa consists of ‘hot’ Fe-rich garnets. Garnets show increasing enrichment in LREE, LILE, Hf, Zr with decreasing pressure. Primitive garnets have round REE patterns; depleted ones have S-type patterns inflected at Nd. Garnets from 6.5 to 3 GPa show increasing La/Ybn, Zr-Hf, LILE. Peridotitic clinopyroxenes have inclined linear trace element patterns rounded from La to Pr with high LILE and HFSE levels. The Fe-rich group (reacted with eclogites) shows bell-shaped irregular patterns with LILE close to the LREE levels. A possible reason for LILE (HFSE and) enrichment of the upper part of the mantle is subduction metasomatsm in Archaean times (with participation of mature continental sediments) activated by plumes at 1.8 Ga and earlier which produced pervasive focused melt flow with remelting of mica-amphibole metasomatites giving continuous REE and LILE enrichment in mantle lithologies from 5.8 to 2.5 GPa.
DS202107-1103
2021
Vladykin, N.V.Ivanov, A.V., Corfu, F., Kamenetsky, V.S., Marfin, A.E., Vladykin, N.V.207Pb-excess in carbonatitic baddeleyite as the result of Pa scavenging from the melt. ( Guli Siberian traps)Geochemical Perspectives Letters, Vol. 18, pp. 11-15. pdfRussia, Siberiacarbonatite

Abstract: For the last two decades, the end of the voluminous phase of eruptions of the Siberian Traps large igneous province has been constrained by a U-Pb date of discordant baddeleyite collected from the Guli carbonatite intrusion with the assumption that the discordance resulted from unsupported 207Pb. In this study we have re-analysed baddeleyite from the same intrusion and found two types of discordance: (1) due to 207Pb-excess, and (2) radiogenic lead loss from high U mineral inclusions. The former implies that baddeleyite is an efficient scavenger of protactinium during crystallisation, leaving the magma depleted in this element. Together with a published high precision U-Pb date of 252.24?±?0.08 Ma for the Arydzhansky Formation, our new date of 250.33?±?0.38 Ma for the Guli carbonatite constrains the total duration of the voluminous eruptions of the Siberian Traps LIP at 1.91?±?0.38 million years. The lower intercept of the (231Pa)/(235U) corrected discordance line yields a date of 129.2?±?65.0 Ma, which points to the widespread Early Cretaceous rifting in East and Central Asia.
DS202109-1474
2020
Vladykin, N.V.Ivanov, A.V., Corfu, F., Kamenetsky, V.S., Marfin, A.E., Vladykin, N.V.207 Pb-excess in carbonatitic baddeleyite as the result of Pa scavenging from the melt.Geochemical Perspectives Letters, Vol. 18, pp. 11-15. pdfRussia, Siberiadeposit - Guli

Abstract: For the last two decades, the end of the voluminous phase of eruptions of the Siberian Traps large igneous province has been constrained by a U-Pb date of discordant baddeleyite collected from the Guli carbonatite intrusion with the assumption that the discordance resulted from unsupported 207Pb. In this study we have re-analysed baddeleyite from the same intrusion and found two types of discordance: (1) due to 207Pb-excess, and (2) radiogenic lead loss from high U mineral inclusions. The former implies that baddeleyite is an efficient scavenger of protactinium during crystallisation, leaving the magma depleted in this element. Together with a published high precision U-Pb date of 252.24?±?0.08 Ma for the Arydzhansky Formation, our new date of 250.33?±?0.38 Ma for the Guli carbonatite constrains the total duration of the voluminous eruptions of the Siberian Traps LIP at 1.91?±?0.38 million years. The lower intercept of the (231Pa)/(235U) corrected discordance line yields a date of 129.2?±?65.0 Ma, which points to the widespread Early Cretaceous rifting in East and Central Asia.
DS202204-0542
2022
Vladykin, N.V.Vladykin, N.V., Ashchepkov, I.V., Sotnikova, I.A., Medvedev, N.S.Lamproites of Kayla pipe and their mantle xenocrysts, SE Aldan shield, Russia: geochemistry and petrology.Jounral of Earth System Science, Vol. 131 81 doi.org/10/1007/s12040-022-01814-3 19p. PdfRussiadeposit - Kayla

Abstract: Origin of abundant alkaline and related lamproite massifs and dykes in Aldan shield have no explanation and the geochemistry of rocks and their xenocrysts is used for the explanation. Bulk-rock geochemistry, mineral chemistry data of the Kayla lamproites of Russia and mineral chemical data (trace and rare elements) of the mantle xenocrysts found in these lamproites was studied using ICP MS and electron microprobe analyses (EPMA). The trace element spectrum of Kayla tuffs and breccias show the similarity with the olivine lamproites and belong to the orogenic type according to Th-U-Nb systematics. Primitive mantle normalized trace element (TRE) spider diagrams show right-leaning patterns with the peaks in large ion lithophile elements Sr, Pb, U, and troughs in Ta, Nb suggesting melting of original peridotites mixed with the ancient EMI (according to Nd, Sr isotopes) source probably belonging to eclogites or lower crust. The age of the emplacement is 132-134 Ma, similar to the Chompolo lamprophyres and many other alkaline Aldan complexes. Thermo-barometric estimation from Cr-diopsides and chromites xenocrysts suggest the origin from the spinel-garnet transition in the lithospheric mantle region. The P-T estimates derived from low-Cr-clinopyroxene xenocrysts, and related to lamproites show a high heat flow of 90 mW/m2 due to interaction with the plume-related magma. The Cr-diopsides and chromites give 45 mW/m2 geotherm similar to regional heat flow. The chondrite normalized rare earth element (REE) pattern for chrome-diopsides is steeper, compared to the low-chrome varieties. Primitive mantle normalized spidergram of Cr-diopsides displays peaks for Sr, U, and Th, and deep troughs of Nd, Nb, Ta. REE. The trace element spider diagrams of both types of xenocrysts show that they were equilibrated with the lamproitic melts and reconstructed parental melts of low-Cr-clinopyroxene coincides with the lamproite spectrums.
DS202112-1919
2021
Vladykin, N.V.. KuliginAshchepkov, I.V., Alymova, N.V., Loginova, A.M., Vladykin, N.V.. Kuligin, S.S., Mityukhin, S.I., Stegnitsky, Y.B., Prokopiev, S.A.Picroilmenites in Yakutian kimberlites: variations and genetic models.Lithos, Vol. 406-407. doi: 10.1016/j.lithos.2021.106499 77p. PdfRussiakimberlite genesis

Abstract: Major and trace element variations in picroilmenites from Late Devonian kimberlite pipes in Siberia reveal similarities within the region in general, but show individual features for ilmenites from different fields and pipes. Empirical ilmenite thermobarometry (Ashchepkov et al., 2010), as well as common methods of mantle thermobarometry and trace element geochemical modeling, shows long compositional trends for the ilmenites. These are a result of complex processes of polybaric fractionation of protokimberlite melts, accompanied by the interaction with mantle wall rocks and dissolution of previous wall rock and metasomatic associations. Evolution of the parental magmas for the picroilmenites was determined for the three distinct phases of kimberlite activity from Yubileynaya and nearby Aprelskaya pipes, showing heating and an increase of Fe# (Fe# = Fe / (Fe + Mg) a.u.) of mantle peridotite minerals from stage to stage and splitting of the magmatic system in the final stages. High-pressure (5.5–7.0 GPa) Cr-bearing Mg-rich ilmenites (group 1) reflect the conditions of high-temperature metasomatic rocks at the base of the mantle lithosphere. Trace element patterns are enriched to 0.1–10/relative to primitive mantle (PM) and have flattened, spoon-like or S- or W-shaped rare earth element (REE) patterns with Pb > 1. These result from melting and crystallization in melt-feeding channels in the base of the lithosphere, where high-temperature dunites, harzburgites and pyroxenites were formed. Cr-poor ilmenite megacrysts (group 2) trace the high-temperature path of protokimberlites developed as result of fractional crystallization and wall rock assimilation during the creation of the feeder systems prior to the main kimberlite eruption. Inflections in ilmenite compositional trends probably reflect the mantle layering and pulsing melt intrusion during melt migration within the channels. Group 2 ilmenites have inclined REE enriched patterns (10–100)/PM with La / Ybn ~ 10–25, similar to those derived from kimberlites, with high-field-strength elements (HFSE) peaks (typical megacrysts). A series of similar patterns results from polybaric Assimilation + fractional crystallization (AFC) crystallization of protokimberlite melts which also precipitated sulfides (Pb < 1) and mixed with partial melts from garnet peridotites. Relatively low-Ti ilmenites with high-Cr content (group 3) probably crystallized in the metasomatic front under the rising protokimberlite source and represent the product of crystallization of segregated partial melts from metasomatic rocks. Cr-rich ilmenites are typical of veins and veinlets in peridotites crystallized from highly contaminated magma intruded into wall rocks in different levels within the mantle columns. Ilmenites which have the highest trace element contents (1000/PM) have REE patterns similar to those of perovskites. Low Cr contents suggest relatively closed system fractionation which occurred from the base of the lithosphere up to the garnet–spinel transition, according to monomineral thermobarometry for Mir and Dachnaya pipes. Restricted trends were detected for ilmenites from Udachnaya and most other pipes from the Daldyn–Alakit fields and other regions (Nakyn, Upper Muna and Prianabarie), where ilmenite trends extend from the base of the lithosphere mainly up to 4.0 GPa. Interaction of the megacryst forming melts with the mantle lithosphere caused heating and HFSE metasomatism prior to kimberlite eruption.
DS200812-1216
2007
Vladykin, N.V.editor.Vladykin, N.V.editor.Alkaline magmatism, its sources and plumes.Vladykin Volume 2014, 2007, 198p.Russia, Global, MantleIndividual papers listed
DS1993-1057
1993
Vladykin, V.Mitchell, R.H., Smith, C.B., Vladykin, V.Isotopic composition of strontium and neodynium in potassic rocks of the Little Murun Complex, Aldan shield, Siberia.Preprint, 13p.Russia, SiberiaGeochronology, Murun Complex
DS2000-0986
2000
Vladykin, V.Vladykin, V., Ivanuch, W.Paragenesis of ultra akaline granites and leucite syenites with carbonatites of southern Gobi, Mongolia.Igc 30th. Brasil, Aug. abstract only 1p.GlobalShonkinites, leucites, Carbonatite, Geochemistry - Bajun Obo
DS2000-0987
2000
Vladykin, V.Vladykin, V., Ivanuch, W.Carbonatite tuffs of Siberia and Mongolia as promising rare metal raw material.Igc 30th. Brasil, Aug. abstract only 1p.Russia, Siberia, MongoliaTuffites - Tomtor Massif
DS200812-0053
2008
VladykonAshchepkov, Pokhilenko, Vladykon, Loginova, Rotman, Afansiev, Kuligin, Malygina, Alymova, Stegnitsky, KhmetnikovaPlume interaction and evolution of the continental mantle lithosphere.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 104-121.MantlePlume
DS202111-1759
2021
Vlasenko, N.S.Britvin, S., Vlasenko, N.S., Aslandukov, A., Aslandova, A., Dubovinsky, L., Gorelova, L.A., Krzhizhanvskaya, M.G., Vereshchagin, O.S., Bocharov, V.N., Shelukina, Y.S., Lozhkin, M.S., Zaitsev, A.N., Nestola, F.Natural cubic perovskite, Ca(Ti,Si,Cr) O 3-delta, a versatile potential host rock-forming and less common elements up to Earth's mantle pressure.American Mineralogist, doi:10.2138/am-2022-8186 in pressMantleperovskite

Abstract: Perovskite, CaTiO3, originally described as a cubic mineral, is known to have a distorted (orthorhombic) crystal structure. We herein report on the discovery of natural cubic perovskite. This was identified in gehlenite rocks occurring in a pyrometamorphic complex of the Hatrurim Formation (the Mottled Zone), in the vicinity of the Dead Sea, Negev Desert, Israel. The mineral is associated with native ?-(Fe,Ni) metal, schreibersite (Fe3P) and Si-rich fluorapatite. The crystals of this perovskite reach 50 ?m in size and contain many micron sized inclusions of melilite glass. The mineral contains significant amounts of Si substituting for Ti (up to 9.6 wt.% SiO2) corresponding to 21 mol.% of the davemaoite component (cubic perovskite-type CaSiO3), in addition to up to 6.6 wt.% Cr2O3. Incorporation of trivalent elements results in the occurrence of oxygen vacancies in the crystal structure; this being the first example of natural oxygen-vacant ABO3 perovskite with the chemical formula Ca(Ti,Si,Cr)O3-? (? ~ 0.1). Stabilization of cubic symmetry (space group Pm?3m) is achieved via the mechanism not reported so far for CaTiO3, namely displacement of an oxygen atom from its ideal structural position (site splitting). The mineral is stable at atmospheric pressure to 1250±50 °C; above this temperature its crystals fuse with the embedded melilite glass, yielding a mixture of titanite and anorthite upon melt solidification. The mineral is stable upon compression to at least 50 GPa. The a lattice parameter exhibits continuous contraction from 3.808(1) Å at atmospheric pressure to 3.551(6) Å at 50 GPa. The second-order truncation of the Birch-Murnaghan equation of state gives the initial volume V0 equal to 55.5(2) Å3 and room temperature isothermal bulk modulus K0 of 153(11) GPa. The discovery of oxygen-deficient single perovskite suggests previously unaccounted ways for incorporation of almost any element into the perovskite framework up to pressures corresponding to those of the Earth’s mantle.
DS2001-0613
2001
VlasovKlishin, V.I., Sher, E.N., Kramaskov, Vlasov, BasheevUnderground mining of kimberlite pipes under alluviaJournal of Mining Science, Vol.37,4,pp. 421-6.RussiaMining
DS201012-0700
2010
Vlasov, I.Shiryaev, A.A., Fisenko, A.V., Vlasov, I., Semjonova, L.Study of impurities in nanodiamonds from meteorites by spectroscopic methods: implications for their formation.International Mineralogical Association meeting August Budapest, abstract p. 798.TechnologyMeteorite
DS201905-1027
2019
Vlasov, I.I.Ekimov, E.A., Kondrin, M.V., Krivobok, V.S., Khomich, A.A., Vlasov, I.I., Khmelnitskiy, R.A.Effect of Si, Ge and Sn dopant elements on structure and photoluminescence of nano- and microdiamonds synthesized from organic compounds.Diamond & Related Materials, Vol. 93, pp. 75-83.Globalluminescence

Abstract: HPHT synthesis of diamonds from hydrocarbons attracts great attention due to the opportunity to obtain luminescent nano- and microcrystals of high structure perfection. Systematic investigation of diamond synthesized from the mixture of hetero-hydrocarbons containing dopant elements Si or Ge (C24H20Si and C24H20Ge) with a pure hydrocarbon - adamantane (C10H16) at 8?GPa was performed. The photoluminescence of SiV? and GeV? centers in produced diamonds was found to be saturated when Si and Ge contents in precursors exceed some threshold values. The presence of SiC or Ge as second phases in diamond samples with saturated luminescence indicates that ultimate concentrations of the dopants were reached in diamond. It is shown that SiC inclusions can be captured by growing crystals and be a source of local stresses up to 2?GPa in diamond matrix. No formation of Ge-related inclusions in diamonds was detected, which makes Ge more promising as a dopant in the synthesis method. Surprisingly, the synthesis of diamonds from the C24H20Sn hetero-hydrocarbon was ineffective for SnV? formation: only fluorescence of N-and Si-related color centers was detected at room temperature. As an example of great potential for the synthesis method, mass synthesis of 50-nm diamonds with GeV? centers was realized at 9.4?GPa. Single GeV? production in individual nanodiamond was demonstrated.
DS1999-0384
1999
Vlasov, V.N.Kurlenya, M.V., Izakson, V.Yu., Vlasov, V.N.Continuous spiral mining of kimberlite deposits by powered complexes in ascending order.Journal of Mining Science, Vol. 35, No. 6, pp. 621-GlobalMineral processing, mining
DS2003-0131
2003
Vlasov, V.N.Boltengagen, I.L., Vlasov, V.N., Klishin, V.I.Calculation of roller-press parameters for kimberlite ore crushingJournal of Mining Science, Vol. 39, 3, pp. 260-271. www.ingenta.com/isis/searchinGlobalBlank
DS200412-0181
2003
Vlasov, V.N.Boltengagen, I.L., Vlasov, V.N., Klishin, V.I.Calculation of roller-press parameters for kimberlite ore crushing.Journal of Mining Science, Vol. 39, 3, pp. 260-271. ingenta.com /isis/searchinTechnologyMining
DS1987-0684
1987
Vlasova, E.V.Skosyreva, M.V., Bagdasarov, Yu.A., Vlasova, E.V., Zhukhlistov, A.P.Typomorphic characteristics of micas of carbonatite deposit of the east European platform, Kursk Magnetic anomalyarea.(Russian)Geochimiya, (Russian), No. 10, pp. 1386-1397RussiaBlank
DS1987-0757
1987
Vlasova, E.V.UKhanov, A.V., Vlasova, E.V., Devirts, A.L., Ustinov, V.I.IR spectra and isotope composition of hydrogen and oxygen in micas From kimberlites of Yakutia.(Russian)Zap. Vses. Mineral. O. Va, (Russian), Vol. 116, No. 3, pp. 334-341MantleGeochronology, Isotope
DS1993-1677
1993
Vlassopoulos, D.Vlassopoulos, D., Rossman, G.R., Haggerty, S.E.Coupled substitution of Hydrogen and minor elements in rutile and the implications of high OH contents in niobium and chromium rich rutile from the upper mantle.American Mineralogist, Vol. 78, No. 11, 12, November-December pp. 1181-1191.South Africa, Tennessee, GeorgiaMantle geochemistry, Infrared absorption spectra, spectrometry
DS2000-0242
2000
Vlastelic, I.Dosso, L., Bourgault, H., Vlastelic, I.Heterogeneity of the sub oceanic depleted mantleIgc 30th. Brasil, Aug. abstract only 1p.MantleTectonics
DS2002-1673
2002
Vlastelic, I.Vlastelic, I., Bougault, H., Dosso, L.Heterogeneous heat production in the Earth's upper mantle: blob melting and MORB composition.Earth and Planetary Science Letters, Vol.199,1-2,pp.157-72., Vol.199,1-2,pp.157-72.MantleMelting
DS2002-1674
2002
Vlastelic, I.Vlastelic, I., Bougault, H., Dosso, L.Heterogeneous heat production in the Earth's upper mantle: blob melting and MORB composition.Earth and Planetary Science Letters, Vol.199,1-2,pp.157-72., Vol.199,1-2,pp.157-72.MantleMelting
DS200612-1488
2006
Vlastelic, I.Vlastelic, I., Lewin, E., Staudacher, T.Th/U and other geochemical evidence for the Reunion plume sampling a less differentiated mantle domain.Earth and Planetary Science Letters, Vol. 248, 1-2, Aug. 15, pp. 364-378.MantleGeochemistry
DS201504-0199
2015
Vlastelic, I.Gannoun, A., Burton, K.W., Barfod, D.N., Schiano, P., Vlastelic, I., Halliday, A.N.Resolving mantle and magmatic processes in basalts from the Cameroon volcanic line using the Re-Os isotopic system.Lithos, Vol. 224-5, pp. 1-12.Africa, CameroonAlkaline rocks, basalts
DS201910-2295
2019
Vlastelic, I.Rizo, H., Abdrault, D., Bennett, N.R., Humayun, M., Brandon, A., Vlastelic, I., Moine, B., Poirier, A., Bouhifd, M.A., Murphy, D.T.182W evidence for core-mantle interaction in the source of mantle plumes.Geochemical Perspectives Letters, Vol. 11, pp. 6-11.Mantlemantle plumes, hotspots

Abstract: Tungsten isotopes are the ideal tracers of core-mantle chemical interaction. Given that W is moderately siderophile, it preferentially partitioned into the Earth’s core during its segregation, leaving the mantle depleted in this element. In contrast, Hf is lithophile, and its short-lived radioactive isotope 182Hf decayed entirely to 182W in the mantle after metal-silicate segregation. Therefore, the 182W isotopic composition of the Earth’s mantle and its core are expected to differ by about 200 ppm. Here, we report new high precision W isotope data for mantle-derived rock samples from the Paleoarchean Pilbara Craton, and the Réunion Island and the Kerguelen Archipelago hotspots. Together with other available data, they reveal a temporal shift in the 182W isotopic composition of the mantle that is best explained by core-mantle chemical interaction. Core-mantle exchange might be facilitated by diffusive isotope exchange at the core-mantle boundary, or the exsolution of W-rich, Si-Mg-Fe oxides from the core into the mantle. Tungsten-182 isotope compositions of mantle-derived magmas are similar from 4.3 to 2.7 Ga and decrease afterwards. This change could be related to the onset of the crystallisation of the inner core or to the initiation of post-Archean deep slab subduction that more efficiently mixed the mantle.
DS2001-0801
2001
VldadykinMorikiyo, Miyazaki, Kagami, Vldadykin, ChernyshevaStrontium, neodymium, Carbon, and Oxygen isotope characteristics of Siberian carbonatites.Alkaline Magmatism -problems mantle source, pp. 69-84.Russia, SiberiaAlkaline rocks, Geochronology
DS2001-0216
2001
Vn Arsdale, R.B.Cox, R.T., Vn Arsdale, R.B., Harris, J.B., Larsen, D.Neotectonics of the southeastern Reelfoot rift zone margin, central United States And implications for regional strainGeology, Vol. 29, No. 5, May, pp. 419-22.Missouri, Mississippi, MidcontinentTectonics, paleoseismology
DS202005-0751
2020
vn Driel, M.Munch, F.D., Khan, A., Tauzin, B., vn Driel, M., Giardini, D.Seismological evidence for thermo-chemical heterogeneity in Earth's continental mantle.Earth and Planetary Science Letters, Vol. 539, 116240 9p. PdfMantlegeophysics - seismics

Abstract: Earth's thermo-chemical structure exerts a fundamental control on mantle convection, plate tectonics, and surface volcanism. There are indications that mantle convection occurs as an intermittent-stage process between layered and whole mantle convection in interaction with a compositional stratification at 660 km depth. However, the presence and possible role of any compositional layering in the mantle remains to be ascertained and understood. By interfacing inversion of a novel global seismic data set with petrologic phase equilibrium calculations, we show that a compositional boundary is not required to explain short- and long-period seismic data sensitive to the upper mantle and transition zone beneath stable continental regions; yet, radial enrichment in basaltic material reproduces part of the complexity present in the data recorded near subduction zones and volcanically active regions. Our findings further indicate that: 1) cratonic regions are characterized by low mantle potential temperatures and significant lateral variability in mantle composition; and 2) chemical equilibration seems more difficult to achieve beneath stable cratonic regions. These findings suggest that the lithologic integrity of the subducted basalt and harzburgite may be better preserved for geologically significant times underneath cratonic regions.
DS1984-0272
1984
Vnukov, S.P.Fedoseev, D.V., Vnukov, S.P., et al.High Temperature Graphitization of Diamond PowdersDoklady Academy of Sciences AKAD. NAUK SSSR., Vol. 279, No. 1, PP. 149-153.RussiaBlank
DS2001-1206
2001
VOA NewsVOA NewsAngola claims no loopholes in diamond systemVoa News, Aug. 5, 3p.AngolaNews item, Conflict diamonds
DS1995-2005
1995
Vocadlo, L.Vocadlo, L., Patel, A., Price, G.D.Molecular dynamics: some recent change developments in classical and quantum mechanical simulation of mineralsMineralogical Magazine, Vol. 59, Dec. pp. 597-605GlobalMineralogy, Geodynamics
DS1996-1142
1996
Vocadlo, L.Price, G.D., Vocadlo, L.Computational mineralogy...quantitative means of determining mineralstructures, properties and processC.r. Academy Of Science Paris, Vol. 323, 11a, pp. 357-371GlobalMineralogy - lattice dynamics, Computers
DS200712-1125
2007
Vocadlo, L.Vocadlo, L.Ab initio calculations of the elasticity of iron and iron alloys at inner core conditions: evidence for a partially melted inner core?Earth and Planetary Science Letters, Vol. 254, 1-2, Feb. 15, pp. 227-232.MantleMelting
DS201312-0580
2013
Vocadlo, L.Martorell, B., Vocadlo, L., Brodholt, J., Wood, I.G.Strong premelting effect in the elastic properties of hcp-Fe under inner core conditions.Science, Vol. 342, 6157, pp. 466-468.MantleCore, melting
DS200512-0381
2004
Vocen, A.Guo, Z., Hertogen, J., Liu, J., Pasteels, P., Vocen, A.Potassic magmatism in western Sichuan and Yunnan Provinces, SE Tibet, China: petrological and geochemical constraints on petrogenesis.Journal of Petrology, Vol. 46, 1-2, pp. 33-78.China, TibetMagmatism
DS2000-0988
2000
Voeten, T.Voeten, T.The terror of Sierra LeoneVanity Fair, Aug. pp. 110-17, 169-173.Sierra LeoneNews item, Conflict diamonds
DS1900-0279
1904
Vogdes, A.W.Vogdes, A.W.A Bibliography Relating to the Geology, Palaeontology and Mineral Resources of California.California State Mining Bureau Bulletin., No. 30, 290P.United States, California, West CoastGeology
DS1998-1549
1998
Vogel, D.C.Vogel, D.C., Vuollo, J.I., James, R.S.Tectonic, stratigraphic and geochemical comparisons between ca 2500-2440 Mamafic igneous events - shield.Precambrian Research, Vol. 92, No. 2, Oct.l, pp. 89-116Canada, FennoscandiaTectonics - shield, Geochemistry
DS1998-1550
1998
Vogel, D.C.Vogel, D.C., Vuollo, J.I., James, R.S.Tectonic, stratigraphic and geochemical comparisons between 2500-2440 Mamafic igneous events ...shieldPrecambrian Research, Vol. 92, No. 2, Oct. 1, pp. 89-116.Canada, FennoScandia, Finland, DenmarkTectonics - shield, Geochemistry
DS1970-0294
1971
Vogel, D.E.Garlick, G.D., Macgregor, I.D., Vogel, D.E.Oxygen Isotope Ratios in Eclogites from KimberlitesScience., Vol. 172, No. 3987, PP. 1025-1027.South AfricaMineralogy
DS1995-1576
1995
Vogel, G.K.Rinaldo, A., Dietrich, W.E., Rigon, R., Vogel, G.K., et al.Geomorphological signatures of varying climateNature, Vol. 374, April 13, pp. 632-635.GlobalGeomorphology, Drainage patterns
DS1995-1577
1995
Vogel, G.K.Rinaldo, A., Dietrich, W.E., Rigon, R., Vogel, G.K., et al.Geomorphological signature of varying climateNature, Vol. 374, April 13, pp. 632-635GlobalGeomorphology, Fluvial channels, drainage density
DS1990-1522
1990
Vogel, K.R.Vogel, K.R., Slingerland, R.L., Van Niekerk, A.Factors controlling the location of gold placers in alluvial fans: anumerical studyGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A319GlobalAlluvial, Placers -gold
DS1993-1678
1993
Vogel, S.Vogel, S.Under the ozone holeEarth, Vol. 2, No. 1, January pp. 30-35GlobalEarth's ozone, Layman's article
DS1994-1866
1994
Vogel, S.Vogel, S.The big rush... superhot rocks in the earth's mantle...toward the coreEarth, Vol. 3, No. 2, March pp. 39-43MantleMantle plumes, hot spots, Core
DS1994-1867
1994
Vogel, S.Vogel, S.The big rush... superhot rocks in the earth's mantle...toward the coreEarth, Vol. 3, No. 2, March pp. 39-43.MantleMantle plumes, hot spots, Core
DS1995-2006
1995
Vogel, S.Vogel, S.Has global warming begun?Earth, December pp. 25-34United StatesClimate, Global warming
DS1989-0433
1989
Vogel, T.A.Flood, T.P., Schuraytz, B.C., Vogel, T.A.Magma mixing due to disruption of a layered magma bodyJournal of Volcanology and Geothermal Research, Vol. 36, No. 4, February pp. 241-256. Database # 17760GlobalLayered intrusion, Magma mixing
DS1993-1679
1993
Vogely, W.A.Vogely, W.A.An economist looks at resource assessmentNonrenewable Resources, Vol. 2, No. 2, Summer pp. 67-68United StatesEconomics, Ore reserves
DS1975-0886
1978
Vogev, G.Vogev, G.Diamonds and CoralUnknown, GlobalKimberlite, Kimberley, Janlib, History
DS2002-0025
2002
Vogfjord, K.Allen, R.M., Nolet, G., Morgan, W.J., Vogfjord, K., Bergsson, B.H., et al.Imaging the mantle beneath Iceland using integrated seismological techniquesJournal of Geophysical Research, Vol. 107, No. 11, Dec. 06, 10.1029/2001JB000595IcelandGeophysics - seismics
DS1996-1046
1996
Vogfjord, K.S.Nyblade, A.A., Vogfjord, K.S., Langston, C.A.P wave velocity of Proterozoic upper mantle beneath central and southernAsia.Journal of Geophysical Research, Vol. 101, No. 5, May 10, pp. 1159-72.AsiaMantle, Proterozoic
DS2002-0473
2002
Vogl, J.Foster, D.A., Mueller, P.A., Heatherington, A., Vogl, J., Meert, J., Lewis, R.Configuration of the 2.0 - 1.6 GA accretionary margin NW of the Wyoming Province:Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 559.WyomingTectonics, Gondwana
DS200512-1150
2004
Vogl, J.J.Vogl, J.J., Foster, D., Mueller, P., Wooden, J.L.Paleoproterozoic suturing of the Wyoming craton and Medicine Hat Block and it's influence on Phanerozoic crustal evolution.Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 217-2, Vol. 36, 5, p. 507.United States, WyomingAccretion, magmatism
DS200712-0321
2006
Vogl, J.J.Foster, D.A., Mueller, P.A.,Mogk, D.W., Wooden, J.L., Vogl, J.J.Proterozoic evolution of the western margin of the Wyoming Craton: implications for the tectonic and magmatic evolution of the northern Rocky Mountains.Canadian Journal of Earth Sciences, Vol. 43, 10, pp. 1601-1619,United States, Wyoming, Colorado PlateauMagmatism
DS201312-0323
2013
Vogt, K.Gorczyk, W., Vogt, K.Tectonics and melting in intra-continental settings.Gondwana Research, in press availableMantleTectonics
DS201412-0954
2014
Vogt, K.Vogt, K., Gerya, T.V.From oceanic plateaus to allochthonous terranes: numerical modelling.Gondwana Research, Vol. 25, pp. 494-508.MantleSubduction
DS1998-1551
1998
Vogt, P.R.Vogt, P.R., Jung, W., Brozena, J.Arctic margin gravity highs remain puzzlingEos, Vol. 79, No. 49, Dec. 8, pp. 601, 605, 6.Northwest Territories, ArcticGeophysics - gravity, Oceanic crust
DS1998-1552
1998
Vogtmann, W.Vogtmann, W.Diamonds in Michigan..The Rockhound's Michigan, Apr. pp. 59-61.MichiganKimberlite, diamonds, History
DS1991-1475
1991
VohraRuoff, A., Luo, H., Vanderbose, C., Vohra, YkGenerating near earth core pressures with Type IIA diamondsApplied Phys. Letters, Vol. 59, np. 2, November 18, pp. 2681-2682MantleDiamond morphology, Experimental petrology
DS1989-0352
1989
Vohra, Y.K.Desgreniers, S., Vohra, Y.K., Ruoff, A.L.Near infrared photoluminescence due to nitrogen platelets in type 1AdiamondsSolid State Commun, Vol. 70, No. 7, May pp. 705-708GlobalDiamond morphology, Luminescence -Optical pro
DS1989-1562
1989
Vohra, Y.K.Vohra, Y.K., Vanderbo.., C.A., Desgreni.., S., Ruoff, A.L.Near-infrared photoluminescence bands in diamond. (Technical note)Phys. Rev. B., Vol. 39, No. 8, March 15, pp. 5464-5467GlobalDiamond morphology
DS1994-1987
1994
Vohra, Y.K.Zhang, S.G., Zvanut, M.E., Vohra, Y.K., Vagarali, S.S.Nitrogen in the isotopically enriched C-12 diamondAppl. Phys. Letters, Vol. 65, No. 23, Dec. 5, pp. 2951-2957.GlobalDiamond morphology, Nitrogen
DS1900-0134
1902
Vohsen, E.Vohsen, E., Schwabe, A.Prospectus of the Gibeon SyndicateBerlin:, 10P.Africa, NamibiaDiamond Prospecting
DS1997-1214
1997
Voicu, G.Voicu, G., Bardouxm M. Voicu, D.Mineralogical norm calculations applied to tropical weathering profilesMineralogical Magazine, Vol. 61, pt.2, pp. 185-196GlobalWeathering, Laterites
DS201808-1795
2018
Voight, A.Voight, A., Morrison, G., Hill, G., Dellas, G., Mangera, R.The application of XRT in the De Beers Group of Companies. PresentationSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., 25 ppts.GlobalMining - XRT
DS1985-0719
1985
Voight, D.S.Welland, M.J., Cambray, F.W., Voight, D.S.Structural and Stratigraphic Fabric of the Ouachita Thrustbelt, Oklahoma and Arkansaw: a Paleozoic Accretionary Complex.Geological Society of America (GSA), Vol. 17, No. 7, P. 746. (abstract.).United States, Gulf Coast, Arkansas, OklahomaGeotectonics
DS201807-1535
2018
Voigt, A.Voigt, A., Morrison, G., Hill, G., Dellas, G., Mangera, R.The application of XRT in the De Beers Group of Companies. Jwaneng, marineSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 173-184.Africa, Botswana, NamibiaXRT sorters
DS201904-0797
2019
Voigt, A.Voigt, A., Morrison, G., Hikll, G., Dellas, G., Mngera, R.The application of XRT in the De Beers Group of Companies. The Southern African Institute of Mining and Metallurgy, Vol. 119, pp. 149-154.Africa, South Africamineral processing - XRT
DS1991-1812
1991
Voigtman, E.Voigtman, E.Computer simulation in spectrometryAnalyt. ChiM., Vol. 246, No. 1, May 15, pp. 9-22. #FP098GlobalSpectrometry -general, Review
DS200712-0267
2007
Voinkov, D.M.Dorijnamjaa, D., Kondratov, L.S., Voinkov, D.M., Amarsaikhan, Ts.Specific gas composition of the absorbed form in impatites of the diamond bearing Mongolian astropipes.Plates, Plumes, and Paradigms, 1p. abstract p. A231.Asia, MongoliaAgit Khangay, Khuree Mandal Tsenkher, Bayan Khuree
DS201709-1980
2011
Voinkov, D.M.Dorjnamjaa, D., Voinkov, D.M., Kondratov, L.S., Selenge, D., Altanshagai, G., Enkhbatar, B.Concerning diamond and gold bearing astropipes of Mongolia.International Journal of Astronomy and Astrophysics, Vol. 1, pp. 98-104.Asia, Mongoliaastropipes, impact craters

Abstract: In this paper we present summation of eighteen year’s investigation of the all gold and diamond-bearing astropipes of Mongolia. Four astropipe structures are exemplified by the Agit Khangay (10 km in diameter, 470 38' N; 960 05' E), Khuree Mandal (D=11 km; 460 28' N; 980 25' E), Bayan Khuree (D=1 km; 440 06' N; 1090 36' E), and Tsenkher (D=7 km; 980 21' N; 430 36' E) astropipes of Mongolia. Detailed geological and gas-geochemical investigation of the astropipe structures show that diamond genesis is an expression of collision of the lithospheric mantle with the explosion process initiated in an impact collapse meteor crater. The term "astropipes" (Dorjnamjaa et al., 2010, 2011) is a neologism and new scientific discovery in Earth science and these structures are unique in certain aspects. The Mongolian astropipes are genuine "meteorite crater" structures but they also contain kimberlite diamonds and gold. Suevite-like rocks from the astropipes contain such minerals, as olivine, coesite, moissanite (0,6 mm), stishovite, coesite, kamacite,tektite, khamaravaevite (mineral of meteorite titanic carbon), graphite-2H, khondrite, picroilmenite, pyrope, phlogopite, khangaite (tektite glass, 1,0-3,0 mm in size), etc. Most panned samples and hand specimens contain fine diamonds with octahedrol habit (0, 2-2,19 mm, 6,4 mg or 0,034-0,1 carat) and gold (0,1-5 g/t). Of special interest is the large amount of the black magnetic balls (0,05-5,0 mm) are characterized by high content of Ti, Fe, Co, Ni, Cu, Mn, Mg, Cd, Ga, Cl, Al, Si, K. Meanwhile, shatter cones (size approx. 1.0 m) which are known from many meteorite craters on the Earth as being typical of impact craters were first described by us Khuree Mandal and Tsenkher astropipe structures. All the described meteorite craters posses reliable topographic, geological, mineralogical, geochemical, and aerospace mapping data, also some geophysical and petrological features (especially shock metamorphism) have been found, all of which indicate that these structures are a proven new type of gold-diamond-bearing impact structure, termed here "astropipes". The essence of the phenomenon is mantle manifestation and plume of a combined nuclear-magma-palingenesis interaction.
DS1998-1553
1998
Voinova, I.P.Voinova, I.P., Prikhodko, V.S.Post accretionary stage in the evolution of ultramafic magmatism inaccretionary prisms: rock types -7th International Kimberlite Conference Abstract, p. 949.Russia, East, Sikhote AlinStructure, Petrogeochemical mafic rocks
DS2000-0989
2000
Voinova, I.P.Voinova, I.P., Prikhodko, V.S.Magmatic rocks in accretionary prisms and their diamond bearing potential ( Central Sikhote Alin).Igc 30th. Brasil, Aug. abstract only 1p.RussiaBasaltoids, xenoliths
DS200612-1087
2005
Voinova, I.P.Petukhova, L.I., Voinova, I.P., Prikhodko, V.S.Pecularities of alkaline basaltoid mineralogy in Central Sikhote Alin terrigeneous volcanogenic siliceous complexes.Problems of Sources of deep magmatism and plumes., pp. 282-RussiaAlkalic
DS1992-1238
1992
Voinova, O.A.Proskuryakov, V.V., Uvad'yev, L.I., Voinova, O.A.Lamproites of the Karelia-Kola regionDoklady Academy of Sciences USSR, Earth Science Section, Vol. 314, No. 1-6, July 1992, pp. 152-156.Russia, Karelia, KolaLamproites, Petrology
DS1900-0457
1906
Voit, F.W.Voit, F.W.Ueber das Vorkommen von Kimberlit in Gangen und Vulkan-embryonen.Zeitschr. F. Prakt. Geol., Vol. 14, PP. 382-384; Vol. 15, PP. 216-219; PP. 365-369 IN 19Africa, South AfricaPetrology, Kimberlite Mines And Deposits
DS1900-0595
1907
Voit, F.W.Voit, F.W.The Origin of Diamonds (1907)Mines AND MIN. (SCRANTON), Vol. 14, No. 21, AUG. 30TH. P. 10.Africa, South AfricaDiamond Genesis
DS1900-0596
1907
Voit, F.W.Voit, F.W.The Origin of Diamonds (1907 #2)South Africa Mines Commerce and Industry, Vol. 5, PT. 1, JULY 27TH. P. 454. ALSO AUGUST 3RD. P. 470. CAfrica, South AfricaDiamond Genesis
DS1900-0597
1907
Voit, F.W.Voit, F.W.The Origin of Diamonds (1907 #1)Jewellers Circular Keystone, Vol. 55, No. 8, SEPT. 25TH. P. 53; No. 20, Dec. 18TH. P. 41.Africa, South AfricaDiamond Genesis
DS1900-0598
1907
Voit, F.W.Voit, F.W.Covered Diamond PipesJohannesburg: Copy of A Letter Sent To G.f. Kunz, AUGUST 16TH.Africa, South AfricaKimberlite Genesis
DS1900-0599
1907
Voit, F.W.Voit, F.W.The Origin of Diamonds (1907)Geological Society of South Africa Transactions, Vol. 10, PP. 75-80. ALSO: Geological Society of South AfricaAfrica, South AfricaDiamond Genesis
DS1900-0600
1907
Voit, F.W.Voit, F.W.Kimberlite Dykes and Pipes #1Geological Society of South Africa Transactions, Vol. 10, PP. 69-74. ALSO: The Mining Journal R. and COM.Africa, South AfricaPetrology, Kimberlite Mines And Deposits
DS1900-0601
1907
Voit, F.W.Voit, F.W.Further Remarks on the Kimberlite Rock and the Origin of Diamonds.Geological Society of South Africa Transactions, Vol. 10, PP. 101-103.Africa, South AfricaPetrology, Kimberlite Mines And Deposits, Diamond Genesis
DS1900-0714
1908
Voit, F.W.Voit, F.W.KimberlitestockeZeitschr. F. Prakt. Geol., Vol. 16, P. 348.Africa, South AfricaGeology, Kimberlite Mines And Deposits
DS1900-0715
1908
Voit, F.W.Voit, F.W.Vorkommen Vof Diamanten in PegmatitZeitschr. F. Prakt. Geol., Vol. 16, P. 347.Africa, South AfricaNon-kimberlitic Source Rocks
DS1900-0716
1908
Voit, F.W.Voit, F.W.Diamanten in Diabasen. #1Zeitschr. F. Prakt. Geol., Vol. 16, PP. 169-170.Africa, South AfricaNon-kimberlitic Source Rocks
DS1900-0717
1908
Voit, F.W.Voit, F.W.Die Sued afrikanischen Diamantlagerstatten. In: Uebersicht Ueber die Nutzbaren Lagerstatten Suedafrikas.Zeitschr. F. Prak. Geol., Vol. 16, PP. 194-210; PP. 215-216.Africa, South AfricaPetrology, Kimberlite Mines And Deposits
DS1900-0718
1908
Voit, F.W.Voit, F.W.Die Sued afrikanischen DiamantlagerstattenDeut. Geol. Ges. Monatsber., Vol. 60, No. 3, PP. 94-107.Africa, South AfricaPetrology, Kimberlite Mines And Deposits
DS1900-0806
1909
Voit, F.W.Voit, F.W.Kimberlite Rock and the Origin of DiamondsEngineering and Mining Journal, Vol. 87, APRIL 17TH. PP. 789-791.Africa, South AfricaDiamond Genesis
DS1910-0109
1910
Voit, F.W.Voit, F.W.Die Diamant felder Bei der ConceptionsbuchtDeut. Kolonialblatt., Vol. 21, No. 8, PP. 326-331.Southwest Africa, NamibiaGeology, Marine Diamond Placers
DS200512-1155
2004
VoitenkoVrublevskii, V.V., Gertner, I.F., Polyakov, Izokh, Krupchatnikov, Travin, VoitenkoAr Ar isotopic age of lamproite dikes of the Chua Complex, Gornyi Altai.Doklady Earth Sciences, Vol. 399A, 9, Nov-Dec. pp. 1252-55.RussiaLamproite
DS200612-1496
2006
Voitenko, N.N.Vrublevskii, V.V., Voitenko, N.N., Romanov, A.P., Polyakov, G.V., Izokh, A.E., Gertner, I.F., Krupchatnikov, V.I.Magma sources of Triassic lamproites of Gornyi Altai and Taimyr: Sr and Nd isotope evidence for plume lithosphere interaction.Doklady Earth Sciences, Vol. 405A 9, pp. 1365-1367.RussiaLamproite
DS1985-0535
1985
Voitkovs, I.B.Podgaets, A.V., Kotelnik, D.D., Voitkovs, I.B., Ilupin, I.P.Genesis and Pecularities of the Transformation of Magnetite from Yakutian Kimberlites. #2Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 282, No. 5, PP. 1238-1242.RussiaBlank
DS1985-0536
1985
Voitkovskii, I.B.Podgaetskii, A.V., Koteinikov, D.D., Voitkovskii, I.B., Ilupin.Genesis and Pecularities of the Transformation of Magnetite from Yakutian Kimberlites. #1Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 282, No. 2, PP. 1238-1242.Russia, YakutiaMineralogy
DS1988-0740
1988
Voitkovskii, Yu.B.Voitkovskii, Yu.B., Kotelnikov, D.D., Podgaetskii, A.V., Ilupin, I.P.Varieties of magnetite from the kimberlites of Yakutia.(Russian)Zap. Vses. Mineral. O-Va, (Russian), Vol. 116, No. 4, pp. 458-465RussiaBlank
DS1986-0843
1986
Voitkovskiy, Y.B.Voitkovskiy, Y.B., Zinchuk, N.N., et al.Study of iron bearing minerals in kimberlites by the Mossbauer-spectroscopy. (Russian)Izv. Akad. Nauk SSSR Ser. Geol., (Russian), No. 3, March pp. 85-99RussiaSpectroscopy
DS1986-0903
1986
Voitkovskiy, Yu.B.Zinchuk, N.N., Kotelnikov, D.D., Podgaetskiy, A.V., Voitkovskiy, Yu.B.Sequence of variation on some iron containing minerals From kimberlites at differemt stage of supergene process.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol. 290, No. 6, pp. 1467-1471RussiaMineralogy
DS1996-1489
1996
Voitselhovskky, Y.I.Voitselhovskky, Y.I.Self -organization in Tinguaite dykes from Khibiny MassifInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 381.RussiaTinguaites
DS1991-1385
1991
Vokert, R.A.Puffer, J.H., Vokert, R.A., Hozik, M.J.Probable late Proterozoic mafic dikes in the New Jersey HighlandsGeological Society of America Abstracts, Vol. 23, No. 1, February p. 118GlobalDikes, Paleomagnetics
DS1970-0151
1970
Vol.Mooney, H.M., Craddock, C.E., Farnham, P.R., Johnson, S.H., Vol.Refraction Seismic Investigations of the Northern Mid-continent Gravity High.Journal of GEOPHYSICAL RESEARCH, Vol. 75, No. 26, PP. 5056-5086.GlobalMid Continent
DS202009-1673
2020
Volante, S.Volante, S., Pouteau, A., Collins, W.J., Blereau, E., Li, Z-X., Smit, M., Evans, N.J., Nordsvan, A.R., Spencer, C.J., McDonald, B.J., Li, J., Gunter, C.Multiple P-T-d-t paths reveal the evolution of the final Nuna assembly in northeast Australia. Georgetown InlierJournal of Metamorphic Geology, Vol. 38, pp. 593-627.Australiageochronology

Abstract: The final assembly of the Mesoproterozoic supercontinent Nuna was marked by the collision of Laurentia and Australia at 1.60 Ga, which is recorded in the Georgetown Inlier of NE Australia. Here, we decipher the metamorphic evolution of this final Nuna collisional event using petrostructural analysis, major and trace element compositions of key minerals, thermodynamic modelling, and multi?method geochronology. The Georgetown Inlier is characterised by deformed and metamorphosed 1.70-1.62 Ga sedimentary and mafic rocks, which were intruded by c. 1.56 Ga old S?type granites. Garnet Lu-Hf and monazite U-Pb isotopic analyses distinguish two major metamorphic events (M1 at c. 1.60 Ga and M2 at c. 1.55 Ga), which allows at least two composite fabrics to
 
 

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