Kaiser Bottom Fish OnlineFree trialNew StuffHow It WorksContact UsTerms of UseHome
Specializing in Canadian Stocks
SearchAdvanced Search
Welcome Guest User   (more...)
Home / Education
Education
 

SDLRC - Scientific Articles all years by Author - T-Th


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.
Searching this page for a specific term or authorIn your Firefox browser click Edit in the menu bar and then Find. In the Find box that shows up at the bottom of the web page enter your search term. Firefox will highlight all occurrences. This is particularly helpful when the author you are seeking was not the lead author by whom the compilation is sorted.
Sending or sharing a referenceThe left column (Posted/Published) has an embedded hyperlink for each reference. In Firefox, if you right click on it, you can obtain the link url for that reference's location within the page, which you can copy and paste into an email or any other document. You can also use the "share this link" option to tweet, facebook etc the link.
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 - T-Th
Posted/
Published
AuthorTitleSourceRegionKeywords
DS1993-1566
1993
T. Hoare and Co.T. Hoare and Co.The mining commentator... diamonds exciting results from Yamba LakeT. Hoare And Co., 2p. November 5.Northwest TerritoriesNews item, Mill City Group
DS1994-1737
1994
T. Hoare and Co.T. Hoare and Co.Diamonds in the Central African RepublicT. Hoare Co. Mining Commentator, February 11, No. 3/94, pp. 1-7.Central African RepublicNews item -stock report, United Reef
DS1994-1738
1994
T. Hoare and Co. R. ChapinT. Hoare and Co. R. ChapinTexas Star Resources...an interesting diamond explorer... with prospects in three areas.T. Hoare And Co., February 5p.Arkansas, Russia, Northwest TerritoriesNews item, Texas Star Resources
DS1982-0592
1982
Tabarovskii, L.A.Tabarovskii, L.A., Itskovich, G.B.Classification Capability and Resolving Power of the Methodof Transients in Searches for Kimberlites.Soviet Geology And Geophysics, Vol. 23, No. 5, PP. 50-58.RussiaKimberlite, Geophysics
DS201705-0881
2017
Tabassum, N.Tabassum, N., Kohn, S., Smith, C., Bulanova, G.The water concentations and OH in corporation mechanism of silicate inclusions in diamonds. What information do they provide?European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 16735 AbstractAustralia, Canada, Russia, IndiaDiamond inclusions
DS1998-0703
1998
TabiguchiJones, A.P., Dobson, D., Milledge, Tabiguchi, LitvinExperiments with low T potassic carbonatitic melts, fluids and diamonds7th International Kimberlite Conference Abstract, pp. 386-8.GlobalCarbonatite, Petrology - experimental
DS1987-0367
1987
Tabit, A.Kornprobst, J., Piboule, M., Tabit, A.Variety of garnet pyroxenites related to orogenic ultramafic bodies-eclogites, ariegites, griquaites or grospydites- a discussion.(in French)Bulletin Societe Geologique France, (in French), Vol. 3, No. 2, pp. 345-351GlobalPetrology
DS1990-0876
1990
Tabit, A.Kornprobst, J., Piboule, M., Roden, M., Tabit, A.Corundum bearing garnet clinopyroxenites at Beni Bousera (Morocco):original plagioclase rich gabbros recrystallized at depth within the mantle?Journal of Petrology, Vol. 31, pt. 3, pp. 717-745MoroccoMantle, Gabbros
DS1990-0877
1990
Tabit, A.Kornprobst, J., Piboule, M., Roden, M., Tabit, A.Corundum-bearing garnet clinopyroxenites at Beni-Bousera (Morocco)-original plagioclase-rich gabbros recrystallized at depth within the mantleJournal of Petrology, Vol. 31. No. 3, June pp. 597-628MoroccoPetrology, Beni-Bousera
DS200612-1542
2006
Tabit, A.Woodland, A.B., Kornporbst, J., Tabit, A.Ferric iron in orogenic lherzolite massifs and controls of oxygen fugacity in the upper mantle.Lithos, Vol. 89, 1-2, pp. 222-241.MantleGeochronology
DS201612-2322
2016
Tabit, A.Mourabit, Z., Tabit, A., Algouti, A., Algouti, A.The Beni Bousera peridotite ( Rif Belt, Morocco): a subsolidus evolution interpretation.Acta Geologica Sinica, Vol. 90, July abstract p. 111.Africa, MoroccoPeridotite
DS2000-0945
2000
Taboada, A.Taboada, A., Rivera, L., Fuenzalida, A., et al.Geodynamics of the northern Andes: subductions and intracontinental deformation (Colombia).Tectonics, Vol. 19, No. 3, Oct. pp. 787-813.ColombiaTectonics, Subduction - not specific to diamonds
DS201112-0858
2011
Tabod, C.T.Reusch, A.M., Nyblade, A.A., Tibi, R., Wiens, D.A., Shore, P.J., Bekoa, A., Tabod, C.T., Mnange, J.M.Mantle transition zone thickness beneath Cameroon: evidence for an upper mantle origin for the Cameroon Volcanic Line.Geophysical Journal International, Vol. 187, 3, pp.1146-1150.Africa, CameroonMantle zone
DS201212-0363
2012
Tabod, C.T.Koch, F.W., Wiens, D.A., Nyblade, A.A., Shore, P.J., Tibi, R., Ateba, B., Tabod, C.T., Nnange, J.M.Upper mantle anisotropy beneath the Cameroon Volcanic Line and Congo Craton from shear wave splitting measurements.Geophysical Journal International, in press availableAfrica, CameroonGeophysics - seismics
DS201911-2569
2019
Tabor, B.E.Tabor, B.E., Downes, H.Textures of mantle peridotite rocks revisited.Lithos, Vol. 348-349. 13p. PdfMantleperidotite

Abstract: Characterisation of textures in mantle peridotites has long been a subjective method, lacking precise definition or quantification. In a continuing effort to quantify textures found in mantle peridotites, we have analysed thin-sections of a wide variety of spinel and garnet peridotite xenoliths from a range of locations, using a grain-section skeleton outline method. Peridotites from ultramafic massifs have also been analysed using the same methodology. The results for all these samples lie on the same linear trend in a plot of grain-section area vs standard deviation as seen in our previous study. This confirms the utility of the quantitative method, which provides observer-independent objective numerical descriptions of textures in peridotites. In addition, two spinel peridotite xenoliths have been disaggregated using an Electric discharge disaggregation technique and were sieved to produce a grain size distribution. SEM imaging has also been used to show that the 3-D shapes of grains of the constituent minerals have concave features. Computed Tomography (CT)-scanning of separated grains and peridotite rock cores has confirmed the concave features of the constituent minerals and their consequent interlocking structures. A ‘perimeter-area’ relation technique has been used to show that the two-dimensional grain-section skeleton outlines clearly display self-similarity (i.e. fractal characteristics). Images of thin-sections were compared with known Euclidian and fractal images; both the thin-section images and the known fractal images yielded fractal dimensions, whereas the Euclidian images did not. The self-similar or fractal nature of textures of mantle peridotite rocks has also been demonstrated by using Box counting, an alternative method for fractal assessment.
DS1980-0120
1980
Tabor, D.Enomoto, Y., Tabor, D.The Frictional Anisotropy of DiamondNature, Vol. 283, Jan. 3, pp. (2p).GlobalDiamond Morphology
DS1991-1685
1991
Tabor, J.R.Tabor, J.R., Hudelston, P.J.Deformation at an Archean subprovince boundary: northern MinnesotaCanadian Journal of Earth Sciences, Vol. 29\8, pp. 292-307.MinnesotaTectonics
DS1991-1686
1991
Tabor, J.R.Tabor, J.R., Hudleston, P.J.Deformation at an Archean subprovince boundary, northern MinnesotaCanadian Journal of Earth Sciences, Vol. 28, No. 2, February pp. 292-307MinnesotaDeformation, Structure
DS1950-0511
1959
Tabunov, S.M.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
DS1960-0193
1961
Tabunov, S.M.Tabunov, S.M., Lopatin, B.G.Kimberlites in the Region of the River LutchakanNiiga., Vol. 125, PP. 135-159.RussiaBlank
DS1970-0362
1971
Tabunov, S.M.Milashev, V.A., Tabunov, S.M., Gorina, M.A., et al.Kimberlite Fields of Northeastern Siberian Platform In: Kimberlite Volcanism and Primary Diamond Content in the Northeast Part of the Siberian PlatformLeningrad: Niiga., PP. 5-42.RussiaBlank
DS1970-0432
1971
Tabunov, S.M.Tabunov, S.M.The Size and Diamond Content of Kimberlite Diatremes. In: Kimberlite Volcanism and Prospects for Primary Diamond Content in the Northeast Part of the Siberian PlatformLeningrad: Niiga., PP. 144-147.RussiaBlank
DS1970-0433
1971
Tabunov, S.M.Tabunov, S.M.The Relation of Kimberlitic Volcanism with Crystal Fractures. In: Kimberlite Volcanism and Prospects for Primary Diamond Content in the Northeast Part of the Siberian PlatformLeningrad: Niiga., PP. 62-64.RussiaBlank
DS2003-0796
2003
Tachel, T.Leost, I., Tachel, T., Brey, G.P., Harris, J.W.An unusual suite of inclusions in diamonds from Namibia8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractNamibiaDiamonds, Diamond - inclusions
DS200412-1117
2003
Tachel, T.Leost, I., Tachel, T., Brey, G.P., Harris, J.W.An unusual suite of inclusions in diamonds from Namibia.8 IKC Program, Session 3, AbstractAfrica, NamibiaDiamonds Diamond - inclusions
DS201912-2776
2019
Tachel, T.de Hoog, J.C.M., Tachel, T., Harris, J.W.Trace element geochemistry of diamond hosted olivine inclusions from the Akwatia mine, West African Craton: implications for diamond paragenesis and geothermobaromtry.Contributions to Mineralogy and Petrology, Vol. 174, 28p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Trace-element concentrations in olivine and coexisting garnets included in diamonds from the Akwatia Mine (Ghana, West African Craton) were measured to show that olivine can provide similar information about equilibration temperature, diamond paragenesis and mantle processes as garnet. Trace-element systematics can be used to distinguish harzburgitic olivines from lherzolite ones: if Ca/Al ratios of olivine are below the mantle lherzolite trend (Ca/Al??300 µg/g Ca or?>?60 µg/g Na are lherzolitic. Conventional geothermobarometry indicates that Akwatia diamonds formed and resided close to a 39 mW/m2 conductive geotherm. A similar value can be derived from Al in olivine geothermometry, with TAl-ol ranging from 1020 to 1325 °C. Ni in garnet temperatures is on average somewhat higher (TNi-grt?=?1115-1335 °C) and the correlation between the two thermometers is weak, which may be not only due to the large uncertainties in the calibrations, but also due to disequilibrium between inclusions from the same diamond. Calcium in olivine should not be used as a geothermobarometer for harzburgitic olivines, and often gives unrealistic P-T estimates for lherzolitic olivine as well. Diamond-hosted olivine inclusions indicate growth in an extremely depleted (low Ti, Ca, Na, high Cr#) environment with no residual clinopyroxene. They are distinct from olivines from mantle xenoliths which show higher, more variable Ti contents and lower Cr#. Hence, most olivine inclusions in Akwatia diamonds escaped the refertilisation processes that have affected most mantle xenoliths. Lherzolitic inclusions are probably the result of refertilisation after undergoing high-degree melting first. Trivalent cations appear to behave differently in harzburgitic diamond-hosted olivine inclusions than lherzolitic inclusions and olivine from mantle xenoliths. Some divalent chromium is predicted to be present in most olivine inclusions, which may explain high concentrations up to 0.16 wt% Cr2O3 observed in some diamond inclusions. Strong heterogeneity of Cr, V and Al in several inclusions may also result in apparent high Cr contents, and is probably due to late-stage processes during exhumation. However, in general, diamond-hosted olivine inclusions have lower Cr and V than expected compared to mantle xenoliths. Reduced Na activity in depleted harzburgites limits the uptake of Cr, V and Sc via Na-M3+ exchange. In contrast, Al partitioning in harzburgites is not significantly reduced compared to lherzolites, presumably due to uptake of Al in olivine by Al-Al exchange.
DS200612-1403
2006
Tachibana, Y.Tachibana, Y., Kaneoka, I., Gaffney, A., Upton, B.Ocean Island basalt like source of kimberlite magmas from West Greenland revealed by high 3He 4He ratios.Geology, Vol. 34, 4, pp. 273-276.Europe, GreenlandMagmatism - kimberlite mineral chemistry
DS1998-1438
1998
Tack, L.Tack, L., Fernandez-Alonso, M.The West Congolian belt: a critical assessment of available time constraints during the Neoproterozoic..Journal of African Earth Sciences, Vol. 27, 1A, p. 193. AbstractGlobalGondwana
DS2001-1146
2001
Tack, L.Tack, L., Wingate, Liegeois, FernandesAlonzo, DeblondEarly Neoproterozoic magmatism ( 1000-910 Ma) of Zadinian and Mayumbian Groups.. onset Rodinia riftingPrecambrian Research, Vol. 110, No. ER1-4, pp. 277-306.East AfricaCraton - Congo, Magmatism
DS2001-1147
2001
Tack, L.Tack, L., Wingate, Ligeois, Fernandez-Alonzo, De BlondEarly Neoproterozoic magmatism 1000-910 Ma of the Zadinia and Mayumbian groups: onset of Rodinia riftingPrecambrian Research, Vol. 110, pp. 277-306.GlobalMagmatism, Craton - Congo
DS201112-0489
2011
Tack, L.Kadima, E., Delvaux, D., Sebagenzi, S.N., Tack, L., Kabeya, S.M.Structure and geological history of the Congo basin: an integrated interpretation of gravity, magnetic and reflection seismic data.Basin Research, in press availableAfricaGeophysics - seismics
DS201112-0490
2011
Tack, L.Kadima, E., Delvaux, D., Sebagenzi, S.N., Tack, L., Kaybeya, S.M.Structure and geological history of the Congo basin: an integrated interpretation of gravity, magnetic and reflection seismic data.Basin Research, Vol. 23, 5, Oct. pp. 499-527.Africa, Democratic Republic of CongoGeophysics - seismics
DS201312-0090
2013
Tack, L.Boulvais, P., Decree, S., Cobert, C., Midende, G., Tack, L., Gardien, V., Demaiffe, D.C and O isotope compositios of the Matongo carbonatite ( Burundi): new insights into alteration and REE mineralization processes.Goldschmidt 2013, AbstractAfrica, BurundiCarbonatite
DS201412-0575
2014
Tack, L.Midende, G., Boulais, P., Tack, L., Melcher, F., Gerdes,A., Dewaele, S., Demaiffe, D., Decree, S.Petrography, geochemistry and U Pb zircon age of the Matongo carbonatite Massif ( Burundi): implication for the Neoproterozoic geodynamic evolution of Central Africa.Journal of African Earth Sciences, Vol. 100, pp. 656-674.Africa, BurundiCarbonatite
DS201502-0078
2014
Tack, L.Midende, G., Boulvais, P., Tack, L., Melcher, F., Gerdes, A., Dewaele, S., Demaiffe, D., Decree, S.Petrography, geochemistry and U-Pb zircon age of the Matongo carbonatite Massif ( Burundi): implication for the Neoproterozoic geodynamic evolution of Central Africa.Journal of African Earth Sciences, Vol. 100, pp. 656-674.Africa, BurundiCarbonatite
DS201511-1830
2015
Tack, L.Decree, S., Boulvais, P., Tack, L., Andre, L., Baele, J-M.Fluorapatite in carbonatite-related phosphate deposits: the case of the Matongo carbonatite. ( Burundi)Mineralium Deposita, in press available 14p.Africa, BurundiCarbonatite

Abstract: The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic system. Magmatic fluorapatite is abundant in the ore and commonly occurs as millimeter-sized aggregates. It is enriched in light rare earth elements (LREE), which is especially apparent in the final generation of magmatic fluorapatite (up to 1.32 wt% LREE2O3). After an episode of metasomatism (fenitization), which led to the formation of K-feldspar and albite, the fluorapatite-rich rocks were partly brecciated. Oxygen and carbon isotope compositions obtained on the calcite forming the breccia matrix (d18O?=?22.1?- and d13C?=?-1.5?‰) are consistent with the involvement of a fluid resulting from the mixing of magmatic-derived fluids with a metamorphic fluid originating from the country rocks. In a subsequent postmagmatic event, the carbonates hosting fluorapatite were dissolved, leading to intense brecciation of the fluorapatite-rich rocks. Secondary carbonate-fluorapatite (less enriched in LREE with 0.07-0.24 wt% LREE2O3 but locally associated with monazite) and coeval siderite constitute the matrix of these breccias. Siderite has d18O values between 25.4 and 27.7?- and very low d13C values (from -12.4 to -9.2?, which are consistent with the contribution of organic-derived low d13C carbon from groundwater. These signatures emphasize supergene alteration. Finally, the remaining voids were filled with a LREE-poor fibrous fluorapatite (0.01 wt% LREE2O3), forming hardened phosphorite, still under supergene conditions. Pyrochlore and vanadiferous magnetite are other minerals accumulated in the eluvial horizons. As a consequence of the supergene processes and fluorapatite accumulation, the phosphate ore, which contains 0.72 to 38.01 wt% P2O5, is also enriched in LREE (LaN/YbN from 47.1 to 83.5; SREE between 165 and 5486 ppm), Nb (up to 656 ppm), and V (up to 1232 ppm). In the case of phosphate exploitation at Matongo, REE could prove to have a subeconomic potential to be exploited as by-products of phosphates.
DS201601-0013
2015
Tack, L.Decree, S., Boulvais, P., Tack, L., Andre, L., Baele, J-M.Fluorapatite in carbonatite related phosphate deposits: the case for the Matongo carbonatite ( Burundi).Mineralogy and Petrology, in press available, 17p.Africa, BurundiCarbonatite

Abstract: The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic system. Magmatic fluorapatite is abundant in the ore and commonly occurs as millimeter-sized aggregates. It is enriched in light rare earth elements (LREE), which is especially apparent in the final generation of magmatic fluorapatite (up to 1.32 wt% LREE2O3). After an episode of metasomatism (fenitization), which led to the formation of K-feldspar and albite, the fluorapatite-rich rocks were partly brecciated. Oxygen and carbon isotope compositions obtained on the calcite forming the breccia matrix (d18O?=?22.1?‰ and d13C?=?-1.5?‰) are consistent with the involvement of a fluid resulting from the mixing of magmatic-derived fluids with a metamorphic fluid originating from the country rocks. In a subsequent postmagmatic event, the carbonates hosting fluorapatite were dissolved, leading to intense brecciation of the fluorapatite-rich rocks. Secondary carbonate-fluorapatite (less enriched in LREE with 0.07-0.24 wt% LREE2O3 but locally associated with monazite) and coeval siderite constitute the matrix of these breccias. Siderite has d18O values between 25.4 and 27.7?‰ and very low d13C values (from -12.4 to -9.2?‰), which are consistent with the contribution of organic-derived low d13C carbon from groundwater. These signatures emphasize supergene alteration. Finally, the remaining voids were filled with a LREE-poor fibrous fluorapatite (0.01 wt% LREE2O3), forming hardened phosphorite, still under supergene conditions. Pyrochlore and vanadiferous magnetite are other minerals accumulated in the eluvial horizons. As a consequence of the supergene processes and fluorapatite accumulation, the phosphate ore, which contains 0.72 to 38.01 wt% P2O5, is also enriched in LREE (LaN/YbN from 47.1 to 83.5; SREE between 165 and 5486 ppm), Nb (up to 656 ppm), and V (up to 1232 ppm). In the case of phosphate exploitation at Matongo, REE could prove to have a subeconomic potential to be exploited as by-products of phosphates.
DS201904-0727
2019
Tack, L.Decree, S., Demaiffe, D., Tack, L., Nimpagaritse, G., De Paepe, P., Bouvais, P., Debaille, V.The Neoproterozoic Upper Ruvubu alkaline plutonic complex ( Burundi) revisited: large scale syntectonic emplacement, magmatic differentiation and late stage circulations of fluids.Precambrian Research, Vol. 325, pp. 150-171.Africa, Burundicarbonatite

Abstract: The Upper Ruvubu Alkaline Plutonic Complex (URAPC) in Burundi consists of three separate intrusions, each with a specific emplacement age and petrological composition. Three main units are recognized: an outer unit with silica-saturated plutonic rocks (from gabbro to granite), an inner unit with silica-undersaturated plutonic rocks (feldspathoidal syenite with subordinate feldspathoidal monzonite and ijolite) and a carbonatitic body in the subsoil, known by drilling. The URAPC is quite large in size (~24?km long and up to 10?km wide). It is considered to have been intruded syntectonically in an overall extensional context, thanks to the kilometric shear zones that accommodated its emplacement. Radiometric ages from literature range from 748 to 705?Ma and point to structurally-controlled magmatic differentiation followed by long-lived circulations of late-stage fluids postdating the emplacement of a part of the undersaturated rocks and the carbonatites. In the north-western part of the outer unit, gabbro likely has been emplaced at a deeper structural level than the granite, which represents a more apical structural level of emplacement. This petrological, geochemical and isotopic (Sr-Nd-Hf) study concentrates on the processes that generated the URAPC: (i) fractional crystallization, evidenced by the chemical evolution trends of the major and trace elements, and by marked P, Ti and Ba anomalies in the trace element patterns; (ii) crustal assimilation/contamination, as shown by the wide range of Nd isotope compositions and the general increase of the Sr isotope ratios with increasing SiO2 contents, and (iii) late-magmatic/hydrothermal alteration inducing an increase of the Sr isotope composition without changing significantly the Nd isotope composition. The isotopic data are consistent with an asthenospheric mantle source, though less depleted than the Depleted Mantle (DM), contaminated by the Subcontinental Lithospheric Mantle (SCLM). The silicate and carbonate magmatic series are cogenetic. The outer unit is clearly more contaminated than the inner unit, whereas the carbonatitic body could have evolved by liquid immiscibility. The URAPC lies within East Africa’s Western Rift Valley, which is marked by 23 alkaline plutonic complexes. Their emplacement has been ascribed to reactivation of Proterozoic lithospheric weakness zones resulting from the breakup of the Neoproterozoic supercontinent Rodinia supercontinent.
DS1997-1136
1997
Tack, R.E.Tack, R.E., Nazarenko, D.RADARSAT sees the world differently12th. International Conference Applied Geologic Remote Sensing, 7pGlobalRemote sensing, RADARSAT
DS200512-0947
2004
Tackley, P.Schubert, G., Masters, G., Olson, P., Tackley, P.Superplumes or plume clusters?Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 147-178.MantlePlume
DS200612-1404
2006
Tackley, P.Tackley, P.Heatng up the hotspot debates. Book review of Plates, plumes, paradigms.. Foulger et al. GSA SP 388.Science, Vol. 313, p. 1240.MantleHotspots
DS200712-0025
2007
Tackley, P.Arcay, D., Gerya, T., Tackley, P.Magma generation and transport subduction zones: numerical simulations of chemical, thermal and mechanical coupling during magma ascent by porous flow.Goldschmidt 2007 abstracts, 1p. abstract p. A32.MantleMagmatism
DS201112-0137
2011
Tackley, P.Cammarano, F., Tackley, P., Boschi, L.Seismic, petrological and geodynamical constraints on thermal and compositional structure of the upper mantle: global thermochemical models.Geophysical Journal International, in press availableMantleGeophysics - seismics
DS201212-0165
2012
Tackley, P.Dobson, D., Ammann, M., Tackley, P.The grain size of the lower mantle.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleConvection
DS1994-1552
1994
Tackley, P.J.Schubert, G., Tackley, P.J.Mantle dynamics: the strong control of the spinel perovskite transition at a depth of 660 KM.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 137-150.MantleGeodynamics, Perovskite transition
DS1998-1439
1998
Tackley, P.J.Tackley, P.J.Self consistent generation of tectonic plates in three dimensional mantleconvection.Earth and Planetary Science Letters, Vol. 157, No. 1-2, Apr. 15, pp. 9-22.MantleGeophysics, Tectonics
DS1998-1463
1998
Tackley, P.J.Thompson, P.F., Tackley, P.J.Generation of megaplumes from the core mantle boundary in a compressible mantle with temperature -dependent...Geophysical Research Letters, Vol. 25, No. 11, June, pp. 1999-2003.MantleBoundary, Plumes
DS1999-0490
1999
Tackley, P.J.Moore, W.B., Schubert, P.J., Tackley, P.J.The role of rheology in lithospheric thinning by mantle plumesGeophysical Research Letters, Vol. 26, No. 8, Apr. 15, pp. 1073-76.MantlePlumes, hotspots, Lithosphere - thinning
DS2000-0946
2000
Tackley, P.J.Tackley, P.J.Mantle convection and plate tectonics: towards an integrated physical and chemical theory.Science, Vol. 288, No. 5473, June 16, pp. 2002-6.MantleTectonics, Geophysics
DS2002-0447
2002
Tackley, P.J.Farnetani, C.G., Legras, B., Tackley, P.J.Mixing and deformations in mantle plumesEarth and Planetary Science Letters, Vol.196, 1-2, Feb.28, pp. 1-15.MantlePLumes - review
DS2002-1574
2002
Tackley, P.J.Tackley, P.J., Xie, S.The thermochemical structure and evolution of Earth's mantle: constraints and numerical models.Philosophical Transactions, Royal Society of London Series A Mathematical, Vol.1800, pp. 2593-2610.MantleGeochemistry - model, geothermometry
DS200412-1396
2004
Tackley, P.J.Nakagawa, T., Tackley, P.J.Effects of thermo-chemical mantle convection on the thermal evolution of the Earth's core.Earth and Planetary Science Letters, Vol. 220, 1-2, March 30, pp. 107-119.MantleGeothermometry, core mantle boundary, convection
DS200412-1397
2004
Tackley, P.J.Nakagawa, T., Tackley, P.J.Thermo-chemical structure in the mantle arising from a three component convective system and implications for geochemistry.Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 125-138.MantleGeothermometry
DS200412-2154
2004
Tackley, P.J.Xie, S., Tackley, P.J.Evolution of helium and argon isotopes in a convecting mantle.Physics of the Earth and Planetary Interiors, Vol. 146, 3-4, pp. 417-439.MantleGeochronology, convection, radiogenic isotopes
DS200512-0424
2005
Tackley, P.J.Hernlund, J.W., Thomas, C., Tackley, P.J.A doubling of the post perovskite phase boundary and structure of the Earth's lowermost mantle.Nature, no. 7035, pp. 882-885.MantlePerovskite
DS200512-0494
2005
Tackley, P.J.Jurine, D., Jaupart, C., Brandeis, G., Tackley, P.J.Penetration of mantle plumes through depleted lithosphere.Journal of Geophysical Research, Vol. 110, B10, B 10104 10.1029/2005 JB003751MantleTectonics
DS200512-0763
2004
Tackley, P.J.Nakagawa, T., Tackley, P.J.Effects of perovskite-post perovskite phase change near core-mantle boundary in compressible mantle convection.Geophysical Research Letters, Vol. 31, 16, L16611 DOI 10.1029/2004 GLO20648MantleConvection
DS200512-0764
2005
Tackley, P.J.Nakagawa, T., Tackley, P.J.Deep mantle heat flow and thermal evolution of the Earth's core in thermochemical multiphase models of mantle convection.Geochemistry, Geophysics, Geosystems: G3, Vol. 6, doi. 10.1029/2005 GC000967MantleCore, mantle boundary, geothermometry
DS200512-1206
2004
Tackley, P.J.Xie, S., Tackley, P.J.Evolution of U-Pb and Sm-Nd systems in numerical modles of mantle convection and plate tectonics.Journal of Geophysical Research, Vol. 109, 11, DOI 10:1029/2004 JB003176MantleTectonics, geochronology
DS200612-0936
2006
Tackley, P.J.Mittelstaedt, E., Tackley, P.J.Plume heat flow is much lower than CMB heat flow.Earth and Planetary Science Letters, Vol. 241, 1-2, pp. 202-210.MantleGeothermometry
DS200612-1405
2005
Tackley, P.J.Tackley, P.J., Xie, S., Nakagawa, T., Hernlund, J.W.Numerical and laboratory studies of mantle convection: philosphy, accomplishments and thermochemical structure and evolution.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 83-100.MantleConvection
DS200712-0239
2007
Tackley, P.J.Deschamps, F., Tackley, P.J.The mode of mantle convection: exploring the model space and comparing with probabilistic tomography.Plates, Plumes, and Paradigms, 1p. abstract p. A219.MantleConvection
DS200712-0384
2007
Tackley, P.J.Grigne, C., Labrosse, S., Tackley, P.J.Convection under a lid of finite conductivity in wide aspect ratio models: effect of continents on the rate of mantle flow.Journal of Geophysical Research, Vol. 112, B8, B08403MantleConvection
DS200712-0385
2007
Tackley, P.J.Grigne, C., Labrosse, S., Tackley, P.J.Convection under a lid of finite conductivity in wide aspect ratio models: heat flux scaling and application to continents.Journal of Geophysical Research, Vol. 112, B8, B08402MantleConvection
DS200712-0430
2007
Tackley, P.J.Hernlund, J.W., Tackley, P.J.Some dynamical consequences of partial melting in Earth's deep mantle.Physics of the Earth and Planetary Interiors, Vol. 162, 1-2, pp. 149-163.MantleMelting
DS200712-0431
2007
Tackley, P.J.Hernlund, J.W., Tackley, P.J.Some dynamical consequences of partial melting in Earth's deep mantle.Physics of the Earth and Planetary Interiors, Vol. 162, 1-2, pp. 149-163.MantleMelting
DS200812-0419
2008
Tackley, P.J.Golabek, G.J., Schmelling, H., Tackley, P.J.Earth's core formation aided by flow channelling instabilities induced by iron diapirs.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 24-33.MantleCore, iron
DS200812-1147
2007
Tackley, P.J.Tackley, P.J., Nakagawa, T., Hernlund, J.W.Influence of the post perovskite transition on thermal and thermo-chemical mantle convection.AGU American Geophysical Union Monograph, No. 174, pp. 229-248.MantleGeothermometry
DS200912-0297
2008
Tackley, P.J.Hernlund, J.W., Tackley, P.J.Modelling mantle convection in the spherical annulus.Physics of the Earth and Planetary Interiors, Vol. 171, 1-4, pp. 48-54.MantleConvection
DS201112-1022
2011
Tackley, P.J.Tackley, P.J.Dynamics and evolution of the deep mantle resulting from thermal, chemical, phase and melting effects.Earth Science Reviews, in press available,MantleConvection, boundary, D'
DS201212-0509
2012
Tackley, P.J.Nakagawa, T., Tackley, P.J.Influence of magmatism on mantle cooling, surface heat flow and Urey ratio.Earth and Planetary Science Letters, Vol. 329-330, pp. 1-10.MantleGeothermometry
DS201212-0594
2012
Tackley, P.J.Rolf, T., Coltice, N.,Tackley, P.J.Linking continental drift, plate tectonics and the thermal state of the Earth's mantle.Earth and Planetary Science Letters, Vol. 351-352, pp. 134-145.MantleTectonics
DS201212-0715
2012
Tackley, P.J.Tackley, P.J.Dynamics and evolution of the deep mantle resulting from thermal, chemical, phase and melting effects.Earth Science Reviews, Vol. 110, 1-4, pp. 1-25.MantleGeothermometry
DS201312-0624
2013
Tackley, P.J.Nagagawa, T., Tackley, P.J.Implications of high core thermal conductivity on Earth's coupled mantle and core evolution.Geophysical Research Letters, Vol. 40, 11, pp. 2652-2656.MantleGeothermometry
DS201412-0048
2014
Tackley, P.J.Bello, L., Coltice, N., Rolf, T., Tackley, P.J.On the predictability limit of convection models of the Earth's mantle.Geochemistry, Geophysics, Geosystems: G3, Vol. 15, 6, pp. 2319-2328.MantleConvection
DS201601-0033
2015
Tackley, P.J.Nakagawa, T., Tackley, P.J.Influence of plate tectonic mode on the coupled thermochemical evolution of Earth's mantle and core.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 10, pp. 3400-3413.MantleGeothermometry

Abstract: We investigate the influence of tectonic mode on the thermochemical evolution of simulated mantle convection coupled to a parameterized core cooling model. The tectonic mode is controlled by varying the friction coefficient for brittle behavior, producing the three tectonic modes: mobile lid (plate tectonics), stagnant lid, and episodic lid. The resulting compositional structure of the deep mantle is strongly dependent on tectonic mode, with episodic lid resulting in a thick layer of subducted basalt in the deep mantle, whereas mobile lid produces only isolated piles and stagnant lid no basaltic layering. The tectonic mode is established early on, with subduction initiating at around 60 Myr from the initial state in mobile and episodic cases, triggered by the arrival of plumes at the base of the lithosphere. Crustal production assists subduction initiation, increasing the critical friction coefficient. The tectonic mode has a strong effect on core evolution via its influence on deep mantle structure; episodic cases in which a thick layer of basalt builds up experience less core heat flow and cooling and a failed geodynamo. Thus, a continuous mobile-lid mode existing from early times matches Earth's mantle structure and core evolution better than an episodic mode characterized by large-scale flushing (overturn) events.
DS201607-1307
2016
Tackley, P.J.Mallard, C., Coltice, N., Seton, M., Muller, R.D., Tackley, P.J.Subduction controls the distribution and fragmentation of Earth's tectonic plates.Nature, available eprintMantleSubduction, melting

Abstract: The theory of plate tectonics describes how the surface of Earth is split into an organized jigsaw of seven large plates1 of similar sizes and a population of smaller plates whose areas follow a fractal distribution2, 3. The reconstruction of global tectonics during the past 200 million years4 suggests that this layout is probably a long-term feature of Earth, but the forces governing it are unknown. Previous studies3, 5, 6, primarily based on the statistical properties of plate distributions, were unable to resolve how the size of the plates is determined by the properties of the lithosphere and the underlying mantle convection. Here we demonstrate that the plate layout of Earth is produced by a dynamic feedback between mantle convection and the strength of the lithosphere. Using three-dimensional spherical models of mantle convection that self-consistently produce the plate size -frequency distribution observed for Earth, we show that subduction geometry drives the tectonic fragmentation that generates plates. The spacing between the slabs controls the layout of large plates, and the stresses caused by the bending of trenches break plates into smaller fragments. Our results explain why the fast evolution in small back-arc plates7, 8 reflects the marked changes in plate motions during times of major reorganizations. Our study opens the way to using convection simulations with plate-like behaviour to unravel how global tectonics and mantle convection are dynamically connected.
DS201610-1854
2016
Tackley, P.J.Crameri, F., Tackley, P.J.Subduction initiation from a stagnant lid and global overturn: new insights from numerical models with a free surface.Progress in Earth and Planetary Science, Open accessMantleConvection, geodynamics

Abstract: Subduction initiation is a key in understanding the dynamic evolution of the Earth and its fundamental difference to all other rocky planetary bodies in our solar system. Despite recent progress, the question about how a stiff, mostly stagnant planetary lid can break and become part in the global overturn of the mantle is still unresolved. Many mechanisms, externally or internally driven, are proposed in previous studies. Here, we present the results on subduction initiation obtained by dynamically self-consistent, time-dependent numerical modelling of mantle convection. We show that the stress distribution and resulting deformation of the lithosphere are strongly controlled by the top boundary formulation: A free surface enables surface topography and plate bending, increases gravitational sliding of the plates and leads to more realistic, lithosphere-scale shear zones. As a consequence, subduction initiation induced by regional mantle flow is demonstrably favoured by a free surface compared to the commonly applied, vertically fixed (i.e. free-slip) surface. In addition, we present global, three-dimensional mantle convection experiments that employ basal heating that leads to narrow mantle plumes. Narrow mantle plumes impinging on the base of the plate cause locally weak plate segments and a large topography at the lithosphere-asthenosphere boundary. Both are shown to be key to induce subduction initiation. Finally, our model self-consistently reproduces an episodic lid with a fast global overturn due to the hotter mantle developed below a former stagnant lid. We conclude that once in a stagnant-lid mode, a planet (like Venus) might preferentially evolve by temporally discrete, global overturn events rather than by a continuous recycling of lid and that this is something worth testing more rigorously in future studies.
DS201706-1102
2017
Tackley, P.J.Rozel, A.B., Golabek, G.J., Jain, C., Tackley, P.J., Gerya, T.Continental crust formation on early Earth controlled by intrusive magmatism.Nature, online availableMantlegeodynamics

Abstract: The global geodynamic regime of early Earth, which operated before the onset of plate tectonics, remains contentious. As geological and geochemical data suggest hotter Archean mantle temperature1, 2 and more intense juvenile magmatism than in the present-day Earth3, 4, two crust-mantle interaction modes differing in melt eruption efficiency have been proposed: the Io-like heat-pipe tectonics regime dominated by volcanism5, 6 and the “Plutonic squishy lid” tectonics regime governed by intrusive magmatism, which is thought to apply to the dynamics of Venus7, 8, 9. Both tectonics regimes are capable of producing primordial tonalite-trondhjemite-granodiorite (TTG) continental crust5, 10 but lithospheric geotherms and crust production rates as well as proportions of various TTG compositions differ greatly9, 10, which implies that the heat-pipe and Plutonic squishy lid hypotheses can be tested using natural data11. Here we investigate the creation of primordial TTG-like continental crust using self-consistent numerical models of global thermochemical convection associated with magmatic processes. We show that the volcanism-dominated heat-pipe tectonics model results in cold crustal geotherms and is not able to produce Earth-like primordial continental crust. In contrast, the Plutonic squishy lid tectonics regime dominated by intrusive magmatism results in hotter crustal geotherms and is capable of reproducing the observed proportions of various TTG rocks. Using a systematic parameter study, we show that the typical modern eruption efficiency of less than 40 per cent12 leads to the production of the expected amounts of the three main primordial crustal compositions previously reported from field data4, 11 (low-, medium- and high-pressure TTG). Our study thus suggests that the pre-plate-tectonics Archean Earth operated globally in the Plutonic squishy lid regime rather than in an Io-like heat-pipe regime.
DS201901-0070
2018
Tackley, P.J.Rolf, T., Capitanio, F.A., Tackley, P.J.Constraints on mantle viscosity structure from continental drift histories in spherical mantle convection models.Tectonophysics, Vol. 746, pp. 339-351.Mantleplate tectonics

Abstract: Earth's continents drift in response to the force balance between mantle flow and plate tectonics and actively change the plate-mantle coupling. Thus, the patterns of continental drift provide relevant information on the coupled evolution of surface tectonics, mantle structure and dynamics. Here, we investigate rheological controls on such evolutions and use surface tectonic patterns to derive inferences on mantle viscosity structure on Earth. We employ global spherical models of mantle convection featuring self-consistently generated plate tectonics, which are used to compute time-evolving continental configurations for different mantle and lithosphere structures. Our results highlight the importance of the wavelength of mantle flow for continental configuration evolution. Too strong short-wavelength components complicate the aggregation of large continental clusters, while too stable very long wavelength flow tends to enforce compact supercontinent clustering without reasonable dispersal frequencies. Earth-like continental drift with episodic collisions and dispersals thus requires a viscosity structure that supports long-wavelength flow, but also allows for shorter-wavelength contributions. Such a criterion alone is a rather permissive constraint on internal structure, but it can be improved by considering continental-oceanic plate speed ratios and the toroidal-poloidal partitioning of plate motions. The best approximation of Earth's recent tectonic evolution is then achieved with an intermediate lithospheric yield stress and a viscosity structure in which oceanic plates are ~ 103 × more viscous than the characteristic upper mantle, which itself is ~ 100-200 × less viscous than the lowermost mantle. Such a structure causes continents to move on average ~ (2.2 ± 1.0) × slower than oceanic plates, consistent with estimates from present-day and from plate reconstructions. This does not require a low viscosity asthenosphere globally extending below continental roots. However, this plate speed ratio may undergo strong fluctuations on timescales of several 100 Myr that may be linked to periods of enhanced continental collisions and are not yet captured by current tectonic reconstructions.
DS201905-1047
2019
Tackley, P.J.Jain, C., Rozel, A.B., Tackley, P.J.Quantifying the correlation between mobile continents and elevated temperatures in the subcontinental mantle.Geochemistry, Geophysics, Geosystems, Vol. 20, 3, pp. 1358-1386.Mantlegeothermometry

Abstract: Continents influence the mantle's convective wavelength and the heat flow escaping from the planet's surface. Over the last few decades, many numerical and analytical studies have contributed to the debate about whether the continents can warm up the subcontinental mantle or not and if they do, then to what extent? However, a consensus regarding the exact nature and magnitude of this correlation between continents and elevated temperatures in the subcontinental mantle remains to be achieved. By conducting a systematic parameter study using 2-D global mantle convection simulations with mobile continents, we provide qualitative and quantitative observations on the nature of this correlation. In our incompressible and compressible convection models, we observe the general processes of downwellings bringing cold material into the mantle along continental margins and a subsequent buildup of warm thermal anomalies underneath the continents. We compute the amplitude and degree of this correlation using spectral decomposition of the temperature and composition fields. The dominant degree of correlation evolves with time and changes with continental configuration. Using simple empirical fits, we observe that this correlation decreases with increasing core temperature, number of continents, internal heating, or decreasing reference viscosity. We also report simple regressions of the time dependence of this correlation. Additionally, we show that decompression melting as a result of a mantle upwelling or small-scale sublithospheric convection leads to voluminous volcanism. The emplacement of this dense basalt-eclogite material breaks the continents apart and destroys the correlation.
DS201908-1780
2019
Tackley, P.J.Jain, C., Rozel, A.B., Tackley, P.J., Sanan, P., Gerya, T.V.Growing primordial continental crust self-consistently in global mantle convection models.Gondwana Research, Vol. 73, pp. 96-122.Mantlegeothermometry

Abstract: The majority of continental crust formed during the hotter Archean was composed of Tonalite-Trondhjemite-Granodiorite (TTG) rocks. In contrast to the present-day loci of crust formation around subduction zones and intra-plate tectonic settings, TTGs are formed when hydrated basalt melts at garnet-amphibolite, granulite or eclogite facies conditions. Generating continental crust requires a two step differentiation process. Basaltic magma is extracted from the pyrolytic mantle, is hydrated, and then partially melts to form continental crust. Here, we parameterise the melt production and melt extraction processes and show self-consistent generation of primordial continental crust using evolutionary thermochemical mantle convection models. To study the growth of TTG and the geodynamic regime of early Earth, we systematically vary the ratio of intrusive (plutonic) and eruptive (volcanic) magmatism, initial core temperature, and internal friction coefficient. As the amount of TTG that can be extracted from the basalt (or basalt-to-TTG production efficiency) is not known, we also test two different values in our simulations, thereby limiting TTG mass to 10% or 50% of basalt mass. For simulations with lower basalt-to-TTG production efficiency, the volume of TTG crust produced is in agreement with net crustal growth models but overall crustal (basaltic and TTG) composition stays more mafic than expected from geochemical data. With higher production efficiency, abundant TTG crust is produced, with a production rate far exceeding typical net crustal growth models but the felsic to mafic crustal ratio follows the expected trend. These modelling results indicate that (i) early Earth exhibited a "plutonic squishy lid" or vertical-tectonics geodynamic regime, (ii) present-day slab-driven subduction was not necessary for the production of early continental crust, and (iii) the Archean Earth was dominated by intrusive magmatism as opposed to "heat-pipe" eruptive magmatism.
DS202004-0547
2020
Tackley, P.J.Yan, J., Ballmer, M.D., Tackley, P.J.The evolution and distribution of recycled oceanic crust in the Earth's mantle: insight from geodynamic models.Earth and Planetary Science Letters, Vol. 537, 116171 12p. PdfMantlegeothermometry

Abstract: A better understanding of the Earth's compositional structure is needed to place the geochemical record of surface rocks into the context of Earth accretion and evolution. Cosmochemical constraints imply that lower-mantle rocks may be enriched in silica relative to upper-mantle pyrolite, whereas geophysical observations support whole-mantle convection and mixing. To resolve this discrepancy, it has been suggested that subducted mid-ocean ridge basalt (MORB) segregates from subducted harzburgite to accumulate in the mantle transition zone (MTZ) and/or the lower mantle. However, the key parameters that control basalt segregation and accumulation remain poorly constrained. Here, we use global-scale 2D thermochemical convection models to investigate the influence of mantle-viscosity profile, planetary-tectonic style and bulk composition on the evolution and distribution of mantle heterogeneity. Our models robustly predict that, for all cases with Earth-like tectonics, a basalt-enriched reservoir is formed in the MTZ, and a harzburgite-enriched reservoir is sustained at 660~800 km depth, despite ongoing whole-mantle circulation. The enhancement of basalt and harzburgite in and beneath the MTZ, respectively, are laterally variable, ranging from ~30% to 50% basalt fraction, and from ~40% to 80% harzburgite enrichment relative to pyrolite. Models also predict an accumulation of basalt near the core mantle boundary (CMB) as thermochemical piles, as well as moderate enhancement of most of the lower mantle by basalt. While the accumulation of basalt in the MTZ does not strongly depend on the mantle-viscosity profile (explained by a balance between basalt delivery by plumes and removal by slabs at the given MTZ capacity), that of the lowermost mantle does: lower-mantle viscosity directly controls the efficiency of basalt segregation (and entrainment) near the CMB; upper-mantle viscosity has an indirect effect through controlling slab thickness. Finally, the composition of the bulk-silicate Earth may be shifted relative to that of upper-mantle pyrolite, if indeed significant reservoirs of basalt exist in the MTZ and lower mantle.
DS202005-0772
2020
Tackley, P.J.Yan, J., Ballmer, M.D., Tackley, P.J.The evolutiom and distribution of recycled oceanic crust in the Earth's mantle: insight from geodynamic models. ( harzburgite)Earth and Planetary Science Letters, Vol. 537, 116171, 12p. PdfMantlegeodynamics

Abstract: A better understanding of the Earth's compositional structure is needed to place the geochemical record of surface rocks into the context of Earth accretion and evolution. Cosmochemical constraints imply that lower-mantle rocks may be enriched in silica relative to upper-mantle pyrolite, whereas geophysical observations support whole-mantle convection and mixing. To resolve this discrepancy, it has been suggested that subducted mid-ocean ridge basalt (MORB) segregates from subducted harzburgite to accumulate in the mantle transition zone (MTZ) and/or the lower mantle. However, the key parameters that control basalt segregation and accumulation remain poorly constrained. Here, we use global-scale 2D thermochemical convection models to investigate the influence of mantle-viscosity profile, planetary-tectonic style and bulk composition on the evolution and distribution of mantle heterogeneity. Our models robustly predict that, for all cases with Earth-like tectonics, a basalt-enriched reservoir is formed in the MTZ, and a harzburgite-enriched reservoir is sustained at 660~800 km depth, despite ongoing whole-mantle circulation. The enhancement of basalt and harzburgite in and beneath the MTZ, respectively, are laterally variable, ranging from ~30% to 50% basalt fraction, and from ~40% to 80% harzburgite enrichment relative to pyrolite. Models also predict an accumulation of basalt near the core mantle boundary (CMB) as thermochemical piles, as well as moderate enhancement of most of the lower mantle by basalt. While the accumulation of basalt in the MTZ does not strongly depend on the mantle-viscosity profile (explained by a balance between basalt delivery by plumes and removal by slabs at the given MTZ capacity), that of the lowermost mantle does: lower-mantle viscosity directly controls the efficiency of basalt segregation (and entrainment) near the CMB; upper-mantle viscosity has an indirect effect through controlling slab thickness. Finally, the composition of the bulk-silicate Earth may be shifted relative to that of upper-mantle pyrolite, if indeed significant reservoirs of basalt exist in the MTZ and lower mantle.
DS1960-1222
1969
Taddei, M.Taddei, M.India #1Barrie And Jenkins, UNKNOWN.IndiaHistory
DS1996-1397
1996
Tadesse, T.Tadesse, T.Structure across a possible intra-oceanic suture zone in the low grade PanAfrican rocks of northern EthiopiaJournal of African Earth Sciences, Vol. 23, No. 3, Oct. 1, pp. 375-382GlobalStructure, Tectonics
DS201312-0981
2013
Tadeusz, S.Wolkowicz, S., Bojakowska, I., Wolkowicz, K., Tadeusz, S.Trace elements in CatAnd a carbonatitic massif (SW Angola).Goldschmidt 2013, 1p. AbstractAfrica, AngolaCarbonatite
DS1995-0902
1995
Tadjibae, G.T.Kadik, A.A., Zharkova, E.V., Lutkov, V.S., Tadjibae, G.T.Redox state of peridotite xenoliths from south and middle Tian Shan, experimental determination. (Russian)Geochemistry International (Geokhimiya), (Russian), No. 8, August pp. 1094-99. #ry508ChinaXenoliths
DS201212-0635
2012
Tadjou, J-M.Shandini, Y., Tadjou, J-M.Interpreting gravity anomalies in south Cameroon, central Africa.Earth Sciences Journal,, Vol. 16, 1, pp. 5-9.Africa, CameroonGeophysics - gravity
DS200712-1053
2007
Taduno, J.A.Taduno, J.A.On the motion of Hawaii and other mantle plumes.Chemical Geology, Vol. 241, 3-4, pp. 234-247.MantleTectonics
DS1996-0706
1996
TadzhivayevKadik, A.A., Zharkova, Ye.V., Lutkov, V.S., TadzhivayevDetermination of the redox state of central and south Tian Shun mantlexenoliths.Geochemistry International, Vol. 33, No. 7, pp. 33-38.Russia, Tajikistan, MantleXenoliths
DS1985-0476
1985
Tagai, T.Nakazawa, H., Tagai, T., Hirai, H., Satow, Y.X-ray Section Topographs of a Cube Shaped DiamondMineralogical Journal, Vol. 12, No. 6, pp. 245-250GlobalDiamond Morphology
DS200712-1054
2007
Tagawa, M.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one-sided subduction.Pure and Applied Geophysics, Pageoph, Vol. 164, 5, pp. 879-907.MantleSubduction
DS200712-1055
2007
Tagawa, M.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one-sided subduction.Pure and Applied Geophysics, Pageoph, Vol. 164, 5, pp. 879-907.MantleSubduction
DS200712-1056
2007
Tagawa, M.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one sided subduction.Pure and Applied Geophysics, Pageoph, Vol. 164, 5, May pp. 879-907.MantleSubduction
DS200712-1057
2007
Tagawa, M.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one-sided subduction.Pure and Applied Geophysics, Vol. 164, 5, May pp. 879-907.MantleSubduction, convection
DS200712-1058
2007
Tagawa, M.Tagawa, M., Nakakuki, T., Tajima, F.Dynamical modeling of trench retreat driven by the slab interaction with the mantle transition zone.Earth Planets and Space, Vol. 59, 2, pp. 65-74.MantleSubduction
DS200712-1059
2007
Tagawa, M.Tagawa, M., Nakakuki, T., Tajima, F.Dynamical modeling of trench retreat driven by the slab interaction with the mantle transition zone.Earth Planets and Space, Vol. 59, 2, pp. 65-74.MantleSubduction
DS200812-0785
2008
Tagawa, M.Nakakuki, T., Hamada, C., Tagawa, M.Generation and driving forces of plate like motion and asymmetric subduction in dynamical models of an integrated mantle lithosphere system.Physics of the Earth and Planetary Interiors, Vol. 166, 3-4, pp. 128-146.MantleSubduction
DS201912-2808
2019
Tagawa, S.Oka, K., Hirose, K., Tagawa, S., Kidokoro, Y., Nakajima, Y., Kuwayama, Y., Morard, G., Coudurier, N., Fiquet, G.Melting in the Fe-FeO system to 204 GPa: implications for oxygen in Earth's core.American Mineralogist, Vol. 104, pp. 1603-1607.Mantlemelting

Abstract: We performed melting experiments on Fe-O alloys up to 204 GPa and 3500 K in a diamond-anvil cell (DAC) and determined the liquidus phase relations in the Fe-FeO system based on textural and chemical characterizations of recovered samples. Liquid-liquid immiscibility was observed up to 29 GPa. Oxygen concentration in eutectic liquid increased from >8 wt% O at 44 GPa to 13 wt% at 204 GPa and is extrapolated to be about 15 wt% at the inner core boundary (ICB) conditions. These results support O-rich liquid core, although oxygen cannot be a single core light element. We estimated the range of possible liquid core compositions in Fe-O-Si-C-S and found that the upper bounds for silicon and carbon concentrations are constrained by the crystallization of dense inner core at the ICB.
DS1860-0323
1879
Tagore, S.M.Tagore, S.M.Mani-mala, or a Treatise on GemsCalcutta: I.c. Ross And Co. Stanhope Press, TWO VOLS. Vol. I, 506P.; Vol. II, 540P.IndiaDiamonds Notable, History
DS201606-1123
2016
Taguchi, T.Taguchi, T., Enami, M., Kouketsu, Y.Prograde evolution of Sulu UHP metamorphic rock in Yangzhuang Junan region, deduced by combined Ramas and petrological studies.Journal of Metamorphic Geology, in press availableChinaUHP - coesite, eclogite
DS201902-0326
2019
Taguchi, T.Taguchi,T., Igami, Y., Miyake, A., Masake, E.Factors affecting preservation of coesite in ultrahigh-pressure metamorphic rocks: insights from TEM observations of dislocations within kyanite Sulu China.Journal of Metamorphic Geology, https://doi.org/10.1111/jmg.12470Chinacoesite

Abstract: To understand the preservation of coesite inclusions in ultrahigh-pressure (UHP) metamorphic rocks, an integrated petrological, Raman spectroscopic and focused ion beam (FIB) system-transmission electron microscope (TEM) study was performed on a UHP kyanite eclogite from the Sulu belt in eastern China. Coesite grains have been observed only as rare inclusions in kyanite from the outer segment of garnet and in the matrix. Raman mapping analysis shows that a coesite inclusion in kyanite from the garnet rim records an anisotropic residual stress and retains a maximum residual pressure of approximately 0.35 GPa. TEM observations show quartz is absent from the coesite inclusion-host kyanite grain boundaries. Numerous dislocations and sub-grain boundaries are present in the kyanite, but dislocations are not confirmed in the coesite. In particular, dislocations concentrate in the kyanite adjacent to the boundary with the coesite inclusion, and they form a dislocation concentration zone with a dislocation density of ~109 cm-2. A high-resolution TEM image and a fast Fourier transform-filtered image reveal that a tiny dislocation in the dislocation concentration zone is composed of multiple edge dislocations. The estimated dislocation density in most of the kyanite away from the coesite inclusion-host kyanite grain boundaries is ~108 cm-2, being lower than that in kyanite adjacent to the coesite. In the case of a coesite inclusion in a matrix kyanite, using Raman and TEM analyses we could not identify any quartz at the grain boundaries. Dislocations are not observed in the coesite, but numerous dislocations and stacking faults are developed in the kyanite. The estimated overall dislocation density in the coesite-bearing matrix kyanite is ~108 cm-2, but a high dislocation density region of ~109 cm-2 is also present near the coesite inclusion-host kyanite grain boundaries. Inclusion and matrix kyanite grains with no coesite have dislocation densities of =108 cm-2. Dislocation density is generally reduced during an annealing process, but our results show that not all dislocations in the kyanite have recovered uniformly during exhumation of the UHP rocks. Hence, one of the key factors acting as a buffer to inhibit the coesite to quartz transformation is the mechanical interaction between the host and the inclusion that lead to the formation of dislocations in the kyanite. The kyanite acts an excellent pressure container that can preserve coesite during the decompression of rocks from UHP conditions. The search for and study of inclusions in kyanite may be a more suitable approach for tracing the spatial distribution of UHP metamorphic rocks.
DS201904-0786
2019
Taguchi, T.Taguchi, T., Igami, Y., Miyake, A., Enami, M.Factors affecting preservation of coesite in ultrahigh-pressure metamorphic rocks: insights from TEM observations of dislocations within kyanite. Sulu UHPJournal of Metamorphic Geology, Vol. 37, 3, pp. 401-414.Chinacoesite

Abstract: To understand the preservation of coesite inclusions in ultrahigh-pressure (UHP) metamorphic rocks, an integrated petrological, Raman spectroscopic and focussed ion beam (FIB) system-transmission electron microscope (TEM) study was performed on a UHP kyanite eclogite from the Sulu belt in eastern China. Coesite grains have been observed only as rare inclusions in kyanite from the outer segment of garnet and in the matrix. Raman mapping analysis shows that a coesite inclusion in kyanite from the garnet rim records an anisotropic residual stress and retains a maximum residual pressure of ~0.35 GPa. TEM observations show quartz is absent from the coesite inclusion-host kyanite grain boundaries. Numerous dislocations and sub-grain boundaries are present in the kyanite, but dislocations are not confirmed in the coesite. In particular, dislocations concentrate in the kyanite adjacent to the boundary with the coesite inclusion, and they form a dislocation concentration zone with a dislocation density of ~109 cm-2. A high-resolution TEM image and a fast Fourier transform-filtered image reveal that a tiny dislocation in the dislocation concentration zone is composed of multiple edge dislocations. The estimated dislocation density in most of the kyanite away from the coesite inclusion-host kyanite grain boundaries is ~108 cm-2, being lower than that in kyanite adjacent to the coesite. In the case of a coesite inclusion in a matrix kyanite, using Raman and TEM analyses, we could not identify any quartz at the grain boundaries. Dislocations are not observed in the coesite, but numerous dislocations and stacking faults are developed in the kyanite. The estimated overall dislocation density in the coesite-bearing matrix kyanite is ~108 cm-2, but a high dislocation density region of ~109 cm-2 is also present near the coesite inclusion-host kyanite grain boundaries. Inclusion and matrix kyanite grains with no coesite have dislocation densities of =108 cm-2. Dislocation density is generally reduced during an annealing process, but our results show that not all dislocations in the kyanite have recovered uniformly during exhumation of the UHP rocks. Hence, one of the key factors acting as a buffer to inhibit the coesite to quartz transformation is the mechanical interaction between the host and the inclusion that lead to the formation of dislocations in the kyanite. The kyanite acts as an excellent pressure container that can preserve coesite during the decompression of rocks from UHP conditions. The search for and study of inclusions in kyanite may be a more suitable approach for tracing the spatial distribution of UHP metamorphic rocks.
DS201412-0460
2014
Tague, K.A.Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alcantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M.Nanodiamond rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP Journal of Geology, Vol 122, 5, pp. 475-506.Global, GreenlandNanodiamonds
DS201502-0069
2014
Tague, K.A.Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M.Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP.Journal of Geology, Vol. 122, Sept. pp. 475-506.South America, BrazilNanodiamonds
DS200712-1060
2006
Tahera Diamond CorporationTahera Diamond CorporationTahera Diamond Corporation announces startegic alliance with Teck Cominco Limited. JerichoTahera Diamond Corporation, Nov. 15, 2p.Canada, NunavutNews item - press release, Teck Cominco
DS200712-1070
2006
Tahey, M.C.Tashey, T.E.Jr., Tahey, M.C.A system to describe the face up color appearance of white and off white polished diamonds.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.142-3. abstract onlyTechnologyDiamond colour grading
DS201012-0895
2010
Taijin, L.Zhonghua, S., Taijin, L., Mendong, S., Jun, S., Jing, D., Xihuan, Z.2010 coated and fracture filled coloured diamond.The Australian Gemmologist, Vol. 24, 1,TechnologyDiamond filling
DS201212-0831
2010
Taijin, L.Zhonghua, S., Taijin, L., Meidong, S.Coated and fracture filled coloured diamond.The Australian Gemmologist, Vol. 24, 2, Apr-June pp.TechnologyDiamond - morphology
DS201212-0832
2011
Taijin, L.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jingjing, S.High quality synthetic yellow orange diamond emerges in China.The Australian Gemmologist, Vol. 24, 7, July-Sept pp.TechnologySynthetics
DS201312-0405
2013
Taijin, L.Hua, C., Zhili, Q., Taijin, L., Stern, R., Stachel, T., Yuan, S., Jian, Z., Jie, K., Shyu, P., Shecai, Q.Variations in carbon isotopic composition in the subcontinental lithospheric mantle beneath the Yangtze and North Chin a cratons; evidence from in-situ analysis of diamonds using SIMS.Chinese Science Bulletin, Vol. 58, 1, pp. 99-107ChinaCraton
DS201511-1894
2014
Taijin, L.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jing, D., Xikuan, Z.Coated and fracture filled coloured diamond.Australian Gemmologist, Vol. 24, 2, pp. 41-43.TechnologyDiamond morphology
DS201511-1895
2014
Taijin, L.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jingjing, S.High quality synthetic yellow orange diamond emerges in China.Australian Gemmologist, Vol. 24, 7, pp. 167-170.ChinaSynthetics
DS1989-0294
1989
Tailor, A.M.Corr, D.G., Tailor, A.M., Cross, A., Hogg, D.C., Lawrence, D.H.Progress in automatic analysis of multi-temporal remotely sensed dataInternational Journal of Remote Sensing, Vol. 10, No. 6, June pp. 1175-1196GlobalRemote sensing, Computer Program
DS1999-0716
1999
TaintonStiefenhofer, J., Voljoen, Tainton, Dobbe, HannwegThe petrology of a mantle xenolith suite from Venetia, South Africa #27th International Kimberlite Conference Nixon, Vol. 2, pp. 836-45.South AfricaXenoliths, petrography, mineral chemistry, geothermomet, Deposit - Venetia
DS1993-0440
1993
Tainton, K.Field, M., Tainton, K.The petrology of core specimens from Le Tac Township kimberliteQuebec Department of Mines, GM 52652, 157p.QuebecExploration - assessment
DS1998-1440
1998
Tainton, K.Tainton, K., Seggie, A., Bayly, B., Tomlinson, QuadlingRegional variation in mantle heat flow within the Tanzanian Craton7th International Kimberlite Conference Abstract, pp. 880-2.TanzaniaGeotherm - garnets, Deposit - Mwadui
DS1991-1687
1991
Tainton, K.M.Tainton, K.M., Browning, P.The Group 2 kimberlite -lamproite connection: some constraints from the Barkly-west district, northern Cape Province, South AfricaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 405-407South AfricaMicaceous kimberlites, Sover-Doornkloof, Sover-North, geochronology
DS1992-1510
1992
Tainton, K.M.Tainton, K.M.The petrogenesis of Group 2 kimberlites and lamproites from the northern Cape Province, South Africa.Ph.d. Thesis University of Cambridge, 270p.South AfricaBarkly West, Aaron, Sover, Doornkloof, North, Bellsbank, Newland, petrography, mineral chemistry, geochemistry
DS1994-1739
1994
Tainton, K.M.Tainton, K.M., McKenzie, D.The generation of kimberlites, lamproites and their source rocksJournal of Petrology, Vol. 35, No. 3, June pp. 787-818.GlobalKimberlites, Lamproites
DS1995-1865
1995
Tainton, K.M.Tainton, K.M.The petrogenesis of Group 2 kimberlite and lamproite magmasProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 597-599.South AfricaKimberlite, Group II, Lamproite, Deposit -Barkly West
DS1998-1413
1998
Tainton, K.M.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
DS1999-0725
1999
Tainton, K.M.Tainton, K.M., Seggie, Bayly, Tomlinson, QuadlingGarnet therombarometry: implications for mantle heat flow within the Tanzanian Craton.7th International Kimberlite Conference Nixon, Vol. 2, pp. 852-60.TanzaniaCraton mineral chemistry, Deposit - Mwadui, Kisumbi, Negezi, Mhunse, Nzega
DS2003-0924
2003
Tainton, K.M.Mdludlu, S., Mabuza, M.B., Tainton, K.M., Sweeney, R.J.A clinopyroxene thermobarometry traverse across Coromandel area, Brazil8 Ikc Www.venuewest.com/8ikc/program.htm, Session 9, POSTER abstractBrazilGeothermometry
DS200412-1285
2003
Tainton, K.M.Mdludlu, S., Mabuza, M.B., Tainton, K.M., Sweeney, R.J.A clinopyroxene thermobarometry traverse across Coromandel area, Brazil.8 IKC Program, Session 9, POSTER abstractSouth America, BrazilCraton studies Geothermometry
DS2002-0857
2002
Taira, A.Kiykawa, S., Taira, A., Byrne, T., Bowring, S., Sano, Y.Structural evolution of the middle Archean coastal Pilbara terrane, western AustraliaTectonics, Vol. 21, No. 5, 10.1029/2001TC001296.AustraliaTectonics - structure
DS200912-0743
2009
Taisne, B.Taisne, B., Jaupart, C.Dike propagation through layered rocks.Journal of Geophysical Research, Vol. 114, B09203MantleSills - not specific to diamonds
DS201112-1023
2011
Taisne, B.Taisne, B., Jaupart, C.Magma expansion and fragmentation in a propagating dyke.Earth and Planetary Science Letters, Vol. 301, 1-2, pp. 146-152.MantleMagmatism, dykes
DS201112-1024
2011
Taisne, B.Taisne, B., Tait, S., Jaupart, C.Conditions for the arrest of a vertical propagating dyke.Bulletin of Volcanology, Vol. 73, 2, pp.MantleMagmatism
DS201112-1025
2011
Taisne, B.Taisne,B., Tait, S.Effect of solidification on a propogating dyke.Journal of Geophysical Research, Vol. 116, B01206, 14p.MantleMagma migration, seismicity
DS201112-0335
2011
TaitFourie, P.H., Zimmermana, U., Beukes, N.J., Naidoo, T., Kobayasji, K., Kosler, J., Nakamura, Tait, TheronProvenance and reconnaissance study of detrital zircons of the Paleozoic Cape Supergroup: revealing the interaction of Kalahari and Rio de la Plat a cratons.International Journal of Earth Sciences, Vol. 100, 2, pp. 527-541.Africa, South Africa, South America, BrazilGeochronology
DS2002-1415
2002
Tait, J.Schaltz, M., Resichmann, T., Tait, J., Bachtadse, V., Bahlburg, H., Martin, U.The Early Paleozoic break up of northern Gondwana, new paleomagnetic andInternational Journal of Earth Sciences, Vol. 91, No. 5, Oct. pp. 838-49.GermanyTectonics, Gondwana
DS201312-0899
2013
Tait, J.Tait, J., Straathof, G., Soderlund, U., Ernst, R.E., Key, R., Jowitt, S.M., Lo, K., Dahmada, M.E.M., N'Diaya, O.The Ahmeyim Great Dyke of Mauritania: a newly dated Archean intrusion.Lithos, Vol. 174, pp. 323-332.Africa, MauritaniaGeochronology
DS201805-0984
2018
Tait, K.Tschauner, O., Huang, S., Greenberg, E., Prakapenka, V.B., Ma, C., Rossman, G.R., Shen, A.H., Zhang, D., Newville, M., Lanzirotti, A., Tait, K.Ice-VII inclusions in diamonds: evidence for aqueous fluid in the Earth's deep mantle. Orapa, ShandongScience, Vol. 359, pp. 1136-1139.Africa, South Africa, Botswana, Congo, Sierra Leone, Chinadiamond inclusions
DS200612-0184
2006
Tait, M.Brown, R.J., Tait, M., Field, M., Sparks, R.S.J.Progressive enlargement and infill of a kimberlite pipe: K2 pipe, Venetia kimberlite field, Limpopo Province, South Africa.Emplacement Workshop held September, 5p. extended abstractAfrica, South AfricaDeposit - K2, Venetia - lithofacies assemblages
DS200712-0119
2007
Tait, M.Brown, R.J., Kavanagh, J., Sparks, R.S.J., Tait, M., Field, M.Mechanically disrupted and chemically weakened zones in segmented dike system cause vent localization: evidence from kimberlite volcanic systems.Geology, Vol. 35, 9, pp. 815-818.Africa, South AfricaDeposit - Swartruggems dike swarm
DS200812-0148
2009
Tait, M.Brown, R.J., Tait, M., Field, M., Sparks, R.S.J.Geology of a complex kimberlite pipe ( K2 pipe), Venetia Mine, South Africa: insights into conduit processes during explosive ultrabasic eruptions.Bulletin Volcanology, Vol. 71, 1, pp. 95-112.Africa, South AfricaDeposit - Venetia
DS200912-0033
2009
Tait, M.Barnett, W., Kurzlaujis, S., Tait, M., Dirks, P.Kimberlite wall rock fragmentation: Venetia K08 pipe development.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyAfrica, South AfricaDeposit - Venetia
DS201112-0060
2011
Tait, M.Barnett, W.P., Kurzlaukis, S., Tait, M., Dirks, P.Kimberlite wall rock fragmentation processes: Venetia K08 pipe development.Bulletin Volcanology, In press available, 18p.Africa, South AfricaGeology - Venetia
DS200612-1406
2006
Tait, M.A.Tait, M.A., Brown, R.J., Mnyama, A.Internal architecture of the Venetia K1 kimberlite: a new geological model and implications for kimberlite emplacement processes, Venetia mine, Limpopo RSA.Emplacement Workshop held September, 5p. abstractAfrica, South AfricaDeposit - Venetia, petrography, facies
DS201212-0233
2012
Tait, M.A.Gernon, T., Brown, R.J., Tait, M.A., Hincks, T.K.The origin of pellatal lapilli in explosive kimberlite eruptions.Nature Communcations, May 7p.Africa, South Africa, LesothoDeposit - Venetia, Letseng-la-Terae
DS201212-0234
2012
Tait, N.Gernon, T.M., Brown, R.J., Tait, N., Hinks, T.K.The origin of pellatal lapilli in explosive kimberlite eruptions.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractTechnologyPetrology
DS1992-1511
1992
Tait, S.Tait, S.Selective preservation of melt inclusions in igneous phenocrystsAmerican Mineralogist, Vol. 77, pp. 146-55.Mantlemetamorphism
DS1994-1740
1994
Tait, S.Tait, S.Magma chambers- convective convictionsNature, Vol. 369, No. 6479, June 2, p. 359MantleMagma chambers
DS1995-0882
1995
Tait, S.Jaupart, C., Tait, S.Dynamics of differentiation in magma reservoirsJournal of Geophysical Research, Vol. 100, No. 9, Sept. 10, pp. 7615-36GlobalMagmatism, Layered intrusions
DS1995-1788
1995
Tait, S.Snyder, D., Tait, S.Replenishment of magma chamber: comparison of fluid mechanic experiments with field relationsContributions to Mineralogy and Petrology, Vol. 122, No. 3, pp. 230-240MantleMagma, Genesis
DS1997-1071
1997
Tait, S.Snyder, D., Crambes, C., Tait, S., Wiebe, R.A.Magma mingling in dikes and sillsJournal of Geology, Vol. 105, No. 1, Jan. pp. 75-86GlobalPetrology - experimental, Composite dikes
DS201112-1024
2011
Tait, S.Taisne, B., Tait, S., Jaupart, C.Conditions for the arrest of a vertical propagating dyke.Bulletin of Volcanology, Vol. 73, 2, pp.MantleMagmatism
DS201112-1025
2011
Tait, S.Taisne,B., Tait, S.Effect of solidification on a propogating dyke.Journal of Geophysical Research, Vol. 116, B01206, 14p.MantleMagma migration, seismicity
DS1996-1398
1996
Tait, S.R.Tait, S.R., Jaupart, C.The production of chemically stratified and accumulate plutonic igneousrocksMineralogical Magazine, Vol. 60, No. 1, Feb pp. 99-114GlobalMagmatic processes, Layered intrusive
DS1999-0698
1999
Tait, S.R.Sparks, R.S.J., Tait, S.R., Yanev, Y.Dense welding caused by volatile resorptionJournal of Geological Society of London, Vol. 156, No. 2, Mar. pp. 217-26.GlobalMagmatism - volconology
DS200812-1027
2008
Tajcmanova, L.Schulmann, K., Lexa, O., Stipska, P., Racek, M., Tajcmanova, L., Konpasek, Edel, Peschler, LehmannVertical extension and horizontal channel flow of orogenic lower crust: key exhumation mechanisms in large hot orogens?Journal of Metamorphic Geology, In press availableEurope, MantleGeophysics - bouguer
DS1984-0722
1984
Taji, Y.Taji, Y.Dgr, Ggr, Molecular Dynamical Codes for Simulating Radiation damages in diamond and Graphite Crystals.*japJapan Atomic Energy Research Institute, *JAP, No. JAERI- 1291, June 36pGlobalDiamond Morphology
DS1993-1567
1993
Tajika, E.Tajika, E., Matsui, T.Degassing history anbd carbon cycle of the earth: from an impact-induced steam atmosphere to the present atmosphereLithos, Vol. 30, No. 3-4, September pp. 267-280MantleCarbon cycle, Degassing atmosphere
DS1998-1441
1998
Tajika, E.Tajika, E.Climate change during the last 150 m years: reconstruction from a carbon cycle modelEarth and Plan. Sci. Lett, Vol. 160, No. 3-4, pp. 695-708GlobalClimate, Carbon cycle
DS2003-1357
2003
Tajika, E.Tajika, E.Faint young Sun and the carbon cycle: implications for the Proterozoic globalEarth and Planetary Science Letters, Vol. 214, 3-4, pp. 443-53.GlobalGeomorphology - carbon - cycle
DS200412-1960
2003
Tajika, E.Tajika, E.Faint young Sun and the carbon cycle: implications for the Proterozoic global glaciations.Earth and Planetary Science Letters, Vol. 214, 3-4, pp. 443-53.GlobalGeomorphology - carbon - cycle
DS200712-1054
2007
Tajima, F.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one-sided subduction.Pure and Applied Geophysics, Pageoph, Vol. 164, 5, pp. 879-907.MantleSubduction
DS200712-1055
2007
Tajima, F.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one-sided subduction.Pure and Applied Geophysics, Pageoph, Vol. 164, 5, pp. 879-907.MantleSubduction
DS200712-1056
2007
Tajima, F.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one sided subduction.Pure and Applied Geophysics, Pageoph, Vol. 164, 5, May pp. 879-907.MantleSubduction
DS200712-1057
2007
Tajima, F.Tagawa, M., Nakakuki, T., Kameyama, M., Tajima, F.The role of history dependent rheology in plate boundary lubrication for generating one-sided subduction.Pure and Applied Geophysics, Vol. 164, 5, May pp. 879-907.MantleSubduction, convection
DS200712-1058
2007
Tajima, F.Tagawa, M., Nakakuki, T., Tajima, F.Dynamical modeling of trench retreat driven by the slab interaction with the mantle transition zone.Earth Planets and Space, Vol. 59, 2, pp. 65-74.MantleSubduction
DS200712-1059
2007
Tajima, F.Tagawa, M., Nakakuki, T., Tajima, F.Dynamical modeling of trench retreat driven by the slab interaction with the mantle transition zone.Earth Planets and Space, Vol. 59, 2, pp. 65-74.MantleSubduction
DS201212-0808
2012
Tajima, F.Yoshida, M., Tajima, F., Honda, S., Morishige, M.The 3D numerical modeling of subduction dynamics: plate stagnation and segmentation, and crustal advection in the wet mantle transition zone.Journal of Geophysical Research, Vol. 117, B4, B0104MantleSubduction
DS200512-0389
2005
Takacs, E.Hajnal, Z., Lewry, J., White, D., Ashton, K., Clowes, R., Stauffer, M., Gyorfi, I., Takacs, E.The Saskatchewan Craton and Hearne Province margin: seismic reflection studies in the western Trans Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 403-419.Canada, Saskatchewan, ManitobaGeophysics - Lithoprobe
DS1984-0283
1984
Takacs, J.Fraser, D.G., Watt, F., Grimes, G.W., Takacs, J.Direct Determination of Strontium Enrichment on Grain Boundaries in a Garnet Lherzolite Xenolith by Proton Microprobe Analysis.Nature., Vol. 312, No. 5992, PP. 352-354.GlobalBlank
DS2002-1113
2002
TakafujiMurakami, M., Hirose, K., Yurimoto, Nakashima, TakafujiWater in Earth's lower mantleScience, No. 5561, Mar. 8, pp. 1885-6.MantleWater
DS200412-1961
2004
Takafuji, N.Takafuji, N., Hirose, K., Ono, S., Xu, F., Mitome, M., Bando, Y.Segregation of core melts by permeable flow in the lower mantle.Earth and Planetary Science Letters, Vol. 224, 3-4, pp. 249-257.MantleGeothermometry - boundary
DS200512-0436
2005
Takafuji, N.Hirose, K., Takafuji, N., Sata, N., Ohishi, Y.Phase transition and density of subducted MORB crust in the lower mantle.Earth and Planetary Science Letters, Vol. 237, 1-2, Aug, 30, pp. 239-251.MantleMineral chemistry, subduction
DS200712-1061
2006
Takafuji, N.Takafuji, N., Fujino, K., Nagai, T., Seto, Y., Hamane, D.Decarbonation reaction of magnesite in subduction slabs at the lower mantle.Physics and Chemistry of Minerals, Vol. 33, 10, pp. 651-654.MantleSubduction
DS200712-1062
2006
Takafuji, N.Takafuji, N., Fujino, K., Nagai, T., Seto, Y., Hamane, D.Decarbonation reaction of magnesite in subducting slabs at the lower mantle.Physics and Chemistry of Minerals, Vol. 33, 10, pp. 651-654.MantleSubduction
DS201501-0033
2014
Takafuma, T.Takafuma, T.Diamond Shades: Point of View .. Answers to 8 key questions on future of global diamond industry.diamondshades.com, 90p. PdfGlobalOverview
DS200812-0474
2008
Takafur, N.Hirose, K., Takafur, N., Fujino, K., Shieh, S.R., Duffy, T.S.Iron partitioning between perovskite and post peroovskite: a transmission electron microscope study.American Mineralogist, Vol. 93, pp. 1678-1681.MantlePhase transition
DS201911-2507
2019
Takagi, T.Akam, C., Simandl, G.J., Lett, R., Paradis, S., Hoshino, M., Kon, Y., Araoka, D., Green, C., Kodama, S., Takagi, T., Chaudhry, M.Comparison of methods for the geochemical determination of rare earth elements: Rock Canyon Creek REE-F-Ba deposit case study, SE British Columbia, Canada.Geochemistry: Exploration, Environment, Analysis, Vol. 19, pp. 414-430.Canada, British Columbiageochemistry

Abstract: Using Rock Canyon Creek REE-F-Ba deposit as an example, we demonstrate the need for verifying inherited geochemical data. Inherited La, Ce, Nd, and Sm data obtained by pressed pellet XRF, and La and Y data obtained by aqua regia digestion ICP-AES for 300 drill-core samples analysed in 2009 were compared to sample subsets reanalysed using lithium metaborate-tetraborate (LMB) fusion ICP-MS, Na2O2 fusion ICP-MS, and LMB fusion-XRF. We determine that LMB ICP-MS and Na2O2 ICP-MS accurately determined REE concentrations in SY-2 and SY-4, and provided precision within 10%. Fusion-XRF was precise for La and Nd at concentrations exceeding ten times the lower detection limit; however, accuracy was not established because REE concentrations in SY-4 were below the lower detection limit. Analysis of the sample subset revealed substantial discrepancies for Ce concentrations determined by pressed pellet XRF in comparison to other methods due to Ba interference. Samarium, present in lower concentrations than other REE compared, was underestimated by XRF methods relative to ICP-MS methods. This may be due to Sm concentrations approaching the lower detection limits of XRF methods, elemental interference, or inadequate background corrections. Aqua regia dissolution ICP-AES results, reporting for La and Y, are underestimated relative to other methods.
DS1984-0783
1984
Takahashi, E.Yamada, H., Takahashi, E.Subsolidus Phase Relations between Coexisting Garnet and Two Pyroxenes at 50 to 100 Kilobar in the System Cao Mgo Al2ossio2.Proceedings of Third International Kimberlite Conference, Vol. 2, PP. 247-255.GlobalGarnet, Composition, Analyses
DS1985-0658
1985
Takahashi, E.Takahashi, E., Scarfe, C.M.Melting of Peridotite to 14 Gpa and the Genesis of KomatiiteNature., Vol. 315, No. 6020, JUNE 13TH. PP. 566-568.Lesotho, United States, Colorado Plateau, New MexicoLherzolite, Kilbourne Hole, Thaba Putsoa, Chemical Analysis
DS1986-0795
1986
Takahashi, E.Takahashi, E.Melting of a dry peridotite KLB 1 up to 14 GPA implications on the origin of peridotitic upper mantleJournal of Geophysical Research, Vol. 92, No. B9, August 10, pp. 9367-9382GlobalMantle
DS1986-0796
1986
Takahashi, E.Takahashi, E., Ito, E., Scarfe, C.M.Melting and subsolidus phase relation of mantle peridotite up to 25 GPaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 208-210New Mexico, LesothoKilborne Hole, Thaba Putsoa
DS1989-0692
1989
Takahashi, E.Ito, E., Takahashi, E.Post spinel transformations in the system Mg2SiO4-Fe2SiO4 and some geophysical implicationsJournal of Geophysical Research, Vol. 94, No. B8, August 10, pp. 10, 637-10646GlobalMantle peridotite, Geophysics
DS1989-1476
1989
Takahashi, E.Takahashi, E.Melting phase relation of mantle peridotites up to25 GPa: implication son magmatism and tectonics in the ArcheanEos, Vol. 70, No. 15, April 11, p. 483. (abstract.)GlobalExperimental Petrology, Magma
DS1989-1514
1989
Takahashi, E.Tronnes, R.G., Takahashi, E., Scarfe, C.M.Stability and phase relations of K-richterite and phlogopite to 15 GPaGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A93. (abstract.)GlobalExperimental petrology, Richterite
DS1990-1440
1990
Takahashi, E.Takahashi, E.Speculations on the Archean mantle: missing link between komatiite and depleted garnet peridotiteJournal of Geophysical Research, Vol. 95, No. B 10, September 10, pp. 15, 941-15, 954GlobalMantle, Garnet peridotite
DS1993-1568
1993
Takahashi, E.Takahashi, E., Jeanloz, R., Rubie, D.Evolution of the earth and planetsAmerican Geophysical Union IUGG Volume, Vol. 14, 159p. approx. $ 30.00GlobalBook -table of contents, ad, Planet -evolution
DS1995-0861
1995
Takahashi, E.Iwamori, H., McKenzie, D., Takahashi, E.Melt generation by isentropic mantle upwellingEarth and Planetary Science Letters, Vol. 134, No. 3-4, Sept. 1, pp. 253-266MantlePlumes, Melts
DS1995-2025
1995
Takahashi, E.Wang, W., Takahashi, E., Sueno, S.Composition of lithospheric mantle beneath Sino-Korea CratonProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 663-665.ChinaOlivine, Xenocrysts
DS1995-2026
1995
Takahashi, E.Wang, W., Takahashi, E., Yurimoto, SueonoInfluence of chromium on rare earth elements (REE) partition behaviour between garnet and basaltic melt.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 666-668.GlobalPetrology -experimental, rare earth elements (REE) -garnets
DS1997-1224
1997
Takahashi, E.Wang, W., Sueno, S., Yurimoto, H., Takahashi, E.Geochemical study of eclogitic mineral inclusions from Chinese diamondsProceedings 30th. I.G.C., Pt. 15, pp. 185-198.ChinaEclogite, Diamond inclusions
DS2001-0837
2001
Takahashi, E.Nishihara, Y., Takahashi, E.Phase relation and physical properties of an Aluminum depleted komatiite to 23 GPa.Earth and Planetary Science Letters, Vol. 190, pp. 65-77.MantleGeophysics - seismics, Piclogite
DS2002-1785
2002
Takahashi, E.Zhao, D., Ochi, F., Takahashi, E.Seismic images of hot spots and mantle plumesGeophysics Monograph, American geophysical Union, No. 128, pp. 349-64.MantleGeophysics - seismics
DS2003-1266
2003
Takahashi, E.Shirasaka, M., Takahashi, E.A genesis of carbonatitic melt within subducting oceanic crusts: high pressure8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractGlobalEclogites and Diamonds, Carbonatite
DS200512-1104
2005
Takahashi, E.Tuff, J., Takahashi, E., Gibson, S.Experimental constraints on the role of garnet pyroxenite in the genesis of high Fe mantle plume derived melts.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, ferro-picrites
DS200512-1105
2005
Takahashi, E.Tuff, J., Takahashi, E., Gibson, S.A.Experimental constraints on the role of garnet pyroxenite in the genesis of high Fe mantle plume derived melts.Journal of Petrology, Vol. 46, 10, pp. 2023-2058.MantleMelting
DS201412-0772
2014
Takahashi, E.Sakurai, M., Tsujino, N., Sakuma, H., Kawamura, K., Takahashi, E.Effects of Al content on water partitioning between orthopyroxene and olivine: implications for lithosphere-asthenosphere boundary.Earth and Planetary Science Letters, Vol. 400, pp. 284-291.MantleFT IR
DS201611-2145
2016
Takahashi, E.Tsujino, N., Yamazaki, D., Takahashi, E.Mantle dynamics inferred from the crystallographic preferred orientation of bridgmanite.Nature, Oct. 20, 15p.MantlePerovskite

Abstract: Seismic shear wave anisotropy1, 2, 3, 4, 5, 6 is observed in Earth’s uppermost lower mantle around several subducted slabs. The anisotropy caused by the deformation-induced crystallographic preferred orientation (CPO) of bridgmanite (perovskite-structured (Mg,Fe)SiO3) is the most plausible explanation for these seismic observations. However, the rheological properties of bridgmanite are largely unknown. Uniaxial deformation experiments7, 8, 9 have been carried out to determine the deformation texture of bridgmanite, but the dominant slip system (the slip direction and plane) has not been determined. Here we report the CPO pattern and dominant slip system of bridgmanite under conditions that correspond to the uppermost lower mantle (25 gigapascals and 1,873 kelvin) obtained through simple shear deformation experiments using the Kawai-type deformation-DIA apparatus10. The fabrics obtained are characterized by [100] perpendicular to the shear plane and [001] parallel to the shear direction, implying that the dominant slip system of bridgmanite is [001](100). The observed seismic shear- wave anisotropies near several subducted slabs1, 2, 3, 4 (Tonga-Kermadec, Kurile, Peru and Java) can be explained in terms of the CPO of bridgmanite as induced by mantle flow parallel to the direction of subduction.
DS201904-0752
2019
Takahashi, E.Kobayashi, M., Sumino, H., Burgess, R., Nakai, S., Iizuka, T., Nagao, J. Kagi, H., Nakamura, M., Takahashi, E., Kogiso, T., Ballentine, C.J.Halogen heterogeneity in the lithosphere and evolution of mantle halogen abundances inferred from intraplate mantle xenoliths. Kilbourne HoleGeochemistry, Geophysics, Geosystems, Vol. 20, 2, pp. 952-973.United States, New Mexicoxenoliths

Abstract: Elemental and isotopic compositions of volatile species such as halogens, noble gases, hydrogen, and carbon can be used to trace the evolution of these species in the Earth. Halogens are important tracers of subduction recycling of surface volatiles into the mantle: however, there is only limited understanding of halogens in the mantle. Here we provide new halogen data of mantle xenoliths from intraplate settings. The mantle xenoliths show a wide range of halogen elemental ratios, which are expected to be related to later processes after the xenoliths formed. A similar primary halogen component is present in the xenoliths sampled from different localities. This suggests that the mantle has the uniform halogen composition over a wide scale. The halogen composition in the convecting mantle is expected to have remained constant over more than 2 billion years, despite subduction of iodine-rich halogens. We used mass balance calculations to gain understanding into evolution rate of I/Cl ratio in the mantle. Calculations suggest that, in order to maintain the I/Cl ratio of the mantle over 2 Gyr, the I/Cl ratio of the subducted halogens must be no more than several times higher than the present-day mantle value.
DS201908-1822
2019
Takahashi, E.Wang, J., Xion, X., Takahashi, E., Zhang, L., Li, L., Liu, X.Oxidation state of arc mantle revealed by partitioning of V, Sc, Ti between mantle minerals and basaltic melts.Journal of Geophysical Research , Vol. 124, 5, pp. 4617-4638.Mantlemelting

Abstract: The oxidation state of the Earth`s mantle, often expressed as oxygen fugacity (fO2), could control the behavior of multivalent elements and thus exert a significant influence on the formation of magmatic ore deposits and the secular evolution of Earth`s atmosphere. Whether arc mantle is more oxidized than oceanic mantle remains a controversial topic. As a multivalent element, partitioning behavior of vanadium is fO2 sensitive and is capable of tracking mantle redox state. However, except fO2, other factors (temperature, pressure, and phase composition) that may affect vanadium partitioning behavior have not been clearly evaluated. Here we conducted high temperature and pressure experiments to determine partition coefficients of vanadium during mantle melting under various fO2 conditions. Combining our and published data, we evaluated the effects of fO2, T, P, and compositions of mineral and melt on the vanadium partitioning using multiple linear regressions. The results indicate that, in addition to fO2, temperature exerts a significant control on the vanadium partitioning. Additionally, we estimated fO2 of the arc mantle via numerical modelling using appropriate partition coefficients for vanadium. Our results clarify and reconcile the discrepancies between previous studies and reveal that arc mantle is generally ~10 times more oxidized than oceanic mantle.
DS200812-1148
2008
Takahashi, F.Takahashi, F., Tsunakawa, H., Matsushima, M., Mochizuki, N., Honkura, Y.Effects of thermally homogeneous structure in the lowermost mantle on the geomagnetic field strength.Earth and Planetary Science Letters, Vol. 272, 3-4, pp. 738-746.MantleGeothermometry
DS1990-0794
1990
Takahashi, K.Kagi, H., Takahashi, K., Masuda, A.Laser-induced luminescence from micro-diamonds of urelliteNatur-wissenschaften, Vol. 77, No. 11, November pp. 531-532GlobalMicrodiamonds, Lumininesence
DS1991-0819
1991
Takahashi, K.Kagi, H., Takahashi, K., Masuda, A.Raman-scattering and laser induced luminesence from micro-diamonds inurelitesMeteoritics, Vol. 26, No. 4, December p. 354GlobalUrelites, Micro-diamonds
DS1994-0861
1994
Takahashi, K.Kagi, H., Takahashi, K., et al.Chemical properties of Central African carbonado and its geneticimplications.Geochimica et Cosmochimica Acta, Vol. 58, No. 12, pp. 2669-2618.Central African RepublicGeochemistry, Carbonado
DS201908-1791
2019
Takahashi, M.Masuda, K., Arai, T., Takahashi, M.Effects of frictional properties of quartz and feldspar in the crust on the depth extent of the seismogenic zone. ** not specific to diamondProgress in Earth and Planetary Science, doi.org/10.1186 /s40645-019-0299-5Mantlegeophysics - seismic

Abstract: The depth extent of the crustal seismogenic zone is closely related to the size of earthquakes. The mechanisms that control the depth of the lower transition of the seismogenic zone are important issues in seismology and disaster mitigation. Laboratory studies have shown that the mechanism of earthquake nucleation is controlled by the frictional properties of fault materials. We measured the velocity dependences of the steady-state friction of quartz and feldspar, two major components of crustal rocks, under dry and wet conditions at temperatures up to 600?°C. In the presence of water, the temperature range over which the velocity dependence of steady-state friction was negative was wider for feldspar than for quartz, thus indicating that the temperature range of earthquake nucleation is wider for feldspar than for quartz. Considering that temperature increases with depth, our findings indicate that the material properties of feldspar likely play a dominant role in limiting the depth extent of the seismogenic zone.
DS1992-1512
1992
Takahashi, N.Takahashi, N.Evidence for melt segregation towards fractures in the Horoman mantle peridotite complexNature, Vol. 359, No. 6390, September 3, pp. 52-55GlobalHoroman complex, Peridotite
DS200512-1106
2005
Takahasi, E.Tuff, J., Takahasi, E., Gibson, S.A.Experimental constraints on the role of garnet pyroxenite in the genesis of high Fe mantle plume derived melts.Journal of Petrology, Vol. 46. 10, Oct. pp. 2023-2058.MantleGarnet pyroxenite melting
DS1998-1283
1998
Takahata, N.SaNo. Y., Takahata, N., Marty, B.Nitrogen recycling in subduction zonesGeophysical Research. Letters, Vol. 25, No. 13, Jul. 1, pp; 2289-92.MantleSubduction
DS200712-0256
2007
Takahata, N.Dobrzhinetskaya, L., Takahata, N., Sano, Y., Green, H.W.Fluid organic matter interaction at high pressure and temperature: evidence from metamorphic diamonds.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 279.Russia, Kazakhstan, Europe, GermanyKokchetav and Erzgebirge
DS200712-0257
2007
Takahata, N.Dobrzhinetskaya, L., Takahata, N., Sano, Y., Green, H.W.Fluid organic matter interaction at high pressure and temperature: evidence from metamorphic diamonds.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 279.Russia, Kazakhstan, Europe, GermanyKokchetav and Erzgebirge
DS201212-0601
2012
Takahata, N.Roulleau, E., Pinti, D.L., Stevenson, R.K., Takahata, N., Sano, Y., Pitre, F.N, Ar and Pb isotopic co-variation in magmatic minerals: discriminating fractionation processes from magmatic sources in Montregian Hills, Quebec, Canada.Chemical Geology, Vol. 326-327, pp. 123-131.Canada, QuebecAlkalic
DS201506-0292
2015
Takahata, N.Pinti, D., Ishida, A., Takahata, N., Sano, Y.Carbon isotopes in a Juin a diamond with carbonate inclusions.Japan Geoscience Union Meeting, SCG16-05 May 28 abstractSouth America, BrazilDeposit - Juina
DS201809-2023
2018
Takahata, N.Fukuyama, K., Kagi, H., Inoue, T., Shinmei, T., Kakizawa, S., Takahata, N., Sano, Y.in corporation of nitrogen into lower mantle minerals under high pressure and high temperature.Goldschmidt Conference, 1p. AbstractMantlenitrogen

Abstract: Nitrogen occupies about 80% of the Earth 's atmosphere and had an impact on the climate in the early Earth. However, the behavior of nitrogen especially in the deep Earth is still unclear. Nitrogen is depleted compared to other volatile elements in deep mantle (Marty et al., 2012). "Missing" nitrogen is an important subject in earth science. In this study, we compared nitrogen incorporation into lower-mantle minerals (bridgmanite, periclase and stishovite) from high-temperature high-pressure experiment using multianvil apparatus installed at Geodynamics Research Center, Ehime University under the conditions of 27 GPa and 1600°C-1900°C. In these experiments, we used Fe-FeO buffer in order to reproduce the redox state of the lower mantle. Two types of starting materials: a powder mixture of SiO2 and MgO and a powder mixture of SiO2, MgO, Al2O3 and Mg(OH)2 were used for starting materials. Nitrogen in recovered samples was analyzed using NanoSIMS installed at Atmosphere and Ocean Research Institute. A series of experimental results revealed that stishovite and periclase can incorporate more nitrogen than bridgmanite. This suggests that periclase, the major mineral in the lower mantle, may be a nitrogen reservoir. Furthermore, the results suggest that stishovite, which is formed by the transition of the SiO2-rich oceanic crustal sedimentary rocks transported to the lower mantle via subducting slabs, can incorporate more nitrogen than bridgmanite (20 ppm nitrogen solubility reported by Yoshioka et al. (2018)). Our study suggests that nitrogen would continue to be supplied to the lower mantle via subducting slabs since approximate 4 billion years ago when the plate tectonics had begun, forming a "Hidden" nitrogen reservoir in the lower mantle.
DS200812-1149
2008
Takaku, M.Takaku, M., Fukao, Y.Fluid mechanical representation of plate boundaries in mantle convection modeling.Physics of the Earth and Planetary Interiors, Vol. 166, 1-2, pp. 44-56.MantleConvection
DS200812-1287
2008
Takakuma, Y.Yamaguchi, H., Salto, I., Kudi, Y., Masuzawa, T., Yamada, T., Kudo, M., Takakuma, Y., Okano, K.Electron emission mechanism of hydrogeneated natural type IIb diamond (111).Diamond and Related Materials, Vol. 17, 2, pp. 162-166.TechnologyType II diamonds
DS200812-1286
2008
TakakuwaYamaguchi, H.,Kudo, Y., Masuzawa, T., Kudo, M., Yamada, Takakuwa, OkanoCombine x-ray photoelectron spectroscopy/ultraviolet photoelectron spectroscopy/field emission spectroscopy for characterization of electron emmision of diamond.Journal of Vacuum Science and Technology B Microelectronics and Nanometer Structures, Vol. 26, 2, pp. 730-734. American Vacuum SocietyTechnologyDiamond emission
DS201112-0950
2011
TakalhashiShestakov, N.V., Gerasimenko, Takalhashi, Tasahara, Bormotov, Bykov,Kolomiets et al.Present tectonics of the southeast of Russia as seen from GPS observations.Geophysical Journal International, Vol. 184, 2, pp. 529-540.RussiaGeodynamics
DS1990-1441
1990
Takama, T.Takama, T., Tsuchiya, K., Kobayash, K.Measurement of the structure factors of diamondAct. Cryst. A., Vol. 46, June 1, pp. 514-517GlobalCrystallography, Diamond morphology
DS1975-0638
1977
Takamura, H.Takamura, H.Mineralogical and Petrological Notes on the Mccloskey's Field Carbonatite Dikes, Ottawa, Canada.Japan Association Min. Petrol. Journal of Economic Geology, Vol. 72, PP. 61-66.Canada, OntarioBlank
DS1987-0726
1987
Takamura, H.Takamura, H.Kimberlite of Ile Bizard, Montreal Canada. *JPNChigaku Kenkyu, *JPN., Vol. 36, No. 1-6, pp. 65-74QuebecBlank
DS1984-0572
1984
Takaoka, M.Ozima, M., Takaoka, M., Nito, O., Zashu, S.Argon isotopic ratios and Potassium, Sodium and other trace element contents in Premier and Finsch mine diamonds contents in Premier and Finsch mine diamondsIn: Material Science of the Earth's interiors, Terra Science Publishing, pp. 375-386South AfricaDiamond Morphology, Geochronology, Isotope
DS1985-0326
1985
Takaoka, N.Kaneoka, I., Takaoka, N., Aoki, K.Possible occurrence of excess 129XE associated with relativelylow40Ar/36Ar ratios in olivine megacryst nodules in South african kimberlitesRock Magnetism and Paleogeophysics, Vol. 12, pp. 89-93South AfricaGeochronology
DS1991-0827
1991
Takaoka, N.Kaneoka, I., Takaoka, N.Evolution of the lithosphere and its interaction with the underlying mantle as inferred from noble gas isotopesAustralian Journal of Earth Science, Vol. 38, pp. 559-567Hawaii, IndiaMantle, Geochronology -noble gas isotopes
DS1985-0659
1985
Takasawa, K.Takasawa, K.Some considerations of the differences of minor componentsAl2O3, Mgo andTiO2 contents of titanomagnetites among various rock series.*JAPChikyu Kagaku, *JAP, Vol. 39, No. 4, pp. 258-271GlobalBlank
DS1993-1063
1993
Takase, T.Miyamoto, M., Takase, T., Mitsuda, Y.Raman spectra of various diamondsMineralogical Journal (Japan), Vol. 16, No. 5, January pp. 246-257.GlobalDiamond morphology, Ureilite meteorites, Spectrometry
DS2003-0701
2003
Takashi, O.Kenji, M., Takashi, O., Yasuda, A., Fujii, T.Connectivity of aqueous fluid in eclogite and its implications for fluid migration in theJournal of Geophysical Research, Vol. 108, B6, 10.1029/2002JB001960 June 6MantleEclogite, Water
DS200412-0973
2003
Takashi, O.Kenji, M., Takashi, O., Yasuda, A., Fujii, T.Connectivity of aqueous fluid in eclogite and its implications for fluid migration in the Earth's interior.Journal of Geophysical Research, Vol. 108, B6, 10.1029/2002 JB001960 June 6MantleEclogite Water
DS200412-0881
2003
Takat, M.Isshiki, E., Irifune, T., Hiropse, K., Ono, S., Ohishi, Y., Watanuki, T., Nishibori, E., Takat, M., Sakata, M.Stability of magnesite and its high pressure form in the lowermost mantle.Nature, No. 6969, pp. 60-62.MantleUHP
DS2002-1575
2002
Takatsuka, M.Takatsuka, M., Gahegan, M.GeoVISTA Studio: a codeless visual programming environnment for geoscientific dat a analysis and visualization.Computers and Geosciences, Vol. 28, 10, pp.1131-44.GlobalComputers - programs
DS2001-0006
2001
TakazawaAgashev, 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
DS1992-1513
1992
Takazawa, E.Takazawa, E., Frey, F.A., Shimizu, N., Obata, M.Geochemical evidence for melt migration and reaction in the upper mantleNature, Vol. 359, No. 6390, September 3, pp. 55-58MantleMelt, Geochemistry
DS1996-1027
1996
Takazawa, E.Navon, O., Frey, F.A., Takazawa, E.Magma transport and metasomatism in the mantle: a critical review of current geochemical models -discAmerican Mineralogist, Vol. 81, May-June pp. 754-765MantleMetasomatism, Magma transport
DS1999-0591
1999
Takazawa, E.Renkamper, M., Halliday, A.N., Takazawa, E.Non-chondritic platinum group element ratios in oceanic mantle lithosphere:petrogenetic signature melt...Earth and Planetary Science Letters, Vol. 172, No. 1-2, Oct. 15, pp. 65-82.MantlePlatinum group elements, Melt percolation
DS200812-0004
2008
Takazawa, E.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
DS202002-0195
2020
Takazawa, E.Klaver, M., Ionov, D.A., Takazawa, E., Elliott, T.The non-chondritic Ni isotope composition of Earth's mantle.Geochimica et Cosmochimica Acta, Vol. 268, pp. 405-421.Mantleperidotites

Abstract: Nickel is a major element in the Earth. Due to its siderophile nature, 93% of Ni is hosted in the core and the Ni isotope composition of the bulk silicate Earth might inform on the conditions of terrestrial core formation. Whether Earth’s mantle is fractionated relative to the chondritic reservoir, and by inference to the core, is a matter of debate that largely arises from the uncertain Ni isotope composition of the mantle. We address this issue through high-precision Ni isotope measurements of fertile- to melt-depleted peridotites and compare these data to chondritic meteorites. Terrestrial peridotites that are free from metasomatic overprint display a limited range in d60/58Ni (deviation of 60Ni/58Ni relative to NIST SRM 986) and no systematic variation with degree of melt depletion. The latter is consistent with olivine and orthopyroxene buffering the Ni budget and isotope composition of the refractory peridotites. As such, the average Ni isotope composition of these peridotites (d60/58Ni = 0.115 ± 0.011‰) provides a robust estimate of the d60/58Ni of the bulk silicate Earth. Peridotites with evidence for melt metasomatism range to heavier Ni isotope compositions where the introduction of clinopyroxene appears to drive an increase in d60/58Ni. This requires a process where melts do not reach isotopic equilibrium with buffering olivine and orthopyroxene, but its exact nature remains obscure. Chondritic meteorites have variability in d60/58Ni due to heterogeneity at the sampling scale. In particular, CI1 chondrites are displaced to isotopically lighter values due to sorption of Ni onto ferrihydrite during parent body alteration. Chondrites less extensively altered than the CI1 chondrites show no systematic differences in d60/58Ni between classes and yield average d60/58Ni = 0.212 ± 0.013‰, which is isotopically heavier than our estimate of the bulk silicate Earth. The notable isotopic difference between the bulk silicate Earth and chondrites likely results from the segregation of the terrestrial core. Our observations potentially provide a novel constraint on the conditions of terrestrial core formation but requires further experimental calibration.
DS200412-1461
2004
Takebe, H.Ohtaka, O., Shimono, M., Ohnisi, N., Fukui, H., Takebe, H., Arima, H., Yamanaka, T.,Kikegawa, T., Kume, S.HIP production of a diamond/ SiC composite and application to high pressure anvils.Physics of the Earth and Planetary Interiors, Vol. 143-144, pp. 587-591.TechnologyUHP
DS1981-0310
1981
Takeda, Y.Naka, S., Suwa, Y., Takeda, Y., Hirano, S.I.Some Observations of Graphite Diamond Transformation by Electro Thermal Analysis.Nippon Kagai Kaishi, (1972), No. 9, PP. 1468-1473.GlobalMineralogy
DS1995-1323
1995
Takeda, Y.Nakada, N., Takeda, Y.Roles of mantle diapir and ductile lower crust on island arc tectonicsTectonophysics, Vol. 246, No. 1-3, June 15, pp. 147-162JapanMantle diapirs, Tectonics -arc
DS2003-1347
2003
Takeda, Y.Suga, T., Takeda, Y., Kono, K., Kishimoto, N., Bandouroko, V.V., Lee, C.G.Radiation effects in diamond induced by negative gold ionsNuclear Instruments and Methods in Physics Research Section B., Vol. 206, pp. 947-51.GlobalDiamond - radiation
DS200412-1947
2003
Takeda, Y.Suga, T., Takeda, Y., Kono, K., Kishimoto, N., Bandouroko, V.V., Lee, C.G.Radiation effects in diamond induced by negative gold ions.Nuclear Instruments and Methods in Physics Research Section B., Vol. 206, pp. 947-51.TechnologyDiamond - radiation
DS200612-1576
2005
Takei, Y.Yoshino, T., Takei, Y., Wark, D.A., Watson, E.B.Grain boundary wetness of texturally equilibrated rocks, with implications for seismic properties of the upper mantle.Journal of Geophysical Research, Vol. 110, B8, B08205, 10.1029/2004 JB003544MantleGeophysics - seismic
DS2001-1148
2001
Takeno, N.Takeno, N.FLASK-SG: a program to compute chemical equilibration temperatures in metamorphic petrologyComp. and Geosci., Vol. 27, No. 10, Dec. pp. 1179-88.GlobalPetrology - metamorphic, Computer - FLASK-SG
DS1997-1137
1997
Takenouchi, S.Takenouchi, S.Mineral resources and mining activity in the Republic of AlbaniaResource Geology, Vol. 47, No. 3, pp. 155-164AlbaniaMineral resources
DS1992-0337
1992
Takeris, D.Dautria, J.M., Dupuy, C., Takeris, D., Dostal, J.Carbonate metasomatism in the lithospheric mantle-peridotitic xenoliths from a melilitic district of the Sahara BasinContributions to Mineralogy and Petrology, Vol. 111, No. 1, June pp. 37-52AfricaMetasomatism, Melilite
DS1992-1514
1992
Takeshi MoriTakeshi MoriThe mechanically incorporated garnet in a harzburgite xenolith from Lesotho kimberlite pipeProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 1, abstract p. 177LesothoLiqhobong pipe, Garnet
DS200812-1039
2008
Takeuchi, A.Senda, R., Kogiso, T., Suzuki, K., Suzuki, T., Uesugi, K., Takeuchi, A., Sukari, Y.Detection of sub micro scale highly siderophile element nugget in kimberlite by synchrontron radiation X ray fluoresence analysis.Goldschmidt Conference 2008, Abstract p.A847.Europe, GreenlandSpectroscopy
DS2003-1046
2003
Takeuchi, M.Park, M.K., Takeuchi, M., Nakazato, H.Electrical resistivity prospecting for geo-environmental investigationExploration Geophysics, Vol. 34, 1-2, pp. 120-124.GlobalGeophysics - resistivity
DS200412-1502
2003
Takeuchi, M.Park, M.K., Takeuchi, M.,Nakazato, H.Electrical resistivity prospecting for geo-environmental investigation.Exploration Geophysics, Vol. 34, 1-2, pp. 120-124.TechnologyGeophysics - resistivity
DS201412-0411
2014
Takeuchi, N.Ititani, R., Takeuchi, N., Kawakatsu, H.Intricate heterogeneous structures of the top 300 km of the Earth's inner core inferred from global array data.II. Frequency dependence of inner core attentuation and its implication.Earth and Planetary Science Letters, Vol. 405, Nov. pp. 231-243.MantleGeophysics - seismics
DS201909-2097
2019
Takeuchi, N.Thorne, M.S., Takeuchi, N. , Shiomi, K.Melting at the edge of a slab in the deepest mantle.Geophysical Research Letters, Vol. 46, 14, pp. 8000-8008.Mantlemelting

Abstract: We use a set of seismic observations recorded globally to investigate the lower mantle beneath Central America. The deepest mantle in this region has been associated with the final resting place of subducted slab material from subduction that initiated approximately 200 million years ago. This ancient subducted material is associated with high seismic wave speeds in the lowermost mantle just above the core-mantle boundary. We find that patches of highly reduced seismic wave speeds, referred to as ultralow-velocity zones (ULVZs), appear to be associated with the border of the high wave speed region, along the border of the subducted slab material. These ULVZ patches are consistent with being regions of partial melt. A possible scenario for their creation is that mid-ocean ridge basalt (MORB), comprising the crust of the subducted slab material, has a low melting point at conditions in the deep earth and may be melting as the slabs reach the bottom of the mantle. Previous experimental work has suggested that MORB will likely partially melt in the deep mantle, yet little evidence for the existence of MORB partial melt has previously been found.
DS200512-1090
2005
Takeuchic, N.Toa, A., Romanaowicza, B., Cap de Villeb, Y., Takeuchic, N.3 D effects of sharp boundaries at the borders of the African and Pacific superplumes: observation and modeling.Earth and Planetary Science Letters, Vol. 233, pp. 137-153.AfricaGeophysics - seismics, boundary
DS1990-0919
1990
Takheris, D.Lesquer, A., Takheris, D., Dauteria, J.M.Geophysical and petrological evidence for the presence of an anomalous upper mantle beneath the Sahara BasinsEarth Planetary Sci. Letters, Vol. 96, No. 3-4, January pp. 407-418AlgeriaGeophysics, Mantle
DS1989-1163
1989
Takigami, Y.Ozima, M., Zashu, S., Takigami, Y., Turner, G.Origin of the anomalous Ar 40-Ar 39 age of Zaire cubic diamonds- excess Ar 40 in pristine mantle fluidsNature, Vol. 337, No. 6204, Jan. 19, pp. 226-229Democratic Republic of CongoMantle, Argon, Geochronology
DS200812-0467
2008
Takley, P.J.Hernlund, J.W., Stevenson, D.J., Takley, P.J.Bouyant melting instabilities beneath extending lithosphere: 1. numerical models.Journal of Geophysical Research, Vol. 113, B4, B04405MantleMelting
DS200812-0468
2008
Takley, P.J.Hernlund, J.W., Stevenson, D.J., Takley, P.J.Bouyant melting instabilities beneath extending lithosphere: 2. linear analysis.Journal of Geophysical Research, Vol. 113, B4, B04406MantleMelting
DS1975-0542
1977
Takoaoka, N.Kaneoka, I., Takoaoka, N., Aoki, K.I.Rare Gases in a Phlogopite Nodule and a Phlogopite Bearing Pegmatite in South African Kimberlites.Earth and Planetary Science Letters, Vol. 34, No. 1, PP. 181-186.South AfricaMineral Chemistry
DS201312-0563
2013
Takpanie, R.Machado, G., Bilodeau, C., Takpanie, R., St.Onge, M., Rayner, N., Skipton, D., From, R., MacKay, C., Young, M., Creason, G., Braden, Z.Regional bedrock mapping, Hall Peninsula, Nunavut.Geoscience Forum 40 NWT, abstract only p. 26Canada, NunavutMapping
DS1980-0204
1980
Takubo, H.Kuge, S., Koizumi, M., Miyamoto, Y., Takubo, H., Kume, S.Synthesis of Prismatic and Tabular Diamond CrystalsMineralogical Magazine., Vol. 43, PP. 579-581.GlobalResearch, Diamond Morphology, Synthetic
DS1994-0943
1994
Takuda, A.Koyagucki, T., Takuda, A.An experimental study on the formation of composite intrusions from zone magma chambersJournal of Volcanology and Geothermal Research, Vol. 59, No. 4, February pp. 261-268GlobalLayered intrusions, Petrology
DS200712-1063
2007
Takuda, N.Takuda, N., Saito, T., Umezawa, H., Okushi, H., Yamasaki, S.The role of boron atoms in heavily boron doped semiconducting homoepitaxial diamond growth - study of surface morphology.Diamond and Related Materials, Vol. 16, 2, Feb., pp. 409-411.TechnologyDiamond morphology
DS1990-1302
1990
Talaeva, T.P.Sarychev, I.K., Talaeva, T.P.Formalized geological -structural model of the Daldyn-Alakit Diamond bearing regionSoviet Geology and Geophysics, Vol. 31, No. 5, pp. 132-136RussiaStructure, Daldyn-Alakit
DS1984-0723
1984
Talati, D.J.Talati, D.J., Patal, K.S.An Occurrence of Vermiculite in Deccan Trap, GujaratGeological Survey India Special Publication, No. 14, pp. 188-189IndiaCarbonatite
DS201711-2514
2017
Talavera, C.Gonzalez-Jimenez, J.M., Camprubi, A., Colas, V., Griffin, W.L., Proenza, J.A., O'Reilly, S.Y., Centeno-Garcia, El., Garcia-Casco, A., Belousova, E., Talavera, C., Farre-de-Pablo, J., Satsukawa, T.The recycling of chromitites in ophiolites from southwestern North America. ( Baja)Lithos, in press available, 52p.United States, Californiachromitites

Abstract: Podiform chromitites occur in mantle peridotites of the Late Triassic Puerto Nuevo Ophiolite, Baja California Sur State, Mexico. These are high-Cr chromitites [Cr# (Cr/Cr + Al atomic ratio = 0.61-0.69)] that contain a range of minor- and trace-elements and show whole-rock enrichment in IPGE (Os, Ir, Ru). That are similar to those of high-Cr ophiolitic chromitites crystallised from melts similar to high-Mg island-arc tholeiites (IAT) and boninites in supra-subduction-zone mantle wedges. Crystallisation of these chromitites from S-undersaturated melts is consistent with the presence of abundant inclusions of platinum-group minerals (PGM) such as laurite (RuS2)-erlichmanite (OsS2), osmium and irarsite (IrAsS) in chromite, that yield TMA ˜ TRD model ages peaking at ~ 325 Ma. Thirty-three xenocrystic zircons recovered from mineral concentrates of these chromitites yield ages (2263 ± 44 Ma to 278 ± 4 Ma) and Hf-O compositions [?Hf(t) = - 18.7 to + 9.1 and 18O values < 12.4‰] that broadly match those of zircons reported in nearby exposed crustal blocks of southwestern North America. We interpret these chromitite zircons as remnants of partly digested continental crust or continent-derived sediments on oceanic crust delivered into the mantle via subduction. They were captured by the parental melts of the chromitites when the latter formed in a supra-subduction zone mantle wedge polluted with crustal material. In addition, the Puerto Nuevo chromites have clinopyroxene lamellae with preferred crystallographic orientation, which we interpret as evidence that chromitites have experienced high-temperature and ultra high-pressure conditions (< 12 GPa and ~ 1600 °C). We propose a tectonic scenario that involves the formation of chromitite in the supra-subduction zone mantle wedge underlying the Vizcaino intra-oceanic arc ca. 250 Ma ago, deep-mantle recycling, and subsequent diapiric exhumation in the intra-oceanic basin (the San Hipólito marginal sea) generated during an extensional stage of the Vizcaino intra-oceanic arc ca. 221 Ma ago. The TRD ages at ~ 325 Ma record a partial melting event in the mantle prior to the construction of the Vizcaino intra-oceanic arc, which is probably related to the Permian continental subduction, dated at ~ 311 Ma.
DS201907-1565
2019
Talavera, C.Oliveira, E.P., Talavera, C., Windley, B.F., Zhao, L., Semprich, J.J., McNaughton, N.J., Amaral, W.S., Sombini, G., Navarro, M., Silva, D.Mesoarchean ( 2820 Ma )high pressure mafic granulite at Uaus, Sao Francisco craton, Brazil, and its potential significance for the assembly of Archean supercraton.Precambrian Research, Vol. 331, 105266 20p.South America, Brazilcraton
DS1989-1477
1989
Talbot, C.J.Talbot, C.J., Von Brunn, V.Melanges, intrusive and extrusive sediments and hydraulic arcsGeology, Vol. 17, No. 5, May pp. 446-448South AfricaMelanges
DS1995-1866
1995
Talbot, L.W.Talbot, L.W.Due diligence in mining property acquisitionMining and the Environment: regulation and liability, 25pCanadaOre reserves, Economics
DS201412-0855
2014
Talgamer, B.L.Snetkov, V.I., Talgamer, B.L.Appraisal and exploitation of mining and dressing waste at dredge sites. Journal of Mining Science, Vol. 50, 1, pp. 108-114.Russia, TransbaikaliaDiamond alluvials
DS201412-0856
2014
Talgamer, B.L.Snetkov, V.I., Talgamer, B.L.Appraisal and exploitation of mining and dressing waste at dredge sites. ( Mainly gold but diamonds as well).Journal of Mining Science, Vol. 50, 1, pp. 108-114.RussiaDredging
DS200712-1064
2007
Talibova, A.G.Talibova,A.G., Ponomarchuk, V.A., Semenova, D.V.EA-IRMS: analysis of graphite and diamond.Plates, Plumes, and Paradigms, 1p. abstract p. A997.TechnologyDiamond
DS200612-0174
2006
Taliere, S.Brodhag, C., Taliere, S.Sustainable development strategies: tools for policy coherence.Natural Resources Forum, Vol. 30, 2, May pp. 136-145.GlobalEnvironment
DS1930-0229
1936
Taljaard, M.S.Taljaard, M.S.South African Melilite Basalts and their RelationsGeological Society of South Africa Transactions, Vol. 39, PP. 281-316.South AfricaUltrabasic Related Rocks
DS1930-0230
1936
Taljaard, M.S.Taljaard, M.S.Reply to a Discussion of His Paper "south African Melilite Basalts and Their Relations".Geological Society of South Africa Proceedings, Vol. 39, PP. 96-97.South AfricaUltrabasic Related Rocks
DS200612-1508
2005
Tallaire, A.Wang, W., Tallaire, A., Hall, M.S., Moses, T.M., Achard, J., Sussmans, R.S., Gicquel, A.Experimental CVD synthetic diamonds form LIMPH-CNRD France.Gems & Gemology, Vol. 41, 3, Fall, pp. 234244.TechnologySynthetic diamonds
DS201112-1026
2011
Tallaire, A.Tallaire, A., Barjon, J., Brinza, O., Achard, Silva, Mille, Issaoui, Tardieu, GicquelDislocations and impurities introduced from etch-pitts at the epitaxial growth resumption of diamond.Diamond and Related Materials, Vol. 20, 7, pp. 875-881.TechnologyDiamond morphology
DS201112-1115
2011
Tallaire, A.Willems, B., Tallaire, A., Barjon, J.Exploring the origin and nature of luminescent regions in CVD synthetic diamond.Gems & Gemology, Vol. 47, 3, fall pp. 202-207.TechnologySynthetic diamond
DS201201-0860
2011
Tallaire, A.Willems, B., Tallaire, A., Barjon, J.Exploring the origin and nature of luminscent regions in CVD synthetic diamonds.Gems & Gemology, Vol. 47, 3, pp. 202-207.TechnologySpectroscopy - synthetics
DS201212-0780
2011
Tallaire, A.Willems, B., Tallaire, A., Barjon, J.Exploring the origin and nature of luminescent regions in CVD synthetic diamond.Gems & Gemology, Vol. 47, 3, Fall, pp.TechnologySynthetics
DS201112-0911
2011
Tallarico, A.Santini, S., Tallarico, A., Dragoni, M.Magma ascent and effusion from a tensile fracture propogating to the Earth's urface.Geophysical Journal International, in press available,MantleMineral physics, rheology, heat flow, plumes
DS1991-1688
1991
Tallarico, F.H.B.Tallarico, F.H.B., Souza, J.C.F., Leonardos, O.H., Meyer, H.O.A.The Mat a Do Lenco mica-rich kimberlite, western Minas GeraisProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 408-409BrazilMacrocrysts, Mineral chemistry
DS1993-1569
1993
Tallarico, F.H.B.Tallarico, F.H.B., Leonardos, O.H., Gibson, S.A., Meyer, H.O.A.Quimica mineral da intrusa o da mat a do lenco, Abadia dos Dourados, MinasGerais.(in Portugese).Brasiliao Geologi do Diamante UFMT., Esp. 2/93, Cuabe, pp. 114-128.BrazilDa Mata do Lenco, Kimberlitic intrusive
DS1995-1867
1995
Tallarico, F.H.B.Tallarico, F.H.B., Leonardos, O.H.Glimeritic and peridotitic xenoliths from the Mat a do Lenco micaceous kimberlite -Alto Paranaiba-MetasomatismProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 600-602.Brazil, Alto ParanaibaXenoliths, Deposit -Mato do Lenco
DS1988-0290
1988
Talma, S.Harmer, R.D., Talma, S.Isotope geochemistry of mid-Proterozoic carbonatite complexes from SouthAfrica: implications for the composition of the Proterozoic sub-continentalmantleV.m. Goldschmidt Conference, Program And Abstract Volume, Held May, p. 46. AbstractSouth AfricaBlank
DS1990-0161
1990
Talnikov, S.B.Barashkov, I.P., Matsiuk, S.S., Talnikov, S.B.First find of zonal bi-refringence garnets from the Udachnaya kimberlitepipe, Yakutia. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 314, No. 3, pp. 698-701RussiaGarnet mineralogy, Deposit -Udachnaya
DS1988-0008
1988
Talnikova, S.B.Altukhova, Z.A., Talnikova, S.B.Typomorphic indications of hydrothermal haloes Of kimberlite pipes in carbonate country rocks.(Russian)Topomineral. I Tipomorfizm. Mineralov. Yakutsk.(Russian), pp. 36-43RussiaAlteration, metamorphism
DS1990-0115
1990
Talnikova, S.B.Altukhova, Z.A., Talnikova, S.B.Rare earth elements in autolith-bearing kimberlite breccias as indicators of geochemical evolution of the kimberlite systemInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 780-781RussiaGeochemistry, Kimberlite -rare earths
DS1990-1442
1990
Talnikova, S.B.Talnikova, S.B., Spetsius, Z.V., Pavlova, L.A.Characteristics of the phase composition of sulfide inclusions in garnets from the Udachnaya kimberlite pipe. (Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 6, pp. 44-51Russia, YakutiaDiamond inclusions, Garnets
DS1991-1689
1991
Talnikova, S.B.Talnikova, S.B., Barashkov, Y.P., Svoren, I.M.Gas-composition and content in eclogitic and ultrabasic diamonds From kimberlite pipes of Yakutia.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 321, No. 1, pp. 194-197. # HB124Russia, YakutiaEclogites, Diamonds, geochemistry
DS1991-1690
1991
Talnikova, S.B.Talnikova, S.B., Barashkov, Yu.P., Svoren, I.M.Study of gaseous phase in diamonds with eclogitic and ultrabasic inclusions from Yakutian kimberlite pipesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 565-566RussiaDiamond inclusions, Deposit -Udachnaya
DS1992-0081
1992
Talnikova, S.B.Barashkov, Yu.P., Matsyuk, S.S., Talnikova, S.B.First find of garnet with zoned birefringence in material from the Udachnaya kimberlite pipe, YakutiaDoklady Academy of Sciences USSR, Earth Science Section, Vol. 314, No. 1-6, July 1992, pp. 198-200Russia, YakutiaGarnet, Mineralogy
DS1993-1570
1993
Talnikova, S.B.Talnikova, S.B., avlova, L.A.Mineralogy of inclusions in diamond crystals of cubic habitRussian Geology and Geophysics, Vol. 34, No. 7, pp. 89-96.RussiaDiamond morphology, Mineralogy -inclusions
DS1994-1741
1994
Talnikova, S.B.Talnikova, S.B., Barashkov, Yu.P., Svoren, I.M.Composition and concentration of gases in diamonds of eclogite ultramafic parageneses in kimberlite pipes.Doklady Academy of Sciences USSR, Earth Science Section, Vol. 322, No. 1, pp. 157-160.Russia, YakutiaDiamond inclusions, Eclogites
DS1995-1868
1995
Talnikova, S.B.Talnikova, S.B.Inclusions in natural diamonds of different habitsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 603-605.Russia, YakutiaDiamond morphology, Deposit -Udachnaya
DS1996-0074
1996
Talnikova, S.B.Barashkov, Yu.P., Talnikova, S.B.Sulfide inclusions in diamonds and kimberlite minerals; similarities and differences (Udachnaya pipe).Russian Geology and Geophysics, Vol. 37, No. 6, pp. 42-53.Russia, YakutiaDiamond inclusions, geochemistry, Deposit - Udachnaya
DS1997-0075
1997
Talnikova, S.B.Barashkov, Yu.P., Griffin, W.L., Talnikova, S.B.Trace elements in sulfide inclusions in olivine from the Udachnaya kimberlite pipe, Yakutia.Geochemistry International, Vol. 35, No. 7, July, pp. 676-680.Russia, YakutiaInclusions - sulfide, olivine, Deposit - Udachnaya
DS1998-0075
1998
Talnikova, S.B.Barashkov, Y.P., Talnikova, S.B.The features of the morphology crystalline inclusions and the real structure of diamonds.7th International Kimberlite Conference Abstract, pp. 40-42.RussiaDiamond morphology
DS201212-0645
2012
Talsma, A.S.Shephard, G.E., Bunge, H-P., Schuberth, B.S.A., Muller, R.D., Talsma, A.S., Moder, C., Landgrebe, T.C.W.Testing absolute plate reference frames and the implications for the generation of geodynamic mantle heterogeneity stucture.Earth and Planetary Science Letters, Vol. 317-318, pp. 204-217.MantleGeodynamics
DS201412-0087
2014
Talsma, A.S.Butterworth, N.P., Talsma, A.S., Muller, R.D., Seton, M., Bunge, H-P., Schuberth, B.S.A., Shephard, G.E., Heine, C.Geological, tomographic, kinematic and geodynamic constraints on the dynamics of sinking slabs.Journal of Geodynamics, Vol. 73, pp. 1-13.MantleSubduction
DS201312-0116
2013
Talsman, A.S.Butterworth, N.P., Talsman, A.S., Muller, R.D., Seton, M., Bunge, H-P., Schuberth, B.S.A., Shephard, G.E., Heine, C.Geological, tomographic, kinematic and geodynamic constraints on the dynamics of sinking slabs.Earth Science Reviews, Vol. 126, pp. 235-249.MantleSubduction
DS201412-0116
2014
Talukdar, D.Chalapathi Rao, N.V., Kumar, A., Sahoo, S., Dongre, A.N., Talukdar, D.Petrology and petrogenesis of Mesoproterozoic lamproites from the Ramadugu field NW margin of the Cuddapah basin, eastern Dharwar craton, southern India.Lithos, Vol. 196-197, pp. 150-168.IndiaLamproite
DS201809-2098
2018
Talukdar, D.Talukdar, D., Pandey, A., Chalapathi Rao, N.V., Kumar, A., Pandit, D., Belyatsky, B.Petrology and geochemistry of the Mesoproterozoic Vattikod lamproites, eastern Dharwar craton, southern India: evidence for multiple enrichment of sub-continental lithospheric mantle and links with amalgamation and break up of the Columbia supercontinent.Contributions to Mineralogy and Petrology, Vol. 173, doi.org/10.1007/ s00410-018-1493-y 27p.Indialamproites

Abstract: Numerous lamproite dykes are hosted by the Eastern Dharwar Craton, southern India, particularly towards the northwestern margin of the Cuddapah Basin. We present here a comprehensive mineralogical and geochemical (including Sr and Nd isotopic) study on the lamproites from the Vattikod Field, exposed in the vicinity of the well-studied Ramadugu lamproite field. The Vattikod lamproites trend WNW-ESE to NW-SE and reveal effects of low-temperature post-magmatic alteration. The studied lamproites show porphyritic texture with carbonated and serpentinized olivine, diopside, fluorine-rich phlogopite, amphibole, apatite, chromite, allanite, and calcite. The trace-element geochemistry (elevated Sr and HFSE) reveals their mixed affinity to orogenic as well as anorogenic lamproites. Higher fluorine content of the hydrous phases coupled with higher whole-rock K2O highlights the role of metasomatic phlogopite and apatite in the mantle source regions. Trace-element ratios such as Zr/Hf and Ti/Eu reveal carbonate metasomatism of mantle previously enriched by ancient subduction processes. The initial 87Sr/86Sr-isotopic ratios (calculated for an assumed emplacement age of 1350 Ma) vary from 0.7037 to 0.7087 and ?Nd range from -?10.6 to -?9.3, consistent with data on global lamproites and ultrapotassic rocks. We attribute the mixed orogenic-anorogenic character for the lamproites under study to multi-stage metasomatism. We relate the (1) earlier subduction-related enrichment to the Paleoproterozoic amalgamation of the Columbia supercontinent and the (2) second episode of carbonate metasomatism to the Mesoproterozoic rift-related asthenospheric upwelling associated with the Columbia breakup. This study highlights the association of lamproites with supercontinent amalgamation and fragmentation in the Earth history.
DS1975-0373
1976
Talvitie, J.Paarma, H., Talvitie, J.Deep Fractures in the Sokli CarbonatiteContrib. Department Geophysics, University Oulu, No. 65, PP. 1-5.Norway, ScandinaviaStructure
DS201603-0366
2016
Tamarova, A.Bindi, L., Tamarova, A., Bobrov, A.V., Sirotkina, E.A., Tschauner, O., Walter, M.J., Irifune, T.in corporation of high amounts of Na in ringwoodite: possible implications for transport of alkali into lower mantle.American Mineralogist, Vol. 101, pp. 483-486.MantleRingwoodite
DS201711-2529
2017
Tamarova, A.P.Tamarova, A.P., Bobrov, A.V., Sirotkina, E.A., Bindi, L., Irifune, T.Melting of model pyrolite under the conditions of the transition zone.Proceedings of XXXIV held Aug. 4-9. Perchuk International School of Earth Sciences, At Miass, Russia, 1p. AbstractMantlemelting
DS201809-1996
2018
Tamarova, A.P.Bobrov, A.V., Tamarova, A.P., Sirotkina, E.A., Zhang, G.S., Irifune, T.Interphase partitioning of minor elements in the transition zone and uppermost lower mantle.Goldschmidt Conference, 1p. AbstractMantlediamond inclusions

Abstract: Interphase partitioning of minor elements was studied experimentally upon partial melting of model pyrolite [1] with addition of 2 wt % H2O, 10, and 15 wt % of multicomponent carbonate at 22-24 GPa and 1300-2200°C. The concentrations of minor elements were analyzed on an Agilent 7500a mass spectrometer. Phase associations included quenched melt (L), bridgmanite (Brd), CaSiO3- perovskite (CaPrv), ringwoodite (Rwd), ferropericlase (Fp), and majoritic garnet (Maj). The sequence of phase assemblages in our runs is consistent to that reported in [2] for melting of anhydrous pyrolite at 24 GPa: Fp+L, Fp+Maj+Brd(Rwd)+L, Fp+Maj+Brd(Rwd)+CaPrv. Most of minor elements, except for Sc, Cr, and Ni, are incompatible for Brd and show slight increase in partitioning coefficients from LREEs to HREEs in the H2O-bearing system. Pyrolite with carbonate is characterized by slightly higher LREE partitioning coefficients. Monovalent elements (Li, K, Cs, Rb), as well as Sr and Pb, are strongly incompatible for Brd in all systems. The similar features are observed for Fp enriched in HREEs and depleted in LREEs; all minor elements show redistribution into Fp with pressure. CaPrv is enriched in LREEs and depleted in HREEs. We applied the lattice strain model [3] for interpretation of the analytical data, which allowed us to study the behavior of minor elements as a function of P-T parameters. Our data and some previous results [4] were used for estimation of the composition of melts in equilibrium with inclusions in diamonds from the transition zone and lower mantle.
DS202004-0537
2020
Tamarova, A.P.Tamarova, A.P., Marchenko, E.I., Bobrov, A.V., Eremin, N.N., Zinovera, N.G., Irifune, T., Hirata, T., Makino, Y.Interphase REE partitioning at the boundary between the Earth's transition zone and lower mantle: evidence from experiments and atomistic modeling.Minerals MDPI, Vol. 10, 10030262 14p. PdfMantleREE

Abstract: Trace elements play a significant role in interpretation of different processes in the deep Earth. However, the systematics of interphase rare-earth element (REE) partitioning under the conditions of the uppermost lower mantle are poorly understood. We performed high-pressure experiments to study the phase relations in key solid-phase reactions CaMgSi2O6 = CaSiO3-perovskite + MgSiO3-bridgmanite and (Mg,Fe)2SiO4-ringwoodite = (Mg,Fe)SiO3-bridgmanite + (Mg,Fe)O with addition of 1 wt % of REE oxides. Atomistic modeling was used to obtain more accurate quantitative estimates of the interphase REE partitioning and displayed the ideal model for the high-pressure minerals. HREE (Er, Tm, Yb, and Lu) are mostly accumulated in bridgmanite, while LREE are predominantly redistributed into CaSiO3. On the basis of the results of experiments and atomistic modeling, REE in bridgmanite are clearly divided into two groups (from La to Gd and from Gd to Lu). Interphase REE partition coefficients in solid-state reactions were calculated at 21.5 and 24 GPa for the first time. The new data are applicable for interpretation of the trace-element composition of the lower mantle inclusions in natural diamonds from kimberlite; the experimentally determined effect of pressure on the interphase (bridgmanite/CaSiO3-perovskite) REE partition coefficients can be a potential qualitative geobarometer for mineral inclusions in super-deep diamonds.
DS202010-1830
2020
Tamblyn, R.Brown, D.A., Tamblyn, R., Hand, M., Morrissey, L.J.Thermobarometric constraints on burial and exhumation of 2 billion year old eclogites and their metapelitic hosts.Precambrian Research, Vol. 347, 105833, 33p. PdfAfrica, Tanzaniaeclogites

Abstract: One of the first appearances of eclogite-facies mineral assemblages in the geological record occurs in the c. 2000 Ma Palaeoproterozoic Usagaran Belt in central Tanzania, where the extended margin of the Tanzanian Craton is interpreted to have been subducted. Mafic rocks are interpreted to have contained the mineral assemblage garnet + omphacite + rutile + quartz ± amphibole. This high-pressure assemblage has been overprinted by a secondary mineral assemblage containing clinopyroxene + plagioclase + hornblende + ilmenite ± orthopyroxene. Mineral equilibria forward modelling indicates that the eclogite-facies assemblages reached minimum peak pressure-temperature (P-T) conditions of ~17 kbar and ~700 °C. Inclusions in garnet document a prograde P-T history consistent with burial through upper amphibolite-facies conditions and possible partial melting. Petrological and compositional evidence from garnet suggests that following peak metamorphism, the eclogite-facies rocks were heated while stalled at approximate peak pressures. Temperature estimates derived from Zr concentrations in interpreted texturally retrograde rutile support a near-isothermal post-peak P-T evolution for the eclogite-facies rocks - an evolution that terminates at retrograde P-T conditions of approximately 7.6-8.2 kbar and 680-790 °C. The relict eclogite domains form part of a larger assemblage with enclosing migmatitic metapelitic lithologies (the Isimani Suite). The metapelitic gneisses contain garnet + kyanite + biotite + staurolite + hornblende + plagioclase + muscovite + rutile + quartz and preserve minimal evidence of a high-pressure history, conceivably due to post-peak mineralogical recrystallisation. P-T modelling, inclusion assemblages and compositional zonation patterns in porphyroblastic garnet suggests the metapelitic gneisses — similarly to the relict eclogites — experienced burial to minimum peak pressures of approximately 16.5-17 kbar. Compositional zoning patterns in eclogitic garnet suggest the Isimani system was buried, reached peak metamorphic conditions, and was subsequently exhumed within a timeframe of up to 20 Myr. A tectonic regime involving crustal thickening and subduction, followed by extensional exhumation of the entire Isimani Suite is our preferred model for the development of the c. 2000 Ma Usagaran Belt.
DS201801-0064
2017
Tamech, L.S.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.
DS201412-0910
2015
Tamen, J.Tamen, J., Nkoumbou, C., Reuesser, E., Tchouda, F.Petrology and geochemistry of mantle xenoliths from Kapsiki Plateau ( Cameroon Volcanic Line): implications for lithospheric upwelling.Journal of African Earth Sciences, Vol. 101, pp. 119-134.Africa, CameroonXenoliths
DS201502-0112
2015
Tamen, J.Tamen, J., Nkoumbou, C., Reusser, E., Tchoua, F.Petrology and geochemistry of mantle xenoliths from the Kapsiki Plateau ( Cameroon Volcanic Line): implications for lithospheric upwelling.Journal of African Earth Sciences, Vol. 101, pp. 119-134.Africa, CameroonMetasomatism
DS200712-1065
2007
TamisieaTamisieaIce, the mantle and Canadian gravity lows.Science, Vol. 316, 5826 May 11, p. 881-Canada, Northwest TerritoriesGeophysics - gravity
DS200612-0497
2006
Tamrat, E.Gregory, L.C., Meert, J.G., Pradhan, V., Pandit, M.K., Tamrat, E., Malone, S.J.A paleomagnetic and geochronologic study of the Majhgawan kimberlite. India: implications for the age of the Upper Vindhyan Supergroup.Precambrian Research, Vol. 149, 1-2, pp. 65-75.IndiaDeposit - Majhgawan, geophysics, geochronology
DS201012-0608
2010
Tamura, A.Rajesh, V.J., Arai, S., Santosh, M., Tamura, A.LREE rich hibonite in ultrapotassic rocks in southern India.Lithos, Available in press formated 11p.IndiaAlkalic
DS201710-2270
2017
Tamura, A.Umino, S., Knayama, K., Kitamura, K., Tamura, A., Ishizuka, A., Senda, R., Arai, S.Did boninite originate from the heterogeneous mantle with reycled ancient slab?Island Arc, Sept. 28, 3p.Mantlesubduction

Abstract: Boninites are widely distributed along the western margin of the Pacific Plate extruded during the incipient stage of the subduction zone development in the early Paleogene period. This paper discusses the genetic relationships of boninite and antecedent protoarc basalt magmas and demonstrates their recycled ancient slab origin based on the T-P conditions and Pb-Hf-Nd-Os isotopic modeling. Primitive melt inclusions in chrome spinel from Ogasawara and Guam islands show severely depleted high-SiO2, MgO (high-silica) and less depleted low-SiO2, MgO (low-silica and ultralow-silica) boninitic compositions. The genetic conditions of 1?346?°C at 0.58?GPa and 1?292?°C at 0.69?GPa for the low- and ultralow-silica boninite magmas lie on adiabatic melting paths of depleted mid-ocean ridge basalt mantle with a potential temperature of 1?430?°C in Ogasawara and of 1?370?°C in Guam, respectively. This is consistent with the model that the low- and ultralow-silica boninites were produced by remelting of the residue of the protoarc basalt during the forearc spreading immediately following the subduction initiation. In contrast, the genetic conditions of 1?428?°C and 0.96?GPa for the high-silica boninite magma is reconciled with the ascent of more depleted harzburgitic source which pre-existed below the Izu-Ogasawara-Mariana forearc region before the subduction started. Mixing calculations based on the Pb-Nd-Hf isotopic data for the Mariana protoarc basalt and boninites support the above remelting model for the (ultra)low-silica boninite and the discrete harzburgite source for the high-silica boninite. Yb-Os isotopic modeling of the high-Si boninite source indicates 18-30?wt% melting of the primitive upper mantle at 1.5-1.7?Ga, whereas the source mantle of the protoarc basalt, the residue of which became the source of the (ultra)low-Si boninite, experienced only 3.5-4.0?wt% melt depletion at 3.6-3.1?Ga, much earlier than the average depleted mid-ocean ridge basalt mantle with similar degrees of melt depletion at 2.6-2.2?Ga.
DS201810-2326
2018
Tamura, A.Guotana, J.M., Morishita, T., Yamaguchi, R., Nishio, I., Tamura, A., Tani, K., Harigane, Y., Szilas, K., Pearson, D.G.Contrasting textural and chemical signatures of chromitites in the Mesoarchean Ulamertoq peridotite body, southern West Greenland.MDPI Geosciences, Researchgate 19p.Europe, Greenlandperidotite

Abstract: Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting metamorphic textural and chemical features. Chromitite layers from different localities in Ulamertoq show contrasting characteristics. In one locality, zoned chromites are hosted in orthopyroxene-amphibole peridotites. Compositional zonation in chromites is evident with decreasing Cr and Fe content from core to rim, while Al and Mg increase. Homogeneous chromites from another locality are fairly uniform and Fe-rich. The mineral chemistry of the major and accessory phases shows metamorphic signatures. Inferred temperature conditions suggest that the zoned chromites, homogeneous chromites, and their hosts are equilibrated at different metamorphic conditions. In this paper, various mechanisms during the cumulus to subsolidus stages are explored in order to understand the origin of the two contrasting types of chromites.
DS201811-2575
2018
Tamura, A.Guotana, J.M., Morishita, T., Yamaguchi, R., Nishio, I., Tamura, A., Harigane, Y., Szilas, K., Pearson, G.Contrasting textural and chemical signatures of chromitites in the Mesoarchean Ulamertoq peridotite body, southern West Greenland.Geosciences, Vol. 8, no. 9, p. 328-Europe, Greenlandperidotite

Abstract: Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting metamorphic textural and chemical features. Chromitite layers from different localities in Ulamertoq show contrasting characteristics. In one locality, zoned chromites are hosted in orthopyroxene-amphibole peridotites. Compositional zonation in chromites is evident with decreasing Cr and Fe content from core to rim, while Al and Mg increase. Homogeneous chromites from another locality are fairly uniform and Fe-rich. The mineral chemistry of the major and accessory phases shows metamorphic signatures. Inferred temperature conditions suggest that the zoned chromites, homogeneous chromites, and their hosts are equilibrated at different metamorphic conditions. In this paper, various mechanisms during the cumulus to subsolidus stages are explored in order to understand the origin of the two contrasting types of chromites.
DS201905-1037
2019
Tamura, A.Guotana, J.M., Morishita, T., Yamaguschi, R., Nishio, I., Tamura, A., Tani, K., Harigane, Y., Szilas, K., Pearson, D.G.Contrasting textural and chemical signatures of chromitites in the Mesoarchean Ulamertoq peridotite body, southern west Greenland.Geosciences ( MDPI), Vol. 8, 328- 19p.Europe, Greenlandchromitite

Abstract: Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting metamorphic textural and chemical features. Chromitite layers from different localities in Ulamertoq show contrasting characteristics. In one locality, zoned chromites are hosted in orthopyroxene-amphibole peridotites. Compositional zonation in chromites is evident with decreasing Cr and Fe content from core to rim, while Al and Mg increase. Homogeneous chromites from another locality are fairly uniform and Fe-rich. The mineral chemistry of the major and accessory phases shows metamorphic signatures. Inferred temperature conditions suggest that the zoned chromites, homogeneous chromites, and their hosts are equilibrated at different metamorphic conditions. In this paper, various mechanisms during the cumulus to subsolidus stages are explored in order to understand the origin of the two contrasting types of chromites.
DS201905-1064
2019
Tamura, A.Nishio, I., Morishita, T., Szilas, K., Pearson, G., Tani, K-I., Tamura, A., Harigane, Y., Guotana, J.M.Titanium clinohumite bearing peridotite from the Ulamertoq ultramafic body in the 3.0 Ga Akia terrane of southern west Greenland.Geosciences ( MDPI), 20p. Europe, Greenlandperidotite

Abstract: A titanian clinohumite-bearing dunite was recently found in the Ulamertoq ultramafic body within the 3.0 Ga Akia Terrane of southern West Greenland. Titanian clinohumite occurs as disseminated and discrete grains. Titanian clinohumite contains relatively high amounts of fluorine, reaching up to 2.4 wt.%. The high-Fo content of olivine (Fo93) coupled with low Cr/(Cr + Al) ratio of orthopyroxene implies that the dunite host is not of residual origin after melt extraction by partial melting of the primitive mantle. Olivine grains are classified into two types based on abundances of opaque mineral inclusions: (1) dusty inclusion-rich and (2) clear inclusion-free olivines. Opaque inclusions in coarse-grained olivines are mainly magnetite. Small amounts of ilmenite are also present around titanian clinohumite grains. The observed mineral association indicates partial replacement of titanian clinohumite to ilmenite (+magnetite) and olivine following the reaction: titanian clinohumite = ilmenite + olivine + hydrous fluid. The coexistence of F-bearing titanian clinohumite, olivine, and chromian chlorite indicates equilibration at around 800-900 °C under garnet-free conditions (<2 GPa). Petrological and mineralogical characteristics of the studied titanian clinohumite-bearing dunite are comparable to deserpentinized peridotites derived from former serpentinites. This study demonstrates the importance of considering the effects of hydration/dehydration processes for the origin of ultramafic bodies found in polymetamorphic Archaean terranes.
DS201808-1790
2017
Tamura, N.Stan, C.V., Obannon, E.F., Dobrzhinetskaya, L.F., Tamura, N.Polytypism in natural SiC using Laue microdiffraction.Acta Crystallographia, A70, 1p. abstractEurope, Israelmoissanite

Abstract: Silicon carbide (SiC, moissanite) is a common industrial material that is rarely found in terrestrial rocks and meteorites. It has been found to adopt over 300 different crystal structures, most of which are polytypic: they consist of alternating layers of Si and C, with only small stacking faults or shears distinguishing them from one another. In nature, only a few polytypes of SiC have been found, primarily a cubic zincblende type (3C-SiC), several hexagonal wurtzite types (4H-SiC and 6H-SiC), and a rhombohedral type (15R-SiC). Our natural silicon carbide sample is from a Miocene tuff (Yizre’el Valley, Israel) related to interplate alkaline basalt volcanism. Three SiC grains with native silicon and metal silicide inclusions were analyzed using Raman spectroscopy and synchrotron Laue X-ray microdiffraction accompanied by mapping at a 5-8 um resolution. SiC is found to crystallize in only the 4H and 6H polytypes. Due to the crystal orientation of the grains, as well as the significant difference in the c-axis length (~10 vs. ~15 um in 4H and 6H respectively), we were able to unambiguously assign polytypes to each diffraction pattern. Each grain contains large areas where one polytype dominates as a single crystal. In some cases, multiple stacking faults and misoriented polycrystalline aggregates of SiC occur at the 4H/6H interface. In other cases we see intercalation of the 4H and 6H crystals throughout the diffracting volume without a significant change in their crystallographic axes orientation, pointing to a possibly incommensurate crystal structure. Stress and strain are also mapped for all three grains, showing a slight (< 2 ppt) compressive strain in the y direction of all three grains, and a tensile strain in the x and z directions. In the SiC-2 grain, a mostly single-crystalline Si inclusion was found, with an exposed surface diameter of ~30 um. We examine residual strain in Si by both Laue X-ray diffraction and Raman spectroscopy, and find results to generally agree between the two measurements.
DS202004-0535
2020
Tamura, N.Stan, C.V., O'Bannon III, E.F., Mukhin, P., Tamura, N., Dobrzhinetskaya, L.X-ray laue microdiffraction and raman spectroscopic investigation of natural silicon and moissanite.Minerals MDPI, Vol. 10, 10030204 12p. PdfGlobalmoissanite

Abstract: Moissanite, SiC, is an uncommon accessory mineral that forms under low oxygen fugacity. Here, we analyze natural SiC from a Miocene tuff-sandstone using synchrotron Laue microdiffraction and Raman spectroscopy, in order to better understand the SiC phases and formation physics. The studied crystals of SiC consist of 4H- and 6H-SiC domains, formed from either, continuous growth or, in one case, intergrown, together with native Si. The native Si is polycrystalline, with a large crystal size relative to the analytical beam dimensions (>1-2 µm). We find that the intergrown region shows low distortion or dislocation density in SiC, but these features are comparatively high in Si. The distortion/deformation observed in Si may have been caused by a mismatch in the coefficients of thermal expansion of the two materials. Raman spectroscopic measurements are discussed in combination with our Laue microdiffraction results. Our results suggest that these SiC grains likely grew from an igneous melt.
DS2002-1576
2002
Tamura, Y.Tamura, Y., Tatsumi, Y., Zhao, D., Kido, Y., Sukuno, H.Hot fingers in the mantle wedge: new insights into magma genesis in subduction zonesEarth and Planetary Science Letters, Vol.197,1-2,pp.105-116.MantleSubduction, tomography, geophysics - seismics
DS1986-0119
1986
TanCai Xiucheng, Guo Jiugao, Chen Feng, Fu Yude, Tang Rongbing, TanDistribution of paramagnetic nitrogen in placer diamonds with specialAcad. Sin. Institute Geochem., Guiyang, *CHI, Vol. 6, No. 3, September pp. 195-202ChinaAlluvials, Geochemistry, diamond inclusions
DS1986-0120
1986
TanCai Xiucheng, Guo Jiugao, Chen, Feng, Fu, Yude, Tang Rongbing, TanDistribution of paramagnetic nitrogen in placer diamonds with Special reference to its significance in diamond classification. *CHIKuangwu Xuebao, *CHI, Vol. 6, No. 3, pp. 195-202ChinaAlluvials, Diamond inclusions-nitrog
DS201901-0017
2018
Tan, D.Chen, M., Shu, J., Xie, X., Tan, D.Maohokite, a post-spinel polymorph of MgFe2O4 in shocked gneiss from the Xiuyan crater in China.Meteoritics & Planetary Science, doi.10.1111/ maps.13222 8p.Chinamineralogy

Abstract: Maohokite, a post-spinel polymorph of MgFe2O4, was found in shocked gneiss from the Xiuyan crater in China. Maohokite in shocked gneiss coexists with diamond, reidite, TiO2-II, as well as diaplectic glasses of quartz and feldspar. Maohokite occurs as nano-sized crystallites. The empirical formula is (Mg0.62Fe0.35Mn0.03)2+Fe3+2O4. In situ synchrotron X-ray microdiffraction established maohokite to be orthorhombic with the CaFe2O4-type structure. The cell parameters are a = 8.907 (1) Å, b = 9.937(8) Å, c = 2.981(1) Å; V = 263.8 (3) Å3; space group Pnma. The calculated density of maohokite is 5.33 g cm-3. Maohokite was formed from subsolidus decomposition of ankerite Ca(Fe2+,Mg)(CO3)2 via a self-oxidation-reduction reaction at impact pressure and temperature of 25-45 GPa and 800-900 °C. The formation of maohokite provides a unique example for decomposition of Fe-Mg carbonate under shock-induced high pressure and high temperature. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2017-047). The mineral was named maohokite after Hokwang Mao, a staff scientist at the Geophysical Laboratory, Carnegie Institution of Washington, for his great contribution to high pressure research.
DS200612-1407
2005
Tan, E.Tan, E., Gurnis, M.Metastable superplumes and mantle compressibility.Geophysical Research Letters, Vol. 32, 20, Oct. 28, L20307MantlePlume, hotspots
DS200712-1051
2007
Tan, E.Sun, D., Tan, E., Helmberger, D., Gurnis, M.Seismological support for the metastable superplume model, sharp features, and phase changes within the lower mantle.Proceedings of National Academy of Sciences USA, Vol. 104, 22, pp. 9151-9155. IngentaMantleGeophysics - seismics
DS200712-1066
2007
Tan, E.Tan, E., Gurnis, M.Compressible thermochemical convection and application to lower mantle structures.Journal of Geophysical Research, Vol. 112, B6, B06304.MantleGeothermometry
DS200912-0293
2009
Tan, E.Helmberger, D., Sun, D., Lui, L., Tan, E., Gurnis, M.Review of large low shear veolocity provinces in the lower mantle.Goldschmidt Conference 2009, p. A520 Abstract.MantleCMB
DS201312-0113
2013
Tan, E.Burstedde, C., Stadler,G., Alisic, L., Wilcox, L.C., Tan, E.,Gurnis, M., Ghattas, O.Large scale adaptive mantle convection simulation.Geophysical Journal International, Vol. 192, no. 3, pp. 889-906.MantleConvection
DS201604-0634
2016
Tan, J.S.Tan, J.S., Stachel, T., Morton, R.Diamonds from the Konawaruk River, Guyana.GAC MAC Meeting Special Session SS11: Cratons, kimberlites and diamonds., abstract 1/4p.South America, GuyanaKonawaruk area
DS201603-0379
2015
Tan, X.Goncharov, A.F., Lobanov, S.S., Tan, X., Hohensee, G.T., Cahill, D.G., Lin, J-F., Thomas, S-M., Okuchi, T., Tomioka, N., Helffrich, G.Experimental study of thermal conductvity at high pressures: implication for the deep Earth's interior.Physics of the Earth and Planetary Interiors, Vol. 247, pp. 11-16.MantleExperimental Petrology

Abstract: Lattice thermal conductivity of ferropericlase and radiative thermal conductivity of iron bearing magnesium silicate perovskite (bridgmanite) - the major mineral of Earth’s lower mantle- have been measured at room temperature up to 30 and 46 GPa, respectively, using time-domain thermoreflectance and optical spectroscopy techniques in diamond anvil cells. The results provide new constraints for the pressure dependencies of the thermal conductivities of Fe bearing minerals. The lattice thermal conductivity of ferropericlase Mg0.9Fe0.1O is 5.7(6) W/(m * K) at ambient conditions, which is almost 10 times smaller than that of pure MgO; however, it increases with pressure much faster (6.1(7)%/GPa vs 3.6(1)%/GPa). The radiative conductivity of a Mg0.94Fe0.06SiO3 bridgmanite single crystal agrees with previously determined values for powder samples at ambient pressure; it is almost pressure-independent in the investigated pressure range. Our results confirm the reduced radiative conductivity scenario for the Earth’s lower mantle, while the assessment of the heat flow through the core-mantle boundary still requires in situ measurements at the relevant pressure-temperature conditions.
DS1985-0660
1985
Tan qixinTan qixin, SUN YANLWANG ZHIXI, Liu qirong, LIU HONGSHU, Jiang yuchi.The Littoral Placer Deposits of China.*chiMarine Geol. and Quat. Geology, *CHI, Vol. 5, No. 4, pp. 41-47ChinaPlacers
DS1986-0317
1986
Tan Yi MeiGuo, Jiugao, Cai Xiucheng, Deng Huaxing, Chen Feng, Tan Yi MeiNatural type 1B diamonds in diamond placer in Hunan province. *CHIKexue Tongbao, *CHI, Vol. 31, No. 4, pp. 257-261ChinaDiamond morphology
DS2002-0013
2002
Tanaka, A.Akaogi, M., Tanaka, A., Ito, E.Garnet ilmenite perovskite transitions in the system ... at high pressures and high temperatures: phase equilibria, colorimetry and implications for mantle structurePhysics of the Earth and Planetary Interiors, Vol. 132, 4, pp. 303-24.MantleStructure - UHP
DS201112-0025
2011
Tanaka, C.Arai, S., Okamura, H., Kadoshima, K., Tanaka, C., Suzuki, K., Ishimaru, S.Chemical characteristics of chromian spinel in plutonic rocks: implications for deep magma processes and discrimination of tectonic setting.Island Arc, Vol. 20, 1, pp. 125-137.MantleMagmatism - tectonics
DS1993-0802
1993
Tanaka, H.Kepezhin, P.K., Taylor, R.N., Tanaka, H.Geochemistry of plutonic spinels from the north Kamchatka Arc - comparisons with spinels from other tectonic settings.Mineralogical Magazine, Vol. 57, No. 389, December pp. 575-589.RussiaGeochemistry
DS1993-0804
1993
Tanaka, H.Kepezhinskas, P.K., Reuber, I., Tanaka, H., Miyashitam S.Zoned calc alkaline plutons in northeastern Kamchatka, Russia: Implications for the crustal growth in magmatic arcs.Mineralogy and Petrology, Vol. 49, pp. 147-174.RussiaAlkaline rocks, Ultramafics -general not specific
DS1995-1869
1995
Tanaka, H.Tanaka, H., Kono, M., Uchimura, H.Some global features of palaeointensity in geological timeGeophys. Journal of International, Vol. 120, pp. 97-102GlobalVolcanics, Paleointensity database
DS200512-0934
2005
Tanaka, K.Santosj, M., Tanaka, K., Yokoyama, K., Collins, A.S.Late Neoproterozoic Cambrian felsic magmatism along transcrustral shear zones in southern India: U Pb electron microprobe ages implications for amalagamtionGondwana Research, Vol. 8, 1, pp. 31-42.IndiaGeochronology, Gondwana supercontinent
DS202007-1182
2020
Tanaka, R.Tanaka, R., Sakamaki, T., Ohtani, E., Fukui, H., Kamada, S., Suzuki, A., Tsutsui, S., Uchiyama, H., Baron, A.Q.R.The sound velocity of wustite at high pressures: implications for low-velocity anomalies at the base of the lower mantle.Progress in Earth and Planetary Science, Vol. 7, 23, 7p. PdfMantlewustite

Abstract: The longitudinal sound velocity (VP) and the density (?) of wüstite, FeO, were measured at pressures of up to 112.3?GPa and temperatures of up to 1700?K using both inelastic X-ray scattering and X-ray diffraction combined with a laser-heated diamond-anvil cell. The linear relationship between VP and ?, Birch’s law, for wüstite can be expressed as VP = 1.55 (1) × ? [g/cm3] - 2.03 (8) [km/s] at 300?K and VP = 1.61 (1) × ? [kg/m3] - 2.82 (10) [km/s] at 1700?K. The sound velocity of wüstite is significantly lower than that of bridgmanite and ferropericlase under lower mantle conditions. In other words, the existence of wüstite in the lower mantle can efficiently decrease the seismic velocity. Considering its slow velocity and several mechanisms for the formation of FeO-rich regions at the core-mantle boundary, we confirm earlier suggestions indicating that wüstite enrichment at the bottom of the Earth’s mantle may contribute to the formation of denser ultra-low velocity zones.
DS1992-1515
1992
Tanaka, S.Tanaka, S., Hamaguchi, H.Heterogeneity in the lower mantle beneath Africa, as revealed from S and ScS phasesTectonophysics, Vol. 209, pp. 213-222Southern AfricaMantle, Geophysics-gravity
DS2002-1577
2002
Tanaka, S.Tanaka, S.Very low shear wave velocity at the base of the mantle under the South Pacific Superswell.Earth and Planetary Science Letters, Vol. 203, 3-4, pp. 879-93.MantleGeophysics - seismics - not specific to diamonds
DS200612-1408
2005
Tanaka, S.Tanaka, S.Characteristics of PKP-Cdiff coda revealed by small aperture seismic arrays: implications for the study of the inner core boundary.Physics of the Earth and Planetary Interiors, Vol. 153, 1-3, pp. 49-60.MantleBoundary
DS201603-0424
2016
Tanaka, S.Tanaka, S., Aurnou, J., Bergman, M.Preface for the article collection of "multidisciplinary researchs on deep interiors of the Earth and planets.Progress in Earth and Planetary Science, Vol. 3, no. 6, 3p.MantleSEDI study
DS200512-1163
2005
Tanaka, T.Wallis, S., Tsuboi, M., Suzuki, K., Fanning, M., Jiang, L., Tanaka, T.Role of partial melting in the evolution of the Sulu (eastern China) ultrahigh pressure terrane.Geology, Vol. 33, 2, pp. 129-132.ChinaUHP
DS1992-1516
1992
Tanays, E.Tanays, E., Cojean, R., Hantz, D.DEGRES: a software to design open pit geometry and to draw open pit plansInternational Journal of Surface Mining and Reclamation, Vol. 6, pp. 91-98GlobalComputer, Program -DEGRES
DS1994-1164
1994
Tanczos, I.C.Meijer, de, R.J., Tanczos, I.C., Stapel, C.Radiometric techniques in heavy mineral exploration and exploitationExploration and Mining Geology, Vol. 3, No. 4, Oct. pp. 389-98GlobalHeavy sands, Radiometric mapping
DS1980-0327
1980
Tandon, G.L.Tandon, G.L.Diamond ProcessingTranscript of Paper From Diamond Seminar, Bombay, 13P.IndiaDiamond Recovery
DS1999-0726
1999
Tandon, K.Tandon, K., Brown., L., Hearn, T.Deep structure of the northern Rio Grande rift beneath the San Luis basin (Colorado) from a seismic surveyTectonophysics, Vol. 302, No. 1-2, Feb. 15, pp. 41-56.ColoradoTectonics, rift evolution
DS1991-0250
1991
Tane, J.L.Chabane, A., El Boukhari, A., Rocci, G., Tane, J.L.Discovery of Island Arc magmatics of boninitic affinity related to Pan-African ophiolite of Khzama(Siroua, Anti-Atlas, Morocco).(in French)Comptes Rendus de l'Academie des Sciences series II, (in French), Vol. 313, No. 11 November 21, pp. 1301-1304MoroccoOphiolites, Magma
DS1991-1143
1991
Taner, I.Meyerhoff, A.A., Kamen-Kaye, M., Chin Chen, Taner, I.Chin a -stratigraphy, paleogeography and tectonicsKluwer Publ, 188p. approx. $ 125.00ChinaTectonics, Stratigraphy
DS2001-0180
2001
TangChemenda, A.I., Hurpin, D., Tang, Stephan, BuffetImpact of arc continent collision on the conditions of burial and exhumation of UHP LT rocks.... experimentalTectonophysics, Vol. 342, No. 2, pp. 137-61.GlobalUHP, Tectonics
DS200812-1321
2008
TangZheng, J.P., Griffin, W.L., O'Reilly, S.Y., Hu, Zhang, Tang, Su, Zhang, Pearson, Wamg, Lu.Continental collision and accretion recorded in the deep lithosphere of central China.Earth and Planetary Science Letters, Vol. 269, 3-4 May 30, pp. 496-506.ChinaBasaltic diatremes, geochronology, craton, tectonics
DS200912-0859
2009
TangZheng, J., Griffin, W.L., O'Reilly, S.Y., Liu, G.L., Pearson, N., Zhang, W., Yu, C.M., Su, Tang, ZhaoNeoarchean ( 2.7-2.8 Ga) accretion beneath the North Chin a Craton: U Pn age.trace elemens and hf isotopes of zircons in Diamondiferous kimberlites.Lithos, Vol. 112, 3-4, pp. 188-202.ChinaGeochronology
DS200912-0860
2009
TangZheng, J.P., Griffin, W.L., O'Reilly, S.Y., Sun, M., Zheng, S., Pearson, N., Gao, Yu, Su, Tang, Liu, WuAge and composition of granulite and pyroxenite xenoliths in Hannuoba basalts reflect Paleogene underplating beneath the North Chin a craton.Chemical Geology, Vol. 264, 1-4, pp. 266-280.ChinaXenoliths
DS200912-0861
2009
TangZheng, J.P., Griffin, W.L., O'Reilly, S.Y., Zhao, J.H., Wu, Liu, Pearson, Zhang, Ma, Zhang, Yu, Su, TangNeoarchean ( 2.7-2.8 Ga) accretion beneath the North Chin a Craton: U Pb age, trace elements and Hf isotopes of zircons in Diamondiferous kimberlites.Lithos, Vol. 117, pp. 188-202.ChinaGeochronology
DS202001-0044
2019
Tang, F.Tang, F., Taylor, R.J.M., Einsle, J.F., Borlina, C.S., Fu, R.R., Weiss, B.P., Williams, H.M., Williams, W., Nagy, L., Midgley, P.A., Lima, E.A., Bell, E.A., Harrison, T.M., Alexander, E.W., Harrison, R.J.Secondary magnetite in ancient zircon precludes analysis of a Hadean geodynamo. Jack HillsProceedings National Academy of Science, Vol. 116, pp. 407-412.Australiapaleomagnetism

Abstract: Zircon crystals from the Jack Hills, Western Australia, are one of the few surviving mineralogical records of Earth’s first 500 million years and have been proposed to contain a paleomagnetic record of the Hadean geodynamo. A prerequisite for the preservation of Hadean magnetization is the presence of primary magnetic inclusions within pristine igneous zircon. To date no images of the magnetic recorders within ancient zircon have been presented. Here we use high-resolution transmission electron microscopy to demonstrate that all observed inclusions are secondary features formed via two distinct mechanisms. Magnetite is produced via a pipe-diffusion mechanism whereby iron diffuses into radiation-damaged zircon along the cores of dislocations and is precipitated inside nanopores and also during low-temperature recrystallization of radiation-damaged zircon in the presence of an aqueous fluid. Although these magnetites can be recognized as secondary using transmission electron microscopy, they otherwise occur in regions that are indistinguishable from pristine igneous zircon and carry remanent magnetization that postdates the crystallization age by at least several hundred million years. Without microscopic evidence ruling out secondary magnetite, the paleomagnetic case for a Hadean-Eoarchean geodynamo cannot yet been made.
DS201612-2316
2016
Tang, G.Li, Q., Li, X., Wu, F., Liu, Y., Tang, G.Accessory minerals SIMS U-Th-Pb dating for kimberlite and lamproite. Mengin, Shandong; Dahongshan, Hubei.Acta Geologica Sinica, Vol. 90, July abstract p. 74-75.ChinaPerovskite
DS201112-0594
2011
Tang, G-Q.Li, Q., Wu, F-Y., Li, X-H., Qiu, Z-L., Yang, Y-H., Tang, G-Q.Precisely dating Paleozoic kimberlites in the North Chin a craton and Hf isotopic constraints on the evolution of the subcontinental lithospheric mantle.Lithos, Vol. 126, pp. 127-134.ChinaMengyin, Fuxian
DS201112-0595
2011
Tang, G-Q.Li, Q-L., Wu, F-Y., Li, X-H., Qiu, Z-L., Liu, Y., Yang, Y-H., Tang, G-Q.Precise age determin ation of the Paleozoic kimberlites in North Chin a craton and Hf isotopic constraint on the evolution of its subcontinental lithospheric mantle.Goldschmidt Conference 2011, abstract p.1316.ChinaMengyin, Fuxian
DS201712-2683
2017
Tang, H.Deng, M., Xu, C., Song, W., Tang, H., Liu, Y., Zang, Q., Zhou, Y., Feng, M., Wei, C.REE mineralization in the Bayan Obo deposit, China: evidence from mineral paragenesis.Ore Geology Reviews, in press available, 10p.Chinadeposit - Bayan Obo

Abstract: Preliminary mineralogical and geochemical studies have been carried out on dolomite marble drill cores from the Bayan Obo REE deposit in China. Three types of apatites and four types of monazites have been identified based on textural features: Type 1 apatite occurs as grains with minor monazite (Type 1 monazite) on its border; Type 2 apatite veinlet shows clusters of assemblages with abundant bastnäsite and parisite at the rim; Type 3 apatite has a linear array associated with fluorite and bastnäsite veinlets. Type 2 monazite occurs as clusters intergrowing with parisite and fluorite. Type 3 and 4 monazites occur as polymineralic (fluorite and bastnäsite) and monomineralic veinlets, respectively. These four types of monazites have similar LREE composition but variable Y content (Y2O3 ranging from below determination limits to 0.7?wt%). The three types of apatites also show different REE content and distribution patterns, ranging from high REE abundance (?REE?+?Y: 27243-251789?ppm) and strong LREE enrichment [(La/Yb)CN ~101] in Type 1, less LREE enrichment [(La/Yb)CN ~8] in Type 2 to relatively low REE abundance (?REE?+?Y: 4323-11175?ppm) but high REE fractionation [(La/Yb)CN ~58] in Type 3. The primary apatite has high Sr (5461-6892?ppm) and REE content, implying a carbonatite origin. The late-stage apatites (Types 2 and 3) show different Sr and REE abundances. Significant differences in their Sr composition (6189?±?573, 6041?±?549 and 3492?±?802 for Types 1-3 samples, respectively) and Y/Ho ratio (20.9?±?0.11, 19.5?±?0.17 and 17.4?±?0.37, respectively) indicate that the three types of apatites may have crystallized from different metasomatic fluids. Multi-stage metasomatism resulted in remobilization and redeposition of primary REE minerals to form the Bayan Obo REE deposit.
DS201805-0979
2018
Tang, H.Song, W., Xi, C., Smith, M.P., Chakhmouradian, A.R., Brenna, M., Kynicky, J., Chen, W., Yang, Y., Tang, H.Genesis of the world's largest rare earth element deposit, Bayan Obo, China: protracted mineralization evolution over ~ 1.b.y.Geology, Vol. 48, 4, pp. 323-326.Chinadeposit - Bayan Obo

Abstract: The unique, giant, rare earth element (REE) deposit at Bayan Obo, northern China, is the world’s largest REE deposit. It is geologically complex, and its genesis is still debated. Here, we report in situ Th-Pb dating and Nd isotope ratios for monazite and Sr isotope ratios for dolomite and apatite from fresh drill cores. The measured monazite ages (361-913 Ma) and previously reported whole-rock Sm-Nd data show a linear relationship with the initial Nd isotope ratio, suggesting a single-stage evolution from a Sm-Nd source that was formed before 913 Ma. All monazites show consistent eNd(1.3Ga) values (0.3 ± 0.6) close to those of the adjacent 1.3 Ga carbonatite and mafic dikes. The primary dolomite and apatite show lower 87Sr/86Sr ratios (0.7024-0.7030) than the recrystallized dolomite (0.7038-0.7097). The REE ores at Bayan Obo are interpreted to have originally formed as products of ca. 1.3 Ga carbonatitic magmatism and to have undergone subsequent thermal perturbations induced by Sr-rich, but REE-poor, metamorphic fluids derived from nearby sedimentary rocks.
DS200812-1322
2008
Tang, H.Y.Zheng, J.P., Sun, M., Griffin, W.L., Zhou, M.F., Zhao, G.C., Robinson, P., Tang, H.Y., Zhang, Z.H.Age and geochemistry of contrasting peridotite types in the Dabie UHP belt, eastern China: petrogenetic and geodynamic implications.Chemical Geology, Vol. 247, pp. 282-304.ChinaUHP
DS200912-0744
2009
Tang, H.Y.Tang, H.Y., Zheng, J.P., Yu, C.M.Age and composition of the Rushan intrusive complex in the northern Sulu orogen, eastern China: petrogenesis and lithospheric mantle evolution.Geological Magazine, Vol. 146, 2, pp. 199-215.ChinaUHP
DS201012-0894
2010
Tang, H.Y.Zhong, J.P., Griffin, W.L., Sun, M., O'Reilly, S.Y., Zhang, H.F., Zhou, J., Xiao, L., Tang, H.Y., Zhang, Z.Tectonic affinity of the west Qingling terrane ( central Chin a): North Chin a or Yangtze?Tectonics, Vol. 29, 2, TC2009ChinaTectonics
DS201212-0826
2012
Tang, H.Y.Zheng, J.P., Griffin, W.L., Ma, Q., O'Reilly, S.Y., Xiong, Q., Tang, H.Y., Zhao, J.H., Yu, C.M., Su, Y.P.Accretion and reworking beneath the North Chin a craton.Lithos, Vol. 149, pp. 61-78.ChinaAccretion
DS201412-0889
2014
Tang, H-J.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
DS201312-0900
2013
Tang, J-L.Tang, J-L., Zhang, H-F., Ying, J-F., Su, B-X.Wide spread fertilization of cratonic and circum-cratonic lithospheric mantle.Earth Science Reviews, Vol. pp. 45-68.MantleSubduction
DS201906-1347
2019
Tang, L.Sing, T.D., Manikyamba, C., Tang, L., Khelen, A.Phanerozoic magmatism in the Proterozoic Cuddapah basin and its connection with the Pangean supercontinent.Geoscience Frontier, doi.org/10.1016/ j.gsf.2019.04.001Indiamagmatism

Abstract: Magmatic pulses in intraplate sedimentary Basins are windows to understand the tectonomagmatic evolution and paleaoposition of the Basin. The present study reports the U-Pb zircon ages of mafic flows from the Cuddapah Basin and link these magmatic events with the Pangean evolution during late Carboniferous-Triassic/Phanerozoic timeframe. Zircon U-Pb geochronology for the basaltic lava flows from Vempalle Formation, Cuddapah Basin suggests two distinct Phanerozoic magmatic events coinciding with the amalgamation and dispersal stages of Pangea at 300 Ma (Late Carboniferous) and 227 Ma (Triassic). Further, these flows are characterized by analogous geochemical and geochronological signatures with Phanerozoic counterparts from Siberian, Panjal Traps, Emeishan and Tarim LIPs possibly suggesting their coeval and cogenetic nature. During the Phanerozoic Eon, the Indian subcontinent including the Cuddapah Basin was juxtaposed with the Pangean LIPs which led to the emplacement of these pulses of magmatism in the Basin coinciding with the assemblage of Pangea and its subsequent breakup between 400 Ma and 200 Ma.
DS201602-0243
2016
Tang, M.Tang, M., Chen, K., Rudnick, R.L.Archean upper crust transition from mafic to felsic marks the onset of plate tectonics.Science, Vol. 351, 6271 pp. 372-375.MantleTectonics

Abstract: The Archean Eon witnessed the production of early continental crust, the emergence of life, and fundamental changes to the atmosphere. The nature of the first continental crust, which was the interface between the surface and deep Earth, has been obscured by the weathering, erosion, and tectonism that followed its formation. We used Ni/Co and Cr/Zn ratios in Archean terrigenous sedimentary rocks and Archean igneous/metaigneous rocks to track the bulk MgO composition of the Archean upper continental crust. This crust evolved from a highly mafic bulk composition before 3.0 billion years ago to a felsic bulk composition by 2.5 billion years ago. This compositional change was attended by a fivefold increase in the mass of the upper continental crust due to addition of granitic rocks, suggesting the onset of global plate tectonics at ~3.0 billion years ago.
DS201806-1257
2018
Tang, M.Tang, M., Erdman, M., Eldridge, G., Lee, C-T.A.The redox filter beneath magmatic orogens and the formation of the continental crust.Science Advances, Vol. 4, 5, 10.1126/ sciadv.eaar 4444Mantlemagmatism

Abstract: The two most important magmatic differentiation series on Earth are the Fe-enriching tholeiitic series, which dominates the oceanic crust and island arcs, and the Fe-depleting calc-alkaline series, which dominates the continental crust and continental arcs. It is well known that calc-alkaline magmas are more oxidized when they erupt and are preferentially found in regions of thick crust, but why these quantities should be related remains unexplained. We use the redox-sensitive behavior of europium (Eu) in deep-seated, plagioclase-free arc cumulates to directly constrain the redox evolution of arc magmas at depth. Primitive arc cumulates have negative Eu anomalies, which, in the absence of plagioclase, can only be explained by Eu being partly reduced. We show that primitive arc magmas begin with low oxygen fugacities, similar to that of mid-ocean ridge basalts, but increase in oxygen fugacity by over two orders of magnitude during magmatic differentiation. This intracrustal oxidation is attended by Fe depletion coupled with fractionation of Fe-rich garnet. We conclude that garnet fractionation, owing to its preference for ferrous over ferric iron, results in simultaneous oxidation and Fe depletion of the magma. Favored at high pressure and water content, garnet fractionation explains the correlation between crustal thickness, oxygen fugacity, and the calc-alkaline character of arc magmas.
DS201905-1080
2019
Tang, M.Tang, M., Lee, C-T.A., Rudnick, R.L., Condie, K.C.Rapid mantle convection drove massive crustal thickening in the late Archean. ( excluded kimberlites)Geochimica et Cosmochimica Acta, in press available, 32p.Asia, Tibet, Andesmelting

Abstract: The lithospheric mantle beneath Archean cratons is conspicuously refractory and thick compared to younger continental lithosphere (Jordan, 1988, Boyd, 1989; Lee and Chin, 2014), but how such thick lithospheres formed is unclear. Using a large global geochemical database of Archean igneous crustal rocks overlying these thick cratonic roots, we show from Gd/Yb- and MnO/FeOT-SiO2 trends that crustal differentiation required continuous garnet fractionation. Today, these signatures are only found where crust is anomalously thick (60-70?km), as in the Northern and Central Andes and Southern Tibet. The widespread garnet signature in Archean igneous suites suggests that thickening occurred not only in the lithospheric mantle but also in the crust during continent formation in the late Archean. Building thick crust requires tectonic thickening or magmatic inflation rates that can compete against gravitational collapse through lower crustal flow, which would have been enhanced in the Archean when geotherms were hotter and crustal rocks weaker. We propose that Archean crust and mantle lithosphere formed by thickening over mantle downwelling sites with minimum strain rates on the order of 10-13-10-12 s-1, requiring mantle flow rates associated with late Archean crust formation to be 10-100 times faster than today.
DS202006-0951
2020
Tang, M.Tang, M., Lee, C-T.A., Rudnick, R.L., Condie, K.C.Rapid mantle convection drove massive crustal thickening in the late Archean.Geochimica et Cosmochimica Acta, Vol. 278, pp. 6-15.Mantlecraton

Abstract: The lithospheric mantle beneath Archean cratons is conspicuously refractory and thick compared to younger continental lithosphere ( Jordan, 1988 , Boyd, 1989 ; Lee and Chin, 2014), but how such thick lithospheres formed is unclear. Using a large global geochemical database of Archean igneous crustal rocks overlying these thick cratonic roots, we show from Gd/Yb- and MnO/FeOT-SiO2 trends that crustal differentiation required continuous garnet fractionation. Today, these signatures are only found where crust is anomalously thick (60-70?km), as in the Northern and Central Andes and Southern Tibet. The widespread garnet signature in Archean igneous suites suggests that thickening occurred not only in the lithospheric mantle but also in the crust during continent formation in the late Archean. Building thick crust requires tectonic thickening or magmatic inflation rates that can compete against gravitational collapse through lower crustal flow, which would have been enhanced in the Archean when geotherms were hotter and crustal rocks weaker. We propose that Archean crust and mantle lithosphere formed by thickening over mantle downwelling sites with minimum strain rates on the order of 10-13-10-12 s-1, requiring mantle flow rates associated with late Archean crust formation to be 10-100 times faster than today.
DS200712-1235
2007
Tang, Q.Zhao, L., Zheng, T., Chen, L., Tang, Q.Shear wave splitting in eastern and central China: implications for upper mantle deformation beneath continental margin.Physics of the Earth and Planetary Interiors, Vol. 162, 1-2, pp. 73-84.ChinaGeophysics - seismics
DS200712-1236
2007
Tang, Q.Zhao, L., Zheng, T., Chen, L., Tang, Q.Shear wave splitting in eastern and central China: implications for upper mantle deformation beneath continental margin.Physics of the Earth and Planetary Interiors, Vol. 162, 1-2, pp. 73-84.ChinaGeophysics - seismics
DS1988-0101
1988
Tang, R.B.Cai Xiucheng, Guo, J.G., Chen, F., Tang, R.B.EPR study of atom pairs of impurity nitrogen in natural diamond. *CHIKexue Tong, *CHI, Vol. 33, No. 22, November pp. 1886-1889GlobalNatural diamond, Diamond inclusions-nitrog
DS201012-0892
2010
Tang, S.Zhao, X., Zhang, H., Zhu, X., Tang, S., Tang, Y.Iron isotope variations in spinel peridotite xenoliths from North Chin a craton: implications for mantle metasomatism.Contributions to Mineralogy and Petrology, Vol. 160, 1, pp. 1-14.ChinaXenoliths
DS201608-1441
2016
Tang, S.Song, Z., Lu, T., Tang, S., Ke, J., Su, J., Gao, B., Bi, L., Wang, D.Identification of colourless HPHT grown synthetic diamonds from Shandong China.The Journal of Gemmology, Vol. 35, 2, pp. 14-147.ChinaSynthetics
DS201804-0747
2017
Tang, S.Tang, S., Song, Z., Lu, T., Su, J., Ma, Y.Two natural type IIa diamonds with strong phosphorescence and Ni related defects.Gems & Gemology Lab Notes, Vol. 53, 4, pp. 476-478.Technologyfluoresecence

Abstract: Strong phosphorescence under UV excitation is rarely seen in natural diamond and normally limited to hydrogen-rich type Ia or type IaA/Ib chameleons and type IIb diamonds (T. Hainschwang et al., "A gemological study of a collection of chameleon diamonds," Spring 2005 G&G, pp. 20-35; S. Eaton-Magaña and R. Lu, "Phosphorescence in type IIb diamonds," Diamond and Related Materials, Vol. 20, No. 7, 2011, pp. 983-989). When seen in other diamond types, an even rarer occurrence, it is shorter and less intense. Recently, the National Gemstone Testing Center (NGTC) in Beijing encountered two natural diamonds that showed extraordinarily strong blue phosphorescence and uncommon fluorescence colors under the DiamondView.
DS201808-1792
2018
Tang, S.Tang, S., Su, J., Lu, T., Ma, Y., Ke, J., Song, Z., Zhang, S., Liu, H.A thick overgrowth of CVD synthetic diamond on a natural diamond.Journal of Gemmology, Vol. 36, 2, pp. 134-141.Technologysynthetics

Abstract: In October 2017, a natural diamond overgrown by a thick layer of CVD synthetic diamond was identified at the Beijing laboratory of the National Gemstone Testing Center (NGTC). The round-brilliant-cut sample was near-colourless and weighed 0.11 ct. No sign of the overgrowth was observed with magnification. However, DiamondView images showed a distinct boundary in the pavilion separating layers of different luminescence: The upper layer displayed red fluorescence with greenish blue phosphorescence, while the lower portion showed deep blue fluorescence and no phosphorescence. Infrared spectroscopy revealed that the upper layer was type IIa and the lower portion was type Ia. Ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy recorded an unusual co-existence of the N3 centre at 415 nm together with absorption due to [Si-V]-defects at 737 nm. The photoluminescence (PL) spectrum confirmed a high level of [Si-V]-defects. The approximate thickness of the CVD synthetic layer was ~740 µm, which is much thicker than previously reported for such overgrowths. The presence of the N3 centre in the natural diamond layer caused this sample to be passed as natural by various screening instruments. Luminescence imaging is key to identifying such overgrowths, and should be relied upon more heavily in the screening procedures used by gemmological laboratories in the future.
DS201901-0043
2018
Tang, S.Ke, J., Lu, T., Lan, Y., Song, Z., Tang, S., Zhang, J., Chen, H.Recent developments in detection and gemology in China, particularly for Chinese synthetic diamonds.Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 268.Chinasynthetics

Abstract: China is the world’s largest producer of HPHT-grown industrial diamonds. Its 2016 production of about 20 billion carats accounted for 98% of the global supply. Since the beginning of 2015, meleesized colorless HPHT synthetic diamonds have been tested at the National Gemstone Testing Center’s (NGTC) Shenzhen and Beijing laboratories in parcels submitted by different clients, which means that colorless HPHT synthetic diamonds have entered the Chinese jewelry market and may be mistaken for natural diamonds. CVD synthesis technology has grown rapidly in recent years. Large colorless and colored (blue, pink) CVD-grown diamonds have been entering the market, and a few have been fraudulently sold as natural diamonds. China has independently developed gem-grade HPHT synthetic diamond production technology since 2002, and can grow gem-grade type Ib, IIa, and IIb and high-nitrogen-content synthetic diamonds in volume, depending on market needs. Gemgrade type Ib, IIa, and IIb HPHT synthetic diamonds have been grown using the temperature gradient method, under a cubic press at high pressure (e.g., 5.4 GPa) and high temperature (1300-1600°C). Driven by a specific temperature gradient, the carbon source from high-purity graphite (>99.9%) located at the high-temperature zone can diffuse into the seed crystals in the cubic press, resulting in the crystallization of synthetic diamonds. Chinese production of melee-sized colorless to near-colorless HPHT synthetic diamonds accounts for about 90% of the global output. Gem-grade type IIa and IIb CVD synthetic diamonds are grown using the microwave plasma chemical vapor deposition (MPCVD) and direct current (DC) arc plasma methods. Faceted colorless CVD diamonds can be grown in sizes up to 6 ct by at least two Chinese companies (table 1). After testing and analyzing thousands of natural and synthetic diamonds collected directly from the Chinese companies, NGTC independently developed the GV5000, PL5000, DS5000, and ADD6000 instruments for rapidly screening and identifying the diamonds based on the gemological characteristics obtained. Besides HPHT and CVD synthetic diamonds, a thickly layered hybrid diamond consisting of both natural and CVD material was identified at the NGTC Beijing laboratory (figure 1). The identification features and properties of regrown CVD synthetic diamonds using natural type Ia diamond crystals as seeds will be reported. The current status and features of colored stones examined at NGTC laboratories, including several cases studies, will be discussed.
DS202003-0365
2019
Tang, S.Tang, S., Liu, H., Yan, S., Xu, X., Wu, W., Fan, J., Liu, J., Hu, C., Tu, L.A high sensitivity MEMS gravimeter with a large dynamic range. ( not specific to diamonds)Nature.com Microsystems & Nanoengineering, Vol. 5, doi:org/10.1038/ s41378-019-0089-7Globalgeophysics - gravity

Abstract: Precise measurement of variations in the local gravitational acceleration is valuable for natural hazard forecasting, prospecting, and geophysical studies. Common issues of the present gravimetry technologies include their high cost, high mass, and large volume, which can potentially be solved by micro-electromechanical-system (MEMS) technology. However, the reported MEMS gravimeter does not have a high sensitivity and a large dynamic range comparable with those of the present commercial gravimeters, lowering its practicability and ruling out worldwide deployment. In this paper, we introduce a more practical MEMS gravimeter that has a higher sensitivity of 8?µGal/vHz and a larger dynamic range of 8000 mGal by using an advanced suspension design and a customized optical displacement transducer. The proposed MEMS gravimeter has performed the co-site earth tides measurement with a commercial superconducting gravimeter GWR iGrav with the results showing a correlation coefficient of 0.91.
DS2000-0947
2000
Tang, W.Tang, W., Bao, C.Characteristics of the geotectonics in South Chin a and their constraints on primary diamond.Acta Geol. Sinica, Vol. 74, No. 2, pp. 217-22.ChinaTectonics - geodynamics
DS201911-2578
2019
Tang, W.Xu, Y., Tang, W., Hui, H., Rudnick, R.L., Shang, S., Zhang, Z.Reconciling the discrepancy between the dehydration rates in mantle olivine and pyroxene during xenolith emplacement. Lashaine, Eledoi, KisiteGeochimica et Cosmochimica Acta, Vol. 267, pp. 179-195.Africa, Tanzaniaperidotite

Abstract: Hydrogen concentration profiles through olivine and pyroxene in peridotite xenoliths carried in rift basalts from northern Tanzania (Lashaine, Eledoi, and Kisite localities) show bell-shaped distributions, indicating that diffusive hydrogen loss has occurred in all minerals. Homogeneous major element concentrations and equilibration of hydrogen between the cores of olivine and coexisting pyroxene suggest that hydrogen loss resulted from diffusive degassing during host magma emplacement. For these samples, hydrogen diffusivities in olivine and coexisting pyroxene must be within the same order of magnitude, similar to experimentally determined diffusivities, but in contrast to previous observations made on xenolithic peridotites. We demonstrate here, for the first time using natural samples, that significant differences in activation energy is likely the primary parameter that causes the discrepancy between hydrogen diffusion in olivine and pyroxene observed in different suites of mantle xenoliths. Because hydrogen diffuses faster in olivine than in pyroxene as temperature increases, hydrogen loss in the Tanzanian mantle xenoliths must have occurred at relatively low temperatures (~750 - ~900 °C), whereas hydrogen loss observed in previous xenolith studies likely occurred at higher temperatures (~950 to > 1200 °C). Thus, the diffusive loss of hydrogen in the Tanzanian mantle xenoliths may have occurred at shallow depths or at the Earth’s surface.
DS202003-0348
2020
Tang, W.C.Lee, C.W.Y., Cheng, J., Yium Y.C., Chan, K., Lau, D., Tang, W.C., Cheng, K.W,m Kong, T., Hui, T.K.C., Jelezko, F.Correlation between EPR spectra and coloration of natural diamonds.Diamond & Related Materials, Vol. 103, 13p. PdfGlobaldiamond colour

Abstract: White diamonds color grading is one of the basic diamond evaluations. The color value based on a scale that ranges from D to Z, with D being the more colorless and more valuable, among other qualifications. As the diamond grade moves on this scale, its color appears more yellow progressively. This yellowish color, present only in Type I diamonds, is mainly due to the nitrogen related defects such as N3 center and C-center. The current color grading system is based on a visual method, where gemologist compares the sample with a Master Color set. However, this method is very subjective. Several defects responsible for light absorption in diamond are carrying electron spin and appear in Electron Paramagnetic Resonance (EPR) spectrum. In this study, we developed a new EPR based technique for a quantitative measurement of N3 center and C-center in diamond through quantitative EPR spectroscopy. The correlation between EPR spectra and color grades of diamond was established.
DS201412-0911
2014
Tang, X.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, Vol. 41, 8, pp. 2746-2752.MantleGeothermometry
DS201412-0912
2014
Tang, X.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S.G., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, Apr. 16 DOI: 10.1002/2014 GL059385MantleGeothermometry
DS201412-0913
2014
Tang, X.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S.G., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, April 16, pp. 2746-2742.MantleGeothermometry
DS201412-0914
2014
Tang, X.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S.G., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, Vol. 41, 8, pp. 2746-2752.MantleGeothermometry
DS201012-0764
2010
Tang, Y.Su, B., Zhang, H., Tang, Y., Chisonga, B., Qin, K., Ying, J., Sakyi, P.A.Geochemical syntheses among the cratonic, off-cratonic and orogenic garnet peridotites and their tectonic implications.International Journal of Earth Sciences, In press available, 21p.MantlePeridotite, geochemistry
DS201012-0892
2010
Tang, Y.Zhao, X., Zhang, H., Zhu, X., Tang, S., Tang, Y.Iron isotope variations in spinel peridotite xenoliths from North Chin a craton: implications for mantle metasomatism.Contributions to Mineralogy and Petrology, Vol. 160, 1, pp. 1-14.ChinaXenoliths
DS201112-1015
2011
Tang, Y.Su, B., Zhang, H., Tang, Y., Chisonga, B., On, K., Ying, J., Sakyi, P.A.Geochemical syntheses among the cratonic, off cratonic and orogenic garnet peridotites and their tectonic implications.International Journal of Earth Sciences, Vol. 100, 4, pp.695-715.MantleCraton, kimberlites mentioned
DS200812-1150
2008
Tang, Y.J.Tang, Y.J., Zhang, H.F., Yong, J.F., Zhang, J., Liu, X.M.Refertilization of ancient lithosphere mantle beneath the central North Chin a craton: evidence from petrology and geochemistry of peridotite xenoliths.Lithos, Vol. 101, 3-4, pp. 435-452.ChinaGeochemistry
DS200712-1067
2007
Tang, Y-J.Tang, Y-J., Zhang, H-F., Nakamura, E., Moriguti, T., Kobayashi, K., Ying, J-F.Lithium isotopic systematics of peridotite xenoliths from Hannuoba, North Chin a Craton: implications for melt rock interaction in considerably thinned mantle lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 71, 17, Sept. 1, pp. 4327-4341.ChinaGeochronology
DS200712-1225
2007
Tang, Y-J.Zhang, H-F., Nakamura, E., Sun, M., Kobayashi,K., Zhang, J., Yang, J-F., Tang, Y-J.Transformation of subcontinental lithospheric mantle through peridotite melt reaction: evidence from a highly fertile mantle xenolith from the North Chin a Craton.International Geology Review, Vol. 49, 7, July pp. 658-679.ChinaMelting
DS201012-0765
2010
Tang, Y-J.Su, B-X., Zhang, H-F., Sakyi, P.A., Yang, Y-H., Ying, J-F., Tang, Y-J., Qin, K-Z., Xiao, Y., Zhao, Mao, MaThe origin of spongy texture in minerals of mantle xenoliths from the western Qinling, central China.Contributions to Mineralogy and Petrology, in press available, 18p.ChinaXenoliths
DS201012-0766
2010
Tang, Y-J.Su, B-X., Zhang, H-F., Sakyi, P.A., Ying, J-F., Tang, Y-J., Yang, Y-H., Qin, K-Z., Xiao, Y., Zhao, X-M.Compositionally stratified lithosphere and carbonatite metasomatism recorded in mantle xenoliths from the Western Qinling (Central China).Lithos, Vol. 116, pp. 111-128.ChinaCarbonatite
DS201012-0888
2010
Tang, Y-J.Zhang, H-F., Nakamura, E., Kobayashi, K., Ying, J-F., Tang, Y-J.Recycled crustal melt injection into lithospheric mantle: implication from cumulative composite and pyroxenite xenoliths.International Journal of Earth Sciences, Vol. 99, pp. 1167-1186.ChinaNorth China craton
DS201112-1027
2011
Tang, Y-J.Tang, Y-J., Zhang, H-F., Nakamura, E., Ying, J-F.Multistage melt fluid peridotite interactions in the refertilized lithospheric mantle beneath the North Chin a craton: constrains from the Li Sr Nd isotopicContributions to Mineralogy and Petrology, Vol. 161, 6, pp.MantlePeridotitic xenoliths
DS201212-0815
2012
Tang, Y-J.Zhang, P.-F., Tang, Y-J., Hu, Y., Zhang, H-F., Su, B-X., Xiao, Y., Santosh, M.Review of melting experiments on carbonated eclogite and peridotite: insights into mantle metasomatism.International Geology Review, in press availableMantleMetasomatism
DS201212-0816
2012
Tang, Y-J.Zhang, P=F., Tang, Y-J., Hu, Y., Zhang, H-F., Su, B-X., Xiao, Y., Santosh, M.Review of melting experiments on carbonated eclogite and peridotite: insights into mantle metasomatism.International Geology Review, In press availableMantleMetasmatism
DS201212-0716
2013
Tang, Y-L.Tang, Y-L., Zhang, H-F., Ying, J-F., Su, B-X., Chu, Z.Y., Xiao, Y., Zhao, X-M.Highly heterogeneous lithospheric mantle beneath the Central Zone of the North Chin a Craton evolved from Archean mantle through diverse melt refertilization.Gondwana Research, Vol. 23, 1, pp. 130-140.ChinaMelting
DS202010-1857
2020
Tang, Y-W. SheLiu, S., Ding, L., Fan, H-R., Yang, K-F., Tang, Y-W. She, H-D, Hao, M-z.Hydrothermal genesis of Nb mineralization in the giant Bayan Obo REE-Nb-Fe deposit ( China): implicated by petrography and geochemistry of Nb-bearing minerals.Precambrian Research, Vol. 348, 105864 24p. PdfChinadeposit - Bayan Obo

Abstract: The Bayan Obo REE-Nb-Fe deposit, which reserves the current largest REE resources globally, also hosts over 70% of China’s Nb resources. Unlike many world-class carbonatite-related Nb deposits (e.g. Morro dos Seis Lagos and Araxá, Brazil) with igneous or secondary origin, Nb was mainly stored in Nb-bearing minerals (aeschynite, ilmenorutile, baotite, fergusonite etc.) of hydrothermal origin at Bayan Obo, supported by evidence from petrography, element and isotopic geochemistry. Although igneous fersmite and columbite were occasionally discovered in local carbonatite dykes, the Mesoproterozoic and Paleozoic hydrothermal metasomatism occurred in the ore-hosting dolomite, related to carbonatite intrusion and the closure of Paleo-Asian Ocean respectively, has played a more significant role during the ultimate Nb enrichment. REE, however, was significantly enriched during both the carbonatite-related magmatic and hydrothermal processes. Consequently, there was differentiated mineralization between REE and Nb in the carbonatite dykes and the ores. Niobium mineralization at Bayan Obo is rather limited in Mesoproterozoic carbonatite, whereas more extensive in the metasomatized ore-hosting dolomite, and generally postdating the REE mineralization at the same stage. According to mineral geochemistry, Bayan Obo aeschynite was classified into 3 groups: aeschynite-(Nd) with convex REE patterns (Group 1); aeschynite-(Ce) (Group 2) and nioboaeschynite (Group 3) with nearly flat REE patterns. Aeschynite (Group 1), ilmenorutile and fergusonite precipitated from Paleozoic hydrothermal fluids with advanced fractionation of Ce-rich REE minerals. The Mesoproterozoic hydrothermal Nb mineralization, represented by aeschynite (Group 3) and baotite, occurred postdating REE mineralization at same stage. Besides, fersmite and aeschynite (Group 2) precipitated from the Mesoproterozoic REE-unfractionated melt and hydrothermal fluids, respectively. All above Nb-bearing minerals exhibit extreme Nb-Ta fractionation as a primary geochemical characteristic of mantle-derived carbonatite. The forming age of the aeschynite megacrysts (Group 1) has not been accurately determined. However, the potential age was constrained to ~430 Ma or alternatively ~270-280 Ma subjected to subduction and granite activity, respectively. These aeschynite crystals inherited REEs from multiphase former REE mineralization, with an intermediate apparent Sm-Nd isochron age between the Mesoproterozoic and the Paleozoic REE mineralization events.
DS1991-1933
1991
Tang JianminZhou Xiouzhong, Tang Jianmin, Huang Yunhui, et al.rare earth elements (REE) geochemistry characteristics of kimberlites in Shandong and China.*CHIMineralogia, *CHI, Vol. 9, No. 4, pp. 300-308ChinaGeochemistry, Rare earths
DS1992-1701
1992
Tang LianjiangWu Jianshan, Geng Yuansheng, Tang Lianjiang, Zang AndiRelationship of Diamondiferous kimberlites with tectonic setting of basement in Sino-Korean PlatformRussian Geology and Geophysics, Vol. 33, No. 10, 5p.ChinaStructure, Sino-Korean Platform
DS1988-0682
1988
Tang MingTang Ming, Anders, E.Isotopic anomalies of Neodynium, Xenon, and Carbon in meteorites:II. Interstellar diamond and SiC: carriers of exotic noblegases.see also pts. 1, 2. sGeochimica et Cosmochimica Acta, Vol. 52, No. 5, May pp. 1235-1244Globalmeteorites, carbon, xenon
DS1986-0119
1986
Tang RongbingCai Xiucheng, Guo Jiugao, Chen Feng, Fu Yude, Tang Rongbing, TanDistribution of paramagnetic nitrogen in placer diamonds with specialAcad. Sin. Institute Geochem., Guiyang, *CHI, Vol. 6, No. 3, September pp. 195-202ChinaAlluvials, Geochemistry, diamond inclusions
DS1986-0120
1986
Tang RongbingCai Xiucheng, Guo Jiugao, Chen, Feng, Fu, Yude, Tang Rongbing, TanDistribution of paramagnetic nitrogen in placer diamonds with Special reference to its significance in diamond classification. *CHIKuangwu Xuebao, *CHI, Vol. 6, No. 3, pp. 195-202ChinaAlluvials, Diamond inclusions-nitrog
DS201012-0312
2010
TangeIrifune, T., Nishiyama, Tange, Kono, Shinmel, Kinoshita, Negishi, Kato, Higo, FunakoshiPhase transitions, densities and sound velocities of mantle and slab materials down to the upper part of the lower mantle.International Mineralogical Association meeting August Budapest, abstract p. 142.MantleSubduction
DS201911-2534
2019
Tange, H.Ishi, T., Huang, R., Myhill, R., Fei, H., Koemets, I., Liu, Z., Maeda, F., Yuan, L., Wang, L., Druzhbin, D., Yamamoto, T., Bhat, S., Farla, R., Kawazoe, T., Tsujino, N., Kulik, E., Higo, Y., Tange, H., Katsura, T.Sharp 660 km discontinuity controlled by extremely narrow binary post-spinel transition.Nature Geosciences, Vol. 12, pp. 869-872.Mantlediscontinuity

Abstract: The Earth’s mantle is characterized by a sharp seismic discontinuity at a depth of 660?km that can provide insights into deep mantle processes. The discontinuity occurs over only 2?km—or a pressure difference of 0.1?GPa—and is thought to result from the post-spinel transition, that is, the decomposition of the mineral ringwoodite to bridgmanite plus ferropericlase. Existing high-pressure, high-temperature experiments have lacked the pressure control required to test whether such sharpness is the result of isochemical phase relations or chemically distinct upper and lower mantle domains. Here, we obtain the isothermal pressure interval of the Mg-Fe binary post-spinel transition by applying advanced multi-anvil techniques with in situ X-ray diffraction with the help of Mg-Fe partition experiments. It is demonstrated that the interval at mantle compositions and temperatures is only 0.01?GPa, corresponding to 250?m. This interval is indistinguishable from zero at seismic frequencies. These results can explain the discontinuity sharpness and provide new support for whole-mantle convection in a chemically homogeneous mantle. The present work suggests that distribution of adiabatic vertical flows between the upper and lower mantles can be mapped on the basis of discontinuity sharpness.
DS201212-0717
2012
Tange, Y.Tange, Y., Kuwayma, Y., Irifune, T., Funakoshi, K-I., Ohishi, Y.P-V-T equation of state of MgSiO3 perovskite based on the MgO pressure scale: a comprehensive reference for mineralogy of the lower mantle.Journal of Geophysical Research, Vol. 117, B6, B06201MantlePerovskite
DS201312-0652
2013
Tange, Y.Nishi, M., Irifune, T., Ohfuji, H., Tange, Y.Intracrystalline nucleation during the post garnet transformation under large overpressure conditions in deep subducting slabs.Geophysical Research Letters, Vol. 39, 23,MantleSubduction
DS201412-0631
2014
Tange, Y.Nishi, M., Irifune, T., Tsuchiya, J., Tange, Y., Nishihara, Y., et al.Stability of hydrous silicate at high pressures and water transport to the deep lower mantle.Science, Vol. 343, pp. 522-525.MantleSubduction
DS201811-2597
2018
Tange, Y.Ohuchi, T., Lei, X., Higo, Y., Tange, Y., Sakai, T., Fujino, K.Semi-brittle behavior of wet olivine aggregates: the role of aqueous fluid in faulting at upper mantle pressures.Contributions to Mineralogy and Petrology, Vol. 173, 21p. Doi.org/10.1007/s00410-018-1515-9Mantlesubduction

Abstract: The role of aqueous fluid in fracturing in subducting slabs was investigated through a series of deformation experiments on dunite that was undersaturated (i.e., fluid-free) or saturated with water (i.e., aqueous-fluid bearing) at pressures of 1.0-1.8 GPa and temperatures of 670-1250 K, corresponding to the conditions of the shallower regions of the double seismic zone in slabs. In situ X-ray diffraction, radiography, and acoustic emissions (AEs) monitoring demonstrated that semi-brittle flow associated with AEs was dominant and the creep/failure strength of dunite was insensitive to the dissolved water content in olivine. In contrast, aqueous fluid drastically decreased the creep/failure strength of dunite (up to ~ 1 GPa of weakening) over a wide range of temperatures in the semi-brittle regime. Weakening of the dunite by the aqueous fluid resulted in the reduction of the number of AE events (i.e., suppression of microcracking) and shortening of time to failure. The AE hypocenters were located at the margin of the deforming sample while the interior of the faulted sample was aseismic (i.e., aseismic semi-brittle flow) under water-saturated conditions. A faulting (slip rate of ~ 10?³ to 10?4 s?¹) associated with a large drop of stress (?s ~ 0.5 to 1 GPa) and/or pressure (?P ~ 0.5 GPa) was dominant in fluid-free dunite, while a slow faulting (slip rate < 8 × 10?5 s?¹) without any stress/pressure drop was common in water-saturated dunite. Aseismic semi-brittle flow may mimic silent ductile flow under water-saturated conditions in subducting slabs.
DS201810-2326
2018
Tani, K.Guotana, J.M., Morishita, T., Yamaguchi, R., Nishio, I., Tamura, A., Tani, K., Harigane, Y., Szilas, K., Pearson, D.G.Contrasting textural and chemical signatures of chromitites in the Mesoarchean Ulamertoq peridotite body, southern West Greenland.MDPI Geosciences, Researchgate 19p.Europe, Greenlandperidotite

Abstract: Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting metamorphic textural and chemical features. Chromitite layers from different localities in Ulamertoq show contrasting characteristics. In one locality, zoned chromites are hosted in orthopyroxene-amphibole peridotites. Compositional zonation in chromites is evident with decreasing Cr and Fe content from core to rim, while Al and Mg increase. Homogeneous chromites from another locality are fairly uniform and Fe-rich. The mineral chemistry of the major and accessory phases shows metamorphic signatures. Inferred temperature conditions suggest that the zoned chromites, homogeneous chromites, and their hosts are equilibrated at different metamorphic conditions. In this paper, various mechanisms during the cumulus to subsolidus stages are explored in order to understand the origin of the two contrasting types of chromites.
DS201905-1037
2019
Tani, K.Guotana, J.M., Morishita, T., Yamaguschi, R., Nishio, I., Tamura, A., Tani, K., Harigane, Y., Szilas, K., Pearson, D.G.Contrasting textural and chemical signatures of chromitites in the Mesoarchean Ulamertoq peridotite body, southern west Greenland.Geosciences ( MDPI), Vol. 8, 328- 19p.Europe, Greenlandchromitite

Abstract: Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting metamorphic textural and chemical features. Chromitite layers from different localities in Ulamertoq show contrasting characteristics. In one locality, zoned chromites are hosted in orthopyroxene-amphibole peridotites. Compositional zonation in chromites is evident with decreasing Cr and Fe content from core to rim, while Al and Mg increase. Homogeneous chromites from another locality are fairly uniform and Fe-rich. The mineral chemistry of the major and accessory phases shows metamorphic signatures. Inferred temperature conditions suggest that the zoned chromites, homogeneous chromites, and their hosts are equilibrated at different metamorphic conditions. In this paper, various mechanisms during the cumulus to subsolidus stages are explored in order to understand the origin of the two contrasting types of chromites.
DS201905-1064
2019
Tani, K-I.Nishio, I., Morishita, T., Szilas, K., Pearson, G., Tani, K-I., Tamura, A., Harigane, Y., Guotana, J.M.Titanium clinohumite bearing peridotite from the Ulamertoq ultramafic body in the 3.0 Ga Akia terrane of southern west Greenland.Geosciences ( MDPI), 20p. Europe, Greenlandperidotite

Abstract: A titanian clinohumite-bearing dunite was recently found in the Ulamertoq ultramafic body within the 3.0 Ga Akia Terrane of southern West Greenland. Titanian clinohumite occurs as disseminated and discrete grains. Titanian clinohumite contains relatively high amounts of fluorine, reaching up to 2.4 wt.%. The high-Fo content of olivine (Fo93) coupled with low Cr/(Cr + Al) ratio of orthopyroxene implies that the dunite host is not of residual origin after melt extraction by partial melting of the primitive mantle. Olivine grains are classified into two types based on abundances of opaque mineral inclusions: (1) dusty inclusion-rich and (2) clear inclusion-free olivines. Opaque inclusions in coarse-grained olivines are mainly magnetite. Small amounts of ilmenite are also present around titanian clinohumite grains. The observed mineral association indicates partial replacement of titanian clinohumite to ilmenite (+magnetite) and olivine following the reaction: titanian clinohumite = ilmenite + olivine + hydrous fluid. The coexistence of F-bearing titanian clinohumite, olivine, and chromian chlorite indicates equilibration at around 800-900 °C under garnet-free conditions (<2 GPa). Petrological and mineralogical characteristics of the studied titanian clinohumite-bearing dunite are comparable to deserpentinized peridotites derived from former serpentinites. This study demonstrates the importance of considering the effects of hydration/dehydration processes for the origin of ultramafic bodies found in polymetamorphic Archaean terranes.
DS2003-0825
2003
Taniguchi, H.Litasov, K.D., Litasov, Y.D., Malkovets, V.G., Taniguchi, H.Lithosphere structure and thermal regime of the upper mantle beneath the Baikal region:8 Ikc Www.venuewest.com/8ikc/program.htm, Session 9, POSTER abstractRussiaBlank
DS200412-1145
2003
Taniguchi, H.Litasov, K.D., Litasov, Y.D., Malkovets, V.G., Taniguchi, H.Lithosphere structure and thermal regime of the upper mantle beneath the Baikal region: evidence from deep seated xenoliths.8 IKC Program, Session 9, POSTER abstractRussiaCraton studies
DS200512-1068
2005
Taniguchi, M.Taniguchi, M., Kukkonen, I.T.Thermally controlled processes and preserved thermal signatures within the Earth.Physics of the Earth and Planetary Interiors, In pressMantleGeothermometry
DS1995-0893
1995
Taniguchi, T.Jones, A.P., Taniguchi, T., Dobson, D., Milledge, H.J.Experimental nucleation and growth of diamond from carbonate graphitesystems.Geological Society Africa 10th. Conference Oct. Nairobi, p. 119. Abstract.GlobalPetrology -experimental, Diamond
DS1995-0894
1995
Taniguchi, T.Jones, A.P., Taniguchi, T., Dobson, D., Rabe, R., MilledgeExperimental nucleation and growth of diamond from carbonate-graphitesystems.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 269-270.GlobalPetrology -experimental, Diamond nucleation
DS200912-0284
2009
Taniguchi, T.Harte, B., Taniguchi, T., Chakraborty, S.Diffusion in diamond. II. High pressure temperature experiments.Mineralogical Magazine, Vol.73, 2, April, pp. 201-204.TechnologyUHP
DS1991-1181
1991
Tanimoto, T.Montagner, J-P., Tanimoto, T.Global upper mantle tomography of seismic velocities and anisotropiesJournal of Geophysical Research, Vol. 96, No. B12, November 10, pp. 20, 337-20, 351MantleMantle tomography, Geophysics -seismics
DS1992-0025
1992
Tanimoto, T.Anderson, D.L., Tanimoto, T., Zhang, Yu-ShenPlate tectonics and hotspots: the third dimensionScience, Vol. 256, June 19, pp. 1645-1651MantleHot spots, Shear velocity
DS1992-0026
1992
Tanimoto, T.Anderson, D.L., Yu-Sheng Zhang, Tanimoto, T.Plume heads, continental lithosphere, flood basalts and tomographyGeological Society Special Publication Magmatism and the causes of the, No. 68, pp. 99-124GlobalMantle, Hotspots
DS1992-0027
1992
Tanimoto, T.Anderson, D.L., Zhang, Y., Tanimoto, T.Plume heads, continental lithosphere, flood basalts and tomographyStorey ed. Geological Society of London Special Paper, No. 68, pp. 99-124.MantleHot spots, plumes, volcanism.
DS1992-1089
1992
Tanimoto, T.Morin, P.J., Yuen, D.A., Tanimoto, T., Yu-Shen ZhangVisualizing interactively the three dimensional structure of the earth'smantleEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 197MantleGeophysics, Structure
DS1992-1729
1992
Tanimoto, T.Yu-Shen Zhang, Tanimoto, T.Ridges, hot spots and their interaction as observed in seismic velocitymapsNature, Vol. 355, January 2, pp. 45-49GlobalHot spots, Geophysics
DS1992-1738
1992
Tanimoto, T.Zhang, Y-S., Tanimoto, T.Ridges, hotspots and their interaction as observed in seismic velocitymapsNature, Vol. 355, No. 6355, January 2, pp. 45-49MantleHotspots, Geophysics-seismics
DS1993-1805
1993
Tanimoto, T.Yu-Shen Zhang, Tanimoto, T.High resolution global upper mantle structure and plate tectonicsJournal of Geophysical Research, Vol. 98, No. B6, June 10, pp. 9793-9823.MantleTomography, Geophysics -seismics
DS201810-2394
2018
Tank, S.E.Zolkos, S., Tank, S.E., Kokelj, S.V.Mineral weathering and the permafrost carbon-climate feedback. Peel PlateauGeophysical Research Letters, orchid.org/ 0000-0001-9945-6945Canada, Northwest Territoriespermafrost

Abstract: The origin of the complex pattern of SKS splitting over the western United States (U.S.) remains a long-lasting debate, where a model that simultaneously matches the various SKS features is still lacking. Here we present a series of quantitative geodynamic models with data assimilation that systematically evaluate the influence of different lithospheric and mantle structures on mantle flow and seismic anisotropy. These tests reveal a configuration of mantle deformation more complex than ever envisioned before. In particular, we find that both lithospheric thickness variations and toroidal flows around the Juan de Fuca slab modulate flow locally, but their co-existence enhances large-scale mantle deformation below the western U.S. The ancient Farallon slab below the east coast pulls the western U.S. upper mantle eastward, spanning the regionally extensive circular pattern of SKS splitting. The prominent E-W oriented anisotropy pattern within the Pacific Northwest reflects the existence of sustaining eastward intrusion of the hot Pacific oceanic mantle to beneath the continental interior, from within slab tears below Oregon to under the Snake River Plain and the Yellowstone caldera. This work provides an independent support to the formation of intra-plate volcanism due to intruding shallow hot mantle instead of a rising mantle plume.
DS201412-0460
2014
Tankersley, K.B.Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alcantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M.Nanodiamond rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP Journal of Geology, Vol 122, 5, pp. 475-506.Global, GreenlandNanodiamonds
DS201502-0069
2014
Tankersley, K.B.Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M.Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP.Journal of Geology, Vol. 122, Sept. pp. 475-506.South America, BrazilNanodiamonds
DS1997-1261
1997
Tankut, A.Wilson, M., Tankut, A., Gulec, N.Tertiary volcanism of the Galatia province, northwest central AnatoliaTurkeyLithos, Vol. 42, No. 1-2, Dec. 1, pp. 105-122Globalvolcanism.
DS200412-1232
2004
Tannant, D.D.Martin, M.W., Tannant, D.D.A technique for identifying structural domain boundaries at the Ekati diamond mine.Engineering Geology, Vol. 74, 3-4, pp. 247-264. Ingenta 1042990759Canada, Northwest TerritoriesMining - Ekati
DS200612-1409
2006
Tannant, D.D.Tannant, D.D., Anonby, D.Blast modifications to improve bench width reliability at the Ekati Fox pit.CIM Conference and Exhibition, Vancouver - Creating Value with Values, List of talks CIM Magazine, Feb. p. 78.Canada, Northwest TerritoriesMining - Ekati Fox
DS200712-0690
2004
Tannant, D.D.Martin, M.W., Tannant, D.D.A technique for identifying structural domain boundaries at the Ekati diamond mine.Engineering Geology, Vol. 74, 3-4, August pp. 247-264.Canada, Northwest TerritoriesDeposit - Ekati
DS1992-1517
1992
Tanner, A.B.Tanner, A.B.Bibliography of radon in the outdoor environment and selected reference son gas mobility in the groundUnited States Geological Survey (USGS) Open file, No. 92-0351 A, B 298p. $45.00 plus disc $ 10.00GlobalRadon, Environment
DS1996-1399
1996
Tanner, B.Tanner, B., Meissner, R.Caledonian deformation upon southwest Baltica and its tectonicimplications: alternatives and consequences.Tectonics, Vol. 15, No. 4, Aug. pp. 803-12.Baltic States, GermanyLineaments, tectonics
DS201603-0431
2016
Tanner, D.White, L.T., Graham, I., Tanner, D., Hall, R., Armstrong, R.A., Yaxley, G., Barron, L.The provenance of Borneo's enigmatic alluvial diamonds: a case study from Cempaka, SE Kalimantan.Gondwana Research, in press available 22p.Asia, KalimantanAlluvials, diamonds

Abstract: Gem-quality diamonds have been found in several alluvial deposits across central and southern Borneo. Borneo has been a known source of diamonds for centuries, but the location of their primary igneous source remains enigmatic. Many geological models have been proposed to explain their distribution, including: the diamonds were derived from a local diatreme; they were brought to the surface through ophiolite obduction or exhumation of UHP metamorphic rocks; they were transported long distances southward via major Asian river systems; or, they were transported from the Australian continent before Borneo was rifted from its northwestern margin in the Late Jurassic. To assess these models, we conducted a study of the provenance of heavy minerals from Kalimantan's Cempaka alluvial diamond deposit. This involved collecting U Pb isotopic data, fission track and trace element geochemistry of zircon as well as major element geochemical data of spinels and morphological descriptions of zircon and diamond. The results indicate that the Cempaka diamonds were likely derived from at least two sources, one which was relatively local and/or involved little reworking, and the other more distal which records several periods of reworking. The distal diamond source is interpreted to be diamond-bearing pipes that intruded the basement of a block that: (1) rifted from northwest Australia (East Java or SW Borneo) and the diamonds were recycled into its sedimentary cover, or: (2) were emplaced elsewhere (e.g. NW Australia) and transported to a block (e.g. East Java or SW Borneo). Both of these scenarios require the diamonds to be transported with the block when it rifted from NW Australia in the Late Jurassic. The local source could be diamondiferous diatremes associated with eroded Miocene high-K alkaline intrusions north of the Barito Basin, which would indicate that the lithosphere beneath SW Borneo is thick (~ 150 km or greater). The ‘local’ diamonds could also be associated with ophiolitic rocks that are exposed in the nearby Meratus Mountains.
DS1986-0363
1986
Tanner, J.Hinze, W.J., Kane, M.F., O'Hara, N.W., Reford, M.S., Tanner, J., WeberThe utility of regional gravity and magnetic anomaly mapsSociety of Exploration Geophysicists, Special Volume, 400pUnited States, CanadaGeophysics
DS1988-0683
1988
Tanner, J.G.Tanner, J.G.Gravity anomaly map of North AmericaGeophysics: The leading edge, Nov. pp. 15-21.Canada, United StatesGeophysics - gravity, Map - brief outline
DS201709-1968
2017
Tanner, M.Bussweiler, Y., Poitras, S., Borovinskaya, O., Tanner, M., Pearson, G.Rapid multielemental analysis of garnet with LA-ICP-TOF-MS implications for diamond exploration studies.Goldschmidt Conference, abstract 1p.Canada, Northwest Territoriesdiamond potential

Abstract: Garnet arguably constitutes the most important mineral in diamond exploration studies; not only can the presence of mantle garnet in exploration samples point to kimberlite occurrences, but its minor and trace element composition can further be used to assess the “diamond potential” of a kimberlite. The content of Cr and Ca, especially, has been found to be a reliable tool to test whether garnets originate from within the diamond stability field in the mantle [1]. Trace element patterns can further indicate the mantle host rock of the garnets, for example, whether they originate from a depleted or ultra-depleted mantle section [2]. Routinely, two separate analytical methods are necessary to fully characterize the composition of garnet; major and minor elements are usually determined by electron probe micro-analysis (EPMA), whereas determination of trace elements requires the more sensitive method of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Here, we demonstrate rapid measurement of the entire suite of elements in garnet employing a new, commercially available timeof-flight (TOF) mass spectrometer, the icpTOF (TOFWERK AG, Thun, Switzerland), coupled to a fast wash-out laser ablation system (Teledyne Cetac Technologies Inc., Omaha, NE, USA). Using garnets from exploration samples taken from the Horn Plateau, Northwest Territories, Canada [3], we directly compare the icpTOF results to EPMA and LA-ICP-MS data. We examine whether the icpTOF can reliably characterize the garnets in Cr versus Ca space and at the same time reproduce their trace element patterns, thereby offering a cost effective method of analysis. The method of LA-ICP-TOF-MS, with its high speed of data acquisition and its ability to record the entire mass spectrum simultaneously, may have great benefits for (diamond) exploration studies. Moreover, the method can be used for fast, highresolution imaging, which is applicable to a wide range of geological materials and settings [4].
DS1989-1478
1989
Tanner, P.W.G.Tanner, P.W.G.The flexural-slip mechanisMJournal of Structural Geology, Vol. 11, No. 6, pp. 635-656GlobalStructure, Slip
DS1991-1691
1991
Tanner, P.W.G.Tanner, P.W.G.Metamorphic fluid flowNature, Vol. 352, No. 6335, August 8, pp. 483-484GlobalFluid flow, metamorphism
DS1994-0344
1994
Tanner de Oliveira, M.A.F.Correa Gomes, L.C., Tanner de Oliveira, M.A.F., Cruz, M.Mafic dykes of Bahia: major provinces, temporal evolution and presentknowledge, some evidence.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 59-61.BrazilMafic dykes, Mantle, upper mantle behaviour
DS1995-0137
1995
Tanner de Oliviera, M.A.Bellieni, G., Piccirillo, E.M., Tanner de Oliviera, M.A.Petrological and Sr-neodymium evidence bearing on Early Proterozoic magmatic events of the sub-cont. mantle..Contributions to Mineralogy and Petrology, Vol. 122, No. 3, pp. 252-261BrazilGeochronology, Craton -Sao Francisco
DS1900-0709
1908
Tannhauser, F.Tannhauser, F.Der Diamant und Seine FundstaettenKol. Heimat., Vol. 2, No. 25, PP. 2-5.Africa, NamibiaDiamond Occurrences
DS2000-0366
2000
Tanqueray Resources, Fibre-Klad Industries Ltd.Tanqueray Resources, Fibre-Klad Industries Ltd., Mill City Gold MiningGuyanor says French Guyana diamonds disappointing...Rio pulls out. Poor quality diamonds.Guaynor Resources, Oct. 13, 1p.French GuianaNews item - press release, Rio Tinto
DS1990-1203
1990
Tanre, D.Proy, C., Tanre, D., Deschamps, P.Y.Evaluation of topographic effects in remotely sensed dataRemote Sensing of the Environment, Vol. 30, pp. 21-32Europe, PyreneesRemote sensing, Topography
DS2001-1149
2001
Tanton, L.T.E.Tanton, L.T.E., Grove, T.L., Donnelly-Nolan, J.Hot shallow mantle melting under the Cascades volcanic arcGeology, Vol. 19, No. 7, July pp. 631-4.California, OregonSubduction - not related to diamonds
DS200612-1410
2005
Tanuuja, M.Tanuuja, M.Petrogenesis of Kodomali kimberlite, Mainpur kimberlite field, Raipur District, Chhattisgarh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 102.India, Bastar CratonKimberlite - Kodomali
DS1994-1742
1994
Tanzania EmbassyTanzania EmbassyMining industry perspectives from Embassy, economics and a list of available helpful publications.Tanzania Embassy, Preprint 11p.TanzaniaCountry profile, Economics
DS1992-0924
1992
TaoLeBas, M.J., Keller, J., Kejie, Tao, Wall, F., Williams, C.T., Zhang PeishanCarbonatite dykes at Bayan Obo, Inner Mongolia, ChinaMineralogy and Petrology, Vol. 46, No. 3, pp. 195-228ChinaCarbonatite, Deposit -Bayan Obo
DS2003-0249
2003
Tao, G.Cheng, X., Zhilong, H.,Congqiang, L., Liang, Q., Wenbo, L., Tao, G.PGE geochemistry of carbonatites in Maoniuping REE deposit, Sichuan ProvinceGeochemical Journal, Vol. 37, 391-399.ChinaBlank
DS200412-0321
2003
Tao, G.Cheng, X., Zhilong, H.,Congqiang, L., Liang, Q., Wenbo, L., Tao, G.PGE geochemistry of carbonatites in Maoniuping REE deposit, Sichuan Province, China: preliminary study.Geochemical Journal, Vol. 37, 391-399.ChinaCarbonatite, geochemistry
DS200712-0133
2007
Tao, K.Campbell, L.S., Wall, F., Henderson, P., Zhang, P., Tao, K., Yang, Z.The character and context of zircons from the Bayan Obo Fe Nb REE deposit, Inner Mongolia.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 97-98.Asia, MongoliaCarbonatite
DS200712-0134
2007
Tao, K.Campbell, L.S., Wall, F., Henderson, P., Zhang, P., Tao, K., Yang, Z.The character and context of zircons from the Bayan Obo Fe Nb REE deposit, Inner Mongolia.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 97-98.Asia, MongoliaCarbonatite
DS200412-0533
2004
Tao, K-J.Fan, H-R., Xie, Yi-H., Wang, K-Y., Tao, K-J.REE daughter minerals trapped in fluid inclusions in the Giant Bayan Obo REE Nb Fe deposit, inner Mongolia, China.International Geology Review, Vol. 46, 8, pp. 638-645.China, MongoliaCarbonatite
DS200612-0305
2006
Tao, Ni.Daogong, C., Deloule, E., Tao, Ni.Metamorphic zircon from Xindian eclogite, Dabie Terrain: U Pb age and oxygen isotope composition.Science China Earth Sciences, Vol. 49, 1, Jan. pp. 66-76.ChinaUHP - eclogite, Dabie Shan
DS201112-0318
2011
Tao, R.Fei, Y., Zhang, Chi., Tao, R.Efficient carbon leaching in silicate through fluid/melt migration and implications for diamond formation.Goldschmidt Conference 2011, abstract p.835.MantleRedox reaction
DS201705-0890
2017
Tao, R.Xu, C., Kynicky, J., Tao, R., Liu, X., Zhang, L., Pohanka, M., Song, W., Fei, Y.Recovery of an oxidized majorite inclusion from Earth's deep asthenosphere.Science Advances, Vol. 3, 4, e1601589MantleEclogite

Abstract: Minerals recovered from the deep mantle provide a rare glimpse into deep Earth processes. We report the first discovery of ferric iron-rich majoritic garnet found as inclusions in a host garnet within an eclogite xenolith originating in the deep mantle. The composition of the host garnet indicates an ultrahigh-pressure metamorphic origin, probably at a depth of ~200 km. More importantly, the ferric iron-rich majoritic garnet inclusions show a much deeper origin, at least at a depth of 380 km. The majoritic nature of the inclusions is confirmed by mineral chemistry, x-ray diffraction, and Raman spectroscopy, and their depth of origin is constrained by a new experimental calibration. The unique relationship between the majoritic inclusions and their host garnet has important implications for mantle dynamics within the deep asthenosphere. The high ferric iron content of the inclusions provides insights into the oxidation state of the deep upper mantle.
DS201803-0481
2018
Tao, R.Tao, R., Fei, Y., Bullock, E.S., Xu, C., Zhang, L.Experimental investigation of Fe3+ rich majoritic garnet and its effect on majorite geobarometer.Geochimica et Cosmochimica Acta, Vol. 225, pp. 1-16.Technologygeobarometry

Abstract: Majoritic garnet [(Ca, Mg, Fe2+)3(Fe3+, Al, Si)2(SiO4)3] is one of the predominant and important constituents of upper mantle peridotite and ultra-deep subducted slabs. Majoritic substitution in garnet depends on pressure, and it has been used to estimate the formation pressure of natural majoritic garnet. Ferric iron (Fe3+) substitution occurs in natural majoritic garnets from mantle diamonds and shocked meteorites. However, available majorite geobarometers were developed without considering the effect of Fe3+ substitution in the structure. In this study, we systematically synthesized Fe3+- bearing majoritic garnets from 6.5?GPa to 15?GPa to evaluate the effect of Fe3+ on the majorite geobarometer. The Fe3+ contents of synthetic majoritic garnets were analyzed using the "Flank method" with the electron probe microanalyzer (EPMA). The results were compared with those based on the charge balance calculations. From the known synthesis pressures and measured Fe3+ contents, we developed a new majorite geobarometer for Fe3+-bearing majoritic garnets. Our results show that the existing majorite geobarometer, which does not take into account the Fe3+ substitution, could underestimate the formation pressure of majoritic garnets, especially for samples with a high majoritic component.
DS200812-0210
2008
Tao, W.Chen, L., Tao, W., Zhao, L., Zheng, T.Distinct lateral variation of lithospheric thickness in the northeastern North Chin a craton.Earth and Planetary Science Letters, Vol. 267, 1-2, pp. 56-68.ChinaTectonics
DS1992-1518
1992
Tao, W.C.Tao, W.C., O'Connell, R.J.Ablative subduction: a two sided alternative to the conventional subductionmodelJournal of Geophysical Research, Vol. 97, No. B6, June 10, pp. 8877-8904GlobalSubduction, Plate tectonics
DS1993-1571
1993
Tao, W.C.Tao, W.C., O'Connell, R.J.Deformation of a weak subducted slab and variation of seismicity at depthNature, Vol. 361, No. 6413, February 18, pp. 626-628GlobalTectonics, Mantle, Geophysics -seismics
DS201312-0806
2012
Tao, Y.Shen, A.H., Bassett, W.A., Skalwold, E.A., Fan, N.J., Tao, Y.Precision measurement of interfacet angles on faceted gems using a goniometer.Gems & Gemology, Vol. 48, spring pp. 32-38.TechnologyDiamond reference cut stones
DS201808-1780
2018
Tao, Y.Putirka, K., Tao, Y., Hari, K.R., Perfit, M., Jackson, M.G., Arevalo, Jr. R.The mantle source of thermal plumes: trace and minor element & major oxides of primitive liquids ( and why olivine compositions don't matter).minoscam.org, doi.org/10.2138/am-2018-6192 59p.Mantleforsterite

Abstract: We estimate the mantle source compositions for mantle plumes, and by implication Earth’s lower mantle, by: (a) measuring trace (e.g, Sc, V, Cu) and minor (e.g., Ca, Mn, Ni) element concentrations of high forsterite olivine grains from several plume localities, (b) estimating the parent liquid compositions from which they crystallized, (c) calculating mantle potential temperatures and degrees of partial melting and (d) estimating trace element compositions of depleted and enriched mantle sources. Our sample set includes two continental flood basalt provinces (Emeishan and Deccan), a flood basalt that erupted in a continental rift setting (Baffin Island), our type example of a thermal mantle plume (Hawaii) and lavas from the Siqueiros Transform at the East Pacific Rise, which represent the mid-ocean ridge system. We also present olivine compositions for the peridotite xenoliths from Kilbourne Hole, New Mexico, USA, which are commonly used as primary and secondary analytical standards. We find that trace elements in lava-hosted olivine grains are too far removed from their mantle source to provided anything but greatly hindered views of such. Olivine compositions reflect not only evolving liquid compositions (including partial melting conditions and later fractionation), but also evolving Ol+liq partition coefficients, which mostly increase with decreasing T during crystallization. Mantle compositions, delimited by maximum forsterite contents and estimates of parental magmas (and experimentally determined partition coefficients) indicate that our selected plumes reflect some combination of (1) a depleted mantle source that is quite similar to that obtained by other methods, and (2) a variably enriched plume source that is more enriched than current estimates of pyrolite. The enriched plume mantle sources can be explained remarkably well as a mixture of subducted mid-ocean ridge basalt (MORB; Gale et al. 2013) and depleted MORB mantle (DM; Salters and Stracke 2004), with MORB:DM ratios of 1:5 to 1:4. These ratios are most sensitive to estimates of melt fraction where plume parental magmas are last equilibrated with their mantle source, but are nonetheless consistent across a wide range of chemically very different elements, and estimates of MORB and DM obtained by very different means. Baffin Island is of particular interest. Like prior studies, we verify a high mantle potential temperature (Tp) of 1630oC (compared to Tp = 1320-1420oC for MORB from Cottrell and Kelley 2011 for Ol of Fo89.3-91.4). The Baffin source is also within error the same as DM with respect to trace elements, although still isotopically distinct; Baffin appears to be sourced in something that is akin to DM that lies at the base of the mantle, where plumes acquire their excess heat. Thus while part of our analysis supports the concept of a "slab graveyard" at the bottom of the lower mantle (e.g., Wyession 1996), that cemetery is by no means ubiquitous at the CMB: subducted slabs are either unevenly interred, or efficiently excavated by later upwellings.
DS1990-1443
1990
Tao WeipingTao WeipingNon-metallic mineral deposits of Chin a and plate tectonicsChina Earth Sciences, Vol. 1, No. 2, pp. 110-122ChinaPlate tectonics, Non-diamonds
DS1990-1444
1990
Tao WeipingTao WeipingThe minerogenic series of nonmetallic mineral deposits of ChinaActa Geologica Sinica, Vol. 3, No. 2, June pp. 164-178ChinaUltramafics, Genesis -nonmetallic deposits
DS1991-1692
1991
Tao ZhengzhanTao ZhengzhanOn the origin of the carat as the unit of weight for gemstones. *CHI?Chinese Journal of Geochemistry, *CHI, Vol. 10, No. 3, July-Sept. pp. 288-GlobalCarat weight, History
DS2002-1578
2002
Tapani, O.Tapani, O., Calzia, J.P., Kosunen, P.J.Geochemistry of Mesozoic plutons, southern Death Valley region: insights into origin of Cordilleran magmatismContribution to Mineralogy and Petrology, CaliforniaMagmatism
DS2002-1237
2002
TapaniRamoPedersen, S. Craig, Upton, TapaniRamo, Jepsen, KalsbeekPaleoproterozoic (1740 Ma) rift related volcanism in the Hekla Sund region, field occurrence, geochemistryPrecambrian Research, Vol. 114, No. 3-4, Mar.15, pp.327-46.Greenland, eastern northTectonics
DS1988-0324
1988
Tapi, R.D.Jain, Ajai Kumar, Tapi, R.D.Study of carbonatite in the northeast of BarwahDistrict, Khargone, SOURCE[ Vijana Parshad Anusandhan Patrike, (Ind)Vijana Parshad Anusandhan Patrike, (Ind), Vol. 31, No. 2-3, June pp. 89-96IndiaCarbonatite
DS200812-0088
2008
Tapia, M.T.F.Bastida, J.A.H., Tapia, M.T.F., Linares, A.A.Heavy metal content distribution and toxicity risks in soils developed from lamproitic rocks in Murcia, SE Spain.Advances in Geoecology, Vol. 36, pp. 493-500.Europe, SpainLamproite
DS1985-0661
1985
Tapley, I.J.Tapley, I.J., Wilson, P.The discrimination of potentially economic paleodrainage systems in the sedimentary basins of central and western Australia using NOA AVHRR imageryIn: Proceedings of the International Symposium on remote sensing of the environment, pp. 585-600AustraliaBlank
DS1988-0684
1988
Tapley, I.J.Tapley, I.J.The reconstruction of paleodrainage and regional geologic structures in Australias Canning and Officer Basins using NOAA- AVHRR Satellite imageryEarth Science Reviews, Vol. 25, No. 5-6, December pp. 409-425AustraliaPaleodrainage
DS200412-1962
2004
Taplin, R.Taplin, R., Snyman, M.Doing business in South Africa's new mining environment: a legal perspective.Canadian Institute of Mining and Metallurgy Bulletin, Vol. 97, 1078, March pp. 91-98.Africa, South AfricaLegal - royalty
DS200512-1069
2004
Taplin, R.Taplin, R., Isaac, T.Comments on Canada's National Diamond Strategy.Journal of Energy and Natural Resources Law, Vol. 22, 4, pp. 429-449. Ingenta 1045638748Canada, Northwest TerritoriesNews item - legal
DS201212-0338
2012
Tappe, K.Januszcak, M.H., Seller, S., Kurzlaukis, C., Murphy, J., Delgaty, S., Tappe, K., Ali, J.Zhu, Ellemers, P.A multidisciplinary approach to the Attawapiskat kimberlite field, Canada Canada: accelerating the discovery to production pipeline.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Ontario, AttawapiskatDeposit - Victor
DS2003-1358
2003
Tappe, S.Tappe, S., Foley, S.F., Jenner, G.A., Ryan, B., Besserer, D., Kjarsgaard, B.A.Ultramafic lamprophyre dykes from Labrador and New Quebec: mineralogy and8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractQuebec, LabradorKimberlite petrogenesis
DS200412-1963
2003
Tappe, S.Tappe, S., Foley, S.F., Jenner, G.A., Ryan, B.,Besserer, D., Kjarsgaard, B.A.Ultramafic lamprophyre dykes from Labrador and New Quebec: mineralogy and geochemistry.8 IKC Program, Session 7, AbstractCanada, Quebec, LabradorKimberlite petrogenesis
DS200512-1070
2004
Tappe, S.Tappe, S.Mesozoic mafic alkaline magmatism of southern Scandinavia.Contributions to Mineralogy and Petrology, Vol. 148, 3, pp. 312-Europe, ScandinaviaMagmatism
DS200512-1071
2005
Tappe, S.Tappe, S., Foley, S.F., Jenner, G.A., Kjarsgaard, B.A.Integrating ultramafic lamprophyres into the IUGS classification of igneous rocks: rationale and implications.Journal of Petrology, Vol. 46, 9, Sept. pp. 1893-1900.Classification - lamprophyres
DS200512-1072
2003
Tappe, S.Tappe, S., Foley, S.F., Pearson, D.G.African type kamafugites: a mineralogical and geochemical comparison with their Italian and Brazilian analogues.Periodico di Mineralogia, (in english), Vol. LXX11, 1. April, pp. 51-77.South America, Brazil, Africa, UgandaMelilite, katsilite, Toro Ankole Rift
DS200612-1178
2006
Tappe, S.Rosenthal, A., Foley, S.F., Pearson, G.D., Nowell, G., Tappe, S.Ugand an kamafugites: re-melting of a variable enriched veined subcontinental lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 26, abstract only.Africa, UgandaGeochemistry - melting
DS200612-1411
2006
Tappe, S.Tappe, S., Foley, S.F., Jenner, G.A., Heaman, L.M., Kjarsgaard, B.A., Romer,R.L., Stracke, A., Joyce, HoefsGenesis of ultramafic lamprophyres and carbonatites at Aillik Bay, Labrador: a consequence of incipient lithospheric thinning beneath the North Atlantic CratonJournal of Petrology, Vol. 47,7, pp. 1261-1315.Canada, LabradorCarbonatite
DS200712-1036
2007
Tappe, S.Steenfelt, A., Neilsen, T.D.F., Sand, K.K., Secher, K.,Tappe, S.Kimberlites, ultramafic lamprophyres and carbonatites in west Greenland - an update on occurrences, ages and diamonds.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, Volume 32, 1 pg. abstract p.79.Europe, GreenlandGeochronology
DS200712-1068
2007
Tappe, S.Tappe, S., Foley, S.F., Heaman, L.M., Romer, R.E., Stracke, A., Kjarsgaard, B.A., Jenner, G.A.Interactions between carbonate magmas and MARID metasomes: the case of Diamondiferous aillikites from the Torngat Mountains, Canada.Plates, Plumes, and Paradigms, 1p. abstract p. A1003.Canada, LabradorAillikite, magmatism
DS200712-1069
2007
Tappe, S.Tappe, S., Foley, S.F., Stracke, A., Romer, R.L., Kjarsgaard, B.A., Heamna, L.M., Joyce, N.Craton reactivation on the Labrador sea margins 40Ar 39Ar age and Sr Nd Hf Pb isotope constraints from alkaline and carbonatite intrusives.Earth and Planetary Science Letters, Vol. 256, 3-4, pp. 433-454.CanadaCarbonatite
DS200812-0577
2008
Tappe, S.Kjarsgaard, B.A., Pearson, D.G., Tappe, S., Nowell, G.M., Dowall, D.P.Kimberlites: high H2O/CO2, MgO rich and K poor silica undersaturated magmas. Lac de Gras9IKC.com, 3p. extended abstractAfrica, South Africa, Canada, Northwest TerritoriesGroup 1 kimberlites
DS200812-0971
2008
Tappe, S.Rosenthal, A., Foley, S.F., Pearson, D.G., Nowell, G.M., Tappe, S.Origin of kamafugite magmas in the East African Rift of western Uganda.9IKC.com, 3p. extended abstractAfrica, UgandaToro Ankole volcanic field
DS200812-1151
2008
Tappe, S.Tappe, S.Alkaline and carbonatite intrusives help to unravel the temporal evolution of a cratonic rift in the North Atlantic region.Goldschmidt Conference 2008, Abstract p.A935.Canada, Labrador, Europe, GreenlandLamproite
DS200812-1152
2008
Tappe, S.Tappe, S., Foley, S.F., Kjarsgaard, B.A, Romer, R.L., Heaman, L.M., Stracke, A., Jenner, G.A.Origin of Diamondiferous Torngat ultramafic lamprophyres and the role of multiple MARID type and carbonatitic vein metasomatized cratonic mantle ...9IKC.com, 3p. extended abstractCanada, Quebec, LabradorGenesis of SiO2 poor potassic melts
DS200812-1153
2008
Tappe, S.Tappe, S., Foley, S.F., Kjarsgaard, B.A., Romer, R.L., Heaman, L.M., Stracke, A., Jenner, G.A.Between carbonatite and lamproite - Diamondiferous Torngat ultramafic lamprohyres formed by carbonate fluxed melting of cratonic Marid type metasomes.Geochimica et Cosmochimica Acta, Vol. 72, 13, pp. 3258-3286.Canada, Labrador, QuebecTorngat
DS200812-1154
2008
Tappe, S.Tappe, S., Steenfelt, A., Heaman, L.M., Romer, R.J., Simonetti, A., Muehlenbachs, K.The alleged carbonatitic kimberlitic melt continuum: contrary evidence from West Greenland.Goldschmidt Conference 2008, Abstract p.A934.Europe, GreenlandDeposit - Safartoq
DS200912-0385
2009
Tappe, S.Kjarsgaard, B.A., Pearson, D.G., Tappe, S., Nowell, G.M., Dowall, D.P.Geochemistry of hypabyssal kimberlites from Lac de Gras Canada: comparisons to global database and implications to the parent magma problem.Lithos, In press available, 49p.Canada, Northwest TerritoriesGeochemical - whole rock database
DS200912-0745
2009
Tappe, S.Tappe, S., Heaman, L.M., Romer, R.L., Steenfelt, A., Simonetti, A., Muehlenbach, K., Stracke, A.Quest for primary carbonatite melts beneath cratons: a West Greenland perspective.Goldschmidt Conference 2009, p. A1314 Abstract.Europe, GreenlandCarbonatite
DS200912-0746
2009
Tappe, S.Tappe, S., Heaman, L.M., Smart, K.A., Muehlenbachs, K., Simonetti, A.First results from Greenland eclogite xenoliths: evidence for an ultra depleted peridotitic component within the North Atlantic craton mantle lithosphere.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyEurope, GreenlandMelting
DS200912-0747
2009
Tappe, S.Tappe, S., Sleenfelt, A., Heaman, L.M., Simonetti, A.The newly discovered Jurassic Tikusaaq carbonatite allikite occurrence, West Greenland, and some remarks on carbonatite kimberlite relationships.Lithos, in press availableEurope, GreenlandPetrology
DS201012-0510
2009
Tappe, S.Mitchell, R.H., Tappe, S.Discussion of 'Kimberlites and ailikites as probes of the continental lithospheric mantle by D. Francis and M. Patterson.Lithos, Available in press formated 14p.GlobalKimberlite
DS201012-0778
2010
Tappe, S.Tappe, S., Heaman, L.M.Can alkaline magmatism destroy a craton? Lessons learned from the Greenland Labrador diamond province.International Dyke Conference Held Feb. 6, India, 1p. AbstractCanada, Labrador, Europe, GreenlandAlkaline rocks, magmatism
DS201012-0779
2010
Tappe, S.Tappe, S., Pearson, D.G., Heaman, L., Nowell, G., Milstead, P.Relative roles of cratonic lithosphere and asthenosphere in controlling kimberlitic magma compositions: Sr Nd Hf isotope evidence fromGoldschmidt 2010 abstracts, abstractEurope, Greenland, Canada, LabradorGeochronology
DS201112-0774
2011
Tappe, S.Pearson, D.G., Tappe, S., Smart, K.A., Mather, K.S., Dale, C.W., Kjarsgaard, B.A.Crust mantle links in cratons.Goldschmidt Conference 2011, abstract p.1610.MantleSlave, Kaapvaal, coupling -decoupling
DS201112-1028
2011
Tappe, S.Tappe, S., Pearson, D.G., Nowell, G., Nielsen, T., Milstead, P., Muehlenbachs, K.A fresh isotopic look at Greenland kimberlites: craton mantle lithosphere imprint on deep source signal.Earth and Planetary Science Letters, Vol. 305, 1-2, pp. 235-248.Europe, GreenlandGeochronology - convection
DS201112-1029
2011
Tappe, S.Tappe, S., Smart, K.A., Pearson, D.G., Steenfelt, A., Simonetti, A.Craton formation in late Archean subduction zones revealed by first Greenland eclogites.Geology, Vol. 39, 12, pp. 1103-1106.Europe, GreenlandMelting , Nunatak-1390
DS201212-0023
2012
Tappe, S.Armstrong, J.P., Fitzgerald, C., Kjarsgaard, B.A., Herman, L., Tappe, S.Kimberlites of the Coronation Gulf field, northern Slave Craton, Nunavut, Canada.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, NunavutDeposit - 26 kimberlites by name
DS201212-0320
2012
Tappe, S.Hunt, L., Stachel, T., Grutter, H., Armstrong, J., McCandless, T.E., Simonetti, A., Tappe, S.Small mantle fragments from the Renard kimberlites, Quebec: powerful recorders of mantle lithosphere formation and modification beneath the eastern Superior Craton.Journal of Petrology, Vol. 53, 8, pp. 1597-1635.Canada, QuebecDeposit - Renard
DS201212-0668
2012
Tappe, S.Smart, K.A., Chacko, T., Stachel, T., Tappe, S., Muehlenbachs, K., Ickert, R.B., Stern, R.A.Jericho eclogite formation revealed by diamond inclusions: oceanic origin without crustal signature?10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, NunavutDeposit - Jericho
DS201212-0669
2012
Tappe, S.Smart, K.A., Chacko, T., Stachel, T., Tappe, S., Stern, R.A., Ickert, R.B.Eclogite formation beneath the northern Slave Craton constrained by diamond inclusions: oceanic lithosphere origin without a crustal signature.Earth and Planetary Science Letters, Vol. 319-320, pp. 165-177.Canada, Northwest TerritoriesDiamond inclusions
DS201212-0718
2012
Tappe, S.Tappe, S., Nowell, G.M., Kurszlaukis, S., Kjarsgaard, B.A.Large igneous provinces and kimberlites? Origin of the Diamondiferous Amon kimberlites, Baffin Island, Arctic Canada.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Nunavut, Baffin IslandDeposit - Amon
DS201212-0719
2012
Tappe, S.Tappe, S., Simonetti, A.Combined U-Pb geochronology and Sr-Nd isotope analysis of the Ice River perovskite standard, with implications for kimberlite and alkaline rock petrogenesis.Chemical Geology, Vol. 304-305, pp. 10-17.TechnologyGeochronology
DS201212-0720
2012
Tappe, S.Tappe, S., Smart, K.A., Stracke, A., Romer, R.L., Steenfelt, A., Muehlenbachs, K.Carbon fluxes beneath cratons: insights from West Greenland kimberlites and carbonatites.Goldschmidt Conference 2012, abstract 1p.Europe, GreenlandMelting
DS201212-0721
2012
Tappe, S.Tappe, S., Steenfelt, A., Nielsen, T.Astheospheric source of Neoproterozoic and Mesozoic kimberlites from the North Atlantic craton, West Greenland: new high precision U-Pb and Sr-Nd isotope dat a on perovskite.Chemical Geology, Vol. 320-321, pp. 113-127.Europe, GreenlandGeochronology
DS201312-0078
2013
Tappe, S.Beyer, C., Berndt, J., Tappe, S., Klemme, S.Trace element partioning between perovskites and kimberlite to carbonatite melt: new experimental constraints.Chemical Geology, Vol. 353, pp. 132-139.MantleAlkaline rocks, magmatism
DS201312-0223
2013
Tappe, S.Donatti-Filho, J.P., Tappe, S., Oliveira, E.P., Heaman, L.M.Age and origin of Neoproterozoic Brauna kimberlitic melt generation with the metasomatized base of Sao Francisco craton, BrazilChemical Geology, Vol. 353, pp. 19-35.South America, BrazilGeochronology, geochemistry (kimberlites and orangeites)
DS201312-0901
2013
Tappe, S.Tappe, S., Pearson, D.G., Kjarsgaard, B.A., Nowell, G., Dowall, D.Mantle transition zone input to kimberlite magmatism near a subduction zone: origin of anomalous Nd-Hf isotope systematics at Lac de Gras, Canada.Earth and Planetary Science Letters, Vol. 371-372, pp. 235-251.Canada, Northwest TerritoriesGeochronology, convection
DS201312-0903
2013
Tappe, S.Tappe, S., Pearson, D.G., Kjarsgaard, B.A., Nowell, G.M., Dowall, D.Linking kimberlite magmatism, transition zone diamonds, and subduction processes.Goldschmidt 2013, AbstractMantleSubduction
DS201312-0904
2013
Tappe, S.Tappe, S., Pearson, D.G., Prelevic, D.Kimberlite, carbonatite, and potassic magmatism as part of the geochemical cycle.Chemical Geology, Vol. 353, pp. 1-3 intro.MantleMelting, recyle
DS201412-0424
2013
Tappe, S.Januszczak, N., Seller, M.H., Kurzlaukis, S., Murphy, C., Delgaty, J., Tappe, S., Ali, K., Zhu, J., Ellemers, P.A multidisciplinary approach to the Attwapiskat kimberlite field, Canada: accelerating the discovery-to-production pipeline.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 157-172.Canada, Ontario, AttawapiskatDeposit - Victor area
DS201412-0428
2014
Tappe, S.Jelsma, H., Tappe, S.Kimberlites and supercontinent cyclicity.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 12, title onlyGlobalKimberlite genesis
DS201412-0897
2014
Tappe, S.Sun, J., Liu, C-Z., Tappe, S., Kostrovitsky, S.I., Wu, F-Y., Yakovlev, D., Yang, Y-H., Yang, J-H.Repeated kimberlite magmatism beneath Yakutia and its relationship to Siberian flood volcanism: insights from in situ U-Pb and Sr-Nd perovskite isotope analysis.Earth and Planetary Science Letters, Vol. 404, Oct. pp. 283-295.Russia, YakutiaKimberlite magmatism
DS201412-0915
2014
Tappe, S.Tappe, S.Carbon fluxes beneath cratons: insights from Greenland kimberlites, carbonatites and diamonds.ima2014.co.za, AbstractEurope, GreenlandKimberlite
DS201412-0916
2014
Tappe, S.Tappe, S., Kjarsgaard, B., Aulbach, S.Mantle carbon mobilization during supercontinent break up: evidence from kimberlites and their diamonds.Goldschmidt Conference 2014, 1p. AbstractMantleCarbon
DS201412-0917
2014
Tappe, S.Tappe, S., Kjarsgaard, B.A., Kurszlaukis, S., Nowell, G.M., Phillips, D.Petrology and Nd-Hf isotope geochemistry of the Neoproterozoic Amon kimberlite sills, Baffin Island ( Canada): evidence of deep mantle magmatic activity linked to Supercontinent cycles.Journal of Petrology, Vol. 55, 10, pp. 2003-2042.Canada, Nunavut, Baffin IslandDeposit - Amon sills
DS201512-1976
2016
Tappe, S.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
DS201602-0239
2016
Tappe, S.Smart, K.A., Tappe, S., Stern, R.A., Webb, S.J., Ashwal, L.D.Early Archean tectonics and mantle redox recorded in Witwatersrand diamonds.Nature Geoscience, Online, Jan. 11, 6p.Africa, South AfricaPlacer diamonds

Abstract: Plate tectonics plays a vital role in the evolution of our planet. Geochemical analysis of Earth’s oldest continental crust suggests that subduction may have begun episodically about 3.8 to 3.2 billion years ago, during the early Archaean or perhaps more than 3.8 billion years ago, during the Hadean. Yet, mantle rocks record evidence for modern-style plate tectonics beginning only in the late Archaean, about 3 billion years ago. Here we analyse the nitrogen abundance, as well as the nitrogen and carbon isotopic signatures of Archaean placer diamonds from the Kaapvaal craton, South Africa, which formed in the upper mantle 3.1 to 3.5 billion years ago. We find that the diamonds have enriched nitrogen contents and isotopic compositions compared with typical mantle values. This nitrogen geochemical fingerprint could have been caused by contamination of the mantle by nitrogen-rich Archaean sediments. Furthermore, the carbon isotopic signature suggests that the diamonds formed by reduction of an oxidized fluid or melt. Assuming that the Archaean mantle was more reduced than the modern mantle, we argue that the oxidized components were introduced to the mantle by crustal recycling at subduction zones. We conclude, on the basis of evidence from mantle-derived diamonds, that modern-style plate tectonics operated as early as 3.5 billion years ago.
DS201602-0244
2016
Tappe, S.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; eNdi = +4.4 to +5.2; eHfi = +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 (eHfi = +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 (eHfi = +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; eNdi = +2.0 to +3.1; eHfi = +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.
DS201607-1380
2016
Tappe, S.Tappe, S.India's fast Mesozoic drift linked to continental mantle lithosphere delamination: new insights from (U-Th)/He thermochronology of Dharwar craton kimberlites.IGC 35th., Session A Dynamic Earth 1p. AbstractIndiaKimberlite
DS201607-1381
2016
Tappe, S.Tappe, S., Griffin, W., Janney, P., Arndt, N., Gurney, J.The dynamic Earth and its kimberlite, cratonic mantle and diamond record through time.IGC 35th., Session A Dynamic Earth 1p. AbstractMantleKimberlite
DS201609-1748
2016
Tappe, S.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; eNdi = + 0.2 to + 4.8; eHfi = + 0.3 to + 6.5; d13C = - 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.
DS201611-2141
2016
Tappe, S.Smart, K., Tappe, S., Simonetti, A., Harris, C.Tectonic significance and redox state of Paleoproterozoic eclogite and pyroxenite components in the Slave cratonic mantle lithosphere, Voyageur kimberlite, Arctic Canada.Chemical Geology, in press available 22p.Canada, NunavutDeposit - Voyageur
DS201612-2341
2016
Tappe, S.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; eNdi = + 0.2 to + 4.8; eHfi = + 0.3 to + 6.5; d13C = - 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.
DS201705-0874
2017
Tappe, S.Smart, K.A., Cartigny, P., Tappe, S., O'Brien, H., Klemme, S.Lithospheric diamond formation as a consequence of methane rich volatile flooding: an example from Diamondiferous eclogite xenoliths of the Karelian craton ( Finland).Geochimica et Cosmochimica Acta, Vol. 206, pp. 312-342.Europe, FinlandDeposit - Lahtojoki

Abstract: A collection of 61 xenocrystic and 12 eclogite xenolith-derived diamonds from the 600 Ma Lahtojoki kimberlite in central Finland has been investigated. Calculated pressure and temperature conditions for the diamondiferous eclogites are in excess of 5.5 GPa and 1300 °C, suggesting residence depths greater than 180 km, near the base of the Karelian cratonic mantle lithosphere. Geochemically, the eclogite xenoliths have gabbroic compositions showing positive Eu and Sr anomalies, relatively low SREE and elevated Al2O3 contents, yet garnets have ambiguous d18O values of 5.7‰ and 5.9‰. Gabbroic eclogite formation could therefore be linked to either subduction processes during the 1.9 Ga Svecofennian orogeny or to cumulate processes during 2.1 Ga rift-induced magmatism. Determination of the oxygen fugacity of Lahtojoki eclogite xenoliths from both this work and previous studies suggests that diamond-bearing eclogites may be more reduced (?FMQ-3.5) compared to barren eclogites (?FMQ-1.7). While recycled oceanic crust protoliths for the eclogites remain a possibility, the carbon isotopic compositions and nitrogen abundances of the Lahtojoki diamonds indicate mantle-derived volatile sources. All diamonds (i.e., loose and eclogite xenolith-derived) display a restricted range of d13C values from -7.8‰ to -3.7‰ that overlaps with the carbon isotopic composition of Earth’s mantle. The Lahtojoki diamond d13C values form a negatively skewed distribution, indicating diamond growth from reduced mantle-derived carbon sources such as methane- (CH4) bearing fluids. Nitrogen contents of the Lahtojoki diamonds range from 40 to 1830 atomic ppm with a mean of ~670 atomic ppm; these elevated nitrogen contents combined with the close association to eclogites suggest an eclogitic or crustal volatile source. However, the Karelian craton was periodically intruded by ultramafic alkaline magmas since at least 1.8 Ga, noting in particular the occurrence of phlogopite-rich kimberlites and olivine lamproites between 1200 and 700 Ma. We argue that this punctuated volatile-rich magmatism simultaneously metasomatised the cratonic mantle lithosphere, forming nitrogen enriched phlogopite-bearing metasomes. We propose that reduced, carbon-bearing and nitrogen-rich fluids were remobilized to form the Lahtojoki diamonds. The diamond-forming event(s) most probably occurred during or shortly prior to the entraining kimberlite magmatism as indicated by the diamond nitrogen aggregation systematics. Involvement of reduced diamond-forming fluids is supported by both the negative skewness of Lahtojoki diamond d13C values and the more reduced nature of the diamondiferous Lahtojoki eclogites compared with their more oxidized barren counterparts. Our results from the diamondiferous eclogites derived from the deepest parts of the Karelian cratonic mantle root are in support of methane being the stable carbon volatile species at the base of thick continental lithosphere.
DS201705-0882
2017
Tappe, S.Tappe, S., Romer, R.L., Stracke, A., Steenfelt, A., Smart, K.A., Muehlenbachs, K., Torsvik, T.H.Sources and mobility of carbonate melts beneath cratons, with implications for deep carbon cycling, metasomatism and rift initiation.Earth and Planetary science Letters, Vol. 466, pp. 152-167.MantleMetasomatism, magma, carbonatite

Abstract: Kimberlite and carbonatite magmas that intrude cratonic lithosphere are among the deepest probes of the terrestrial carbon cycle. Their co-existence on thick continental shields is commonly attributed to continuous partial melting sequences of carbonated peridotite at >150 km depths, possibly as deep as the mantle transition zone. At Tikiusaaq on the North Atlantic craton in West Greenland, approximately 160 Ma old ultrafresh kimberlite dykes and carbonatite sheets provide a rare opportunity to study the origin and evolution of carbonate-rich melts beneath cratons. Although their Sr-Nd-Hf-Pb-Li isotopic compositions suggest a common convecting upper mantle source that includes depleted and recycled oceanic crust components (e.g., negative ?eHf?eHf coupled with View the MathML source>+5‰d7Li), incompatible trace element modelling identifies only the kimberlites as near-primary low-degree partial melts (0.05-3%) of carbonated peridotite. In contrast, the trace element systematics of the carbonatites are difficult to reproduce by partial melting of carbonated peridotite, and the heavy carbon isotopic signatures (-3.6 to View the MathML source-2.4‰d13C for carbonatites versus -5.7 to View the MathML source-3.6‰d13C for kimberlites) require open-system fractionation at magmatic temperatures. Given that the oxidation state of Earth's mantle at >150 km depth is too reduced to enable larger volumes of ‘pure’ carbonate melt to migrate, it is reasonable to speculate that percolating near-solidus melts of carbonated peridotite must be silicate-dominated with only dilute carbonate contents, similar to the Tikiusaaq kimberlite compositions (e.g., 16-33 wt.% SiO2). This concept is supported by our findings from the North Atlantic craton where kimberlite and other deeply derived carbonated silicate melts, such as aillikites, exsolve their carbonate components within the shallow lithosphere en route to the Earth's surface, thereby producing carbonatite magmas. The relative abundances of trace elements of such highly differentiated ‘cratonic carbonatites’ have only little in common with those of metasomatic agents that act on the deeper lithosphere. Consequently, carbonatite trace element systematics should only be used with caution when constraining carbon mobility and metasomatism at mantle depths. Regardless of the exact nature of carbonate-bearing melts within the mantle lithosphere, they play an important role in enrichment processes, thereby decreasing the stability of buoyant cratons and promoting rift initiation - as exemplified by the Mesozoic-Cenozoic breakup of the North Atlantic craton.
DS201707-1328
2017
Tappe, S.Giuliani, A.M., Tappe, S., Rooney, T.O., McCoy-West, A.J., Yaxley, G.M., Mezger, K.Editorial: the role of intraplate magmas and their inclusions in Earth's mantle evolution.Chemical Geology, Vol. 455, pp. 1-5.Mantlemagmatism

Abstract: Carbon isotope compositions and the distribution of nitrogen and hydrogen in diamonds from 18 eclogites from Nurbinskaya kimberlites were studied in situ in polished plates. Cathodoluminescence images show that most of the diamonds have complex growth structures with distinctive cores, intermediate and rim zones. In some diamonds the cores display dissolution features, and intermediate growth zones are separated from the cores by narrow rounded oscillatory zones. At least three crystals show interrupted multistage diamond growth; variations in d ¹³C of 2–3‰ occur across the contacts between distinct zones. Generally, d¹³C within the diamond cores varies only by 1–2‰, in rare cases up to 3.3‰. d¹³C values are usually lower in the intermediate zones and drop further towards the rims by up to 3‰. High-resolution SIMS profiles show that variations in d¹³C across the diamond growth zones are sharp with no evidence of diffusive relaxation.
DS201707-1369
2017
Tappe, S.Smart, K.A., Tappe, S., Simonetti, A., Simonetti, S.S., Woodland, A.B., Harris, C.Tectonic significance and redox state of Paleoproterozoic eclogite and pyroxenite components in the Slave cratonic mantle lithosphere, Voyager kimberlite, Arctic Canada.Chemical Geology, Vol. 455, pp. 98-119.Canadadeposit - Voyager

Abstract: Mantle-derived eclogite and pyroxenite xenoliths from the Jurassic Voyageur kimberlite on the northern Slave craton in Arctic Canada were studied for garnet and clinopyroxene major and trace element compositions, clinopyroxene Pb and garnet O isotopic compositions, and garnet Fe3 +/SFe contents. The Voyageur xenoliths record a wide range of pressures, but are cooler compared to mantle xenoliths derived from the nearby, coeval Jericho kimberlite. The CaO, TiO2 and Zr contents of Voyageur eclogites increase with depth, which is also observed in northern Slave peridotite xenoliths, demonstrating ‘bottom-up’ metasomatic processes within cratonic mantle lithosphere. The Voyageur eclogites have positive Eu anomalies, flat HREEN patterns, and major element compositions that are consistent with ultimate origins from basaltic and gabbroic protoliths within oceanic lithosphere. Clinopyroxene Pb isotope ratios intercept the Stacey-Kramers two-stage terrestrial Pb evolution curve at ca. 2.1 Ga, and form an array towards the host kimberlite, indicating isotopic mixing. The 2.1 Ga eclogite formation age broadly overlaps with known Paleoproterozoic subduction and collision events that occurred along the western margin of the Slave craton. Unlike the eclogites, the Voyageur pyroxenites contain garnet with distinctive fractionated HREEN, sinusoidal REE patterns of calculated bulk rocks, and clinopyroxene with 206Pb/204Pb ratios that intercept the Stacey-Kramers curve at 1.8 Ga. This suggests a distinct origin as Paleoproterozoic high-pressure mantle cumulates. However, the pyroxenite Pb isotope ratios fall within the eclogite array and could also be explained by protoliths formation at ca. 2.1 Ga followed by minor isotopic mixing during mantle metasomatism. Thus, an alternative scenario involves pyroxenite formation within the mantle section of Paleoproterozoic oceanic lithosphere followed by variable metasomatism after incorporation into cratonic mantle lithosphere. This model allows for a linked petrogenesis of the Voyageur eclogites (crust) and pyroxenites (mantle) as part of the same subducting oceanic slab. Oxygen fugacity determinations for one pyroxenite and ten eclogite xenoliths show a range of 3 log units, from - 4.6 to - 1.6 ?FMQ, similar to the range observed for nearby Jericho and Muskox eclogites (?FMQ - 4.2 to - 1.5). Importantly, the northern Slave eclogite and pyroxenite mantle components are highly heterogeneous in terms of redox state provided that they range from reduced to oxidized relative to Slave peridotite xenoliths. Moreover, the Voyageur eclogites do not exhibit any trend between oxidation state and equilibration depth, which contrasts with the downward decrease in fO2 shown by Slave and worldwide cratonic peridotite xenoliths. Our investigation of mantle eclogite and pyroxenite fO2 reinforces the important influence of recycled mafic components in upper mantle processes, because their high and variable redox buffering capacity strongly controls volatile speciation and melting relations under upper mantle conditions.
DS201707-1375
2017
Tappe, S.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; eNdi = + 0.2 to + 4.8; eHfi = + 0.3 to + 6.5; d13C = - 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.
DS201708-1774
2017
Tappe, S.Tappe, S.Evolution of kimberlite magmatism on the dynamic Earth.11th. International Kimberlite Conference, OralMantlemagmatism
DS201709-2054
2017
Tappe, S.Smart, K., Tappe, S., Simonetti, A., Simonetti, S., Woodland, A., Harris, C.The redox state of mantle eclogites.Goldschmidt Conference, abstract 1p.Mantleeclogites

Abstract: Mantle-derived eclogite xenoliths are key for studying the evolution of the cratonic lithosphere, because geochemical evidence suggests that they typically represent fragments of Archean and Proterozoic oceanic lithosphere [1]. Recently, it has been suggested that eclogite xenoliths can serve as redox sensors of the Precambrian upper mantle using V/Sc as a redox proxy [2]. However, metasomatism can change the original oxidation state of the cratonic mantle [3], thereby limiting its use for monitoring mantle redox evolution. Circa 1.8–2.2 Ga eclogite xenoliths erupted with Jurassic kimberlites of the northern Slave craton have geochemical features that indicate oceanic crust protoliths [4, 5]. Such Paleoproterozoic ages are common for Slave craton mantle eclogites [6], linking eclogite formation with 1.9 Ga subduction-collision events at the western craton margin. The eclogites studied here have highly variable Fe3+/SFe (0.019 – 0.076 ±0.01), with logfO2 (?FMQ-4 to +2 ±0.5) that are both relatively oxidized and reduced compared to Slave mantle peridotite xenoliths [3]. Also, eclogite fO2 positively correlates with some indicies of metasomatism, such as elevated TiO2 in garnet. In addition to considering the time gap between eclogite formation and kimberlite eruption, the highly variable fO2–depth systematics of the eclogites studied here illustrate the drawbacks of using averaged eclogite fO2 to define the redox evolution of the upper mantle. Despite this, the ca. 2 Ga northern Slave craton eclogites have an average depth-corrected logfO2 of ?FMQ-0.5±1.3 (1s) that overlaps with modern MORB, and complies with the upper mantle redox evolution trend predicted using V/Sc ratios of mantlederived melts [2]. However, given the debate around the secuarity of mantle redox [7], further research into the suitability of mantle eclogites as redox sensors is warranted.
DS201710-2218
2017
Tappe, S.Burness, S., Smart, K.A., Stevens, G., Tappe, S., Sharp, Z.D., Gibbons, J.S-bearing metasomatism of mantle eclogites: constraints from the Kaapvaal craton and experiments.Goldschmidt Conference, 1p. AbstractAfrica, South Africadeposit - Roberts Victor, Jagersfontein
DS201801-0070
2018
Tappe, S.Tappe, S., Smart, K., Torsvik, T., Massuyeau, M., de Wit, M.Geodynamics of kimberlites on a cooling Earth: clues to plate tectonic evolution and deep volatile cycles.Earth and Planetary Science Letters, Vol. 484, pp. 1-14.Mantlekimberlite, origin, magmatism

Abstract: Kimberlite magmatism has occurred in cratonic regions on every continent. The global age distribution suggests that this form of mantle melting has been more prominent after 1.2 Ga, and notably between 250-50 Ma, than during early Earth history before 2 Ga (i.e., the Paleoproterozoic and Archean). Although preservation bias has been discussed as a possible reason for the skewed kimberlite age distribution, new treatment of an updated global database suggests that the apparent secular evolution of kimberlite and related CO2-rich ultramafic magmatism is genuine and probably coupled to lowering temperatures of Earth's upper mantle through time. Incipient melting near the CO2- and H2O-bearing peridotite solidus at >200 km depth (1100-1400?°C) is the petrologically most feasible process that can produce high-MgO carbonated silicate melts with enriched trace element concentrations akin to kimberlites. These conditions occur within the convecting asthenospheric mantle directly beneath thick continental lithosphere. In this transient upper mantle source region, variable CHO volatile mixtures control melting of peridotite in the absence of heat anomalies so that low-degree carbonated silicate melts may be permanently present at ambient mantle temperatures below 1400?°C. However, extraction of low-volume melts to Earth's surface requires tectonic triggers. Abrupt changes in the speed and direction of plate motions, such as typified by the dynamics of supercontinent cycles, can be effective in the creation of lithospheric pathways aiding kimberlite magma ascent. Provided that CO2- and H2O-fluxed deep cratonic keels, which formed parts of larger drifting tectonic plates, existed by 3 Ga or even before, kimberlite volcanism could have been frequent during the Archean. However, we argue that frequent kimberlite magmatism had to await establishment of an incipient melting regime beneath the maturing continents, which only became significant after secular mantle cooling to below 1400?°C during post-Archean times, probably sometime shortly after 2 Ga. At around this time kimberlites replace komatiites as the hallmark mantle-derived magmatic feature of continental shields worldwide. The remarkable Mesozoic-Cenozoic ‘kimberlite bloom’ between 250-50 Ma may represent the ideal circumstance under which the relatively cool and volatile-fluxed cratonic roots of the Pangea supercontinent underwent significant tectonic disturbance. This created more than 60% of world's known kimberlites in a combination of redox- and decompression-related low-degree partial melting. Less than 2% of world's known kimberlites formed after 50 Ma, and the tectonic settings of rare ‘young’ kimberlites from eastern Africa and western North America demonstrate that far-field stresses on cratonic lithosphere enforced by either continental rifting or cold subduction play a crucial role in enabling kimberlite magma transfer to Earth's surface.
DS201802-0267
2018
Tappe, S.Sun, J., Tappe, S., Kostrovitsky, S.I., Liu, C-Z., Shuzovatv, S.Yu., Wu, F-Y.Mantle sources of kimberlites through time: a U Pb and Lu Hf isotope study of zircon megacrysts from the Siberian diamond fields.Chemical Geology, in press available, 39p. PdfRussia, Siberiadeposit - Mir, Udachnaya, Anabar alluvials, Ebelyakh placers

Abstract: A comprehensive, internally consistent U-Pb and Lu-Hf isotope data set for 93 mantle-derived zircons from the Yakutian kimberlite province confirms and further refines the four major episodes of kimberlite magmatism on the Siberian craton: 421-409?Ma (Late Silurian-Early Devonian), 358-353?Ma (Late Devonian-Early Carboniferous), 226-218?Ma (Late Triassic), and 161-144?Ma (Middle-Late Jurassic). The relatively narrow, constant range of eHf values between +2 and +10 for both the Paleozoic and Mesozoic mantle-derived zircons (and by inference kimberlites) suggests that the volatile-rich magmas were repeatedly sourced from the convecting upper mantle beneath the Siberian craton. This finding is in keeping with the narrow and constant range of eNd values for groundmass perovskites from the Yakutian kimberlite province between +1.8 and +5.5 between 420 and 150?Ma. Our preferred model implies that the convecting upper mantle beneath the Yakutian kimberlite province ‘recovered’ rapidly back to ambient conditions shortly after the giant plume-related flood volcanic event that produced the Siberian Traps at 250?Ma. Although close spatial relationships exist between kimberlites and flood basalts on the Siberian craton during both the Paleozoic and Mesozoic, exact timing of the igneous events and the isotopic compositions of the diverse deep-sourced melting products rule out any direct genetic links.Besides the highly economic kimberlite-hosted diamond deposits of Late Devonian age (e.g., Mir and Udachnaya), the Siberian craton also contains significant Mesozoic placer diamond deposits (e.g., along the Anabar river), for which lamproite sources have been suggested recently. Our study shows that mantle-derived zircon megacryst fragments from the Ebelyakh placer deposit have Late Triassic ages of ca. 224?Ma. Their long-term depleted Hf isotopic compositions (+8.5 eHf) suggest that the alluvial diamonds were sourced from asthenosphere-derived Triassic kimberlites rather than from lithospheric mantle derived isotopically enriched lamproites.
DS201803-0480
2018
Tappe, S.Sun, J., Tappe, S., Kostrovitsky, S.I., liu, C-Z., Skuzovatov, S.Y., Wu, F-Y.Mantle sources of kimberlites through time: A U-Pb and Lu-HF isotope study of zircon megacrysts from the Siberian diamond Fields.Chemical Geology, Vol. 479, pp. 228-240.Russia, Siberiageochronology

Abstract: A comprehensive, internally consistent U-Pb and Lu-Hf isotope data set for 93 mantle-derived zircons from the Yakutian kimberlite province confirms and further refines the four major episodes of kimberlite magmatism on the Siberian craton: 421-409?Ma (Late Silurian-Early Devonian), 358-353?Ma (Late Devonian-Early Carboniferous), 226-218?Ma (Late Triassic), and 161-144?Ma (Middle-Late Jurassic). The relatively narrow, constant range of eHf values between +2 and +10 for both the Paleozoic and Mesozoic mantle-derived zircons (and by inference kimberlites) suggests that the volatile-rich magmas were repeatedly sourced from the convecting upper mantle beneath the Siberian craton. This finding is in keeping with the narrow and constant range of eNd values for groundmass perovskites from the Yakutian kimberlite province between +1.8 and +5.5 between 420 and 150?Ma. Our preferred model implies that the convecting upper mantle beneath the Yakutian kimberlite province ‘recovered’ rapidly back to ambient conditions shortly after the giant plume-related flood volcanic event that produced the Siberian Traps at 250?Ma. Although close spatial relationships exist between kimberlites and flood basalts on the Siberian craton during both the Paleozoic and Mesozoic, exact timing of the igneous events and the isotopic compositions of the diverse deep-sourced melting products rule out any direct genetic links. Besides the highly economic kimberlite-hosted diamond deposits of Late Devonian age (e.g., Mir and Udachnaya), the Siberian craton also contains significant Mesozoic placer diamond deposits (e.g., along the Anabar river), for which lamproite sources have been suggested recently. Our study shows that mantle-derived zircon megacryst fragments from the Ebelyakh placer deposit have Late Triassic ages of ca. 224?Ma. Their long-term depleted Hf isotopic compositions (+8.5 eHf) suggest that the alluvial diamonds were sourced from asthenosphere-derived Triassic kimberlites rather than from lithospheric mantle derived isotopically enriched lamproites.
DS201805-0935
2017
Tappe, S.Aulbach, S., Sun, J., Tappe, S., Hofer, H.E., Gerdes, A.Volatile rich metasomatism in the cratonic mantle beneath SW Greenland: link to kimberlites and mid-lithospheric discontinuities.Journal of Petrology, Vol. 58, 12, pp. 2311-2338.Europe, Greenlandkimberlite

Abstract: The cratonic part of Greenland has been a hotspot of scientific investigation since the discovery of some of the oldest crust on Earth and of significant diamond potential in the underlying lithospheric mantle, the characterization of which remains, however, incomplete. We applied a detailed petrographic and in situ analytical approach to a new suite of fresh kimberlite-borne peridotite xenoliths, recovered from the North Atlantic craton in SW Greenland, to unravel the timing and nature of mantle metasomatism, and its link to the formation of low-volume melts (e.g. kimberlites) and to geophysically detectible discontinuities. Two types of mineralogies and metasomatic styles, occurring at two depth intervals, are recognized. The first type comprises lherzolites, harzburgites and dunites, some phlogopite-bearing, which occur from ~100-170?km depth. They form continuous trends towards lower mineral Mg# at increasing TiO2, MnO and Na2O and decreasing NiO contents. These systematics are ascribed to metasomatism by a hydrous silicate melt precursor to c. 150?Ma kimberlites, in the course of rifting, decompression and lithosphere thinning. This metasomatism was accompanied by progressive garnet breakdown, texturally evident by pyroxene-spinel assemblages occupying former coarse grains and compositionally evident by increasing concentrations of elements that are compatible in garnet (Y, Sc, In, heavy rare earth elements) in newly formed clinopyroxene. Concomitant sulphide saturation is indicated by depletion in Cu, Ni and Co. The residual, more silica-undersaturated and potentially more oxidizing melts percolated upwards and metasomatized the shallower lithospheric mantle, which is composed of phlogopite-bearing, texturally equilibrated peridotites, including wehrlites, showing evidence for recent pyroxene-breakdown. This is the second type of lithology, which occurs at ~90-110?km depth and is inferred to have highly depleted protoliths. This type is compositionally distinct from lherzolites, with olivine having higher Ca/Al, but lower Al and V contents. Whereas low Al may in part reflect lower equilibration temperatures, low V is ascribed to a combination of intrinsically more oxidizing mantle at lower pressure and oxidative metasomatism. The intense metasomatism in the shallow cratonic mantle lithosphere contrasts with the strong depletion recorded in the northwestern part of the craton, which at 590-550?Ma extended to >210?km depth, and suggests loss of ~40?km of lithospheric mantle, also recorded in the progressive shallowing of magma sources during the breakup of the North Atlantic craton. The concentration of phlogopite-rich lithologies in a narrow depth interval (~90-110?km) overlaps with a negative seismic velocity gradient that is interpreted as a mid-lithospheric discontinuity beneath western Greenland. This is suggested to be a manifestation of small-volume volatile-rich magmatism, which paved the way for Mesozoic kimberlite, ultramafic lamprophyre, and carbonatite emplacement across the North Atlantic craton.
DS201809-2047
2018
Tappe, S.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.
DS201809-2088
2018
Tappe, S.Smart, K.A., Cartigny, P., Tappe, S., O'Brien, H., Klemme, S.Reduced volatile sources for Karelian diamonds linked to punctuated ultramafic magmatism. LahtojokiGoldschmidt Conference, 1p. AbstractEurope, FinlandDeposit - Lahtojoki

Abstract: Diamond xenocrysts and eclogite-hosted diamonds from the Lahtojoki kimberlite (Karelian craton, Finland) indicate metasomatism of the deep lithosphere by N-rich, relatively reduced fluids. P-T-fO2 constraints show that all eclogites were derived from near the base of the lithospheric mantle (>5 GPa), but only the diamond-bearing samples are relatively reduced (?FMQ-3.5 vs. -1.7 for barren eclogites). The Lahtojoki diamonds show evidence of formation from reduced mantle-derived carbon, based on the restricted range of ?13C values (-3 and -7.8 ‰; n = 67) that form a negativelyskewed distribution. This reduced CHO fluid was also anomalously N-rich, based on the diamond N contents that range up to 1830 at. ppm. While N-rich sources for eclogiteassociated diamonds are often linked to recycled crustal materials, in this case we prefer derivation from K-rich cratonic mantle metasomes due to lack of firm crustal geochemical signatures in the eclogites (?18O = 5.7 - 5.9 ‰), in addition to the magmatic history of the Karelian craton. The Karelian craton has been periodically intruded by Krich alkaline lamprophyres, Group-2 kimberlites and olivine lamproites from 1800 to 700 Ma. Such K-rich ultramafic alkaline magmatism is likely linked to phlogopite-rich metasomes, which may represent significant repositories of N (NH4+ substitution for K+). Because the Lahtojoki eclogites resided near the base of the lithospheric mantle, they would have been susceptible to interaction with ascending asthenosphere-derived C-bearing fluids/melts, which were reducing. Following ingress into and interaction with the Krich metasomatised Karelian mantle lithosphere, the increasingly N-enriched, CH4-bearing fluids precipitated diamond during interaction with relatively oxidized eclogite wall rock. In contrast to the prevalent oxidizing effects of mantle metasomatism as identified within cratonic lithosphere-derived samples from worldwide locations, the eclogite-hosted diamonds at Lahtojoki represent a natural example of metasomatic overprinting that was highly reducing.
DS201809-2099
2018
Tappe, S.Tappe, S., Dongre, A., Liu, C-Z., Wu, F-Y.Premier evidence for prolonged kimberlite pipe formation and its influence on diamond transport from deep Earth. Dikes sampled, geochronologyGeology, Vol. 46, pp. 843-846.Africa, South Africadeposit - Cullinan

Abstract: Volcanic pipes, or maar-diatreme volcanoes, form during explosive eruptions of mantle-derived magmas near Earth's surface. Impressive examples are the carrot-shaped, downward tapering structures formed by kimberlite magmas. Kimberlites originate from >150 km depth within Earth's mantle beneath thick continental roots, away from tectonic plate margins. Kimberlite pipes can be significant diamond deposits, and the complex architecture revealed during exploration and mining is ascribed to repeated magma injections leading to multiple eruptions. Repeated magmatic pulses cause diatremes to widen and grow downward, forming kilometer-sized subterranean structures. However, the time-resolved evolution of kimberlite pipe systems is largely unknown. We present the first U/Pb perovskite ages for newly discovered kimberlite dikes (1139.8 ± 4.8 Ma) that cut through the volcaniclastic infill of the Premier kimberlite pipe (1153.3 ± 5.3 Ma) at Cullinan Diamond Mine, South Africa. The ages reveal that renewed kimberlite volcanic activity occurred, at a minimum, 3 m.y. after the main pipe formation. This finding suggests that the largest kimberlite pipes, and maar-diatreme volcanoes in general, may be magmatically active for several millions of years, which conflicts with this volcanism being described as 'monogenetic' at millennia time scales. Exemplified by Tier-1 diamond deposits on the Kaapvaal craton, long-lasting kimberlite volcanic activity may be an important factor in growing large diatremes, plus enabling effective transport of mantle cargo from the diamond stability field to Earth's surface.
DS201811-2611
2018
Tappe, S.Sun, J., Tappe, S., Kostrovitsky, S.I., Liu, C-Z., Skuzovatov, S.Y., Wu, F-Y.Mantle sources of kimberlites through time: A U-Pb and Lu-Hf isotope study of zircon megacrysts from the Siberian diamond fields.Chemical Geology, Vol. 479, 1, pp. 228-240.Russia, Siberiageochronology

Abstract: A comprehensive, internally consistent U-Pb and Lu-Hf isotope data set for 93 mantle-derived zircons from the Yakutian kimberlite province confirms and further refines the four major episodes of kimberlite magmatism on the Siberian craton: 421-409?Ma (Late Silurian-Early Devonian), 358-353?Ma (Late Devonian-Early Carboniferous), 226-218?Ma (Late Triassic), and 161-144?Ma (Middle-Late Jurassic). The relatively narrow, constant range of eHf values between +2 and +10 for both the Paleozoic and Mesozoic mantle-derived zircons (and by inference kimberlites) suggests that the volatile-rich magmas were repeatedly sourced from the convecting upper mantle beneath the Siberian craton. This finding is in keeping with the narrow and constant range of eNd values for groundmass perovskites from the Yakutian kimberlite province between +1.8 and +5.5 between 420 and 150?Ma. Our preferred model implies that the convecting upper mantle beneath the Yakutian kimberlite province ‘recovered’ rapidly back to ambient conditions shortly after the giant plume-related flood volcanic event that produced the Siberian Traps at 250?Ma. Although close spatial relationships exist between kimberlites and flood basalts on the Siberian craton during both the Paleozoic and Mesozoic, exact timing of the igneous events and the isotopic compositions of the diverse deep-sourced melting products rule out any direct genetic links. Besides the highly economic kimberlite-hosted diamond deposits of Late Devonian age (e.g., Mir and Udachnaya), the Siberian craton also contains significant Mesozoic placer diamond deposits (e.g., along the Anabar river), for which lamproite sources have been suggested recently. Our study shows that mantle-derived zircon megacryst fragments from the Ebelyakh placer deposit have Late Triassic ages of ca. 224?Ma. Their long-term depleted Hf isotopic compositions (+8.5 eHf) suggest that the alluvial diamonds were sourced from asthenosphere-derived Triassic kimberlites rather than from lithospheric mantle derived isotopically enriched lamproites.
DS201812-2878
2018
Tappe, S.Shaikh, A.M., Patel, S.C., Bussweiler, Y., Kumar, S.P.K., Tappe, S., Mainkar, D. Ravi, S.Olivine trace element compositions in diamondiferous lamproites from India: proxies for magma origins and the nature of the lithosphere mantle beneath the Bastar and Dharwar cratons. CC2 and P13 Wajrakarur, Kodomali, Behradih Mainpur Lithos, doi:10.1016/j. lithos.2018.11.026 35p.Indiadeposit - Wajrakarur, Mainpur

Abstract: The ~1100 Ma CC2 and P13 lamproite dykes in the Wajrakarur Kimberlite Field (WKF), Eastern Dharwar Craton, and ~65 Ma Kodomali and Behradih lamproite diatremes in the Mainpur Kimberlite Field (MKF), Bastar Craton share a similar mineralogy, although the proportions of individual mineral phases vary significantly. The lamproites contain phenocrysts, macrocrysts and microcrysts of olivine set in a groundmass dominated by diopside and phlogopite with a subordinate amount of spinel, perovskite, apatite and serpentine along with rare barite. K-richterite occurs as inclusion in olivine phenocrysts in Kodomali, while it is a late groundmass phase in Behradih and CC2. Mineralogically, the studied intrusions are classified as olivine lamproites. Based on microtextures and compositions, three distinct populations of olivine are recognised. The first population comprises Mg-rich olivine macrocrysts (Fo89-93), which are interpreted to be xenocrysts derived from disaggregated mantle peridotites. The second population includes Fe-rich olivine macrocrysts (Fo82-89), which are suggested to be the product of metasomatism of mantle wall-rock by precursor lamproite melts. The third population comprises phenocrysts and overgrowth rims (Fo83-92), which are clearly of magmatic origin. The Mn and Al systematics of Mg-rich olivine xenocrysts indicate an origin from diverse mantle lithologies including garnet peridotite, garnet-spinel peridotite and spinel peridotite beneath the WKF, and mostly from garnet peridotite beneath the MKF. Modelling of temperatures calculated using the Al-in-olivine thermometer for olivine xenocrysts indicates a hotter palaeogeotherm of the SCLM beneath the WKF (between 41 and 43 mW/m2) at ~1100 Ma than beneath the MKF (between 38 and 41 mW/m2) at ~65 Ma. Further, a higher degree of metasomatism of the SCLM by precursor lamproite melts has occurred beneath the WKF compared to the MKF based on the extent of CaTi enrichment in Fe-rich olivine macrocrysts. For different lamproite intrusions within a given volcanic field, lower Fo olivine overgrowth rims are correlated with higher phlogopite plus oxide mineral abundances. A comparison of olivine overgrowth rims from the two fields shows that WKF olivines with lower Fo content than MKF olivines are associated with increased XMg in spinel and phlogopite and vice versa. Melt modelling indicates relatively Fe-rich parental melt for WKF intrusions compared to MKF intrusions. The Ni/Mg and Mn/Fe systematics of magmatic olivines indicate derivation of the lamproite melts from mantle source rocks with a higher proportion of phlogopite and/or lower proportion of orthopyroxene for the WKF on the Eastern Dharwar Craton compared to those for the MKF on the Bastar Craton. This study highlights how olivine cores provide important insights into the composition and thermal state of cratonic mantle lithosphere as sampled by lamproites, including clues to elusive precursor metasomatic events. Variable compositions of olivine rims testify to the complex interplay of parental magma composition and localised crystallisation conditions including oxygen fugacity variations, co-crystallisation of groundmass minerals, and assimilation of entrained material.
DS201901-0075
2018
Tappe, S.Shaikh, A.M., Patel, S.C., Bussweiler, Y., Kumar, S.P., Tappe, S., Ravi, S., Mainkar, D.Olivine trace element compositions in diamondiferous lamproites from India: proxies for magma origins and the nature of the lithospheric mantle beneath the Bastar and Dharwar cratons.Lithos, doi.org.10.1016/j.lithos.2018.11.026Indiadeposit - Wajrakarur, Mainpur

Abstract: The ~1100?Ma CC2 and P13 lamproite dykes in the Wajrakarur Kimberlite Field (WKF), Eastern Dharwar Craton, and ~65?Ma Kodomali and Behradih lamproite diatremes in the Mainpur Kimberlite Field (MKF), Bastar Craton share a similar mineralogy, although the proportions of individual mineral phases vary significantly. The lamproites contain phenocrysts, macrocrysts and microcrysts of olivine set in a groundmass dominated by diopside and phlogopite with a subordinate amount of spinel, perovskite, apatite and serpentine along with rare barite. K-richterite occurs as inclusion in olivine phenocrysts in Kodomali, while it is a late groundmass phase in Behradih and CC2. Mineralogically, the studied intrusions are classified as olivine lamproites. Based on microtextures and compositions, three distinct populations of olivine are recognised. The first population comprises Mg-rich olivine macrocrysts (Fo89-93), which are interpreted to be xenocrysts derived from disaggregated mantle peridotites. The second population includes Fe-rich olivine macrocrysts (Fo82-89), which are suggested to be the product of metasomatism of mantle wall-rock by precursor lamproite melts. The third population comprises phenocrysts and overgrowth rims (Fo83-92), which are clearly of magmatic origin. The Mn and Al systematics of Mg-rich olivine xenocrysts indicate an origin from diverse mantle lithologies including garnet peridotite, garnet-spinel peridotite and spinel peridotite beneath the WKF, and mostly from garnet peridotite beneath the MKF. Modelling of temperatures calculated using the Al-in-olivine thermometer for olivine xenocrysts indicates a hotter palaeogeotherm of the SCLM beneath the WKF (between 41 and 43?mW/m2) at ~1100?Ma than beneath the MKF (between 38 and 41?mW/m2) at ~65?Ma. Further, a higher degree of metasomatism of the SCLM by precursor lamproite melts has occurred beneath the WKF compared to the MKF based on the extent of CaTi enrichment in Fe-rich olivine macrocrysts. For different lamproite intrusions within a given volcanic field, lower Fo olivine overgrowth rims are correlated with higher phlogopite plus oxide mineral abundances. A comparison of olivine overgrowth rims from the two fields shows that WKF olivines with lower Fo content than MKF olivines are associated with increased XMg in spinel and phlogopite and vice versa. Melt modelling indicates relatively Fe-rich parental melt for WKF intrusions compared to MKF intrusions. The Ni/Mg and Mn/Fe systematics of magmatic olivines indicate derivation of the lamproite melts from mantle source rocks with a higher proportion of phlogopite and/or lower proportion of orthopyroxene for the WKF on the Eastern Dharwar Craton compared to those for the MKF on the Bastar Craton. This study highlights how olivine cores provide important insights into the composition and thermal state of cratonic mantle lithosphere as sampled by lamproites, including clues to elusive precursor metasomatic events. Variable compositions of olivine rims testify to the complex interplay of parental magma composition and localised crystallisation conditions including oxygen fugacity variations, co-crystallisation of groundmass minerals, and assimilation of entrained material.
DS201903-0497
2019
Tappe, S.Aulbach, S., Sun, J., Tappe, S., Gerdes, A.Effects of multi-stage rifting and metasomatism on HSE 187 Os 188 Os systematics of the cratonic mantle beneath SW Greenland. KimberlitesContributions to Mineralogy and Petrology, Vol. 174, 23p.Europe, Greenlandmetasomatism

Abstract: We report highly siderophile element (HSE) abundances and Re-Os isotope compositions, obtained by isotope dilution induc-tively coupled plasma mass spectrometry, of olivine separates from a suite of multiply metasomatised peridotite xenoliths entrained in kimberlites from SW Greenland. Combined with petrographic and compositional observations on accessory base metal sulphides (BMS), the results reveal new insights into the chemical, physical and mineralogical effects of multi-stage rifting and associated melt percolation on the Archaean lithospheric mantle. Refertilised lherzolites are dominated by rare to frequent small (tens of µm) BMS inclusions in olivine, whereas modally metasomatised phlogopite-bearing lherzolite and wehrlites have higher proportions of more Ni-rich BMS, including abundant large interstitial grains (hundreds of µm). The olivine separates display depleted HSE systematics with Primitive Upper Mantle (PUM)-normalised Pd/Ir of 0.014-0.62, and have both depleted and enriched 187 Os/ 188 Os (0.1139-0.2724) relative to chondrite that are not correlated with 187 Re/ 188 Os. Four out of ten olivine separates retain similarly depleted Os corresponding to Re-depletion model ages of 2.1-1.8 Ga. They may reflect Palaeoproterozoic refertilisation (lherzolitisation) during Laurentia plate assembly, with re-introduction of clinopyroxene and Os-rich BMS into the originally refractory mantle lithosphere by asthenosphere-derived basaltic melts, followed by recrystallisation and occlusion in olivine. Unradiogenic Os is observed regardless of lithology, including from peridotites that contain abundant interstitial BMS. This reflects addition of Os-poor BMS (<< 1 ppm) during more recent wehrlitisation and phlogopite-introduction, and control of the Os isotopic signature by older Os-rich BMS that precipitated from the basaltic melt. Depletions in compatible HSE (< 0.5 × PUM for Ru, Ir, Os) in all, but one olivine separate reflect nugget effects (amount of depleted vs. metasomatic BMS inclusions) and/or loss due to sulphide dissolution into oxidising small-volume melts that invaded the lithosphere during recurrent rifting, the latter supported by similar depletions in published bulk peridotite data. Combined, these multiple metasomatic events destroyed all vestiges of Mesoarchaean or older inheritance in the olivine separates investigated here, and highlight that caution is needed when interpreting Proterozoic Os model ages in terms of Proterozoic lithosphere stabilisation.
DS201904-0716
2019
Tappe, S.Aulbach, S., Tappe, S., Gerdes, A.Effects of multi-stage rifting and metasomatism on HSE-187Os/188Os systematic of the cratonic mantle beneath SW Greenland.Contributions to Mineralogy and Petrology, Vol. 174, 23p.Europe, Greenlandkimberlites

Abstract: We report highly siderophile element (HSE) abundances and Re-Os isotope compositions, obtained by isotope dilution inductively coupled plasma mass spectrometry, of olivine separates from a suite of multiply metasomatised peridotite xenoliths entrained in kimberlites from SW Greenland. Combined with petrographic and compositional observations on accessory base metal sulphides (BMS), the results reveal new insights into the chemical, physical and mineralogical effects of multi-stage rifting and associated melt percolation on the Archaean lithospheric mantle. Refertilised lherzolites are dominated by rare to frequent small (tens of µm) BMS inclusions in olivine, whereas modally metasomatised phlogopite-bearing lherzolite and wehrlites have higher proportions of more Ni-rich BMS, including abundant large interstitial grains (hundreds of µm). The olivine separates display depleted HSE systematics with Primitive Upper Mantle (PUM)-normalised Pd/Ir of 0.014-0.62, and have both depleted and enriched 187Os/188Os (0.1139-0.2724) relative to chondrite that are not correlated with 187Re/188Os. Four out of ten olivine separates retain similarly depleted Os corresponding to Re-depletion model ages of 2.1-1.8 Ga. They may reflect Palaeoproterozoic refertilisation (lherzolitisation) during Laurentia plate assembly, with re-introduction of clinopyroxene and Os-rich BMS into the originally refractory mantle lithosphere by asthenosphere-derived basaltic melts, followed by recrystallisation and occlusion in olivine. Unradiogenic Os is observed regardless of lithology, including from peridotites that contain abundant interstitial BMS. This reflects addition of Os-poor BMS (<
DS201906-1288
2019
Tappe, S.Dongre, A., Tappe, S.Kimberlite and carbonatite dykes within the Premier diatreme root ( Cullinan diamond mine, South Africa: new insights to mineralogical-genetic classifications and magma CO2 degassing.Lithos, Vol. 338-339, pp. 155-173.Africa, South Africadeposit - Cullinan

Abstract: The ca. 1153?Ma Premier kimberlite pipe on the Kaapvaal craton has been intruded by late-stage kimberlite and carbonatite magmas forming discrete 0.5 to 5?m wide dykes within the lower diatreme. On the basis of petrography and geochemistry, the fresh kimberlite dykes represent archetypal monticellite phlogopite kimberlite of Group-1 affinity. Their mineral compositions, however, show marked deviations from trends that are typically considered as diagnostic for Group-1 kimberlite in mineralogical-genetic classification schemes for volatile-rich ultramafic rocks. Groundmass spinel compositions are transitional between magnesian ulvöspinel (a Group-1 kimberlite hallmark feature) and titanomagnetite trends, the latter being more diagnostic for lamproite, orangeite (formerly Group-2 kimberlite), and aillikite. The Premier kimberlite dykes contain groundmass phlogopite that evolves by Al- and Ba-depletion to tetraferriphlogopite, a compositional trend that is more typical for orangeite and aillikite. Although high-pressure cognate and groundmass ilmenites from the Premier hypabyssal kimberlites are characteristically Mg-rich (up to 15?wt% MgO), they contain up to 5?wt% MnO, which is more typical for carbonate-rich magmatic systems such as aillikite and carbonatite. Manganese-rich groundmass ilmenite also occurs in the Premier carbonatite dykes, which are largely devoid of mantle-derived crystal cargo, suggesting a link to the kimberlite dykes by fractionation processes involving development of residual carbonate-rich melts and fluids. Although mineralogical-genetic classification schemes for kimberlites and related rocks may provide an elegant approach to circumvent common issues such as mantle debris entrainment, many of the key mineral compositional trends are not as robust for magma type identification as previously thought. Utilizing an experimentally constrained CO2-degassing model, it is suggested that the Premier kimberlite dykes have lost between 10 and 20?wt% CO2 during magma ascent through the cratonic lithosphere, prior to emplacement near the Earth's surface. Comparatively low fO2 values down to -5.6 ?NNO are obtained for the kimberlite dykes when applying monticellite and perovskite oxybarometry, which probably reflects significant CO2 degassing during magma ascent rather than the original magma redox conditions and those of the deep upper mantle source. Thus, groundmass mineral oxybarometry may have little value for the prediction of the diamond preservation potential of ascending kimberlite magmas. After correction for olivine fractionation and CO2-loss, there remains a wide gap between the primitive kimberlite and carbonatite melt compositions at Premier, which suggests that these magma types cannot be linked by variably low degrees of partial melting of the same carbonated peridotite source in the deep upper mantle. Instead, fractionation processes produced carbonate-rich residual melts/fluids from ascending kimberlite magma, which led to the carbonatite dykes within Premier pipe.
DS201909-2094
2019
Tappe, S.Tappe, S., Burness, S., Smart, K., Magna, T., Stracke, A.Views of plate tectonics and mantle metal budgets from alkaline and carbonate magmas.Goldschmidt2019, 1p. AbstractGlobalalkaline rocks

Abstract: Low-volume alkaline silicate and carbonate magmas are products of volatile-controlled incipient melting processes in the Earth’s mantle. Although this form of melting is ubiquitous beneath the thick and cold portions of continental lithosphere, such melts rarely reach the Earth’s surface due to a combination of their small volumes, reactive nature, and great depths of origin. In spite of being rare at surface, the impact of alkaline and carbonate magmatism on the dynamic stability of mantle lithosphere and its metal endowment may be disproportionately large, but it is difficult to grasp in the absence of spatial and temporal constraints on melt mobility. We review evidence from major alkaline and carbonatite provinces for metasomatic overprinting of the underlying continental mantle lithosphere, and evaluate how these processes influenced plate tectonic evolution in these regions. Key examples from Greenland and Africa show that metasomatic weakening of mantle lithosphere by pervasive alkaline and carbonate melts is frequently the first step in continent fragmentation ultimately leading to supercontinent dispersal. A major obstacle in identifying carbonate melt metasomatized mantle is the use of differentiated ‘surface’ carbonatite compositions as proxies for geochemical processes operating at great depths. We assess the robustness of some of the classic geochemical proxies, such as Ti/Eu and Zr/Sm, and identify new promising fingerprints of passing carbonate melts in the deep mantle lithosphere. New evidence from the Kaapvaal craton, one of world’s best endowed metallogenic provinces, shows that redox- and volatile-controlled alkaline melting events can effectively mobilize sulphide-hosted PGE and base metal budgets from eclogite components within the thick mantle lithosphere. Such precursor alkaline magmatic events, heralding the formation of major continental rifts and mantle plume impingement, can enhance the metal contents of subsequent asthenosphere-derived mafic magmas, thereby upgrading oreforming potential. However, economic metal deposits only form when geologic conditions during magma emplacement in the crust are favorable, with mantle metal budgets being less critical.
DS202003-0333
2020
Tappe, S.Burness, S., Smart, K.A., Tappe, S., Stevens, G., Woodland, A.B., Cano, E.Sulphur rich mantle metasomatism of Kaapvaal craton eclogites and its role in redox controlled platinum group element mobility. Xenoliths from Roberts Victor, Jagersfontein, Kimberley ( Kamfersdam), PremierChemical Geology, in press available 57p.Africa, South Africametasomatism

Abstract: Eclogite mantle xenoliths from various kimberlite occurrences on the Kaapvaal craton show evidence for depth- and redox-dependent metasomatic events that led to variable base metal sulphide and incompatible element enrichments. Eclogite xenoliths from the Roberts Victor, Jagersfontein, Kimberley (Kamfersdam) and Premier kimberlites were investigated for their silicate and base metal sulphide geochemistry, stable oxygen isotope compositions and oxybarometry. The variably metasomatised eclogites had basaltic, picritic and gabbroic protolith compositions and have garnet d18O values that range from +3.3 to +7.9‰, which, when coupled with the trace element characteristics, indicate oceanic lithosphere protoliths that had undergone variable degrees of seawater alteration. The deepest equilibrated eclogites (175220?km depth) from near the base of the Kaapvaal craton lithosphere are the most refractory and feature significant light rare earth element (LREE) depletions. They show the most oxidised redox compositions with ?logƒO2 values of FMQ-3.9 to FMQ-1.5. Subtle metasomatic overprinting of these eclogites resulted in base metal sulphide formation with relatively depleted and highly fractionated HSE compositions. These deepest eclogites and their included base metal sulphides suggest interaction with relatively oxidised melts or fluids, which, based on their HSE characteristics, could be related to precursor kimberlite metasomatism that was widespread within the Kaapvaal craton mantle lithosphere. In contrast, eclogites that reside at shallower, “mid-lithospheric” depths (140180?km) have been enriched in LREE and secondary diopside/phlogopite. Importantly, they host abundant metasomatic base metal sulphides, which have higher HSE contents than those in the deeper eclogites at the lithosphere base. The mid-lithospheric eclogites have more reducing redox compositions (?logfO2?=?FMQ-5.3 - FMQ-3.3) than the eclogites from the lowermost Kaapvaal lithosphere. The compositional overprint of the shallower mantle eclogites resembles basaltic rather than kimberlitic/carbonatitic metasomatism, which is also supported by their relatively reducing redox state. Base metal sulphides from the mid-lithospheric eclogites have HSE abundances and distributions that are similar to Karoo flood basalts from southern Africa, suggesting a link between the identified shallow mantle metasomatism of the Kaapvaal cratonic lithosphere and the Karoo large igneous event during the Mesozoic. The sulphide-hosted platinum group element abundances of the mid-lithospheric eclogites are higher compared with their analogues from the deeper lithospheric eclogites, which in combination with their contrasting oxidation states, may imply redox-controlled HSE mobility during sulphur-rich metasomatism of continental mantle lithosphere.
DS202007-1122
2020
Tappe, S.Amsellem, E., Moynier, F., Betrand, H., Bouyon, A., Mata, J., Tappe, S., Day, J.M.D.Calcium isotopic evidence for the mantle source of carbonatites.Science Adavances, Vol. 6, 63 eaba3269 6p. PdfMantlecarbonatite

Abstract: The origin of carbonatites—igneous rocks with more than 50% of carbonate minerals—and whether they originate from a primary mantle source or from recycling of surface materials are still debated. Calcium isotopes have the potential to resolve the origin of carbonatites, since marine carbonates are enriched in the lighter isotopes of Ca compared to the mantle. Here, we report the Ca isotopic compositions for 74 carbonatites and associated silicate rocks from continental and oceanic settings, spanning from 3 billion years ago to the present day, together with O and C isotopic ratios for 37 samples. Calcium-, Mg-, and Fe-rich carbonatites have isotopically lighter Ca than mantle-derived rocks such as basalts and fall within the range of isotopically light Ca from ancient marine carbonates. This signature reflects the composition of the source, which is isotopically light and is consistent with recycling of surface carbonate materials into the mantle.
DS202007-1174
2020
Tappe, S.Rooney, T., Girard, G., Tappe, S.The impact on mantle olivine resulting from carbonated silicate melt interaction. Allikite Superior cratonContributions to Mineralogy and Petrology, Vol. 175, 15p. Canadaolivine

Abstract: Interactions between carbonated ultramafic silicate magmas and the continental lithospheric mantle results in the formation of dunite—a ubiquitous xenolith type in kimberlites and aillikites. However, whether this process dominantly occurs in the mantle source region or by subsequent interactions between lithospheric mantle fragments and transporting silica-undersaturated magmas during ascent remains debated. Aillikite magmas, which are derived from the fusion of carbonate-phlogopite metasomes under diamond-stability field upper mantle conditions, have a mineralogically more complex source than kimberlites, providing an opportunity to more fully constrain the origin of dunite xenoliths in such deeply sourced carbonated silicate magmas. Here we present a major and trace element study of olivine occurring in xenoliths and as phenocrysts in an aillikite dike located on the southern Superior Craton. We show that olivine within the dunite microxenoliths exhibits extreme enrichment in Al, Cr, Na, and V when compared to equivalent xenoliths carried by kimberlites. We interpret these results as evidence for the presence of carbonate-phlogopite metasomes left residual in the cratonic mantle source during aillikite magma formation. Our results are inconsistent with models of dunite formation through orthopyroxene dissolution upon kimberlite/aillikite magma ascent, supporting an origin for such dunites that is more closely linked to primary melt generation at the base of relatively thick continental lithosphere. Our work demonstrates that it is possible to constrain the precursor composition of cratonic mantle dunite at depth, thereby facilitating the further exploration of how carbonated silicate magmas modify and weaken continental lithospheric roots.
DS202008-1372
2020
Tappe, S.Burness, S., Smart, K.A., Tappe, S., Stevens, G., Woodland, A.B., Cano, E.Sulphur rich mantle metasomatism of Kaapvaal craton eclogites and its role in redox controlled platinum group element mobility.Chemical Geology, Voll. 542, 119476 23p. pdfAfrica, South Africadeposit - Roberts Victor, Jagersfontein, Kimberley, Kamfersdam, Premier

Abstract: Eclogite mantle xenoliths from various kimberlite occurrences on the Kaapvaal craton show evidence for depth- and redox-dependent metasomatic events that led to variable base metal sulphide and incompatible element enrichments. Eclogite xenoliths from the Roberts Victor, Jagersfontein, Kimberley (Kamfersdam) and Premier kimberlites were investigated for their silicate and base metal sulphide geochemistry, stable oxygen isotope compositions and oxybarometry. The variably metasomatised eclogites had basaltic, picritic and gabbroic protolith compositions and have garnet d18O values that range from +3.3 to +7.9‰, which, when coupled with the trace element characteristics, indicate oceanic lithosphere protoliths that had undergone variable degrees of seawater alteration. The deepest equilibrated eclogites (175-220 km depth) from near the base of the Kaapvaal craton lithosphere are the most refractory and feature significant light rare earth element (LREE) depletions. They show the most oxidised redox compositions with ?logƒO2 values of FMQ-3.9 to FMQ-1.5. Subtle metasomatic overprinting of these eclogites resulted in base metal sulphide formation with relatively depleted and highly fractionated HSE compositions. These deepest eclogites and their included base metal sulphides suggest interaction with relatively oxidised melts or fluids, which, based on their HSE characteristics, could be related to precursor kimberlite metasomatism that was widespread within the Kaapvaal craton mantle lithosphere. In contrast, eclogites that reside at shallower, “mid-lithospheric” depths (140-180 km) have been enriched in LREE and secondary diopside/phlogopite. Importantly, they host abundant metasomatic base metal sulphides, which have higher HSE contents than those in the deeper eclogites at the lithosphere base. The mid-lithospheric eclogites have more reducing redox compositions (?logfO2 = FMQ-5.3 - FMQ-3.3) than the eclogites from the lowermost Kaapvaal lithosphere. The compositional overprint of the shallower mantle eclogites resembles basaltic rather than kimberlitic/carbonatitic metasomatism, which is also supported by their relatively reducing redox state. Base metal sulphides from the mid-lithospheric eclogites have HSE abundances and distributions that are similar to Karoo flood basalts from southern Africa, suggesting a link between the identified shallow mantle metasomatism of the Kaapvaal cratonic lithosphere and the Karoo large igneous event during the Mesozoic. The sulphide-hosted platinum group element abundances of the mid-lithospheric eclogites are higher compared with their analogues from the deeper lithospheric eclogites, which in combination with their contrasting oxidation states, may imply redox-controlled HSE mobility during sulphur-rich metasomatism of continental mantle lithosphere.
DS202009-1605
2020
Tappe, S.Amsellem, E., Moynier, F., Bertrand, H., Bouyon, A., Mata, J., Tappe, S., Day, J.M.D.Calcium isotopic evidence for the mantle sources of carbonatites. ( Oldoinyo Lengai)Science Advances, Vol. 6, eaba3269 June 3, 7p. PdfGlobal, Africa, Tanzaniacarbonatites

Abstract: The origin of carbonatites-igneous rocks with more than 50% of carbonate minerals-and whether they originate from a primary mantle source or from recycling of surface materials are still debated. Calcium isotopes have the potential to resolve the origin of carbonatites, since marine carbonates are enriched in the lighter isotopes of Ca compared to the mantle. Here, we report the Ca isotopic compositions for 74 carbonatites and associated silicate rocks from continental and oceanic settings, spanning from 3 billion years ago to the present day, together with O and C isotopic ratios for 37 samples. Calcium-, Mg-, and Fe-rich carbonatites have isotopically lighter Ca than mantle-derived rocks such as basalts and fall within the range of isotopically light Ca from ancient marine carbonates. This signature reflects the composition of the source, which is isotopically light and is consistent with recycling of surface carbonate materials into the mantle.
DS202009-1657
2020
Tappe, S.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.
DS202009-1668
2020
Tappe, S.Tappe, S., Budde, G., Stracke, A., Wilson, A., Kleine, T.The tungsten-182 record of kimberlites above the African superplume: exploring links to the core-mantle boundary. Ultradeep diamondsEarth and Planetary Science Letters, Vol. 547, 14p. PdfAfricaLLSVP, superplume

Abstract: Many volcanic hotspots are connected via ‘plume’ conduits to thermochemical structures with anomalously low seismic velocities at the core-mantle boundary. Basaltic lavas from some of these hotspots show anomalous daughter isotope abundances for the short-lived 129I-129Xe, 146Sm-142Nd, and 182Hf-182W radioactive decay systems, suggesting that their lower mantle sources contain material that dates back to Earth-forming events during the first 100 million years in solar system history. Survival of such ‘primordial’ remnants in Earth's mantle places important constraints on the evolution and inner workings of terrestrial planets. Here we report high-precision 182W/184W measurements for a large suite of kimberlite volcanic rocks from across the African tectonic plate, which for the past 250 million years has drifted over the most prominent thermochemical seismic anomaly at the core-mantle boundary. This so-called African LLSVP, or ‘large low shear-wave velocity province’, is widely suspected to store early Earth remnants and is implicated as the ultimate source of global Phanerozoic kimberlite magmatism. Our results show, however, that kimberlites from above the African LLSVP, including localities with lower mantle diamonds such as Letseng and Karowe Orapa A/K6, lack anomalous 182W signatures, with an average W value of 0.0 ± 4.1 (2SD) for the 18 occurrences studied. If kimberlites are indeed sourced from the African LLSVP or superplume, then the extensive 182W evidence suggests that primordial or core-equilibrated mantle materials, which may contribute resolvable W excesses or deficits, are only minor or locally concentrated components in the lowermost mantle, for example in the much smaller ‘ultra-low velocity zones’ or ULVZs. However, the lack of anomalous 182W may simply suggest that low-volume kimberlite magmas are not derived from hot lower mantle plumes. In this alternative scenario, kimberlite magmas originate from volatile-fluxed ambient convecting upper mantle domains beneath relatively thick and cold lithosphere from where previously ‘stranded’ lower mantle and transition zone diamonds can be plucked.
DS202009-1669
2020
Tappe, S.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 d13C 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; eNdi = +3.0 to +3.9 vs. +2.2 to +2.8; eHfi = -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 (?eHfi = -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 ?eHf 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.
DS202010-1853
2020
Tappe, S.Kumar, S.P., Shaikh, A.M., Patel, S.C., Sheikh, J.M., Behera, D., Pruseth, K.L., Ravi, S.,Tappe, S.Multi-stage magmatic evidence of olivine-leucite lamproite dykes from Banganapalle, Dharwar craton, India: evidence from compositional zoning of spinel.Mineralogy and Petrology, doi.org/10.1007/s00710-020-00722-y 26p. PdfIndialamproite

Abstract: Mesoproterozoic lamproite dykes occurring in the Banganapalle Lamproite Field of southern India show extensive hydrothermal alteration, but preserve fresh spinel, apatite and rutile in the groundmass. Spinels belong to three genetic populations. Spinels of the first population, which form crystal cores with overgrowth rims of later spinels, are Al-rich chromites derived from disaggregated mantle peridotite. Spinels of the second population include spongy-textured grains and alteration rims of titanian magnesian aluminous chromites that formed by metasomatic interactions between mantle wall-rocks and precursor lamproite melts before their entrainment into the erupting lamproite magma. Spinels that crystallised directly from the lamproite magma constitute the third population and show five distinct compositional subtypes (spinel-IIIa to IIIe), which represent discrete stages of crystal growth. First stage magmatic spinel (spinel-IIIa) includes continuously zoned macrocrysts of magnesian aluminous chromite, which formed together with Al-Cr-rich phlogopite macrocrysts from an earlier pulse of lamproite magma at mantle depth. Crystallisation of spinel during the other four identified stages occurred during magma emplacement at crustal levels. Titanian magnesian chromites (spinel-IIIb) form either discrete crystals or overgrowth rims on spinel-IIIa cores. Further generations of overgrowth rims comprise titanian magnesian aluminous chromite (spinel-IIIc), magnetite with ulvöspinel component (spinel-IIId) and lastly pure magnetite (spinel-IIIe). Abrupt changes of the compositions between successive zones of magmatic spinel indicate either a hiatus in the crystallisation history or co-crystallisation of other groundmass phases, or possibly magma mixing. This study highlights how different textural and compositional populations of spinel provide important insights into the complex evolution of lamproite magmas including clues to elusive precursor metasomatic events that affect cratonic mantle lithosphere.
DS202101-0025
2020
Tappe, S.Ngwenya, N.S., Tappe, S.Diamondiferous lamproites of the Luangwa Rift in central Africa and links to remobilized cratonic lithosphere.Chemical Geology, in press available 31p. PdfAfrica, Zambialamproite

Abstract: Mesozoic diamondiferous lamproite pipes occur along the Kapamba River within the Luangwa Valley of eastern Zambia, which is a ca. 300-200?Ma old Karoo-age precursor branch to the East African Rift System. The Luangwa Rift developed above a reactivated mega-shear zone that cuts through the Proterozoic Irumide Belt between the Congo-Tanzania-Kalahari cratons and thus it provides a rare snapshot of early-stage cratonic rift evolution. The primary mineralogy of the fresh volcanic rocks suggests that they represent a continuum between primitive olivine lamproites and slightly more evolved olivine-leucite lamproites. Mineral compositions and evolutionary trends, such as the strong Al-depletion at Tisingle bondF enrichment in groundmass phlogopite and potassic richterite, resemble those of classic lamproite provinces in circum-cratonic settings (e.g., the Leucite Hills of Wyoming and the West Kimberley field in Australia). However, there are some similarities to orangeites from the Kaapvaal craton (formerly Group-2 kimberlites), type kamafugites from the East African Rift, and ultramafic lamprophyres from a key region of the rifted North Atlantic craton, which implies a complex interplay between source-forming and tectonic processes during Karoo-age lamproite magma formation beneath south-central Africa. The bulk compositions of the Kapamba volcanic rocks fall within the range of ‘cratonic’ low-silica lamproites, but there is overlap with orangeites, in particular with the more evolved leucite- and sanidine-bearing orangeite varieties. Modelling of the process by which most of the original leucite was transformed into analcime suggests that the primitive alkaline magmas at Kapamba contained ~6-9?wt% K2O and had high K2O/Na2O ratios between ~1.6-6.2 at >10?wt% MgO - confirming the ultrapotassic nature of the mantle-derived magmatism beneath the Luangwa Rift. The virtually CO2-free, H2O-F-rich Kapamba lamproites present an extension of the geochemical continuum displayed by the members of the CO2-H2O-rich kamafugite / ultramafic lamprophyre group. Hence, we suggest that the Kapamba lamproites and the type kamafugites, located within separate branches of the East African Rift System, represent melting products of similar K-metasomatized cratonic mantle domains, but their formation occurred under contrasting volatile conditions at different stages during rift development (i.e., incipient versus slightly more advanced rifting). Temperature estimates for peridotite-derived olivine xenocrysts from the Kapamba lamproites suggest that the Luangwa Valley is an aborted cratonic rift that retained a relatively cold (=42?mW/m2) lithospheric mantle root down to ~180-200?km depth during the Mesozoic. Olivine major and trace element compositions support the presence of an Archean mantle root (up to 92.4?mol% forsterite contents) that is progressively metasomatized toward its base (e.g., increasing Tisingle bondCu contents with depth). For south-central Africa, it appears that significant volumes of Archean cratonic mantle domains ‘survived’ beneath strongly deformed and granite-intruded Proterozoic terranes, which suggests that the continental crust is more strongly impacted during collisional or rift tectonics than the ‘stabilizing’ mantle lithosphere.
DS201112-0281
2010
Tappeb, S.Donatti Filho, J.P., Paiva de Oliveira, E., Tappeb, S., Heaman, L.U Pb TIMS perovskite dating of the Brauna kimberlite field, Sao Francisco craton - Brazil: constraints on Neoproterozoic alkaline magmatism.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 81.South America, BrazilGeochronology
DS1991-0113
1991
Tapper, G.O.Beswick, A.E., Beckett, P.J., Courtin, G.M., Tapper, G.O.Evaluation of geobotanical remote sensing as an aid to mineral explorationin northeastern Ontario #2Ontario Geological Survey Open File, No. 5757, 22pOntarioGeobotany, Remote sensing
DS200912-0748
2009
Tappert, M.Tappert, R., Foden, J., Stachel, T., Muehlenbacher, K., Tappert, M., Wills, K.Deep mantle diamonds from South Australia: a record of Pacific subduction at the Gondwanan margin.Geology, Vol. 37, 1, pp. 43-46.Australia, South AustraliaDiamond genesis
DS200912-0749
2009
Tappert, M.Tappert, R., Foden, J., Stachel, T., Muehlenbachs, K., Tappert, M., Wills, K.The diamonds of South Australia.Lithos, In press available 49p.AustraliaDiamond inclusions
DS201212-0722
2012
Tappert, M.Tappert, R., Tappert, M.Diamonds in nature: a guide to rough diamonds.Crystallography Reviews, Vol. 18, 4, pp. 304-308.TechnologyDiamond morphology
DS201510-1809
2015
Tappert, M.Tappert, M.Advancements in hyderspectral drill core imaging of kimberlites: examples from Snap Lake and Tango Extension.Vancouver Kimberlite Cluster, Sept. 23, 1p. AbstractCanada, Northwest TerritoriesDeposit - Snap Lake, Tango Extension
DS201810-2384
2018
Tappert, M.Tappert, M.Novel exploration tools: using reflectance spectroscopy to detect hydration halos around kimberlites. Vancouver Kimberlite Cluster , Oct. 3, 1p. AbstractMantlespectroscopy

Abstract: Many kimberlite ore bodies are relatively small and the presence of overburden along with the complexities of interpreting geophysical data can make it challenging to intersect a kimberlite target during exploration drilling. However, the analysis of country rock drill core from the perimeter of several known kimberlites provides evidence that subtle alteration (hydration) halos around kimberlites exist, which can be detected using rapid and cost-effective spectroscopic techniques. Identification of these hydration halos, which are independent of country rock composition, may provide crucial information about the presence of undiscovered kimberlite in an exploration area, especially if kimberlite was not intersected during initial drilling. Preliminary estimates suggest that these hydration halos, which are most likely caused by kimberlite-derived hydrous fluids, can extend more than 65 meters into the country rocks, but their size strongly depends on the size of the kimberlite body. Narrow kimberlite dikes produce much smaller halos compared to large kimberlite pipes. In addition, hydration halos in carbonate rocks also appear to be smaller compared to silicate rocks.
DS201112-1032
2011
Tappert, M.C.Tappert, R., Tappert, M.C.The colors of diamonds.In: Diamonds in Nature, pp. 43-68.Definition - overview
DS201112-1033
2011
Tappert, M.C.Tappert, R., Tappert, M.C.The origin of diamond - diamond by definition is a mineral composed excleusively of the element carbon.In: Diamonds in Nature, pp. 1-14.Definition - overview
DS201112-1034
2011
Tappert, M.C.Tappert, R., Tappert, M.C.The morphology of diamonds.In: Diamonds in Nature, pp. 13-42.Diamond morphology
DS201112-1035
2011
Tappert, M.C.Tappert, R., Tappert, M.C.The surface textures of diamonds.In: Diamonds in Nature, pp. 69-90.Diamond textures
DS201412-0918
2014
Tappert, M.C.Tappert, M.C., Rivard, B., Layton-Matthews, D., Tappert, R.High-spatial resolution hyper spectral imagery: a new analytical technique for obtaining compositional information from kimberlites ( Snap Lake, NT) and kimberlite indicator minerals.2014 Yellowknife Geoscience Forum, p. 75, abstractCanada, Northwest TerritoriesDeposit - Snap Lake
DS201508-0377
2015
Tappert, M.C.Tappert, M.C., Rivard, B., Fulop, A., Rogge, D., Feng, J., Tappert, R., Stalder, R.Characterizing kimberlite dilution by crustal rocks at the Snap Lake diamond mine ( Northwest Territories, Canada) using SWIR ( 1.90-2.36 um) and LWIR ( 8.1-11.1um) hypersprectal imagery collected from drill core.Economic Geology, Vol. 110, 6, Sept-Oct. pp. 1375-1387.Canada, Northwest TerritoriesDeposit - Snap Lake
DS201512-1918
2015
Tappert, M.C.Feng, J., Tappert, M.C., Rivard, B.A., Fulop, A., Rogge, D., Tappert, R.Acquiring crustal dilution dat a and kimberlite compositional information from drill core using SWIR hyper spectral imagery from the Tango extension kimberlite.43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 39.Canada, Northwest TerritoriesDeposit - Tango

Abstract: Short-wave infrared (SWIR, 1.90-2.36 µm) hyperspectral imagery collected from 171 meters of drill core from the diamondiferous Tango Extension kimberlite using a high spatial resolution imaging system (pixel size: 1.43 x 1.43 µm) was analyzed to create compositional maps that show the distribution of different crustal (dilution) components and different kimberlite types along the drill core. Three types of crustal dilution components were identified in the compositional maps: carbonate, a carbonate-mudstone mixture, and mudstone. Five spectrally distinct types of kimberlite were identified, which differ mainly in their level of hydration and the amount of crustal micro-dilution they contain. Accompanying the compositional maps are depth profiles that provide quantitative abundance information for each compositional component (dilution and kimberlite). These profiles show the abundance of macro-dilution relative to kimberlite and the spatial distribution of the different kimberlite types. Using depth profiles, compositional boundaries along the length of the drill core were identified and compared to the unit boundaries from the visual lithological log. The boundaries identified using the hyperspectral imagery correlate well with the boundaries recorded during visual logging. This study demonstrates that hyperspectral imagery is well suited to the task of mapping the distribution of spectrally distinct kimberlite types, and quantifying kimberlite micro- and macro-dilution by crustal rocks.
DS201512-1977
2015
Tappert, M.C.Tappert, R., Tappert, M.C.hyper spectral imagery: a novel way to analyze kimberlite indicator minerals and to detect kimberlite micro-float.43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 102.Canada, Northwest TerritoriesHyperspectral imagery

Abstract: The collection and analysis of kimberlite indicator minerals from heavy mineral concentrates is an integral part of the diamond exploration process. However, surficial sampling programs are often restricted by time-consuming mineral collection, processing, and analysis procedures. To facilitate the development of a technique that can simplify and accelerate the identification and classification of kimberlite indicator minerals, we explored the usage of hyperspectral imagery, which is based on the analysis of reflected radiation in the visible and infrared parts of the electromagnetic spectrum. The investigation was focused on the identification of indicator garnets. Hyperspectral imagery was collected directly from heavy mineral concentrates, and these images were de-noised and processed to isolate the spectral absorption features relating to mineral composition. These images were then analyzed to identify individual garnets. This portion of the analysis was complemented by the results of 1000+ high-resolution spectra collected from well-characterized crust- and mantle-derived garnets to ensure that the garnets in the heavy mineral concentrates were accurately identified. Preliminary results indicate that garnets can be readily distinguished from other concentrate minerals using hyperspectral imagery, and that the garnets can also be compositionally classified. The compositional classification allows crust- and mantle-derived garnets to be distinguished accurately, while providing concentration information about certain transition elements, like chromium and titanium. In addition to the garnet analysis, hyperspectral imagery was also used to identify millimeter-sized fragments of kimberlite (kimberlite micro-float) in heavy mineral concentrates and unprocessed sediment samples. Preliminary results indicate that kimberlite micro-float can be readily distinguished from other rock and mineral fragments due to its distinct spectrum. Pending additional testing, analytical techniques using hyperspectral imagery may serve as an alternative to the costly and time-consuming indicator mineral identification methods currently being used.
DS201712-2732
2017
Tappert, M.C.Tappert, R., Tappert, M.C.Novel kimberlite exploration tools: delineating country rock hydration associated with kimberlites using Vis-SWIR hyper spectral point dat a collected from drill core.45th. Annual Yellowknife Geoscience Forum, p. 78 abstractCanada, Northwest Territories, Saskatchewandeposit - Kelvin, Faraday, Pikoo

Abstract: Many kimberlite ore bodies are relatively small and the presence of overburden can make it challenging to intersect a kimberlite target during exploration drilling. If kimberlite is not intersected during drilling, it can be difficult to decide whether an existing kimberlite body has been missed or whether the geophysical target was not kimberlite. A preliminary spectroscopic study conducted in 2017 provides evidence that kimberlites with sizes exceeding 30 meters hydrate the adjacent country rock. The detection of such ‘hydration halos’ in barren country rock drill cores can provide crucial evidence for the existence of nearby undiscovered kimberlites. To gain a better understanding about the size and morphology of hydration halos around different kimberlite ore bodies, hyperspectral point data were collected from drill cores comprised of crustal rocks recovered in close proximity to known kimberlites (e.g., Kelvin, Farraday, and Pikoo kimberlites). The information obtained as a result of this study will likely serve as a foundation for the development of a rapid, low-cost kimberlite exploration tool that can help evaluate kimberlite potential in areas where kimberlite was not intersected during drilling.
DS201904-0787
2019
Tappert, M.C.Tappert, R., Foden, J., Heaman, L., Tappert, M.C., Zurevinski, S.E., Wills, K.The petrology of kimberlites from South Australia: linking olivine macrocrystic and micaceous kimberlites.Journal of Volacnology and Geothermal Research, Vol. 373, pp. 68-96.Australia, South Australiadeposit - Eurelia

Abstract: Kimberlites of Jurassic age occur in various parts of South Australia. Thirty-nine of these kimberlites, which are mostly new discoveries, were studied to characterize their structural setting, their petrography, and the composition of their constituent minerals. Although some of the kimberlites in South Australia occur on the Archean to Paleoproterozoic Gawler Block, most are part of a northwest-trending, semi-continuous kimberlite dike swarm located in the Adelaide Fold Belt. The kimberlites typically occur as dikes or sills, but diatremes are also present. In the Adelaide Fold Belt, diatremes are restricted to the hinge zones of regional-scale folds within thick sedimentary sequences of the Adelaidean Supergroup. Despite widespread and severe alteration, coherent and pyroclastic kimberlites can be readily distinguished. U-Pb and Sr/Nd isotopic compositions of groundmass perovskite indicate that all kimberlites belong to the same age group (177-197?Ma) and formed in a near-primitive mantle environment (87Sr/86Sr: 0.7038-0.7052, eNd: -0.07 to +2.97). However, the kimberlites in South Australia are compositionally diverse, and range from olivine-dominated varieties (macrocrystic kimberlites) to olivine-poor, phlogopite-dominated varieties (micaceous kimberlites). Macrocrystic kimberlites contain magnesium-rich groundmass phlogopite and spinel, and they are typically olivine macrocryst-rich. Micaceous kimberlites, in contrast, contain more iron- and titanium-rich groundmass phlogopite and less magnesian spinel, and olivine macrocrysts are rare or absent. Correlations between phlogopite and spinel compositions with modal abundances of olivine, indicate that the contrast between macrocrystic and micaceous kimberlites is primarily linked to the amount of mantle components that were incorporated into a compositionally uniform parental mafic silicate melt. We propose that assimilation of xenocrystic magnesite and incorporation of xenocrystic olivine from dunitic source rocks were the key processes that modified the parental silicate melt and created the unique hybrid (carbonate-silicate) character of kimberlites. Based on the composition of xenoliths and xenocrysts, the lithospheric mantle sampled by the South Australian kimberlites is relatively uniform, and extends to depths of 160-170?km, which is slightly below the diamond stability field. Only beneath the Eurelia area does the lithosphere appear thicker (>175?km), which is consistent with the presence of diamonds in some of the Eurelia kimberlites.
DS2001-1121
2001
Tappert, R.Stachel, T., Harris, J.W., Tappert, R.Inclusions in diamonds from the PAnd a kimberlite29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p. 80.Northwest TerritoriesDiamond - inclusions, Deposit - Panda
DS2001-1122
2001
Tappert, R.Stachel, T., Harris, J.W., Tappert, R., Brey, G.P.Peridotitic inclusions in diamonds from the Slave and Kaapvaal cratons - afirst comparison.Slave-Kaapvaal Workshop, Sept. Ottawa, 4p. abstractNorthwest Territories, South AfricaDiamond - inclusions, Geochemistry - major and trace elements Panda
DS2002-1538
2002
Tappert, R.Stachel, T., Tappert, R., Harris, J.W.PAnd a diamonds: a window into the deep lithosphere beneath the central SlaveGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.112., p.112.Northwest TerritoriesGeochronology, Diamond - inclusions
DS2002-1539
2002
Tappert, R.Stachel, T., Tappert, R., Harris, J.W.PAnd a diamonds: a window into the deep lithosphere beneath the central SlaveGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.112., p.112.Northwest TerritoriesGeochronology, Diamond - inclusions
DS2002-1579
2002
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Brey, G.P.Composition of mineral inclusions from Brazilian diamondsGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.116., p.116.BrazilAlluvials, Deposit - Aranapolis, Canastra
DS2002-1580
2002
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Brey, G.P.Composition of mineral inclusions from Brazilian diamondsGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.116., p.116.BrazilAlluvials, Deposit - Aranapolis, Canastra
DS2003-1324
2003
Tappert, R.Stachel, 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
DS2003-1325
2003
Tappert, R.Stachel, T., Harris, J.W., Tappert, R., Brey, G.P.Peridotitic diamonds from the Slave and the Kaapvaal cratons similarities andLithos, Vol. 71, 2-4, pp. 489-503.South Africa, Northwest Territories, NunavutMineral chemistry
DS2003-1359
2003
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Brey, G.P.Mineral inclusions in diamonds from the PAnd a kimberlite, Slave Province, Canada8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractNorthwest TerritoriesDiamonds - inclusions, Deposit - Panda
DS200412-1905
2004
Tappert, R.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
DS200412-1906
2003
Tappert, R.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
DS200412-1910
2003
Tappert, R.Stachel, T., Harris, J.W., Tappert, R., Brey, G.P.Peridotitic diamonds from the Slave and the Kaapvaal cratons similarities and differences based on a preliminary dat a set.Lithos, Vol. 71, 2-4, pp. 489-503.Africa, South Africa, Northwest Territories, NunavutMineral chemistry
DS200412-1964
2004
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Brey, G.P., Ludwig, T.Messingers from the sublithospheric mantle: diamonds and their mineral inclusions from the Jagersfontein kimberlite ( South AfriGeological Association of Canada Abstract Volume, May 12-14, SS14-11 p. 270.abstractAfrica, South AfricaDiamond inclusions, morphology
DS200512-1073
2005
Tappert, R.Tappert, R., Stachel, R.Subducting oceanic crust: the source of deep diamonds.Geology, Vol. 33, 7, July, pp. 565-568.Africa, South AfricaJagersfontein, majorite, diamond inclusions, Eu anomalies
DS200512-1074
2005
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Shimizu, N., Brey, G.P.Mineral inclusions in diamonds from the PAnd a kimberlite, Slave Province, Canada.European Journal of Mineralogy, Vol. 17, 3, pp. 423-440.Canada, Northwest TerritoriesMineralogy - Panda
DS200612-1412
2006
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Muehlenbachs, K., Brey, G.P.Placer diamonds from Brazil: indicators of the composition of the Earth's mantle and the distance to their kimberlitic sources.Economic Geology, Vol. 101, 2, pp. 543-470.South America, Brazil, Mato Grosso, Roraima, Minas GeraisDiamond morphology, inclusions
DS200612-1413
2005
Tappert, R.Tappert, R., Stachel, T., Harris, J.W., Muehlenbachs, K., Ludwig, T., Brey, G.P.Diamonds from Jagersfontein (South Africa): messengers from the sublithopheric mantle.Contributions to Mineralogy and Petrology, Vol. 150, 5, pp. 505-522.Africa, South AfricaDiamond inclusions
DS200612-1414
2006
Tappert, R.Tappert, R., Stachel, T., Muehlenbachs, K., Harris, J.W., Brey, G.P.Alluvial diamonds from Brazil: where and what are their sources?Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 4. abstract onlySouth America, BrazilDiamond genesis
DS200812-0360
2008
Tappert, R.Foden, J., Tappert, R., Wills, K.The source and origin of the Mesozoic kimberlites in South Australia.9IKC.com, 3p. extended abstractAustraliaDeposit - Eurelia
DS200912-0748
2009
Tappert, R.Tappert, R., Foden, J., Stachel, T., Muehlenbacher, K., Tappert, M., Wills, K.Deep mantle diamonds from South Australia: a record of Pacific subduction at the Gondwanan margin.Geology, Vol. 37, 1, pp. 43-46.Australia, South AustraliaDiamond genesis
DS200912-0749
2009
Tappert, R.Tappert, R., Foden, J., Stachel, T., Muehlenbachs, K., Tappert, M., Wills, K.The diamonds of South Australia.Lithos, In press available 49p.AustraliaDiamond inclusions
DS200912-0750
2009
Tappert, R.Tappert, R., Foden, J., Wills, K.The petrology of kimberlites in South Australia.Goldschmidt Conference 2009, p. A1315 Abstract.AustraliaDeposit - Eurelia
DS201112-1030
2005
Tappert, R.Tappert, R.The nature of diamonds and their mineral inclusions: a study of diamonds from the PAnd a and Jagersfontein kimberlites and from placer deposits in Brazil.Thesis, University of Alberta, Earth and Atmospheric Sciences, 214p.Canada, Northwest Territories, Africa, South Africa, BrazilThesis - note availability based on request to author
DS201112-1031
2011
Tappert, R.Tappert, R., Foden, J., Muehlenbachs, K., Wills, K.Garnet peridotite xenoliths and xenocrysts from the Monk Hill kimberlite, South Australia: insights into the lithospheric mantle beneath the Adelaide fold belt.Journal of Petrology, Vol. 52, no. 10, pp. 1965-1986.AustraliaDeposit - Monk Hill
DS201112-1032
2011
Tappert, R.Tappert, R., Tappert, M.C.The colors of diamonds.In: Diamonds in Nature, pp. 43-68.Definition - overview
DS201112-1033
2011
Tappert, R.Tappert, R., Tappert, M.C.The origin of diamond - diamond by definition is a mineral composed excleusively of the element carbon.In: Diamonds in Nature, pp. 1-14.Definition - overview
DS201112-1034
2011
Tappert, R.Tappert, R., Tappert, M.C.The morphology of diamonds.In: Diamonds in Nature, pp. 13-42.Diamond morphology
DS201112-1035
2011
Tappert, R.Tappert, R., Tappert, M.C.The surface textures of diamonds.In: Diamonds in Nature, pp. 69-90.Diamond textures
DS201212-0722
2012
Tappert, R.Tappert, R., Tappert, M.Diamonds in nature: a guide to rough diamonds.Crystallography Reviews, Vol. 18, 4, pp. 304-308.TechnologyDiamond morphology
DS201412-0918
2014
Tappert, R.Tappert, M.C., Rivard, B., Layton-Matthews, D., Tappert, R.High-spatial resolution hyper spectral imagery: a new analytical technique for obtaining compositional information from kimberlites ( Snap Lake, NT) and kimberlite indicator minerals.2014 Yellowknife Geoscience Forum, p. 75, abstractCanada, Northwest TerritoriesDeposit - Snap Lake
DS201508-0377
2015
Tappert, R.Tappert, M.C., Rivard, B., Fulop, A., Rogge, D., Feng, J., Tappert, R., Stalder, R.Characterizing kimberlite dilution by crustal rocks at the Snap Lake diamond mine ( Northwest Territories, Canada) using SWIR ( 1.90-2.36 um) and LWIR ( 8.1-11.1um) hypersprectal imagery collected from drill core.Economic Geology, Vol. 110, 6, Sept-Oct. pp. 1375-1387.Canada, Northwest TerritoriesDeposit - Snap Lake
DS201512-1918
2015
Tappert, R.Feng, J., Tappert, M.C., Rivard, B.A., Fulop, A., Rogge, D., Tappert, R.Acquiring crustal dilution dat a and kimberlite compositional information from drill core using SWIR hyper spectral imagery from the Tango extension kimberlite.43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 39.Canada, Northwest TerritoriesDeposit - Tango

Abstract: Short-wave infrared (SWIR, 1.90-2.36 µm) hyperspectral imagery collected from 171 meters of drill core from the diamondiferous Tango Extension kimberlite using a high spatial resolution imaging system (pixel size: 1.43 x 1.43 µm) was analyzed to create compositional maps that show the distribution of different crustal (dilution) components and different kimberlite types along the drill core. Three types of crustal dilution components were identified in the compositional maps: carbonate, a carbonate-mudstone mixture, and mudstone. Five spectrally distinct types of kimberlite were identified, which differ mainly in their level of hydration and the amount of crustal micro-dilution they contain. Accompanying the compositional maps are depth profiles that provide quantitative abundance information for each compositional component (dilution and kimberlite). These profiles show the abundance of macro-dilution relative to kimberlite and the spatial distribution of the different kimberlite types. Using depth profiles, compositional boundaries along the length of the drill core were identified and compared to the unit boundaries from the visual lithological log. The boundaries identified using the hyperspectral imagery correlate well with the boundaries recorded during visual logging. This study demonstrates that hyperspectral imagery is well suited to the task of mapping the distribution of spectrally distinct kimberlite types, and quantifying kimberlite micro- and macro-dilution by crustal rocks.
DS201512-1977
2015
Tappert, R.Tappert, R., Tappert, M.C.hyper spectral imagery: a novel way to analyze kimberlite indicator minerals and to detect kimberlite micro-float.43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 102.Canada, Northwest TerritoriesHyperspectral imagery

Abstract: The collection and analysis of kimberlite indicator minerals from heavy mineral concentrates is an integral part of the diamond exploration process. However, surficial sampling programs are often restricted by time-consuming mineral collection, processing, and analysis procedures. To facilitate the development of a technique that can simplify and accelerate the identification and classification of kimberlite indicator minerals, we explored the usage of hyperspectral imagery, which is based on the analysis of reflected radiation in the visible and infrared parts of the electromagnetic spectrum. The investigation was focused on the identification of indicator garnets. Hyperspectral imagery was collected directly from heavy mineral concentrates, and these images were de-noised and processed to isolate the spectral absorption features relating to mineral composition. These images were then analyzed to identify individual garnets. This portion of the analysis was complemented by the results of 1000+ high-resolution spectra collected from well-characterized crust- and mantle-derived garnets to ensure that the garnets in the heavy mineral concentrates were accurately identified. Preliminary results indicate that garnets can be readily distinguished from other concentrate minerals using hyperspectral imagery, and that the garnets can also be compositionally classified. The compositional classification allows crust- and mantle-derived garnets to be distinguished accurately, while providing concentration information about certain transition elements, like chromium and titanium. In addition to the garnet analysis, hyperspectral imagery was also used to identify millimeter-sized fragments of kimberlite (kimberlite micro-float) in heavy mineral concentrates and unprocessed sediment samples. Preliminary results indicate that kimberlite micro-float can be readily distinguished from other rock and mineral fragments due to its distinct spectrum. Pending additional testing, analytical techniques using hyperspectral imagery may serve as an alternative to the costly and time-consuming indicator mineral identification methods currently being used.
DS201712-2732
2017
Tappert, R.Tappert, R., Tappert, M.C.Novel kimberlite exploration tools: delineating country rock hydration associated with kimberlites using Vis-SWIR hyper spectral point dat a collected from drill core.45th. Annual Yellowknife Geoscience Forum, p. 78 abstractCanada, Northwest Territories, Saskatchewandeposit - Kelvin, Faraday, Pikoo

Abstract: Many kimberlite ore bodies are relatively small and the presence of overburden can make it challenging to intersect a kimberlite target during exploration drilling. If kimberlite is not intersected during drilling, it can be difficult to decide whether an existing kimberlite body has been missed or whether the geophysical target was not kimberlite. A preliminary spectroscopic study conducted in 2017 provides evidence that kimberlites with sizes exceeding 30 meters hydrate the adjacent country rock. The detection of such ‘hydration halos’ in barren country rock drill cores can provide crucial evidence for the existence of nearby undiscovered kimberlites. To gain a better understanding about the size and morphology of hydration halos around different kimberlite ore bodies, hyperspectral point data were collected from drill cores comprised of crustal rocks recovered in close proximity to known kimberlites (e.g., Kelvin, Farraday, and Pikoo kimberlites). The information obtained as a result of this study will likely serve as a foundation for the development of a rapid, low-cost kimberlite exploration tool that can help evaluate kimberlite potential in areas where kimberlite was not intersected during drilling.
DS201904-0787
2019
Tappert, R.Tappert, R., Foden, J., Heaman, L., Tappert, M.C., Zurevinski, S.E., Wills, K.The petrology of kimberlites from South Australia: linking olivine macrocrystic and micaceous kimberlites.Journal of Volacnology and Geothermal Research, Vol. 373, pp. 68-96.Australia, South Australiadeposit - Eurelia

Abstract: Kimberlites of Jurassic age occur in various parts of South Australia. Thirty-nine of these kimberlites, which are mostly new discoveries, were studied to characterize their structural setting, their petrography, and the composition of their constituent minerals. Although some of the kimberlites in South Australia occur on the Archean to Paleoproterozoic Gawler Block, most are part of a northwest-trending, semi-continuous kimberlite dike swarm located in the Adelaide Fold Belt. The kimberlites typically occur as dikes or sills, but diatremes are also present. In the Adelaide Fold Belt, diatremes are restricted to the hinge zones of regional-scale folds within thick sedimentary sequences of the Adelaidean Supergroup. Despite widespread and severe alteration, coherent and pyroclastic kimberlites can be readily distinguished. U-Pb and Sr/Nd isotopic compositions of groundmass perovskite indicate that all kimberlites belong to the same age group (177-197?Ma) and formed in a near-primitive mantle environment (87Sr/86Sr: 0.7038-0.7052, eNd: -0.07 to +2.97). However, the kimberlites in South Australia are compositionally diverse, and range from olivine-dominated varieties (macrocrystic kimberlites) to olivine-poor, phlogopite-dominated varieties (micaceous kimberlites). Macrocrystic kimberlites contain magnesium-rich groundmass phlogopite and spinel, and they are typically olivine macrocryst-rich. Micaceous kimberlites, in contrast, contain more iron- and titanium-rich groundmass phlogopite and less magnesian spinel, and olivine macrocrysts are rare or absent. Correlations between phlogopite and spinel compositions with modal abundances of olivine, indicate that the contrast between macrocrystic and micaceous kimberlites is primarily linked to the amount of mantle components that were incorporated into a compositionally uniform parental mafic silicate melt. We propose that assimilation of xenocrystic magnesite and incorporation of xenocrystic olivine from dunitic source rocks were the key processes that modified the parental silicate melt and created the unique hybrid (carbonate-silicate) character of kimberlites. Based on the composition of xenoliths and xenocrysts, the lithospheric mantle sampled by the South Australian kimberlites is relatively uniform, and extends to depths of 160-170?km, which is slightly below the diamond stability field. Only beneath the Eurelia area does the lithosphere appear thicker (>175?km), which is consistent with the presence of diamonds in some of the Eurelia kimberlites.
DS2003-1156
2003
Tapponier, P.Replumaz, A., Tapponier, P.Reconstruction of the deformed collision zone between India and Asia by backwardJournal of Geophysical Research, Vol. 108, B6, 10.1029/2002JB000661 June 3India, AsiaTectonics
DS200412-1655
2003
Tapponier, P.Replumaz, A., Tapponier, P.Reconstruction of the deformed collision zone between India and Asia by backward motion of lithospheric blocks.Journal of Geophysical Research, Vol. 108, B6, 10.1029/2002 JB000661 June 3India, AsiaTectonics
DS1999-0154
1999
TapponnierCourtillot, V., Jaupart, C., Manighetti, TapponnierOn causal links between flood basalts and continental breakupEarth and Planetary Science Letters, Vol. 166, No. 3-4, Mar. pp. 177-196.GlobalBasalts, Tectonics
DS200412-1654
2004
Tapponnier, P.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
DS1988-0685
1988
Tapraeva, A.Tapraeva, A., Pushkin, A.N., Kulakova, I.I., Rudenko, A.P.Kinetics of oxidation of kimberlite diamonds as modified by methane andhydrogen.(Russian)V. Mosk. U. Kh., (russian), Vol, 29, No. 2, March-April pp. 211-215RussiaBlank
DS201810-2360
2018
Tapster, S.R.Nasdala, 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°6Pb/²³8U 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 × 10¹8 g?¹ (GZ7) and 2.53 × 10¹8 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 µg g?¹ (GZ7) and 1305 µg 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 µg g?¹ ± 0.18 µg g?¹; 95% confidence uncertainty) may prove useful as reference material for Ti-in-zircon temperature estimates.
DS1999-0727
1999
Tarabukin, V.Tarabukin, V., Kanygin, Smironov, Pavlushin, BuyankinaFindings of Paleozoic conodonts in xenoliths from kimberlite pipes on the Siberian PlatformRussian Geology and Geophysics, Vol. 40, No. 6, pp. 818-26.Russia, SiberiaXenoliths
DS200812-0338
2008
Taraevich, A.V.Fang, L., Kononov, O.V., Marfunin, A.S., Taraevich, A.V., Tarasavich, B.N.Development of a technique for IR spectroscopic determination of nitrogen content and aggregation degree in diamond crystals.Moscow University Geology Bulletin, Vol. 63, 4, pp. 281-284.TechnologyDiamond morphology
DS201504-0224
2015
Tarakanov, R.Z.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
DS2001-0118
2001
Taran, L.Bogdanova, S.V., Page, L.M., Skridlaite, G., Taran, L.Proterozoic tectonothermal history in the western part of the East European Craton: 40 Ar 39 Ar constraints..#2Tectonophysics, Vol. 339, No. 1-2, pp. 39-66.EuropeGeochronology, Craton
DS2001-0119
2001
Taran, L.N.Bogdanova, S.V., Page, L.M., Skridlaite, G., Taran, L.N.Proterozoic tectonothermal history in the western part of the East European Craton: 40 Ar 39 Ar constraints #1Tectonophysics, Vol. 339, No. 1-2, pp. 183-92.EuropePaleomagnetics, Tectonics
DS2002-0896
2002
taran, L.N.Kozlovskaya, E., taran, L.N., Yliniemi, J., Giese, R., Karatayev, G.I.Deep structure of the crust along the Fennoscandia Sarmatia Junction Zone ( CentralTectonophysics, Vol. 358,1-4,pp. 97-120.Fennoscandia, Europe, UralsTectonics
DS202003-0338
2020
Taran, M.Franz, G., Vyshnevsky, O., Taran, M., Khomenko, V., Wiedenbeck, M., Schiperski, F., Nissen, J.A new emerald occurrence from Kruta Balka, western Peri-Azovian, Ukraine: implications for understanding the crystal chemistry of emerald.American Mineralogist, Vol. 105, pp. 162-181. pdfEurope, Ukraineemerald

Abstract: We investigated emerald, the bright-green gem variety of beryl, from a new locality at Kruta Balka, Ukraine, and compare its chemical characteristics with those of emeralds from selected occurrences worldwide (Austria, Australia, Colombia, South Africa, Russia) to clarify the types and amounts of substitutions as well as the factors controlling such substitutions. For selected crystals, Be and Li were determined by secondary ion mass spectrometry, which showed that the generally assumed value of 3 Be atoms per formula unit (apfu) is valid; only some samples such as the emerald from Kruta Balka deviate from this value (2.944 Be apfu). An important substitution in emerald (expressed as an exchange vector with the additive component Al2Be3Si6O18) is (Mg,Fe2+)NaAl1?1, leading to a hypothetical end-member NaAl(Mg,Fe2+)[Be3Si6O18] called femag-beryl with Na occupying a vacancy position (?) in the structural channels of beryl. Based on both our results and data from the literature, emeralds worldwide can be characterized based on the amount of femag-substitution. Other minor substitutions in Li-bearing emerald include the exchange vectors LiNa2Al1?2 and LiNaBe1?1, where the former is unique to the Kruta Balka emeralds. Rarely, some Li can also be situated at a channel site, based on stoichiometric considerations. Both Cr- and V-distribution can be very heterogeneous in individual crystals, as shown in the samples from Kruta Balka, Madagascar, and Zimbabwe. Nevertheless, taking average values available for emerald occurrences, the Cr/(Cr+V) ratio (Cr#) in combination with the Mg/(Mg+Fe) ratio (Mg#) and the amount of femag-substitution allows emerald occurrences to be characterized. The "ultramafic" schist-type emeralds with high Cr# and Mg# come from occur-rences where the Fe-Mg-Cr-V component is controlled by the presence of ultramafic meta-igneous rocks. Emeralds with highly variable Mg# come from "sedimentary" localities, where the Fe-Mg-Cr-V component is controlled by metamorphosed sediments such as black shales and carbonates. A "transitional" group has both metasediments and ultramafic rocks as country rocks. Most "ultramafic" schist type occurrences are characterized by a high amount of femag-component, whereas those from the "sedimentary" and "transitional" groups have low femag contents. Growth conditions derived from the zoning pattern combined replacement, sector, and oscillatory zoning in the Kruta Balka emeralds indicate disequilibrium growth from a fluid along with late-stage Na-infiltration. Inclusions in Kruta Balka emeralds (zircon with up to 11 wt% Hf, tourmaline, albite, Sc-bearing apatite) point to a pegmatitic origin.
DS1988-0393
1988
Taran, M.N.Kvasnitsa, V.N., Taran, M.N., Smirnov, G.I., Legkova, G.V.Violet red zircon from kimberlite.(Russian)Mineral. Zhurnal, (Russian), Vol. 42, No. 2, pp. 12-17LesothoDiamond morphology, Zircon
DS1988-0445
1988
Taran, M.N.Matsyuk, S.S., Platonov, A.N., Taran, M.N., Nazarov, Yu.N., Dunaeva, G.V.Optical spectroscopy as an effective investigative method when prospecting for kimberlites.*UKR.Visn. Akad. Nauk UKR. RSR, *UKR., No. 2, pp. 53-59RussiaBlank
DS1989-0753
1989
Taran, M.N.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
DS1990-1445
1990
Taran, M.N.Taran, M.N., Bagmut, N.N., Kvasnitsa, V.N., Kharkiv, A.D.Optical and EPR-spectra of natural kimberlite-type zircons.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 2, pp. 44-51RussiaKimberlites, Spectroscopy
DS1991-1356
1991
Taran, M.N.Platonov, A.N., Langer, K., Matsuk, S.S., Taran, M.N., Hu, X.iron 2 Ti4 Charge transfer in garnets from mantle eclogitesEuropean Journal of Mineralogy, Vol. 3, No. 1, pp. 19-26GlobalMineralogy, Eclogites -garnet
DS200412-1965
2004
Taran, M.N.Taran, M.N., Kvasnytsya, V.M., Langer, K.On unusual deep violet microcrystals of diamonds from placers of Ukraine.European Journal of Mineralogy, Vol. 16, 2,pp. 241-245.Europe, UkraineDiamond morphology
DS200612-1415
2006
Taran, M.N.Taran, M.N., Kvasnytsya, V.M., Langer, K., Ilchenko, K.O.Infrared spectroscopy study of nitrogen centers in microdiamonds from Ukrainian Neogene placers.European Journal of Mineralogy, Vol. 18, 1, pp. 71-81.Europe, Ukraine, RussiaMicrodiamonds
DS201412-0919
2014
Taran, M.N.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
DS1983-0593
1983
Taranenko, V.I.Taranenko, V.I., Prokopchuk, B.I., Yanygin, YU.T., Shapovalova.Paleogeomorphological Environment of Diamond Placer Genesis at the Southeastern Slope of the Tunguska Syneclise During The Late Paleozoic.Geomorfologiya., 1983 (2), PP. 48-53.RussiaGeomorphology, Alluvial Placers
DS1993-1062
1993
Taranenko, V.I.Mityukhin, S.I., Taranenko, V.I.Diamond prospecting by correlation of stratigraphy andgeological/historical interpretation.Diamonds of Yakutia, pp. 67-70.Russia, YakutiaProspecting, Stratigraphy
DS1994-0410
1994
Taranik, J.V.De Miranda, F.P., MCCafferty, A.E., Taranik, J.V.Reconnaissance geologic mapping of portion of rain forest covered Guianashield, using SIR-B, digital dataGeophysics, Vol. 59, No. 5, May pp. 733-742BrazilGeophysics -aeromagnetics, SIR-B.
DS201112-0557
2011
Taranik, J.V.Kruse,F.A., Bedell, R.L., Taranik, J.V., Peppin, W.A., Weatherbee, O., Calvin, W.M.Mapping alteration minerals at prospect, outcrop and drill core scales using imagining spectroscopy.International Journal of Remote Sensing, Vol. 33, 6, pp. 1780-1798.GlobalSpectroscopy - not specific to diamonds
DS1997-0177
1997
Tarantola, A.Chaljub, E., Tarantola, A.Sensitivity of SS precursors to topography on the upper mantle 660 KMdiscontinuity.Geophysical Res. Letters, Vol. 24, No. 21, Nov. 1, pp. 2613-16.MantleGeophysics - seismics, Discontinuity
DS201811-2553
2018
Tararin, I.A.Badredinov, Z.G., Markovsky, B.A., Tararin, I.A., Ekimova, N.I., Chubarov, V.M.Fluid silicate seperation of an ultrabasic melt into high potassium and low potassium fractions: evidence from picrites of the Late Cretaceous ultrabasic volcanic complex, eastern Kamchatka.Russian Journal of Pacific Geology, Vol. 12, 5, pp. 408-418.Russia, Kamchatkapicrites

Abstract: The mineral and chemical compositions of the layered subvolcanic ultrabasic rocks formed through fluid-silicate (liquid) separation of the ultrabasic magma into high-potassium and low-potassium fractions are characterized by the example of the layered picritic sill from the Late Cretaceous ultrabasic volcanic complex of Eastern Kamchatka. It is determined that the main potassium concentrator in the picrites from the high-potassium layers is a residual volcanic glass containing up to 8-9 wt % K2O, which is unique for ultrabasic melts.
DS200812-0338
2008
Tarasavich, B.N.Fang, L., Kononov, O.V., Marfunin, A.S., Taraevich, A.V., Tarasavich, B.N.Development of a technique for IR spectroscopic determination of nitrogen content and aggregation degree in diamond crystals.Moscow University Geology Bulletin, Vol. 63, 4, pp. 281-284.TechnologyDiamond morphology
DS200712-0629
2007
Tarasenko, V.Lipatov, E., Lisitsyn, V., Oleshko, V., Tarasenko, V.Spectral and kinetic characteristics of the pulsed cathodluminescence of a natural type IIa diamond.Russian Physics Journal, Vol. 50, 1, pp. 52-57.TechnologyDiamond IIa
DS200712-0627
2007
Tarasenko, V.F.Lipativ, E.I., Lisitsyn, V.M., Oleshko, V.I., Tarasenko, V.F.Spectral and kinetic characteristics of the pulsed cathodluminescence of a natural IIa type diamond.Russian Physics Journal, Vol. 50, 1, pp. 51-52.TechnologyDiamond - Type IIa
DS200712-0628
2007
Tarasenko, V.F.Lipativ, E.I., Lisitsyn, V.M., Oleshko, V.I., Tarasenko, V.F.Spectral and kinetic characteristics of the pulsed cathodluminescence of a natural IIa type diamond.Russian Physics Journal, Vol. 50, 1, pp. 51-52.TechnologyDiamond - Type IIa
DS2000-0620
2000
Tarasov, L.Marshall, S.J., Tarasov, L., Clarke, G., Peltier, R.Glaciological reconstruction of the Laurentide Ice Sheet: physical processes and modelling changes.Canadian Journal of Earth Sciences, Vol. 37, No.5, May pp.769-93.Ontario, CanadaGeomorphology
DS201604-0590
2015
Tarasov, O.G.Alexakhin, V.Yu., Bystritsky, V.M., Zamyatin, N.I., Zubarev, E.V., Krasnoperov, A.V., Rapatsky, V.L., Rogov, Yu.N., Sadovsky, A.B., Salamatin, A.V., Salmin, R.A., Sapozhnikov, M.G., Slepnev, V.M., Khabarov, S.V., Razinkov,E.A., Tarasov, O.G., Nikitin,G.M.Detection of diamonds in kimberlite by the tagged neutron method.Nuclear Instruments and Methods in Physics Research Section A., A785, pp. 9-13.TechnologyMethodology

Abstract: A new technology for diamond detection in kimberlite based on the tagged neutron method is proposed. The results of experimental researches on irradiation of kimberlite samples with 14.1-MeV tagged neutrons are discussed. The source of the tagged neutron flux is a portable neutron generator with a built-in 64-pixel silicon alpha-detector with double-sided stripped readout. Characteristic gamma rays resulting from inelastic neutron scattering on nuclei of elements included in the composition of kimberlite are registered by six gamma-detectors based on BGO crystals. The criterion for diamond presence in kimberlite is an increased carbon concentration within a certain volume of the kimberlite sample.
DS1986-0656
1986
Tarasov, V.S.Prokopchuk, B.I., Tarasov, V.S., et al.Pyrope and chromium diopside in terrigenous formations of the Onega RiverBasin.(Russian)Zap. Vses. Mineral. Obsch.(Russian), Vol. 115, No. 1, pp. 83-86RussiaGarnet, Mineralogy
DS201112-0924
2011
Tarassof, P.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
DS1990-1446
1990
Tarassoff, P.Tarassoff, P.Towards the year 2000. Challenges for Canada's mineral industry and the role of the The Canadian Institute of Mining, Metallurgy and Petroleum (CIM)The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 83, No. 939, July pp. 12-22CanadaThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) overview
DS1995-1417
1995
TarasyukPalkina, E.Yu., Smirnov, G.I., Ghashkin, A.I., TarasyukTypomorphism of various genetic types of the Ukrainian diamondsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 413-414.UKrainePlacers, alluvials, Diamond morphology
DS1995-1772
1995
TarasyukSmirnov, G.I., Chashka, A.I., Sobolev, N.V., TarasyukTypomorphic features of high baric minerals from kimberlites of theUkraine.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 541-542.UKraineXenoliths, Deposit -Azov
DS1995-1870
1995
Tarasyuk, O.N.Tarasyuk, O.N., Chashka, A.I., Smirnov, G.I., Lebed, N.I.Prospects of the Ukraine Territory diamondiferousnessProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 606-607.UKraineDiamond morphology, Deposit -Priazovski region
DS201112-1026
2011
TardieuTallaire, A., Barjon, J., Brinza, O., Achard, Silva, Mille, Issaoui, Tardieu, GicquelDislocations and impurities introduced from etch-pitts at the epitaxial growth resumption of diamond.Diamond and Related Materials, Vol. 20, 7, pp. 875-881.TechnologyDiamond morphology
DS1997-1138
1997
Tardley, B.W.D.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
DS201509-0431
2015
Tarduno, J.Tarduno, J.An older geomagnetic field suggests an early start to plate tectonics. ( Jack Hills)Physics.org , Aug. 3, 1p.AustraliaGeophysics - magnetics
DS1995-1871
1995
Tarduno, J.A.Tarduno, J.A.Tracking Cretaceous hotspot motionEos, Vol. 76, No. 46, Nov. 7. p.F172. Abstract.MantlePlumes
DS2003-0289
2003
Tarduno, J.A.Cottrell, R.D., Tarduno, J.A.A Late Cretaceous pole for the Pacific plate: implications for apparent polar wanderTectonophysics, Vol. 362, 1-4, pp. 321-33.GlobalTectonics, Polar wander paths
DS201012-0723
2010
Tarduno, J.A.Smironov, A.V., Tarduno, J.A.Co-location of eruption sites of the Siberian Traps and North Atlantic Igneous Province: implications for the nature of hotspots and mantle plumes.Earth and Planetary Science Letters, Vol. 297, 3-4, pp. 687-690..RussiaHotspots
DS201012-0724
2010
Tarduno, J.A.Smironov, A.V., Tarduno, J.A.Co-location of eruption sites of the Siberian Traps and North Atlantic Igneous Province: implications for the nature of hotspots and mantle plumes.Earth and Planetary Science Letters, Vol. 297, 3-4, pp. 687-690..RussiaHotspots
DS201312-0906
2013
Tarduno, J.A.Tarduno, J.A., Cottrell, R.D.Signals from the ancient geodynamo: a paleomagnetic field test on the Jack Hills metaconglomerate.Earth and Planetary Science Letters, Vol. 367, pp. 123-137.AustraliaPaleomagnetism
DS201509-0432
2015
Tarduno, J.A.Tarduno, J.A., Cottrell, R.D., Davis, W.J., Nimmo, F., Bono, R.K.A Hadean to Paleoarchean geodynamo recorded by single zircon crystals. ( Jack Hills)Science, Vol. 349, 6247, pp. 521-524.MantleGeodynamo

Abstract: Knowing when the geodynamo started is important for understanding the evolution of the core, the atmosphere, and life on Earth. We report full-vector paleointensity measurements of Archean to Hadean zircons bearing magnetic inclusions from the Jack Hills conglomerate (Western Australia) to reconstruct the early geodynamo history. Data from zircons between 3.3 billion and 4.2 billion years old record magnetic fields varying between 1.0 and 0.12 times recent equatorial field strengths. A Hadean geomagnetic field requires a core-mantle heat flow exceeding the adiabatic value and is suggestive of plate tectonics and/or advective magmatic heat transport. The existence of a terrestrial magnetic field before the Late Heavy Bombardment is supported by terrestrial nitrogen isotopic evidence and implies that early atmospheric evolution on both Earth and Mars was regulated by dynamo behavior.
DS1994-1743
1994
Tardy, M.Tardy, M., et al.The Guerrero suspect terrane (west Mexico) coeval arc terranes ( the Greater Antilles Colombia): Mesozoic intra-oceanic arc accreted to AmericaTectonophysics, Vol. 230, pp. 49-73Mexico, Colombia, CordilleraTectonics, craton, Terrane - Guerrero
DS2001-1150
2001
Tardy, M.Tardy, M., Lapierre, H/. Struik, Bosch, BrunetThe influence of mantle plume in the genesis of Cache Creek oceanic igneous rocks: geodynamic evolution...Canadian Journal of Earth Sciences, Vol. 38, No. 4, Apr. pp. 515-34.British Columbia, CordilleraMantle plume - not specific to diamonds
DS2003-0767
2003
Tardy, M.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played aChemical Geology, Vol. 201, 3-4, Nov. 14, pp. 55-89.British ColumbiaTectonics, Cache Creek, Slide Mountain Terrane, geochem
DS2003-0768
2003
Tardy, M.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played aChemical Geology, Vol. 201, 1-2, pp. 55-89.British Columbia, Yukon, Alberta, Northwest TerritoriesMagmatism, tectonics
DS200412-1077
2003
Tardy, M.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played a key role in continental crust growth.Chemical Geology, Vol. 201, 1-2, pp. 55-89.Canada, British Columbia, Yukon, Alberta, Northwest TerritoriesMagmatism, tectonics
DS200412-1078
2003
Tardy, M.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played a key role in continental crust growth.Chemical Geology, Vol. 201, 3-4, Nov. 14, pp. 55-89.Canada, British ColumbiaTectonics, Cache Creek, Slide Mountain Terrane, geochem
DS1991-1693
1991
Tardy, Y.Tardy, Y., Kobilsek, B., Paquet, H.Mineralogical composition and geographical distribution of African and Brazilian periatlantic laterites. the influence of continental drift and tropical paleoclimesJournal of Sth. African Earth Sciences, Vol. pp. 283-295Africa, Brazil, India, AustraliaLaterites, Mineralogy
DS1993-1572
1993
Tardy, Y.Tardy, Y.Petrologie des laterites et des sols tropicaux.(in French)French Geological Survey (BRGM)., 459pAfricaBook review, Laterites
DS1993-1573
1993
Tardy, Y.Tardy, Y.Petologie des laterites et des sols tropicaux. (in French)Masson Paris, 462p. $ 100.00GlobalBook - table of contents, Laterites, petrology soils
DS1997-1139
1997
Tardy, Y.Tardy, Y., Sarma, V.A.K.Petrology of laterites and tropical soilsBalkema, 500p. approx. $ 150.00Africa, Central Africa, West Africa, Ivory CoastBook - table of contents, Laterites
DS202004-0504
2020
Tarelkin, S.Chernykh, S.V., Chernykh, A.V., Tarelkin, S., Didenko, S. ,Kondakov, M.N., Shcherbachev, K.D., Trifonova, E.V., Drozdova, T.E., Troschiev, S.Y., Prikhodko, D.D., Glybin, Y.N., Chubenko, A.P., Britvich, G.I., Kiselev, D.A., Polushin, N.I., Rabinovich, O.IHPHT single crystal diamond type IIa characterization for particle detectors.Physicsa Status Solidi , doi:10.1002/pssa.201900888GlobalHPHT

Abstract: Various samples of multisectoral high-pressure high-temperature (HPHT) single-crystal diamond plate (IIa type) (4?×?4?×?0.53?mm) are tested for particle detection applications. The samples are investigated by X-ray diffractometry, photoluminescence spectroscopy, Raman spectroscopy, Fourier-transform infrared, and visible/ultraviolet (UV) absorption spectroscopy. High crystalline perfection and low impurity concentration (in the {100} growth sector) are observed. To investigate detector parameters, circular 1.0 and 1.5?mm diameter Pt Schottky barrier contacts are created on {111} and {100} growth sectors. On the backside, a Pt contact (3.5?×?3.5?mm) is produced. The {100} growth sector is proved to be a high-quality detector: the full width at half maximum energy resolution is 0.94% for the 5.489?MeV 226Ra a-line at an operational bias of +500?V. Therefore, it is concluded that the HPHT material {100} growth sector is used for radiation detector production, whose quality is not worse than the chemical vapor deposition method or specially selected natural diamond detectors.
DS201112-0397
2011
Targuisti, K.Gysi, A.P., Jagoutz, O., Schmidt, M.W., Targuisti, K.Petrogenesis of pyroxenites and melt infiltrations in the ultramafic complex of Beni Bousera, northern Morocco.Journal of Petrology, Vol. 52, 9, pp. 1679-1735.Africa, MoroccoMelting, delamination
DS201112-0398
2011
Targuisti, K.Gysi, A.P., Jagoutz, O., Schmidt, M.W., Targuisti, K.Petrogenesis of pyroxenites and melt infiltrations in the ultramafic complex of Beni Bousera, northern Morocco.Journal of Petrology, Vol. 52, 9, pp. 1679-1735.Africa, MoroccoMetasomatism
DS201212-0208
2012
Targuisti, K.Frets, E., Tommasi, A., Garrido, C.J., Padron-Navarta, J.A., Amri, I., Targuisti, K.Deformation processes and rheology of pyroxenites under lithospheric mantle conditions.Journal of Structural Geology, Vol. 39, pp. 138-157.Europe, Africa, MoroccoWebsterite, Beni-Bousera
DS201412-0253
2014
Targuisti, K.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
DS201704-0650
2016
Targuisti, K.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.
DS201707-1314
2016
Targuisti, K.Chetouani, K., Bodinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targuisti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, Vol. 348, pp. 619-629.Africa, Moroccoperidotite

Abstract: The Beni Bousera peridotite contains a diversity of pyroxenite layers. Several studies have postulated that at least some of them represent elongated strips of oceanic lithosphere recycled in the convective mantle. Some pyroxenites were, however, ascribed to igneous crystal segregation or melt–rock reactions. To further constrain the origin of these rocks, we collected 171 samples throughout the massif and examined their variability in relation with the tectono-metamorphic domains. A major finding is that all facies showing clear evidence for a crustal origin are concentrated in a narrow corridor of mylonitized peridotites, along the contact with granulitic country rocks. These peculiar facies were most likely incorporated at the mantle–crust boundary during the orogenic events that culminated in the peridotite exhumation. The other pyroxenites derive from a distinct protolith that was ubiquitous in the massif before its exhumation. They were deeply modified by partial melting and melt–rock reactions associated with lithospheric thinning.
DS201610-1850
2016
Targusiti, K.Chetoumani, K., Bondinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targusiti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, in press available 11p.Africa, MoroccoPeridotite

Abstract: The Beni Bousera peridotite contains a diversity of pyroxenite layers. Several studies have postulated that at least some of them represent elongated strips of oceanic lithosphere recycled in the convective mantle. Some pyroxenites were, however, ascribed to igneous crystal segregation or melt-rock reactions. To further constrain the origin of these rocks, we collected 171 samples throughout the massif and examined their variability in relation with the tectono-metamorphic domains. A major finding is that all facies showing clear evidence for a crustal origin are concentrated in a narrow corridor of mylonitized peridotites, along the contact with granulitic country rocks. These peculiar facies were most likely incorporated at the mantle-crust boundary during the orogenic events that culminated in the peridotite exhumation. The other pyroxenites derive from a distinct protolith that was ubiquitous in the massif before its exhumation. They were deeply modified by partial melting and melt-rock reactions associated with lithospheric thinning.
DS1983-0382
1983
Tarhovskaya, A.N.Landa, E.A., Krashnova, N.I., Tarhovskaya, A.N., Shergina, Y.P.The distribution of rare earths and yttrium in apatite from alkali-ultrabasic and carbonatite intrusions and the origin ofapatitemineralizationGeochemistry International, Vol. 20, No. 1, pp. 77-87Russia, FennoscandiaCarbonatite, Rare Earth
DS201412-0920
2014
Tarikh, S.Tarikh, S.Stornoway CEO Matt Manson's path to Renard. Quebec's first diamond mine slated to open in 2017.Diamonds in Canada Magazine, Northern Miner, November pp. 8-11.Canada, QuebecHistory of Renard
DS2000-0393
2000
tarits, P.Hautot, S., tarits, P., Le Turdu, C.Deep structure of the Baringo Rift Basin from three dimensional magnetotelluric imaging: rift evolution.Journal of Geophysical Research, Vol. 105, No.B 10, Oct.10, pp.23493-518.KenyaGeophysics - magnetotellurics, Tectonics - rifting
DS200912-0795
2009
Tarits, 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
DS1996-0995
1996
Tarling, D.H.Morris, A., Tarling, D.H.Paleomagnetism and tectonics of the Mediterranean regionGeological Society of London Special Publication, No. 105, 430pGlobalPaleomagnetics, tectonics, Table of contents
DS1997-1140
1997
Tarlowksi, C.Tarlowksi, C., Gunn, P.J., Mackey, T.Enhancements of the magnetic map of AustraliaAgso Journal, Australian Geology And Geophysics, Vol. 17, No. 2, pp. 77-82AustraliaGeophysics - airborne, Geophysics - magnetics
DS1996-1400
1996
Tarlowski, C.Tarlowski, C., McEwin, A.J., Reeves, C.V., Barton, C.E.Dewarping the composite aeromagnetic anomaly map of Australia using controltraverses and base stationsGeophysics, Vol. 61, No. 3, May-June pp. 696-705AustraliaGeophysics -aeomagnetics, Composite anomaly map
DS201012-0714
2010
Tarnavsky, A.V.Simonov, V.A., Prikhodko, V.S., Kovyazin, S.V., Tarnavsky, A.V.Crystallization conditions of dunites in the Konder platiniferous alkaline ultramafic massif of the southeastern Aldan Shield.Russian Journal of Pacific Geology, Vol. 4, 5, pp. 429-440.Russia, Aldan ShieldAlkalic
DS1980-0299
1980
Tarney, J.Saunders, A.D., Tarney, J., Weaver, S.D.Transverse geochemical variations across the Antarctic Peninsula:implications for the genesis of calc alkaline magmas.Earth and Planetary Science Letters, Vol. 46, pp. 344-60.AntarcticaAlkaline Rocks, Geochemistry
DS1985-0716
1985
Tarney, J.Weaver, B.L., Wood, D.A., Tarney, J., Joron, J.L.Geochemical Nature of Mantle Sources of Atlantic Ocean Island Basalts.Conference Report of The Meeting of The Volcanics Studies Gr, 1P. ABSTRACT.GlobalIsotope, Petrography
DS1988-0610
1988
Tarney, J.Saunders, A.D., Norry, M.J., Tarney, J.Origin of Mid Ocean Ridge Basalt (MORB) and chemically depleted mantlereservoirs: trace elementconstraintsJournal of Petrology, Special Volume 1988- Oceanic and Continental, pp. 415-445GlobalMantle, Geochemistry
DS1989-0606
1989
Tarney, J.Heaman, L.M., Tarney, J.uranium-lead (U-Pb) (U-Pb) baddeleyite ages for the Scourie dyke swarm,Scotland: evidence for two distinct intrusion eventsNature, Vol. 340, August 31, pp. 705-708ScotlandDyke, Age determination -picrit
DS1990-1447
1990
Tarney, J.Tarney, J., Pickering, K.T., Knipe, R.J., Dewey, J.F.The behaviour and influence of fluids in subduction zonesPhil. Transactions Royal Soc. London, Vol. 335, pp. 225-418GlobalMagmas, Subduction zones
DS1991-1501
1991
Tarney, J.Saunders, A.D., Norry, M.J., Tarney, J.Fluid influence on the trace element compositions of subduction zonemagmasPhil. Transactions R. Soc. London, Sect. A., Vol. 335, pp. 377-392GlobalTectonics, Geochemistry - trace elements
DS1992-1519
1992
Tarney, J.Tarney, J.Geochemistry and significance of mafic dyke swarms in the ProterozoicProterozoic Crustal Evolution, K.C. Condie, Developments in Precambrian, Chapter 4, pp. 151-180.MantleDyke swarms, Mantle plumes
DS1994-0765
1994
Tarney, J.Hergt, J.M., Storey, M., Marriner, G., Tarney, J.Trace element and isotopic compositions of the picritic rocks from CuracaoIsland.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 94-96.GlobalGeochemistry, Picrites
DS1994-1744
1994
Tarney, J.Tarney, J., Jones, C.E.Trace element geochemistry of orogenic igneous rocks and crustal growthmodels.Journal of the Geological Society of London, Vol. 151, No. 5, Sept. pp. 855-868.GlobalGeochemistry, Igneous rocks
DS1995-0251
1995
Tarney, J.Cadman, A.C., Tarney, J., Baragar, W.R.A.Nature of mantle source contributions, role of contamination, in situcrystallization in petrogenesisContributions to Mineralogy and Petrology, Vol. 122, No. 3, pp. 213-229LabradorProterozoic mafic dykes, Flood basalts
DS1995-0940
1995
Tarney, J.Kerr, A.C., Saunders, A.D., Tarney, J., Berry, N.H., Hards, V.L.Depleted mantle plume geochemical signatures: no paradox for plumetheoriesGeology, Vol. 23, No. 9, Sept. pp. 843-846MantlePlumes, Geochemistry
DS1995-1386
1995
Tarney, J.Oliveira, E.P., Tarney, J.Petrogenesis of the late Proterozoic Curaca mafic dyke swarm, asthenospheric magmatism assoc with collision.Mineralogy and Petrology, Vol. 53, No. 1-3, pp. 27-48.BrazilDike swarm, Mantle
DS1995-1387
1995
Tarney, J.Oliveira, E.P., Tarney, J.Petrogenesis of Late Proterozoic Curaca mafic dyke swarm:asthenospheric magmatism Association collisionMineralogy and Petrology, Vol. 53, No. 1-3, pp. 27-48BrazilMafic magmatism
DS1995-1388
1995
Tarney, J.Oliviera, E.P., Tarney, J.Petrogenesis of the late Proterozoic Curaca mafic dyke swarm:asthenospheric magmatism Association cont. collisionMineralogy and Petrology, Vol. 53, pp. 27-48BrazilDyke swarms, Magmatism
DS1996-0729
1996
Tarney, J.Kerr, A.C., Tarney, J., Thirwall, M.F.The geochemistry and petrogenesis of the late Cretaceous picrites and basalts of Curacao, Antilles.Contributions to Mineralogy and Petrology, Vol. 124, No. 1, pp. 29-43.GlobalPicrites, Alkaline rocks
DS1996-1252
1996
Tarney, J.Saunders, A.D., Tarney, J., Kent, R.W.The formation and fate of large oceanic igneous provincesLithos, Vol. 37, No. 2/3, April pp. 81-96GlobalIgneous, Basalts
DS1997-0042
1997
Tarney, J.Arndt, N.T., Kerr, A.C., Tarney, J.Dynamic melting in plume heads; the formation of Gorgona komatiitebasaltsEarth and Planetary Science Letters, Vol. 146, No. 1-2, Jan. 1, pp. 289-302GlobalMantle plumes, Komatiites
DS2002-0830
2002
Tarney, J.Kerr, A.C., Aspden, J.A., Tarney, J., Pilatasig, L.F.The nature and provenance of accreted oceanic terranes in western Ecuador: geochemical and tectonic constraints.Journal of the Geological Society of London, Vol. 159, 5, pp. 577-594.EcuadorBlank
DS2002-1693
2002
Tarney, J.Weber, M.B.I., Tarney, J., Kempton, P.D., Kent, R.W.Crustal makeup of the northern Andes: evidence based on deep crustal xenolith suites, Mercaderes, SW Colombia.Tectonophysics, Vol.345, 1-4, Feb.15, pp. 49-82.ColombiaGeodynamics - tectonics, Xenoliths
DS200412-0988
2002
Tarney, J.Kerr, A.C., Aspden, J.A., Tarney, J., Pilatasig, L.F.The nature and provenance of accreted oceanic terranes in western Ecuador: geochemical and tectonic constraints.Journal of the Geological Society, Vol. 159, 5, pp. 577-594.South America, EcuadorGeochemistry, tectonics
DS200812-0007
2008
Tarney, J.Ahmad, T., Deb, M., Tarney, J., Raza, M.Proterozoic mafic volcanism in the Aravalli Delhi orogen, northwest India: geochemistry and tectonic framework.Journal of Geological Society of India, Vol. 72, 1, pp. 93-112.IndiaTectonics
DS1993-0702
1993
Tarnocai, C.Hughes, O.L., Tarnocai, C., Schweger, C.E.Pleistocene stratigraphy, paleopedology and paleoecology of a multiple till sequence exposed on the Little Bear River, western district of Mackenzie, northwest Territories.Canadian Journal of Earth Sciences, Vol. 30, No. 4, April pp. 851-866Northwest TerritoriesGeomorphology, Physiography western district of Mackenzie
DS1975-0154
1975
Tarnovskaya, A.N.Olagulkina, V.H., Tarnovskaya, A.N.Perovskite from Yakutian KimberlitesZap. Vses. Mineral. Obshch., Vol. 104, PP. 703-710.RussiaBlank
DS1991-0221
1991
Taroni, G.Carbognin, L., Taroni, G.Correlation between percentage matrices - a new approachComputers and Geosciences, Vol. 17, No. 4, pp. 477-488GlobalComputers, Correlation matrices
DS2002-0058
2002
Tarquini, S.Armienti, P., Tarquini, S.Power law olivine crystal size distributions in lithospheric mantle xenolithsLithos, Vol. 65, 3-4, Dec. pp. 273-85.MantleCrystallography, xenoliths
DS2002-0059
2002
Tarquini, S.Armienti, P., Tarquini, S.Power law olivine crystal size distribution in lithospheric mantle xenolithsLithos, Vol. 65, 3-4, pp. 273-85.MantleXenoliths - olivine crystallography, morphology
DS1930-0150
1933
Tarr, W.A.Tarr, W.A., Kellor, W.D.A Post-devonian Intrusion in Southeastern MissouriJournal of Geology, Vol. 41, PP. 815-823.Missouri, United States, Central StatesAlnoite, Related Rocks
DS1930-0205
1935
Tarr, W.A.Tarr, W.A.The Origin of the Decaturville Dome, Camden County, MissouriMissouri Academy of Science Proceedings, Vol. 1, PP. 99-10L.GlobalKimberlite, Central States, Cryptoexplosion
DS1998-1442
1998
Tarras-Wahlberg, H.Tarras-Wahlberg, H.Marine diamond mining and the environmentRaw Materials Report, Vol. 13, No. 1, pp. 6-16.South Africa, Namaqualand, Orange RiverMarine mining, Geomorphology, mining methods
DS200812-1104
2008
Tarskhix, O.Y.Spetsius, Z.V., Zezekalo, M., Yu, Tarskhix, O.Y.Pecularities of mineralogy and petrography of the upper Muna field kimberlites: application to the lithospheric mantle composition.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 137-146.Russia, SiberiaDeposit - Muna field
DS201802-0269
2017
Tarskikh, E.V.Tomshin, M.D., Pokhilenko, N.P., Tarskikh, E.V.Morphology of the Nyurba kimberlite pipe and its relationship with the dolerite dike.Doklady Earth Sciences, Vol. 477, 2, pp. 1458-1460.Russiadeposit - Nyturba

Abstract: Study of the magmatics in the Nakyn kimberlite field, with consideration of the isotope dating results, allowed us to establish a sequence of their formation. First, 368.5-374.4 Ma ago intrusions of the Vilyui-Markha dike belt formed. Then (363-364 Ma) intrusion of kimberlites took place. In the Early Carboniferous (338.2-345.6 Ma), alkaline basaltic magma intruded through faults controlling the kimberlites. The magmatic activity finished 331-324.9 Ma ago with the formation of explosive breccias. It has been found that the Nyurba kimberlite pipe consists of two bodies: their kimberlite melts have successively intruded through independent channels.
DS200612-1180
2005
Tarskikh, O.V.Rotman, A.Y., Bogush, I.N., Tarskikh, O.V.Kimberlites of Yakutia: standard and anomalous indications.Problems of Sources of deep magmatism and plumes., pp. 114-147.Russia, YakutiaMineral chemistry
DS201312-0874
2012
Tarskikh, O.V.Spetsius, Z.V., Kornilova, V.P., Tarskikh, O.V.Pecularities of petrography and mineralogy kimberlites from deep levels of the Internationalaya pipe.Vladykin, N.V. ed. Deep seated magmatism, its sources and plumes, Russian Academy of Sciences, pp. 204-225.RussiaDeposit - Internationalaya
DS201412-0877
2014
Tarskix, O.V.Spetsius, Z.V., Polyanichko, V.V., Xarlamova, E.I.,Tarskix, O.V., Ivanov, A.S.Geology, petrography and mineralogy of the Zarya pipe kimberlites.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 160-177.RussiaDeposit - Zarya
DS201510-1807
2014
Tarskix, O.V.Spetsius, Z.V., Polyanichko, V.V., Xarlamova, E.I., Tarskix, O.V., Ivanov, A.S.Geology, petrography and mineralogy of the Zarya pipe kimberlites.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 160-177.RussiaDeposit - Zarya
DS201511-1886
2015
Tarum, A.Tarum, A., Lee, S.J., Yap, C.M., Finkelstein, K.D., Misra, D.S.Impact of impurities and crystal defects on the performance of CVD diamond detectors.Diamond and Related Materials, in press available, 6p.TechnologySynthetics - Radiation detectors

Abstract: Radiation detectors based on diamond are highly favored for particle physics research due to the superior radiation hardness. In this work, we investigate the influence of impurities and crystalline imperfections on the charge collection efficiency (CCE) of single crystal diamond. Seventeen (17) ultra-low fluorescent diamond samples grown by microwave plasma chemical vapor deposition method from IIa Technologies PTE LTD are pre-selected for this study. The measured CCE of all samples using 241Am (a-particles) as ionizing source are analyzed together with the concentration of trace impurities and crystalline imperfection in the crystal. The amounts of impurities are quantified from integrated fluorescence intensity arising from the nitrogen vacancies (NV) created during different CVD growth process conditions. The crystal imperfections are assessed by X-ray rocking curves from X-ray topography images obtained at the Cornell High Energy Synchrotron Source. The CCE decays rapidly as the intensity of NV (INV), phonon sideband approaches that of diamond 2nd order Raman peak which follows the relation: View the MathML sourceCCEINV=100/1+INV1.052. The energy resolution, ?E/E (ratio of the energy spectrum width to the most probable peak) highly correlates with broader rocking curve width distribution. Prime novelty statement: This work provides an understanding on the most important factors that contribute to degradation of charge collection efficiency (CCE) in diamond based detectors and sensors. The CCE decays rapidly as the intensity of nitrogen vacancy phonon sideband approaches that of diamond 2nd order Raman peak which follows the relation: View the MathML sourceCCEINV=100/1+INV1.052. The energy resolution, that is the ratio of the energy spectrum width to the most probable peak, highly correlates with broader X-ray rocking curve width distribution.
DS201511-1889
2015
Tarum, A.Yap, C.M., Tarum, A., Xiao, S., Misra, D.S.MPCVD growth of 13 C-enriched diamond single crystals with nitrogen addition.Diamond and Related Materials, in press available, 29p.TechnologySynthetics - nitrogen

Abstract: This study describes the growth of 13C-enriched (100)-oriented diamond single crystals by the MPCVD (microwave plasma chemical vapour deposition) process. All crystals are at least 6 × 6 mm2 in area and 0.5-1.0 mm in thickness. The samples with nominal 13C percentages (R = [13C] / [13C + 12C]) of 0.011 (natural abundance), 0.10, 0.21, 0.24 and 0.34 were obtained by controlling the flow of the carbon-13 and carbon-12 methane feed gases. To obtain thicker and near-colourless quality 13C-enriched diamond, 190 ppm of nitrogen was added into the gas mixture. The shift towards lower frequency in the Raman peak positions and decrease in the thermal conductivities of the near-colourless crystals with increasing 13C percentages are similar to previous studies of isotopically-controlled diamond grown with no nitrogen additive. The images of the structural defects associated with 13C-enrichment obtained by spatially-resolved X-ray rocking curve measurement show distinct patterned structures that runs parallel to the < 100 > direction. Moreover, the broadening in the line width of the nuclear magnetic resonance (NMR) peak from sp313C correlates with increasing R. We also expand the study by injecting 500 ppm of nitrogen. Higher nitrogen concentration leads to the formation of brown crystals. The brown crystals show far greater 13C NMR peak intensity than the near-colourless. This suggests that paramagnetic nitrogen impurities in the brown crystals hasten the spin-lattice relaxation time of the 13C nuclear spin that resulted in higher intensity. The isotopic splitting observed for the localized vibrational mode of the NVH0 defect in brown crystals is attributed to the co-existence of both the 13C (3114.2 cm- 1) and 12C (3123.5 cm- 1). Unlike the isotopic splitting observed for NVH0 defect, the peak position of the Ns+ defect shifts towards lower frequency as R increases. Not only have we demonstrate the growth of bigger isotopically-controlled diamond single crystals, the results shown here have provided a framework to further investigate the interplay between 13C atoms and nitrogen impurity.
DS1995-1538
1995
Tarvainen, T.Raisanen, M.L., Tarvainen, T., Aaros, S.NORMA - a program to calculate a normative mineralogy for glacial tills and rocks from chemical analysis.Gff., Vol. 117, pp. 215-224.GlobalGeomorphology, Computer Program - NORMA.
DS1995-1872
1995
Tarvainen, T.Tarvainen, T.The geochemical correlation between coarse and fine fractions of till in southern FinlandJournal of Geochemical Exploration, Vol. 54, No. 3, November pp. 187-198FinlandGeochemistry, Till fractions
DS1996-0845
1996
Tarvainen, T.Licht, O.A.B., Tarvainen, T.Multipurpose geochemical maps produced by integration of geochemical exploration dat a sets Parana ShieldJournal of Geochem. Explor, Vol. 56, No. 3, Nov. pp. 167-182BrazilGeochemistry - maps, Sulphides
DS1993-0884
1993
Tarzey, R.J.E.Latin, D., Norry, M.J., Tarzey, R.J.E.Magmatism in the Gregory Rift, East Africa: evidence for melt generation bya plume.Journal of Petrology, Vol. 24, No. 5, October pp. 1007-1028.TanzaniaTectonics, Magmatism
DS201112-0950
2011
TasaharaShestakov, N.V., Gerasimenko, Takalhashi, Tasahara, Bormotov, Bykov,Kolomiets et al.Present tectonics of the southeast of Russia as seen from GPS observations.Geophysical Journal International, Vol. 184, 2, pp. 529-540.RussiaGeodynamics
DS200812-1155
2008
Tasaka, M.Tasaka, M., Michibayashi, K., Mainprice, D.B type olivine fabrics developed in the fore-arc side of the mantle wedge along a subducting slab.Earth and Planetary Science Letters, Vol. 272, 3-4, pp. 747-757.MantleSubduction
DS200712-1070
2006
Tashey, T.E.Jr.Tashey, T.E.Jr., Tahey, M.C.A system to describe the face up color appearance of white and off white polished diamonds.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.142-3. abstract onlyTechnologyDiamond colour grading
DS1995-1281
1995
Tashin, A.P.Mitrofanov, G.I., Tashin, A.P.Structural relations of the Siberian platform with its folded frameGeotectonics, Vol. 28, No. 1, August pp. 1-12.Russia, SiberiaTectonics, Structure -Platform
DS201312-0249
2013
Tasinari, C.C.G.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
DS1986-0524
1986
Taskaev, V.I.Maraukshev, A.A., Taskaev, V.I.Composition variations in minerals from garnetiferous peridotites and eclogites and their genetic significance.(Russian)Izv. Vyssh. Uchebn. Zaved. Geol. Razved., (Russian), No. 5, pp. 9-41RussiaEclogite
DS1989-1479
1989
Taskayev, V.I.Taskayev, V.I., Ilupin, I.P.Clinohumite from kimberlites; chemical composition and the specific of isomorphic replacements.(Russian)Mineral. Zhurnal, (Russian) Akad. Nauk SSSR, Dal'nevost. Geol. Inst, Vol. 11, No. 6, pp. 29-38RussiaGeochemistry, Humite group
DS1990-1448
1990
Taskayev, V.I.Taskayev, V.I.Association of clinohumite and K-richterite In kimberlite of Kollektivnaya pipe.(Russian)Doklady Academy of Sciences Nauk. SSSR, (Russian), Vol. 310, No. 3, pp. 683-686RussiaKollektivnaya pipe, Mineralogy
DS1991