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SDLRC - Scientific Articles all years by Author - D-Dd


The Sheahan Diamond Literature Reference Compilation
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcementscalled the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Resource Center
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Media/Corporate References by Name for all years
A B C D-Diam Diamonds Diamr+ E F G H I J K L M N O P Q R S T U V W X Y Z
Tips for Users
Posted/Published Reference CodesThe SDLRC provides 3 types of references identified in the reference code. DS for scientific article, DM for a media article, and DC for a corporate announcement. Consider DS0512-0001. The DS stands for "diamond scientific". 05 stands for 2005, the year the reference was posted. 12 represents the month the reference was posted. For all years prior to 2015 the default month is 12. -0001 is the reference's identifier and it does not mean anything. The number below the refence code, ie 2015, is the year the article was published. Note that the posted year may sometimes be later than the published year.
Sort OrderReferences are sorted by the "author" name and when the reference was posted to the compilation.
Most RecentIf the reference code is highlighted yellow, the reference was made available through the most recent monthly compilation of new literature. Use this to check out new references. When new references are posted, we make it our priority to track down an online link and obtain an abstract. With regard to older references, tracking down an abstract and an online link is a work in progress.
Link to external location of article: If the title has a link, it means we have found a location online where you can either retrieve the full article free, or purchase access to it. The Sheahan Diamond Literature Service is not a technical article procurement service; if you want a restricted article, you must deal directly with the vendor who controls the copyright to the article.
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Author Index
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years - D-Dd
Posted/
Published
AuthorTitleSourceRegionKeywords
DS202008-1429
2020
DPalmato, M.G., Nestola, F., Novella, D, Pearson, D.G., Stachel, T.In-situ mineralogical characterization of sulphide inclusions in diamonds.Goldschmidt 2020, 1p. AbstractCanada, Ontariodeposit - Victor

Abstract: Among mineral inclusions in diamond, sulphides are the most abundant. Also, they are the keel tool for dating diamond formation given their high concentration of highlysiderophile elements. However, the mineralogical nature of these inclusions is not well understood, mainly due to the exsolution of the original, high temperature monosulphide solid solution (Mss) to Fe-, Ni- and Cu-rich endmembers during cooling, obscuring the original composition. This complex exsolution observed in sulphide inclusions in diamonds can also cause problems with Re-Os age determinations if the whole inclusion is not extracted. To overcome this issue, recently, sulphide inclusions have been homogenized at high temperature and controlled oxygen fugacity [1]. However, X-ray diffraction or Raman spectroscopy analyses, required to accurately identify the inclusion phases, and define their degree of crystallographic plus compositional homogeneity, have not been reported. Here we combine for the first time a thorough nondestructive multi-technique characterization of sulphide inclusions in diamonds from the Victor Mine (Canada) with homogenization experiments and isotopic analyses. In particular, we report X-ray diffraction data of the sulphides before and after homogenization, confirming a change from a polycrystalline assemblage of pyrrothite, pentlandite and chalcopyrite to single-crystal Mss. The data are used to reconstruct the Mss’ original bulk composition, define the true bulk isotopic ratios and document any difference in Re- Os isotope systematics.
DS2003-1069
2003
D' Agrilla FilhoPersonen, L.J., Elming, Mertansen, Pisarvesky, D' Agrilla Filho, Meert, SchmidtPaleomagnetic configuration of continents during the ProterozoicTectonophysics, Vol. 375, 1-4, pp. 289-324.MantleMagnetics
DS200412-1532
2003
D' Agrilla FilhoPersonen, L.J., Elming, Mertansen, Pisarvesky, D' Agrilla Filho, Meert, Schmidt, Abrahamsen, BylundPaleomagnetic configuration of continents during the Proterozoic.Tectonophysics, Vol. 375, 1-4, pp. 289-324.MantleMagnetics
DS202003-0367
2020
D.Turetsky, M.R., Abbott, B.W., Jones, M.C., Walter Anthony, K.. Olefeldt, D., Schuur, E.A.G., Grosse, G., Kuhry, P., Higelius, G., Koven, C., Lawrence, D.M., Gibson, C., Sannel, A.B.K., McGuire, A.D.Carbon release through abrupt permafrost thaw. ( not specific to diamonds but interest)Nature Geoscience, Vol. 13, pp. 138-143.Mantlecarbon

Abstract: The permafrost zone is expected to be a substantial carbon source to the atmosphere, yet large-scale models currently only simulate gradual changes in seasonally thawed soil. Abrupt thaw will probably occur in <20% of the permafrost zone but could affect half of permafrost carbon through collapsing ground, rapid erosion and landslides. Here, we synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance. Emissions across 2.5?million?km2 of abrupt thaw could provide a similar climate feedback as gradual thaw emissions from the entire 18?million?km2 permafrost region under the warming projection of Representative Concentration Pathway 8.5. While models forecast that gradual thaw may lead to net ecosystem carbon uptake under projections of Representative Concentration Pathway 4.5, abrupt thaw emissions are likely to offset this potential carbon sink. Active hillslope erosional features will occupy 3% of abrupt thaw terrain by 2300 but emit one-third of abrupt thaw carbon losses. Thaw lakes and wetlands are methane hot spots but their carbon release is partially offset by slowly regrowing vegetation. After considering abrupt thaw stabilization, lake drainage and soil carbon uptake by vegetation regrowth, we conclude that models considering only gradual permafrost thaw are substantially underestimating carbon emissions from thawing permafrost.
DS201907-1551
2019
D;Haenens-Johansson, U.F.S.Howell, D., Collins, A.T., Loudin, L.C., Diggle, P.L., D;Haenens-Johansson, U.F.S., Smit, K.V., Katrusha, A.N., Butler, J.E., Nestola, F.Automated FTIR mapping of boron distribution in diamond. Type IlbDiamond and Related Materials, in press available 33p.GlobalDiaMap

Abstract: Type IIb diamonds are those that contain more boron than nitrogen. The presence of this uncompensated boron gives rise to absorption in the infrared part of the electromagnetic spectrum, extending into the visible region and often resulting in blue colouration. Here we report on the expansion of the DiaMap freeware (for the automated spectral deconvolution of Type I [nitrogen containing] diamonds) to work on Type IIb diamonds, returning concentrations from three boron-related absorption bands, and determining which band provides the most reliable value. The program uses the calibration coefficients of Collins (2010), which show good relative agreement between the three bands, but might require some further study to confirm their absolute accuracy to the uncompensated boron concentration. The methodology of DiaMap_IIb is applicable to all Type IIb diamonds, both natural and synthetic. Analysis of high-resolution Fourier-transform infrared (FTIR) maps of two high-pressure high-temperature (HPHT) synthetic diamonds using DiaMap_IIb, confirm the growth sector dependence of the boron incorporation. Partitioning of boron strongly favours the octahedral {111} sectors.
DS1989-0886
1989
da Costa, M.Limas, da Costa, M.The use of rare earth element geochemistry to discriminate the laterite derivation in the Gurupiregion (eastern Amazonia)Xiii International Geochemical Exploration Symposium, Rio 89 Brazilian Geochemical, pp. 69-70BrazilCarbonatite, Weathering
DS200612-0301
2006
Da Costa, P.C.C.Da Costa, P.C.C., Girardi, V.A.V., Teixeira, W.40 Ar 39Ar and Rb Sr geochronology of the Goias Crixas dike swarm, central Brazil: constraints on the Neoarchean Paleoproterozoic tectonic boundary...International Geology Review, Vol. 48, 6, pp. 547-560.South America, BrazilGeochronology, subcontinental mantle
DS1999-0158
1999
Da Costa Campos Neto, M.Da Costa Campos Neto, M., Caby, R.Neoproterozoic high pressure metamorphism and tectonic constraint from the Nappe system south Sao Francisco...Precambrian Research, Vol. 97, pp. 3-26.BrazilCraton - Sao Francisco, Tectonics, collision
DS1992-1155
1992
Da Costra, J.M.Padilha, A.L., Trivedi, N.B., Vitorello, I., Da Costra, J.M.Upper crustal structure of the northeast Parana Basin, Brasil, determined from integrated magnetotelluric and gravity measurementsJournal of Geophysical Research, Vol. 97, No. B3, March 10, pp. 3351-3366BrazilStructure, Crust
DS1997-1202
1997
Da Matta Ponte, K.Vaughan, W.S., Bourassa, M.J., Da Matta Ponte, K.Establishing a mineral regime conducive to exploration investmentPros. and dev. Association Canada, March pp. 46-53CanadaLegal - regulatory, Economics - mining
DS200512-1137
2004
Da NorbregaVentura Santos, R., Souza de Alvarenga, C.J., Babinski, M., Ramos, M.L.S., Cukrov, N., Fonsec, M.A., Da NorbregaCarbon isotopes of Mesoproterozoic Neoproterozoic sequences from southern Sao Francisco craton and Aracuai Belt, Brazil: paleogeorgraphic implications.Journal of South American Earth Sciences, Vol. 18, 1, Dec. 30, pp. 27-39.South America, BrazilGeomorphology, glaciation, geochronology,carbonatites
DS1998-0290
1998
Da Pinho Guimardes, I.Da Pinho Guimardes, I., da Silva Filho, A.neodymium-Strontium isotopic and uranium-lead (U-Pb) geochronologic constraints for evolution of the shoshonitic Brasiliano Bom Jardim ..International Geological Review, Vol. 40, No. 6, June pp. 500-527BrazilAlkaline rocks, Transamazonian mantle, geochronology, Bom Jardim, Toritama
DS201911-2518
2019
da Rocha, A.M.R.de Almeida Morales, B.A., de Almeida, D.D.P.M., Koester, E., da Rocha, A.M.R., Dorneles, N.T., da Rosa, M.B., Martins, A.A.Mineralogy, whole-rock geochemistry and C, O isotopes from Passo Feio carbonatite, Sul-Riograndense shield, Brazil.Journal of South American Earth Sciences, Vol. 94, 102208 13p. PdfSouth America, Brazilcarbonatite

Abstract: Carbonatites are peculiar igneous rocks, consisting mainly of greater than 50% carbonate minerals, which arouse an economic interest due to the potentiality of high phosphate content and Light Rare Earth Elements (LREE) associated with their occurrence. The Passo Feio Carbonatite (PFC) is located 17?km Southwest of Caçapava do Sul city and constitutes NW dipping body, which is interposed with Passo Feio Formation metamorphic rocks. The PFC varies texturally from massive to foliated, being mainly composed of calcites and dolomites and on a smaller scale by apatites, phlogopites and tremolites. The opaque minerals correspond to hematites, magnetites, pyrites and barites, while the accessory minerals are represented by zircons, monazites- (Ce) and aeschynites- (Ce). Probably those REE mineral phases correspond to a hydrothermal stage, with the REE remobilization from apatites into those latter REE-rich mineral phases - this hypothesis is corroborated by geochemistry, mineral chemistry and microtextures found. Considering the results of mineral chemistry and taking into account the textural criteria, it was possible to classify carbonatite as an alvikite, with geochemical patterns that do not indicate economic potential for REE. However, soil geochemistry showed an important enrichment in REE, reflecting a probable concentration of monazites- (Ce) and aeschynites- (Ce), and because of this, it was possible to establish a zone in which the Passo Feio Carbonatite would probably be extended. In the stable isotope analyzes, the d13C values varied between -4.14 and -3.89‰ while those of d18O between 10.01 and 11.32‰ which can be attributed to the cooling of the magma itself, without suggesting metamorphic processes or subsequent changes. The deformation found in this carbonatite was probably developed in late-magmatic conditions, guided by tectonics associated with horizontal movements in shear zones. Thus, this work suggests that this carbonatite was the product of the reactivation of mantle sources, within a post-collision magmatic context of the Sul-Riograndense Shield.
DS202002-0177
2019
da Rocha Ribeiro, R.de Mamam Anzolin H., Dani, N., Remus, M.V.D., da Rocha Ribeiro, R., Nunes, A.R., Ruppel, K.M.V.Apatite multi-generations in the Tres Estradas carbonatite, southern Brazil: physical and chemistry meaning and implications to phosphate ore quality. Brazil Journal of Geology ( www.scielo.br) ENG, 17p. PdfSouth America, Brazildeposit - Tres Estradas

Abstract: Carbonatites were recently discovered in Southern Brazil, which increased the interest to evaluate the economic potential of these uncommon rocks, especially the Três Estradas Carbonatite. Carbonates are the dominant minerals of fresh rock followed by apatite, but the weathering process makes apatite abundant. We focused on apatite from the carbonatite using conventional petrography and electronic microscopy associated with microprobe, micro-Raman and Fourier-transform infrared spectroscopy. Results demonstrate the existence of four types. The primary type is associated with the rock crystallization and the subsequent three others are associated with weathering processes. The alteration mechanism was favorable for initial carbonate leaching and subsequent increase of phosphate with late precipitation of three new apatite generations. The deduced model involves long exposure during polycyclic climate changes, intercalating periods of warm dry with humid climate. The apatite types differ chemically and morphologically and have distinctive characteristics that are suitable to be used to differentiate them. These properties should be considered in future planes of industrial processes to transform apatite into single superphosphate, a basic input for fertilizer production.
DS201809-2055
2018
da Ros Costa, L.T.Leal, R.E., Lafon, J.M., da Ros Costa, L.T., Dantas, E.L.Orosirian magmatic episodes in the erepercuru-trombetas domain ( southeastern Guyana shield: implications for the crustal evolution of the Amazonian craton.South American Earth Sciences, Vol. 85, pp. 278-297.South America, Guyanacraton - Amazonian
DS201911-2518
2019
da Rosa, M.B.de Almeida Morales, B.A., de Almeida, D.D.P.M., Koester, E., da Rocha, A.M.R., Dorneles, N.T., da Rosa, M.B., Martins, A.A.Mineralogy, whole-rock geochemistry and C, O isotopes from Passo Feio carbonatite, Sul-Riograndense shield, Brazil.Journal of South American Earth Sciences, Vol. 94, 102208 13p. PdfSouth America, Brazilcarbonatite

Abstract: Carbonatites are peculiar igneous rocks, consisting mainly of greater than 50% carbonate minerals, which arouse an economic interest due to the potentiality of high phosphate content and Light Rare Earth Elements (LREE) associated with their occurrence. The Passo Feio Carbonatite (PFC) is located 17?km Southwest of Caçapava do Sul city and constitutes NW dipping body, which is interposed with Passo Feio Formation metamorphic rocks. The PFC varies texturally from massive to foliated, being mainly composed of calcites and dolomites and on a smaller scale by apatites, phlogopites and tremolites. The opaque minerals correspond to hematites, magnetites, pyrites and barites, while the accessory minerals are represented by zircons, monazites- (Ce) and aeschynites- (Ce). Probably those REE mineral phases correspond to a hydrothermal stage, with the REE remobilization from apatites into those latter REE-rich mineral phases - this hypothesis is corroborated by geochemistry, mineral chemistry and microtextures found. Considering the results of mineral chemistry and taking into account the textural criteria, it was possible to classify carbonatite as an alvikite, with geochemical patterns that do not indicate economic potential for REE. However, soil geochemistry showed an important enrichment in REE, reflecting a probable concentration of monazites- (Ce) and aeschynites- (Ce), and because of this, it was possible to establish a zone in which the Passo Feio Carbonatite would probably be extended. In the stable isotope analyzes, the d13C values varied between -4.14 and -3.89‰ while those of d18O between 10.01 and 11.32‰ which can be attributed to the cooling of the magma itself, without suggesting metamorphic processes or subsequent changes. The deformation found in this carbonatite was probably developed in late-magmatic conditions, guided by tectonics associated with horizontal movements in shear zones. Thus, this work suggests that this carbonatite was the product of the reactivation of mantle sources, within a post-collision magmatic context of the Sul-Riograndense Shield.
DS200612-0302
2006
Da Rosa Costa, L.Da Rosa Costa, L., Lafon, J.M., Delor, C.Zircon geochronology and Sm Nd isotopic study: further constraints for the Archean and Paleoproterozoic geodynamical evolution of southe eastern Guiana Shield.Gondwana Research, Vol. 10, 3-4, pp. 277-300.South America, GuyanaGeochronology
DS201903-0502
2019
da Silva, B.V.da Silva, B.V., Hackspacher, P.C., Siqueira Riberio, M.C., Glasmacher, U.A., Goncalves, A.O., Doranti-Tiritan, C., de Godoy, D.F., Constantino, R.R.Evolution of the southwestern Angolan margin: episodic burial and exhumation is more realistic than long term denudation.International Journal of Earth Sciences, Vol. 108, pp. 89-113.Africa, Angolathermochronology

Abstract: There are two main points of view regarding how continental margins evolve. The first one argues that the present-day margins have been developed by long-term denudation since a major exhumation episode, probably driven by rifting or another relevant tectonic event. The second one argues that continental margins underwent alternating burial and exhumation episodes related to crustal tectonic and surface uplift and subsidence. To demonstrate that the proximal domain of the southwestern Angolan margin has evolved in a polycyclic pattern, we present a review of geological and thermochronological information and integrate it with new combined apatite fission-track and (U-Th)/He data from Early Cretaceous volcanic and Precambrian basement samples. We also provide hypotheses on the possible mechanisms able to support the vertical crustal movements of this margin segment, which are also discussed based on some modern rifting models proposed for Central South Atlantic. The central apatite fission-track ages range from 120.6?±?8.9 to 272.9?±?21.6 Ma, with the mean track lengths of approximately 12 µm. The single-grain apatite (U-Th)/He ages vary between 52.2?±?1 and 177.2?±?2.6 Ma. The integration of the thermochronological data set with published geological constraints supports the following time-temperature evolution: (1) heating since the Carboniferous-Permian, (2) cooling onset in the Early Jurassic, (3) heating onset in the Early Cretaceous, (4) cooling onset in the Mid- to Late Cretaceous, (5) heating onset in the Late Cretaceous, and (6) cooling onset in the Oligocene-Miocene. The thermochronological data and the geological constraints, support that the proximal domain of the southwestern Angolan margin was covered in the past by pre-, syn-, and post-rift sediments, which were eroded during succeeding exhumation events. For this margin segment, we show that a development based on long-term denudation is less realistic than one based on burial and exhumation episodes during the last 130 Myr.
DS2000-0197
2000
Da Silva, C.R.S.Da Silva, C.R.S., Wentzcovitch, Patel, Price, KaratoThe composition and geotherm of the lower mantle: constraints from eleasticity of silicate perovskite.Physical Earth and Planetary Interiors, Vol. 118, No.1-2, pp. 103-9.MantleGeothermometry
DS1993-0310
1993
Da Silva, F.C.A.Da Silva, F.C.A., Chauvet, A., Faure, M.Early-Proterzoic Orogeny (Transamazonian) and syntectonic granite emplacement in the Rio Itapicuru greenstone belt, Bahia-BrasilComptes Rendus Academy Science Paris, Tomb. 316, Series II, pp. 1139-1146BrazilGreenstone belt, Tectonics
DS200912-0687
2009
Da Silva, F.P.Sgarbi, G.B.C., Karfunkel, J., De Albuquerque Sgarbi, P.B., Peregovich, B., Da Silva, F.P., Dias, S., MooreThe Paredao kimberlite, western Minas Gerais, Brazil: field relations, chemical dat a and host rocks.Neues Jahrbuch fur Geologie und Palaontologie , Vol. 253, 1, July, pp. 115-131/South America, BrazilDeposit - Paredao
DS1997-0057
1997
Da Silva, L.C.Babinski, M., Chemale, Jr. F., Da Silva, L.C.uranium-lead (U-Pb) and Sm neodymium geochronology of the Neoproterozoic granitic gneissic DomFeliciano BeltJournal of South American Earth Sciences, Vol. 10, No. 3-4, pp. 263-274BrazilGeochronology
DS201412-0121
2014
Da Silva, M.C.R.Chaves, M.L.S.C., Da Silva, M.C.R.Dados disponiveirs sobre a geochronologia dos depositos diamantiferos Proterzoicos da provincia Serra do Espinhacao, MG-BA).6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 2p. AbstractSouth America, Brazil, Minas GeraisEspinhacao area
DS201412-0158
2014
Da Silva, M.C.R.Da Silva, M.C.R., Chaves, M.L.S.C., Andrade, K.W.Sistemas deposicionais tratos de sistemas e a mineralizacao em diamantes da formacao Sopa-Brumadinho na regiiao de Diamantin a ( MG).6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractSouth America, Brazil, Minas GeraisDeposit - Diamantina
DS1991-1876
1991
da Silva, N.B.Williamson, P.A., da Silva, N.B., Vallee, P., Robey, J.V.The Moana-Tinguins melilitite province, Piaui state, northweasternProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 460-462BrazilTectonics, Mineral chemistry
DS2000-0392
2000
Da Silva, Remus et al.Hartmann, L.A., Leite, J.A.D., Da Silva, Remus et al.Advances in SHRIMP geochronology and their impact on understanding tectonic and metallogenic evolution....Australian Journal of Earth Sciences, Vol. 47, No. 5, Oct. pp. 829-44.BrazilGeochronology, Metallogeny
DS201509-0426
2015
Da Silva Amaral, W.Saraiva dos Santos, T.J., Da Silva Amaral, W., Ancelmi, M.F., Pitarello, M.Z., Fuck, R.A., Dantas, E.L.U-Pb age of coesite bearing eclogite from NW Borborema Province, NE Brazil: implications for western Gondwana assembly.Gondwana Research, Vol. 28, pp. 1183-1196.South America, BrazilUHP

Abstract: The Late Neoproterozoic assembly of western Gondwana played an important role in the subduction of oceanic and continental lithospheres. Such event was also a source of arc magmatism, reworking of cratonic margins and development of ultra-high pressure (UHP) suture zones. In the Borborema province, NE Brazil, we have described for the first time UHP rocks enclosed within gneiss migmatite and calc-silicate rocks. They bear coesite included in atoll-type garnet from metamafic rocks, identified by petrographic study and Raman microspectroscopy analysis. U-Pb zircon dating of the leucosome of the migmatites and the calc-silicate rock displays, concordant ages of 639 ± 10 Ma and 649.7 ± 5 Ma, respectively, here interpreted as the minimum age of the eclogitization event in the region. U-Pb zircon dating of the coesite-bearing rock defined a concordia age of 614. 9 ± 7.9 Ma that comprised the retrograde eclogitic conditions to amphibolite facies. The UHP rocks, mostly retrograded to garnet amphibolites, occur enclosed in the Paleoproterozoic continental block composed of calc-silicate rocks, migmatized sillimanite gneiss, mylonitic augen gneiss and granitic and tonalitic gneiss along a narrow N-S oriented belt between the Santa Quitéria magmatic arc and the Transbrasiliano lineament. This block was involved in the subduction to UHP eclogite depths, and was retrogressed to amphibolite during its exhumation and thrusting. Our data indicate an important Neoproterozoic transcontinental suture zone connecting the Pharusian belt with Borborema Province, and probably with the Brasília belt in central Brazil.
DS201901-0022
2018
Da Silva Dias, M.A.F.Cordani, U.G., Ernesto, M., Da Silva Dias, M.A.F., de Alkmim, F.F., Medonca, C.A., Albrecht, R.Un pouco de historia: as Ciencias da Terra no Brasil colonial e no Imperio. ( IN PORT) History of Brazil gold and diamondsEstudos Avancados ( Ensino de Geosciencias na universidade), Vol. 32, (94), pp. 309-330. pdf available in PORT.South America, Brazilhistory
DS2000-0706
2000
da Silva FilhoNeves, S.P., Mariano, G., Guimares, da Silva Filho, MeloIntralithospheric differentiation and crustal growth: evidence from Bororema province, northeastern BrasilGeology, Vol. 28, No. 6, June pp. 519-22.BrazilAlkaline rocks, Geochemistry, Proterozoic crustal growth
DS1998-0290
1998
da Silva Filho, A.Da Pinho Guimardes, I., da Silva Filho, A.neodymium-Strontium isotopic and uranium-lead (U-Pb) geochronologic constraints for evolution of the shoshonitic Brasiliano Bom Jardim ..International Geological Review, Vol. 40, No. 6, June pp. 500-527BrazilAlkaline rocks, Transamazonian mantle, geochronology, Bom Jardim, Toritama
DS1993-0309
1993
Da Silva Filho, A.F.Da Silva Filho, A.F., Guimaraes, I.P., Thompson, R.N.Shoshonitic and ultrapotassic Proterozoic intrusive suites in the Cachoeirinha-Saigueiro belt, northeast Brasil: a transition collisional to post-collisional magmatismPrecambrian Research, Vol. 62, No. 3, June pp. 323-342BrazilShoshonites, Ultrapotassic rocks
DS1997-0235
1997
Da Silva Filho, A.F.Da Silva Filho, A.F., Guimaraes, I.P., Pimentel, M.M.Geochemical signatures of main Neoproterozoic late tectonic granitoids from Proterozoic Sergipano beltInternational Geol. Rev, Vol. 39, No. 7, July, pp. 639-659BrazilGeochemistry - Sergipano, Brasiliano Orogeny
DS1998-0324
1998
da Silva Filho, A.F.De Pinho, I., da Silva Filho, A.F.neodymium and Strontium isotopic and uranium-lead (U-Pb) geochronologic constraints for evolution of the shoshonitic Brasiliana Bom JardiM.International Geology Review, Vol. 40, No. 6, June pp. 500-527.Brazil, BorboremaTectonics, geochronology, Transamazonia enriched mantle
DS201112-0232
2011
Da Silva Filio, A.F.Da Silva Filio, A.F., Guimaraes, I.P., Armstrong, R.A.SHRIMP U Pb geochronology of Neoproterzoic Rio Una sequence, NE Brazil and the Rodinia break-up.Goldschmidt Conference 2011, abstract p.724.South America, Brazil, AfricaGondwana - Borborema Province
DS200412-0394
2004
Da Silva Schmitt, R.Da Silva Schmitt, R., Trouw, R.A.J., Van Schmus, W.R., Pimentel, M.M.Late amalgamation in the central part of West Gondwana: new geochronological dat a and the characterization of a Cambrian collisiPrecambrian Research, Vol. 133, 1-2, August 5, pp. 29-61.South America, BrazilGeochronology, metamorphism
DS201610-1894
2016
da Silva Schmitt, R. .Passchier, C., Trouw, R., da Silva Schmitt, R. .How to make a transverse triple junction - new evidence for the assemblage of Gondwana along the Kaoko-Damara belts, Namibia.Geology, Vol. 44, 10, pp. 843-846.Africa, NamibiaMobile belts

Abstract: T-shaped orogenic triple junctions between mobile belts usually form in two unrelated stages by subsequent and oblique continental collisions separated by a significant time span. Besides these "oblique triple junctions", another type, named "transverse triple junctions", may exist. Such junctions are created by a more complex mechanism of partly contemporaneous convergence of three cratons in a restricted time frame, involving strike slip. The Neoproterozoic-Cambrian Kaoko-Damara junction between the Rio de la Plata, Congo, and Kalahari cratons in Namibia is an example of such a transverse orogenic triple junction, formed by at least four subsequent but partly related deformation events. Initial north-south convergence between the Congo and Kalahari cratons was followed by east-west collision of the Rio de la Plata and Congo cratons. Subsequently, the Kalahari and Congo cratons collided, contemporaneous with sinistral strike-slip motion between the Congo and Rio de la Plata cratons and with the intrusion of large granite-syenite plutons, probably associated with slab detachment aided by the strike-slip movement. Other examples of transverse triple junctions may exist in Gondwana. Transcurrent shear zones, some possibly nucleated on transform faults from the pre-collision setting, are essential for the formation of transverse triple junctions.
DS202002-0217
2019
da Silva Souza, V.Santos Santiago, J., da Silva Souza, V., Dantas, E.L., de Oliveira. C.G.Ediacaran emerald mineralization in northeastern Brazil: the case of the Fazenda Bonfim deposit.Brazil Journal of Geology ( www.scielo.br) ENG, 14p. PdfSouth America, Brazildeposit - Fazenda Bonfim

Abstract: The Fazenda Bonfim emerald deposit lies within the Seridó Belt. It is a classic example of deposit formed through metasomatic interactions between Be-rich granite intrusions and Cr(± V)-rich mafic-ultramafic rocks. The setting of the emerald mineralization was built under strong strike-slip dynamics, which produced serpentinization and talcification of mafic-ultramafic host-rocks, and was followed by syn-kinematic emplacement of Be-rich albite granite, favoring hydrothermal/metasomatic processes. The structural control and lithological-contrast were fundamental to the fluid flow and the best ore-shoot geometry, developed in the S-foliation intra-plane at the contact zone (phlogopite hornfels) between mafic-ultramafic rocks and the albite granite. Subsequently, an albitization process, linked to the final-stage of magmatic crystallization, led to an overall mineralogical and chemical change of the albite granite. 207U-235Pb data revealed inheritance ages from Archean to Neoproterozoic and a crystallization age of 561 ± 4 Ma for albite granite. However, 40Ar/39Ar data revealed plateau age of 553 ± 4 Ma for phlogopite hornfels, interpreted as the closure time for the metasomatic event responsible for the nucleation and growth of emerald crystals. The short interval of time between U-Pb and Ar-Ar data indicates an intense, but not protracted, metasomatic history, probably due to low volume of intrusive magma.
DS200912-0142
2009
Da Silva Valerio, C.Da Silva Valerio, C., da Silva Valerio, V., Macmbira, M.J.B.The 1.90-1.88 Ga magnetism in the southernmost Guyana Shield, Amazonas, Brazil: geology, geochemistry, zircon geochronology and tectonic implications.Journal of South American Earth Sciences, Vol. 28, 3, pp. 304-320.South America, BrazilGeochronology
DS200912-0142
2009
da Silva Valerio, V.Da Silva Valerio, C., da Silva Valerio, V., Macmbira, M.J.B.The 1.90-1.88 Ga magnetism in the southernmost Guyana Shield, Amazonas, Brazil: geology, geochemistry, zircon geochronology and tectonic implications.Journal of South American Earth Sciences, Vol. 28, 3, pp. 304-320.South America, BrazilGeochronology
DS201212-0519
2011
Da Silvira, P.Nez-Valdez, M., Da Silvira, P., Wentzvovitch, R.M.Influence of iron on the elastoc properties of wadsleyite and ringwoodite.Journal of Geophysical Research, Vol. 116, B12, B12112MantleMineralogy
DS1995-0377
1995
Da ZhouDa ZhouWedge extrusion model for the reconstruction of Early Paleozoic tectonics of North Chin a Block. Tarim-QuaidaM.Eos, Abstracts, Vol. 76, No. 17, Apr 25, p. S 283.ChinaEclogite, Tectonics
DS1992-0322
1992
Daala Salda, L.Daala Salda, L., Cingolani, C., Varela, R.Early Paleozoic orogenic belt of the Andes in southwestern South America:results of Laurentia-Gondwana collision?Geology, Vol. 20, No. 7, July pp. 617-620South AmericaTectonics, Plate tectonics
DS1996-0319
1996
Dabler, R.Dabler, R., Yuen, D.A.The metastable olivine wedge in fast subducting slabs: constraints from thermo-kinetic coupling.Earth and Planetary Science Letters, Vol. 137, No. 1/4, Jan. 1, pp. 109-118.MantleGeodynamics, Subduction, plumes
DS2002-0345
2002
Dachs, E.Dachs, E., Proyer, D.Constraints on the duration of high pressure metamorphism in the Tauarn Window from diffusion modelling of discontinuous zones in eclogite garnet.Journal of Metamorphic Geology, Vol. 20, 8, pp. 769-80.GlobalUHP - eclogite
DS200412-0395
2004
Dachs, E.Dachs, E.Petrological elementary tools for Mathematica (R): an update.Computers & Geosciences, Vol. 30, 2, pp. 173-182.TechnologyPetrology - program
DS200412-1597
2004
Dachs, E.Proyer, A., Dachs, E., McCamon, C.pit falls in geothermobarometry of eclogites: Fe 3+ and changes in the mineral chemistry of omphacite at ultrahigh pressures.Contributions to Mineralogy and Petrology, Vol. 147, 3, pp. 305-329.TechnologyEclogite - geochemistry
DS200812-0710
2008
Dachs, E.Manon, M.R., Dachs, E., Essene, E.J.Low T heat capacity measurements and new entropy dat a for titanite ( sphene) implications for thermobarometry of high pressure rocks.Contributions to Mineralogy and Petrology, Vol. 156, 6, pp. 709-720.TechnologyUHP
DS1992-1618
1992
Dackombe, R.V.Walden, J., Smith, J.P., Dackombe, R.V.The use of simultaneous R and Q mode factor analysis as a tool for assisting interpretation of mineral magnetic dataMath. Geol, Vol. 24, No. 3, pp. 227-247GlobalPaleomagnetism, Factor analysis
DS2003-0305
2003
D'Acremont, E.D'Acremont, E., Leroy, S., Burov, E.B.Numerical modelling of a mantle plume: the plume head lithosphere interaction in theEarth and Planetary Science Letters, Vol. 206, No. 3-4, pp. 379-396.MantleModel - plume
DS1920-0279
1926
Dacy, G.H.Dacy, G.H.America's Infant Diamond IndustryCompressed Air Magazine, Vol. 31, MARCH PP. 1553-1555.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS201412-0927
2014
Daczko, N.R.Tetley, M.G., Daczko, N.R.Virtual petrographic microscope: a multi-platform education and research software tool to analyze rock thin-sections.Australian Journal of Earth Sciences, Vol. 61, 4, pp. 631-637.TechnologyPetrography
DS1998-0291
1998
Dade, W.B.Dade, W.B., Friend, P.F.Grain size, sediment transport regime, and Channel slope in alluvialrivers.Journal of Geology, Vol. 106, No.6, Nov. pp. 661-76.GlobalAlluvials, River - drainage - not specific to diamonds
DS1988-0152
1988
Daelman, P.A.Daelman, P.A.A base for grading naturally coloured diamondsCanadian Gemologist, Vol. IX, No. 4, pp. 102-103GlobalDiamond grading, Natural diamond
DS1989-0321
1989
Dagbert, M.Dagbert, M., Buchanan, M.J., Duplessis, C.Evaluating industrial minerals deposits- Microcomputers can helpThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Annual Meeting Preprint, Outline of slide comments only, 8p. Database # 18040GlobalComputer, Program -slide comments only
DS1989-0322
1989
Dagbert, M.Dagbert, M., de l'Etolie, R., McLean, P., Lane, A.SECTCAD: un programme de C.A.O. pour l'evaluation desgisements.*FRENCHThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Annual Meeting Preprint and Outline of slides *FRENCH, 22p. Database # 18041GlobalComputer, Program -SECTCAD.
DS1990-0382
1990
Dagbert, M.Dagbert, M.Nested indicator approach for ore reserve estimation in highly variablemineralizationThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Annual Meeting Paper preprint, No. 101, 11pGlobalGeostatistics, Ore reserves -indicator kriging
DS201412-0159
2014
Dagbert, M.Dagbert, M.Review of book Mineral Resource estimation by Mario Rossi and Clayton Deutsch. 3320. Mathematical Geosciences, Vol. 46, 8, pp. 1029-1034.TechnologyBook: review
DS1994-0362
1994
Dagdelen, K.Dagdelen, K.Estimating recoverable reserves: developments in geostatistical ore reserveestimationAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Meeting held Albuquerque Feb. 14-17th, No. 94-239, 9pGlobalGeostatistics, Ore reserves
DS1996-0320
1996
Dagdelen, K.Dagdelen, K.Mining dilution in geostatistical ore reserve estimationSociety for Mining, Metallurgy and Exploration (SME)-American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, 96-201GlobalGeostatistics, Ore reserves
DS1994-1499
1994
Dagelaiskii, V.V.Rundquist, D.V., Dagelaiskii, V.V., Khiltova, V.Ya.Zoning and evolutionary rows of the Precambrian ore-bearing structuresGeology of Ore Deposits, Vol. 36, No. 5, pp. 351-361GlobalMetallogeny, zoning, Precambrian
DS1990-0383
1990
Dagger, G.W.Dagger, G.W.Optical mineralogy using SIMPLISComputers and Geosciences, Vol. 16, No. 1, pp. 111-135GlobalProgram -SIMPLIS Mineralogy, Computer
DS200412-0396
2004
D'Agreela Filho, M.S.D'Agreela Filho, M.S., Pacca, II., Trinidade, R.I., Teixeira, W., Raposo, M.I., Onstott, T.C.Paleomagnetism and 40 Ar 39 Ar ages of mafic dikes from Salvador ( Brazil): new constraints on the Sao Francisco craton APW pathPrecambrian Research, Vol. 132, 1-2, pp. 55-77.South America, BrazilGeochronology
DS1994-0363
1994
D'Agrella Filho, M.S.D'Agrella Filho, M.S., Pacca, I.I.G.Tectonic implications for the development of late Proterozoic Pan-African and Brasiliano mobile belts.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 88-90.BrazilTectonics, Proterozoic paleomagnetics, Sa Francisco craton
DS1998-0292
1998
D'Agrella Filho, M.S.D'Agrella Filho, M.S., Pacca, I.I.G.Paleomagnetism of a Paleoproterozoic mafic dyke swarm from the Uauaregion..Journal of South American Earth Sciences, Vol. 11, No. 1, pp. 23-34BrazilSao Francisco Craton, Tectonics
DS1999-0731
1999
D'Agrella Filho, M.S.Teixeira, W., Renne, P.R., D'Agrella Filho, M.S.40 Ar-39 Ar and Rubidium-Strontium geochronology of the Urugurayan dike swarm, Rio de la Plat a Craton.... Proterozoic...Precambrian Research, Vol. 92, No. 2-3, Jan. 31, pp. 153-180.UruguayGeochronology, dike swarm, Argon, Rubidium, Tectonics - Gondwana
DS2003-0281
2003
D'Agrella Filho, M.S.Cordiani, U.G., D'Agrella Filho, M.S., Brito Neves, B.B., Trindada, R.I.Tearing up Rodinia: the Neoproterozoic paleogeorgraphy of South American cratonicTerra Nova, Vol. 15, 5, pp. 350-359.South America, Rodinia, GondwanaTectonics, craton
DS200412-0364
2003
D'Agrella Filho, M.S.Cordiani, U.G., D'Agrella Filho, M.S., Brito Neves, B.B., Trindada, R.I.Tearing up Rodinia: the Neoproterozoic paleogeorgraphy of South American cratonic fragments.Terra Nova, Vol. 15, 5, pp. 350-359.South America, Rodinia, GondwanaTectonics, craton
DS200412-1625
2004
D'Agrella Filho, M.S.Raposo, M.I., Chaves, A.O., Lojkasek Lima, P., D'Agrella Filho, M.S., Teixeira, W.Magnetic fabrics and rock magnetism of Proterozoic dike swarm from the southern Sao Francisco Craton, Minas Gerais, Brazil.Tectonophysics, Vol. 378, 1-2, pp. 43-63.South America, Brazil, Minas GeraisGeophysics - magnetics
DS200612-1430
2006
D'Agrella Filho, M.S.Tohver, E., D'Agrella Filho, M.S., Trindade, R.I.F.Paleomagnetic record of Africa and South America for 1200 - 500 Ma interval, and evaluation of Rodinia and Gondwana assemblies.Precambrian Research, Vol. 147, 3-4, July 5, pp. 193-222.Africa, South AmericaGeochronology
DS200712-0874
2007
D'Agrella Filho, M.S.Raposo, M.I., D'Agrella Filho, M.S., Pinese, J.P.Magnetic fabrics and rock magnetism of Archean and Proterozoic dike swarms in the Sao Francisco craton, Brazil.Tectonophysics, Vol. 443, 1-2, pp. 53-71.South America, BrazilDike Swarms
DS201606-1084
2016
D'Agrella-FilhoEvans, D.A.D., Trindade, R.I.F., Catelani, E.L., D'Agrella-Filho, Heaman, L.M., Oliveira, E.P., Soderlund, U., Ernst, R.E., Smirnovm A.V., Salminen, J.M.Return to Rodinia? Moderate to high paleolatitude of the Sao Francisco/Congo craton at 920 Ma.Geological Society of London Special Publication Supercontinent Cycles through Earth History., Vol. 424, pp. 167-190.South America, BrazilSupercontinents

Abstract: Moderate to high palaeolatitudes recorded in mafic dykes, exposed along the coast of Bahia, Brazil, are partly responsible for some interpretations that the São Francisco/Congo craton was separate from the low-latitude Rodinia supercontinent at about 1050 Ma. We report new palaeomagnetic data that replicate the previous results. However, we obtain substantially younger U-Pb baddeleyite ages from five dykes previously thought to be 1.02- 1.01 Ga according to the 40 Ar/ 39 Ar method. Specifically, the so-called 'A-normal' remanence direction from Salva-dor is dated at 924.2 + 3.8 Ma, within error of the age for the 'C' remanence direction at 921.5 + 4.3 Ma. An 'A-normal' dyke at Ilhéus is dated at 926.1 + 4.6 Ma, and two 'A-normal' dykes at Olivença have indistinguishable ages with best estimate of emplacement at 918.2 + 6.7 Ma. We attribute the palaeomagnetic variance of the 'A-normal' and 'C' directions to lack of averaging of geomagnetic palaeosecular variation in some regions. Our results render previous 40 Ar/ 39 Ar ages from the dykes suspect, leaving late Mesoproterozoic palaeolatitudes of the São Francisco/Congo craton unconstrained. The combined 'A-normal' palaeomagnetic pole from coastal Bahia places the São Francisco/Congo craton in moderate to high palaeolatitudes at c. 920 Ma, allowing various possible positions of that block within Rodinia. Despite more than two decades of intense global research, the configuration of Neoproterozoic supercontinent Rodinia remains enigmatic. Following the first global synthesis by Hoffman (1991), most models include a central location for Laurentia, flanked by 'East' Gondwana-Land cra-tons along its proto-Cordilleran margin and 'West'
DS1998-0293
1998
D'Agrella-Filho, M.D'Agrella-Filho, M., et al.Paleomagnetic constraints on the Rodinia supercontinent: implications for its Neoproterozoic ...International Geology Review, Vol. 40, pp. 171-188.GondwanaTectonics, Laurentia, Cong-Sao Francisco, Kalahari, Craton - Amazonia
DS1990-0384
1990
D'Agrella-Filho, M.S.D'Agrella-Filho, M.S., Pacca, I.G., Renne, P.R., Onstott, T.C.Paleomagnetism and middle Proterozoic (1.01 to 1.08 Ga) mafic dykes in southeastern Bahia State-Sao Francisco Craton, BrasilEarth and Planetary Science Letters, Vol. 101, No. 2/4, December pp. 332-348BrazilPaleomagnetism, Dykes
DS1990-1221
1990
D'Agrella-Filho, M.S.Renne, P.R., Onstott, T.C., D'Agrella-Filho, M.S., Pacca, I.G.40 Ar-39 Ar dating of 1.0-1.1 Ga magnetizations from the Sao Francisco and Kalahari cratons: tectonic implicationsPan-African and Brasiliano mobilebeltsEarth and Planetary Science Letters, Vol. 101, No. 2/4, December pp. 349-367Brazil, southern AfricaPaleomagnetism, Argon, Craton
DS1998-0294
1998
D'Agrella-Filho, M.S.D'Agrella-Filho, M.S., Trindade, R.I.F., Pacca, I.I.G.Paleomagnetic constraints on Rodinia supercontinent: implications for its Neoproterozoic Break ups- GondwanaInternational.Geol. Rev, Vol. 40, No. 2, Feb. pp. 171-?Gondwana, RodiniaPalemagnetism, Tectonics
DS200612-1431
2006
D'Agrella-Filho, M.S.Tohver, E., D'Agrella-Filho, M.S., Trinidade, R.I.F.Paleomagnetic record of Africa and South America for the 1200 - 500 Ma interval, and evaluation of Rodinia and Gondwana assemblies.Precambrian Research, In press, availableAfrica, South America, Democratic Republic of Congo, Arabia, Nubian ShieldCraton, Kalahari, Sao Francisco, paleomagnetism
DS200612-1438
2006
D'Agrella-Filho, M.S.Trindade, R.I.F., D'Agrella-Filho, M.S., Epof, I., Brito Neves, B.B.Paleomagnetism of Early Cambrian Itabaiana mafic dikes ( NE Brazil) and the final assembly of Gondwana.Earth and Planetary Science Letters, Vol. 244, 1-2, Apr. 15, pp. 361-377.South America, BrazilDike swarms
DS200912-0126
2009
D'Agrella-Filho, M.S.Cordani, U.G., Texiera, W., D'Agrella-Filho, M.S., Trindade, R.I.The position of the Amazonian craton in supercontinents.Gondwana Research, Vol. 15, 3-4, pp. 396-407.Mantle, South AmericaCraton - Amazon
DS200912-0806
2009
D'Agrella-Filho, M.S.Wang, X-C., Li, X-H., D'Agrella-Filho, M.S., Trindade, R.I.Variable involvements of mantle plumes in the genesis of mid-Neoproterozoic basaltic rocks in South China: a review.Gondwana Research, Vol. 15, 3-4, pp. 381-395.ChinaHotspots
DS201812-2796
2017
D'Agrella-Filho, M.S.D'Agrella-Filho, M.S., Cordani, U.G.The paleomagnetic record of the Sao Francisco-Congo craton.Heilbron et al. eds. Sao Francisco Craton, eastern Brazil, Chapter 16, 17p. ResearchgateSouth America, Brazilgeochronology

Abstract: This chapter, based on paleomagnetic and geologic-geochronological evidence, discusses the position of the São Francisco craton and other South American and African cratonic blocks within paleo-continents, since the formation of Columbia supercontinent in the Paleoproterozoic up to the fragmentation of Pangea in the Mesozoic. In Paleoproterozoic times, between ca. 2.0 and 1.8 Ga, two large independent landmasses were formed. The first one involved several cratonic blocks that were leading to the formation of Laurentia. Later, Laurentia, proto-Amazonia, West Africa and Baltica amalgamated to form the nucleus of the supercontinent Columbia at about 1.78 Ga. The second landmass encompassed the São Francisco-Congo, Kalahari, Rio de la Plata and Borborema-Trans-Sahara, forming the Central African block. For the São Francisco-Congo and Kalahari cratons, two robust Paleoproterozoic poles are available. One is from the Jequié charnockites of Bahia (São Francisco Craton), and the other from the Limpopo high-grade metamorphics in South Africa (Kalahari Craton). They support the possible link between these two cratonic blocks at ca. 2.0 Ga. Columbia may have remained united until 1.25 Ga, when Baltica and Amazonia/West Africa broke apart. Their paleomagnetic record seems to indicate that both executed clockwise rotations, until they collided with Laurentia along the Grenville belt at ca. 1.0 Ga., culminating with the formation of Rodinia. For the Central African block, however, there are no reliable paleomagnetic poles available between 1.78 and 1.27 MA. Nevertheless, during this time interval, the geological-geochronological evidence indicates that no continental collisional episodes affected the São Francisco-Congo craton, where important intra-plate tectonic episodes occurred. Most probably, this large continental block drifted alone since the end of the Paleoproterozoic and did not take part of Columbia or Rodinia. At the end of the Mesoproterozoic, ca. 1100 MA, the robust Umkondo pole of the Kalahari craton, as part of the Central African block, and the equally robust Keweenawan pole of Laurentia at the center of Rodinia, indicated that these landmasses were very far apart. At that time a large oceanic realm, the Goiás-Pharusian Ocean, was indeed separating Amazonia-West Africa from the Central African block. This ocean closed by a continued subduction process that started at ca. 900 MA and ended in a collisional belt with Himalayan-type mountains at ca. 615 MA, as part of the few continental collisions which formed Gondwana. However, the age of the final convergence is still a matter of debate, because paleomagnetic measurements for the Araras Group, which occurs within the Paraguay belt at the eastern margin of the Amazonian craton, would indicate that a large ocean was still in existence between it and São Francisco craton close to the Ediacaran/Cambrian boundary. Consensus about this matter awaits for further paleomagnetic data. Gondwana collided with Laurasia during the late Paleozoic, at about 300 Ma, originating Pangea, which not much later started splitting apart, near the Permian/Triassic boundary. As part of this present-time plate tectonic regime, the São Francisco Craton (in South America) started separation from the Congo craton (in Africa) in Jurassic times, giving rise of the present-day oceanic lithosphere of the Atlantic Ocean.
DS202010-1835
2020
D'Agrella-Filho, M.S.D'Agrella-Filho, M.S., Paul, Y.J., Antonio, P.Y.J., Bispo-Santos, F.The Precambrian drift history and paleogeography of Amazonia.Chapter 6,, Personen et al. ed. Precambrian Supercontinents, 99p. PdfSouth Americacraton

Abstract: Here, we reassess the paleomagnetic database for Amazonia and its geodynamic implications for supercontinents. According to paleomagnetic and geological data, Amazonia and West Africa joined at ca. 2.00 Ga defining a single long-lived block. This landmass eventually formed a part of the Columbia supercontinent together with Baltica and Laurentia between 1.78 and 1.42 Ga. For the formation of Rodinia paleomagnetic and geological data permit three different models: an oblique collision at ca. 1.2 Ga, a clockwise rotation of Amazonia/West Africa and Baltica from Columbia to Rodinia joining Laurentia at ca. 1.0 Ga, or a scenario where Amazonia/West Africa was a wandering block that did not take part in Columbia and collided with Laurentia to form Rodinia at ca. 1.0-0.95 Ga. The time Amazonia/West Africa joined Gondwana is also debatable, with contrasting geochronological and geological evidence supporting an early collision at 0.65-0.60 Ga or a late collision at 0.53-0.52 Ga.
DS201012-0134
2010
Dagupta, R.Dagupta, R., Hirschmann, M.M.The deep carbon cycle and melting in Earth's interior.Earth and Planetary Science Letters, Vol. 298, 1-2, Sept. 15, pp. 1-13.MantleMelting
DS202002-0180
2020
Dagupta, R.Eguchi, J., Seales, J., Dagupta, R.Great oxidation and Lomagundi events linked by deep cycling and enhanced degassing of carbon.Nature Geoscience, Vol. 13, pp. 71-76. Mantlecarbon

Abstract: For approximately the first 2?billion years of the Earth’s history, atmospheric oxygen levels were extremely low. It was not until at least half a billion years after the evolution of oxygenic photosynthesis, perhaps as early as 3?billion years ago, that oxygen rose to appreciable levels during the Great Oxidation Event. Shortly after, marine carbonates underwent a large positive spike in carbon isotope ratios known as the Lomagundi event. The mechanisms responsible for the Great Oxidation and Lomagundi events remain debated. Using a carbon-oxygen box model that tracks the Earth’s surface and interior carbon fluxes and reservoirs, while also tracking carbon isotopes and atmospheric oxygen levels, we demonstrate that about 2.5?billion years ago a tectonic transition that resulted in increased volcanic CO2 emissions could have led to increased deposition of both carbonates and organic carbon (organic?C)?via enhanced weathering and nutrient delivery to oceans. Increased burial of carbonates and organic?C would have allowed the accumulation of atmospheric oxygen while also increasing the delivery of carbon to subduction zones. Coupled with preferential release of carbonates at arc volcanoes and deep recycling of organic?C to ocean island volcanoes, we find that such a tectonic transition can simultaneously explain the Great Oxidation and Lomagundi events without any change in the fraction of carbon buried as organic?C relative to carbonate, which is often invoked to explain carbon isotope excursions.
DS1996-0321
1996
Dahl, G.L.Dahl, G.L., Emmett, J.L.Montana sapphires: swans from ugly duckling.Mineral Industry International., No. April, pp.MontanaLaboratory treatment -heat, Sapphires
DS2003-0306
2003
Dahl, J.E.P.Dahl, J.E.P., Moldowan, J.M.Diamond in the rough.. collection of diamondlike compounds in oilScience News, Vol. 163, No. 20, May 17, p. 310.GlobalTechnology
DS2003-0307
2003
Dahl, J.E.P.Dahl, J.E.P., Moldowan, J.M., Peakman, T.M., Clardy, J.C., Lobkovsky, E.Isolation and structural proof of the large diamond molecule, cycloheamantane (Angewandte Chemie, Vol. 42, 18, pp. 2040-44.GlobalMineral chemistry
DS200412-0397
2003
Dahl, J.E.P.Dahl, J.E.P., Moldowan, J.M.Diamond in the rough.. collection of diamondlike compounds in oil.Science News, Vol. 163, no. 20, May 17, p. 310.TechnologyTechnology
DS200412-0398
2003
Dahl, J.E.P.Dahl, J.E.P., Moldowan, J.M., Peakman, T.M., Clardy, J.C., Lobkovsky, E., Olmstead, M.M., May, P.W., Davis, T.Isolation and structural proof of the large diamond molecule, cycloheamantane ( C26H30).Angewandte Chemie, Vol. 42, 18, pp. 2040-44.TechnologyMineral chemistry
DS201706-1082
2017
Dahl, P.Hrncir, J., Karlestrom, K., Dahl, P.Wyoming on the run - toward final Paleoproterozoic assembly of Laurentia. Geology Forum Comment, April 1p.United Statescraton

Abstract: Paleoproterozoic suture zones mark the formation of supercontinent Nuna and provide a record of North America's assembly. Conspicuously young ages (ca. 1.715 Ga) associated with deformation in southeast Wyoming craton argue for a more protracted consolidation of Laurentia, long after peak metamorphism in the Trans-Hudson orogen. Using paleomagnetic data from the newly dated 1899 ± 5 Ma Sourdough mafic dike swarm (Wyoming craton), we compare the relative positions of Wyoming, Superior, and Slave cratons before, during, and after peak metamorphism in the Trans-Hudson orogen. With these constraints, we refine a collisional model for Laurentia that incorporates Wyoming craton after Superior and Slave cratons united, redefining the Paleoproterozoic sutures that bind southern Laurentia.
DS1990-0385
1990
Dahl, P.S.Dahl, P.S.A PC and LOTUS based dat a acquisition reduction system for an ICPspectrometerComputers and Geosciences, Vol. 16, No. 7, pp. 881-896GlobalComputer, Program -ICP Spectrometer
DS1995-0906
1995
Dahl, P.S.Kamber, B.S., Blenkinsop, T.G., Villa, I.M., Dahl, P.S.Proterozoic transpressive deformation in the northern marginal zone, Limpopo Belt, ZimbabweJournal of Geology, Vol. 103, No. 5, Sept. pp. 493-508ZimbabweTectonics,, Limpopo Belt
DS1997-0516
1997
Dahl, P.S.Holm, D.K., Dahl, P.S.40Ar 39Ar evidence for Middle Proterozoic (1300-1500 Ma) slow cooling of southern Black Hills, midcontinentTectonics, Vol. 16, No. 4, August pp. 609-622.GlobalMagmatism, Tectonics
DS1998-0295
1998
Dahl, P.S.Dahl, P.S.When did the Wyoming Province collide with Laurentia? New clues fromstep-leach lead lead dating of garnet...Geological Society of America (GSA) Annual Meeting, abstract. only, p.A109.WyomingTectonic, Craton
DS2002-0346
2002
Dahl, P.S.Dahl, P.S., Hamilton, M.A.Ion microprobe evidence for early Proterozoic thermotectonics reworking of the NW Archean Wyoming...Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.25., p.25.MontanaGreat Falls Tectonic Zone, Tectonics
DS2002-0347
2002
Dahl, P.S.Dahl, P.S., Hamilton, M.A.Ion microprobe evidence for early Proterozoic thermotectonics reworking of the NW Archean Wyoming...Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.25., p.25.MontanaGreat Falls Tectonic Zone, Tectonics
DS200512-0201
2004
Dahl, P.S.Dahl, P.S., Hamilton, M.A., Wooden, J.L., Tracy, R.J., Loehn, C.W., Jones, C.L., Foland, K.A.Do 2450-2480 mineral ages from Wyoming cratonic margins (USA) indicate incipient breakup of supercontinet Kenorland?Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 142-8, Vol. 36, 5, p. 340.United States, WyomingGeochronology
DS200712-0212
2007
Dahl, P.S.Dahl, P.S., Hamilton, M.A., Wooden, J.L., Foland, K.A., Frei, R., McCombc, J.A., Holm, D.K.2480 Ma mafic magmatism in the northern Black Hills, South Dakota: a new link connecting the Wyoming and Superior Cratons.Canadian Journal of Earth Sciences, Vol. 43, 10, pp. 1579-1600.United States, Wyoming, Canada, AlbertaMagmatism
DS1991-1250
1991
Dahl, R.Ohenstetter, D., Watkinson, D.H., Dahl, R.Zoned hollingworthite from Two Duck Lake intrusion, Coldwell Complex, Ontario.American Mineralogist, Vol. 76, pp. 1694-1700.OntarioColdwell alkaline complex area
DS201606-1081
2016
Dahl, T.W.Dahl, T.W.Identifiying remnants of early Earth.Science, Vol. 352, 6287, May 13, pp. 768-769.MantleDynamics - convection

Abstract: The chemical composition of Earth's mantle can tell us how our planet formed and how subsequent mantle dynamics have since homogenized the mantle through convective processes. Most terrestrial rocks have a similar tungsten (W) isotope composition (1), but some rocks that have been dated at 2.8 Ga (billion years old) (2), 3.8 Ga (3), and 3.96 Ga (4) have elevated 182W/184W ratios. This is reported as µ182W, in parts per million (ppm) deviation from the bulk silicate Earth. Until now, the outliers have included only these ancient rock samples with a small µ182W excess (=15 ppm) that can be attributed to the final ~0.5% of Earth's mass that accreted late in its accretion history. On page 809 of this issue, Rizo et al. (5) report W isotope data from young mantle-derived rocks with µ182W excesses of 10 to 48 ppm. This result is spectacular because the range of µ182W values in mantle-derived rocks is larger than can be accommodated by late accretion; the implication is that remnants of Earth's earliest mantle have been preserved over the entirety of Earth's history.
DS200412-0406
2004
Dahl Jensen, T.Darbyshire, F.A., Larsen, T.B., Mosegaard, K., Dahl Jensen, T., Gudmundsson, O., Bach, T., Gregersen, S., PedeA first detailed look at the Greenland lithosphere and upper mantle; using Rayleigh wave tomography.Geophysical Journal International, Vol. 158, 1, pp. 267-286.Europe, GreenlandGeophysics - seismic
DS2002-1347
2002
Dahl. P.Roberts, H., Dahl. P., Kelley, S., Frei, R.New 207 Pb 206 Pb and 40 Ar 39 Ar ages from SW Montana: constraints on the Proterozoic and Archean tectonic and depositional history of the Wyoming Province.Tectonophysics, Vol.352,1-2,July, pp. 119-143.MontanaGeochronology
DS1960-0679
1966
Dahlem, D.H.Heinrich, .W., Dahlem, D.H.Carbonatites and Alkalic Rocks of the Arkansaw River Area, Fremont county, Colorado.Mineralogical Society of India 4TH. VOLUME., PP. 37-44.United States, Colorado PlateauBlank
DS1960-0840
1967
Dahlem, D.H.Heinrich, E.W., Dahlem, D.H.Carbonatites and Alkalic Rocks of the Arkansaw River Area, Fremont county, Colorado. Part 4. the Pinon Peak Breccia Pipes.American Mineralogist., Vol. 52, No. 5-6, PP. 817-831.United States, Colorado, Rocky MountainsDiatreme
DS1992-0323
1992
Dahlen, F.A.Dahlen, F.A.Metamorphism of nonhydrostatically stressed rocksAmerican Journal of Science, Vol. 292, No. 3, March pp. 184-198Globalmetamorphism
DS200412-1355
2004
Dahlen, F.A.Montelli, R., Nolet, G., Dahlen, F.A., Masters, G., Engdahl, E.R., Hung, S.H.Finite frequency tomography reveals a variety of plumes in the mantle.Science, No. 5656 Jan. 16, pp. 338-42.MantleGeophysics - seismics
DS200612-1616
2006
Dahlen, F.A.Zhou, Y., Nolet, G., Dahlen, F.A., Laske, G.Global upper mantle structure from finite frequency surface wave tomography.Journal of Geophysical Research, Vol. 111, B4 B04304 2005JB003677MantleTomography
DS200612-1617
2006
Dahlen, F.A.Zhou, Y., Nolet, G., Dahlen, F.A., Laske, G.Global upper mantle structure from finite frequency surface wave tomography.Journal of Geophysical Research, Vol. 111, B4, B04304.MantleGeophysics - seismics
DS200712-0744
2006
Dahlen, F.A.Montelli, R., Nolet, G., Dahlen, F.A., Masters, G.A catalogue of deep mantle plumes: new results from finite-frequency tomography.Geochemical, Geophysics, Geosystems: G3, Vol. 7 Q11007Global, mantleGeophysics - seismics, Frechet derivatives
DS201807-1498
2018
Dahlgren, R.A.Houlton, B.Z., Morford, S.L., Dahlgren, R.A.Convergent evidence for Wide spread rock nitrogen sources in Earth's surface environment.Science, Vol. 360, pp. 58-62.Mantlenitrogen

Abstract: Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth’s land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet’s nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth’s nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink.
DS1994-0066
1994
Dahlgren, S.Arzamastev, A.A., Dahlgren, S.Plutonic mineral assemblages in dikes and explosion pipes in Paleozoic alkaline province of Baltic Shield.Geochemistry International, Vol. 31, No. 3, pp. 57-68.Baltic Shield, KolaAlkaline rocks, Diatremes
DS1994-0364
1994
Dahlgren, S.Dahlgren, S.Late Proterozoic and Carboniferous ultramafic magmatism of carbonatitic affinity in southern Norway.Lithos, Vol. 31, No. 3/4, January pp. 141-154.NorwayCarbonatite
DS1999-0468
1999
Dahlgren, S.Meert, J.G., Torsvik, T.H., Eide, E.A., Dahlgren, S.Tectonic significance of the Fen Province: constraints from geochronology and PaleomagnetismJournal of Geology, Vol. 106, No. 5, Sept. pp. 553-64.NorwayTectonics, Dikes
DS201802-0233
2018
Dahlgren, S.Elliott, H.A.L., Wall, F., Chakmouradian, A.R., Siegfried, P.R., Dahlgren, S., Weatherley, S., Finch, A.A., Marks, M.A.W., Dowman, E., Deady, E.Fenites associated with carbonatite complexes: a review.Ore Geology Reviews, Vol. 92, pp. 38-59.Globalcarbonatites

Abstract: Carbonatites and alkaline-silicate rocks are the most important sources of rare earth elements (REE) and niobium (Nb), both of which are metals imperative to technological advancement and associated with high risks of supply interruption. Cooling and crystallizing carbonatitic and alkaline melts expel multiple pulses of alkali-rich aqueous fluids which metasomatize the surrounding country rocks, forming fenites during a process called fenitization. These alkalis and volatiles are original constituents of the magma that are not recorded in the carbonatite rock, and therefore fenites should not be dismissed during the description of a carbonatite system. This paper reviews the existing literature, focusing on 17 worldwide carbonatite complexes whose attributes are used to discuss the main features and processes of fenitization. Although many attempts have been made in the literature to categorize and name fenites, it is recommended that the IUGS metamorphic nomenclature be used to describe predominant mineralogy and textures. Complexing anions greatly enhance the solubility of REE and Nb in these fenitizing fluids, mobilizing them into the surrounding country rock, and precipitating REE- and Nb-enriched micro-mineral assemblages. As such, fenites have significant potential to be used as an exploration tool to find mineralized intrusions in a similar way alteration patterns are used in other ore systems, such as porphyry copper deposits. Strong trends have been identified between the presence of more complex veining textures, mineralogy and brecciation in fenites with intermediate stage Nb-enriched and later stage REE-enriched magmas. However, compiling this evidence has also highlighted large gaps in the literature relating to fenitization. These need to be addressed before fenite can be used as a comprehensive and effective exploration tool.
DS201906-1285
2019
Dahlgren, S.Coint, N., Dahlgren, S.Assessing the distribution of REE mineralization in Fe-dolomite carbonatite drill cores from the Fen complex, Telemark, southern Norway.GAC/MAC annual Meeting, 1p. Abstract p. 72.Europe, NorwayCarbonatite

Abstract: The Fen Complex is a 2 km-wide subcircular intrusion composed mainly of sovite, Fe-dolomite carbonatite, damtjernite (lamprophyre) and minor alkaline rocks such as nepheline syenite and ijolite, emplaced at 580 Ma through Mesoproterozoic orthogneisses forming the Fennoscandian Shield. Previous bulk-rock isotopic study indicates that the carbonatite magma originated in the upper mantle [(87Sr/86Sr)i = 0.7029] and underwent contamination during its ascent throughout the crust. This study focuses on two deep cores (1000 m and 700 m), drilled to assess the distribution of REE mineralizations in the Fe-dolomite carbonatite. Hyperspectral data, allowing investigators to log cores objectively and quantify lithologies, were acquired using a SisuRock Gen 2 system composed of three cameras gathering data in the following wavelengths: RGB, Near-Visible Short-Wave Infrared (VN-SWIR) and Long-Wave Infrared (LWIR). In addition, every meter of the first core and 500 m of the second one were analyzed for bulk-rock geochemistry to characterize the distribution of elements. In this study, we compare the results obtained by the imaging technique with the bulk-rock data and present preliminary results of the textural variations observed in rare-earth mineralizations. Preliminary results indicate that neither of the deep bore holes reached the fenitized host-rock and that the Fe-dolomite carbonatite continues at depth. In both cores, the dominant carbonate is Fe-rich dolomite, although calcite and Fe-Mg carbonate have been observed locally. REE-minerals, composed mainly of bastnäsite, parisite/synchisite and monazite, display variable textural relationships and often occur together in clusters associated with barite and minor Fe-oxides, sulfides (pyrite ± sphalerite) and locally thorite.
DS1989-0323
1989
Dahlgren, S.H.Dahlgren, S.H.Zoned carbonatite- Damtjernite sheet intrusions in the Fen Province, southern Norway: evidence for magma withdrawal from zoned reservoirsGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A71. (abstract.)NorwayFen, Carbonatite
DS1989-0324
1989
Dahlheim, H.A.Dahlheim, H.A., Davis, P., Achauer, U.Teleseismic investigation of the East African Rift- KenyaJournal of African Earth Sciences, Vol. 8, No. 2/3/4, pp. 461-470KenyaTectonics, Rifting
DS2001-0488
2001
DahlJensen, Reid etc.Hopper, W.S., Larsen, Korenaga, DahlJensen, Reid etc.Mantle thermal structure and active upwelling during continental breakup in the North Atlantic.Earth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 251-66.Baltica, Greenland, NorwayTectonics, Plume
DS1998-0296
1998
Dahl-Jensen, T.Dahl-Jensen, T., Thybo, H., Rosing, M.Crustal structure at the southeast Greenland margin from wide angle and normal incidence seismic data.Tectonophysics, Vol. 288, No. 1-4, Mar. pp. 191-198.GreenlandTectonics, Geophysics - seismic
DS200712-0872
2007
DahlquistRapela, C.W., Pankhurst, R.J., Casquet, C., Fanning, C.M., Baldor Casado, E.G., Galindo, C., DahlquistThe Rio de la Plat a craton and the assembly of SW Gondwana.Earth Science Reviews, In press availableSouth America, BrazilTectonics
DS200712-0873
2007
Dahlquist, J.Rapela, C.W., Pankhurts, R.J., Casquet, C., Fanning, C.M., Baldo, E.G., Gonzalez-Casado, J.M., Galindo, C., Dahlquist, J.The Rio de la Plate craton and the assembly of SW Gondwana.Earth Science Reviews, Vol. 83, 1-2, pp. 49-82.South America, BrazilCraton, tectonics
DS200812-1173
2008
Dahm, T.Tilmann, F.J., Dahm, T.Constraints on crustal and mantle structure of the oceanic plate south of Iceland from ocean bottom recorded Rayleigh waves.Tectonophysics, Vol. 447, 1-4, pp. 66-79.Europe, IcelandTectonics
DS201312-0899
2013
Dahmada, M.E.M.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
DS201112-0965
2011
Dahrouge, J.Simandl, G.J., Fajber, R., Dunn, C.E., Ulry, B., Dahrouge, J.Biogeochemical exploration vectors in search of carbonatite, Blue River British Columbia.British Columbia Geological Survey, BCGS GeoFile, 2011-05.Canada, British ColumbiaCarbonatite
DS1998-0297
1998
Dahroughe, J.R.Dahroughe, J.R.Metallic and industrial mineral assessment report on the Cox ERDA propertyAlberta Geological Survey, MIN 19980025AlbertaExploration - assessment, New Blue Ribbon, New Claymore Resources Ltd.
DS1998-1111
1998
Dahroughe, J.R.Pana, D.I., Dahroughe, J.R.Metallic and industrial mineral assessment report on the diamond exploration on Lesser Slave Lake property.Alberta Geological Survey, MIN 19980008AlbertaExploration - assessment
DS1994-0366
1994
DaiDai, LuluThe mineral chemistry and magma evolution of the Big Spruce Lake alkalinecomplex, northwest Territories.Msc. Thesis, University Of Alberta, Northwest TerritoriesAlkaline rocks, mineral chemistry, Deposit -Spruce Lake complex
DS1996-0687
1996
DaiJin, Bai, Fengyan, DaiThe early Precambrian crustal evolution of ChinaJournal of Southeast Asian Earth Sciences, Vol. 13, No. 3/5, pp. 205-214ChinaPrecambrian, Structure, tectonics
DS2003-1530
2003
DaiYong, X., De Lian Liu, Dai, Jin-XingExtremely h2 rich fluid inclusions in eclogite from the Dabie Shan orogenic belt, EasternJournal of the Geological Society of India, Vol. 61, 1, Jan., pp. 101-102.ChinaUHP
DS201312-0561
2014
Dai, B-Z.Ma, L., Jiang, S-Y., Hofman, A.W., Dai, B-Z., Hou, M-L., Zhao, K-D, Chen, L-H., Jiang, Y.H.Lithospheric and asthenospheric sources of lamprophyres in the Jiadong Peninsula: a consequence of rapid lithospheric thinning beneath the North Chin a craton?Geochimica et Cosmochimica Acta, Vol. 124, pp. 250-271.ChinaLamprophyre
DS201605-0863
2016
Dai, B-Z.Ma, L., Jiang, S-Y., Hofmann, A.W., Xu, Y-G, Dai, B-Z., Hou, M-L.Rapid lithospheric thinning of North Chin a craton: new evidence from Cretaceous mafic dikes in the Jiaodong Peninsula.Chemical Geology, Vol. 432, pp. 1-15.ChinaDikes

Abstract: The North China Craton is a classic case for the destruction of an ancient craton, in that it records the loss of more than 100 km of ancient refractory lithospheric mantle during the late Mesozoic and early Cenozoic. However, the mechanisms for this lithospheric thinning remain controversial in large part due to the lack of any systematic investigations of the Mesozoic asthenospheric mantle via its derived mafic rocks, which are key to understand the thinning processes. In this paper, we present detailed zircon U-Pb geochronology, elemental geochemistry, and Sr-Nd-Hf isotopic data for lamprophyres and diabase-porphyries of the Jiaodong Peninsula, in the eastern North China Craton in order to place constraints on models for lithospheric thinning. Our results show that the lamprophyres and diabase-porphyries are derived from the convective asthenospheric mantle via different degrees of partial melting, and that this mantle source was previously modified by carbonatitic liquids. Zircon LA-ICP-MS U-Pb dating suggests an emplacement age for these rocks of 123-121 Ma, the earliest evidence for asthenospherically-derived melts in the Jiaodong Peninsula so far. This emplacement age indicates that the thickness of the lithosphere in the Jiaodong Peninsula was relatively thin at that time. Co-occurrence of the asthenospheric and lithospheric mantle-derived mafic rocks as well as high-Mg adakites record a rapid transition from lithospheric to asthenospheric mantle sources, indicating that the lithosphere beneath the Jiaodong Peninsula was rapidly detached just prior to ca. 120 Ma. Lithospheric thinning of the North China Craton may have been initiated from the Jiaodong Peninsula and Bohai Sea and then propagated towards the interior of the craton.
DS200412-0690
2004
Dai, F.Gong, Z., Fei, Y., Dai, F., Zhang, L., Jing, F.Equation of state and phase stability of mantle perovskite up to 140 GPa shock pressure and its geophysical implications.Geophysical Research Letters, Vol. 31, 4, Feb. 28, DOI 1029/2004 GLO19132MantleGeophysics - UHP
DS202010-1879
2020
Dai, H.Song, Z., Lu, T., Liu, H., Dai, H., Ke, J., Zhu, W., Zhang, J.Identification of Type IIa blue CVD diamonds from Huzhou SinoC semiconductor.Journal of Gemmology, Vol. 37, 3, pp. 306-313.Chinasynthetics

Abstract: Gemmological and spectroscopic characteristics are reported for two type IIa blue CVD synthetic diamonds from Huzhou SinoC Semiconductor Science and Technology Co. Ltd, China. These are the first relatively large (1.76 and 2.63 ct) blue CVD synthetics examined in NGTC’s laboratories, and their colour was slightly brighter than other blue synthetic diamonds that we have encountered. In the DiamondView, they fluoresced blue (with purple-red in one sample), which is unusual for CVD synthetics. The mid- and near-IR absorption spectra of one sample showed no hydrogen-related features, while the other synthetic diamond showed a weak absorption at 6853 cm-1attributed to hydrogen. The spectra of both samples had a very weak line at 1332 cm-1 due to isolated nitrogen and a distinct band at 9282 cm-1 related to radiation. A very strong GR1 absorption feature was detected by UV-Vis-NIR spectroscopy. Photoluminescence spectra obtained at liquid-nitrogen temperature recorded emissions related to radiation (mainly in the 480-510 nm region), N-V and [Si-V]- centres, and several unassigned weak emissions. This combination of optical centres strongly suggests that these samples underwent post-growth treatment to improve their transparency before they were irradiated to produce blue colouration.
DS202009-1622
2020
Dai, H-K.Dai, H-K., Zheng, J.P., Griffin, W.L., O'Reilly, S.Y., Xiong, Q., Ping, X., Chen, F-K., Lu, J.Pyroxenite xenoliths record complex melt impregnation in the deep lithosphere of the northwestern North China Craton.Journal of Petrology, 10.1093/petrology/egaa079 110p. PdfChinaxenoliths

Abstract: Transformation of refractory cratonic mantle into more fertile lithologies is the key to the fate of cratonic lithosphere. This process has been extensively studied in the eastern North China Craton (NCC) while that of its western part is still poorly constrained. A comprehensive study of newly-found pyroxenite xenoliths from the Langshan area, in the northwestern part of this craton is integrated with a regional synthesis of pyroxenite and peridotite xenoliths to constrain the petrogenesis of the pyroxenites and provide an overview of the processes involved in the modification of the deep lithosphere. The Langshan pyroxenites are of two types, high-Mg# [Mg2+/(Mg2++Fe2+)*100 = ~ 90, atomic ratios] olivine-bearing websterites with high equilibration temperatures (880 ~ 970 oC), and low-Mg# (70 ~ 80) plagioclase-bearing websterites with low equilibration temperatures (550 ~ 835 oC). The high-Mg# pyroxenites show trade-off abundances of olivine and orthopyroxene, highly depleted bulk Sr-Nd (?Nd?=?+11.41, 87Sr/86Sr = ~0.7034) and low clinopyroxene Sr isotopic ratios (mean 87Sr/86Sr = ~0.703). They are considered to reflect the reaction of mantle peridotites with silica-rich silicate melts derived from the convective mantle. Their depletion in fusible components (e.g., FeO, TiO2 and Na2O) and progressive exhaustion of incompatible elements suggest melt extraction after their formation. The low-Mg# pyroxenites display layered structures, convex-upward rare earth element patterns, moderately enriched bulk Sr-Nd isotopic ratios (?Nd = -14.20 ~ -16.74, 87Sr/86Sr?=?0.7070 ~ 0.7078) and variable clinopyroxene Sr-isotope ratios (87Sr/86Sr?=?0.706-0.711). They are interpreted to be crustal cumulates from hypersthene-normative melts generated by interaction between the asthenosphere and heterogeneous lithospheric mantle. Combined with studies on regional peridotite xenoliths, it is shown that the thinning and refertilization of the lithospheric mantle was accompanied by crustal rejuvenation and that such processes occurred ubiquitously in the northwestern part of the NCC. A geodynamic model is proposed for the evolution of the deep lithosphere, which includes long-term mass transfer through a mantle wedge into the deep crust from the Paleozoic to the Cenozoic, triggered by subduction of the Paleo-Asian ocean and the Late Mesozoic lithospheric extension of eastern Asia.
DS2001-1279
2001
Dai, J.Yang, X.Y., Zheng, Y.F., Liu, D., Dai, J.Chemical and carbon isotope compositions of fluid inclusions in peridotite xenoliths and eclogites...Physics and Chemistry of the Earth Pt. A. Solid Earth, Vol. 26, No. 9-10, pp. 705-18.ChinaGeodynamics
DS2001-1280
2001
Dai, J.Yang, X.Y., Zheng, Y.F., Liu, D., Dai, J.Chemical and carbon isotope compositions of igneous rocks from Lower Yangtze region, constraints on sourcesPhysics and Chemistry of the Earth, Vol. 26, pt. A. No. 9-10, pp. 705-18.ChinaPeridotite - xenoliths
DS2003-1531
2003
Dai, J-X.Yong-X, Liu, D-L., Dai, J-X.Extremely H2 rich fluid inclusions in eclogite from Dabie Shan orogenic belt, easternJournal of the Geological Society of India, Vol. 61, Jan. pp. 101-2.China, eastEclogite
DS200412-2184
2003
Dai, J-X.Yong-X, Liu, D-L., Dai, J-X.Extremely H2 rich fluid inclusions in eclogite from Dabie Shan orogenic belt, eastern China.Journal of the Geological Society of India, Vol. 61, Jan. pp. 101-2.ChinaEclogite
DS200812-0658
2008
Dai, L.Li, S., Jin, C., Dai, L., Liu, X., Zhou, X.Thermochronological constraints to two stage Indonesian extrusion of the HP UHP terranes in the Dabie Sulu orogen, central Chine.Goldschmidt Conference 2008, Abstract p.A544.ChinaUHP
DS201806-1219
2018
Dai, L.Dai, L., Li, S., Li, Z-H., Somerville, I., Santosh, M.Dynamics of exhumation and deformation of HP-UHP orogens in double subduction collision systems: numerical modeling and implications for the Western Dabie Orogen.Earth Science Reviews, Vol. 182, pp. 68-84.ChinaUHP

Abstract: The dynamics of formation and exhumation of high-pressure (HP) and ultra-high pressure (UHP) metamorphic orogens in double subduction-collision zones remain enigmatic. Here we employ two-dimensional thermo-mechanical numerical models to gain insights on the exhumation of HP-UHP metamorphic rocks, as well as their deformation during the collision of a micro-continent with pro- and retro-continental margins along two subduction zones. A three-stage collisional process with different convergence velocities is tested. In the initial collisional stage, a fold-and-thrust belt and locally rootless superimposed folds are developed in the micro-continent and subduction channel, respectively. In the second (exhumation) stage of HP-UHP rocks, a faster convergence model results in upwelling of the asthenosphere, which further leads to a detachment between the crust and lithospheric mantle of the micro-continent. A slower convergence model results in rapid exhumation of HP-UHP rocks along the north subduction channel and a typical piggy-back thrusting structure in the micro-continent. A non-convergence model produces a slab tear-off, leading to the rebound of residual lithosphere of the micro-continent. In the third and final stage, a series of back and ramp thrusts are formed in the micro-continent with the pro-continent re-subducted. Based on an analogy of our numerical results with the Western Dabie Orogen (WDO), we suggest that: (1) slab tear-off results in a rebound of residual lithosphere, which controls the two-stage syn-collisional exhumation process of HP-UHP rocks in the WDO; and (2) in contrast to the single subduction-collision system, the exhumation range of the partially molten rocks with lower viscosity and density is restricted to a specific region of the micro-continent by the Mianlue and Shangdan subduction zones, which generated the complex deformation features in the WDO.
DS201112-0233
2011
Dai, L-Q.Dai, L-Q., Zhao, Z-F., Zheng, Y-F.Zircon Hf-O isotope evidence for crust mantle interaction during continental deep subduction.Goldschmidt Conference 2011, abstract p.713.ChinaDabie Orogen, geochronology
DS201112-0234
2011
Dai, L-Q.Dai, L-Q., Zhao, Z-F., Zheng, Y-F., Li, Q., Yang, Y., Dai, M.Zircon Hf-O isotope evidence for crust mantle interaction during continental deep subduction.Earth and Planetary Science Letters, Vol. 308, 1-2, pp. 229-244.MantleSubduction
DS201212-0138
2012
Dai, L-Q.Dai, L-Q., Zhao, Z-F., Zheng, Y-F., Zhang, J.The nature of orogenic lithospheric mantle: geochemical constraints from Post collisional mafic-ultramafic rocks in the Dabie orogen.Chemical Geology, Vol. 334, pp. 99-121.ChinaUHP
DS201708-1617
2017
Dai, L-Q.Dai, L-Q.Geochemical evidence for carbonated metasomatite as the mantle source of Cenozoic alkali basalts in western Qinling, Cjina.11th. International Kimberlite Conference, PosterChinametasomatism
DS201112-0178
2011
Dai, M.Chen, Y.X., Zheng, Y-F., Chen, R-X., Zhang, S-B., Li, Q., Dai, M., Chen, L.Metamorphic growth and recrystallization of zircons in extremely 18 O depleted rocks during eclogite facies metamorphism: evidence from U-Pb ages, trace elements and O-Hf isotopes.Geochimica et Cosmochimica Acta, Vol. 75, 17, pp. 4877-4898.MantleMetamorphic zircons
DS201112-0234
2011
Dai, M.Dai, L-Q., Zhao, Z-F., Zheng, Y-F., Li, Q., Yang, Y., Dai, M.Zircon Hf-O isotope evidence for crust mantle interaction during continental deep subduction.Earth and Planetary Science Letters, Vol. 308, 1-2, pp. 229-244.MantleSubduction
DS200712-0213
2007
Dai, S.Dai, S., Young, J.P., Begun, G.M., Mamantov, G.Temperature measurement by observation of the Raman spectrum of diamond.Applied Spectroscopy, Vol. 46, 2, pp. 375-377.TechnologySpectroscopy
DS201907-1588
2019
Dai, T.Zhang, D., Liu, Y., Pan, J., Dai, T., Bayless, R.C.Mineralogical and geochemical characteristics of the Miaoya REE prospect, Qinling orogenic belt, China: insights from Sr-Nd-C-O isotopes and LA-ICP-MS mineral chemistry.Ore Geology Reviews, Vol. 110, 18p.Chinacarbonatites

Abstract: Most carbonatite-related REE (rare earth element) deposits record two stages of REE enrichment: magmatic and magmatic-hydrothermal. It is generally accepted that the first stage of enrichment, which occurs in magmas associated with carbonatite-syenite complexes, is a prerequisite to the formation of REE deposits. The magmatic-hydrothermal process is also important, as demonstrated by the fact that many fertile carbonatite-syenite complexes do not produce REE deposits. The Miaoya carbonatite-syenite complex is prospective for REE and is ideal for studies of the formation of REE deposits. The Miaoya REE prospect lies in the western member of the Wudan Terrane of the Qinling Belt, China, and is hosted by a carbonatite-syenite complex that was intruded along a fault zone between schist of the lower Silurian Meiziya Group and adjacent Proterozoic quartzite. Mineralization at the Miaoya REE prospect includes carbonatite-, syenite-, and mixed-type, all low grade (about 1%). Results of X-ray diffraction (XRD) and electron probe micro-analyzer (EMPA) analyses reveal that modes of REE minerals are low in all samples (<5%), which is consistent with the fact that less monazite, bastnäsite and other REE minerals have been found in the Miaoya REE prospect. REE mineralization is less likely to occur as an overprint on gangue minerals. Results of Photon Laser Ablation Inductively-Coupled-Plasma Mass-Spectrometer (LA-ICP-MS) analyses reveal that apatite and calcite in carbonatite have the highest REE concentrations which are responsible for the relatively high concentration in carbonatite rather than because of the presence of REE minerals. The consistence of Sr-Nd isotopes ratios between altered host rocks and fresh hosted rocks suggested REE mineralization originates directly from the unmineralized carbonatite-syenite complex rather than other host rocks. Carbon and oxygen isotope ratios of hydrothermal calcite are consistent with low-temperature alteration subsequent to ore. Trace element ratios for the Miaoya carbonatite-syenite complex lie in the barren carbonatite field (REEs vs. CaO/MgO, FeO/MgO, Ba and Sr/Ba) compared with those of other giant or large carbonatite-syenite complex related REE deposits, just below the boundary between fields for fertile and barren carbonatites. This suggests that the carbonatite-syenite complex at the Miaoya prospect did not have the potential to produce large or giant REE deposits. The low REE of the Miaoya prospect compared with other carbonatite-syenite hosted deposits may reflect: 1) as supported by petrography, minimal tectonic deformation in the area resulting in 2) restricted cycling of hydrothermal solutions that led to 3) minimal fluid scavenging from REE-rich apatite and calcite for local REE re-deposition and concentration.
DS201909-2106
2019
Dai, Y.Wang, T., Gao, S.S., Dai, Y., Yang, Q., Liu, K.H.Lithospheric structure and evolution of southern Africa: constraints from joint inversion of Rayleigh wave dispersion and receiver functions.Geochemistry, Geophysics, Geosystems, Vol. 20, 7, pp. 3311-3327.Africa, South Africageophysics

Abstract: We conduct a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion from both ambient noise and earthquakes using data from 79 seismic stations in southern Africa, which is home to some of the world's oldest cratons and orogenic belts. The area has experienced two of the largest igneous activities in the world (the Okavango dyke swarm and Bushveld mafic intrusion) and thus is an ideal locale for investigating continental formation and evolution. The resulting 3-D shear wave velocities for the depth range of 0-100 km and crustal thickness measurements show a clear spatial correspondence with known geological features observed on the surface. Higher than normal mantle velocities found beneath the southern part of the Kaapvaal craton are consistent with the basalt removal model for the formation of cratonic lithosphere. In contrast, the Bushveld complex situated within the northern part of the craton is characterized by a thicker crust and higher crustal Vp/Vs but lower mantle velocities, which are indicative of crustal underplating of mafic materials and lithospheric refertilization by the world's largest layered mafic igneous intrusion. The thickened crust and relatively low elevation observed in the Limpopo belt, which is a late Archean collisional zone between the Kaapvaal and Zimbabwe cratons, can be explained by eclogitization of the basaltic lower crust. The study also finds evidence for the presence of a stalled segment of oceanic lithosphere beneath the southern margin of the Proterozoic Namaqua-Natal mobile belt.
DS2003-0604
2003
Dai, Y.B.Hu, X.J., Dai, Y.B., Li, R.B., Shen, H.S., He, X.C.A molecular dynamics study of interstitial boron in diamondPhysica B, Vol. 327, 1, pp. 39-42.GlobalDiamond morphology
DS200512-1239
2005
Dai, Y.T.Zhang, B., Guo, W.L., Dai, Y.T.Touch graphite and turn it into diamond? Physical mechanics of carbon matters under ultrahigh pressure.Physics Review Letters, Vol. 34, 7, pp. 498-502.TechnologyCarbon
DS200512-0306
2005
Dai, Z.Fu, R., Wang, J., Chang, X., Huang, J., Dai, Z., Zha, X.Upper mantle convection driving by density anomaly and a test model.Acta Seismologica Sinica, Vol. 18, 1, pp. 27-33.MantleGeophysics - seismics
DS200812-1290
2008
Dai, Z.Yang, F., Liu, B., Ni, S., Zeng, X., Dai, Z., Li, Y.Lowermost mantle shear velocity anisotropy beneath Siberia.Acta Seismologica Sinica, Vol. 21, 3, pp. 213-216.RussiaGeophysics - seismics
DS1990-0941
1990
Dai CanfaLiu Yongxian, Dai CanfaThe research on the mineralogy of the calcium chrome garnet of gem trade at a district in TibetInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 680-682ChinaMineralogy, Garnet (pyrope)
DS1994-0365
1994
Dai UluDai UluThe chemical mineralogy and magma evolution of the Big Spruce Lake alkalinecomplex, northwest Territories.University of of Edmonton, MSc. thesisNorthwest TerritoriesAlkaline complex, Thesis
DS1998-0298
1998
Daigle, L.Daigle, L., Barron, L.M.Features about some alluvial diamonds from Wellington and Kalimantan, IndonesiaGeological Survey of New South Wales Department of Mineral Resources, Unpublished Petrological Report 98/5, 12p.Australia, New South Wales, IndonesiaDeposit - Wellington, Munt Airly, Victoria, Kimberley
DS200412-0399
1998
Daigle, L.Daigle, L., Barron, L.M.Features of Espinhaco diamonds in Minas Gerais Brasil, and their enigmaticsource area.Geological Survey of New South Wales Department of Mineral Resources, Unpublished Petrological Report 98/5, 12p.Australia, New South Wales, IndonesiaDiamond - morphology, Wellington, Mount Airly, Victoria
DS1996-1005
1996
Daigneault, R.Mueller, W.U., Daigneault, R., Chown, E.H.Archean terrane docking: upper crust collision tectonics, Abitibi Greenstone belt, QuebecTectonophysics, Vol. 265, No. 1/2, Nov. 15, pp. 127-150QuebecTectonics, Abitibi belt
DS1992-0248
1992
Daignieres, M.Chery, J., Lucazeau, F., Daignieres, M., Vilotte, J.P.Large uplift of rift flanks: a genetic link with lithospheric rigidity?Earth and Planetary Science Letters, Vol. 112, pp. 195-212Red Sea, Rhine, East Africa, Baikal, RussiaMantle structure MRDU, Rifting
DS1999-0249
1999
Daignieres, M.Gerbault, M., Burov, E., Daignieres, M.Do faults trigger folding in the lithosphere?Geophysical Research Letters, Vol. 26, No. 2, Jan. 15, pp. 271-74.MantleTectonics, Lithosphere
DS1990-0386
1990
Daily News (Perth)Daily News (Perth)Sea diamond exploration -Cambridge Gulf exploration North KimberleyregionIndiaqua, No. 55 1990/1, pp. 34AustraliaNews item, Cambridge Shelf
DS1992-0324
1992
Daines, M.J.Daines, M.J., Kohlstedt, D.L.Kenetics and dynamics of melt migration in upper mantle rocksV.m. Goldschmidt Conference Program And Abstracts, Held May 8-10th. Reston, p. A 25. abstractMantleMelt, Geochemistry
DS1997-0236
1997
Daines, M.J.Daines, M.J., Kolhlstedt, D.L.Influence of deformation on melt topology in peridotitesJournal of Geophysical Research, Vol. 102, No. 5, May 10, pp. 10257-72.MantleMelt, magma
DS201906-1293
2019
Dainis, I.Gain, S.E.M., Greau, Y., Henry, H., Belousova, E., Dainis, I., Griffin, W.L., O'Reilly, S.Y.Mud Tank zircon: long term evaluation of a reference material for U-Pb dating, Hf-isotope analysis and trace element analysis. ( Carbonatite)Geostandards and Geoanalytical Research, in press available, 16p.Australiadeposit - Mud Tank

Abstract: Zircon megacrysts from the Mud Tank carbonatite, Australia, are being used in many laboratories as a reference material for LA-ICP-MS U-Pb dating and trace element measurement, and LA-MC-ICP-MS determination of Hf isotopes. We summarise a database of > 10000 analyses of Mud Tank zircon (MTZ), collected from 2000 to 2018 during its use as a secondary reference material for simultaneous U-Pb and trace element analysis, and for Hf-isotope analysis. Trace element mass fractions are highest in dark red-brown stones and lowest in colourless and gem-quality ones. Individual unzoned grains can be chemically homogeneous, while significant variations in trace element mass fraction are associated with oscillatory zoning. Chondrite-normalised trace element patterns are essentially parallel over large mass fraction ranges. A Concordia age of 731.0 ± 0.2 Ma (2s, n = 2272) is taken as the age of crystallisation. Some grains show lower concordant to mildly discordant ages, probably reflecting minor Pb loss associated with cooling and the Alice Springs Orogeny (450-300 Ma). Our weighted mean 176Hf/177Hf is 0.282523 ± 10 (2s, n = 9350); the uncertainties on this ratio reflect some heterogeneity, mainly between grains. A few analyses suggest that colourless grains have generally lower 176Hf/177Hf. MTZ is a useful secondary reference material for U-Pb and Hf-isotope analysis, but individual grains need to be carefully selected using CL imaging and tested for homogeneity, and ideally should be standardised by solution analysis.
DS1996-0322
1996
Daizhi, L.Daizhi, L.Study on the dynamic mechanism of the Qinghai-Xizang (Tibet) PlateauupliftGlobal Tectonics and Metallogeny, Vol. 6, No. 1, pp. 9-17China, TibetGeodynamics, Plateau uplift
DS201212-0439
2012
Dak, A.I.Malkovets, V.G., Griffin, W.L., Pokhilenko, N.P., O'Reilly, S.Y., Dak, A.I., Tolstov, A.V., Serov, I.V., Bazhan, I.S., Kuzmin, D.V.Lithosphere mantle structure beneath the Nakyn kimberlite field, Yakutia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Nakyn
DS1930-0134
1933
Dake, H.C.Dake, H.C.Uncommon and Rare Minerals of OregonOregon Miner., Vol. 1, No. 6, NOVEMBER P. 6.United States, Oregon, Rocky MountainsBlank
DS1960-0272
1962
Dakhya, L.M.Makhlayev, L.V., Volkhov, V.K., Dakhya, L.M.Discovery of the Kimberlites in the Kotui-meimecha DistrictNiiga, Info. Bulletin., No. 26, PP. L6-24, French Geological Survey (BRGM) TRANSLATION No.RussiaBlank
DS200512-0202
2005
Dal Forno, G.Dal Forno, G., Gasperini, P., Boschi, E.Linear or nonlinear rheology in the mantle: a 3 D finite element approach to Post glacial rebound modeling.Journal of Geodynamics, Vol. 39, 2, pp. 183-195.MantleRheology, Laurentia, sea-level
DS1986-0160
1986
Dal Negro, A.Cundari, J.B., Dal Negro, A., Piccirillo, E.M., Della Gusta, A., SeccoIntracrystalline relationships in olivine, orthopyroxene, clinopyroxeneContributions to Mineralogy and Petrology, Vol. 94, No. 4, pp. 523-532AustraliaXenoliths, Mineralogy
DS1987-0132
1987
Dal Negro, A.Dal Negro, A., Cundari, A., Piccirillo, E.M., Salviulo, G.Genetic significance of the clinopyroxene from lamproites and relatedrocks: a crystal chemical studyTerra Cognita, Conference abstracts Oceanic and Continental Lithosphere:, Vol. 7, No. 4, Autumn, abstract only p. 610AustraliaBlank
DS200912-0534
2009
Dal Negro, A.Nestola, F., Smyth, J.R., Parisatto, M., Secco, L., Princivalle, F., Bruno, M., Prencipe, M., Dal Negro, A.Effects of non-stochiometry on the spinel structure at high pressure: implications for Earth's mantle mineralogy.Geochimica et Cosmochimica Acta, Vol. 73, 2, pp. 489-492.MantleUHP
DS201212-0574
2012
Dal Negro, A.Princivalle, F., Martignago, F., Nestola, F., Dal Negro, A.Kinetics of cation ordering in synthetic Mg(Al,Fe3+2O4 spinels.European Journal of Mineralogy, Vol. 24, 4, pp. 633-643.TechnologySpinel
DS201707-1317
2017
Dal Zilio, L.Dal Zilio, L., Faccenda, M., Capitanio, F.The role of deep subduction in supercontinental breakup.Tectonophysics, in press availableMantlesubduction

Abstract: The breakup of continents and their subsequent drifting plays a crucial role in the Earth's periodic plate aggregation and dispersal cycles. While continental aggregation is considered the result of oceanic closure during subduction, what drives sustained divergence in the following stages remains poorly understood. In this study, thermo-mechanical numerical experiments illustrate the single contribution of subduction and coupled mantle flow to the rifting and drifting of continents. We quantify the drag exerted by subduction-induced mantle flow along the basal surface of continental plates, comparing models of lithospheric slab stagnation above the upper-lower mantle boundary with those where slabs penetrate into the lower mantle. When subduction is upper-mantle confined, divergent basal tractions localise at distances comparable to the effective upper mantle thickness (~ 500 km), causing the opening of a marginal basin. Instead, subduction of lithosphere in the lower mantle reorganises the flow into a much wider cell localising extensional stresses at greater distances from the trench (~ 3000 km). Sub-continental tractions are higher and more sustained over longer time periods in this case, and progressively increase as the slab sinks deeper. Although relatively low, basal-shear stresses when integrated over large plates, generate tension forces that may exceed the strength of the continental lithosphere, eventually leading to breakup and opening of a distal basin. The models illustrate the emergence of a similar mechanism, which results in the formation of back-arc basins above upper-mantle confined subduction, and scales to much larger distances for deeper subduction. Examples include the Atlantic Ocean formation and drifting of the South and North American plates during the Mesozoic-Cenozoic Farallon plate subduction.
DS201901-0024
2018
Dal Zilio, L.Dal Zilio, L., Faccenda, M., Capitanio, F.The role of deep subduction in supercontinent breakup.Tectonophysics, Vol. 746, pp. 312-324.Mantleplate tectonics

Abstract: The breakup of continents and their subsequent drifting plays a crucial role in the Earth's periodic plate aggregation and dispersal cycles. While continental aggregation is considered the result of oceanic closure during subduction, what drives sustained divergence in the following stages remains poorly understood. In this study, thermo-mechanical numerical experiments illustrate the single contribution of subduction and coupled mantle flow to the rifting and drifting of continents. We quantify the drag exerted by subduction-induced mantle flow along the basal surface of continental plates, comparing models of lithospheric slab stagnation above the upper-lower mantle boundary with those where slabs penetrate into the lower mantle. When subduction is upper-mantle confined, divergent basal tractions localise at distances comparable to the effective upper mantle thickness (~ 500 km), causing the opening of a marginal basin. Instead, subduction of lithosphere in the lower mantle reorganises the flow into a much wider cell localising extensional stresses at greater distances from the trench (~ 3000 km). Sub-continental tractions are higher and more sustained over longer time periods in this case, and progressively increase as the slab sinks deeper. Although relatively low, basal-shear stresses when integrated over large plates, generate tension forces that may exceed the strength of the continental lithosphere, eventually leading to breakup and opening of a distal basin. The models illustrate the emergence of a similar mechanism, which results in the formation of back-arc basins above upper-mantle confined subduction, and scales to much larger distances for deeper subduction. Examples include the Atlantic Ocean formation and drifting of the South and North American plates during the Mesozoic-Cenozoic Farallon plate subduction.
DS201610-1855
2016
Dalaison, M.Dalaison, M., Davies, R.Lithospheric thinning by mantle plumes.ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 4p.MantleHotspots

Abstract: Thermo-mechanical thinning of the lithosphere by mantle plumes is essential for intra-plate volcanism, the initiation of rifting, the evolution of Earth’s lower continental crust and the genesis of metals, diamonds and hydrocarbons. To develop a new understanding of how a mantle plume thins the overlying lithosphere beneath moving plates, we use 2-D and 3-D numerical models based on a finite-element discretization on anisotropic adaptive meshes. Our models include Earth-like material properties for the upper mantle (e.g. temperature and viscosity contrasts, non-Newtonian rheology) discretised at a local mesh resolution that has previously been considered intractable. In our simulations, a plume is injected at the base of the model (670 km depth) with a prescribed mass flux that is consistent with surface observations of topographic swells: from 0.5 (e.g. Louisville, Bermuda, Darfur) to 7 Mg/s (Hawaii). We undertake a systematic numerical study, across a wide parameter space, to investigate the effect of plume buoyancy flux, plate velocity, rheology law and Rayleigh number on processes leading to a reduction of the depth of the Lithosphere Asthenosphere boundary (LAB), such as small-scale convection (SSC) (‘dripping’), or delamination of the lower lithosphere.
DS2001-0223
2001
Dalati, M.Dalati, M.Lineaments on Land sat images detection mapping and tectonic significance north western depressions SyriaInternational Archives Photogrammetry and Remote Sensing, Vol.33,B7/1,pp.301-5.SyriaTectonics, Remote sensing
DS200612-0996
2006
Dalconi, M.C.Oberti, R., Quartieri, S., Dalconi, M.C., Boscherini, F., Iezzi, G., Boiocchi, M., Eeckhout, S.G.Site preference and local geometry of Sc in garnets: part 1. multifarious mechanisms in the pyrope-grossular join.American Mineralogist, Vol. 91, 9, pp. 1230-1239.TechnologyMineral chemistry - garnets
DS200812-1261
2008
Dale, C.W.Wittig, N., Webb, M.,Pearson, D.G., Dale, C.W., Ottley, C.J., Luguet, A., Jensen, S.M.Lithosphere stabilization ages beneath sw Greenland.Goldschmidt Conference 2008, Abstract p.A1030.Europe, GreenlandNorth Atlantic Craton, kimberlites
DS200912-0143
2009
Dale, C.W.Dale, C.W., Pearson, D.G., Starkey, N.A., Stuart, F.M., Ellam, Larsen, Fitton, MacPhersonOsmium isotope insights into high 3He4He mantle and convecting mantle in the North Atlantic.Goldschmidt Conference 2009, p. A260 Abstract.Canada, Nunavut, Baffin Island, Europe, GreenlandPicrite
DS200912-0144
2009
Dale, C.W.Dale, C.W., Pearson, D.G., Starkey, N.A., Stuart, F.M., Ellam, R.M., Larsen, L.M., Fitton, J.G., Grousset, F.E.Osmium isotopes in Baffin Island and West Greenland picrites: implications for the 187 Os and 188 Os composition of the convection mantle and nature 3He/4heEarth and Planetary Interiors, Vol. 278, 3-4, pp. 267-277.MantleConvection
DS200912-0330
2009
Dale, C.W.Ishikawa, A., Pearson, D.G., Dale, C.W.Re Os isotopes and platinum group elements in a peridotite pyroxenite hydrid mantle.Goldschmidt Conference 2009, p. A572 Abstract.MantleMagmatism
DS201012-0854
2010
Dale, C.W.Wittig, N., Webb, M., Pearson, D.G., Dale, C.W., Ottley, C.J., Hutchison, M., Jensen, S.M., Luget, A.Formation of the North Atlantic craton: timing and mechanisms constrained from Re-Os isotope and PGE dat a of peridotite xenoliths from S.W. Greenland.Chemical Geology, Vol. 276, 3-4, pp. 166-187.Europe, GreenlandCraton
DS201012-0855
2010
Dale, C.W.Wittig, N., Webb, M., Pearson, D.G., Dale, C.W., Ottley, C.J., Hutchison, M., Jensen, S.M., Luget, A.Formation of the North Atlantic craton: timing and mechanisms constrained from Re-Os isotope and PGE dat a of peridotite xenoliths from S.W. Greenland.Chemical Geology, Vol. 276, 3-4, pp. 166-187.Europe, GreenlandCraton
DS201112-0416
2011
Dale, C.W.Harvey, J., Dale, C.W., Gannoun, A., Burton, K.W.Osmium mass balance in peridotite and the effects of mantle derived sulphides on basalt petrogenesis.Geochimica et Cosmochimica Acta, Vol. 75, 9, pp. 5574-5596.United States, New Mexico, Colorado PlateauKilbourne
DS201112-0774
2011
Dale, C.W.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
DS201212-0324
2012
Dale, C.W.Hutchison, M.T., Dale, C.W., Nowell, G.M., Pearson, D.G.Age constraints on ultra deep mantle petrology shown by Juin a diamonds.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Juina
DS201412-0548
2014
Dale, C.W.Marchesi, C., Dale, C.W., Garrdo, C.J., Pearson, D.G., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Fractionation of highly siderophile elements in refertilized mantle: implications for the Os isotope composition of basalts.Earth and Planetary Science Letters, Vol. 400, pp. 33-44.MantleRonda peridotite
DS1984-0716
1984
Dale, M.L.Sutherland, D.G., Dale, M.L.Method of Establishing the Minimum Sample Size for Sampling alluvial Diamond Deposits.Institute of Mining and Metallurgy. Transactions, Vol. 93, SECT. B, PP. B55-B58.West Africa, Sierra Leone, Ghana, Central African RepublicAlluvial Placer Sampling
DS202012-2223
2020
Dale, M.W.Jones, D.C., Kumar, S., Lanigan, P.M.P., McGuiness, C.D., Dale, M.W., Twichen, D.J., Fisher, D., Martineau, P.M., Neil, M.A., Dunsby, C., French, P.M.W.Multidemensional luminescence microscope for imaging defect colour centres in diamond.Methods and Applications in Flouresence, Vol. 8, 1, 01404 htpp:dx.doi.org/10.1088/2050-6120/ab4eacGloballuminescence

Abstract: We report a multidimensional luminescence microscope providing hyperspectral imaging and time-resolved (luminescence lifetime) imaging for the study of luminescent diamond defects. The instrument includes crossed-polariser white light transmission microscopy to reveal any birefringence that would indicate strain in the diamond lattice. We demonstrate the application of this new instrument to detect defects in natural and synthetic diamonds including N3, nitrogen and silicon vacancies. Hyperspectral imaging provides contrast that is not apparent in conventional intensity images and the luminescence lifetime provides further contrast.
DS1992-0325
1992
Daley, E.E.Daley, E.E., DePaolo, D.J.Isotopic evidence for a fundamental difference between Basin and Range and Colorado Plateau lithospheric mantleEos, Transactions, Annual Fall Meeting Abstracts, Vol. 73, No. 43, October 27, abstracts p. 655Colorado PlateauMantle, Geochronology
DS1992-0326
1992
Daley, E.E.Daley, E.E., DePaolo, D.J.Isotopic evidence for lithospheric thinning during extension: southeastern Great BasinGeology, Vol. 20, No. 2, February pp. 104-108NevadaGreat Basin, Tectonics
DS1998-0323
1998
Daley, E.E.De Paolo, D.J., Daley, E.E.Isotopic evidence for nonuniform thinning of lithospheric mantle during continental extension.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 364-5.MantleBasalts - Basin and Range
DS2000-0214
2000
Daley, E.E.De Paolo, D.J., Daley, E.E.Neodynium isotopes in basalts of the southwest basin and range and lithospheric thinning .. cont. extensionChemical Geology, Vol. 169, No. 3-4, Sept. pp. 157-186.Colorado PlateauGeochronology, Continent - extension
DS200412-0615
2004
DalForno, G.Gasperini, P., DalForno, G., Boschi, E.Linear or non-linear rheology in the Earth's mantle: the prevalence of power law creep in the Post glacial isostatic readjustmentGeophysical Journal International, Vol. 157, 3, pp. 1297-1302.Mantle, LaurentiaTectonics, subduction
DS1993-0044
1993
Dalgren, S.Arzamastsev, A.A., Dalgren, S.Abyssal mineral associations in dikes and kimberlite pipes of Paleozoic alkaline province of the Baltic shield. (Russian)Geochemistry International (Geokhimiya), (Russian), No. 8, August pp. 1132-1142Russia, Commonwealth of Independent States (CIS), Baltic shieldKimberlites, Geochemistry
DS201212-0769
2012
Dalheimer, M.Wellmer, F.W., Dalheimer, M.The feedback control cycle as regulator of past and future mineral supply.Mineralium Deposita, Vol. 47, 7, pp. 713-729.GlobalSupply and demand risk
DS1970-0029
1970
Dall, A.E.Borchers, D., Stocken, C.G., Dall, A.E.Beach Mining at Consolidated Diamond Mines of Southwest Africa Limited: Exploitation of the Area between the High and Low Water Marks.Commonwealth Min. Met. Congress 9th., Vol. 1, PP. 571-590.Southwest Africa, NamibiaPlacers, Diamond Mining Recovery, Littoral
DS1989-0935
1989
DallaMareschal, J.C., Pinet, C., Gariepy, C., Jaupart, C., Bienfait, G., DallaNew heat flow density and radiogenic heat productiondat a in the Canadian Shield and the QuebecAppalachiansCanadian Journal of Earth Sciences, Vol. 26, No. 4, April pp. 845-852QuebecCraton, Heat Flow
DS202008-1402
2020
Dalla Costa, M.Jalowitzki, T., Gervasoni, F., Sumino, H., Klemme, S., Berndt, J., Dalla Costa, M., Fuck, R.A.Plume subduction events recorded by KS2 kimberlite indicator minerals from Juina, Brazil.Goldschmidt 2020, 1p. AbstractSouth America, Brazil, Mato Grossodeposit - Juina

Abstract: The Cretaceous Juína Kimberlite Province (JKP, 95-92 Ma) is located in the southwest of the Amazonian Craton, northwest of Mato Grosso, Brazil. Here we present new geochemical and isotopic data of garnet (n=187) and zircon (n=25) megacrysts collected from the KS2 kimberlite. The magmatic zircon megacrysts have U-Pb ages of 92.1 ± 0.7 Ma. The chondrite-normalized rare earth element (REE) patterns (LREE
DS201910-2294
2019
Dalla Costa, M.M.Reis Jalowitski, T.L., Grings Cadeno, D., Veira Conceicao, R., Dalla Costa, M.M., Carvalho, A.M.G., Noqueira Neto, J.D.A.Are Juina diamonds, Super Deep diamonds?Goldschmidt2019, 1p. AbstractSouth America, Brazildeposit - Juina

Abstract: Super Deep Diamonds (SDD) are known to form at depths between ~300 and ~1000 km in the Earth’s mantle [1]. These diamonds as well as their minerals, melts and fluid inclusions are rare natural materials from deep Earth. The aim of this study is to indentify and characterize mineral inclusions in diamonds from Juína, Mato Grosso, Brazil, and hence classify them as SDD (or not). Twelve diamonds from four different mining sites of Juína were selected according to their inclusions using an Estereo Microscope. The main diamond features were based on crystallographic faces, shape, degrees of resportion, crystal state and intergrowing [2]. Diamond samples are transparent, colorless and present octahedro, octahedro-tetrahexahedral and tetrahexahedral habits. Some diamonds show trigons with positive and negative relief, and hexagons with negative relief. Four diamonds are heavily resorbed and were classified as "unknowing habits", as their shapes are distorced and fragmented. Moreover, three samples show abrasion on the vertices of the quartenary axes, and the others have distinct degrees of resorption. Some crystals present intergorwth, such as contact twins (macle) in {111} or aggregates. All diamonds have mineral inclusions of different colors. Most inclusions are black and could be carbon spots, oxides or even silicates, such as olivine. Other inclusions are yellow to red, which might indicate garnet. In addition, blue inclusions were observed, and could be sulphides. The next steps consists of Fourier Transform Infrared (FTIR) to determine diamond nitrogen impurities, and Micro-Raman spectroscopy and X-Ray Diffraction analyses using Synchrotron radiation to determine in situ the chemical composition of mineral inclusions.
DS1992-0327
1992
Dalla Salda, L.H.Dalla Salda, L.H., Dalziel, I.W.D., Cingolani, C.A., Varela, R.Did the Taconic Appalachians continue into southern South America?Geology, Vol. 20, No. 12, December pp. 1059-1062Appalachia, South America, ArgentinaTectonics, Orogeny
DS1996-0326
1996
Dalla Salda, L.H.Dalziel, I.W.D., Dalla Salda, L.H.The early Paleozoic evolution of the Argentine Pre Cordillera as a Laurentian rifted, drifted terrane:Geological Society of America (GSA) Bulletin, Vol. 108, No. 3, March pp. 372-375Argentina, CordilleraGeodynamics, Collided terrane
DS1996-1355
1996
Dalla Salda. L.H.Spalletti, L.A., Dalla Salda. L.H.A pull apart volcanic related Tertiary basin an example from the PatagonianAndes.Journal of South American Earth Sciences, Vol. 9, No. 3-4, pp. 197-206.Andes, Chile, ArgentinaTectonics - volcanism.
DS201212-0139
2012
Dalla-Costa, M.M.Dalla-Costa, M.M., Santos, R.V., Araujo, D.P., Gaspar, J.C.Occurrence of garnets with eclogitic and lherzolitic compositions in garnet lherzolite xenolith from the Canastra-01 kimberlite pipe, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Canastra-01
DS2000-0198
2000
Dallagnol, R.Dallagnol, R., Lafon, Fraga, Scandolara, BarrosThe Precambrian evolution of the Amazonian Craton: one of the last unknown Precambrian terranes in the world.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Guyana ShieldCraton - Amazon, Tectonics
DS2002-0330
2002
DallAgnol, R.Costi, H.T., DallAgnol,R., Borges, Minuzzi, TeixeiraTin bearing sodic episyenites associated with the Proterozoic a type Agua granite, Pitinga mine.Gondwana Research, Vol.5,2,pp.435-52.Brazil, Amazon CratonTin, Deposit - Pitinga
DS1994-0367
1994
Dall'Agnol, R.Dall'Agnol, R., Lafon, J-M., Macambira, M.J.B.Proterozoic anorogenic magmatism in the central Amazonian Province, Amazonian craton: geochronological, petrological and geochemical aspectsMineralogy and Petrology, Vo. 50, No. 1-3, pp. 113-138South AmericaGeochemistry, Petrology
DS200512-0307
2005
Dall'Agnol, R.Fuck, R.A., Dall'Agnol, R., Bettencourt, J.S.Volcanic rocks in Brazil through time and different tectonic settings.Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 233-235. (brief editorial)South America, BrazilTectonics
DS200512-0407
2004
Dall'agnol, R.Hartmann, L.A.,Milani, E.J., Schobbenhaus, C., Dall'agnol, R., Alkmim, F.F.The stratigraphy of Brazil: a continental scale task.Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 230-9, Vol. 36, 5, p. 532.South America, BrazilCraton, basins
DS200912-0145
2009
Dall'Agnol, R.Dall'Agnol, R., Fuck, R.A., Villas, R.N.N.Insights on the magmatism, crustal evolution and metallogenesis of the Amazonian craton.Journal of South American Earth Sciences, Vol. 27, 2-3, pp. 109-112.South America, BrazilMagmatism
DS200512-0287
2005
Dallai, L.Ferrando, S., Frezzotti, M.L., Dallai, L., Compagnoni, R.Fluid rock interaction in UHP phengite kyanite epidote eclogite from the Sulu Orogen, eastern China.International Geology Review, Vol. 47, 7, pp. 750-774.Asia, ChinaUHP
DS200612-0392
2005
Dallai, L.Ferrando, S., Frzzotti, M.L., Dallai, L., Compagnoni, R.Multiphase solid inclusions in UHP rocks ( Su-Lu, China): remnants of supercritical silicate rich aqueous fluids released during continental subduction.Chemical Geology, Vol. 223, 1-3, Nov. 22, pp. 68-81.ChinaUHP
DS200912-0063
2009
Dallai, L.Bonadiman, C., Yantao, H., Coltorti, M., Dallai, L., Faccini, B., Huang, YU., Xia, Q.Water content of pyroxenes in intraplate lithospheric mantle.European Journal of Mineralogy, Vol. 21, 3, June pp. 637-647.MantleWater
DS201509-0396
2015
Dallai, L.France, L., Chazot, G., Kornprobst, J., Dallai, L., Vannucci, R., Gregoire, M., Bertrand, H., Boivin, P.Mantle refertilization and magmatism in old orogenic regions: the role of late-orogenic pyroxenites.Lithos, Vol. 232, pp. 49-75.Africa, Morocco, Cameroon, Jordan, Europe, FranceXenoliths

Abstract: Pyroxenites and garnet pyroxenites are mantle heterogeneities characterized by a lower solidus temperature than the enclosing peridotites; it follows that they are preferentially involved during magma genesis. Constraining their origin, composition, and the interactions they underwent during their subsequent evolution is therefore essential to discuss the sources of magmatism in a given area. Pyroxenites could represent either recycling of crustal rocks in mantle domains or mantle originated rocks (formed either by olivine consuming melt-rock reactions or by crystal fractionation). Petrological and geochemical (major and trace elements, Sr-Nd and O isotopes) features of xenoliths from various occurrences (French Massif-Central, Jordan, Morocco and Cameroon) show that these samples represent cumulates crystallized during melt percolation at mantle conditions. They formed in mantle domains at pressures of 1-2 GPa during post-collisional magmatism (possibly Hercynian for the French Massif-Central, and Panafrican for Morocco, Jordan and Cameroon). The thermal re-equilibration of lithospheric domains, typical of the late orogenic exhumation stages, is also recorded by the samples. Most of the samples display a metasomatic overprint that may be either inherited or likely linked to the recent volcanic activity that occurred in the investigated regions. The crystallization of pyroxenites during late orogenic events has implications for the subsequent evolution of the mantle domains. The presence of large amounts of mantle pyroxenites in old orogenic regions indeed imparts peculiar physical and chemical characteristics to these domains. Among others, the global solidus temperature of the whole lithospheric domain will be lowered; in turn, this implies that old orogenic regions are refertilized zones where magmatic activity would be enhanced.
DS1997-0049
1997
Dallmeyer, P.Attoh, K., Dallmeyer, P.Chronology of nappe assembly in the Pan -African Dahomeyide Orogen, WestAfrica: evidence 40Ar/39Ar agesPrecambrian Research, Vol. 82, No. 1-2, March 1, pp. 153-West Africa, GhanaGeochronology, Orogeny
DS1987-0133
1987
Dallmeyer, R.D.Dallmeyer, R.D., Villeneuve, M.40Ar/39ar mineral age record of polyphase tectonothermal evolution in the southern Mauritanide orogen, southeastern SenegalGeological Society of America (GSA) Bulletin, Vol. 98, No. 5, May pp. 602-611GlobalWest Africa, Craton
DS1989-0325
1989
Dallmeyer, R.D.Dallmeyer, R.D.Contrasting accreted terranes in the southern Appalachian orogen basement beneath the Atlantic and Gulf coastal plains, and west African orogensPrecambrian Research, Vol. 42, pp. 387-409. Database # 17818Appalachia, West AfricaAccreted terranes, Tectonics
DS1989-0761
1989
Dallmeyer, R.D.Keppie, J.D., Dallmeyer, R.D.Tectonic map of Pre-Mesozoic terranes in circum- Atlantic PhanerozoicoceansKeppie, J.D. RR # 3, Wolfville, N.S. KOP lXO $ 30.00, 1: 5, 000, 000 International Geological Correlation Programme (IGCP) # 233AppalachiaMap, Tectonics
DS1991-0331
1991
Dallmeyer, R.D.Dallmeyer, R.D., Lecorche, J.P.The West African orogens and circum Atlantic correlativesSpringer-Verlag, 402pWest Africa, Spain, Europe, AppalachiaTectonics, structure, craton, orogeny, Terranes
DS1994-0668
1994
Dallmeyer, R.D.Grocott, J., Brown, M., Dallmeyer, R.D., Taylor, G.K., TreloarMechanisms of continental growth in extensional arcs: an example from the Andean plate boundary zoneGeology, Vol. 2, No. 5, May pp. 391-393Andes, ChileTectonics, Arcs
DS1994-1425
1994
Dallmeyer, R.D.Radhakrishna, T., Dallmeyer, R.D., Joseph, M.Paleomagnetism and 36 Ar-40 Ar vs 39 Ar-40 Ar isotope correlation ages of dyke swarms in central Kerala, India: tectonic implications.Earth and Planetary Science Letters, Vol. 121, No. 1/2, January pp. 213-226.IndiaDikes, isotope correlation, Argon, Tectonics
DS1994-1426
1994
Dallmeyer, R.D.Radhakrishna, T., Dallmeyer, R.D., Joseph, M.Paleomagnetism and 36 Ar-40Ar vs 39Ar-40r isotope correlation ages of dyke swarms in central Kerala, India: tectonic implications.Earth and Planetary Science Letters, Vol. 121, pp. 213-226.IndiaPaleomagnetics, Argon, Dykes
DS1996-0323
1996
Dallmeyer, R.D.Dallmeyer, R.D., Brown, M., Grocott, J., et al.Mesozoic magmatic and tectonic events within the Andean plate boundaryzone, North Chile: constraints 40Ar/39ArJournal of Geology, Vol. 104, No. 1, pp. 19-40ChileTectonics, Geochronology
DS1997-0050
1997
Dallmeyer, R.D.Attoh, K., Dallmeyer, R.D., Affaton, P.Chronology of nappe assembly in the Pan-African Dahomeyide orogen, WestAfrica: evidence from 40 Ar 39Precambrian Research, Vol. 82, No. 1-2, March pp. 153-172West Africa, GhanaGeochronology, Orogeny
DS1997-0571
1997
Dallmeyer, R.D.Karlstrom, K.E, Dallmeyer, R.D., Grambling, J.A.Ar-Ar evidence for 1.4 Ga regional metamorphism in New Mexico: Implications for thermal evolution of lithosph.Journal of Geology, Vol. 105, No. 2, March pp.205-223.United States, New MexicoThermal evolution, Argon, Lithosphere
DS1989-0326
1989
Dallmeyer, R.O.Dallmeyer, R.O.Late Paleozoic vs. late Proterozoic Pan African tectonothermal activity in the Mauritanide orogen,West AfricaGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 2, p. 11, (abstract.)West AfricaTectonics, Orogeny
DS201412-0058
2014
Dallwig, R.Boger, S.D., Hirdes, W., Ferreira, C.A.M., Jenett, T., Dallwig, R., Fanning, C.M.The 580-520 Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa.Gondwana Research, in press available 14p.Africa, MadagascarShield - Arabian Nubian
DS201509-0385
2015
Dallwig, R.Boger, S.D., Hirdes, W., Ferreira, C.A.M., Jenett, T., Dallwig, R., Fanning, C.M.The 580-520 Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa.Gondwana Research, Vol. 28, pp. 1048-1060.Africa, MadagascarTectonics

Abstract: U-Pb age data from southwest Madagascar provide a compelling case that the pre-Gondwana Indian plate was stitched with the arc terranes of the Arabian Nubian Shield along a suture that closed between 580 Ma and 520 Ma. The key observations supportive of this interpretation are: (1) metamorphism dated to 630-600 Ma is manifested only on the west side of the suture in rocks that have affinities with the oceanic and island arc terranes of the Arabian Nubian Shield, or which represent continental rocks welded to these terranes prior to the amalgamation of Gondwana, and (2) orogenesis at 580-520 Ma is manifest in rocks on both sides of the suture, an observation taken to mark the timing of collision and to reflect spatial continuity across the suture. In southwest Madagascar the distribution of metamorphic ages places the suture along the Beraketa high-strain zone, the tectonic boundary between the Androyen and Anosyen domains. Similar age relationships allow for the extrapolation of this tectonic boundary into both East Antarctica and Africa.
DS201905-1017
2019
Dallwig, R.Boger, S.D., Maas, R., Pastuhov, M., Macey, P.H., Hirdes, W., Schulte, B., Fanning, C.M., Ferreira, C.A.M., Jenett, T., Dallwig, R.The tectonic domains of southern and western Madagascar.Precambrian Research, Vol. 327, pp. 144-175.Africa, Madagascarplate tectonics

Abstract: Southern and western Madagascar is comprised of five tectonic provinces that, from northeast to southwest, are defined by the: (i) Ikalamavony, (ii) Anosyen, (iii) Androyen, (iv) Graphite and (v) Vohibory Domains. The Ikalamavony, Graphite and Vohibory Domains all have intermediate and felsic igneous protoliths of tonalite-trondhjemite-granodiorite-granite composition, with positive eNd, and low Sr and Pb isotopic ratios. All three domains are interpreted to be the products of intra-oceanic island arc magmatism. The protoliths of the Ikalamavony and Graphite Domains formed repectively between c. 1080-980?Ma and 1000-920?Ma, whereas those of the Vohibory Domain are younger and date to between c. 670-630?Ma. Different post-formation geologic histories tie the Vohibory-Graphite and Ikalamavony Domains to opposite sides of the pre-Gondwana Mozambique Ocean. By contrast, the Androyen and Anosyen Domains record long crustal histories. Intermediate to felsic igneous protoliths in the Androyen Domain are of Palaeoproterozoic age (c. 2200-1800?Ma), of tonalite-trondhjemite-granodiorite-granite composition, and show negative eNd, moderate to high 87Sr/86Sr and variable Pb isotopic compositions. The felsic igneous protoliths of the Anosyen Domain are of granitic composition and, when compared to felsic gneisses of the Androyen Domain, show consistently lower Sr/Y and markedly higher Sr and Pb isotope ratios. Like the Vohibory and Graphite Domains, the Androyen Domain can be linked to the western side of the Mozambique Ocean, while the Anosyen Domain shares magmatic and detrital zircon commonalities with the Ikalamavony Domain. It is consequently linked to the opposing eastern side of this ocean. The first common event observed in all domains dates to c. 580-520?Ma and marks the closure of the Mozambique Ocean. The trace of this suture lies along the boundary between the Androyen and Anosyen Domains and is defined by the Beraketa high-strain zone.
DS200812-0255
2009
Dalou, C.Dalou, C., Koga, K.T., Hammouuda, T., Poitrasson, F.Trace element partitioning between carbonatitic melts and mantle transition zone minerals: implications for the source of carbonatites.Geochimica et Cosmochimica Acta, Vol. 73, 1, pp. 239-255.MantleCarbonatite
DS200912-0146
2009
Dalou, C.Dalou, C., Koga, K.T., Hammouda, T., Poitrasson, F.Trace element partitioning between carbonatitic melts and mantle transition zone minerals: implications for the source of carbonatites.Geochimica et Cosmochimica Acta, Vol. 73, 1, Jan. pp. 239-255.MantleCarbonatite
DS201212-0140
2012
Dalou, C.Dalou, C., Koga, K.T., Shimizu, N., Boulon, J., Devidal, J-L.Experimental determination of F and Cl partitioning between lherzolite and basaltic melt.Contributions to Mineralogy and Petrology, Vol. 163, 4,TechnologyLherzolite petrology
DS201801-0011
2017
Dalou, C.Dalou, C., Hirschmann, M.M., von der Handt, A., Mosenfelder, J., Armstrong, L.S.Nitrogen and carbon fractionation during core-mantle differentiation at shallow depth.Earth and Planetary Science Letters, Vol. 458, 1, pp. 141-151.Mantlecarbon

Abstract: One of the most remarkable observations regarding volatile elements in the solar system is the depletion of N in the bulk silicate Earth (BSE) relative to chondrites, leading to a particularly high and non-chondritic C:N ratio. The N depletion may reflect large-scale differentiation events such as sequestration in Earth's core or massive blow off of Earth's early atmosphere, or alternatively the characteristics of a late-added volatile-rich veneer. As the behavior of N during early planetary differentiation processes is poorly constrained, we determined together the partitioning of N and C between Fe–N–C metal alloy and two different silicate melts (a terrestrial and a martian basalt). Conditions spanned a range of fO2 from ?IW-0.4 to ?IW-3.5 at 1.2 to 3 GPa, and 1400?°C or 1600?°C, where ?IW is the logarithmic difference between experimental fO2 and that imposed by the coexistence of crystalline Fe and wüstite. N partitioning ( ) depends chiefly on fO2, decreasing from to with decreasing fO2. also decreases with increasing temperature and pressure at similar fO2, though the effect is subordinate. In contrast, C partition coefficients () show no evidence of a pressure dependence but diminish with temperature. At 1400?°C, partition coefficients increase linearly with decreasing fO2 from to At 1600?°C, however, they increase from ?IW-0.7 to ?IW-2 ( to ) and decrease from ?IW-2 to ?IW-3.3 . Enhanced C in melts at high temperatures under reduced conditions may reflect stabilization of C–H species (most likely CH4). No significant compositional dependence for either N or C partitioning is evident, perhaps owing to the comparatively similar basalts investigated. At modestly reduced conditions (?IW-0.4 to -2.2), N is more compatible in core-forming metal than in molten silicate ( ), while at more reduced conditions (?IW-2.2 to ?IW-3.5), N becomes more compatible in the magma ocean than in the metal phase. In contrast, C is highly siderophile at all conditions investigated (). Therefore, sequestration of volatiles in the core affects C more than N, and lowers the C:N ratio of the BSE. Consequently, the N depletion and the high C:N ratio of the BSE cannot be explained by core formation. Mass balance modeling suggests that core formation combined with atmosphere blow-off also cannot produce a non-metallic Earth with a C:N ratio similar to the BSE, but that the accretion of a C-rich late veneer can account for the observed high BSE C:N ratio.
DS201909-2020
2019
Dalou, C.Baudouin, C., France, L., Boulanger, M., Dalou, C., Devidal, J-L.New constraints on trace element partitioning between minerals and alkaline melts.Goldschmidt2019, 1p. AbstractGlobalalkaline rocks
DS202006-0911
2020
Dalou, C.Baudouin, C., France, L., Boulanger, M., Dalou, C., Devidal, J-L.Trace element partitioning between clinopyroxene and alkaline magmas: parametrization and role of M1 site on HREE enrichment in clinopyroxenes.Contributions to Mineralogy and Petrology, Vol. 175, 15p. PdfAfrica, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Trace element partitioning between minerals and liquids provides crucial constraints on igneous processes. We quantified trace element concentrations in clinopyroxene (Cpx) phenocrysts and their phonolite melt inclusions from the 2007-08 eruption of Oldoinyo Lengai (Tanzania), and report Cpx-melt partition coefficients (D) and corresponding partitioning equations for rare earth elements (REE) and high field strength elements (HFSE) in alkaline magmas. Heavy REE (HREE: Er, Tm, Yb, Lu) are enriched relative to middle REE in alkaline Cpx and display a specific partitioning behavior that is characteristic of alkaline systems. HFSE (Ti, Zr, Hf) and HREE have similar D values (DHf?=?0.25; DLu?=?0.4) that are significantly higher than MREE (DSm?=?0.06). High DHREE/DMREE are strongly correlated with the high values of DZr and DHf relative to the low DMREE values. In this study, REE partitioning between phonolite melt and Cpx is not consistent with standard models assuming incorporation of all REE in the Cpx M2 site, but rather highlights HREE substitution in both the M1 and M2 sites. Here we highlight the preferential incorporation of HREE in the VI-coordinated M1 site, whereas light REE and MREE remain mostly distributed in the VIII-coordinated M2 site. REE partitioning is strongly dependent on Cpx chemistry: the ideal ionic radius and HREE incorporation in the M1 site increase with increasing Fe3+ content and decrease with increasing Mg2+ and AlVI content. In our study, we focus on alkaline evolved magmas, and update existing models to obtain adequate DHREE for alkaline evolved melts. We provide equations to quantify REE and HFSE partitioning, and HREE enrichment in Cpx that are based on Cpx major element composition and temperature. We propose a new model based on the lattice strain approach that predicts HREE partitioning between Cpx and alkaline magmas. The knowledge of the melt composition or of the trace element contents is not required to obtain DREE from the new model. An improved parameterization of HFSE partitioning between Cpx and phonolite and trachy-phonolite melts is also provided herein. We discuss the potential implications of the new data on our understanding of REE deposits that are commonly associated with igneous alkaline complexes.
DS2003-0308
2003
Dalpe, C.Dalpe, C., Ballantyne, D.Diamonds profiling: a new approach for forensic application8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractGlobalDiamonds - mineralogy, legal
DS2003-0728
2003
Dalpe, C.Klemme, S., Dalpe, C.Trace element partitioning between apatite and carbonatite meltAmerican Mineralogist, Vol. 88, 4, April, pp. 639-46.GlobalCarbonatite, mineralogy
DS2003-0729
2003
Dalpe, C.Klemme, S., Dalpe, C.Trace element partitioning between apatite and carbonatite meltAmerican Mineralogist, Vol. 88, pp. 639-46.MantlePetrology, Carbonatite
DS2003-1539
2003
Dalpe, C.Zack, T., Tomascak, P.B., Rudnick, R.L., Dalpe, C., McDonough, W.F.Extremely light Li in orogenic eclogites: the role of isotope fractionation duringEarth and Planetary Science Letters, Vol. 208, 3-4, pp. 279-90.MantleEclogites
DS2003-1540
2003
Dalpe, C.Zack, T., Tomascek, P.R., Rudnick, R.L., Dalpe, C., McDonough, W.F.Extremely light Li in orogenic eclogites: the role of isotope fractionation duringEarth and Planetary Science Letters, Vol. 208, 3-4, March 30, pp.279-90.SwitzerlandSubduction - not specific to diamonds
DS200412-1018
2003
Dalpe, C.Klemme, S., Dalpe, C.Trace element partitioning between apatite and carbonatite melt.American Mineralogist, Vol. 88, pp. 639-46.MantlePetrology Carbonatite
DS200412-2194
2003
Dalpe, C.Zack, T., Tomascak, P.B., Rudnick, R.L., Dalpe, C., McDonough, W.F.Extremely light Li in orogenic eclogites: the role of isotope fractionation during dehydration in subducted oceanic crust.Earth and Planetary Science Letters, Vol. 208, 3-4, pp. 279-90.MantleEclogite
DS200412-2195
2003
Dalpe, C.Zack, T., Tomascek, P.R., Rudnick, R.L., Dalpe, C., McDonough, W.F.Extremely light Li in orogenic eclogites: the role of isotope fractionation during dehydration in subducted oceanic crust.Earth and Planetary Science Letters, Vol. 208, 3-4, March 30, pp.279-90.Europe, SwitzerlandSubduction - not specific to diamonds
DS200512-1078
2004
Dalpe, C.Teng, F.Z., McDonough, W.F., Rudnick, R.L., Dalpe, C., Tomascak, P.B., Chappell, B.W., Gao, S.Lithium isotopic composition and concentration of the upper continental crust.Geochimica et Cosmochimica Acta, Vol. 68, 20, pp. 4167-4178.MantleGeochemistry, geochronology
DS1995-1664
1995
Dalrymple, J.Schaffer, C., Dalrymple, J.Lands cape evolution in Roraima North Amazonia: Planation, paleosols andpaleoclimates.Zeit. Geomorphology, Vol. 39, No. 1, pp. 1-28.GlobalGeomorphology, Roraima
DS1995-1665
1995
Dalrymple, J.Schaffer, C., Dalrymple, J.Lands cape evolution in Roraima, North Amazonia: planation, paleosols andpaleoclimatesZeitschrift fnr Geomorphologie, Vol. 39, No. 1, pp. 1-28Guyana, Venezuela, BrazilGeomorphology, Paleoclimates
DS201708-1568
2017
Dalrymple, W.Dalrymple, W., Anand, A.Koh-i-Noor. Historyexpressbookshop.co.uk, book - cost approx. 17 lbsIndiadiamond notable, Koh-i-noor

Abstract: The first comprehensive and authoritative history of the Koh-i Noor, arguably the most celebrated and mythologised jewel in the world. On 29 March 1849, the ten-year-old Maharajah of the Punjab was ushered into the magnificent Mirrored Hall at the centre of the great Fort in Lahore. There, in a public ceremony, the frightened but dignified child handed over to the British East India Company in a formal Act of Submission to Queen Victoria not only swathes of the richest land in India, but also arguably the single most valuable object in the subcontinent: the celebrated Koh-i Noor diamond.
DS201412-0160
2014
Dalsin, M.L.Dalsin, M.L., Groat, L.A., Creighton, S., Evans, R.J.The mineralogy and geochemistry of the Wicheeda carbonatite complex, British Columbia, Canada.Ore Geology Reviews, Vol. 64, pp. 523-542.Canada, British ColumbiaCarbonatite
DS1997-0105
1997
Dalstra, H.J.Bloem, E.J.M., Dalstra, H.J., Groves, D.I.Granitoid diapirism during protracted tectonism in an Archean granitoid greenstone belt, Yilgarn BlockPrecambrian Research, Vol. 85, No. 3-4, Dec. 1, pp. 147-AustraliaTectonics, Yilgarn greenstone belt
DS1860-0224
1874
DaltonDaltonThe Mines of Chotia NagpurAsiatic Soc. Bengal Journal, Vol. 43, PP. 240-IndiaDiamond Occurrence
DS1993-0311
1993
Dalton, .A.Dalton, .A., Wood, B.J.The composition of primary carbonate melts and their evolution through wallrock reaction in the mantleEarth and Planetary Science Letters, Vol. 119, No. 4, October pp. 511-526MantleCarbonate melts, Wallrock reaction
DS200812-0256
2008
Dalton, C.A.Dalton, C.A., Ekstrom, G., Dziewonski, A.M.The global attenuation structure of the upper mantle.Journal of Geophysical Research, Vol. 113, B09303.MantleGeodynamics
DS200812-0257
2008
Dalton, C.A.Dalton, C.A., Ekstrom, G., Dziewonski, A.M.The global attenuation structure of the upper mantle.Journal of Geophysical Research, Vol. 113, B9, B09303.MantleTectonics
DS201012-0135
2010
Dalton, C.A.Dalton, C.A., Faul, U.H.The oceanic and cratonic upper mantle: clues from joint interpretation of global velocity and attenuation models.Lithos, In press available, 45p.MantleGeophysics
DS201312-0183
2013
Dalton, C.A.Dalton, C.A., Gaherty, J.B.Seismic anisotropy in the continental crust of northwestern Canada.Geophysical Journal International, Vol. 193, 1, pp. 338-348.Canada, Northwest TerritoriesGeophysics - seismics
DS201412-0162
2014
Dalton, C.A.Dalton, C.A., Langmuir, C.H., Gale, A.Report geophysical and geochemical evidence for deep temperature variations beneath mid-Ocean ridges.Science, Vol. 344, no. 6179, pp. 80-83.MantleGeophysics - seismics
DS201602-0212
2015
Dalton, C.A.Hirsch, A.C., Dalton, C.A., Ritsema, J.Constraints on shear velocity in the cratonic upper mantle from Rayleigh wave phase velocity.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 11, Nov. pp. 3982-4005.MantleGeophysics - seismic

Abstract: Seismic models provide constraints on the thermal and chemical properties of the cratonic upper mantle. Depth profiles of shear velocity from global and regional studies contain positive velocity gradients in the uppermost mantle and often lack a low-velocity zone, features that are difficult to reconcile with the temperature structures inferred from surface heat flow data and mantle-xenolith thermobarometry. Furthermore, the magnitude and shape of the velocity profiles vary between different studies, impacting the inferences drawn about mantle temperature and composition. In this study, forward modeling is used to identify the suite of one-dimensional shear-velocity profiles that are consistent with phase-velocity observations made for Rayleigh waves traversing Precambrian cratons. Two approaches to the generation of 1-D models are considered. First, depth profiles of shear velocity are predicted from thermal models of the cratonic upper mantle that correspond to a range of assumed values of mantle potential temperature, surface heat flow, and radiogenic heat production in the lithosphere. Second, shear velocity-depth profiles are randomly generated. In both cases, Rayleigh wave phase velocity is calculated from the Earth models, and acceptable models are identified on the basis of comparison to observed phase velocity. The results show that it is difficult but not impossible to find acceptable Earth models that contain a low-velocity zone in the upper mantle and that temperature structures that are consistent with constraints from mantle xenoliths yield phase-velocity predictions lower than observed. For most acceptable randomly generated Earth models, shear velocity merges with the global average at approximately 300 km.
DS201603-0385
2016
Dalton, C.A.Hirsch, A.C., Dalton, C.A., Ritsema, J.Constraints on shear velocity in the cratonic upper mantle from Rayleigh wave phase velocity.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 11, pp.MantleGeophysics - seismics
DS201712-2703
2017
Dalton, C.A.Mancinelli, N.J., Fischer, K.M., Dalton, C.A.How sharp is the cratonic lithosphere; asthenosphere transition?Geophysical Research Letters, Vol. 44, 20, pp. 10,189-10,197.Mantlecraton

Abstract: Earth's cratonic mantle lithosphere is distinguished by high seismic wave velocities that extend to depths greater than 200 km, but recent studies disagree on the magnitude and depth extent of the velocity gradient at their lower boundary. Here we analyze and model the frequency dependence of Sp waves to constrain the lithosphere-asthenosphere velocity gradient at long-lived stations on cratons in North America, Africa, Australia, and Eurasia. Beneath 33 of 44 stations, negative velocity gradients at depths greater than 150 km are less than a 2-3% velocity drop distributed over more than 80 km. In these regions the base of the typical cratonic lithosphere is gradual enough to be explained by a thermal transition. Vertically sharper lithosphere-asthenosphere transitions are permitted beneath 11 stations, but these zones are spatially intermittent. These results demonstrate that lithosphere-asthenosphere viscosity contrasts and coupling fundamentally differ between cratons and younger continents.
DS202101-0011
2020
Dalton, C.A.Fischer, K.M., Rychert, C.A., Dalton, C.A., Miller, M.S., Begheim, C., Schutt, D.L.A comparison of oceanic and continental mantle lithsophere.Physics of the Earth and Planetary Interiors, Vol. 309, 106600, 20p. PdfMantlemelting

Abstract: Over the last decade, seismological studies have shed new light on the properties of the mantle lithosphere and their physical and chemical origins. This paper synthesizes recent work to draw comparisons between oceanic and continental lithosphere, with a particular focus on isotropic velocity structure and its implications for mantle temperature and partial melt. In the oceans, many observations of scattered and reflected body waves indicate velocity contrasts whose depths follow an age-dependent trend. New modeling of fundamental mode Rayleigh waves from the Pacific ocean indicates that cooling plate models with asymptotic plate thicknesses of 85-95 km provide the best overall fits to phase velocities at periods of 25 s to 250 s. These thermal models are broadly consistent with the depths of scattered and reflected body wave observations, and with oceanic heat flow data. However, the lithosphere-asthenosphere velocity gradients for 85-95 km asymptotic plate thicknesses are too gradual to generate observable Sp phases, both at ages less than 30 Ma and at ages of 80 Ma or more. To jointly explain Rayleigh wave, scattered and reflected body waves and heat flow data, we propose that oceanic lithosphere can be characterized as a thermal boundary layer with an asymptotic thickness of 85-95 km, but that this layer contains other features, such as zones of partial melt from hydrated or carbonated asthenosphere, that enhance the lithosphere-asthenosphere velocity gradient. Beneath young continental lithosphere, surface wave constraints on lithospheric thickness are also compatible with the depths of lithosphere-asthenosphere velocity gradients implied by converted and scattered body waves. However, typical steady-state conductive models consistent with continental heat flow produce thermal and velocity gradients that are too gradual in depth to produce observed converted and scattered body waves. Unless lithospheric isotherms are concentrated in depth by mantle upwelling or convective removal, the presence of an additional factor, such as partial melt at the base of the thermal lithosphere, is needed to sharpen lithosphere-asthenosphere velocity gradients in many young continental regions. Beneath cratons, numerous body wave conversions and reflections are observed within the thick mantle lithosphere, but the velocity layering they imply appears to be laterally discontinuous. The nature of cratonic lithosphere-asthenosphere velocity gradients remains uncertain, with some studies indicating gradual transitions that are consistent with steady-state thermal models, and other studies inferring more vertically localized velocity gradients.
DS1996-0324
1996
Dalton, D.L.Dalton, D.L.Basics of mining laws and regulations #1Prospectors and Developers Association of Canada (PDAC) Short Course for Developing Country, pp. 9-20GlobalMining laws, Short course notes
DS1998-0299
1998
Dalton, D.L.Dalton, D.L.Basics of mining laws and regulations #2Prospectors and Developers Association of Canada (PDAC) Fundamentals of Exploration and Mining, pp. 25-38CanadaMineral exploration, Legal - regulations
DS201910-2253
2019
Dalton, H.Dalton, H., Giuliani, A., Phillips, D., Hergt, J., O'Brien, H.Petrographic and geochemical variations in the Kaavi-Kuopio kimberlite field, Finland: the role of mantle assimilation.Goldschmidt2019, 1p. AbstractEurope, Finlanddeposit - Kaavi-Kuopio

Abstract: Kimberlites are silica-poor, volatile-rich (CO2 ± H2O), volcanic rocks that are often described as ‘hybrid’, because their parental magmas include abundant xenocrystic (crustand mantle-derived) components. Unravelling the influence of mantle assimilation on kimberlite melt compositions represents an outstanding question of kimberlite petrology. To address this issue, we have carried out a comprehensive geochemical and petrographic investigation of nine kimberlites from the Kaavi-Kuopio field in Finland, that were emplaced on the southern margin of the Karelian Craton in the Neoproterozoic (~550-600 Ma). Olivine is the dominant mineral phase in kimberlites (~50 vol.%) with cores mainly derived from the disaggregation of mantle peridotite. In contrast, olivine rims crystallise directly from the kimberlitic melt and their Mg# (Mg/(Mg+Fe)) typically show remarkable homogeneity within and between kimberlites of a single cluster and field (e.g., Lac de Gras). The Kaavi-Kuopio kimberlites appear to represent a unique case where there is a (statistically) significant difference between the average Mg# of olivine rims in different pipes (89.9 ± 0.2 to 88.5 ± 0.3). Importantly, the Mg# of olivine rims exhibit a strong correlation with the Mg# of olivine cores. Furthermore, the compositions of olivine cores (and rims) exhibit a strong correlation with those of spinel (e.g., Mg#, TiO2 contents). These geochemical variations correlate with the modal mineralogy of the kimberlites: for example, higher abundances of monticellite and lower abundances of ilmenite are associated with higher Mg# olivine. The robust relationship between entrained and assimilated lithospheric mantle material (i.e. olivine cores) and magmatic components (i.e. olivine rims, spinel, and other groundmass minerals) suggests that assimilation of lithospheric mantle has impacted the compositions of kimberlitic melts to a greater extent than previously recognised. These new data also suggest significant variations in the composition of the mantle lithosphere beneath the Kaavi-Kuopio kimberlites, which are spaced less than 10 km apart.
DS202002-0173
2019
Dalton, H.Dalton, H., Giuliani, A., O'Brien, H., Phillips, D., Hergt, J.The role of lithospheric heterogeneity on the composition of kimberlite magmas from a single field: the case of Kaavi-Kuopio, Finland.Lithos, in press available, 61p. PdfEurope, Finlanddeposit - Kaavi-Kuopio

Abstract: Kimberlites are complex, ‘hybrid’ igneous rocks because their parental magmas entrain abundant crust- and mantle-derived components that can be readily assimilated during ascent to surface. Recent studies of olivine zonation patterns have shown compositional relationships between xenocrystic cores and magmatic rims, suggesting that kimberlite melt compositions might be controlled by assimilation of mantle material during emplacement. However, the nature and extent to which this process, as well as assimilation of crustal material, influences melt compositions within single kimberlite fields remains unclear. To address this issue, we have conducted a comprehensive geochemical and petrographic investigation of kimberlites from eight pipes in the Kaavi-Kuopio field in Finland, which were emplaced on the southern margin of the Karelian craton during the Neoproterozoic (~550-600 Ma). While magmatic olivine rims are usually homogeneous in composition within and between kimberlites of a single cluster and field (e.g., Lac de Gras), the Kaavi-Kuopio kimberlites appear to represent a unique case where there are statistically significant differences between the average Mg# of olivine rims in different pipes (89.9 ± 0.2 to 88.5 ± 0.3). Importantly, the Mg# of magmatic olivine rims exhibit a strong correlation with the Mg# of their mantle-derived xenocrystic cores. Furthermore, the compositions of olivine cores and rims exhibit a robust relationship with those of magmatic spinel (e.g., Mg#, TiO2 contents). These geochemical variations also align with the mineralogy of the kimberlites: whereby abundances of phlogopite and oxides (e.g., spinel) are negatively correlated with olivine rim Mg#. The robust relationship between entrained and assimilated lithospheric mantle material (i.e. olivine cores) and magmatic components (i.e. olivine rims, spinel, and groundmass mineral abundance), combined with numerical modelling suggests that up to 10 wt% assimilation of lithospheric mantle material has modified the compositions of the Kaavi-Kuopio kimberlites. These new data are also consistent with significant variations in the lithospheric mantle composition of the Karelian craton beneath the closely spaced (<10 km) kimberlites. Finally, in addition to mantle assimilation, formation of Si-Fe-rich mica in some of the examined kimberlites might be linked to late-stage increases in oxygen fugacity potentially enhanced by crustal contamination. This study shows for the first time that variable assimilation of mantle and crustal material can generate significant variations in kimberlites derived from seemingly similar sources.
DS202002-0174
2019
Dalton, H.Dalton, H., Giuliani, A., O'Brien, H., Phillips, D., Maas, R. Petrogenesis of a hybrid cluster of evolved kimberlites and ultramafic lamprophyres in the Kuusamo area, Finland. Kasma 45, Kasma 45 south, Kasma 47, Kalettomanpuro, Kattaisenvaara, Dike 15 and LampiJournal of Petrology, in press available, 79p. PdfEurope, Finlanddeposit - Kuusamo

Abstract: Kimberlites are often closely associated, both in time and space, with a wide variety of alkaline ultramafic rock types; yet the question of a genetic relationship between these rock types remains uncertain. One locality where these relationships can be studied within the same cluster is the Karelian craton in Finland. In this study we present the first petrographic, mineral and whole-rock geochemical results for the most recently discovered kimberlite cluster on this craton, which represents an example of the close spatial overlap of kimberlites with ultramafic lamprophyres. The Kuusamo cluster incorporates seven bodies (Kasma 45, Kasma 45 south, Kasma 47, Kalettomanpuro (KP), Kattaisenvaara (KV), Dike 15 and Lampi) distributed along a 60?km NE-SW corridor. Hypabyssal samples from KV, KP, Kasma 45 and Kasma 47 consist of altered olivine macrocrysts and microcrysts and phlogopite phenocrysts in a groundmass of perovskite, apatite, spinel, ilmenite, serpentine, and calcite. These petrographic features combined with mineral (e.g., Mg-rich ilmenite, Al-Ba-rich, Ti-Fe-poor mica) and whole-rock incompatible trace element compositions (La/Nb = 0.8 ± 0.1; Th/Nb = 0.07 ± 0.01; Nb/U = 66 ± 9) are consistent with these rocks being classified as archetypal kimberlites. These Kuusamo kimberlites are enriched in CaO and poor in MgO, which combined with the absence of chromite and paucity of olivine macrocrysts and mantle-derived xenocrysts (including diamonds), suggest derivation from differentiated magmas after crystal fractionation. Samples from Lampi share similar petrographic features, but contain mica with compositions ranging from kimberlitic (Ba-Al-rich cores) to those more typical of orangeites/lamproites (increasing Si-Fe, decreasing Al-Ti-Ba), and have higher bulk-rock SiO2 contents than the Kuusamo kimberlites. These features, combined with the occurrence of quartz and titanite in the groundmass, indicate derivation from a kimberlite magma that underwent considerable crustal contamination. This study shows that crustal contamination can modify kimberlites by introducing features typical of alkaline ultramafic rock types. Dike 15 represents a distinct carbonate-rich lithology dominated by phlogopite over olivine, with lesser amounts of titaniferous clinopyroxene and manganoan ilmenite. Phlogopite (Fe-Ti-rich) and spinel (high Fe2+/Fe2++Mg) compositions are also distinct from the other Kuusamo intrusions. The petrographic and geochemical features of Dike 15 are typical of ultramafic lamprophyres, specifically, aillikites. Rb-Sr dating of phlogopite in Dike 15 yields an age of 1178.8 ± 4.1?Ma (2s), which is considerably older than the ~750?Ma emplacement age of the Kuusamo kimberlites. This new age indicates significant temporal overlap with the Lentiira-Kuhmo-Kostomuksha olivine lamproites emplaced ~100?km to the southeast. It is suggested that asthenospheric aillikite magmas similar to Dike 15 evolved to compositions akin to the Karelian orangeites and olivine lamproites through interaction with and assimilation of MARID-like, enriched subcontinental lithospheric mantle. We conclude that the spatial coincidence of the Kuusamo kimberlites and Dike 15 is likely the result of exploitation of similar trans-lithospheric corridors.
DS202007-1142
2020
Dalton, H.Giuliani, A., Pearson, D.G., Soltys, A., Dalton, H., Phillips, D., Foley, S.F., Lim, E.Kimberlite genesis from a common primary melt modified by lithospheric mantle assimilation.Science Advances, Vol. 6, eeaz0424Mantlemelting

Abstract: Quantifying the compositional evolution of mantle-derived melts from source to surface is fundamental for constraining the nature of primary melts and deep Earth composition. Despite abundant evidence for interaction between carbonate-rich melts, including diamondiferous kimberlites, and mantle wall rocks en route to surface, the effects of this interaction on melt compositions are poorly constrained. Here, we demonstrate a robust linear correlation between the Mg/Si ratios of kimberlites and their entrained mantle components and between Mg/Fe ratios of mantle-derived olivine cores and magmatic olivine rims in kimberlites worldwide. Combined with numerical modeling, these findings indicate that kimberlite melts with highly variable composition were broadly similar before lithosphere assimilation. This implies that kimberlites worldwide originated by partial melting of compositionally similar convective mantle sources under comparable physical conditions. We conclude that mantle assimilation markedly alters the major element composition of carbonate-rich melts and is a major process in the evolution of mantle-derived magmas.
DS202008-1383
2020
Dalton, H.Dalton, H., Giuiani, A., Phillips, D., Hergt, J., Maas, R., Woodhead, J., Matchan, E., O'Brien, H.Kimberlite magmatism in Finland: distinct sources and links to the breakup of Rodinia.Goldschmidt 2020, 1p. AbstractEurope, Finlanddeposit - Kuusamo

Abstract: The Karelian Craton in Finland is host to (at least) two distinct pulses of kimberlite magmatism. Twenty kimberlite occurrences have so far been discovered on the southwest margin of the craton at Kaavi-Kuopio and seven kimberlites are located in the Kuusamo area within the core of the craton. Comprehensive radiometric age determinations (U-Pb, Ar- Ar and Rb-Sr) reveal that all kimberlite activity was restricted to the Proterozoic. The Kaavi-Kuopio field was emplaced over a protracted period from ~610 to 550 Ma and is predated by the Kuusamo cluster that represents a relatively short pulse of magmatism at ~750 to 730 Ma. The emplacement of kimberlites globally has recently been linked to supercontinent reorganisation and we propose a similar scenario for these Finnish occurrences which, at the time of kimberlite emplacement, were situated on the Baltica paleo-continent. This land mass was contiguous with Laurentia in the Proterozoic and together formed part of Rodinia. The breakup of Rodinia is considered to have commenced at ~750 Ma and initiation of the opening of the Iapetus ocean at ~615 Ma. Contemporaneous with Kaavi-Kuopio magmatism, this latter period of Neoproterozoic crustal extension also includes the emplacement of kimberlites and related rocks in areas that were linked with Baltica as part of Rodinia - West Greenland and eastern North America. Both the initial and final periods of Rodinia’s breakup have been linked to mantle upwellings from the core-mantle boundary. We suggest that kimberlite magmatism in Finland was promoted by the influx of heat from mantle upwellings and lithospheric extension associated with the demise of Rodinia. Although both magmatic episodes are potentially linked to the breakup of Rodinia, whole-rock and perovskite radiogenic isotope compositions for the Kuusamo kimberlites (eNd(i) +2.6 to +3.3, eHf(i) +3.1 to +5.6) are distinct from the Kaavi-Kuopio kimberlites (eNd(i) -0.7 to +1.8, eHf(i) -6.1 to +5.2). The spread in Hf isotope compositions for the Kaavi-Kuopio magmas may be linked to variable assimilation of diverse mantle lithologies.
DS2000-0091
2000
Dalton, J.Blundy, J., Dalton, J.Experimental comparison of trace element partitioning between clinopyroxene and melt in carbonate silicate..Contributions to Mineralogy and Petrology, Vol. 139, No. 3, pp. 356-MantleMetasomatism
DS2000-0092
2000
Dalton, J.Blundy, J., Dalton, J.Experimental comparison of trace element partioning between clinopyroxene and melt in carbonate, silicate..Contributions to Mineralogy and Petrology, Vol. 139, No. 3, pp. 356-71.MantlePetrogenesis, Mantle Metasomatism
DS1993-0312
1993
Dalton, J.A.Dalton, J.A., Wood, B.J.The compositions of primary carbonate melts and their evolution through wallrock reaction in the mantle.Earth and Planetary Science Letters, Vol. 119, pp. 511-525.MantleCarbonatite
DS1993-0313
1993
Dalton, J.A.Dalton, J.A., Wood, B.J.The partioning of iron and magnesium between olivine and carbonate and the stability of carbonate under mantle conditions.Contributions to Mineralogy and Petrology, Vol. 114, pp. 501-9.MantleLherzolite, Petrology - experimental
DS1993-0314
1993
Dalton, J.A.Dalton, J.A., Wood, B.J.The partitioning of iron and magnesium between olivine and carbonate and the stability of carbonate under mantle conditions.Contributions to Mineralogy and Petrology, Vol. 114, No. 4, pp. 501-509.MantleOlivine, carbonate
DS1995-0378
1995
Dalton, J.A.Dalton, J.A., Presnall, D.C.Phase relations in system Cao MgO Al2O3 SO2 CO2 from 4.0 to 6.0 GPa-application generation of kimberlitesEos, Vol. 76, No. 46, Nov. 7. p.F697. Abstract.GlobalKimberlites, Carbonatite, Petrogenesis
DS1997-0237
1997
Dalton, J.A.Dalton, J.A., Presnall, D.C.Phase relations in the system Cao MgO Al2O3 SiO2 Co2 from 3.0 to 7.0 GPa:carbonatites, kimberlites....Geological Association of Canada (GAC) Abstracts, GlobalCarbonatite, kimberlites, related rocks
DS1998-0300
1998
Dalton, J.A.Dalton, J.A., Presnall, D.C.Carbonatitic melts along the solidus of model lherzolite in the systemCaOMgOAl2O3 SiO2 CO2 (3-7 GPa)Contributions to Mineralogy and Petrology, Vol. 131, No. 2/3, pp. 123-135.GlobalCarbonatite, Petrology - experimental
DS1998-0301
1998
Dalton, J.A.Dalton, J.A., Presnall, D.C.The continuum of primary carbonatitic kimberlitic melt composition in equilibrium with lherzolite: dat a 6 GpaJournal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 1953-64.GreenlandCarbonatite, Lherzolite - kimberlite melt, petrology, Safartoq
DS2003-0309
2003
Dalton, R.Dalton, R.Continental drilling: hot tempers, hard coreNature, No. 6953, Sept. 4, pp. 13-14.MantleDrilling
DS200412-0400
2003
Dalton, R.Dalton, R.Continental drilling: hot tempers, hard core.Nature, No. 6953, Sept. 4, pp. 13-14.MantleDrilling
DS1991-0332
1991
Daltry, V.D.C.Daltry, V.D.C.African type mineralogy: a general review (1838-1988)Journal of African Earth Sciences, Vol. 13, No. 3-4, pp. 313-322AfricaMineralization, Review
DS1993-0315
1993
Daltykov, O.G.Daltykov, O.G., Erinchek, Yu.M.Mechanism of the development of buried high pressurerominence haloes of the accessory minerals of diamond on ancient local rises.Doklady Academy of Sciences USSR, Earth Science Section, Vol. 321, No. 8, August 1993, pp. 126-132.Russia, Commonwealth of Independent States (CIS)Indicator minerals, Accessory minerals
DS1995-1911
1995
Daly, J.S.Timmerman, M.J., Daly, J.S.samarium-neodymium (Sm-Nd) evidence for late Archean crust formation in the Lapland-Kola mobilebelt, Kola Peninsula, Russia NorwayPrecambrian Research, Vol. 72, No. 1-2, March pp. 97-108.Russia, NorwayGeochronology, Crust
DS1996-0933
1996
Daly, J.S.McLelland, J., Daly, J.S., McLelland, J.M.The Grenville Orogenic cycle (ca 1350-1000Ma); an Adirondack perspectiveTectonophysics, Vol. 265, No. 1/2, Nov. 15, pp. 1-28OntarioGrenville Orogeny, Tectonics
DS2000-0199
2000
Daly, J.S.Daly, J.S., Hjelt, S.E.Geometry and evolution of the northern Fennoscandian lithosphere - the Europrobe SVEKALAPKO project.Igc 30th. Brasil, Aug. abstract only 1p.Russia, Lapland, Kola, KareliaSvecofennian Orogen, Tomography, seismics
DS201607-1338
2016
Daly, M.Daly, M., Hawkesworth, C.Tectonic influences on the development of the continental crust.IGC 35th., Session A Dynamic Earth 1 p. abstractMantleTectonics
DS201709-1997
2017
Daly, M.Hawkesworth, C., Kendall, M., Daly, M., Cawood, P., Dhuime, B.Within plate and subduction related settings in the Archean.Goldschmidt Conference, abstract 1p.Mantlesubduction

Abstract: There is much discussion of the timing of the onset of plate tectonics, yet there is increasing evidence that magma types similar to those from recent within plate and subduction related settings were generated in different areas at broadly similar times in the early Archaean. It may therefore be helpful to consider when plate tectonics became the dominant mechanism associated with the generation of continental crust, rather than just when it started. To do this we discuss the geochemical and mechanical characteristics of the lithosphere in the search to discern differences between Early Archaean and younger tectonic environments. Seismic tomography allows increasingly detailed mapping of the lithosphere, and it provides some evidence that the degree of anisotropy is different in different Archaean terrains. Structural styles also appear to vary from basin and swell, or vertical tectonics, as in the Australia Pilbara and southern Africa, to those with more strongly developed regional fabrics and greater seismic anisotropy, as in North America. These terrains tend to be characterized by inferred within-plate and subduction-related magmatism respectively, and we consider possible links between the degree of crustal and mantle anisotropy and the nature of the magmatic record. At least in some areas, terrains with stronger regional fabrics may be younger than those in which such fabrics are less well developed. A model is developed for the generation and stabilization of continental lithosphere in the Archaean. It seeks to reconcile evidence for hot shallow melting with melt fractions up to 40% to generate residual peridotites now preserved as mantle xenoliths, and the lower degrees of melting required to generate the mafic sources of TTGs (fractionated Lu/Hf and Sm/Nd, and perhaps not Rb/Sr).
DS1986-0163
1986
Daly, M.C.Daly, M.C.Crustal shear zones and thrust belts: their geometry and continuity In central Africa.Phil. Transactions Royal Society. Lond., Vol. 317A pp. 111-28.Central Africa, Tanzania, Zambia, ZaireTectonics - structure
DS1988-0153
1988
Daly, M.C.Daly, M.C.Crustal shear zones in central Africa: a kinematic approach toProterozoictectonicsEpisodes, Vol. 11, No. 1, March pp. 5-11AfricaBlank
DS201509-0416
2015
Daly, M.C.McKenzie, D., Daly, M.C., Priestley, K.The lithospheric structure of Pangea.Geology, Vol. 43, 9, pp. 783-786.MantlePangea

Abstract: Lithospheric thickness of continents, obtained from Rayleigh wave tomography, is used to make maps of the lithospheric thickness of Pangea by reconstructing the continental arrangement in the Permian. This approach assumes that lithosphere moves with the overlying continents, and therefore that the arrangement of both can be obtained using the poles of rotation obtained from magnetic anomalies and fracture zones. The resulting reconstruction shows that a contiguous arc of thick lithosphere underlay most of eastern Pangea. Beneath the western convex side of this arc, there is a wide belt of thinner lithosphere underlying what is believed to have been the active margin of Pangea, here named the Pangeides. On the inner side of this arc is another large area of thin lithosphere beneath the Pan-African belts of North Africa and Arabia. The arc of thick lithosphere is crossed by bands of slightly thinner lithosphere that lie beneath the Pan-African and Brasiliano mobile belts of South America, Africa, India, Madagascar, and Antarctica. This geometry suggests that lithospheric thickness has an important influence on continental deformation and accretion.
DS1920-0226
1925
Daly, R.A.Daly, R.A.Carbonate Dikes of the Premier Diamond Mine, TransvaalJournal of Geology, Vol. 33, PP. 659-684.South Africa, TransvaalKimberlite Mines And Deposits, Carbonatite, Related Rocks
DS2002-0652
2002
DalzielHanson, R., Pancake, J., Crowley, J., Ramezani, Bowring, Dalziel, GoseCorrelation of 1.1 GA large igneous provinces on the Laurentia and Kalahari Cratons:Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 561.South Africa, Botswana, Zimbabwe, OntarioTectonics, Gondwana
DS200612-0527
2006
DalzielHanson, R.E., Harmer, R.E., Blenkinsop, T.G., Bullen, D.S., Dalziel, Gose, Hall, Kampunzu, Key, MukwakwamiMesoproterozoic intraplate magmatism in the Kalahari Craton: a review.Journal of African Earth Sciences, Vol. 46, 1-2, pp. 141-167.Africa, South AfricaMagmatism
DS200612-0528
2006
DalzielHanson, R.E., Harmer,Blenkinsop, Bullen, Dalziel, Gose, Hall, Kampunzu, Key, Mukwakwami, Munyaniwa, Pancake, Seidel, WardMesoproterozoic intraplate magmatism in the Kalahari Craton: a review.Journal of African Earth Sciences, In press available,Africa, South AfricaAlkaline rocks, carbonatite, Premier kimberlite cluster
DS1994-0368
1994
Dalziel, I.Dalziel, I., et al.Late Precambrian tectonics and the dawn of the PhanerozoicGsa Today, Vol. 4, No. 1, January pp. 8, 9GlobalTectonics, Phanerozoic, Penrose Conference report
DS1996-0325
1996
Dalziel, I.Dalziel, I., et al.The Argentine Precordillera: a Laurentian Terrane? Brief overview of a Penrose ConferenceGsa Today, Vol. 6, No. 2, Feb. pp. 16-18ArgentinaTectonics, Laurentia
DS1991-0333
1991
Dalziel, I.W.D.Dalziel, I.W.D.Pacific margins of Laurentia and East Antarctica-Australia as a conjugate rift pair: evidence and implications for an Eocambrian supercontinentGeology, Vol. 19, No. 6, June pp. 598-601Australia, AntarcticaTectonics, Craton
DS1992-0327
1992
Dalziel, I.W.D.Dalla Salda, L.H., Dalziel, I.W.D., Cingolani, C.A., Varela, R.Did the Taconic Appalachians continue into southern South America?Geology, Vol. 20, No. 12, December pp. 1059-1062Appalachia, South America, ArgentinaTectonics, Orogeny
DS1992-0328
1992
Dalziel, I.W.D.Dalziel, I.W.D.Late Gondwanide tectonic rotations within GondwanalandTectonics, Vol. 11, No. 3, June pp. 603-607Plate tectonics
DS1992-0329
1992
Dalziel, I.W.D.Dalziel, I.W.D.Pre-Mesozoic plate tectonics: new geologic ideas await paleomagnetictestingEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 93PangeaPaleomagnetics, Plate tectonics
DS1992-0330
1992
Dalziel, I.W.D.Dalziel, I.W.D.On the origin of LaurentiaGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A115South AmericaPlate tectonics, Terranes
DS1992-0626
1992
Dalziel, I.W.D.Grunow, A.M., Dalziel, I.W.D., Harrison, T.M., Heizler, M.T.Structural geology and geochronology of subduction complexes along the margin of Gondwanaland: new dat a from the Antarctic Peninsula and southernmostAndesGeological Society of America (GSA) Bulletin, Vol. 104, No. 11, November pp. 1497-1514Andes, AntarcticaStructure, Geochronology
DS1994-0369
1994
Dalziel, I.W.D.Dalziel, I.W.D.Precambrian Scotland as a Laurentia-Gondwana link: origin and significance of cratonic promontoriesGeology, Vol. 22, No. 7, July pp. 589-592ScotlandTectonics, Gondwanaland
DS1995-0379
1995
Dalziel, I.W.D.Dalziel, I.W.D.Earth before PangeaScientific American, Vol. 272, No. 1, Jan. pp. 58-63PangeaOverview
DS1995-0380
1995
Dalziel, I.W.D.Dalziel, I.W.D., Lawver, L.A.Plumes and dynamics of supercontinental fragmentationEos, Vol. 76, No. 46, Nov. 7. p.F172. Abstract.MantlePlumes, Gondwana
DS1995-0835
1995
Dalziel, I.W.D.Hutson, F.E., Dalziel, I.W.D.Paleomagnetic dat a from neoproterozoic Watts Needle Formation ShackletonRange, Antarctica.. supercontinentGeological Society of America (GSA) Abstracts, Vol. 27, No. 6, abstract p. A 161.AntarcticaPaleomagnetism, Shackleton Range
DS1996-0326
1996
Dalziel, I.W.D.Dalziel, I.W.D., Dalla Salda, L.H.The early Paleozoic evolution of the Argentine Pre Cordillera as a Laurentian rifted, drifted terrane:Geological Society of America (GSA) Bulletin, Vol. 108, No. 3, March pp. 372-375Argentina, CordilleraGeodynamics, Collided terrane
DS1997-0238
1997
Dalziel, I.W.D.Dalziel, I.W.D.NeoProterozoic - Paleozoic geography and tectonics: review, hypothesis, environmental speculation.Geological Society of America (GSA) Bulletin., Vol. 109, No. 1, Jan. pp. 16-42.GlobalLaurentia, Gondwanaland, Tectonics
DS1997-0239
1997
Dalziel, I.W.D.Dalziel, I.W.D.Neoproterozoic -Paleozoic geography and tectonics: review, hypothesis, environmental speculationGeological Society of America (GSA) Bulletin, Vol. 109, No. 1, Jan. pp. 16-42Global, LaurentiaTectonics, Review
DS2000-0200
2000
Dalziel, I.W.D.Dalziel, I.W.D., Lawver, L.A., Murphy, J.B.Plumes, orogenesis, and supercontinental fragmentationEarth and Planetary Science Letters, Vol. 178, No. 1-2, May 15, pp. 1-12.MantleMantle plumes, Genesis - Tectonics, plate
DS2000-0201
2000
Dalziel, I.W.D.Dalziel, I.W.D., Mosher, S., Gahagan, L.M.Laurentia Kalahari collision and the assembly of RodiniaJournal of Geology, Vol. 108, pp. 499-513.GlobalCraton, Llano Orogenic belt, Namaqua, Tectonics, suture
DS2002-0965
2002
Dalziel, I.W.D.Loewy, S.L., Connelly, J.N., Dalziel, I.W.D.Pb isotopes as a correlation tool to constrain Rodinia reconstructionGeological Society of America Annual Meeting Oct. 27-30, Abstract p. 558.Scotland, Labrador, Greenland, LaurentiaGeochronology, Gondwana
DS200512-0203
2005
Dalziel, I.W.D.Dalziel, I.W.D.The setting of LIPS in the lithosphere through time: one test of the plume hypothesis.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, geothermometry
DS201911-2515
2019
Dalziel, I.W.D.Dalziel, I.W.D., Dewey, J.F.The classic Wilson Cycle revisited.IN: Cycle Concepts in Plate Tectonics, editors Wilson and Houseman , Geological Society of London special publication 470, pp. 18-38.Mantleplate tectonics

Abstract: In the first application of the developing plate tectonic theory to the pre-Pangaea world 50 years ago, attempting to explain the origin of the Paleozoic Appalachian-Caledonian orogen, J. Tuzo Wilson asked the question: ‘Did the Atlantic close and then reopen?’. This question formed the basis of the concept of the Wilson cycle: ocean basins opening and closing to form a collisional mountain chain. The accordion-like motion of the continents bordering the Atlantic envisioned by Wilson in the 1960s, with proto-Appalachian Laurentia separating from Europe and Africa during the early Paleozoic in almost exactly the same position that it subsequently returned during the late Paleozoic amalgamation of Pangaea, now seems an unlikely scenario. We integrate the Paleozoic history of the continents bordering the present day basin of the North Atlantic Ocean with that of the southern continents to develop a radically revised picture of the classic Wilson cycle The concept of ocean basins opening and closing is retained, but the process we envisage also involves thousands of kilometres of mainly dextral motion parallel with the margins of the opposing Laurentia and Gondwanaland continents, as well as complex and prolonged tectonic interaction across an often narrow ocean basin, rather than the single collision suggested by Wilson.
DS1998-0302
1998
Dam, G.Dam, G., Larsen, M., Sonderholm, M.Sedimentary response to mantle plumes: implications from Paleocene onshoresuccessions, West and East.Geology, Vol. 26, No. 3, March pp. 207-210.GreenlandPlume model, volcanism.
DS1994-0370
1994
Damarapurshad, A.K.Damarapurshad, A.K., Hart, R.J., Meyer, H.O.Geochemistry of single diamonds by instrumental neutron activationanalysis.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 24-26.Brazil, South Africa, Colorado, ChinaGeochemistry, Trace elements in diamonds
DS1995-0381
1995
Damarupursad, A.K.Damarupursad, A.K.Geochemistry of single diamonds and their inclusions by instrumental neutron activation analysis.Msc. Thesis, University Of Witwatersrand, South AfricaGeochemistry, Diamond morphology
DS1991-1610
1991
DamarupurshadSmith, C.B., Ramos, .N., Hatton, C.J., Horsch, H., DamarupurshadEclogite xenolith with exsolved sanidine from the Proterozoic Kuruman kimberlite province, northern Cape, R.S.A.Proceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 383-384South AfricaZero, geochronology, xenoliths, Eclogite xenoliths
DS1991-0677
1991
Damarupurshad, A.Hart, R.J., Damarupurshad, A., Sellschop, J.P.F., Meyer, H.O.A.The trace element analysis of single diamond crystal by neutron activationanalysisProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 163-166Colorado, Brazil, South AfricaDiamond morphology, Geochemistry, George Creek, Romaria, Finsch
DS1995-0382
1995
Damarupurshad, A.K.Damarupurshad, A.K., Hart, R.J., Smith, C.B.Distinguishing between Diamondiferous and barren kimberlitic rocks on the basis of whole rock analysis.Exploration and Mining Geology, Vol. 4, No. 1, p. 84.AustraliaGeochemistry -whole rock, Multivariant discriminate analysis
DS2000-0202
2000
Damarupurshad, A.K.Damarupurshad, A.K.South Africa's mineral industry 1999-2000. Pt. 2, Review of diamondsSouth Africa Department Min. Energy, pp. 22-26.South AfricaEconomics, production, mining, Diamonds
DS2000-0203
2000
Damarupurshad, A.K.Damarupurshad, A.K.South Africa's mineral industry 1998/99. Pt. 2, Review of diamondsSouth Africa Department Min. Energy, pp. 23-30.South AfricaEconomics, production, mining, Diamonds
DS2002-0189
2002
DamascenoBorisova, A.Y., Nikogosian, Scoates, Weis, DamascenoMelt, fluid inclusion and crystal inclusions in olivine phenocrysts - Kerguelen plume derived picritic basaltsChemical Geology, Vol.183,1-4,pp.195-220.Kerguelen IslandsLithosphere - picrites, Geochemistry
DS2001-1224
2001
Damasceno, D.Weis, D., Ingle, S., Damasceno, D., Frey, NicolaysenOrigin of continental components in Indian Ocean basalts: evidence from Elan Bank Kerguelen Plateau.Geology, Vol. 29, No. 2, Feb. pp. 147-50.Indian OceanIgneous province - plume, contamination
DS2002-1445
2002
D'Ambrosio, C.Sgrigna, V., D'Ambrosio, C., Yabovskaya, T.B.Numerical modeling of preseismic slow movements crustal blocks caused by quasi-horizontal tectonic forcesPhysics of the Earth and Planetary Interiors, Vol.129, 3-4, pp.313-24.MantleTectonics
DS200512-0716
2005
D'Amelio, F.Melluso, L., Morra, V., Bortsu, P., Tommasini, S., Renna, MR, Duncan, R., Franciosi, L., D'Amelio, F.Geochronology and petrogenesis of the Cretaceous Antampombato Ambatovy Complex and associated dyke swarm, Madagascar.Journal of Petrology, Vol. 46, 10, pp. 1963-1996.Africa, MadagascarGeochronology - dike
DS201212-0212
2012
Damm, V.Funck, T., Gohl, K., Damm, V., Heyde, I.Tectonic evolution of southern Baffin Bay and Davis Strait: results from a seismic refraction transect between Canada and Greenland.Journal of Geophysical Research, Vol. 117, B04107, 24p.Canada, Nunavut, Baffin Island, Europe, GreenlandGeophysics - seismics
DS201212-0711
2012
Damm, V.Suckro, S.K., Gohl, K., Funck, T., Heyde, I., Ehrardt, A., Schreckenberger, B., Gerlings, J., Damm, V., Jokat, W.The crustal structure of southern Baffin Bay: implications from a seismic refraction experiment.Geophysical Journal International, Vol. 190, 1, pp. 37-58.Canada, Nunavut, Baffin Island, Europe, GreenlandGeophysics - seismics
DS1988-0618
1988
Dammann, H.Scmitt, H., Dammann, H.Diamond as a new electronic materialNational Technical Information Service N88-29098/6, N88-29098/6/XAD, Sept. 1988, 28pGlobalReplacement for gallium arsenide, Diamond applications
DS1920-0328
1927
Dammer, B.Dammer, B., Tietze, O.Die Nutzbaren MineralienStuttgart: Enke., Vol. 1, 560P. ( DIAMOND PP. 1-62 ). XEROX.GlobalKimberley, Mineralogy, Janlib, Kimberlite
DS1960-1092
1969
Damon, P.E.Damon, P.E., Giletti, B.J.The Age of the Basement Rocks of the Colorado Plateau and Adjacent Areas.New York Academy of Sciences Annual, Vol. 91, PP. 443-453.United States, Colorado PlateauBlank
DS200612-0303
2005
Dampare, S.Dampare, S., Asiedu, D., Banoeng Yakubo, B., Shibata, T.Heavy mineral analysis of alluvial sediments from Akwatia area of the Birim Diamondiferous field, Ghana.Earth Science Report, Okayama University, Vol. 12, 1, pp. 7-14.Africa, GhanaGeochemistry
DS200412-0066
2004
Dampare, S.B.Asiedu, D.K., Dampare, S.B., Sakyi, P.A., Banoeng Yakubo, B., Osae, S., Nyarko, B.J.B., Manu, J.Geochemistry of Paleoproterozoic metasedimentary rocks from the Birim Diamondiferous field: implications for provenance and crusGeochemical Journal, Vol. 38, 3, pp. 215-228.Africa, GhanaGeochemistry - Archean Proterozoic boundary
DS200512-0204
2005
Dampare, S.B.Dampare, S.B., Asiedu, D.K., Osea, S., Nyarko, B.J.B., Banoeng-Yakubo, B.Determination of rare earth elements by neutron activation analysis in altered ultramafic rocks from the Akwatia district of Birim Diamondiferous field.Journal of Radioanalytical and Nuclear Chemistry , Vol. 265, 1, pp. 101-106.Africa, GhanaREE - Birim, Akwatia
DS201012-0021
2010
Dampare, S.B.Asiedu, D.K., Dampare, S.B., Samoah Sakyi, P., Boamah, D.Major and trace element geochemistry of kimberlitic rocks in the Akwatia area of the Birim Diamondiferous field, southwest Ghana.African Journal of Science and Technology, Science and Engineering series, Vol. 8, 2, pp. 81-91.Africa, GhanaDeposit - Akwatia
DS1981-0332
1981
Dampier mining co. ltd.Paterson, P., Dampier mining co. ltd.Tr 7748h to Tr 7752h Mt. Ramsay Diamond ExplorationWest Australia Geological Survey Open File., No. GSWA 1197 ROLL 403 M 2687, 9P.Australia, Western AustraliaProspecting, Geochemistry, Stream Sediment Sampling, Heavy Mine
DS1989-1581
1989
Damtoro, J.Ward, C.R., Damtoro, J.In-field entry of geotechnical dat a in borehole logging to a hand held portable computer systemQuart. Journal of Eng. Geol. London, Vol. 22, pp. 359-363GlobalComputer -Program, Geotechnical data
DS1983-0275
1983
Danchi.Haggerty, S.E., Smyth, J.R., Erlank, A.J., Rickard, R.S., Danchi.Lindsleyite (ba) and Mathiasite (k): Two New Chromium Titanaetes in the crichtonite Series from the Upper Mantle.American MINERALOGIST., Vol. 68, PP. 494-505.South AfricaKimberlite, Rare Earth Elements (ree), Mineral Chemistry, Analyses
DS1975-0076
1975
Danchin, K.Ferguson, J., Martin, H., Nicholson, L.O., Danchin, K.Gross Brukkaros, a Kimberlite Carbonatite VolcanoPhysics and Chemistry of the Earth., Vol. 9, PP. 219-234.Southwest Africa, NamibiaGibeon, Melilitite, Geology, Geochronology
DS1970-0680
1973
Danchin, R.Ferguson, J., Martin, H., Nicolaysen, L.O., Danchin, R.Gross Brukkaros: a Kimberlite Carbonatite Volcano1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 107-110.Southwest Africa, NamibiaGeology
DS1970-0495
1972
Danchin, R.V.Danchin, R.V., D'orey, F.Chromian Spinel Exsolution in Ilmenite from the Premier Mine,transvaal, South Africa.Contributions to Mineralogy and Petrology, Vol. 35, No. 1, PP. 43-49.South Africa, TransvaalMineralogy
DS1970-0678
1973
Danchin, R.V.Ferguson, J., Danchin, R.V., Nixon, P.H.Petrochemistry of Kimberlite AutolithsMaseru: Lesotho Nat. Dev. Corp. Lesotho Kimberlites Editor N, PP. 285-293.LesothoGeochemistry, Petrology, Xenoliths, Ilmenite, Mothae, Microprobe
DS1970-0679
1973
Danchin, R.V.Ferguson, J., Danchin, R.V., Nixon, P.H.Fenitization Associated With Kimberlite MagmasMaseru: Lesotho Nat. Dev. Corp. Lesotho Kimberlites Editor N, PP. 207-213.Lesotho, South AfricaAlteration, De Beers, Letseng la Terae, Kao
DS1970-0885
1974
Danchin, R.V.Boyd, F.R., Danchin, R.V.Discrete Nodules from the Artur de Paiva Kimberlite, AngolaCarnegie Institute Yearbook, FOR 1973, PP. 278-282.AngolaPetrography
DS1975-0057
1975
Danchin, R.V.Danchin, R.V., Ferguson, J., Mcivor, J.R., Nixon, P.H.The Composition of Late Stage Kimberlite Liquids As Revealed by Nucleated Autoliths.Physics and Chemistry of the Earth, Vol. 9, PP. 235-245.Southwest Africa, NamibiaKimberlite, Genesis
DS1975-0265
1976
Danchin, R.V.Danchin, R.V., Boyd, F.R.Ultramafic Nodules from the Premier Kimberlite Pipe, South Africa.Carnegie Institute Yearbook, FOR 1975, PP. 531-538.South AfricaPetrography
DS1975-0988
1979
Danchin, R.V.Danchin, R.V.Mineral and Bulk Chemistry of Garnet Lherzolite and Garnet Harzburgite xenoliths from the Premier Mine, South Africa.Proceedings of Second International Kimberlite Conference, Proceedings Vol. 2, PP. 104-126.South AfricaMineral Chemistry, Geochemistry
DS1980-0071
1980
Danchin, R.V.Boyd, F.R., Danchin, R.V.Lherzolites, Eclogites and Megacrysts from Some Kimberlites of Angola.American Journal of Science (JACKSON MEMORIAL VOLUME), PP. 528-549.Angola, West AfricaPetrology
DS1982-0162
1982
Danchin, R.V.Danchin, R.V., Harris, J.W., Scott smith, B.H., Stracke, K.J.Diamondiferous Kimberlites at Orroroo, South AustraliaProceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 205, (abstract.).AustraliaKimberlite, Phlogophite, Chemistry, Mineralogy, Heavy Minerals
DS1982-0550
1982
Danchin, R.V.Scott smith, B., Danchin, R.V., Harris, J.W., Stracke, K.J.Kimberlite Near Orroroo, South AustraliaStockdale Prospecting Ltd., 32P.Australia, South AustraliaKimberlite, Diamonds, Prospecting
DS1982-0551
1982
Danchin, R.V.Scott smith, B.H., Danchin, R.V., Harris, J.W., Stracke, K.J.Kimberlite Near Orroroo South AustraliaSouth Australia Open File...proceedings of Third International Kimberlite Conference., PAPER GIVEN FROM OPEN FILE E3891, 32P. 1 MAP. UNPUBL.Australia, South AustraliaDiamonds, Petrology, Heavy Minerals, Geochemistry, Geochronology
DS1982-0583
1982
Danchin, R.V.Stracke, K.J., Robinson, H.R., Arnott, F.W., Danchin, R.V., Sto.El 652 and El 853 Orroroo South Australia Progress Reports from 23rd. september 1981 to 19th. April 1982.South Australia Open File., No. E3891, 22P. UNPUBL.Australia, South AustraliaGeophysics, Geochemistry, Prospecting, Vlf, Stream Sediment Sampling
DS1983-0562
1983
Danchin, R.V.Scott smith, B.H., Danchin, R.V., Harris, J.W., Stracke, K.J.Kimberlites Near Orroroo South Australia: AppendixAnnales Scientifiques De L' Universite De Clermont-ferrand Ii, No. 74, PP. 123-126.Australia, South AustraliaAnalyses, Mineral Chemistry
DS1984-0208
1984
Danchin, R.V.Danchin, R.V.Modern Techniques in Diamond ExplorationKimberlite Occurrence And Origin A Basis For Conceptual Mode, PP. 19-20. (abstract.)GlobalTechniques, Prospecting, Mineralogy, Mineral Chemistry, Sampling
DS1984-0640
1984
Danchin, R.V.Scott smith, B.H., Danchin, R.V., Harris, J.W., Stracke, K.J.Kimberlites Near Orroroo, South AustraliaProceedings of Third International Kimberlite Conference, Vol. 1, PP. 121-142.Australia, South AustraliaPetrography, Mineralogy, Geochemistry
DS1986-0672
1986
Danchin, R.V.Robey, J.V.A., Bristowm J.W., Marxm M.R., Joyce, J., Danchin, R.V.Alkalic ultrabasic dykes of the southeast Yilgarn margin,WesternAustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 142-144AustraliaBlank
DS1987-0134
1987
Danchin, R.V.Danchin, R.V.The sub-continental Australian lithosphere- evidence from kimberlites, lamproites and other alkaline ultramafic intrusivesTerra Cognita, Conference abstracts Oceanic and Continental Lithosphere:, Vol. 7, No. 4, Autumn, abstract only p. 610TanzaniaBlank
DS1989-1284
1989
Danchin, R.V.Robey, J.V.A., Bristow, J.W., Marx, M.R., Joyce, J., Danchin, R.V.Alkaline ultrabasic dikes near Norseman, western AustraliaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 382-391AustraliaGeochronology, Lamprophyre
DS1994-0834
1994
Danchin, R.V.Janse, A.J.A., Danchin, R.V.Diamonds of western Australia: past present and futureGeological Society of Australia Abstract Volume, No. 37, pp. 194.AustraliaHistory
DS1994-0835
1994
Danchin, R.V.Janse, A.J.A., Danchin, R.V.Diamonds of Western Australia - past, present and futureGeological Society of Australia Abstracts, No. 37, p. 194.Australia, Western AustraliaBrief overview
DS200912-0147
2009
Danderfer, A.Danderfer, A., De Waele, B., Pedeira, A.J., Nalini, H.A.New geochronological constraints on the geological evolution of Espinhaco basin within the San Francisco Craton- Brazil.Precambrian Research, Vol. 170, 1-2, pp. 116-128.South America, BrazilGeochronology - not specific to diamonds
DS201710-2223
2017
Danelian, T.Danelian, T., Jolivet, M., Ionov, D.Insights into the geology and paleontology of Siberia from French-Siberian collaboration in the Earth Sciences.Bulletin de la Societe Geologique de France *eng, Vol. 188, 1-2, 7p.Russia, Siberiadeposit - Udachnaya
DS2001-0224
2001
Danesi, S.Danesi, S., Morelli, A.Structure of the upper mantle under the Antarctic plate from surface wave tomographyGeophysical Research Letters, Vol. 28, No. 23, Dec. pp. 4395-8.Mantle, AntarcticaTomography
DS1992-0331
1992
Danforth, W.W.Danforth, W.W.Digital shoreline mapping system user's guide version 1.0United States Geological Survey (USGS) Open File, No. 92-0240, 33p. $ 5.00GlobalComputer, Program -DSMS
DS202001-0017
2019
Dang, Z.Huang, C., Zhang, N, Li, Z.X., Dang, Z.Modeling the inception of supercontinent breakup: stress state and the importance of orogens.Geochemistry, Geophysics, Geosystems, in press available pdf 20p.Globalgeodynamics

Abstract: The relative significance of various geodynamic mechanisms that drive supercontinent breakup is unclear. A previous analysis of extensional stress during supercontinent breakup demonstrated the importance of the plume-push force relative to the dragging force of subduction retreat. Here, we extend the analysis to basal traction (shear stress) and cross-lithosphere integrations of both extensional and shear stresses, aiming to understand more clearly the relevant importance of these mechanisms in supercontinent breakup. More importantly, we evaluate the effect of preexisting orogens (mobile belts) in the lithosphere on supercontinent breakup process. Our analysis suggests that a homogeneous supercontinent has extensional stress of 20-50 MPa in its interior (<40° from the central point). When orogens are introduced, the extensional stress in the continents focuses on the top 80-km of the lithosphere with an average magnitude of ~160 MPa, whereas at the margin of the supercontinent the extensional stress is 5-50 MPa. In both homogeneous and orogeny-embedded cases, the subsupercontinent mantle upwellings act as the controlling factor on the normal stress field in the supercontinent interior. Compared with the extensional stress, shear stress at the bottom of the supercontinent is 1-2 order of magnitude smaller (0-5 MPa). In our two end-member models, the breakup of a supercontinent with orogens can be achieved after the first extensional stress surge, whereas for a hypothetical supercontinent without orogens it starts with more diffused local thinning of the continental lithospheric before the breakup, suggesting that weak orogens play a critical role in the dispersal of supercontinents.
DS202001-0051
2018
Dang, Z.Zhang, N., Dang, Z., Huang, C., Li, Z-X.The dominant driving force for supercontinent breakup: plume push or subduction retreat?Geoscience Frontiers, Vol. 9, pp. 997-1007.Mantlesubduction

Abstract: Understanding the dominant force responsible for supercontinent breakup is crucial for establishing Earth's geodynamic evolution that includes supercontinent cycles and plate tectonics. Conventionally, two forces have been considered: the push by mantle plumes from the sub-continental mantle which is called the active force for breakup, and the dragging force from oceanic subduction retreat which is called the passive force for breakup. However, the relative importance of these two forces is unclear. Here we model the supercontinent breakup coupled with global mantle convection in order to address this question. Our global model features a spherical harmonic degree-2 structure, which includes a major subduction girdle and two large upwelling (superplume) systems. Based on this global mantle structure, we examine the distribution of extensional stress applied to the supercontinent by both sub-supercontinent mantle upwellings and subduction retreat at the supercontinent peripheral. Our results show that: (1) at the center half of the supercontinent, plume push stress is ~3 times larger than the stress induced by subduction retreat; (2) an average hot anomaly of no higher than 50 K beneath the supercontinent can produce a push force strong enough to cause the initialization of supercontinent breakup; (3) the extensional stress induced by subduction retreat concentrates on a ~600 km wide zone on the boundary of the supercontinent, but has far less impact to the interior of the supercontinent. We therefore conclude that although circum-supercontinent subduction retreat assists supercontinent breakup, sub-supercontinent mantle upwelling is the essential force.
DS201602-0199
2016
D'Angelo, L.D'Angelo, L.The art of governing contingency: rethinking the colonial history of diamond mining in Sierra Leone.Historical Research, Vol. 89, 243, pp. 136-157.Africa, Sierra LeoneHistory

Abstract: This article briefly outlines the history of the colonial diamond industry of Sierra Leone from 1930 to 1961, highlighting its contingent aspects and the bonds guiding the decisions and actions taken by local social actors in different contexts and at different times. By drawing on colonial documents and memoirs of colonial officers, it shows how the colonial government of Sierra Leone and the mining company that exercised a monopoly on diamond extraction collaborated on the establishment of a series of legislative and disciplinary devices that encompassed forms of biopolitical expertise.
DS201603-0370
2016
D'Angelo, L.D'Angelo, L.The art of governing contingency: rethinking the colonial history of diamond mining in Sierra Leone.Historical Research, Vol. 89, no 243, pp. 136-157.Africa, Sierra LeoneHistory

Abstract: This article briefly outlines the history of the colonial diamond industry of Sierra Leone from 1930 to 1961, highlighting its contingent aspects and the bonds guiding the decisions and actions taken by local social actors in different contexts and at different times. By drawing on colonial documents and memoirs of colonial officers, it shows how the colonial government of Sierra Leone and the mining company that exercised a monopoly on diamond extraction collaborated on the establishment of a series of legislative and disciplinary devices that encompassed forms of biopolitical expertise.
DS201810-2336
2018
Danguene, P.Y.E.Kankeu, B., Greiling, R.O., Nzenti, J.P., Ganno, S., Danguene, P.Y.E., Basshahak, J., Hell, J.V.Contrasting Pan-African structural styles at the NW margin of the Congo shield in Cameroon.Journal of African Earth Sciences, Vol. 146, pp. 28-47.Africa, Camerooncraton

Abstract: Field, microstructural, and anisotropy of magnetic susceptibility (AMS, magnetic fabrics) studies assessed the Pan-African deformational history and strain geometry at the southern margin of the Central African Fold Belt (CAFB) against the older, cratonic basement of the Congo Shield (CS). Reflected light microscopy and thermomagnetic studies supported the identification of magnetic minerals. Data cover a low angle thrust margin (Mbengis-Sangmelima area) in the east and high angle shear zones cutting the margin (Kribi area) in the west, at the Atlantic coast. In the CS basement units, magnetic anisotropy is generally higher than in the low grade Pan-African units. In the latter, early D1/D2 shortening produced a flat-lying magnetic foliation parallel with the regional trend of the belt, a shallow magnetic lineation, and mostly oblate fabrics. Subsequent D3 deformation is only of local importance in the Mbengis-Sangmelima area. The magnetic lineation shows distinct maxima in NNE-SSW direction, parallel with the low angle tectonic transport direction. In the Kribi area, the NNE-SSW trending Kribi-Campo shear zone (KCSZ) affected both older rocks and Pan-African high grade metapelites of the Yaoundé unit together with their basal thrust. The early planar fabric (S1) was overprinted during D2 folding under relatively high T conditions, and subsequent D3 wrenching. Magnetic fabrics document a progressive change from oblate towards prolate ellipsoids towards the KCSZ. Magnetic foliations with medium to steep dips curve into the N-S to NE-SW orientation of the KCSZ, lineations follow the same trend with shallow to medium plunges. This fabric implies that the KCSZ is a Pan-African strike-slip shear zone with a subordinate component of compression. Strike-slip tectonics in the west (KCSZ) and thrusting in the east imply N-S to NE-SW convergence during Pan-African terrane assembly against the present northern margin of the CS. In addition, the KCSZ may separate the CS from the São Francisco Craton in Brazil and thus be the northern part of a link connecting the CAFB to the West Congo Belt in the south. This putative Pan-African link separated the São Francisco Craton from the Congo Shield prior to Mesozoic Gondwana break-up.
DS201707-1312
2017
Dani, N.Cerva-Alves, T., Remus, M.V.D., Dani, N., Basei, M.A.S.Integrated field, mineralogical and geochemical characteristics of Cacapava do sul alvikite and beforsite intrusions: a new Ediacaran carbonatite complex in southernmost Brazil.Ore Geology Reviews, in press availableSouth America, Brazilcarbonatite

Abstract: The integrated evaluation of soil geochemistry, aerogammaspectrometry (eTh), geological and structural mapping associated with the description of boreholes and outcrops in the Caçapava do Sul region, southernmost Brazil, led to the discovery of two carbonatite bodies. They are located near the eastern and southeastern border of Caçapava do Sul Granite and intrude the Passo Feio Complex. The carbonatite system is composed of early pink-colored alvikite followed by late white beforsite dikes. The carbonatites are tabular bodies concordant with the deformed host rocks. Petrographic and scanning electron microscopy show that the alvikites are dominantly composed of calcite with subordinate apatite, magnetite, ilmenite, biotite, baddeleyite, zircon, rutile, pyrochlore-like and rare earth element minerals. Beforsite is composed of dolomite and has the same minor and accessory minerals as the alvikite. U-Pb zircon geochronology via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was performed on a beforsite sample, yielding a 603.2 ± 4.5 Ma crystallization age. The carbonatite was emplaced an Ediacaran post-collisional environment with transpressive tectonism and volcanic activity marked by shoshonitic affinity.
DS202002-0177
2019
Dani, N.de Mamam Anzolin H., Dani, N., Remus, M.V.D., da Rocha Ribeiro, R., Nunes, A.R., Ruppel, K.M.V.Apatite multi-generations in the Tres Estradas carbonatite, southern Brazil: physical and chemistry meaning and implications to phosphate ore quality. Brazil Journal of Geology ( www.scielo.br) ENG, 17p. PdfSouth America, Brazildeposit - Tres Estradas

Abstract: Carbonatites were recently discovered in Southern Brazil, which increased the interest to evaluate the economic potential of these uncommon rocks, especially the Três Estradas Carbonatite. Carbonates are the dominant minerals of fresh rock followed by apatite, but the weathering process makes apatite abundant. We focused on apatite from the carbonatite using conventional petrography and electronic microscopy associated with microprobe, micro-Raman and Fourier-transform infrared spectroscopy. Results demonstrate the existence of four types. The primary type is associated with the rock crystallization and the subsequent three others are associated with weathering processes. The alteration mechanism was favorable for initial carbonate leaching and subsequent increase of phosphate with late precipitation of three new apatite generations. The deduced model involves long exposure during polycyclic climate changes, intercalating periods of warm dry with humid climate. The apatite types differ chemically and morphologically and have distinctive characteristics that are suitable to be used to differentiate them. These properties should be considered in future planes of industrial processes to transform apatite into single superphosphate, a basic input for fertilizer production.
DS1993-0785
1993
Daniel, C.G.Karlstrom, K.E., Daniel, C.G.Restoration of Laramide right lateral strike slip in northern New Mexico by using Proterozoic piercing points: tectonic implications from theProterozoic...Geology, Vol. 23, No. 12, December pp. 1139-1142.Colorado PlateauTectonics
DS2001-0225
2001
Daniel, I.Daniel, I., Cardon, H., Fiquet, G., Guyot, F., MezouarEquation of state of Aluminum bearing perovskite to lower mantle pressure conditionsGeophysical Research Letters, Vol. 28, No. 19, Oct. 1, pp. 3789-92.MantlePerovskite
DS2003-1067
2003
Daniel, I.Perrilat, J.P., Daniel, I., Lardeaux, J.M., Cardon, H.Kinetics of the coesite quartz transition: application to the exhumation of ultrahighJournal of Petrology, Vol. 44, 4, pp. 773-88.GlobalUHP
DS200412-1529
2003
Daniel, I.Perrilat, J.P., Daniel, I., Lardeaux, J.M., Cardon, H.Kinetics of the coesite quartz transition: application to the exhumation of ultrahigh pressure rocks.Journal of Petrology, Vol. 44, 4, pp. 773-88.TechnologyUHP
DS200412-1530
2004
Daniel, I.Perrillat, J.P., Ricolleau, A., Daniel, I., Fiquet, G., Mezouar, M., Cardon, H.Phase transformations of MORB in the lower mantle.Lithos, ABSTRACTS only, Vol. 73, p. S87. abstractMantleSubduction
DS200412-1664
2004
Daniel, I.Ricolleau, A., Perrillat, J.P., Fiquet, G., Menguy, N., Daniel, I., Addad, A., Vanni, C.The fate of subducted basaltic crust in the Earth's lower mantle: an experimental petrological study.Lithos, ABSTRACTS only, Vol. 73, p. S93. abstractMantleSubduction
DS200612-1077
2006
Daniel, I.Perrillat, J.P., Ricolleau, A., Daniel, I., Fiquet, G., Mezouar, M., Guignot, N., Cardon, H.Phase transformations of subducted basaltic crust in the upmost lower mantle.Physics of the Earth and Planetary Interiors, Vol. 157, 1-2, pp. 139-149.MantleUHP, subduction
DS200812-0955
2008
Daniel, I.Reynard, B., Hilairet, N., Daniel, I., Wang, Y.Rheology of serpentines, seismicity and mass transfer in subduction zone.Goldschmidt Conference 2008, Abstract p.A789.MantleSubduction
DS201602-0229
2016
Daniel, I.Perrillat, J.P., Chollet, M., Durand, S., van de Moortele, B., Chambat, F., Mezouar, M., Daniel, I.Kinetics of the olivine-ring woodite transformation and seismic attentuation in the Earth's mantle transition zone.Earth and Planetary Science Letters, Vol. 433, pp. 360-369.MantleGeophysics - seismics

Abstract: In regions of the mantle where multi-phases coexist like at the olivine-wadsleyite-ringwoodite transitions, the stress induced by the seismic waves may drive a mineralogical reaction between the low to high pressure phases, a possible source of dissipation. In such a situation, the amount of attenuation critically depends on the timescale for the phase transformations to reach equilibrium relative to the period of the seismic wave. Here we report synchrotron-based measurements of the kinetics of the olivine to ringwoodite transformation at pressure-temperature conditions of the co-stability loop, for iron-rich olivine compositions. Both microstructural and kinetic data suggest that the transformation rates are controlled by growth processes after the early saturation of nucleation sites along olivine grain boundaries. Transformation-time data show an increase of reaction rates with temperature and iron content, and have been fitted to a rate equation for interface-controlled transformation: G=k0·T·exp?[n·XFa]·exp?[-(?Ha+PV?)/RT]×[1-exp?(?Gr/RT)]G=k0·T·exp?[n·XFa]·exp?[-(?Ha+PV?)/RT]×[1-exp?(?Gr/RT)], where XFaXFa is the fayalite fraction, the exponential factor n=9.7n=9.7, View the MathML sourceln?k0=-9.1 ms-1. View the MathML sourceXFa-1 and ?Ha=199 kJ/mol?Ha=199 kJ/mol, assuming V?=0 cm3/molV?=0 cm3/mol. Including these new kinetic results in a micro-mechanical model of a two-phase loop (Ricard et al., 2009), we predict View the MathML sourceQK-1 and View the MathML sourceQµ-1 significantly higher than the PREM values for both body waves and normal modes. This attests that the olivine-wadsleyite transition can significantly contribute to the attenuation of the Earth's mantle transition zone.
DS2003-0096
2003
Daniel, J.M.Bellashen, N., Faccenna, C., Funiciello, F., Daniel, J.M., Jolivet, L.Why did Arabia separate from Africa? Insights from 3-D laboratory experimentsEarth and Planetary Science Letters, Vol. 216, 3, pp. 365-81.AfricaTectonics, rifting
DS200412-0131
2003
Daniel, J.M.Bellashen, N., Faccenna, C., Funiciello, F., Daniel, J.M., Jolivet, L.Why did Arabia separate from Africa? Insights from 3-D laboratory experiments.Earth and Planetary Science Letters, Vol. 216, 3, pp. 365-81.AfricaTectonics, rifting
DS201605-0824
2016
Daniel, M.J.Daniel, M.J., Bellingan, P., Rauscher, M.The modelling of scrubbers and AG mills in the diamond industry and when to use them.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 167-186.TechnologyMining - applied
DS201609-1714
2010
Daniel, M.J.Daniel, M.J., Morley, C.Can diamonds go all the way with HPGRs? High pressure grinding rolls.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 14p.TechnologyCrushing

Abstract: The diamond industry is no newcomer to High Pressure Grinding Rolls (HPGR) as it has used the technology for more than 20 years, predominantly in secondary crushing and recrushing roles. In fact it could be argued that the diamond industry has led the way for the wider minerals industry to consider its application. In existing conventional secondary cone crushing applications, large valuable diamonds are "won" through meticulously managing the recovery process within defined particle size ranges. COllventional crushers operate with relatively large closed side sehings, hut have the potential to damage diamonds by making direct contact with the sides of the crusher. Cone crushers also result in steep product size distributions that run a high risk of losing many of the smaller, un-liberated but more abundant diamonds from the rock. This current comminution paradigm of particle size reduction management results in recrushing processing applications or plants where HPGRs are often used. HPGRs operate under the seemingly odd condition where the gap between the rolls is largely a function of the roll diameter irrespective of the feed size. This otTern an opportun'ity for the diamond industry to consider using multiple HPGRs or units with high circulating loads to effectively generate a product with a very high proportion of fine material that can be rejected ahead of the beneficiation step. This in effect results in a new paradigm, a single comminution step, where all diamonds of all sizes are liberated and preserved. The circuit product size distribution will consist mainly of barren kimberlitic fines along with some grits, pebbJes, indicator minerals, as well as the prized lUldamaged diamonds. The HPGR product stream needs to be scrubbed, slurried and screened at t mm resulting in a greatly reduced volume of -diamond-rich particles that progress to the dense medium concentration and/or direct x-ray separation steps_ In this application, the HPGR is viewed "outside the box", but within the context of diamond winning processes. Examples of how "HPGR can go all the way" are presented in the paper. Page
DS1950-0464
1959
Daniel, R.Daniel, R.Discussion of a Paper by S.w. Devlin Entitled Mining Procedure and Method at C.d.m.South African Institute of Mining and Metallurgy. Journal, Vol. 59, No. 6, PP. 333-334.South Africa, Cape Province, Kimberley Area, Southwest AfricaKimberlite Mining, Methods, Recovery
DS200412-0401
2003
Daniel, S.E.Daniel, S.E.Environmental due diligence for exploration managers.Canadian Institute of Mining and Metallurgy Bulletin, Vol. 96, 1074, Oct. pp. 87-89.TechnologyEnvironmental
DS200612-0304
2006
Daniel, S.E.Daniel, S.E.Liability and developability: mining environmental due diligence.Insight Mining Business and Investment Forum, Held June 5-6, Toronto, 7p. text and 22p. Xerox of slidesCanadaEnvironment - not specific to diamonds
DS200912-0148
2009
Daniel de Liz, J.Daniel de Liz, J., Stoll Nardi, L.V., Fernandes de Lima, E., Jarvis, K.The trace element record in zircon from the Lavras do Sul shoshonitic association, southernmost Brazil.The Canadian Mineralogist, Vol. 47, 4, August pp. 833-846.South America, BrazilShoshonite
DS1995-1000
1995
DanielsKopylova, M.G., Rickard, R.S., Kleyenstueber, DanielsThe first finding of chromium-Sr Loparite type and chromium Chevkinite type minerals indiamonds.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 292-294.ZimbabweDiamond inclusions, Deposit -River Ranch
DS1997-0617
1997
DanielsKopylova, M.G., Rickard, P.S., Kleyenstueber, Taylor, Gurney, DanielsFirst occurrence of strontian K-chromium-loparite and chromium- chevkinite indiamonds.Russian Geology and Geophysics, Vol. 38, No. 2, pp. 405-420.ZimbabweDiamond inclusions, Deposit - River Ranch
DS2002-1456
2002
DanielsShearer, S., Bankey, Hill, Finn, Daniels, Snyder, RobertsUnited States aeromagnetic database: a companion to the North American magnetic anomaly map.Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 387.United States, CanadaMap - magnetic
DS201112-0007
2011
Daniels, A.Agnew, J., Daniels, A.Safe by accident. BooksafeByaccident.com, $ 21.95 USGlobalBook - on safety for mining industry
DS200812-1082
2008
Daniels, D.Smart, K.A., Heaman, L.M., Chocko, T., Simonetti, A., Kopylova, M., Mah, D., Daniels, D.The origin of diamond rich high MGO eclogite xenoliths from the Jericho kimberlite, Nunavut.Northwest Territories Geoscience Office, p. 56-57. abstractCanada, NunavutDeposit - Jericho
DS200912-0701
2009
Daniels, D.Smart, K.A., Heaman, L.M., Chacko, T., Simonetti, A., Kopylova, M., Mah, D., Daniels, D.The origin of hig MgO diamond eclogites from the Jericho kimberlite, Canada.Earth and Planetary Science Letters, Vol. 284, 3-4, pp. 527-537.Canada, NunavutDeposit - Jericho
DS1997-0159
1997
Daniels, D.L.Cannon, W.F., Daniels, D.L., Snyder, S.L.New aeromagnetic map of the Midcontinent rift in northwestern Wisconsin and adjacent Minnesota.Geological Society of America (GSA) Abstracts, Vol. 29, No. 4, Apr. p. 9.Wisconsin, MinnesotaGeophysics - aeromagnetics, Tectonics
DS2002-0348
2002
Daniels, D.L.Daniels, D.L., Snyder, S.L.Wisconsin aeromagnetic and gravity maps and data: a web site for distribution of dataU.s. Geological Survey, OF 02-0230 58p. http://pubs.usgs.gov/of/2002/of02-498WisconsinBlank
DS200412-0402
2002
Daniels, D.L.Daniels, D.L., Snyder, S.L.Wisconsin aeromagnetic and gravity maps and data: a web site for distribution of data.U.S. Geological Survey, OF 02-0230 58p.United States, WisconsinMap - geophysics
DS201012-0494
2010
Daniels, K.A.Menand, T., Daniels, K.A., Benghiat, P.Dyke propagation and sill formation in a compressive tectonic environment.Journal of Geophysical Research, Vol. 115, B08201 ( 12p.)MantleDikes, sills emplacement
DS1995-0383
1995
Daniels, L.Daniels, L.Botswana -Zimbabwe: Diamondiferous elephant countryProspectors and Developers Association of Canada (PDAC) Annual Meeting, p. 56-7. abstractGlobalReview
DS200412-0403
2004
Daniels, L.Daniels, L.The Daniel alluvial channel: Northern Cape, South Africa.PDAC 2004, 1p. abtract.Africa, South AfricaDiamond alluvials
DS200512-0205
2004
Daniels, L.Daniels, L.First diamond finds in Botswana.Rough Diamond Review, No. 6, Sept.pp.Africa, BotswanaHistory
DS200512-0206
2004
Daniels, L.Daniels, L.Spotlight on Botswana. Production and history of exploration.Rough Diamond Review, Dec. pp.31-35.Africa, BotswanaHistory
DS201212-0141
2012
Daniels, L.Daniels, L.Application of trace elements to global diamond exploration.PDAC 2012, abstractAfrica, southern AfricaGeochemistry
DS201412-0163
2014
Daniels, L.Daniels, L., Kufandikwame, O.The discovery of the lower mantle derived SWS-21 intrusion in the Mmadinare area of Botswana.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 10-12, POSTERAfrica, BotswanaSWS-21
DS201708-1618
2017
Daniels, L.Daniels, L.The magnitude of termites to the future of kimberlite exploration in Botswana.11th. International Kimberlite Conference, OralAfrica, Botswanatermites
DS201803-0442
2018
Daniels, L.Dira, T., Daniels, L.Contrasting termite transported indicator mineral concentrations in the Kgalafadi of central district Botswana: Macrotermes micaelseni vs Hodotermes mossambicus.Vancouver Kimberlite Cluster, March 9, 1p. AbstractAfrica, Botswanatermite and indiactor minerals
DS201808-1741
2018
Daniels, L.Dira, T., Daniels, L.The role of Hodtermes mossambicus termites and background kimberlite indicators in the Kgalagadi. PresentationSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., 38 ppts.Africa, Botswanaindicator minerals
DS201808-1740
2018
Daniels, L. R.M.Dira, T. A., Daniels, L. R.M. The significance of termites on the future of kimberlite exploration in Botswana.Mineralogy and Petrology, 10.1007/s00710-018-0608-5 8p. Africa, Botswanaindicator minerals

Abstract: The majority of the diamond mines in Botswana were discovered as a direct consequence of soil sampling for indicator minerals such as garnet and picroilmenite. Over the past 60 years the application of soil sampling for indicator minerals as a primary exploration tool has declined while aeromagnetic surveys have increased in popularity. The rate of kimberlite discovery in Botswana has declined significantly. The obvious magnetic kimberlites have been discovered. The future of new kimberlite discoveries is once again dependent on soil sampling for kimberlite indicator minerals. It is essential to have an in depth understanding of the transport mechanism of kimberlite indicator minerals from the kimberlite to the modern day surface of the Kalahari Formation, which is solely via termite bioturbation. Field observations indicate that the concentration of indicator minerals at surface is directly dependent on the physical characteristics and capabilities as well as behavioural patterns of the particular termite species dominant in the exploration area. The discovery of future diamond mines in Botswana will be closely associated with an in depth understanding of the relationship between size and concentration of kimberlite indicator minerals in surface soils and the seasonal behaviour, depth penetration capabilities, earthmoving efficiencies and mandible size of the dominant termite species within the exploration area. Large areas in Botswana, where kimberlite indicator minerals recovered from soil samples have been described as distal from source or background, will require re-evaluation. Without detailed termite studies the rate of discovery will continue to decline.
DS1991-0879
1991
Daniels, L.R.Kirkley, M.B., Gurney, J.J., Otter, M.L., Hill, S.J., Daniels, L.R.The application of Carbon isotope measurements to the identification of the sources of C in diamonds: a reviewApplied Geochemistry, Vol. 6, No. 5, pp. 477-494GlobalGeochronology, Carbon, diamonds
DS1980-0099
1980
Daniels, L.R.M.Daniels, L.R.M.Some Aspects of the Xenolith Suite from the Newlands Kimberlites, South Africa.Bsc. Thesis, University Cape Town., 57P.South AfricaXenoliths, Petrography
DS1982-0163
1982
Daniels, L.R.M.Daniels, L.R.M.A Layered Dunite-wehrlite- Websterite from Newlands, South Africa; Evidence for Small Scale Fractional Crystallization In the Mantle.Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 225, (abstract.).South AfricaKimberlite, Mineralogy
DS1986-0164
1986
Daniels, L.R.M.Daniels, L.R.M., Gurney, J.J.The chemistry of concentrate minerals and diamond inclusions of the Dokolwayo kimberlite, SwazilandProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 380-382GlobalDiamond morphology
DS1989-0327
1989
Daniels, L.R.M.Daniels, L.R.M., Gurney, J.J.The chemistry of the garnets, chromites and diamond inclusions of the Dokolwayo kimberlite, Kingdom ofSwazilandGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 1012-1021GlobalMineral chemistry, Diamond inclusions, Garnet
DS1989-1582
1989
Daniels, L.R.M.Waters, F.G., Erlank, A.J., Daniels, L.R.M.Contact relationships between MARID rock and metasomatised peridotite in akimberlite xenolithGeochemical Journal, Vol. 23, No. 1, pp. 11-17South AfricaMARID., Petrology
DS1989-1583
1989
Daniels, L.R.M.Waters, F.G., Erlank, A.J., Daniels, L.R.M.Contact relationships between Marid rock and metasomatized peridotite in a kimberlite xenolithGeochemical Journal, Vol. 23, No. 1, pp. 11-18South AfricaXenolith, Metasomatism
DS1991-0334
1991
Daniels, L.R.M.Daniels, L.R.M.A crystallization model for peridotitic diamond inclusion spinelsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 55-57Russia, Southern Africa, SwazilandDiamond inclusion, Garnets
DS1991-0335
1991
Daniels, L.R.M.Daniels, L.R.M., Gurney, J.J.Oxygen fugacity constraints on the southern African lithosphereContributions to Mineralogy and Petrology, Vol. 108, No. 1-2, pp. 154-161GlobalMantle, Geothermometry- oxygen fugacity
DS1991-0336
1991
Daniels, L.R.M.Daniels, L.R.M., Jennings, C.M.H., Lee, F.E., Blaine, J.L.The geology of the M1 kimberlite, southern BotswanaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 58-59BotswanaExploration, Kimberlite
DS1994-0371
1994
Daniels, L.R.M.Daniels, L.R.M., Jennings, C.M.H., Lee, J.E., Blaine, J.L., Billington, F.R.The geology of crater volcanics and sediments associated with the M1kimberlite, southwest Botswana.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 129-139.BotswanaKimberlite, Deposit -M1
DS1995-0384
1995
Daniels, L.R.M.Daniels, L.R.M., Richardson, S.H., Menzies, A.H., De BruinDiamondiferous garnet macrocrysts in the Newlands kimberlite, South Africa-rosetta stones from KaapvaalProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 121-123.South AfricaHarzburgites, Deposit -Newlands
DS1995-0998
1995
Daniels, L.R.M.Kopylova, M.G., Gurney, J.J., Daniels, L.R.M.Mineral inclusions in diamonds from the River Ranch kimberliteProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 289-291.ZimbabweDiamond inclusions, Deposit -River Ranch
DS1996-0327
1996
Daniels, L.R.M.Daniels, L.R.M., Gurney, J.J., Harte, B.A crustal mineral in a mantle diamondNature, Vol. 379, No. 6561, Jan. 11, p. 153-GlobalDiamond Morphology, Deposit -
DS1997-0616
1997
Daniels, L.R.M.Kopylova, M.G., Gurney, J.J., Daniels, L.R.M.Mineral inclusions in diamonds from the River Ranch kimberlite, ZimbabweContributions to Mineralogy and Petrology, Vol. 129, No. 4, pp. 366-384.ZimbabweDiamond inclusions, Deposit - River Ranch
DS2003-0310
2003
Daniels, L.R.M.Daniels, L.R.M.Genesis of kimberlite concentrate spinels8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractSwazilandDeposit - Dokolwayo
DS200412-0404
2003
Daniels, L.R.M.Daniels, L.R.M.Genesis of kimberlite concentrate spinels.8 IKC Program, Session 6, POSTER abstractAfrica, SwazilandMantle petrology, Dokolwayo
DS201212-0142
2012
Daniels, L.R.M.Daniels, L.R.M., De Bruin, D., Smuts, J.C.Exploration for concealed kimberlites in Botswana with trace element soil geochemistry.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, BotswanaGeochemistry - trace elements
DS201807-1488
2018
Daniels, L.R.M.Dira, T.A., Daniels, L.R.M.The role of Hodotermes mossambicus termites and background kimberlite indicators in the Kgalagadi .Malatswe areaSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 1-8.Africa, BotswanaIndicator minerals
DS1991-0240
1991
Daniels, P.A.Jr.Catacosinos, P.A., Daniels, P.A.Jr.Early sedimentary evolution of the Michigan BasinGeological Society of America (GSA) Special Publication Paper, No. 256, 250pMichiganSedimentary basin, Basin model, general - not specifically applicable
DS201702-0238
2017
Danielson, L.Righter, K., Nickodem, K., Pando, K., Danielson, L., Boujibar, A., Righter, M., Lapen, T.J.Distribution of Sb, As, Ge and in between metal and silicate during acccretion and core formation in the Earth.Geochimica et Cosmochimica Acta, Vol. 198, pp. 1-16.MantleCore chemistry

Abstract: A large number of siderophile (iron-loving) elements are also volatile, thus offering constraints on the origin of volatile elements in differentiated bodies such as Earth, Moon, Mars and Vesta. Metal-silicate partitioning data for many of these elements is lacking, making their overall mantle concentrations in these bodies difficult to model and origin difficult to distinguish between core formation and volatile depletion. To address this gap in understanding, we have undertaken systematic studies of four volatile siderophile elements - Sb, As, Ge and In - at variable temperature and variable Si content of metal. Several series were carried out at 1 GPa, and between 1500 and 1900 °C, for both C saturated and C-free conditions. The results show that temperature causes a decrease in the metal/silicate partition coefficient for all four elements. In addition, activity coefficients for each element have been determined and show a very strong dependence on Si content of Fe alloy. Si dissolved in metal significantly decreases the metal/silicate partition coefficients, at both 1600 and 1800 °C. The combination of temperature and Si content of the metal causes reduction of the metal-silicate partition coefficient to values that are close to those required for an origin of mantle As, Sb, Ge, and In concentrations by metal-silicate equilibrium processes. Combining these new results with previous studies on As, Sb, Ge, and In, allowed derivation of predictive expressions for metal/silicate partition coefficients for these elements which can then be applied to Earth. The expressions are applied to two scenarios for continuous accretion of Earth; specifically for constant and increasing fO2 during accretion. The results indicate that mantle concentrations of As, Sb, Ge, and In can be explained by metal-silicate equilibrium during an accretion scenario. The modeling is not especially sensitive to either scenario, although all element concentrations are explained better by a model with variable fO2. The specific effect of Si is important and calculations that include only S and C (and no Si) cannot reproduce the mantle As, Sb, Ge, and In concentrations. The final core composition in the variable fO2 model is 10.2% Si, 2% S, and 1.1% C (or XSi = 0.18, XS = 0.03, and XC = 0.04. These results suggest that core formation (involving a Si, S, and C-bearing metallic liquid) and accretion were the most important processes establishing many of Earth’s mantle volatile elements (indigenous), while post-core formation addition or re-equilibration (exogenous) was of secondary or minor importance.
DS200812-0258
2008
Danielson, V.Danielson, V.Rare purple diamonds add sizzle to Quebec discovery. Metalex Ventures - Fipke. Dianor - Ryder and Wawa area diamonds.Diamonds in Canada Magazine, Northern Miner, June, pp. 15-19.Canada, Quebec, OntarioDianor and Metalex projects
DS201112-0235
2011
Danielson, V.Danielson, V.Randy Turner: reflections of a diamond industry pioneer.Diamonds in Canada Magazine, Northern Miner, May pp. 5-10.Canada, Northwest TerritoriesHistory
DS1988-0202
1988
Danilchenko, N.A.Epshteyn, Ye.M., Danilchenko, N.A.A spatial genetic model of the Kovdor apatite-magnetite deposit, a carbonatite complex of the ultramafic,ijolite and carbonatite rockassociationInternational Geology Review, Vol. 30, No. 9, September pp. 981-993RussiaCarbonatite, Ijolite
DS1996-1363
1996
Danilenko, V.A.Starostenko, V.I., Danilenko, V.A., et al.A fully dynamic model of continental rifting applied to syn rift Evolution of sedimentary basinsTectonophysics, Vol. 268, No. 1-4, Dec. 31, pp. 211-220RussiaTectonics, Basin
DS1988-0154
1988
Danilenko, V.V.Danilenko, V.V.Thermodynamics of graphite to diamond transformationComb. Exploration R., Vol. 24, No. 5, Sept-Oct, pp. 633-637GlobalDiamond genesis
DS1982-0107
1982
Danilin, E.L.Bogdasarov, I.A., Danilin, E.L.Dalbykha Carbonatite MassifDoklady Academy of Sciences AKAD. NAUK SSSR., Vol. 267, No. 6, PP. 1440-1443.RussiaBlank
DS1999-0409
1999
DanilovLetnikov, F.A., Zvobkova, Sizykh, DanilovAccessory minerals from eclogites and diamond bearing rocks of the Kumdykul deposit.in RUSSIAN.Proceedings Russ. Min. Soc. *RUSS, Vol. 128, 6, pp. 16-27.RussiaEclogites, Deposit - Kumdykul
DS201502-0055
2015
Danilov, B.S.Dorogokupets, P.I., Dymshits, A.M., Sokolova, T.S., Danilov, B.S., Litasov, K.D.The equations of state of forsterite, wadsleyite, ringwoodite, akimotoite, Mg2SiO4 perovskite and post perovskite and phase diagram for the Mg2SiO4 system at pressures of up to 130 Gpa.Russian Geology and Geophysics, Vol. 56, 1-2, pp. 172-189.TechnologyPerovskite
DS201502-0095
2014
Danilov, B.S.Saveleva, V.B., Bazarova, E.P., Danilov, B.S.New finds of carbonatite like rocks in the western Baikal region.Doklady Earth Sciences, Vol. 459, 2, pp. 1483-1487.RussiaCarbonatite
DS201805-0978
2016
Danilov, B.S.Sokolova, T.S., Dorogokupets, P.I., Dymshits, A.M., Danilov, B.S., Konstantin, D.Microsoft excel spreadsheet for calculations of P-V-T relations and thermodynamic properties from equations of state of MgO, diamond and nine other metals as pressure markers in high-pressure and high-temperature experiments.Computers & Geosciences, Vol. 94, 1, pp. 162-169.TechnologyUHP

Abstract: We present Microsoft Excel spreadsheets for calculation of thermodynamic functions and P-V-T properties of MgO, diamond and 9 metals, Al, Cu, Ag, Au, Pt, Nb, Ta, Mo, and W, depending on temperature and volume or temperature and pressure. The spreadsheets include the most common pressure markers used in in situ experiments with diamond anvil cell and multianvil techniques. The calculations are based on the equation of state formalism via the Helmholtz free energy. The program was developed using Visual Basic for Applications in Microsoft Excel and is a time-efficient tool to evaluate volume, pressure and other thermodynamic functions using T-P and T-V data only as input parameters. This application is aimed to solve practical issues of high pressure experiments in geosciences and mineral physics.
DS201612-2299
2016
Danilov, K.B.Fantsuzova, V.I., Danilov, K.B.The structure of the Lomonsov volcanic pipe in the Arkangelsk diamond province from anomalies of the microseismic field.Journal of Volcanology and Seismology, Vol. 10, 5, pp. 339-346.Russia, Kola Peninsula, ArchangelDeposit- Lomonsov

Abstract: This paper presents results from a study of the Lomonosov volcanic pipe as derived from anomalies of the microseismic field. Microseismic sounding revealed that this volcanic pipe is a cone-shaped body with a small gradient of microseismic intensity motion (2 to 5 dB). Discontinuities generally show greater contrasts compared with the variations of microseismic motion in the pipe body. Comparison of the results of this microseismic sounding with other geological and geophysical data showed that the intensities of the micro-seismic field along lines that traversed the pipe reflect realistic structures of a kimberlite pipe and the host rocks. The method of microseismic sounding was used to reconstruct the deeper structure of the volcanic pipe and the host rocks down to depths greater than 2 km. We estimated the velocity contrast and the errors involved in the identification of vertical boundaries of the pipe. The volcanic pipe has a shape that is consistent with a nearly vertical source situated at a depth of a few hundred meters. This is hypothesized to be a typical occurrence for other diamond-bearing pipes as well.
DS201607-1312
2016
Danilova, Yu.V.Savelyeva, V.B., Demonterova, E.I., Danilova, Yu.V., Bazarova, E.P., Ivanov, A.V., Kamenetsky, V.S.New carbonatite complex in the western Baikal area, southern Siberian craton: mineralogy, age, geochemistry, and petrogenesis.Petrology, Vol. 24, 3, pp. 271-302.RussiaCarbonatite

Abstract: A dike -vein complex of potassic type of alkalinity recently discovered in the Baikal ledge, western Baikal area, southern Siberian craton, includes calcite and dolomite -ankerite carbonatites, silicate-bearing carbonatite, phlogopite metapicrite, and phoscorite. The most reliable 40Ar -39Ar dating of the rocks on magnesioriebeckite from alkaline metasomatite at contact with carbonatite yields a statistically significant plateau age of 1017.4 ± 3.2 Ma. The carbonatite is characterized by elevated SiO2 concentrations and is rich in K2O (K2O/Na2O ratio is 21 on average for the calcite carbonatite and 2.5 for the dolomite -ankerite carbonatite), TiO2, P2O5 (up to 9 wt %), REE (up to 3300 ppm), Nb (up to 400 ppm), Zr (up to 800 ppm), Fe, Cr, V, Ni, and Co at relatively low Sr concentrations. Both the metapicrite and the carbonatite are hundreds of times or even more enriched in Ta, Nb, K, and LREE relative to the mantle and are tens of times richer in Rb, Ba, Zr, Hf, and Ti. The high (Gd/Yb)CN ratios of the metapicrite (4.5 -11) and carbonatite (4.5 -17) testify that their source contained residual garnet, and the high K2O/Na2O ratios of the metapicrite (9 -15) and carbonatite suggest that the source also contained phlogopite. The Nd isotopic ratios of the carbonatite suggest that the mantle source of the carbonatite was mildly depleted and similar to an average OIB source. The carbonatites of various mineral composition are believed to be formed via the crystallization differentiation of ferrocarbonatite melt, which segregated from ultramafic alkaline melt.
DS201701-0029
2016
Danilova, Yu.V.Savelieva, V.B., Danilova, Yu.V., Bazarova, E.P., Ivanov, A.V., Kamenetsky, V.S.Carbonatite magmatism of the southern Siberian Craton 1 Ga ago: evidence for the beginning of breakup of Laurasia in the early Neoproterozoic.Doklady Earth Sciences, Vol. 471, 1, pp. 1140-1143.RussiaCarbonatite

Abstract: Apatite and biotite from dolomite?ankerite and calcite?dolomite carbonatite dikes emplaced into the Paleoproterozoic metamorphic rock complex in the southern part of the Siberian Craton are dated by the U-Pb (LA-ICP-MS) and 40Ar-39Ar methods, respectively. Proceeding from the lower intercept of discordia with concordia, the age of apatite from calcite?dolomite carbonatite is estimated to be 972 ± 21 Ma and that for apatite from dolomite?ankerite carbonatite, as 929 ± 37 Ma. Values derived from their upper intercept have no geological sense. The ages obtained for biotite by the 40Ar-39Ar method are 965 ± 9 and 975 ± 14 Ma. It means that the formation of carbonatites reflects the earliest phases of the Neoproterozoic stage in extension of the continental lithosphere.
DS1985-0052
1985
Danis, D.Bedard, J., Ludden, J., Danis, D.Silica Over saturated Residua Derived by Fractionation Assimilation from a Camptonitic Parental Magma in the Megantic Complex.Geological Association of Canada (GAC)., Vol. 10, P. A 3, (abstract.).Canada, Quebec, Montregian HillsPetrography
DS201212-0191
2012
Danisik, M.Evans, N.J., McInnes, B.I.A., McDonald, B., Danisik, M., Jourdan, F., Mayers, C., Thern, E., Corbett, D.Emplacement age and thermal footprint of the Diamondiferous Ellendale E9 lamproite pipe, Western Australia.Mineralium Deposita, in press availableAustraliaDeposit - Ellendale E9
DS201212-0192
2012
Danisik, M.Evans, N.J., McInnes, B.I.A., McDonald, B., Danisik, M., Jourdan, F., Mayers, C., Thern, E., Corbett, D.Emplacement age and thermal footprint of the Diamondiferous Ellendale E9 lamproite pipe, western Australia.Mineralium Deposita, in press availableAustraliaDeposit - Ellendale E9
DS201312-0252
2013
Danisik, M.Evans, N.J., McInnies, B.I.A., McDonald, B., Danisik, M., Jourdan, F., Mayers, C., Thern, E., Corbett, D.Emplacement age and thermal footprint of the Diamondiferous Ellendale E9 lamproite pipe, western Australia.Mineralium Deposita, Vol. 48, 3, pp. 413-421.AustraliaDeposit - Ellendale 9
DS201212-0455
2012
Danislk, M.McInnes, B.I.A., Evans, N.J., Jourdan, F., McDonald, B.J., Danislk, M., Mayers, C.Zircon U-TH-PB-HE double dating of North Australian diamond fields: Ellendale(WA) Seppelt ( WA) Merlin (NT).10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAustraliaDeposit - Ellendale, Seppelt, Merlin
DS201709-2009
2017
Dankhazi, Z.Kaldos, R., Guzmics, T., Vaczi, T., Berkesi, M., Dankhazi, Z., Szabo, C.3D Raman mapping of melt inclusions in Kerimasi alkaline and carbonatite rocks.Goldschmidt Conference, abstract 1p.Africa, Tanzaniadeposit - Kerimasi

Abstract: The use of confocal HR-Raman mapping opens new perspectives in studying melt inclusions. Our major goal is to show advantages of this powerful technique through case studies carried out on alkaline and carbonatite rocks of Kerimasi volcano (East African Rift). Raman spectrometry is one of the few methods that enable qualitative nondestructive analysis of both solid and fluid phases, therefore it is widely used for the identification of minerals and volatiles within melt and fluid inclusions. For better understanding of petrogenetic processes in carbonatite systems it is essential to find all mineral phases in the melt inclusions trapped in intrusive or volcanic rocks. Previous Raman spectroscopic point measurements in melt inclusions revealed the presence of daughter phases (e.g. alkali carbonates, hydrocarbonates) [1] but utilizing Raman mapping on them even provides information on their size, shape and distribution. Raman 3D mapping were applied on unheated multiphase melt inclusions of intrusive and volcanic rocks with high spatial resolution (XY plane < 1 micron) with a depth scan (Z step) as low as 0.5 micron at every XY point, parallel to the surface of the host minerals. Analysis below the surface of the host mineral is especially useful because we can avoid the loss of sensitive (e.g. water soluble) phases and contamination of the melt inclusions, moreover unexposed melt inclusions are suitable for further analytical measurements (e.g. EPMA, microthermometry). By scanning multiple layers 2D or 3D Raman images can be gained, thus we can get an insight into post entrapment crystallization processes that contribute to a more precise description of the evolution of alkaline and carbonatite rocks.
DS1900-0317
1905
Danks, A.Danks, A.Pretoria Oriental DiamondsSouth Africa Mines Commerce and Industry, Vol. 2, Feb. 4TH, P. 1050.Africa, South AfricaDiamond Mining Engineering
DS1993-0036
1993
DankwaAppiah, H. , Norman, D.I., Kuma, J.S., Nartey, R.S., DankwaSource of diamonds in the Bonsa fieldGeological Society Africa and Ghana, Proceedings 9th. International Conference, pp. 78-79.GhanaDiamond, Deposit -Bonsa field
DS2001-0890
2001
Dann, J.C.Parman, S.W., Grove, Dann, J.C.The production of Barberton komatiites in an Archean subduction zoneGeophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2513-16.South AfricaSubduction, Mantle plumes
DS200412-1504
2004
Dann, J.C.Parman, S.W., Grove, T.L., Dann, J.C., De Wit, M.J.A subduction origin for komatiites and craton lithospheric mantle.South African Journal of Geology, Vol. 107, 1/2, pp. 107-118.Africa, South AfricaSubduction
DS201506-0261
2015
Dannberg, J.Dannberg, J., Sobolev, S.V.Low-bouyancy thermochemical plumes resolve controversy of classical mantle plume concept.Nature Communications, Vol. 6, 6960 DOI: 10.1038 /ncomms7960MantleMagmatism
DS1991-0337
1991
Danni, J.C.M.Danni, J.C.M., Baecker, M.L., Ribeiro, C.C.The geology of the Catalao I carbonatite complexFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 25-30BrazilGeology, Carbonatite
DS1991-0338
1991
Danni, J.C.M.Danni, J.C.M., Botelho, N.F., Grossi Sad, J.H.Bulk and mineral chemistry of the olivine leucitite from Juana Vaz, Sacramento, Minas Gerais, BrasilProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 60-62BrazilRock chemistry, Leucitite -analyses
DS1991-0339
1991
Danni, J.C.M.Danni, J.C.M., Gapsar, J.C., Gonzaga, G.M.The Fazenda Alagoinha intrusion, Tres Ranchos, GoaisFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 31-36BrazilGeology, Kimberlitic intrusions
DS1994-0372
1994
Danni, J.C.M.Danni, J.C.M., Gaspar, J.C.Spinel garnet lherzolite and spinel lherzolite xenoliths from the northeastern border of Parana Basin.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 14-16.BrazilXenoliths, Parana Basin
DS200412-0612
2003
Danni, J.C.M.Gaspar, J.C., Araujo, A.L.N., Carlson, R.W., Sichel, S.E., Brod, J.A., Sgarbi, P.B., Danni, J.C.M.Mantle xenoliths and new constraints on the origin of alkaline ultrapotassic rocks from the Alto Paranaiba and Goias igneous pro8 IKC Program, Session 7, POSTER abstractSouth America, BrazilKimberlite petrogenesis
DS200812-0259
2008
Danoczi, J.Danoczi, J.Development of luminescent diamond simulants for x-ray recovery.Journal of South African Institute of Mining and Metallurgy, Vol. 108, 2, pp. 89=98.TechnologyDiamond processing
DS200812-0260
2008
Danoczi, J.Danoczi, J.Water requirements for the recovery of diamonds using grease technology.Journal of South African Institute of Mining and Metallurgy, Vol. 108, 2, pp. 123-129.TechnologyDiamond processing
DS200812-0261
2008
Danoczi, J.Danoczi, J.Water requirements for the recovery of diamonds using grease technology.Chemical Technology, June, pp. 28-33.TechnologyProcessing
DS200812-0262
2008
Danoczi, J.Danoczi, J., Koursaris, A.Development of luminescent diamond simulants for x-ray recovery.Journal of South African Institute of Mining and Metallurgy, Vol. 108, 2, pp. 37-45.TechnologyMineral processing
DS201212-0288
2012
Danoczi, J.Harvey, S., Read, G., DesGagnes, B., Shimell, M., Danoczi, J., Van Breugel, B., Fourie, L., Stilling, A.Utilization of olivine macrocryst grain size and abundance dat a as a proxy for diamond size and grade in pyroclastic deposits of the Orion South kimberlite Fort a la Corne, Sasakatchewan, Canada.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, SaskatchewanDeposit - Orion South
DS201605-0825
2016
Danoczi, J.Danoczi, J., Creighton, S.Microdiamond analysis - a method for estimating the size frequency distribution of the macrodiamonds.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 287-300.TechnologyMicrodiamonds
DS201709-1977
2016
Danoczi, J.Danoczi, J., Creighton, S.Microdiamond analysis - a method for estimating the size frequency distribution of the macrodiamonds.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 737-745.Technologymicrodiamond

Abstract: Estimating the size frequency distribution of the macrodiamonds on a new deposit is important for both economic reasons and for the design of the processing plant. Millions of dollars can be lost due to incorrectly sized comminution circuits. This report analyses an alternative methodology for macrodiamond grade estimation using the cumulative results from small parcels of microdiamonds and plotting them on a log-log scale. The method was first evaluated mathematically for diamond populations to assess the confidence for data extrapolation. Macrodiamond size distributions and grades were predicted using microdiamond data from three kimberlites, and the actual macrodiamond grades compared to the the predicted grades. The predicted grades were found to replicate the actual grades closely, showing that a high degree of confidence can be ascribed to the results from this method of analysis. This analysis can be used both for resource estimates and for predicting the diamond size distribution information needed for designing a new operation.
DS201807-1487
2018
Danoczi, J.E.Danoczi, J.E.The importance of grease technology in diamond recovery. Eg. CullinanSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 161-172.Globalgrease details, water
DS201808-1736
2018
Danoczi, J.E.Danoczi, J.E.The importance of grease technology in diamond recovery. CullinanSAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., 21 ppts.Africa, South Africamining
DS1990-0387
1990
Danoliv, A.P.Danoliv, A.P., Dementiyenko, A.I., Dushin, Y.P., Khristenko, A.I.Structural and mineralogical pre-conditions of mantle mineralization in Bureya MassifInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 789-791RussiaKimberlites, Pyrope
DS1970-0496
1972
Danova, K.V.Danova, K.V.Catalogue of the USSR Diamond FundMoscow:, 192P., ILLUS.RussiaKimberlite, Kimberley, Janlib, Gemology
DS1992-0332
1992
Dansereau, S.Dansereau, S.Technological change in the Canadian Mining IndustryRaw Materials Report, Vol. 8, No. 3, pp. 10-21CanadaMining, Overview of technology -impact on labour
DS1994-0373
1994
Dansereau, S.Dansereau, S.Mine migrancy in Zimbabwe and South AfricaRaw Materials Report, Vol. 10, No. 4, pp. 25-39Zimbabwe, South AfricaMining industry, Labour
DS1994-0374
1994
Dansereau, S.Dansereau, S.Mine migrancy in Zimbabwe and South AfricaRaw Materials Report, Vol. 10, No. 4, pp. 25-39.Zimbabwe, South AfricaMining -legal, system
DS200712-0214
2007
Dansereau, S.Dansereau, S.Globalization and mining labour, wages, skills and mobility.Minerals & Energy - Raw Materials Report, Vol. 21, 2, p. 8-22.GlobalMining - people
DS200812-1016
2008
DantasSchilling, M.E., Carlson, R.W., Viveira Conceicao, R., Dantas, Bertotto, KoesterRe-Os isotope contraints on subcontinental lithosphere mantle evolution of southern South America.Earth and Planetary Science Letters, Vol. 268, 1-2, April 15, pp. 89-101.South America, RodiniaGeochronology - xenoliths
DS201712-2725
2017
Dantas, E.Rossoni, M.B., Bastos Neto, A.C., Souza, V.S., Marquea, J.C., Dantas, E., Botelho, N.F., Giovannini, A.L., Pereira, V.P.U-Pb zircon geochronological investigation on the Morro dos Seis Lagos carbonatite complex and associated Nb deposit ( Amazonas, Brazil).Journal of South American Earth Sciences, Vol. 80, pp. 1-17.South America, Brazilcarbonatite

Abstract: We present results of U-Pb dating (by MC-ICP-MS) of zircons from samples that cover all of the known lithotypes in the Seis Lagos Carbonatite Complex and associated lateritic mineralization (the Morro dos Seis Lagos Nb deposit). The host rock (gneiss) yielded an age of 1828 ± 09 Ma interpreted as the crystallization time of this unit. The altered feldspar vein in the same gneiss yielded an age of 1839 ± 29 Ma. Carbonatite samples provided 3 groups of ages. The first group comprises inherited zircons with ages compatible with the gneissic host rock: 1819 ± 10 Ma (superior intercept), 1826 ± 5 Ma (concordant age), and 1812 ± 27 Ma (superior intercept), all from the Orosirian. The second and the third group of ages are from the same carbonatite sample: the superior intercept age of 1525 ± 21 Ma (MSWD ¼ 0.77) and the superior intercept age of 1328 ± 58 Ma (MSWD ¼ 1.4). The mineralogical study indicates that the ~1.3 Ga zircons have affinity with carbonatite. It is, however, a tendence rather than a well-defined result. The data allow state that the age of 1328 ± 58 Ma represents the maximum age of the carbonatite. Without the same certainty, we consider that the data suggest that this age may be the carbonatite age, whose emplacement would have been related to the evolution of the K'Mudku belt. The best age obtained in laterite samples (a superior intercept age of 1828 ± 12 Ma) is considered the age of the main source for the inherited zircons related to the gneissic host rock.
DS1997-0462
1997
Dantas, E.L.Hackspacher, P.C., Dantas, E.L., Legrand, J.M.Northwestern Over thrusting and related lateral escape during the Brasiliano Orogeny north of Patos lineamentInternational Geology Review, Vol. 39, No. 7, July, pp. 609-638.Brazil, BorboremaTectonics, Orogeny
DS2003-1077
2003
Dantas, E.L.Pimentel, M.M., Dantas, E.L., Fuck, R.A., Armstrong, R.A.Shrimp and conventional U Pb age, Sm Nd isotopic characteristics and tectonicAnais Academia Brasileira de Ciencias, Vol. 75, 1, pp. 97-108.Brazil, GoiasGeochronology, Alkaline rocks
DS200412-0405
2004
Dantas, E.L.Dantas, E.L., Van Schmus, W.R., Hackspacher, P.C., Fetter, A.H., De Brito Neves, B.B., Cordani, U., Nutman, A.The 3.4 3.5 Ga Sao Jose do Campestre Massif, NE Brazil: remnants of the oldest crust in South America.Precambrian Research, Vol. 130, 1-4, April 20, pp. 113-137.South America, BrazilGeochronology, Borborema
DS200412-1548
2003
Dantas, E.L.Pimentel, M.M., Dantas, E.L., Fuck, R.A., Armstrong, R.A.Shrimp and conventional U Pb age, Sm Nd isotopic characteristics and tectonic significance of the K rich Itapuranga Suite in GoiAnais Academia Brasileira de Ciencias, Vol. 75, 1, pp. 97-108.South America, Brazil, GoiasGeochronology Alkaline rocks
DS200812-0077
2008
Dantas, E.L.Barbosa, E.S.R., Junqueira-Brod, T.C., Brod, J.A., Dantas, E.L.Petrology of bebdourites from the Salitre phoscorite carbonatite complex, Brazil.9IKC.com, 3p. extended abstractSouth America, BrazilCarbonatite
DS200912-0666
2009
Dantas, E.L.Sarava dos Santos, T.J., Garcia, M.M., Amarai, W.S., Caby, R., Wernick, E., Arthaud, M.H., Dantas, E.L., Santosh, M.Relics of eclogite facies assemblages in the Ceara central domain, NW Borborema Province, NE Brazil: implications for the assembly of West Gondwana.Gondwana Research, Vol. 15, 3-4, pp. 454-470.South America, BrazilTectonics
DS201012-0124
2010
Dantas, E.L.Cordeiro, P.F.O., Brod, J.A., Dantas, E.L., Barbosa, E.S.R.Mineral chemistry, isotope geochemistry and petrogenesis of niobium rich rocks from the Catalao I carbonatite phoscorite complex, central Brazil.Lithos, Vol. 118, pp. 223-237.South America, BrazilCarbonatite
DS201012-0144
2010
Dantas, E.L.De Oliveira Cordeiro, P.F., Brod, J.A., Ventura Santos, R., Dantas, E.L., Gouvieia de Oliveira, C., Soares Rocha, Barbosa, E.Stable ( C,O) and radiogenic (Sr, Nd) isotopes of carbonates as indicators of magmatic and post magmatic processes of phoscorite series rocks and carbonatites fContributions to Mineralogy and Petrology, In press available, 14p.South America, BrazilCatalao I
DS201112-0257
2011
Dantas, E.L.De Oliveire Cordeiro, P.F., Brod, J.A., Ventura Santos, R., Dantas, E.L., Gouveia de Oliveira, C., Soares Rochas Barbosa, E.Stable (C,O) and radiogenic (Sr,Nd) isotopes of carbonates as indicators of magmatic and post-magmatic processes of phoscorite series rocks and carbonatites from Catalao 1, central Brazil.Contributions to Mineralogy and Petrology, Vol. 161, 3, pp. 451-464.South America, BrazilCarbonatite
DS201212-0053
2012
Dantas, E.L.Barbosa, E.S.R., Brod, J.A., Junqueira-Brod, T.C., Cordeiro, P.F.O., Santos, R.V., Dantas, E.L.Phoscorites from the Salitre alkaline complex, Brazil: origin and petrogenetic implications.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Salitre
DS201212-0054
2012
Dantas, E.L.Barbosa, E.S.R., Brod, J.A., Junqueira-Brod, T.C., Cordeiro, P.F.O.,Dantas, E.L., Santos, R.V.Mineralogy and petrology of the Salitre 1 phoscorite carbonatite alkaline compelx, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Slitre 1
DS201212-0681
2012
Dantas, E.L.Soares Rocha Barbosa, E., Brod, J.A., Junqueira-Brod, T.C., Dantas, E.L., De Oliveira Cordeiro, P.F., Siqueira Gomide, C.Bebdourite from its type area Sailtre 1 complex: a key petrogenetic series in the Late-Cretaceous Alto Paranaiba kamafugite carbonatite phoscorite association, central Brazil.Lithos, Vol. 146-147, pp. 56-72.South America, BrazilCarbonatite
DS201212-0770
2012
Dantas, E.L.Weska, R.K., Brod, J.A., Dantas, E.L., Araujo, D.P.Mineral chemistry of garnets and ilmenites of the Pepper-1 and Cosmos-3 intrusions, Espigao D'Oeste, Rondonia, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, Brazil, RondoniaDeposit - Pepper, Cosmos
DS201509-0426
2015
Dantas, E.L.Saraiva dos Santos, T.J., Da Silva Amaral, W., Ancelmi, M.F., Pitarello, M.Z., Fuck, R.A., Dantas, E.L.U-Pb age of coesite bearing eclogite from NW Borborema Province, NE Brazil: implications for western Gondwana assembly.Gondwana Research, Vol. 28, pp. 1183-1196.South America, BrazilUHP

Abstract: The Late Neoproterozoic assembly of western Gondwana played an important role in the subduction of oceanic and continental lithospheres. Such event was also a source of arc magmatism, reworking of cratonic margins and development of ultra-high pressure (UHP) suture zones. In the Borborema province, NE Brazil, we have described for the first time UHP rocks enclosed within gneiss migmatite and calc-silicate rocks. They bear coesite included in atoll-type garnet from metamafic rocks, identified by petrographic study and Raman microspectroscopy analysis. U-Pb zircon dating of the leucosome of the migmatites and the calc-silicate rock displays, concordant ages of 639 ± 10 Ma and 649.7 ± 5 Ma, respectively, here interpreted as the minimum age of the eclogitization event in the region. U-Pb zircon dating of the coesite-bearing rock defined a concordia age of 614. 9 ± 7.9 Ma that comprised the retrograde eclogitic conditions to amphibolite facies. The UHP rocks, mostly retrograded to garnet amphibolites, occur enclosed in the Paleoproterozoic continental block composed of calc-silicate rocks, migmatized sillimanite gneiss, mylonitic augen gneiss and granitic and tonalitic gneiss along a narrow N-S oriented belt between the Santa Quitéria magmatic arc and the Transbrasiliano lineament. This block was involved in the subduction to UHP eclogite depths, and was retrogressed to amphibolite during its exhumation and thrusting. Our data indicate an important Neoproterozoic transcontinental suture zone connecting the Pharusian belt with Borborema Province, and probably with the Brasília belt in central Brazil.
DS201702-0209
2017
Dantas, E.L.De Oliveira, I.L., Brod, J.A., Cordeiro, P.F.O., Dantas, E.L., Mancini, L.H.Insights into the Late stage differentiation processes of the Cat alao I Carbonatite complex in Brazil: new Sr-Nd and C-O isotopic dat a in minerals from niobium ores.Lithos, In press available, 44p.South America, BrazilDeposit - Catalao I

Abstract: The Late Cretaceous Catalão I carbonatite complex consists of ultramafic silicate rocks, phoscorites, nelsonites and carbonatites. The latest stages of the evolution of the complex are characterized by several nelsonite (magnetite-apatite rock) and carbonatite dykes, plugs and veins crosscutting earlier alkaline rocks. The interaction between the latter and late-stage carbonatites and/or carbo-hydrothermal fluids, converted the original dunites and bebedourites to metasomatic phlogopitites. Late-stage nelsonites (N1), pseudonelsonites (N2) and various types of dolomite carbonatites (DC) including norsethite-, magnesite- and/or monazite-bearing varieties show significant whole-rock Nd and Sr isotopic variations. To elucidate whether magmatic or metasomatic processes, or both, were responsible for these isotope variations we characterized the Nd and Sr isotope compositions of major mineral phases (i.e. apatite, dolomite, norsethite, pyrochlore and tetraferriphlogopite) in these late-stage rocks. Mineral isotope data recorded the same differences observed between N1 and N2 whole-rocks with N2 minerals showing more enriched isotopic signatures than minerals from N1. Sr isotopic disequilibrium among minerals from N2 pseudonelsonites and spatially related dolomite carbonatite pockets implies formation from batches of carbonate melts with distinct isotopic compositions. A detailed investigation of Nd and Sr isotopes from whole-rocks and minerals suggests that the most evolved rocks of the Catalão I complex probably derive from two different evolution paths. We propose that an earlier magmatic trend (path A) could be explained by several batches of immiscible and/or residual melts derived from carbonated-silicate parental magma (e.g. phlogopite picrite) contaminated with continental crust to a variable extent, in an AFCLI-like process. A second trend (path B) comprises highly variable 143Nd/144Ndi at nearly constant 87Sr/86Sri coupled with high d18O in carbonates. This is interpreted here as the result of the interaction of previously-formed dolomite carbonatites with carbo-hydrothermal fluids.
DS201809-2055
2018
Dantas, E.L.Leal, R.E., Lafon, J.M., da Ros Costa, L.T., Dantas, E.L.Orosirian magmatic episodes in the erepercuru-trombetas domain ( southeastern Guyana shield: implications for the crustal evolution of the Amazonian craton.South American Earth Sciences, Vol. 85, pp. 278-297.South America, Guyanacraton - Amazonian
DS202002-0217
2019
Dantas, E.L.Santos Santiago, J., da Silva Souza, V., Dantas, E.L., de Oliveira. C.G.Ediacaran emerald mineralization in northeastern Brazil: the case of the Fazenda Bonfim deposit.Brazil Journal of Geology ( www.scielo.br) ENG, 14p. PdfSouth America, Brazildeposit - Fazenda Bonfim

Abstract: The Fazenda Bonfim emerald deposit lies within the Seridó Belt. It is a classic example of deposit formed through metasomatic interactions between Be-rich granite intrusions and Cr(± V)-rich mafic-ultramafic rocks. The setting of the emerald mineralization was built under strong strike-slip dynamics, which produced serpentinization and talcification of mafic-ultramafic host-rocks, and was followed by syn-kinematic emplacement of Be-rich albite granite, favoring hydrothermal/metasomatic processes. The structural control and lithological-contrast were fundamental to the fluid flow and the best ore-shoot geometry, developed in the S-foliation intra-plane at the contact zone (phlogopite hornfels) between mafic-ultramafic rocks and the albite granite. Subsequently, an albitization process, linked to the final-stage of magmatic crystallization, led to an overall mineralogical and chemical change of the albite granite. 207U-235Pb data revealed inheritance ages from Archean to Neoproterozoic and a crystallization age of 561 ± 4 Ma for albite granite. However, 40Ar/39Ar data revealed plateau age of 553 ± 4 Ma for phlogopite hornfels, interpreted as the closure time for the metasomatic event responsible for the nucleation and growth of emerald crystals. The short interval of time between U-Pb and Ar-Ar data indicates an intense, but not protracted, metasomatic history, probably due to low volume of intrusive magma.
DS202005-0770
2020
Dantas, E.L.Weska, R.K., Ferreira Barbosa, P., Martins, M.V.C., Souza, V.S., Dantas, E.L.Pectolite in the Carolina kimberlitic intrusion, Espigao D'Oeste - Rondonia, Brazil. ( Pimenta Bueno field)Journal of South American Earth Sciences, Vol. 100, 10.1016/j.jsames.2020.102583 7p. PdfSouth America, Brazil, Rondoniadeposit - Carolina

Abstract: In this study, we characterize pectolite that occurs in a Carolina kimberlitic intrusion from the Pimenta Bueno Kimberlite Field (PBKF). The PBKF is the only kimberlite field of Permo-Carboniferous age in Brazil and is found on the southern Amazonian Craton. Pectolite, an Na-Ca-silicate usually identified in alkaline rocks as a primary mineral, is not common in the mineral paragenesis of kimberlites and is described here for the first time in Brazil. The genesis of pectolite in kimberlite has been well-studied and can be interpreted as a primary or secondary mineral resulting from the infiltration of an Na-rich fluid into metasomatic reactions. In the rocks from the PBKF, pectolite mainly occurs as fibrous and radial aggregates enriched in K2O that grow between olivine partially altered to serpentine and phlogopite. The results of field and petrographic observations suggest that the PBKF pectolite is of secondary origin, having formed during the hydrothermal alteration of the Carolina kimberlitic intrusion.
DS202012-2228
2020
Dantas, E.L.Marimon, R.S., Trouw, R.A.J., Dantas, E.L.Significance of age periodicity in the continental crust record: the Sao Francisco craton and adjacent Neoporterozoic orogens as a case study.Gondwana Research, Vol. 86, pp. 144-163. pdfSouth America, Brazilmagmatism

Abstract: The São Francisco Craton, in Brazil, together with adjacent orogenic systems formed during Gondwana assemblage, are well-suited for the study of crustal growth processes. The region's geological history is marked by a series of complete tectono-metamorphic cycles, from the Archean to late Neoproterozoic, comprising arc-related magmatism followed by continental collisions and ultimately post-tectonic igneous events and rifting. In this contribution, a comprehensive isotopic database was compiled from the literature, composed mainly of high-quality U-Pb magmatic and metamorphic ages (ca. 1000), together with Lu-Hf (ca. 1300) and Sm-Nd (ca. 300) data. Using this database, combined with a tectonic/geochemical synthesized review of the region, it is possible to test which of the available contending models can better explain the apparent periodicity in the formation of the continental crustal. Some interpreted the peaks and troughs in the crustal age record as periods of increased magmatic production, controlled by periodic mantellic events. Another hypothesis is that subduction-related rocks are shielded from tectonic erosion after continental amalgamation, the peaks thus reflecting enhanced preservation potential. The latter hypothesis is favored, as the variability regarding the timing of arc-related peak magmatic production (U-Pb age peaks) from different tectonic provinces around the globe and in the considered regions, coupled to the fact that peak arc-production is always closely followed in time by major continental amalgamations (supercontinent formation), precludes a unified global causation effect, such as mantellic overturns or slab avalanches, and supports the preservation bias hypothesis. Furthermore, the worldwide (including the São Francisco Craton) occurrence of plume-related magmatism is concentrated during the periods of supercontinent break-up (i.e. after major collisions), which better relates to a top-down control on mantle convection and opposes most of the models that advocate for the primary periodicity of magmatic production, which predict enhanced plume activity slightly prior or concomitant to supercontinent formation events.
DS201911-2516
2019
Dantas de Araujo, A.J.Dantas de Araujo, A.J., Bongiolo, E.M., Avila, C.A.The southern Sao Francisco craton puzzle: insights from aerogeophysical and geological data.Journal of South American Earth Sciences, Vol. 94, 102203 14p. PdfSouth America, Brazilgeophysics - magnetics

Abstract: Accretionary orogens are considered as the result of the major crust production process, and terranes are accreted material representing distinctive assemblages regarding age and evolution. Scientific advances in the last years show that the southernmost São Francisco Craton includes Archean, Paleoproterozoic and Neoproterozoic areas. We used aerogeophysical data and field geology to understand the extension of individual pieces of this tectonic puzzle. We described five magnetometric lineaments. A-, B- and C-lineaments are related to dyke swarms of different ages. D- and E-lineaments represent regional-scale tectonic structures. In a tectonic perspective, we have identified the following terranes: (i) the Archean São Tiago crust (2.67?Ga), which is part of the São Francisco proto-craton; two Siderian juvenile arcs, represented by the (ii) Cassiterita (2.47?Ga) and the (iii) Resende Costa/Lagoa Dourada (2.36-2.35?Ga) orthogneisses; and two Rhyacian arcs, the (iv) juvenile Serrinha (2.22-2.20?Ga) and the continental Ritápolis (2.19-2.10?Ga) arcs. Tectonic terranes and five magnetic subdomains were identified on the basis of (i) association of shear zones/faults with quartz veins in the field; (ii) low- and high-intensity magnetic anomalies; (iii) sharp contrast in Euler solution intensities; and (iv) high-contrast in radioelement contents in the gammaspectrometric maps. Processing of aerogeophysical data permitted us to propose a new scenario on the evolution of the southern São Francisco Craton, and in particular of the Mineiro belt. The integration between aerogeophysical, new and compiled geologic information, provides a robust model for the understanding of individual tectonic pieces of the studied area.
DS200712-0114
2007
D'AntonioBrotzu, P., Melluso, L., Bennio, L., Gomes, Lustrino, Morbidelli, Morra, Ruberti, Tassarini, D'AntonioPetrogenesis of the Early Cenozoic potassic alkaline complex of Morro de Sao Joao, southeastern Brazil.Journal of South American Earth Sciences, Vol. 24, 1, June pp. 93-115.South America, BrazilAlkalic
DS2002-0315
2002
D'Antonio, M.Conticelli, S., D'Antonio, M., Pinarelli, L., VicettaSource contamination and mantle heterogeneity - genesis of Italian potassic andMineralogy and Petrology, Vol. 74, 2-4, pp. 189-222.Italy, TuscanyGeochronology, Alkaline rocks
DS2002-1046
2002
D'Antonio, M.Melluso, L., Sethna, S.F., D'Antonio, M., Javeri, BennioGeochemistry and petrogenesis of sodic and potassic mafic alkaline rocks in the Deccan volcanic Province.Mineralogy and Petrology, Vol. 74, 2-4, pp. 323-42.IndiaAlkaline rocks, Deposit - Mumbai area
DS2003-0934
2003
D'Antonio, M.Melluso, L., Morra, V., Brotszu, P., D'Antonio, M., Bennio, L.Petrogenesis of the Late Cretaceous tholeiitic magmatism in the passive margins ofGeological Society of America Special Paper, No. 362, chapter 6.MadagascarMagmatism
DS1996-0712
1996
Danyushevskey, L.V.Kamperman, M., Danyushevskey, L.V., Taylor, W., JablonskiDirect oxygen measurements of chromium rich spinel: implications for spinelstoichiometry.American Mineralogist, Vol. 81, Sept-Oct., pp. 1186-1194.AustraliaDiamond indicator spinel, Deposit -Aries, Argyle
DS1993-0770
1993
DanyushevskiyKamenetskiy, V.S., Portnyagin, M.V., Sobolev, A.V., DanyushevskiyMagma composition and crystallization conditions of the picrite-basalt suite in the Tumrok Ridge, East KamchatkaGeochemistry International, Vol.30, No. 3, March pp. 58-73RussiaPicrites
DS1991-0823
1991
Danyushevskiy, L.V.Kamenetsky, V.S., Danyushevskiy, L.V., Zinkevich, V.P., TsukanovNew dat a on the picrites in the Cape Sharom Hills, KamchatkaGeochemistry International, Vol. 28, No. 11, pp. 133-140RussiaPicrites, Geochemistry
DS1992-0333
1992
Danyushevskiy, L.V.Danyushevskiy, L.V., Sobolev, A.V., Kononkova, N.N.Methods of studying melt inclusions in minerals during investigations on water bearing primitive mantle melts (Tonga Trench boninites)Geochemistry International, Vol. 29, No. 7, pp. 48-61GlobalBoninites
DS200512-0088
2005
DanyushevskyBindeman, I.N., Eiler, J.M., Yogodzinski, Y., Stern, C.R., Grove, T.L., Portnyagin, Hoernle, DanyushevskyOxygen isotope evidence for slab melting in modern and ancient subduction zones.Earth and Planetary Science Letters, Vol. 235, 3-4, July 15, pp. 480-496.MantleSubduction
DS2000-0204
2000
Danyushevsky, L.Danyushevsky, L.Sulphide inclusions in olivine phenocrysts from primitive magmasCentre for Ore Deposits, Codes, Ore Solutions, No. 8, p. 5.GlobalMagmatism - sulfides
DS201508-0382
2015
Danyushevsky, L.Xie, Y., Li, Y., Hou, Z., Cooke, D.R., Danyushevsky, L., Dominy, S.C., Yin, S.A model for carbonatite hosted REE mineralization - the Mianning-Dechang REE belt, western Sichuan Province, China.Ore Geology Reviews, Vol. 70, pp. 595-612.ChinaCarbonatite
DS201704-0632
2017
Danyushevsky, L.Kendrick, M.A., Hemond, C., Kamenetsky, V.S., Danyushevsky, L., Devey, C.W.Seawater cycled throughout Earth's mantle in partially serpentinized lithosphere.Nature Geoscience, Vol. 10, 3, pp. 222-228.MantleGeochemistry - water

Abstract: The extent to which water and halogens in Earth’s mantle have primordial origins, or are dominated by seawater-derived components introduced by subduction is debated. About 90% of non-radiogenic xenon in the Earth’s mantle has a subducted atmospheric origin, but the degree to which atmospheric gases and other seawater components are coupled during subduction is unclear. Here we present the concentrations of water and halogens in samples of magmatic glasses collected from mid-ocean ridges and ocean islands globally. We show that water and halogen enrichment is unexpectedly associated with trace element signatures characteristic of dehydrated oceanic crust, and that the most incompatible halogens have relatively uniform abundance ratios that are different from primitive mantle values. Taken together, these results imply that Earth’s mantle is highly processed and that most of its water and halogens were introduced by the subduction of serpentinized lithospheric mantle associated with dehydrated oceanic crust.
DS1994-1652
1994
Danyushevsky, L.V.Sobolev, A.F., Danyushevsky, L.V.Petrology and geochemistry of boninites from the north terminations of the Tonga Trench - high Ca magmas.Journal of Petrology, Vol. 35, pt. 5, pp. 1183-1211.GlobalBoninites
DS2001-0312
2001
Danyushevsky, L.V.Fallon, T.J., Danyushevsky, L.V., Green, D.M.Peridotite melting at 1 GPA: reversal experiments on partial melt compositions produced by peridotite basaltJournal Petrology, Vol. 42, No. 12, pp. 2363-85.MantleExperiments - sandwich, Melting
DS2002-0349
2002
Danyushevsky, L.V.Danyushevsky, L.V., McNeill, A.W., Sobolev, A.V.Experimental and petrological studies of melt inclusions in phenocrysts from mantle derived magmas:Chemical Geology, Vol.183, 1-4, pp.5-24.MantleOverview - techniques, advantages and complications, Magmas
DS2002-0350
2002
Danyushevsky, L.V.Danyushevsky, L.V., Sokolov, S., Falloon, T.J.Melt inclusions in olivine phenocrysts: using diffusive re-equilibration to determine theJournal of Petrology, Vol. 43, 9, Sept.pp. 1651-72.GlobalOlivine rocks
DS200512-0207
2004
Danyushevsky, L.V.Danyushevsky, L.V., Leslie, R.A.J., Crawford, A.J., Durance, P.Melt inclusions in primitive olivine phenocrysts: the role of localized reaction processes in the origin of anomalous compositions.Journal of Petrology, Vol. 45, 12, pp. 2531-2553.Petrology - not specific to diamonds
DS200512-0495
2004
Danyushevsky, L.V.Kamenetsky, M.B., Sobolev, A.V., Kamenetsky, V.S., Maas, R., Danyushevsky, L.V., Thomas, R., Pokhilenko, N.P., Sobolev, N.V.Kimberlite melts rich in alkali chlorides and carbonates: a potent metasomatic agent in the mantle.Geology, Vol. 32, 10, Oct. pp. 845-848.Russia, Siberia, YakutiaUdachnaya, Group I, volatiles, metasomatism, inclusions
DS200712-0303
2007
Danyushevsky, L.V.Fallon, T.J., Danyushevsky, L.V., Ariskin, A., Green, D.H., Ford, C.E.The application of olivine geothermometry to infer crystallization temperatures of parental liquids; implications for the temperature of MORB magmas.Chemical Geology, Vol. 241, 3-4, pp. 207-233.MantleGeothermometry
DS200812-0106
2008
Danyushevsky, L.V.Berry, A.J., Danyushevsky, L.V., O'Neill, H.S.C., Newville, M., Sutton, S.R.Oxidation state of iron in komatiitic melt inclusions indicates hot Archean mantle.Nature, Vol. 455, 7215, Oct. 16, pp. 960-963.MantleKomatiite
DS201611-2144
2016
Danyushevsky, L.V.Stepanov, A.S., Hermann, J., Rubatto, D., Korsakov, A.V., Danyushevsky, L.V.Melting history of an ultrahigh pressure paragneiss revealed by multiphase solid inclusions in garnet, Kokchetav Massif, Kazakhstan.Journal of Petrology, in press available, 24p.Russia, KazakhstanGarnet inclusions

Abstract: Abundant multiphase solid inclusions (MSI) were found in garnet in an ultrahigh-pressure (UHP) paragneiss from the Kokchetav complex, Kazakhstan. The MSI are composed of mineral associations that include rock-forming and accessory minerals, which crystallized during exhumation. We present experimental and analytical protocols for how such inclusions can be homogenized to glass and analysed for major and trace elements. After homogenization we identified two types of glass. One type is present in garnet porphyroblasts in the melanocratic part of the sample and represents a high-pressure melt formed close to peak conditions of >45 kbar, 1000°C. These inclusions are characterized by high concentrations of light rare earth elements (LREE), Th and U. Extraction of these melts resulted in a pronounced depletion of the Kokchetav gneisses in those elements. Measured partition coefficients of large ion lithophile elements (LILE) between phengite inclusions and melt inclusions are DRb?=?1•9-2•5, DBa?=?1•1-6•9 and DCs?=?0•6-0•8, resulting in limited depletion of these elements during partial melting in the presence of phengite. The Nb concentration in melts (27?ppm) is about double that in the restite (15?ppm), indicating slightly incompatible behaviour during UHP anatexis, despite the presence of residual accessory rutile and phengite. A second type of inclusion occurs in garnet from the leucocratic part of the rock and represents a late-stage melt formed during exhumation at 650-750°C and crustal pressures. These inclusions are characterized by low LREE and Nb and high U. Zircon domains formed during high-temperature melting are characterized by high Ti content (100-300?ppm) and unfractionated Th/U (0•4-0•8), whereas the low-temperature domains display low Ti (10?ppm) and Th/U (0•08). The composition of UHP melts with moderate enrichment in LILE, no depletion in Nb and extreme enrichment in LREE and Th is remarkably different from the trace element signature of arc basalts, arguing against involvement of this type of melting in the generation of arc crust. The composition of the UHP melt inclusions is similar to that of melt inclusions from HP crustal xenoliths from Pamir and also to some shoshonites from Tibet. UHP anatexis, as observed in the Kokchetav massif, might be related to the formation of shoshonitic alkaline igneous rocks, which are common in collisional settings.
DS201907-1527
2019
Danyushevsky, L.V.Batanova, V.G., Thompson, J.M., Danyushevsky, L.V., Portnyagin, M.V., Garbe-Schonberg, D., Hauri, E., Kimura, J-I., Chang, Q., Senda, R., Goemann, K., Chauvel, C., Campillo, S., Ionov, D.A., Sobolev,A.V.New olivine reference material for in situ microanalysis.Geostandards and Geoanalytical Research, in press available, 21p.Asia, Mongoliaolivine

Abstract: A new olivine reference material - MongOL Sh11-2 - for in situ analysis has been prepared from the central portion of a large (20 × 20 × 10 cm) mantle peridotite xenolith from a ~ 0.5 My old basaltic breccia at Shavaryn-Tsaram, Tariat region, central Mongolia. The xenolith is a fertile mantle lherzolite with minimal signs of alteration. Approximately 10 g of 0.5-2 mm gem quality olivine fragments were separated under binocular microscope and analysed by EPMA, LA-ICP-MS, SIMS and bulk analytical methods (ID-ICP-MS for Mg and Fe, XRF, ICP-MS) for major, minor and trace elements at six institutions world-wide. The results show that the olivine fragments are sufficiently homogeneous with respect to major (Mg, Fe, Si), minor and trace elements. Significant inhomogeneity was revealed only for phosphorus (homogeneity index of 12.4), whereas Li, Na, Al, Sc, Ti and Cr show minor inhomogeneity (homogeneity index of 1-2). The presence of some mineral and fluid-melt micro-inclusions may be responsible for the inconsistency in mass fractions obtained by in situ and bulk analytical methods for Al, Cu, Sr, Zr, Ga, Dy and Ho. Here we report reference and information values for twenty-seven major, minor and trace elements.
DS200612-0305
2006
Daogong, C.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
DS1996-0328
1996
Dao-Huy, N-T.Dao-Huy, N-T.Financing alternatives for junior mining companies.... IBK capital usualpresentationMining Asia Conference Held May Singapore, GlobalEconomics -investments
DS1996-0295
1996
Daoud, D.Cookenboo, H., Orchard, M., Daoud, D.Middle Devonian conodonts from limestone xenoliths in the Jerichokimberlite, northwest Territories.Northwest Territories Exploration Overview, Nov. 26, p. 3-10 -3-11.Northwest TerritoriesKimberlite, paleontology, Deposit - Jericho
DS1998-0273
1998
Daoud, D.K.Cookenboo, H.O., Orachard, M.J., Daoud, D.K.Remnants of Paleozoic cover on the Archean Canadian Shield: limestone xenoliths from kimberlites in SlaveGeology, Vol. 26, No. 5, May pp. 391-394.Northwest TerritoriesSlave Craton - central, Deposit - Jericho
DS1991-0340
1991
Daoud, M.Daoud, M., MicheletContribution to the automatic extraction of linear structures from satellite imagery: thesisSaskatchewan Research Council, 55p. approx. $30.00 United StatesSaskatchewanStructures, Remote sensing
DS201412-0707
2004
Daouda-YaoPouclet, A., Allialy, M., Daouda-Yao, Esso, B.Decouverte d'un diatreme de kimberlite diamantifere a Seguela en Cote-d'Ivoire.Comptes Rendus Geoscience, Vol. 336, pp. 9-17.Africa, Ivory CoastDiatreme
DS200412-1571
2004
Daouda-Yao, B.Poucler, A., Allialy, M., Daouda-Yao, B., Esso, B.Discovery of a diamond bearing kimberlite diatreme at Seguela in Ivory Coast.Comptes Rendus Geoscience, Vol. 336, 1, Jan. pp. 9-17.Africa, Ivory CoastLamproite, dikes
DS1998-0272
1998
Daould, D.K.Cookenboo, H.O., Kopylova, M.G., Daould, D.K.A chemically and texturally distinct layer of Diamondiferous eclogite beneath central Slave Craton7th International Kimberlite Conference Abstract, pp. 164-6.Northwest TerritoriesGeochemistry - eclogite, Deposit - Jericho
DS201809-2013
2018
Dapper, F.A.Dapper, F.A., Cottrell, E.Experimental investigation and peridotite oxybarometers: implications for spinel thermodynamic models and Fe3+ compatibility during generation of upper mantle melts.American Mineralogist, Vol. 103, pp. 1056-1067.Mantlemelting
DS200712-0755
2007
Daradich, A.Moucha, R., Forte, A.M., Mitrovica, J.X., Daradich, A.Lateral variations in mantle rheology: implications for convection related surface observables and inferred viscosity models.Geophysical Journal International, Vol. 169, 1, pp. 113-135.MantleGeophysics - seismics
DS200712-0756
2007
Daradich, A.Moucha, R., Forte, A.M., Mitrovica, J.X., Daradich, A.Lateral variations in mantle rheology: implications for convection related surface observables and inferred viscosity models.Geophysical Journal International, Vol. 169, 1, pp. 113-135.MantleGeophysics - seismics
DS2002-0351
2002
Darby, B.J.Darby, B.J., Ritts, B.D.Mesozoic contractional deformation in the middle of the Asian tectonic collage: the intraplate Western Ordos fold thrust belt, China.Earth and Planetary Science Letters, Vol. 205, 1-2, pp. 13-24.ChinaTectonics
DS200612-0306
2006
Darby, B.J.Darby, B.J., Gehrels, G.Detrital zircons for the North Chin a Block.Journal of Asian Earth Sciences, Vol. 26, 6, May pp. 637-648.ChinaGeochronology - not specific to diamonds
DS1984-0209
1984
Darby, D.A.Darby, D.A.Trace Elements in Ilmenite: a Way to Discriminate Provenance or Age in Coastal Sands.Geological Society of America (GSA) Bulletin., Vol. 95, PP. 1208-1218.United States, Appalachia, Virginia, North CarolinaSampling, Petrography
DS2002-0205
2002
Darbyshire, D.Brewer, T.S., Ahall, K.I., Darbyshire, D., Menuge, J.Geochemistry of late Mesoproterozoic volcanism in southwestern Scandinavia: implications for ...plate..Journal of Geological Society of London, Vol. 159, 2, pp. 129-44.ScandinaviaSveconorwegian Grenvillian plate tectonic models, Tectonics
DS1989-0891
1989
Darbyshire, D.P.F.Litherland, M., Annells, R.N., Darbyshire, D.P.F., Fletcher, C.J.N.The Proterozoic of Eastern Bolivia and its relationship to the Andean mobile beltPrecambrian Research, Vol. 43, pp. 157-174Andes, BoliviaProterozoic, Tectonics
DS1996-0329
1996
Darbyshire, D.P.F.Darbyshire, D.P.F., Pitfield, P.E.J., Campbell, S.D.G.Late Archean and Early Proterozoic gold tungsten mineralization in the Zimbabwe Archean craton: isotopesGeology, Vol. 24, No. 1, Jan. pp. 19-22ZimbabweCraton, Geochronology
DS2000-0205
2000
Darbyshire, D.P.F.Darbyshire, D.P.F.The Precambrian of Eastern Bolivia - a Sm neodymium isotope studyIgc 30th. Brasil, Aug. abstract only 1p.BoliviaGeochronology, Tectonics
DS200912-0149
2009
Darbyshire, F.Darbyshire, F.Upper mantle structure and azimuthal anisotropy beneath Hudson Bay from rayleigh wave tomography.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, Ontario, ManitobaGeophysics - seismics
DS200912-0150
2009
Darbyshire, F.Darbyshire, F., Lebedev, S.Rayleigh wave velocity heterogeneity and multilayered azimuthal anisotropy of the Superior Craton, Ontario.Geophysical Journal International, Vol.176, 1, pp. 215-234.Canada, OntarioGeophysics
DS200912-0197
2009
Darbyshire, F.Eaton, D.W., Darbyshire, F., Evans, R.L., Grutter, H., Jones, A.G., Yuan, X.The elusive lithosphere asthenosphere boundary ( LAB) beneath cratons.Lithos, Vol. 109, 1-2, pp. 1-22.MantleBoundary
DS201012-0177
2010
Darbyshire, F.Eaton, D.W., Darbyshire, F.Lithospheric architecture and tectonic evolution of the Hudson Bay region.Tectonophysics, Vol. 480, 1-4, pp. 1-22.Canada, OntarioOrogen
DS201212-0543
2012
Darbyshire, F.Pawlak, A., Eaton, D.w.,Darbyshire, F., Lebedev, S., Bastow, I.D.Crustal anisotropy beneath Hudson Bay from ambient noise tomography: evidence for post-orogenic lower crustal flow?Journal of Geophysical Research, in preparationCanada, Ontario, QuebecGeophysics - seismics
DS201212-0544
2012
Darbyshire, F.Pawlak, A., Eaton, D.W., Darbyshire, F., Lebedev, S., Bastow, I.D.Crustal anisotropy beneath Hudson Bay from ambient noise tomography: evidence for post-orogenic lower crustal flow?Journal of Geophysical Research, Vol. 117, B8 B08301Canada, Ontario, QuebecTomography
DS201312-0278
2013
Darbyshire, F.Frederiksen, A.W., Bollmann, T., Darbyshire, F., Van der Lee, S.Modification of continental lithosphere by tectonic processes: a tomographic image of central North America.Journal of Geophysical Research, 50060Canada, United StatesTomography - Laurentia, Superior
DS201706-1090
2017
Darbyshire, F.Levin, V., Servali, A., VanTongeren, J., Menke, W., Darbyshire, F.Crust-mantle boundary in eastern North America, from the (oldest) craton to the (youngest) rift.Geological Society of America, SPE 526 pp. 107-132.United Statescraton

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

Abstract: The North American continent consists of a set of Archean cratons, Proterozoic orogenic belts, and a Sequence of Phanerozoic accreted terranes. We present an ~1250-km-long seismological profile that crosses the Superior craton, Grenville Province, and Appalachian domains, with the goal of documenting the thickness, internal properties, and the nature of the lower boundary of the North American crust using uniform procedures for data selection, preparation, and analysis to ensure compatibility of the constraints we derive. Crustal properties show systematic differences between the three major tectonic domains. The Archean Superior Province is characterized by thin crust, sharp Moho, and low values of Vp/Vs ratio. The Proterozoic Grenville Province has some crustal thickness variation, near-uniform values of Vp/Vs, and consistently small values of Moho thickness. Of the three tectonic domains in the region, the Grenville Province has the thickest crust. Vp/Vs ratios are systematically higher than in the Superior Province. Within the Paleozoic Appalachian orogen, all parameters (crustal thickness, Moho thickness, Vp/Vs ratio) vary broadly over distances of 100 km or less, both across the strike and along it. Internal tectonic boundaries of the Appalachians do not appear to have clear signatures in crustal properties. Of the three major tectonic boundaries crossed by our transect, two have clear manifestations in the crustal structure. The Grenville front is associated with a change in crustal thickness and crustal composition (as reflected in Vp/Vs ratios). The Norumbega fault zone is at the apex of the regional thinning of the Appalachian crust. The Appalachian front is not associated with a major change in crustal properties; rather, it coincides with a zone of complex structure resulting from prior tectonic episodes, and thus presents a clear example of tectonic inheritance over successive Wilson cycles.
DS201711-2524
2017
Darbyshire, F.Liddell, M.V., Bastow, I., Darbyshire, F., Gilligan, A., Pugh, S.The formation of Laurentia: evidence from shear wave splitting.Earth and Planetary Science Letters, Vol. 479, pp. 170-178.Canada, Nunavut, Baffin Islandgeophysics - seismics

Abstract: The northern Hudson Bay region in Canada comprises several Archean cratonic nuclei, assembled by a number of Paleoproterozoic orogenies including the Trans-Hudson Orogen (THO) and the Rinkian-Nagssugtoqidian Orogen. Recent debate has focused on the extent to which these orogens have modern analogues such as the Himalayan-Karakoram-Tibet Orogen. Further, the structure of the lithospheric mantle beneath the Hudson Strait and southern Baffin Island is potentially indicative of Paleoproterozoic underthrusting of the Superior plate beneath the Churchill collage. Also in question is whether the Laurentian cratonic root is stratified, with a fast, depleted, Archean core underlain by a slower, younger, thermally-accreted layer. Plate-scale process that create structures such as these are expected to manifest as measurable fossil seismic anisotropic fabrics. We investigate these problems via shear wave splitting, and present the most comprehensive study to date of mantle seismic anisotropy in northern Laurentia. Strong evidence is presented for multiple layers of anisotropy beneath Archean zones, consistent with the episodic development model of stratified cratonic keels. We also show that southern Baffin Island is underlain by dipping anisotropic fabric, where underthrusting of the Superior plate beneath the Churchill has previously been interpreted. This provides direct evidence of subduction-related deformation at 1.8 Ga, implying that the THO developed with modern plate-tectonic style interactions.
DS201809-2058
2018
Darbyshire, F.Liddell, M.V., Bastow, I., Rawlinson, N., Darbyshire, F., Gilligan, A., Watson, E.Precambrian plate tectonics in northern Hudson Bay: evidence from P and S Wave Seismic tomography and analysis of source side effects in relative arrival-time dat a sets.Journal of Geophysical Research, Vol. 123, 7, pp. 5690-5709.Canada, NunavutGeophysics - seismic

Abstract: The geology of northern Hudson Bay, Canada, documents more than 2 billion years of history including the assembly of Precambrian and Archean terranes during several Paleoproterozoic orogenies, culminating in the Trans-Hudson Orogen (THO) ~1.8 Ga. The THO has been hypothesized to be similar in scale and nature to the ongoing Himalaya-Karakoram-Tibetan orogen, but the nature of lithospheric terrane boundaries, including potential plate-scale underthrusting, is poorly understood. To address this problem, we present new P and S wave tomographic models of the mantle seismic structure using data from recent seismograph networks stretching from northern Ontario to Nunavut (60-100°W and 50-80°N). The large size of our network requires careful mitigation of the influence of source side structure that contaminates our relative arrival time residuals. Our tomographic models reveal a complicated internal structure in the Archean Churchill plate. However, no seismic wave speed distinction is observed across the Snowbird Tectonic Zone, which bisects the Churchill. The mantle lithosphere in the central region of Hudson Bay is distinct from the THO, indicating potential boundaries of microcontinents and lithospheric blocks between the principal colliders. Slow wave speeds underlie southern Baffin Island, the leading edge of the generally high wave speed Churchill plate. This is interpreted to be Paleoproterozoic material underthrust beneath Baffin Island in a modern-style subduction zone setting.
DS201810-2391
2018
Darbyshire, F.Zaporozan, T., Fredericksen, A.W., Bryksin, A., Darbyshire, F.Surface wave images of western Canada: lithographic variations across the Cordillera craton boundary.Canadian Journal of Earth Sciences, Vol. 55, pp. 887-896.Canada, Northwest Territories, Alberta, Saskatchewangeophysics - seismic

Abstract: Two-station surface-wave analysis was used to measure Rayleigh-wave phase velocities between 105 station pairs in western Canada, straddling the boundary between the tectonically active Cordillera and the adjacent stable craton. Major variations in phase velocity are seen across the boundary at periods from 15 to 200 s, periods primarily sensitive to upper mantle structure. Tomographic inversion of these phase velocities was used to generate phase velocity maps at these periods, indicating a sharp contrast between low-velocity Cordilleran upper mantle and high-velocity cratonic lithosphere. Depth inversion along selected transects indicates that the Cordillera-craton upper mantle contact varies in dip along the deformation front, with cratonic lithosphere of the Taltson province overthrusting Cordilleran asthenosphere in the northern Cordillera, and Cordilleran asthenosphere overthrusting Wopmay lithosphere further south. Localized high-velocity features at sub-lithospheric depths beneath the Cordillera are interpreted as Farallon slab fragments, with the gap between these features indicating a slab window. A high-velocity feature in the lower lithosphere of the Slave province may be related to Proterozic or Archean subduction.
DS202006-0920
2020
Darbyshire, F.Foster, A., Darbyshire, F., Schaeffer, A.Anisotropic structure of the central North American craton surrounding the Mid-continent rift: evidence form Rayleigh waves.Precambrian Research, Vol. 342, 18p. PdfUnited States, Canadageophysics - seismics
DS2000-0206
2000
Darbyshire, F.A.Darbyshire, F.A., White, R.S., Priestly, K.F.Structure of the crust and uppermost mantle of Iceland from a combined seismic and gravity study.Earth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.409-28.GlobalMantle - structure, Geophysics - seismics
DS200412-0406
2004
Darbyshire, F.A.Darbyshire, F.A., Larsen, T.B., Mosegaard, K., Dahl Jensen, T., Gudmundsson, O., Bach, T., Gregersen, S., PedeA first detailed look at the Greenland lithosphere and upper mantle; using Rayleigh wave tomography.Geophysical Journal International, Vol. 158, 1, pp. 267-286.Europe, GreenlandGeophysics - seismic
DS200512-0208
2005
Darbyshire, F.A.Darbyshire, F.A.Upper mantle structure of Arctic Canada from Rayleigh wave dispersion.Tectonophysics, Advanced in press,Canada, ArcticGeophysics - seismics, modeling
DS200712-0327
2007
Darbyshire, F.A.Frederickson, A.W., Miong, S.K., Darbyshire, F.A., Eaton, D.W., Rondenay, S., Sol, S.Lithospheric variations across the Superior Province, Ontario Canada: evidence from tomographic wave splitting.Journal of Geophysical Research, Vol. 112, B7, B07318.Canada, OntarioGeophysics - seismics
DS201012-0136
2010
Darbyshire, F.A.Darbyshire, F.A., Eaton, D.W.The lithospheric root beneath Hudson Bay, Canada from Rayleigh wave dispersion: no clear seismological distinction between Archean and Proterozoic mantle.Lithos, Vol. 120, 1-2, Nov. pp. 144-159.Canada, Ontario, Manitoba, QuebecGeophysics - seismics
DS201112-0066
2011
Darbyshire, F.A.Bastow, I.D., Thompson, D.A., Wookey, J., Kendall, J-M., Helffrich, G., Snyder, D.B., Eaton, D.W., Darbyshire, F.A.Precambrian plate tectonics: seismic evidence from northern Hudson Bay, Canada.Geology, Vol. 39, 1, pp. 91-94.Canada, Ontario, Quebec, Manitoba, Northwest TerritoriesGeophysics - seismics
DS201212-0757
2012
Darbyshire, F.A.Villamaire, M., Darbyshire, F.A., Bastow, I.D.3D mantle structure of the eastern Canadian shield and northeastern Appalachians from P-wave travel time tomography.Earth and Planetary Science Letters, in preparationCanadaTomography
DS201212-0758
2012
Darbyshire, F.A.Villemaire, M., Darbyshire, F.A., Bastow, I.D.P wave tomography of eastern North America: evidence for mantle evolution from Archean to Phanerozoic, and modification during subsequent hotspot tectonism.Journal of Geophysical Research, Vol. 117, B12302, 15p.Mantle, North America, CanadaTomography, plumes
DS201503-0136
2015
Darbyshire, F.A.Bastow, I.D., Eaton, D.W., Kendall, J-M., Helffrich, G., Snyder, D.B., Thompson, D.A., Wookey, J., Darbyshire, F.A., Pawlak, A.E.The Hudson Bay lithospheric experiment ( HuBLE): insights into Precambrian plate tectonics and the development of mantle keels.Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 41-67.Canada, Ontario, QuebecGeotectonics

Abstract: Hudson Bay Lithospheric Experiment (HuBLE) was designed to understand the processes that formed Laurentia and the Hudson Bay basin within it. Receiver function analysis shows that Archaean terranes display structurally simple, uniform thickness, felsic crust. Beneath the Palaeoproterozoic Trans-Hudson Orogen (THO), thicker, more complex crust is interpreted as evidence for a secular evolution in crustal formation from non-plate-tectonic in the Palaeoarchaean to fully developed plate tectonics by the Palaeoproterozoic. Corroborating this hypothesis, anisotropy studies reveal 1.8 Ga plate-scale THO-age fabrics. Seismic tomography shows that the Proterozoic mantle has lower wavespeeds than surrounding Archaean blocks; the Laurentian keel thus formed partly in post-Archaean times. A mantle transition zone study indicates ‘normal’ temperatures beneath the Laurentian keel, so any cold mantle down-welling associated with the regional free-air gravity anomaly is probably confined to the upper mantle. Focal mechanisms from earthquakes indicate that present-day crustal stresses are influenced by glacial rebound and pre-existing faults. Ambient-noise tomography reveals a low-velocity anomaly, coincident with a previously inferred zone of crustal stretching, eliminating eclogitization of lower crustal rocks as a basin formation mechanism. Hudson Bay is an ephemeral feature, caused principally by incomplete glacial rebound. Plate stretching is the primary mechanism responsible for the formation of the basin itself.
DS201609-1706
2016
Darbyshire, F.A.Boyce, A., Bastow, I.D., Darbyshire, F.A., Ellwood, A.G., Gilligan, A., Levin, V., Menke, W.Subduction beneath Laurentia modifies the eastern North American cratonic edge: evidence from P wave and S wave tomography.Journal of Geophysical Research,, Vol. 121, 7, pp. 5013-5030.CanadaSubduction

Abstract: The cratonic cores of the continents are remarkably stable and long-lived features. Their ability to resist destructive tectonic processes is associated with their thick (~250 km), cold, chemically depleted, buoyant lithospheric keels that isolate the cratons from the convecting mantle. The formation mechanism and tectonic stability of cratonic keels remains under debate. To address this issue, we use P wave and S wave relative arrival-time tomography to constrain upper mantle structure beneath southeast Canada and the northeast USA, a region spanning three quarters of Earth's geological history. Our models show three distinct, broad zones: Seismic wave speeds increase systematically from the Phanerozoic coastal domains, through the Proterozoic Grenville Province, and to the Archean Superior craton in central Québec. We also recover the NW-SE trending track of the Great Meteor hot spot that crosscuts the major tectonic domains. The decrease in seismic wave speed from Archean to Proterozoic domains across the Grenville Front is consistent with predictions from models of two-stage keel formation, supporting the idea that keel growth may not have been restricted to Archean times. However, while crustal structure studies suggest that Archean Superior material underlies Grenvillian age rocks up to ~300 km SE of the Grenville Front, our tomographic models show a near-vertical boundary in mantle wave speed directly beneath the Grenville Front. We interpret this as evidence for subduction-driven metasomatic enrichment of the Laurentian cratonic margin, prior to keel stabilization. Variable chemical depletion levels across Archean-Proterozoic boundaries worldwide may thus be better explained by metasomatic enrichment than inherently less depleted Proterozoic composition at formation.
DS202004-0529
2020
Darbyshire, F.A.Petrescu, L., Bastow, I.D., Darbyshire, F.A., Gilligan, A., Bodin, T., Menke, W., Levin, V.Three billion years of crustal evolution in eastern Canada: constraints from receiver functions.Journal of Geophysical Research: Solid Earth, in press available, 24p. PdfCanadageophysics - seismics

Abstract: The geological record of SE Canada spans more than 2.5Ga, making it a natural laboratory for the study of crustal formation and evolution over time. We estimate the crustal thickness, Poisson's ratio, a proxy for bulk crustal composition, and shear velocity (Vs) structure from receiver functions at a network of seismograph stations recently deployed across the Archean Superior craton, the Proterozoic Grenville and the Phanerozoic Appalachian provinces. The bulk seismic crustal properties and shear velocity structure reveal a correlation with tectonic provinces of different ages: the post-Archean crust becomes thicker, faster, more heterogenous and more compositionally evolved. This secular variation pattern is consistent with a growing consensus that crustal growth efficiency increased at the end of the Archean. A lack of correlation among elevation, Moho topography, and gravity anomalies within the Proterozoic belt is better explained by buoyant mantle support rather than by compositional variations driven by lower crustal metamorphic reactions. A ubiquitous ~20km thick high-Vs lower-crustal layer is imaged beneath the Proterozoic belt. The strong discontinuity at 20km may represent the signature of extensional collapse of an orogenic plateau, accommodated by lateral crustal flow. Wide anorthosite massifs inferred to fractionate from a mafic mantle source are abundant in Proterozoic geology and are underlain by high Vs lower crust and a gradational Moho. Mafic underplating may have provided a source for these intrusions and could have been an important post-Archean process stimulating mafic crustal growth in a vertical sense.
DS202007-1137
2020
Darbyshire, F.A.Dube, J-M., Darbyshire, F.A., Liddell, M.V., Stephenson, R.Seismic anisotropy of the Canadian High Arctic: evidence from shear wave splitting.Tectonophysics, Vol. 789, 228524, 13p. PdfCanada, Arcticgeophysics - seismics

Abstract: The Canadian High Arctic preserves a long and complex tectonic history, including craton formation, multiple periods of orogenesis, extension and basin formation, and the development of a passive continental margin. We investigate the possible preservation of deformational structures throughout the High Arctic subcontinental lithosphere using measurements of seismic anisotropy from shear wave splitting at 11 seismograph stations across the region, including a N-S transect along Ellesmere Island. The majority of measurements indicate a fast-polarisation orientation that parallels tectonic trends and boundaries, suggesting that lithospheric deformation is the dominant source of seismic anisotropy in the High Arctic; however, a sub-lithospheric contribution cannot be ruled out. Beneath Resolute in the central Canadian Arctic, distinct back-azimuthal variations in splitting parameters can be explained by two anisotropic layers. The upper layer is oriented E-W and correlates with tectonic trends and the inferred lithospheric deformation history of the region. The lower layer has a ~NNE-SSW orientation and may arise from present-day convective mantle flow beneath locally-thinned continental lithosphere. In addition to inferences of anisotropic structure beneath the Canadian High Arctic, measurements from the far north of our study region suggest the presence of an anisotropic zone in the lowermost mantle beneath northwest Alaska.
DS2000-1021
2000
Darch, G.Windley, B.F., Darch, G., Cunningham, W.D.Terrane accretion and crustal growth of central Asia: constraints from Mongolia.Igc 30th. Brasil, Aug. abstract only 1p.GlobalOrogen - Central Asian Orogenic Belt, Craton
DS202004-0534
2020
D'Arco, A.Stagno, V., Stopponi, V., Kono, Y., D'Arco, A., Lupi, S., Romano, C., Poe, B.T., Foustoukos, D.J., Scarlato, P., Manning, C.E.The viscosity and atomic structure of volatile bearing melililititic melts at high pressure and temperature and the transport of deep carbon.Minerals MDPI, Vol. 10, 267 doi: 10.23390/min10030267 14p. PdfMantleMelililite, carbon

Abstract: Understanding the viscosity of mantle-derived magmas is needed to model their migration mechanisms and ascent rate from the source rock to the surface. High pressure-temperature experimental data are now available on the viscosity of synthetic melts, pure carbonatitic to carbonate-silicate compositions, anhydrous basalts, dacites and rhyolites. However, the viscosity of volatile-bearing melilititic melts, among the most plausible carriers of deep carbon, has not been investigated. In this study, we experimentally determined the viscosity of synthetic liquids with ~31 and ~39 wt% SiO2, 1.60 and 1.42 wt% CO2 and 5.7 and 1 wt% H2O, respectively, at pressures from 1 to 4.7 GPa and temperatures between 1265 and 1755 °C, using the falling-sphere technique combined with in situ X-ray radiography. Our results show viscosities between 0.1044 and 2.1221 Pa•s, with a clear dependence on temperature and SiO2 content. The atomic structure of both melt compositions was also determined at high pressure and temperature, using in situ multi-angle energy-dispersive X-ray diffraction supported by ex situ microFTIR and microRaman spectroscopic measurements. Our results yield evidence that the T-T and T-O (T = Si,Al) interatomic distances of ultrabasic melts are higher than those for basaltic melts known from similar recent studies. Based on our experimental data, melilititic melts are expected to migrate at a rate ~from 2 to 57 km•yr-1 in the present-day or the Archaean mantle, respectively.
DS1988-0155
1988
Dardenne, M.A.Dardenne, M.A., Ferreira Filho, C.F., Meirelles, M.R.The role of shoshonitic and calc-alkaline suites in the tectonic Evolution of the Carajas District, BrasilJournal of South American Earth Sciences, Vol. 1, No. 4, pp. 363-372BrazilShoshonite
DS1991-0341
1991
Dardenne, M.A.Dardenne, M.A., Gonzaga, G.M., Campos, J.E.G.The diamond bearing Cretaceous conglomerates of the Canabrava area, MinasGerais, BrasilFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 83-88BrazilConglomerates, Alluvial diamonds
DS1991-0587
1991
Dardenne, M.A.Gonzaga, G.M., Dardenne, M.A.The Jequitai glaciation and the dispersion of diamondsFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 89-94BrazilGeomorphology, Alluvial diamonds
DS1993-1326
1993
Dardenne, M.A.Ronchi, L.H., Touray, J.C., Dardenne, M.A., Beny, C.Arguments for a local contamination of Cretaceous carbonatitic intrusions by Proterozoic CaF2 deposits in southern Brasil.Terra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 45.BrazilCarbonatite, Fluorine
DS1986-0165
1986
Dardis, K.A.Dardis, K.A., Knox, P.R., Weber, D.The Argyle process plant control systemAustralasian Institute of Mining and Metallurgy, Vol. 47, Project symposium 2nd., pp. 77-94AustraliaDeposit, Argyle
DS1994-0375
1994
Dardis, K.A.Dardis, K.A.New diamond prospects: design of pilot plants and test programmes for evaluation and scale up.Signet Preprint The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Diamond Recovery session, May 2, 1994, 23p.AustraliaDiamond recovery, Mineral processing -Argyle example
DS1994-0376
1994
Dardis, K.A.Dardis, K.A., Moncrieff, R.E.HMS diamond plantsSignet Preprint The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Diamond Recovery session, May 2, 1994, 29p.GlobalDiamond recovery, HMS DMS Mineral processing overview
DS1991-0595
1991
Dardykins, L.N.Govorov, I.N., Badredinov, Z.G., Dardykins, L.N., et al.Ultramafic volcanic rocks of the shoshonite-latite seriesDoklady Academy of Sciences USSR Earth Science Scetion, Vol. 310, No. 1-6, September pp. 125-128RussiaShoshonite, Ultramafic
DS201502-0093
2014
Dare, S.Robinson, P.T., Trumbull, R.B., Schmitt, A., Yang, J-S., Li, J-W., Zhou, M-F., Erzinger, J., Dare, S., Xiong, F.The origin and significance of crustal minerals in ophiolitic chromitites and peridotites.Gondwana Research, Vol. 27 2, pp. 486-506.Peridotite
DS200912-0151
2009
Dare, S.A.S.Dare, S.A.S., Pearce, J.A., McDonald, I.,Styles, M.T.Tectonic discrimination of peridotites using fO2 Cr# and Ga Ti Fe111 systematics in chrome spinel.Chemical Geology, Vol. 261, 3-4, April 30, pp. 199-216.TechnologyMineral chemistry database
DS1992-0334
1992
Dargahi-Noubury, G.R.Dargahi-Noubury, G.R.Stochastic modeling based on deterministic formulation: an exampleMathematical Geology, Vol. 24, No. 2, February pp. 161-170GlobalGeostatistics, Modeling
DS1995-0330
1995
D'Argentio, B.Cloetingh, S., D'Argentio, B., Sassi, W.Interplay of extension and compression in basin formation - introductionTectonophysics, Vol. 252, No. 1-4, Dec. 30, pp. 1-6GlobalBasins, Tectonics
DS1994-0042
1994
Dargusch, T.Ambroziak, R.A., Cook, C.A., Goowell, G.R., Dargusch, T.Computer mapping at your desk .. that really works.. short course aboutcreating digital maps on a PC.Geological Society of America (GSA) Short Course, 100p. approx. $ 15.00GlobalBook -table of contents, Computer mapping programs
DS200912-0152
2009
Darling, J.Darling, J., Storey, C., Hawkesworth, G.Impact melt sheet zircons and their implications for the Hadean crust.Geology, Vol. 37, 10, Oct. pp. 927-930.AustraliaZircon mineralogy
DS200712-0148
2007
Darling, T.W.Carpenter, M.A., Darling, T.W., Buckley, A.J., Taylor, P.A.Investigation of eleastic and An elastic phenomena associated with structural pphase transition in perovskites by Resonant Ultrasound Spectroscopy.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.188.MantlePerovskite
DS200712-0149
2007
Darling, T.W.Carpenter, M.A., Darling, T.W., Buckley, A.J., Taylor, P.A.Investigation of eleastic and An elastic phenomena associated with structural pphase transition in perovskites by Resonant Ultrasound Spectroscopy.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.188.MantlePerovskite
DS1997-0240
1997
Darnell, R.Darnell, R.Tax, legal and contractual systems governing mining ventures in RussiaMining in Russia Conference Northern Miner, Oct, Toronto, 18p. slides presentationRussiaMining, Legal, taxation, agreements, decrees
DS1992-0335
1992
Darnley, A.G.Darnley, A.G.Update on the international geochemical mapping projectExplore, No. 76, July pp. 11, 12, 13, 14GlobalGeochemistry, Sample media, spacing
DS1994-0377
1994
Darnley, A.G.Darnley, A.G., et al.A global geochemical database for environmental and resource management.International Geological Correlation Programme (IGCP)Project 259Unesco Publishing Earth Sciences No. 19, 125pGlobalGeochemistry, Book - table of contents
DS1991-1471
1991
Darot, M.Ruffet, C., Gueguen, Y., Darot, M.Rock conductivity and fractal nature of porosityTerra Nova, Vol. 3, No. 3, pp. 265-275GlobalGeophysics, Cole and Cole
DS1995-1624
1995
Darot, M.Ruffet, C., Darot, M., Guguen, Y.Surface conductivity in rocks: a reviewSurveys in Geophysics, Vol. 16, pp. 83-105.GlobalGeophysics - conductivity, Rock interfaces, experimental
DS201512-1907
2015
D'Arpizio, C.D'Arpizio, C., Levato, F., Zito, D., De Montgolfier, J.Luxury goods worldwide market study Fall-Winter 2014.Bain & Company, Nov. 5, 38p. PdfGlobalDiamond market
DS1975-0058
1975
Darracott, B.W.Darracott, B.W.Gravity and Magnetic Surveys of the Diamondiferous Deposits of the Lichtenburg Bakerville Area.Geological Survey of South Africa Annual Report, Vol. 10, P. 132.South AfricaGeophysics, Kimberlites, Prospecting
DS1998-0637
1998
Darrah, K.S.Holm, D.K., Darrah, K.S., Lux, D.R.Evidence for Wide spread ~1760 Ma metamorphism and rapid crustal stabilization of Early Proterozoic Penokean...American Journal of Science, Vol. 298, Jan. pp. 60-81.MinnesotaOrogeny - Penokean, metamorphism
DS1996-0363
1996
Darren, D.Dierker, C., Darren, D.Update on the BHP/ Dia Met northwest Territories diamond projectNorthwest Territories Exploration Overview, Nov. 26, p. 3-13 - 3-14.Northwest TerritoriesExploration update, BHP, Dia Met
DS1992-0336
1992
Darros de Matos, R.M.Darros de Matos, R.M.The northeast Brazilian rift systemTectonics, Vol. 11, No. 4, August pp. 766-791BrazilTectonics, Rift system
DS1983-0187
1983
Dars, R.Cornacchia, M., Dars, R.Un Trait Structural Majeur du Continent Africain. Les Lineaments Centrafricains du Cameroun au Golfe D'aden.Bulletin. SOC. GEOL. (FRANCE), Vol. 25, No. 1, PP. 101-109.GlobalTectonics
DS1989-0328
1989
Dart, R.L.Dart, R.L., Michael, J.A.Contour and subgroup mapping of the Paleozoic subsurface in the Upper Mississippi embaymentGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A206. AbstractMidcontinentMississippi embayment, Reelfoot Rift
DS1991-0342
1991
Dart, R.L.Dart, R.L., Swolfs, H.S.Contemporary stress in northeastern ArkansawEos, Spring Meeting Program And Abstracts, Vol. 72, No. 17, April 23, p. 264ArkansasTectonics, Geophysics -seismics
DS1994-0378
1994
Dart, R.L.Dart, R.L., Swolfs, H.S.Structural style of the Reelfoot RiftGeological Society of America Abstracts, Vol. 26, No. 1, February p. 5. AbstractArkansasTectonics, Reelfoot Rift
DS2002-0023
2002
Dart, R.L.Allaoua Saadi, M.N., Machette,K.M., Haller,K.M., Dart, R.L., Bradley, L-A.Map and database of Quaternary faults and lineaments in BrazilU.s. Geological Survey, OF 02-0230 58p $ 76. http://pubs.usgs.gov/of/2002/ofr-BrazilBlank
DS200412-0019
2002
Dart, R.L.Allaoua Saadi, M.N., Machette,K.M., Haller,K.M., Dart, R.L., Bradley, L-A., De Souza, A.M.P.D.Map and database of Quaternary faults and lineaments in Brazil.U.S. Geological Survey, OF 02-0230 58p $ 76.South America, BrazilMap - structure
DS1860-0655
1890
Darton, N.H.Darton, N.H.On the Occurrence of Basalt Dikes in the Upper Paleozoic Series in the Central Appalachians, Virginia with a Note on The Petrography by J.s. Diller.American Journal of Science, SER. 3, Vol. 39, PP. 269-271.United States, Appalachia, VirginiaPetrography, Related Rocks
DS1860-0887
1895
Darton, N.H.Darton, N.H., Kemp, J.F.A Newly Discovered Dike at de Witt Near Syracuse, New York.petrographic Description by J.f. Kemp.American Journal of Science, 3RD. SER. Vol. 49, PP. 456-462..; ALSO: Geological Society of America (GSA) BULUnited States, New York, AppalachiaRelated Rocks
DS1860-1024
1898
Darton, N.H.Darton, N.H.On Dikes of Felsophyre and Basalt in Central Appalachians Virginia with Notes on the Petrography by A. Keith.American Journal of Science, SER. 4, Vol. 6, PP. 305-315.United States, VirginiaRelated Rocks, Petrography
DS1910-0039
1910
Darton, N.H.Darton, N.H., Blackwelder, E., Siebenthal, C.E.Laramie Sherman Folio, WyomingUnited States Geological Survey (USGS) ATLAS of THE UNITED STATES, 17P.United States, Wyoming, Rocky MountainsRegional Geology
DS1860-0844
1894
Darton, N.P.Hall, J., Darton, N.P.Geology of the Mohawk Valley in Herkimer, Fulton, Montgomery and Saratoga Counties.Thirteenth Annual Report Geological Survey New York, Vol. 1, PP. 409-429.United States, New YorkGeology
DS1860-0894
1895
Darton, N.P.Kemp, J.F., Darton, N.P.A New Intrusive Rock Near SyracuseScience., NEW SER. Vol. 2, PP. 65-66.United States, New YorkGeology
DS2003-0340
2003
Darus, M.Dobrzhinetskaya, L.F., Green, H.W., Weschler, M., Darus, M., Wang, Y.C.Focused ion beam technique and transmission electron microscope studies ofEarth and Planetary Science Letters, Vol. 210, 3-4, pp. 399-410.GermanyTechnology
DS2003-0341
2003
Darus, M.Dobrzhinetskaya, L.F., Green, H.W., Weschler, M., Darus, M., Young-ChungFocused ion beam technique and transmission electron microscope studies ofEarth and Planetary Science Letters, Vol. 210, 3-4, May 30, pp.399-410.GermanyDiamond inclusions
DS200412-0464
2003
Darus, M.Dobrzhinetskaya, L.F., Green, H.W., Weschler, M., Darus, M., Young-Chung, Wang, Massone, H-J., Stockhert, B.Focused ion beam technique and transmission electron microscope studies of microdiamonds from the Saxonian Erzgerbirge, Germany.Earth and Planetary Science Letters, Vol. 210, 3-4, May 30, pp.399-410.Europe, GermanyDiamond inclusions
DS1989-0329
1989
Darwish, M.A.Darwish, M.A., Butt, N.A.Forecasting in the mineral industryInternational Mining, Vol. 6, No. 12, December pp. 12-17GlobalEconomics, Mineral trends and demands
DS201412-0719
2013
DasRai, S.Borah, Kajaljyoti, Das, Gupta, R., Srivastava, S., Shalivahan, P., Sivaram, K., Kumar, K., Meena, S.The South India Precambrian crust and shallow lithospheric mantle: initial results from the India Deep Imaging Experiment ( INDEX).Journal of Earth System Science, Vol. 122, 6, pp. 1435-1453.IndiaDrilling
DS1995-1660
1995
Das, A.K.Sarkar, S.C., Dwivedy, K.K., Das, A.K.Rare earth deposits in India - an outline of their types, distribution, mineralogy geochemistry genesis.Global Tectonics and Metallogeny, Vol. 5, No. 1-2, Oct. pp. 53-61.IndiaCarbonatite, rare earth elements (REE)., Deposits -list
DS200512-0210
2005
Das, B.Das, L.K., Das, B., Chowdbury, S.N., Naskar, D.C., Karunakar, G., Dey, S.K.Configuration of kimberlite bodies, Indravati basinal area, Bastar District, Chhattisgarh.Journal of the Geological Society of India, Vol. 65, 5, pp. 679-688.India, Bastar CratonTectonics
DS1982-0164
1982
Das, G.R.N.Das, G.R.N., Sharma, C.V., Navaneetham, K.V., Chadha, S.K.Carbonatite-alkaline Complex of MundwaraGeological Society INDIA Journal, Vol. 23, No. 12, PP. 604-609.IndiaRelated Rocks
DS201812-2797
2018
Das, H.Das, H., Kobussen, A.F., Webb, K.J., Phillips, D., Maas, R., Soltys, A., Rayner, M.J., Howell, D.Bunder deposit: The Bunder diamond project, India: geology, geochemistry, and age of Saptarshi lamproite pipes.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 201-222.Indiadeposit - Bunder
DS1995-0385
1995
Das, J.D.Das, J.D. , saraf, A.K., Jain, A.K.Fault tectonics of the Shilong plateau and adjoining regions, north-east India using remote sensing dataInternational Journal of Remote Sensing, Vol. 16, No. 9, June pp. 1633-46IndiaRemote Sensing, Tectonics
DS2003-0552
2003
Das, J.D.Harijan, N., Sen, A.K., Sarkar, S., Das, J.D., Kanungo, D.P.Geomorphotectonic around the Sung Valley carbonatite complex, Shillong PlateauGeological Society of India Journal, Vol. 62, 1, pp. 103-109.IndiaCarbonatite
DS2003-0553
2003
Das, J.D.Harijan, N., Sen, A.K., Sarkar, S., Das, J.D., Kanungo, D.P.Geomorphotectonics around the Sung Valley carbonatite Complex Shillong Plateau NEJournal of the Geological Society of India, Vol. 62, 1, July, pp. 103-109.India, northeastCarbonatite
DS200412-0791
2003
Das, J.D.Harijan, N., Sen, A.K., Sarkar, S., Das, J.D., Kanungo, D.P.Geomorphotectonics around the Sung Valley carbonatite Complex Shillong Plateau NE India: a remote sensing and GIS approach.Journal of the Geological Society of India, Vol. 62, 1, July, pp. 103-109.IndiaTectonics Carbonatites
DS201212-0143
2012
Das, J.N.Das, J.N., Korkoppa, M.M., Fareeduddin, Shivana, S., Srivastava, J.K., Gera, N.L.Tuffisitic kimberlite from eastern Dharwar craton, Undraldoddi area, Raichur District, Karnataka, India10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractIndia, KarnatakaDeposit - Undraldoddi area
DS201312-0185
2013
Das, J.N.Das, J.N., Korakoppa, M.M., FareeduddinTuffisitic kimberlite from Eastern Dharwar craton, Undraldoddi area, Raichur District, Karnataka, India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 109-128.India, KarnatakaDeposit - Undraldoddi
DS201412-0164
2014
Das, J.N.Das, J.N.Prospect of gemstones of India in 21st century. Diamond and other gem stonesGeological Society of America Conference Vancouver Oct. 19-22, 1p. AbstractIndiaHistory
DS201412-0165
2013
Das, J.N.Das, J.N., Korakoppa, M.M., Fareeduddin, Shivana, S., Srivastava, J.K., Gera, N.L.Tuffisitic kimberlite from eastern Dharwar craton, Undraldoddi area, Raichur district, Karnataka India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 109-128.India, KarnatakaDeposit - Raichur district
DS201505-0232
2015
Das, J.N.Das, J.N.Prospect of gemstones of India in 21st century.Geological Society of America Annual Meeting, Oct. 24, 1p. AbstractIndiaGemstones
DS201112-0098
2011
Das, K.Bose, S., Dunkley, D.J., Dasgupta, S., Das, K., Arima, M.India-Antarctica-Australia-Laurentia connection in the Paleoproterozoic-Mesoproterozoic revisited: evidence from new zircon U Pb and monzazite chemical age dataGeological Society of America Bulletin, Vol. 123, 9/10 pp. 2031-2049.IndiaEastern Ghats Belt, geochronology
DS1970-0268
1971
Das, K.N.Das, K.N., Lakshmanan, S.Repositories of the Panna Diamond Deposits and Age of the Majhgawan Volcanic Pipe.India Geological Survey Miscellaneous Publishing, No. 19, PP. 95-101.IndiaGeochronology
DS1999-0002
1999
Das, L.K.Agarwal, B.N.P., Das, L.K., Shaw, R.K.Gravity anomalies, tectonics and ore deposits: a predictive genetic mode lover Aravallis, India.Global Tectonics and Met., Vol. 7, No. 1, Feb. pp. 47-52.IndiaGeophysics - gravity, Model - not specific to diamonds
DS1999-0003
1999
Das, L.K.Agarwal, B.N.P., Das, L.K., Shaw, R.K.Tectonics and metallogeny over Central Indian Shield: a geophysicalanalysis.Global Tectonics and Met., Vol. 7, No. 1, Feb. pp. 41-46.IndiaGeophysics - gravity, Tectonics - not specific to diamonds
DS200512-0210
2005
Das, L.K.Das, L.K., Das, B., Chowdbury, S.N., Naskar, D.C., Karunakar, G., Dey, S.K.Configuration of kimberlite bodies, Indravati basinal area, Bastar District, Chhattisgarh.Journal of the Geological Society of India, Vol. 65, 5, pp. 679-688.India, Bastar CratonTectonics
DS200612-0098
2005
Das, L.K.Basu, A., Das, L.K., Moitra, M., Bhattacharya, D., Lahiri, A.K.On the occurrence of rocks of lamproitic affinity in Singhbhum granite, near Rajnaga Tiring area, district of Singhbhum, Jharkland.Journal of the Geological Society of India, Vol. 65, pp. 15-16.IndiaLamproite
DS201510-1764
2015
Das, R.Das, R., Saikia, U., Rai, S.S.The deep geology of South India inferred from Moho depth and Vp/Vs ratio.Geophysical Journal International, Vol. 203, pp. 910-926.IndiaGeophysics - seismics

Abstract: We present a comprehensive study of thickness and composition of the crust; and the nature of crust-mantle boundary beneath Southern India using P-wave receiver function from 119 seismic stations. Data from distributed network of seismograph location encompass geological domains like mid to late Archean Dharwar craton, Archean and Proterozoic metamorphic terrains, Proterozoic basin, rifted margins and escarpments, and Deccan volcanics. Except for the mid to lower crust exhumed Archean terrains (of West Dharwar and Southern Granulite) all other geological domains have crustal thickness in the range 33-40 km. In the western Dharwar, crustal thickness increases from ~40 km in the north to over 50 km in the south. The Archean domain of granulite terrain is thicker (40-45 km) and more mafic compared to its counterpart in south deformed at 550 Ma. Most of the crustal blocks have low to moderate Vp/Vs (1.72-1.76) representing a felsic to intermediate composition. Exception to the above include Archean granulite terrain with high Vp/Vs (1.76–1.81) suggestive of more mafic crust beneath them. When accounted for the paleo burial depth of 15-25 km, the study suggests a possible Himalaya-Tibet like scenario beneath the mid-late Archean in southwestern Dharwar and north granulite terrain whose deeper crust has progressively densified. This led to a gradational crust-mantle transition that is otherwise sharp elsewhere. The study suggests a more homogenized and felsic nature of the Precambrian crust beneath the terrains formed after 2.6 Ga, possibly due to delamination of the mafic lower crust. Our study does not suggest any distinction between late Archean and Proterozoic crust. The Deccan volcanism at 65 Ma does not appear to have altered the crustal character beneath it and is similar to the adjoining late Archean east Dharwar craton. The western Ghat escarpment and the coastal plain formed due to separation of India from Madagascar are underlain by mafic lower crust.
DS1991-0002
1991
Das, R.P.Acharya, S., Anand, S., Reddy, B.R., Das, R.P.Processing of kimberlite tailings to recover magnesium as MgO or MgSO417th. International Mineral Proceedings Congress, Preprints, pp. 199-209.IndiaMineral processing, Kimberlite tailinsg -magnesiuM.
DS1991-1403
1991
Das, R.P.Reddy, B.R., Acharya, S., Anand, S., Das, R.P.Preparation and characterization of magnesium sulfate heptahydrate From kimberlite tailingsJournal of Thermal Analysis, Vol. 37, No. 5, May pp. 945-951GlobalMining, Mineral processing -tailings
DS200812-0263
2008
Das, S.Das, S., Nasipuri, P., Bhattachaya, A., Swaminathan, S.The thrust contact between the Eastern Ghats belt and the adjoining Bastar craton, Eastern India: evidence from mafic granulites and tectonic implications.Precambrian Research, Vol. 162, 1-2, pp. 70-85.IndiaCraton
DS1998-0303
1998
Das, T.Das, T., Nolet, G.Crustal thickness map of the western United States by partitioned waveforminversion.Journal of Geophysical Research, Vol. 103, No. 12, Dec. 10, pp. 30, 021-38.Cordillera, Colorado PlateauTomography, Geophysics - seismic
DS1986-0699
1986
Das, T.P.Sahoo, N., Mishra, K.C., Das, T.P., Schmidt, P.C.Vacancy associated model for anomalous muonium in diamond, silicon andgermaniuM.Hyperfine Interact, Vol. 32, No. 1-4, pp. 619-624GlobalCrystallography, Diamond
DS200412-0407
2004
das Gupta, R.das Gupta, R., Stalker, K., Withers, A.C., Hirschmann, M.M.The transition from carbonate rich to silicate rich melts in eclogite: partial melting experiments of carbonated eclogite at 3 GLithos, ABSTRACTS only, Vol. 73, p. S23. abstractTechnologyEclogite
DS200512-0209
2005
Das Gupta, R.Das Gupta, R., Hirschmann, M.M., Dellas, N.The effect of bulk composition on the solidus of carbonated eclogite from partial melting experiments at 3? GPAContributions to Mineralogy and Petrology, Vol. 149, 3, pp. 288-305.Eclogite, mineral chemistry
DS200612-0307
2006
Das Gupta, R.Das Gupta, R., Hirschmann, M.M.Melting in the Earth's deep upper mantle caused by carbon dioxide.Nature, Vol. 440, 7084, Mar. 30, pp. 659-662.MantleMelting
DS200612-0308
2006
Das Gupta, R.Das Gupta, R., Hirschmann, M.M., Stalker, K.Immiscible transition from carbonate rich to silicate rich melts in the 3 GPa melting interval of eclogite + CO2 and genesis of silica undersaturated Oceanic lavas.Journal of Petrology, Vol. 47, 4, April pp. 647-671.Mantle, Oceanic IslandCarbonatite, eclogites
DS1970-0267
1971
Das gupta, S.P.Das gupta, S.P., Phukan, S.Mineralogy of the Altered Diamondiferous Pipe Rock at Panna, M.p.India Geological Survey Miscellaneous Publishing, No. 19, PP. 114-119.India, Madhya PradeshProspecting, Mineralogy
DS1975-0304
1976
Das Gupta, S.P.Karunakaran, C., Murthy, S.R.N., Das Gupta, S.P.Kimberlites of Wajrakarur and Lattavaram, A.pIndia Geological Survey Miscellaneous Publishing, No. 23, PT. II, PP. 538-548.India, Andhra PradeshGeology
DS1997-0241
1997
Das Neves Calha Ramos, Z.Das Neves Calha Ramos, Z.Eclogitic pyroxenitic xenoliths from the Zero kimberlite, Kuruman areaMsc. Thesis, University Of Witwatersrand, In Prep *ref Only, South AfricaXenoliths, Deposit -Zero
DS201312-0184
2013
Das SharmaDas Sharma, Ramesh, D.S.Imaging mantle lithosphere for diamond prospecting in southeast India.Lithosphere, Vol. 5, no. 4, pp. 331-342.IndiaTectonics
DS201012-0137
2010
Das Sharma, S.Das Sharma, S., Ramesh, D.S., Li, X., Yuan, B., Sreenivas, B., Kind, R.Response of mantle transition zone thickness to plume bouyancy flux.Geophysical Journal International, Vol. 180, 1, pp. 49-58.MantlePlume
DS201806-1245
2018
Dasguota, R.Saga, S., Dasguota, R., Tsuno, K.High pressure phase relations of a depleted peridotite fluxed by CO2, H2O bearing siliceous melts and the origin of mid lithospheric discontinuity.Geochemistry, Geophysics, Geosystems, Vol. 19, 3, pp. 595-620.Mantleperidotites

Abstract: We present phase equilibria experiments on a depleted peridotite (Mg# 92) fluxed with variable proportions of a slab-derived rhyolitic melt (with 9.4 wt.% H2O, 5 wt.% CO2), envisaging an interaction that could occur during formation of continents by imbrication of slabs/accretion of subarc mantles. Experiments were performed with 5 wt.% (Bulk 2) and 10 wt.% (Bulk 1) melt at 950-1175°C and 2-4 GPa using a piston-cylinder and a multi-anvil apparatus, to test the hypothesis that volatile-bearing mineral-phases produced during craton formation can cause reduction in aggregate shear-wave velocities (VS) at mid-lithospheric depths beneath continents. In addition to the presence of olivine, orthopyroxene, clinopyroxene, and garnet/spinel, phlogopite (Bulk 1: 3-7.6 wt.%; Bulk 2: 2.6-5 wt.%) at 2-4 GPa, and amphibole (Bulk 1: 3-9 wt.%; Bulk 2: 2-6 wt.%) at 2-3 GPa (=1050°C) are also present. Magnesite (Bulk 1: ~1 wt.% and Bulk 2: ~0.6 wt.%) is present at 2-4 GPa (<1000°C at 3 and?100 km depth.
DS1975-0048
1975
Dasgupta, D.R.Chatterjee, P.K., Dasgupta, D.R., Sanya, P.Research Work Done in Petrology and Mineralogy of the Geol.surv. of India Since 1851.India Geological Survey Records, Vol. 100, PT. 2, PP. 39-76.IndiaPetrology, Kimberlite
DS201909-2032
2019
Dasgupta, P.Dasgupta, P., Ray, A., Chakraborti, T.Geochemical characterisation of the Neoarchean newer dolerite dykes of the Bahalda region, Singhbhum craton, Odisha, India: implication for petrogenesis.Journal of Earth Science System, doi:10.1007/s12040- 019-1228-0Indiageochemistry

Abstract: The mafic dyke swarm, newer dolerite dykes (NDDs) intrudes the Archaean Singbhum granite of the Singhbhum craton, eastern India. The present investigation focuses on the petrography and geochemistry of 19 NNE-SSW to NE-SW trending NDDs in two sectors in the northern and south-western part of Bahalda town, Odisha, Singhbhum. Chondrite normalised rare earth element (REE) patterns show light REE (LREE) enrichment among majority of the 13 dykes while the remaining six dykes show a flat REE pattern. Critical analyses of some important trace element ratios like Ba/La, La/Sm, Nb/Y, Ba/Y, Sm/La, Th/La, La/Sm, Nb/Zr, Th/Zr, Hf/Sm, Ta/La and Gd/Yb indicate that the dolerite dykes originated from a heterogeneous spinel peridotite mantle source which was modified by fluids and melts in an arc/back arc setting. REE modelling of these dolerite dykes were attempted on LREE-enriched representative of NDD which shows that these dykes might have been generated by 5-25% partial melting of a modified spinel peridotite source which subsequently suffered around 30% fractional crystallisation of olivine, orthopyroxene and clinopyroxene. The reported age of ~2.75-2.8 Ma seems to be applicable for these dykes and this magmatism appears to be contemporaneous with major scale anorogenic granitic activity in the Singhbhum craton marking a major event of magmatic activity in eastern India.
DS1986-0166
1986
Dasgupta, P.K.Dasgupta, P.K.Picrite bearing mantle xenoliths from Cuddapah Basin, South IndiaIndian Journal of Earth Sciences, Vol. 13, No. 4, October pp. 333-338IndiaBlank
DS200412-0408
2004
Dasgupta, R.Dasgupta, R., Hirschmann, M.M., Withers, A.C.Deep global cycling of carbon constrained by the solidus of anhydrous, carbonated eclogite under upper mantle conditions.Earth and Planetary Science Letters, Vol. 227, 1-2, Oct. 30, pp. 73-85.United States, HawaiiGarnet, pyroxene, carbonated, melting
DS200512-0211
2005
Dasgupta, R.Dasgupta, R., Hirschmann, M.M., Dellas, N.The effect of bulk composition on the solidus of carbonated eclogite from partial melting experiments at 3 GPa.Contributions to Mineralogy and Petrology, Vol. 149, 3, May pp. 288-305.MantleExperimental petrology, eclogites, peridotites, carbonatites
DS200712-0215
2007
Dasgupta, R.Dasgupta, R., Hirschmann, M.M.Effect of variable carbonate concentration on the solidus of mantle peridotite.American Mineralogist, Vol. 92, 2, Feb-Mar. pp. 370-379.MantleCarbonatite
DS200712-0442
2007
Dasgupta, R.Hirschmann, M.M., Dasgupta, R.Carbonatite mantle interaction in the formation of highly alkalic oceanic island basalts.Plates, Plumes, and Paradigms, 1p. abstract p. A408.MantleMelting
DS200812-0264
2008
Dasgupta, R.Dasgupta, R., Walker, D.Carbon solubility in core melts in a shallow magma ocean environment and distribution of carbon between the Earth's core and the mantle.Geochimica et Cosmochimica Acta, Vol. 72, 18, pp. 4627-4641.MantleMelting
DS200912-0153
2009
Dasgupta, R.Dasgupta, R., Hirschmann, M.M., McDonough, W.F., Spiegelman, M., Withers, A.C.Trace element partitioning between garnet lherzolite and carbonatite at 6.6 and 8.6 GPa with application to the geochemistry of the mantle and mantle derived meltsChemical Geology, Vol. 262, 1-2, May 15, pp. 57-77.MantleMelting
DS200912-0302
2009
Dasgupta, R.Hirschmann, M.M., Dasgupta, R.The H/C ratios of Earth's near surface and deep reservoirs, and consequences for deep Earth volatile cycles.Chemical Geology, Vol. 262, 1-2, May 15, pp. 4-16.MantleGeochemistry
DS201112-0236
2011
Dasgupta, R.Dasgupta, R., Tsuno, K., Withers, A.C., Mallik, A.Silicate melting in the Earth's deep upper mantle caused by C-O-H volatiles.Goldschmidt Conference 2011, abstract p.724.MantleCarbonatite
DS201112-0572
2011
Dasgupta, R.Le Roux, V., Dasgupta, R., Le, C.T.A.Mineralogical heterogeneities in the Earth's mantle: constraints from Mn, Co, Ni and Zn partitioning during partial melting.Earth and Planetary Science Letters, Vol. 307, 3-4, pp. 395-408.MantleMineralogy
DS201112-0909
2011
Dasgupta, R.Sanloup, C., Van Westrenen, W., Dasgupta, R., Maynard-Casely, H., Perrillat, J-P.Compressability change in iron-rich melt and implications for core formation models.Earth and Planetary Science Letters, Vol. 306, 1-2, pp. 118-122.MantleMelting
DS201312-0186
2013
Dasgupta, R.Dasgupta, R., Mallik, A., Tsuno, K., Withers, A.C., Hirth, G., Hirschmann, M.M.Carbon dioxide rich silicate melt in the Earth's upper mantle.Nature, Vol. 493, Jan. 10, pp. 211-215.MantleMelting
DS201312-0570
2013
Dasgupta, R.Mallick, A., Dasgupta, R.Reactive infiltration of MORB eclogite derived carbonated silicate melt into fertile peridotite at 3 Gpa and genesis of alkalic magmas.Journal of Petrology, Vol. 54, pp. 2267-2300.MantleAlkaline rocks, magmatism
DS201502-0117
2015
Dasgupta, R.Tsuno, K., Dasgupta, R.Fe Ni Cu C S phase relations at high pressures and temperatures - the role of sulfur in carbon storage and diamond stability at mid to deep upper mantle.Earth and Planetary Science Letters, Vol. 412, pp. 132-142.MantleCarbon
DS201610-1883
2016
Dasgupta, R.Li, Y., Dasgupta, R., Tsuno, K., Monteleone, B., Shimizu, N.Carbon and sulfur budget of the silicate Earth explained by accretion of differentiated planetary embryos.Nature Geoscience, Vol. 9, pp. 781-785.MantleSulfur budgets

Abstract: The abundances of volatile elements in the Earth’s mantle have been attributed to the delivery of volatile-rich material after the main phase of accretion1, 2, 3. However, no known meteorites could deliver the volatile elements, such as carbon, nitrogen, hydrogen and sulfur, at the relative abundances observed for the silicate Earth4. Alternatively, Earth could have acquired its volatile inventory during accretion and differentiation, but the fate of volatile elements during core formation is known only for a limited set of conditions4, 5, 6, 7, 8. Here we present constraints from laboratory experiments on the partitioning of carbon and sulfur between metallic cores and silicate mantles under conditions relevant for rocky planetary bodies. We find that carbon remains more siderophile than sulfur over a range of oxygen fugacities; however, our experiments suggest that in reduced or sulfur-rich bodies, carbon is expelled from the segregating core. Combined with previous constraints9, we propose that the ratio of carbon to sulfur in the silicate Earth could have been established by differentiation of a planetary embryo that was then accreted to the proto-Earth. We suggest that the accretion of a Mercury-like (reduced) or a sulfur-rich (oxidized) differentiated body—in which carbon has been preferentially partitioned into the mantle—may explain the Earth’s carbon and sulfur budgets.
DS201701-0008
2016
Dasgupta, R.Ding, S., Dasgupta, R.The fate of sulfide during decompression melting of peridotite - implications for sulfur inventory of the MORB source depleted upper mantle.Earth and Planetary Science Letters, Vol. 459, pp. 183-195.MantlePeridotite

Abstract: Magmatism at mid ocean ridges is one of the main pathways of S outflux from deep Earth to the surface reservoirs and is a critical step in the global sulfur cycle, yet our understanding of the behavior of sulfide during decompression melting of the upper mantle is incomplete. In order to constrain the sulfur budget of the mantle and reconcile the sulfur and chalcophile element budget of mantle partial melts parental to primitive mid-ocean ridge basalts (MORBs), here we developed a model to describe the behavior of sulfide and Cu during decompression melting by combining the pMELTS thermodynamic model and empirical sulfur contents at sulfide concentration (SCSS) models, taking into account the effect of the presence of Ni and Cu in sulfides on SCSS of mantle-derived melts. Calculation of SCSS along melting adiabat at mantle potential temperature of 1380?°C with variable initial S content in the mantle indicates that the complete consumption or partial survival of sulfide in the melting residue depends on initial S content and degree of melting. Primitive MORBs (Mg# > 60) with S and Cu mostly concentrated in 800-1000 ppm and 80-120 ppm are likely mixture of sulfide undersaturated high degree melts and sulfide saturated low degree melts derived from depleted peridotite containing 100-200 ppm S. Model calculations to capture the effects of variable mantle potential temperatures (1280-1420?°C) indicate that for a given abundance of sulfide in the mantle, hotter mantle consumes sulfide more efficiently than colder mantle owing to the effect of temperature in enhancing sulfide solubility in silicate melt, and higher mantle temperature stabilizing partial melt with higher FeO?FeO? and lower SiO2 and Al2O3, all of which generally enhance sulfide solubility. However, sulfide can still be exhausted by ~10-15%~10-15% melting with bulk S of 100-150 ppm in the mantle when TPTP is as low as 1300?°C. We also show that although variation of View the MathML sourceDCuperidotite/melt and initial Cu in the mantle can all affect the Cu concentration of primitive MORBs, 100-200 ppm S in the MORB source mantle can satisfy both S and Cu geochemistry of partial melts parental to ocean floor basalts.
DS201707-1320
2017
Dasgupta, R.Duncan, M.S., Dasgupta, R.Rise of Earth's atmospheric oxygen controlled by efficient subduction of organic carbon.Nature Geoscience, Vol. 10, 6, pp. 387-392.Mantlesubduction - carbon

Abstract: The net flux of carbon between the Earth’s interior and exterior, which is critical for redox evolution and planetary habitability, relies heavily on the extent of carbon subduction. While the fate of carbonates during subduction has been studied, little is known about how organic carbon is transferred from the Earth’s surface to the interior, although organic carbon sequestration is related to sources of oxygen in the surface environment. Here we use high pressure–temperature experiments to determine the capacity of rhyolitic melts to carry carbon under graphite-saturated conditions in a subducting slab, and thus to constrain the subduction efficiency of organic carbon, the remnants of life, through time. We use our experimental data and a thermodynamic model of CO2 dissolution in slab melts to quantify organic carbon mobility as a function of slab parameters. We show that the subduction of graphitized organic carbon, and the graphite and diamond formed by reduction of carbonates with depth, remained efficient even in ancient, hotter subduction zones where oxidized carbon subduction probably remained limited. We suggest that immobilization of organic carbon in subduction zones and deep sequestration in the mantle facilitated the rise (~103–5 fold) and maintenance of atmospheric oxygen since the Palaeoproterozoic and is causally linked to the Great Oxidation Event. Our modelling shows that episodic recycling of organic carbon before the Great Oxidation Event may also explain occasional whiffs of atmospheric oxygen observed in the Archaean.
DS201809-2104
2018
Dasgupta, R.Tsuno, K., Grewal, D.S., Dasgupta, R.Core mantle fractionation of carbon in Earth and Mars: the effects of sulfur.Geochimica et Cosmochimica Acta, Vol. 238, pp. 477-495.Mantlecarbon

Abstract: Constraining carbon (C) fractionation between silicate magma ocean (MO) and core-forming alloy liquid during early differentiation is essential to understand the origin and early distribution of C between reservoirs such as the crust-atmosphere, mantle, and core of Earth and other terrestrial planets. Yet experimental data at high pressure (P)-temperature (T) on the effect of other light elements such as sulfur (S) in alloy liquid on alloy-silicate partitioning of C and C solubility in Fe-alloy compositions relevant for core formation is lacking. Here we have performed multi-anvil experiments at 6-13?GPa and 1800-2000?°C to examine the effects of S and Ni on the solubility limit of C in Fe-rich alloy liquid as well as partitioning behavior of C between alloy liquid and silicate melt (). The results show that C solubility in the alloy liquid as well as decreases with increasing in S content in the alloy liquid. Empirical regression on C solubility in alloy liquid using our new experimental data and previous experiments demonstrates that C solubility significantly increases with increasing temperature, whereas unlike in S-poor or S-free alloy compositions, there is no discernible effect of Ni on C solubility in S-rich alloy liquid. Our modelling results confirm previous findings that in order to satisfy the C budget of BSE, the bulk Earth C undergoing alloy-silicate fractionation needs to be as high as those of CI-type carbonaceous chondrite, i.e., not leaving any room for volatility-induced loss of carbon during accretion. For Mars, on the other hand, an average single-stage core formation at relatively oxidized conditions (1.0 log unit below IW buffer) with 10-16?wt% S in the core could yield a Martian mantle with a C budget similar to that of Earth’s BSE for a bulk C content of ~0.25-0.9?wt%. For the scenario where C was delivered to the proto-Earth by a S-rich differentiated impactor at a later stage, our model calculations predict that bulk C content in the impactor can be as low as ~0.5?wt% for an impactor mass that lies between 9 and 20% of present day Earth’s mass. This value is much higher than 0.05-0.1?wt% bulk C in the impactor predicted by Li et al. (Li Y., Dasgupta R., Tsuno K., Monteleone B., and Shimizu N. (2016) Carbon and sulfur budget of the silicate Earth explained by accretion of differentiated planetary embryos. Nat. Geosci.9, 781-785) because C-solubility limit of 0.3?wt% in a S-rich alloy predicted by their models is significantly lower than the experimentally derived C-solubility of ~1.6?wt% for the relevant S-content in the core of the impactor.
DS201811-2565
2018
Dasgupta, R.Dasgupta, R., Van Tongeren, J.A., Watson, E.B., Ghiorso, M.Volatile bearing partial melts beneath oceans and continents; where, how much, and of what composition.American Journal of Science, Vol. 318, 1, pp. 141-165.Mantlemelting

Abstract: Besides depth and temperature, CO2 and H2O, are the two most important variables in stabilizing partial melts in the Earth's mantle. However, despite decades of experimental studies on the roles of these two volatile species in affecting mantle melting, ambiguity remains in terms of the stability, composition, and proportion of volatile-bearing partial melts at depths. Furthermore, the difference in the influence of H2O versus CO2 in production of mantle melts is often inadequately discussed. Here I first discuss how as a function of depth and concentration of volatiles, the peridotite + H2O versus peridotite + CO2 near-solidus melting conditions differ - discussing specifically the concepts of saturation of volatile-bearing phases and how the mode of storage of ‘water’ and carbon affects the near solidus melting relations. This analysis shows that for the Earth's mantle beneath oceans and continents, deep, volatile-induced melting is influenced mostly by carbon, with water-bearing carbonated silicate melt being the key agent. A quantitative framework that uses the existing experimental data, allows calculation of the loci, extent of melting, and major element compositions of volatile-bearing partial melts beneath oceans and continents. How the domains of volatile-bearing melt stability are affected when possible oxygen fugacity variation at depths in the mantle is taken into account is also discussed. I show that trace amount hydrous carbonated silicate melt is likely stabilized at two or more distinct depths in the continental lithospheric mantle, at depths ranges similar to where mid-lithospheric discontinuity (MLD) and lithosphere-asthenosphere boundary (LAB) have been estimated from seismology. Whereas beneath oceans, hydrous carbonated silicate melt likely remain continuously stable from the base of the thermal boundary layer to at least 200 km or deeper depending on the prevailing oxygen fugacity at depths. Hotter mantles, such as those beneath oceans, prevent sampling strongly silica-undersaturated, carbonated melts such as kimberlites as shallower basaltic melt generation dominates. Thick thermal boundary layers, such as those in cratonic regions, on the other hand allow production of kimberlitic to carbonatitic melt only. Therefore, the increasing frequency of occurrence of kimberlites starting at the Proterozoic may be causally linked to cooling and growth of sub-continental mantles through time.
DS201811-2568
2018
Dasgupta, R.Eguchi, J., Dasgupta, R.A CO2 solubility model for silicate melts from fluid saturation to graphite or diamond saturation.Chemical Geology, Vol. 487, 1, pp. 23-38.Mantlediamond genesis

Abstract: A model based on a thermodynamic framework for CO2 concentrations and speciation in natural silicate melts at graphite/diamond-saturated to fluid-saturated conditions is presented. The model is simultaneously calibrated with graphite-saturated and fluid-saturated conditions allowing for consistent model predictions across the CCO buffer. The model was calibrated using water-poor (=1?wt% H2O) silicate melts from graphite- to CO2-fluid-saturation over a range of pressure (P?=?0.05-3?GPa), temperature (T?=?950-1600?°C), composition (foidite-rhyolite; NBO?=?0.02-0.92; wt% SiO2?~?39-77, TiO2?~?0.1-5.8, Al2O3?~?7.5-18, FeO?~?0.2-24 MgO?~?0.1-24, CaO?~?0.3-14, Na2O~1-5, K2O?~?0-6), and fO2 (~QFM +1.5 to ~QFM -6). The model can predict CO2 concentrations for a wide range of silicate melt compositions from ultramafic to rhyolitic compositions, i.e., melts that dissolve carbon only as carbonate anions CO32- and those that dissolve carbon both as CO32- and as molecular CO2mol as a function of pressure, temperature, and oxygen fugacity. The model also does a reasonable job in capturing CO2 solubility in hydrous silicate melts with =2-3?wt% H2O. New CO2 solubility experiments at pressures >3?GPa suggest that the newly developed CO2 solubility model can be satisfactorily extrapolated to ~4-5?GPa. Above 5?GPa the model poorly reproduces experimental data, likely owing to structural change in silicate melt at pressures above 5?GPa. An Excel spreadsheet and a Matlab function are provided as online supplementary materials for implementing the new CO2 solubility model presented here.
DS201812-2890
2019
Dasgupta, R.Sun, C., Dasgupta, R.Slab mantle interaction, carbon transport, and kimberlite generation in the deep upper mantle.Earth and Planetary Science Letters, Vol. 506, pp. 38-52.Mantlekimberlite genesis

Abstract: Low-degree partial melts from deeply subducted, carbonated ocean crust are carbonatite liquids with ~35-47 wt% CO2. Their reactions with the overlying mantle regulate the slab-mantle interaction and carbon transport in the deep upper mantle but have not been investigated systematically. Here we present new multi-anvil experiments and parameterized phase relation models to constrain the fate of slab-derived carbonatite melts in the upper mantle. The experiments were conducted at 7 GPa/1400 °C and 10 GPa/1450 °C, and used starting compositions mimicking the ambient mantle infiltrated by variable carbonatite fluxes (0-45 wt%) from the slab surface. Kimberlitic melts (CO2 = 14-32 wt%, SiO2 = 15-33 wt%, and MgO = 20-29 wt%) were produced from experiments with 5.8-25.6 wt% carbonatite influxes. Experimental phase relations demonstrate a reactive melting process in which the carbonatite influx increases in proportion by dissolution of olivine, orthopyroxene, garnet and precipitation of clinopyroxene. This manifests a feasible mechanism for slab-derived carbonatite melts to efficiently transport in the ambient mantle through high-porosity channels. The melt and mineral fractions from this study and previous phase equilibria experiments in peridotite + O systems were empirically parameterized as functions of temperature (900-2000 °C), pressure (3-20 GPa), and bulk compositions (e.g., CO2 = 0.9-17.1 wt% and Na2O + K2O = 0.27-2.51 wt%). Applications of the phase relation models to prescribed melting processes indicate that reactive melting of a carbonatite-fluxed mantle source could produce kimberlitic melts with diverse residual lithologies under various melting conditions. However, reactive melting at the slab-mantle interface can only commence when the slab-released carbonatite melt conquers the carbonation freezing front, i.e., the peridotite solidi suppressed by infiltration of CO2-rich melts in an open system. Depending on temperatures and local influxes, reactive melting and carbonation/redox freezing can occur simultaneously above the slab-mantle interface, yielding heterogeneous lithologies and redox conditions as well as various time-scales of carbon transport in Earth's mantle.
DS201902-0274
2019
Dasgupta, R.Grewal, D.S., Dasgupta, R., Sun, C., Tsuno, K., Costin, G.Delivery of carbon, nitrogen, and sulfur to the silicate Earth by a giant impact.Science Advances, Vol. 5, 1, Jan. 23, 10.1126/sciadv.aau3669 13p.Mantlecrater

Abstract: Earth’s status as the only life-sustaining planet is a result of the timing and delivery mechanism of carbon (C), nitrogen (N), sulfur (S), and hydrogen (H). On the basis of their isotopic signatures, terrestrial volatiles are thought to have derived from carbonaceous chondrites, while the isotopic compositions of nonvolatile major and trace elements suggest that enstatite chondrite-like materials are the primary building blocks of Earth. However, the C/N ratio of the bulk silicate Earth (BSE) is superchondritic, which rules out volatile delivery by a chondritic late veneer. In addition, if delivered during the main phase of Earth’s accretion, then, owing to the greater siderophile (metal loving) nature of C relative to N, core formation should have left behind a subchondritic C/N ratio in the BSE. Here, we present high pressure-temperature experiments to constrain the fate of mixed C-N-S volatiles during core-mantle segregation in the planetary embryo magma oceans and show that C becomes much less siderophile in N-bearing and S-rich alloys, while the siderophile character of N remains largely unaffected in the presence of S. Using the new data and inverse Monte Carlo simulations, we show that the impact of a Mars-sized planet, having minimal contributions from carbonaceous chondrite-like material and coinciding with the Moon-forming event, can be the source of major volatiles in the BSE.
DS201904-0741
2019
Dasgupta, R.Grewal, D.S., Dasgupta, R., Holmes, A.K., Costin, G., Li, Y., Tsuno, K.The fate of nitrogen during core-mantle seperation on Earth.Geochimica et Cosmochimica Acta, Vol. 251. pp. 87-115.Mantlenitrogen

Abstract: Nitrogen, the most dominant constituent of Earth’s atmosphere, is critical for the habitability and existence of life on our planet. However, its distribution between Earth’s major reservoirs, which must be largely influenced by the accretion and differentiation processes during its formative years, is poorly known. Sequestration into the metallic core, along with volatility related loss pre- and post-accretion, could be a critical process that can explain the depletion of nitrogen in the Bulk Silicate Earth (BSE) relative to the primitive chondrites. However, the relative effect of different thermodynamic parameters on the alloy-silicate partitioning behavior of nitrogen is not well understood. Here we present equilibrium partitioning data of N between alloy and silicate melt () from 67 new high pressure (P?=?1-6?GPa)-temperature (T?=?1500-2200?°C) experiments under graphite saturated conditions at a wide range of oxygen fugacity (logfO2?~??IW -4.2 to -0.8), mafic to ultramafic silicate melt compositions (NBO/T?=?0.4 to 2.2), and varying chemical composition of the alloy melts (S and Si contents of 0-32.1?wt.% and 0-3.1?wt.%, respectively). Under relatively oxidizing conditions (~?IW -2.2 to -0.8) nitrogen acts as a siderophile element ( between 1.1 and 52), where decreases with decrease in fO2 and increase in T, and increases with increase in P and NBO/T. Under these conditions remains largely unaffected between S-free conditions and up to ~17?wt.% S content in the alloy melt, and then drops off at >~20?wt.% S content in the alloy melt. Under increasingly reduced conditions (<~?IW -2.2), N becomes increasingly lithophile ( between 0.003 and 0.5) with decreasing with decrease in fO2 and increase in T. At these conditions, fO2 along with Si content of the alloy under the most reduced conditions (<~?IW -3.0), is the controlling parameter with T playing a secondary role, while, P, NBO/T, and S content of the alloy have minimal effects. A multiple linear least-squares regression parametrization for based on the results of this study and previous studies suggests, in agreement with the experimental data, that fO2 (represented by Si content of the alloy melt and FeO content of the silicate melt), followed by T, has the strongest control on . Based on our modeling, to match the present-day BSE N content, impactors that brought N must have been moderately to highly oxidized. If N bearing impactors were reduced, and/or there was significant disequilibrium core formation, then the BSE would be too N-rich and another mechanism for N loss, such as atmospheric loss, would be required.
DS201905-1036
2019
Dasgupta, R.Grewal, D.S., Dasgupta, R., Holems, A.K., Costin, G., Li, Y., Tsuno, K.The fate of nitrogen during core-mantle separation on Earth.Geochimica et Cosmochimica Acta, Vol. 251, pp. 87-115.Mantlenitrogen

Abstract: Nitrogen, the most dominant constituent of Earth’s atmosphere, is critical for the habitability and existence of life on our planet. However, its distribution between Earth’s major reservoirs, which must be largely influenced by the accretion and differentiation processes during its formative years, is poorly known. Sequestration into the metallic core, along with volatility related loss pre- and post-accretion, could be a critical process that can explain the depletion of nitrogen in the Bulk Silicate Earth (BSE) relative to the primitive chondrites. However, the relative effect of different thermodynamic parameters on the alloy-silicate partitioning behavior of nitrogen is not well understood. Here we present equilibrium partitioning data of N between alloy and silicate melt () from 67 new high pressure (P?=?1-6?GPa)-temperature (T?=?1500-2200?°C) experiments under graphite saturated conditions at a wide range of oxygen fugacity (logfO2?~??IW -4.2 to -0.8), mafic to ultramafic silicate melt compositions (NBO/T?=?0.4 to 2.2), and varying chemical composition of the alloy melts (S and Si contents of 0-32.1?wt.% and 0-3.1?wt.%, respectively). Under relatively oxidizing conditions (~?IW -2.2 to -0.8) nitrogen acts as a siderophile element ( between 1.1 and 52), where decreases with decrease in fO2 and increase in T, and increases with increase in P and NBO/T. Under these conditions remains largely unaffected between S-free conditions and up to ~17?wt.% S content in the alloy melt, and then drops off at >~20?wt.% S content in the alloy melt. Under increasingly reduced conditions (<~?IW -2.2), N becomes increasingly lithophile ( between 0.003 and 0.5) with decreasing with decrease in fO2 and increase in T. At these conditions, fO2 along with Si content of the alloy under the most reduced conditions (<~?IW -3.0), is the controlling parameter with T playing a secondary role, while, P, NBO/T, and S content of the alloy have minimal effects. A multiple linear least-squares regression parametrization for based on the results of this study and previous studies suggests, in agreement with the experimental data, that fO2 (represented by Si content of the alloy melt and FeO content of the silicate melt), followed by T, has the strongest control on . Based on our modeling, to match the present-day BSE N content, impactors that brought N must have been moderately to highly oxidized. If N bearing impactors were reduced, and/or there was significant disequilibrium core formation, then the BSE would be too N-rich and another mechanism for N loss, such as atmospheric loss, would be required.
DS201912-2774
2019
Dasgupta, R.Chowdbury, P., Dasgupta, R.Sulfur extraction via carbonated melts from sulfide bearing mantle lithologie - implications for deep sulfur cycle and mantle redox. ( mentions carbonatite and kimberlite)Geochimica et Cosmochimica Acta, in press, 61p. PdfMantlepetrology

Abstract: Transport of sulfur via mantle-derived partial melts from deep Earth to the surface reservoirs is a critical step in the deep global sulfur cycle. Given that sulfur is stored mostly in sulfide phases in mantle lithologies, the critical parameter is sulfur concentration at sulfide saturation (SCSS) of mantle-derived magmas. CO2?±?H2O-induced melting beneath oceanic and continental mantle produces incipient CO2-rich melts. Although, SCSS of silicate melts of a variety of compositions is extensively studied, the SCSS of carbonatitic and carbonated silicate melts have not received much attention. Here we present experiments in graphite capsules at pressures (P) of 2.5-6.0 GPa and temperatures (T) of 1350-1650?°C investigating the SCSS of carbonatitic and carbonated silicate melts. All experiments produced quenched Fe?±?Ni-sulfide melt blobs?+?carbonated melt matrix?±?ol?±?cpx?±?opx?±?gt, with melt composition on a CO2-free basis varying from 7 to 40 wt.% SiO2, 0.5 to 7 wt.% Al2O3, and 9 to 17 wt.% FeO* (total FeO). SCSS measured using EPMA increases with SiO2 and T but is not affected by P; the effect of composition being more pronounced than P-T. The composition of sulfide melt phase also affects SCSS. With increasing Ni in the molten sulfide phase, the SCSS changes from 2000 to 4000?ppm (Ni-free) to is 800-3000?ppm (33 wt.% Ni). Comparison of our measured SCSS with the existing SCSS models for nominally CO2-free silicate melts and with one study for carbonated melts show that these parameterizations fail to capture the sulfide saturation values in CO2-rich melts from our study. Using our new SCSS data and previous SCSS data for melt compositions that span the range from carbonatite to basalts via carbonated silicate melts, we develop a new empirical SCSS parameterization. Unlike a previous model, which suggested SCSS of carbonated melt is only affected by melt FeO* (other than P-T) and did not constrain how SCSS evolves from low-silica carbonatitic melt to low-CO2 basaltic melt, our new parameterization captured complex effects of many melt compositional parameters, including silica on SCSS. Using our new SCSS model, we constrained the efficiency of S extraction from the mantle beneath mid-oceanic ridges and continents via low-degree carbonated melts. Deep carbonated melts beneath ridges are expected to mobilize 5-15% of the initial sulfur before nominally-volatile-free peridotite melting begins. In continental mantle, deep kimberlitic melt can act as an agent to mildly enrich the shallow mantle in sulfide as it evolves to a carbonatitic melt upon reactive cooling. Application of our data to subduction zones suggests that low degree carbonatitic melt is not an efficient agent to extract residual sulfide from the subducting oceanic crust.
DS201912-2820
2019
Dasgupta, R.Saha, S., Dasgupta, R.Phase relations of a depleted peridotite fluxed by CO2-H2O fluid - implications for the stability of partial melts versus volatile bearing mineral phases in the cratonic mantle.Journal of Geophysical Research: Solid Earth, Vol. 124, 10, pp. 10089-10106.Mantleperidotite

Abstract: We present phase-equilibria experiments of a K-bearing, depleted peridotite (Mg# 92) fluxed with a mixed CO2-H2O fluid (0.5 wt.% CO2 and 0.94 wt.% H2O in the bulk) to gain insight into the stability of volatile-bearing partial melts versus volatile-bearing mineral phases in a depleted peridotite system. Experiments were performed at 850-1150 °C and 2-4 GPa using a piston-cylinder and a multianvil apparatus. Olivine, orthopyroxene, clinopyroxene, and spinel/garnet are present at all experimental conditions. Textural confirmation of partial melt is made at temperatures as low as 1000 °C at 2 GPa, 950 °C at 3 GPa, and 1000 °C at 4 GPa marking the onset of melting at 900-1000 °C at 2 GPa, 850-950 °C at 3 GPa, and 950-1000 °C at 3 GPa. Phlogopite and magnesite breakdown at 900-1000 °C at 2 GPa, 950-1000 °C at 3 GPa, and 1000-1050 °C at 4 GPa. Comparison with previously published experiments in depleted peridotite system with identical CO2-H2O content introduced via a silicic melt show that introduction of CO2-H2O as fluid lowers the temperature of phlogopite breakdown by 150-200 °C at 2-4 GPa and stabilizes partial melts at lower temperatures. Our study thus, shows that the volatile-bearing phase present in the cratonic mantle is controlled by bulk composition and is affected by the process of volatile addition during craton formation in a subduction zone. In addition, volatile introduction via melt versus aqueous fluid, leads to different proportion of anhydrous phases such as olivine and orthopyroxene. Considering the agent of metasomatism is thus critical to evaluate how the bulk composition of depleted peridotite is modified, leading to potential stability of volatile-bearing phases as the cause of anomalously low shear wave velocity in mantle domains such as mid lithospheric discontinuities beneath continents.
DS202012-2247
2021
Dasgupta, R.Saha, S., Peng, Y., Dasgupta, R., Mookherjee, M., Fischer, K.M.Assessing the presence of volatile-bearing mineral phases in the cratonic mantle as a possible cause of mid-lithospheric discontinuities.Earth and Planetary Letters, Vol.. 553, 116602, 12p. PdfMantlecratons

Abstract: A number of possible hypotheses have been proposed to explain the origin of mid-lithospheric discontinuities (MLDs), typically characterized by ~2-6% reductions in seismic shear wave velocity (VS) at depths of 60 km to ~150 km in the cratonic sub-continental lithospheric mantle (SCLM). One such hypothesis is the presence of low-shear wave velocity, hydrous and carbonate mineral phases. Although, the presence of hydrous silicates and carbonates can cause a reduction in the shear wave velocity of mantle domains, the contribution of volatile metasomatism to the origins of MLDs has remained incompletely evaluated. To assess the metasomatic origin of MLDs, we compiled experimental phase assemblages, phase proportions, and phase compositions from the literature in peridotite + H2O, peridotite + CO2, and peridotite + H2O + CO2 systems at P-T conditions where hydrous silicate and/or carbonate minerals are stable. By comparing the experimental assemblages with the compiled bulk peridotite compositions for cratons, we bracket plausible proportions and compositions of hydrous silicate and carbonate mineral phases that can be expected in cratonic SCLMs. Based on the CaO and K2O contents of cratonic peridotite xenoliths and the estimated upper limit of CO2 content in SCLM, =~10 vol.% pargasitic amphibole, =~2.1 vol.% phlogopite and =~0.2 vol.% magnesite solid solution can be stable in the SCLM. We also present new elasticity data for the pargasite end member of amphibole based on first principles simulations for more accurate estimates of aggregate VS for metasomatized domains in cratonic mantle. Using the bracketed phase compositions, phase proportions, and updated values of elastic constants for relevant mineral end members, we further calculate aggregate VS at MLD depths for three seismic stations in the northern continental U.S. Depending on the choice of background wave speeds of unmetasomatized peridotite and the cratonic geotherm, the composition and abundance of volatile-bearing mineral phases bracketed here can explain as much as 2.01 to 3.01% reduction in VS. While various craton formation scenarios allow formation of the amphibole and phlogopite abundances bracketed here, presence of volatile-bearing phases in an average cratonic SCLM composition cannot explain the entire range of velocity reductions observed at MLDs. Other possible velocity reduction mechanisms thus must be considered to explain the full estimated range of shear wave speed reduction at MLD depths globally.
DS202012-2252
2020
Dasgupta, R.Sun, C., Dasgupta, R.Thermobarometry of CO2-rich, silica-undersaturated melts constrains cratonic lithosphere thinning through time in areas of kimberlitic magmatism.Earth and Planetary Letters, Vol. 550, 116549, 13p.Global, United States, Wyoming, Canada, Northwest Territories, Europe, Baltic, Indiageothermometry

Abstract: Cratonic lithosphere is believed to have been chemically buoyant and mechanically resistant to destruction over billions of years. Yet the absence of cratonic roots at some Archean terrains casts doubt on the craton stability and longevity on a global scale. As unique mantle-derived melts at ancient continents, silica-poor, kimberlitic melts are ideal tools to constrain the temporal variation of lithosphere thickness and the processes affecting the lithosphere root. However, no reliable thermobarometer exists to date for strongly silica-undersaturated, mantle-derived melts. Here we develop a new thermobarometer for silica-poor, CO2-rich melts using high-temperature, high-pressure experimental data. Our barometer is calibrated based on a new observation of pressure-dependent variation of Al2O3 in partial melts saturated with garnet and olivine, while our thermometer is calibrated based on the well-known olivine-melt Mg-exchange. For applications to natural magmas, we also establish a correction scheme to estimate their primary melt compositions. Applying this liquid-based thermobarometer to the estimated primary melt compositions for a global kimberlite dataset, we show that the equilibration depths between primary kimberlite melts and mantle peridotites indicate a decrease of up to ~150 km in cratonic lithosphere thickness globally during the past ~2 Gyr. Together with the temporal coupling between global kimberlite frequency and cold subduction flux since ~2 Gyr ago, our results imply a causal link between lithosphere thinning and supply of CO2-rich melts enhanced by deep subduction of carbonated oceanic crusts. While hibernating at the lithosphere root, these melts chemically metasomatize and rheologically weaken the rigid lithosphere and consequently facilitate destruction through convective removal in the ambient mantle or thermo-magmatic erosion during mantle plume activities.
DS1990-1333
1990
Dasgupta, S.Sengupta, P., Dasgupta, S., Bhattacharya, P.K., Mukherjee, M.An orthopyroxene-biotite geothermometer and its application in crustal granulites and mantle derived rocksJournal of Metamorphic Geology, Vol. 8, No. 2, March pp. 191-198IndiaMetamorphism, Granulite
DS2003-1532
2003
Dasgupta, S.Yoshida, M., Windley, B.F., Dasgupta, S.Proterozoic East Gondwana: supercontinent assembly and breakupGeological Society of London, Special Publication, No. 206, 472p. $ 183. http://bookshop.geolsoc.org.ukGondwana, RodiniaBook
DS2003-1533
2003
Dasgupta, S.Yoshida, M., Windley, B.F., Dasgupta, S.Proterozoic East Gondwana: super continent assembly and break-upGeological Society of London Special Paper, No. 206, 440p. $280. www.geosoc.orgRodinia, review, Book
DS200412-2187
2003
Dasgupta, S.Yoshida, M., Windley, B.F., Dasgupta, S.Proterozoic East Gondwana: supercontinent assembly and breakup.Geological Society of London, Special Publication, No. 206, 472p. $ 183. http://bookshop.geolsoc.org.ukGondwana, RodiniaTectonics - evolution Book
DS201112-0098
2011
Dasgupta, S.Bose, S., Dunkley, D.J., Dasgupta, S., Das, K., Arima, M.India-Antarctica-Australia-Laurentia connection in the Paleoproterozoic-Mesoproterozoic revisited: evidence from new zircon U Pb and monzazite chemical age dataGeological Society of America Bulletin, Vol. 123, 9/10 pp. 2031-2049.IndiaEastern Ghats Belt, geochronology
DS201710-2255
2017
Dasgupta, S.Pant, N.C., Dasgupta, S.An introduction to the crustal evolution of India and Antarctica: the supercontinent connectionGeological Society of London Special Publication, Vol. 457, pp. 1-6.Indiatectonics
DS1997-0048
1997
Dash, M.R.Asthana, D., Khare, S.K., Dash, M.R.Geochemistry of the Dongargarh volcanic rocks, central India: Implications for Precambrian mantlePrecambrian Research, Vol. 84, No. 1-2, Aug. 1, pp. 105-109IndiaGeochemistry, Volcanics
DS1995-0386
1995
Dash, S.Dash, S.Diamond exploration in Wagrakarur, Anantpur district, Andhra Pradesh, India.Msc Thesis, Indian School Of Mines, IndiaDiamond exploration, Deposit -Wagrakarur
DS1987-0347
1987
Dashdavaa, Z.Kheraskova, T.N., Dashdavaa, Z.Siliceous phosphate explorsion brecciasDoklady Academy of Science USSR, Earth Science Section, Vol. 288, No. 1-6, pp. 62-63RussiaBlank
DS1996-0775
1996
Dashevsk, D.V.Kopylova, M.G., Genshaft, Y.S., Dashevsk, D.V.Petrology of upper mantle and lower crustal xenoliths from the northwesternSpitsbergen.Petrology, Vol. 4, No. 5, Sept-Oct., pp. 493-518.NorwayXenoliths
DS1993-0981
1993
Dashevskaya, D.M.Matveyenkov, V.V., Almukhamedov, A.I., Dashevskaya, D.M.Amphibole pyroxenite xenoliths from the Gorringe Bank (northeasternAtlantic).Doklady Academy of Sciences USSR, Earth Science Section, Vol. 316, No. 3, pp. 99-101.GlobalXenoliths
DS2002-1763
2002
Dashupta, S.Yoshida, M., Dashupta, S.Proterozoic evolution of the northeastern Canadian Shield: lithoprobe eastern Canadian shield onshore-offshore transect ECSOOT - summary.Geological Society of London (U.K.), 440p.$ 183.00 http://bookshop.geolsoc.org.ukGondwanaBook - geology, tectonics
DS200612-0309
2006
Database on Environmental needs for industryDatabase on Environmental needs for industryBest practice information - world wide, updated regularly FREE registerE3 Environmental Excellence in Exploration, e3mining.com or pdac.caGlobalDatabase reminder - Environment - best practice
DS200512-0434
2005
DaterHinze, W.J., Aiken, C., Brozena, J., Coakley, Dater, Flanagan, Forsberg, Hildenbrand, Keller, KelloggNew standards for reducing gravity data: the North American gravity database.Geophysics, Vol. 70, 4, pp. J25-J32.Canada, United StatesGeophysics - gravity
DS2002-0352
2002
Datta, B.Datta, B.Configuration and characterization of the identified kimberlitic bodies in Indravatti basinal area, Bastar District, Chhattisgarh.Records of the Geological Survey of India, Vol. 135, 6, 2000-2001, pp.95-97.India, ChhattisgarhDrilling results
DS200412-0409
2002
Datta, B.Datta, B.Configuration and characterization of the identified kimberlitic bodies in Indravatti basinal area, Bastar District, ChhattisgarRecords of the Geological Survey of India, Vol. 135, 6, 2000-2001, pp.95-97.India, ChhattisgarhDrilling results
DS201811-2576
2018
Datta, S.Gura, C., Kempton, P.D., Datta, S.Geochemistry in the critical zone; limestone shale and kimberlite weathering in the Flint Hills, Kansas. USA.Geological Society of America Annual Meeting, Vol. 50, 4, 1p. AbstractUnited States, Kansaskimberlite

Abstract: The Critical Zone is the realm where rocks meet life. This study examines the physicochemical interactions that occur when interbedded limestone-shale systems and kimberlitc eruptive materials weather to form soils. Fast weathering with extensive soil loss has been a major environmental concern in the Flint Hills. Knowledge of soil formation processes, rates of formation and loss and understanding how these processes differ in different systems are critical for managing soil as a resource. The kimberlites of Riley County, KS, are CO2-rich igneous rocks that are high in Mg and Fe; they are compositionally distinct from the Paleozoic limestones and shales found throughout the rest of the region. Bulk composition and mineralogy of the soils overlying these different bedrock types have been analyzed using X-Ray Fluorescence (XRF), X-Ray diffraction of <2mm soil fraction and <2µm soil clay fraction, bulk elemental extraction, and particle size analyses. Results show that the kimberlitic soils have higher concentrations of Fe, Mg, Ca, K and some trace elements (e.g. Ti, Ni, Cu). The weathering products differ mineralogically as well, e.g. lizardite is abundant in kimberlitic soils and absent from the limestone terrane. As a result, kimberlite-sourced soils have significantly different physical properties than the thin limestone-sourced soils surrounding them. Particle size analysis shows that the limestone-shale soils have a higher proportion of silt-sized particles whereas the kimberlitic soils have more clay (10.55% vs. 8.06%) and significantly more sand (36.12% vs. 14.83%). Mineralogy was determined for all <2mm fractions and for some <2µm soil clay fraction to understand the association and mobility of these major and trace elements in the respective soils. Interestingly some of the similarities between the kimberlite and limestone-shale soils suggests that loess/wind-blown sediment is making a significant contribution to the soil profile. Kimberlite-sourced and limestone-shale-sourced soils produce different weathering products and could potentially have agricultural significance in terms of ionic and nutrient mobility.
DS1981-0128
1981
Datta gupta, S.Datta gupta, S.A Note on the Inclusions of Diamonds from Panna Area, Madhya Pradesh and Jungel Valley, Uttar Pradesh.Indian Minerals, Vol. 35, No. 3, P. 35.India, Madhya Pradesh, Uttar PradeshMineralogy
DS201312-0733
2013
Dattatrayam, R.S.Ravi Kumar, M., Saikia, D., Singh, A., Srinagesh, D., Baidya, P.R., Dattatrayam, R.S.Low shear velocities in the sublithospheric mantle beneath the Indian shield?Journal of Geophysical Research, 50114IndiaTectonics
DS1860-0275
1877
Daubree, A.Descloizeau, A., Daubree, A.Rapport Dur un Memoire de M.s. Meunier Ayant Pout Titre: Composition et Origine du Sable Diamantifere de Dutoitspan Afrique Australe.Academy of Science (PARIS) C.R., Vol. 84, PP. 1124-1130.Africa, South Africa, Cape ProvinceGeology, Mineralogy
DS1860-0262
1876
Daubree, G.A.Daubree, G.A.Association de Platine Avec du DiamantAnnual Mines (PARIS), SER. 7, Vol. 9, P. 130.Africa, South Africa, Cape ProvinceGeology
DS1860-0624
1889
Daubree, G.A.Daubree, G.A.Le Diamant dans L'afrique CentraleJournal of D. SAV. (PARIS), GlobalGeology
DS1860-0656
1890
Daubree, G.A.Daubree, G.A.Causerie Scientifique. Origine du DiamantParis: la Cocarde., MARCH 6TH.GlobalDiamond Genesis
DS1860-0657
1890
Daubree, G.A.Daubree, G.A.Experiences sur les Actions Mecaniques Exercees sur les RochAcademy of Science (PARIS) C.R., Vol. 111, PP. 767-774. PP. 857-863.Africa, South AfricaDiamond genesis, diatremes
DS1860-0658
1890
Daubree, G.A.Daubree, G.A.Analogies de Gisement du Diamant, D'une Part, dans Les Gites de l'afrique Australe; D'autre Part, dans Les Meteorites.Academy of Science (PARIS) C.R., Vol. 110, PP. 18-24.Africa, South Africa, Cape ProvinceMeteorite
DS1860-0696
1891
Daubree, G.A.Daubree, G.A.Recherches Experimentales sur le Role Possible des Gaz a Hautes Temperatures Doues de Tres Fortes Pressions et Animes D'un Mouvement Fort Rapide dans Divers Phenomenes Geologiques.Geological Society FRANCE (PARIS) Bulletin., Vol. 19, PP. 313-354.Africa, South AfricaKimberlite Genesis, Mineralogy
DS1860-0797
1893
Daubree, G.A.Daubree, G.A.Experiences sur Les Actions Mecaniques Exerces sur Les Roches Par des Gaz Douces Tres Fortes Pressions et de Mouvements tress Rapids.Zeitschr. F. Prakt. Geol., PP. 284-295.Africa, South AfricaGeology, Emplacement Of Diatreme
DS200712-0534
2007
Daudi, E.X.E.Key, R.M., Bingen, B., Barton, E., Daudi, E.X.E., Manuel, S., Moniz, A.Kimberlites in a Karoo graben of northern Mozambique: tectonic setting, mineralogy and RbSr geochronology.South African Journal of Geology, Vol. 110, 1, pp. 111-124.Africa, MozambiqueGeochronology
DS1992-1416
1992
Dauev, Yu.M.Sinitsyn, A.V., Dauev, Yu.M., Grib, V.P.Structural setting and productivity of the kimberlites of the Arkhangelsk province #2Russian Geology and Geophysics, Vol. 33, No. 10, pp. 61-70.Russia, Commonwealth of Independent States (CIS), ArkangelskStructure, Kimberlites
DS1992-1417
1992
Dauev, Yu.M.Sinitsyn, A.V., Dauev, Yu.M., Grib, V.P.Structural setting and productivity of the kimberlites of the ArkangelskProvince.Russian Geology and Geophysics, Vol. 33, No. 10, pp. 61-70.Russia, ArkangelskTectonics, Structure
DS1993-0775
1993
Dauev, Yu.M.Kaminsky, F.V., Verzhak, V.V., Dauev, Yu.M., Buima, T., BoukhalfaThe North-African Diamondiferous provinceRussian Geology and Geophysics, Vol. 33, No. 7, pp. 91-95.AlgeriaBled-el-Mas, Alluvial placers
DS1993-0776
1993
Dauev, Yu.M.Kaminsky, F.V., Verzhak, V.V., Dauev, Yu.M., Buima, T., BoukhalfaThe North African Diamondiferous provinceRussian Geology and Geophysics, Vol. 33, No. 7, pp. 82-90GlobalKimberlite
DS1996-0330
1996
Daulton, T.L.Daulton, T.L., Eisenhour, D.D., Buseck, P.R.Genesis of presolar diamonds; comparative high-resolution transmission electron microscopy studyGeochimica et Cosmochimica Acta, Vol. 60, No. 23, Dec. 1, pp. 4853-72.GlobalMicroscopy, Meteorites, Nano-diamonds
DS2003-0879
2003
Dauphas, N.Marty, B., Dauphas, N.The nitrogen record of crust mantle interaction and mantle convection from Archean toEarth and Planetary Science Letters, Vol. 206, No. 3-4, pp. 397-410.MantleConvection
DS200412-0410
2004
Dauphas, N.Dauphas, N., Marty, B.A large secular variation in the nitrogen isotopic composition of the atmosphere since the Archean .. response to a comment on tEarth and Planetary Science Letters, Vol. 225, 3-4, pp. 435-440.MantleGeochronology, nitrogen
DS200912-0154
2009
Dauphas, N.Dauphas, N., Craddock, P.R., Asimow, P.D., Bennett, V.C., Nutman, A.P., Ohnenstetter, D.Iron isotopes may reveal the redox conditions of mantle melting from Archean to present.Earth and Planetary Science Letters, Vol. 288, 1-2, pp. 255-267.MantleRedox
DS201412-0166
2014
Dauphas, N.Dauphas, N., Roskosz, M., Alp, E.E., Neuville, D.R., Hu, M.Y., Sio, C.K., Tissot, F.L.H., Zhao, J., Tissandier, L., Medard, E., Cordier, C.Magma redox and structural controls on iron isotope variations in Earth's mantle and crust.Earth and Planetary Science Letters, Vol. 398, pp. 127-140.MantleRedox
DS201906-1317
2019
Dauphas, N.Liu, J., Wang, W., Yang, H., Wu, Z., Hu, M.Y., Zhao, J., Bi, W., Alp. E.E., Dauphas, N., Liang, W., Chen, B., Lin, J-F.Carbon isotopic signatures of super-deep diamonds mediated by iron redox chemistry.Geochemical Perspectives Letters, Vol. 10, pp. 51-55.Mantleredox

Abstract: Among redox sensitive elements, carbon is particularly important because it may have been a driver rather than a passive recorder of Earth’s redox evolution. The extent to which the isotopic composition of carbon records the redox processes that shaped the Earth is still debated. In particular, the highly reduced deep mantle may be metal-saturated, however, it is still unclear how the presence of metallic phases in?uences the carbon isotopic compositions of super-deep diamonds. Here we report ab initio results for the vibrational properties of carbon in carbonates, diamond, and Fe3C under pressure and temperature conditions relevant to super-deep diamond formation. Previous work on this question neglected the effect of pressure on the equilibrium carbon isotopic fractionation between diamond and Fe3C but our calculations show that this assumption overestimates the fractionation by a factor of ~1.3. Our calculated probability density functions for the carbon isotopic compositions of super-deep diamonds derived from metallic melt can readily explain the very light carbon isotopic compo- sitions observed in some super-deep diamonds. Our results therefore support the view that metallic phases are present during the formation of super-deep diamonds in the mantle below ~250 km.
DS201907-1582
2019
Dauphas, N.Wang, W., Liu, J., Dauphas, N., Yang, H., Wu, Z., Chen, B., Lin, J-F.Carbon isotopic signatures of diamond formation mediated by iron redox chemistry.Acta Geologica Sinica, Vol. 93, 1, p. 174.Mantleredox

Abstract: Diamonds are key messenger from the deep Earth because someare sourced from the longest isolated and deepest accessible regions of the Earth’s mantle. They are prime recorders of the carbon isotopic compositionof the Earth. The C isotope composition (d13C) of natural diamonds showsa widevariationfrom -41‰ to +3‰ with the primary mode at -5 ± 3‰ [1]. In comparison, the d13C values of chondrites and other planetary bodies range between -26‰ and -15‰ [2]. It is possible that some of the low d13C values were inherited from the Earth’s building blocks,but this is unlikely to be the sole explanation for all low d13C values that can reach as low as -41‰. Organic matter at the Earth’s surface that has low d13C values[3] has been regarded as a possible origin for low d13C values. However, organic carbon is usually accompanied by carbonate with higher d13C values (~0 ‰),and it is not clear why this d13C value does not appear frequently in diamonds. Low d13C diamonds were also formed by deposition from C-O-H fluids,but the equilibrium fractionationinvolved between diamonds and fluids issmall at mantle temperatures [1] and the low d13C values of diamonds can only be achieved after extensive Rayleigh distillation. One unique feature of the Earth isactive plate tectonics driven by mantle convection. Relatively oxidized iron and carbon species at the surface, such as carbonate, Fe2+-and Fe3+-bearing silicatesand oxides, are transported to the deep mantle by subducted slabs and strongly involved inthe redox reactions that generatediamonds [4]. The extent to which the isotopic compositionof C duringdiamond formation recordsredox processes that shaped the Earth is still controversial. Here we report onvibration properties of C andFe at high pressure in carbonates, diamond and Fe3C,based on nuclear resonant inelastic X-ray scattering measurements and density functional theory calculationsand further calculate equilibrium C isotope fractionations among these C-bearing species. Our results demonstrate that redox reactions in subducted slabs could generate eclogitic diamonds with d13C values as low as -41‰ if C in diamonds was sourced from the oxidation of a Fe-C liquid. The large C isotopic fractionation and potentially fast separation between diamonds and a Fe-C melt could enable diamond formation as high as 2%with d13C lower than -40‰.
DS1992-0403
1992
Dautel, D.Dupuy, C., Michard, A., Dostal, J., Dautel, D., Baragar, R.A.Proterozoic flood basalts from the Coppermine River area, NorthwestTerritories: isotope and trace element geochemistryCanadian Journal of Earth Sciences, Vol. 29, No. 9, September pp. 1937-1943Northwest TerritoriesBasalts, Geochemistry
DS1995-0465
1995
Dautel, D.Dupuy, C., Micard. A., Dostal, J., Dautel, D., Baragar, W.R.A.Isotope and trace element geochemistry of Proterozoic Natusiak flood basalts from the northwest Canadian ShieldChemical Geology, Vol. 120, No. 1-2, Feb. 1, pp.15-26OntarioGeochemistry, Natusial basalts
DS1990-0919
1990
Dauteria, J.M.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
DS1998-0146
1998
Dauteruil, O.Bourgeois, O., Dauteruil, O., Van Vliet-Lanoe, B.Pleistocene subglacial volcanism in Iceland: tectonic implicationsEarth and Planetary Science Letters, Vol. 164, No.1-2, Dec.15, pp. 165-78.GlobalGeomorphology, Tectonics
DS1993-0316
1993
Dauteuil, O.Dauteuil, O., Brun, J-P.Oblique rifting in a slow spreading ridgeNature, Vol. 361, No. 6408, January 14, pp. 145-148GlobalTectonics, Ridge, rifting
DS201312-0187
2013
Dauteuil, O.Dauteuil, O., Deschamps, F., Bourgeois, O., Mocquet, A., Guillocheau, F.Post breakup evolution and paleotopography of the North Namibia margin during the Meso-Cenozoic.Tectonophysics, Vol. 589, pp. 103-115.Africa, NamibiaTectonics
DS201503-0140
2015
Dauteuil, O.Dauteuil, O., Bessin, P., Guillocheau, F.Topographic growth around the Orange River valley, southern Africa: a Cenozoic record of crustal deformation and climatic change.Geomorphology, Vol. 233, March 15, pp. 5-19.Africa, South AfricaOrange River

Abstract: We reconstruct the history of topographic growth in southern Africa on both sides of the Orange River valley from an integrated analysis of erosion surfaces, crustal deformation and climate change. First, we propose an inventory of erosion surfaces observed in the study area and classify them according to their most likely formative process, i.e. chemical weathering or mechanical erosion. Among the various land units observed we define a new class of landform: the pedivalley, which corresponds to a wide valley with a flat erosional floor. In the Orange River valley, we mapped three low-relief erosion surfaces, each bevelling a variety of lithologies. The oldest and most elevated is (1) a stripped etchplain evolving laterally into (2) a stepped pediplain bearing residual inselbergs; (3) a younger pediplain later formed in response to a more recent event of crustal deformation. These are all Cenozoic landforms: the etchplain is associated with a late Palaeocene to middle Eocene weathering event, and the two pediplains are older than the middle Miocene alluvial terraces of the Orange River. Landscape evolution was first driven by slow uplift (10 m/Ma), followed by a second interval of uplift involving a cumulative magnitude of at least 200 m. This event shaped the transition between the two pediplains and modified the drainage pattern. A final phase of uplift (magnitude: 60 m) occurred after the Middle Miocene and drove the incision of the lower terraces of the Orange River. Climate exerted a major control over the denudation process, and involved very humid conditions responsible for lateritic weathering, followed by more arid conditions, which promoted the formation of pedivalleys. Collectively, these produce pediplains.
DS201801-0020
2018
Dauteuil, O.Guillocheau, F., Simon, B., Baby, G., Bessin, P., Robin, C., Dauteuil, O.Planation surfaces as a record of mantle dynamics: the case of Africa.Gondwana Research, Vol. 53, 1, pp. 82-98.Africageodynamics

Abstract: There are two types of emerged relief on the Earth: high elevation areas (mountain belts and rift shoulders) in active tectonic settings and low elevation domains (anorogenic plateaus and plains) characteristic of the interior of the continents i.e. 70% of the Earth emerged relief. Both plateaus and plains are characterized by large erosional surfaces, called planation surfaces that display undulations with middle (several tens of kilometres) to very long (several thousands of kilometres) wavelengths, i.e. characteristic of lithospheric and mantle deformations respectively. Our objective is here (1) to present a new method of characterization of the very long and long wavelength deformations using planation surfaces with an application to Central Africa and (2) to reconstruct the growth of the very long wavelength relief since 40 Ma, as a record of past mantle dynamics below Central Africa. (i) The African relief results from two major types of planation surfaces, etchplains (weathering surfaces by laterites) and pediplains/pediments. These planation surfaces are stepped along plateaus with different elevations. This stepping of landforms records a local base level fall due to a local tectonic uplift. (ii) Central Africa is an extensive etchplain-type weathering surface - called the African Surface - from the uppermost Cretaceous (70 Ma) to the Middle Eocene (45 Ma) with a paroxysm around the Early Eocene Climatic Optimum. Restoration of this surface in Central Africa suggests very low-elevation planation surfaces adjusted to the Atlantic Ocean and Indian Ocean with a divide located around the present-day eastern branch of the East African Rift. (iii) The present-day topography of Central Africa is younger than 40 -30 Ma and records very long wavelength deformations (1000 -2000 km) with (1) the growth of the Cameroon Dome and East African Dome since 34 Ma, (2) the Angola Mountains since 15 -12 Ma increasing up to Pleistocene times and (3) the uplift of the low-elevation (300 m) Congo Basin since 10 -3 Ma. Some long wavelength deformations (several 100 km) also occurred with (1) the low-elevation Central African Rise since 34 Ma and (2) the Atlantic Bulge since 20 -16 Ma. These very long wavelength deformations record mantle dynamics, with a sharp increase of mantle upwelling around 34 Ma and an increase of the wavelength of the deformation and then of mantle convection around 10 -3 Ma.
DS1997-0242
1997
Dauth, C.Dauth, C.Airborne magnetic, radiometric and satellite imagery for regolith mapping in the Yilgarn CratonExploration Geophysics, (Australian), Vol. 28, No. 1-2, Feb. 1, pp. 199-203Australia, westernGeophysics, Regolith
DS201312-0265
2013
Dautra, J.M.Fernandez, L., Bosch, D., Elmessbahi, H., Bodinier, J.L., Dautra, J.M., Verdoux, P.Lithosphere-asthenosphere interactions (Middle Atlas (Morocco): geochemical highlights.Goldschmidt 2013, AbstractAfrica, MoroccoXenoliths
DS1992-0337
1992
Dautria, J.M.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
DS1995-0131
1995
Dautria, J.M.Bedini, R.M., Bodinier, J.L., Dautria, J.M., Morten, L.Superimposed metasomatic processes in lithospheric mantle beneath East African Rift: a single melt sourceProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 44-46.GlobalMetasomatism, Xenoliths
DS1998-0099
1998
Dautria, J.M.Bedini, R.M., Bodinier, J.L., Dautria, J.M., Morten, L.Evolution of large-ion lithophile elements (LILE) enriched small melt fractions in the lithospheric mantle:case study from East African Rift.Earth and Planetary Science Letters, Vol. 153, No. 1-2, pp. 67-83.GlobalEast African Rift, Tectonics, Mantle peridotites
DS1996-0675
1996
Dautria, J-M.Jakni, B., Dautria, J-M., Liotard, J-M., Brigueu, L.Evidence of the presence of a carbonated mantle beneath Bas-Languedoc:peridotitic xenoliths Grand Magnon...C.r. Academy Of Science Paris., *french, Vol. 323, iia, pp. 33-40.FranceXenoliths, Basanites, Leucito-nephelinites
DS2000-0567
2000
Dautria, J-M.Lenoir, X., Garrido, C.J., Bodinier, J.L., Dautria, J-M.Contrasting lithospheric mantle domains beneath the Massif Central revealed by geochemistry peridotite...Earth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.359-75.FranceXenoliths - geochemistry
DS200712-0604
2007
Dautria, J-M.Le Roux, V., Bodinier, J-L., Tommasi, A., Alard, O., Dautria, J-M., Vauchez, A., Riches, A.J.V.The lherz spinel lherzolite: refertilized rather than pristine mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 599-612.MantleLherzolite chemistry
DS200712-0605
2007
Dautria, J-M.Le Roux, V., Bodinier, J-L., Tommasi, A., Alard, O., Dautria, J-M., Vauchez, A., Riches, A.J.V.The lherz spinel lherzolite: refertilized rather than pristine mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 599-612.MantleLherzolite chemistry
DS201412-0478
2014
Dautria, J-M.Kourim, F., Bodinier, J-L., Alard, O., Bendaoud, A., Vauchez, A., Dautria, J-M.Nature and evolution of the lithospheric mantle beneath the Hoggar Swell ( Algeria): a record from mantle xenoliths.Journal of Petrology, Vol. 55, pp. 2249-2280.Africa, AlgeriaXenoliths
DS201904-0744
2019
Dautria, J-M.Hidas, K., Garrido, C.J., Booth-Rea, G., Marchesi, C., Bodinier, J-L., Dautria, J-M., Louni-Hacini, A., Azzouni-Sekkal, A.Lithosphere tearing along STEP faults and synkenetic formation of lherzolite and wehrlite in the shallow subcontinental mantle. OranSolid Earth, https://doi.org/10.5194 /se-2019-32 36p.Mantle, Africa, Algeriasubduction

Abstract: Subduction-Transform Edge Propagator (STEP) faults are the locus of continual lithospheric tearing at slab edges, resulting in sharp changes in the lithospheric and crustal thickness and triggering lateral and/or near-vertical mantle flow. However, the mechanisms at the lithospheric mantle scale are still poorly understood. Here, we present the microstructural study of olivine-rich lherzolite, harzburgite and wehrlite mantle xenoliths from the Oran volcanic field (Tell Atlas, NW Algeria). This alkali volcanic field occurs along a major STEP fault responsible for the Miocene westward slab retreat in the westernmost Mediterranean. Mantle xenoliths provide a unique opportunity to investigate the microstructures in the mantle section of a STEP fault system. The microstructures of mantle xenoliths show a variable grain size ranging from coarse granular to fine-grained equigranular textures uncorrelated with modal variations. The major element composition of the mantle peridotites provides temperature estimates in a wide range (790-1165?°C) but in general, the coarse-grained and fine-grained peridotites suggest deeper and shallower provenance depth, respectively. Olivine grain size in the fine-grained peridotites depends on the size and volume fraction of the pyroxene grains, which is consistent with pinning of olivine grain growth by pyroxenes as second phase particles. In the coarse-grained peridotites, well-developed olivine crystal preferred orientation (CPO) is characterized by orthorhombic and [100]-fiber symmetries, and orthopyroxene has a coherent CPO with that of olivine, suggesting their coeval deformation by dislocation creep at high-temperature. In the fine-grained microstructures, along with the weakening of the fabric strength, olivine CPO symmetry exhibits a shift towards [010]-fiber and the [010]- and [001]-axes of orthopyroxene are generally distributed subparallel to those of olivine. These data are consistent with deformation of olivine in the presence of low amounts of melts and the precipitation of orthopyroxenes from a melt phase. The bulk CPO of clinopyroxene mimics that of orthopyroxene via a topotaxial relationship of the two pyroxenes. This observation points to a melt-related origin of most clinopyroxenes in the Oran mantle xenoliths. The textural and geochemical record of the peridotites are consistent with interaction of a refractory harzburgite protolith with a high-Mg# melt at depth (resulting in the formation of coarse-grained clinopyroxene-rich lherzolite and wehrlite), and with a low-Mg# evolved melt in the shallow subcontinental lithospheric mantle (forming fine-grained harzburgite). We propose that pervasive melt-peridotite reaction - promoted by lateral and/or near-vertical mantle flow associated with lithospheric tearing - resulted in the synkinematic crystallization of secondary lherzolite and wehrlite and played a key effect on grain size reduction during the operation of the Rif-Tell STEP fault. Melt-rock reaction and secondary formation of lherzolite and wehrlite may be widespread in other STEP fault systems worldwide.
DS200612-0346
2006
Davaadorj, T.Dorjnamjaa, D., Tomurkhuu, D., Davaadorj, T.The geotectonic evolution and metallogeny of Mongolia during the Precambrian Phanerozoic time.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.Asia, MongoliaTectonics
DS201506-0259
2015
DavailleCondie, K., Davaille, AsterUpstairs - downstairs: supercontinents and large igneous provinces, are they related?International Geology Review, Vol. 57, 11-12, pp. 1341-1348.MantleSupercontinents

Abstract: There is a correlation of global large igneous province (LIP) events with zircon age peaks at 2700, 2500, 2100, 1900, 1750, 1100, and 600 and also probably at 3450, 3000, 2000, and 300?Ma. Power spectral analyses of LIP event distributions suggest important periodicities at 250, 150, 100, 50, and 25?million years with weaker periodicities at 70-80, 45, and 18-20?Ma. The 25?million year periodicity is important only in the last 300?million years. Some LIP events are associated with granite-forming (zircon-producing) events and others are not, and LIP events at 1900 and 600?Ma correlate with peaks in craton collision frequency. LIP age peaks are associated with supercontinent rifting or breakup, but not dispersal, at 2450-2400, 2200, 1380, 1280, 800-750, and =200?Ma, and with supercontinent assembly at 1750 and 600?Ma. LIP peaks at 2700 and 2500?Ma and the valley between these peaks span the time of Neoarchaean supercraton assemblies. These observations are consistent with plume generation in the deep mantle operating independently of the supercontinent cycle and being controlled by lower-mantle and core-mantle boundary thermochemical dynamics. Two processes whereby plumes can impact continental assembly and breakup are (1) plumes may rise beneath supercontinents and initiate supercontinent breakup, and (2) plume ascent may increase the frequency of craton collisions and the rate of crustal growth by accelerating subduction.
DS1995-0387
1995
Davaille, A.Davaille, A.Is the mantle stratified? Yes and no depending on the heterogeneities ofwavelength.Eos, Vol. 76, No. 46, Nov. 7. p.F578. Abstract.MantleGeophysics -seismic, Layering
DS1998-0688
1998
Davaille, A.Jaupert, C., Mareschal, J.C., Davaille, A.Heat flow and thickness of the lithosphere in the Canadian ShieldJournal of Geophysical Research, Vol. 103, No. 7, Jul. 10, pp. 15269-86.Northwest Territories, Manitoba, Saskatchewan, AlbertaHeat flow, Mantle
DS2002-0353
2002
Davaille, A.Davaille, A., Girard, F., Le Bars, M.How to anchor hotspots in a convecting mantle?Earth and Planetary Science Letters, Vol. 203, 3, pp. 621-34.MantleHot spots, Convection - model
DS2003-0291
2003
Davaille, A.Courtillot, V., Davaille, A., Besse, J., Stock, J.Three distinct types of hotspots in the Earth's mantleEarth and Planetary Science Letters, Vol. 205, 3-4, pp. 295-308.MantlePlumes, Geothermometry
DS2003-0311
2003
Davaille, A.Davaille, A., Le Bars, M., Carbonne, C.Thermal convection in a heterogeneous mantleComptes Rendus Geoscience, Vol. 335, 1, pp. 141-156.MantleGeothermometry
DS200412-0411
2004
Davaille, A.Davaille, A., Lees, J.M.Thermal modeling of subducted plates: tear and hotspot at the Kamchatka corner.Earth and Planetary Science Letters, Vol. 226, 3-4, Oct. 15, pp. 293-304.RussiaGeophysics - seismics, dynamics, hotpots, lithosphere
DS200412-1089
2004
Davaille, A.Le Bars, M., Davaille, A.Whole layer convection in a heterogeneous planetary mantle.Journal of Geophysical Research, Vol. 109, 3, DOI 10.1029/2003 JB002617MantleStratigraphy
DS200512-0212
2005
Davaille, A.Davaille, A., Vatteville, J.On the transient nature of mantle plumes.Geophysical Research Letters, Vol. 32, 14, July 28, L14309MantleTectonics
DS200712-0584
2007
Davaille, A.Kumagi, I., Davaille, A., Kurita, K.On the fate of thermally bouyant mantle plumes at density interfaces.Earth and Planetary Science Letters, Vol. 254, 1-2, Feb. 15, pp. 180-193.MantleHotspots
DS200812-0615
2008
Davaille, A.Kumagai, I., Davaille, A., Kunta, K., Stutzmann, E.Mantle plumes: thin, fat, successful or failing? Constraints to explain hot spot volcanism through time and space.Geophysical Research Letters, Vol. 35, 16, L16301.MantlePlume
DS201412-0138
2014
Davaille, A.Condie, K., Davaille, A.Mantle plumes and the supercontinent cycle.GAC-MAC Annual Meeting May, abstract 1p.MantlePlume
DS201412-0140
2015
Davaille, A.Condie, K.C., Davaille, A., Aster, R.C., Arndt, N.Upstairs-downstairs: supercontinents amd large igneous provinces, are they related?International Geology Review, Vol. 57, 11-12, pp. 1341-1348.GlobalSupercontinents
DS201707-1316
2017
Davaille, A.Condie, K., Arndt, N., Davaille, A., Puetz, S.J.Zircon age peaks: production or preservation of continental crust?Geosphere, Vol. 10, 6, pp. 397-398.Mantlegeochronology

Abstract: Zircon age peaks are commonly interpreted either as crustal production peaks or as selective preservation peaks of subduction-produced crust selectively preserved during continent-continent collision. We contribute to this ongoing debate, using the Nd isotopic compositions of felsic igneous rocks and their distribution during the accretionary and collisional phases of orogens. The proportion of juvenile input into the continental crust is estimated with a mixing model using arc-like mantle and reworked continental crust end members. Orogen length and duration proxies for juvenile crustal volume show that the amount of juvenile crust produced and preserved at zircon age peaks during the accretionary phase of orogens is =3 times that preserved during the collisional phase of orogens. The fact that most juvenile crust is both produced and preserved during the accretionary phase of orogens does not require craton collisions for its preservation, thus favoring the interpretation of zircon age peaks as crustal production peaks. Most juvenile continental crust older than 600 Ma is produced and preserved before final supercontinent assembly and does not require supercontinent assembly for its preservation. Episodic destabilization of a compositionally heterogeneous layer at the base of the mantle may produce mantle plume events leading to enhanced subduction and crustal production. Our Nd isotope model for cumulative continental growth based on juvenile crust proxies for the past 2.5 b.y. suggests a step-like growth curve with rapid growth in accretionary orogens at the times of zircon age peaks.
DS201806-1217
2018
Davaille, A.Condie, K.C., Puetz, S.J., Davaille, A.Episodic crustal production before 2.7 Ga.Precambrian Research, Vol. 312, pp. 16-22.Mantlegeochronology - zircon

Abstract: Before 2.7?Ga, 14 igneous and detrital zircon age peaks and 9 large igneous province (LIP) age peaks are robust and statistically significant. Correlation analysis indicates a synchronous association among these peaks and power spectral analysis shows 91, 114-127 and 182-Myr cycles. These age cycles may be related to mantle plume or mantle overturn events, and to the time it takes to reach threshold temperature gradients for thermo-chemical destabilization in the lowermost mantle. Most zircon age peaks are transferred into younger detrital sediments, which does not favor an origin of the peaks by selective erosion. Correlation of eight pre-2.7-Ga LIP age peaks with zircon age peaks is consistent with a genetic relationship between mantle melting events and felsic crustal production and supports an interpretation of pre-2.7-Ga age peaks as growth rather than preservation peaks produced during craton collisions. Also consistent with the growth peak interpretation is the apparent absence of collisional orogens older than 2.7?Ga. An increasing number of geographic age peak sites from 4 to 2.8?Ga suggests production and survival of only small volumes of continental crust during this time and supports an episodic model for continental crustal growth.
DS202010-1836
2020
Davaille, A.Davaille, A., Romanowicz, B.Deflating the LLSVPs: bundles of mantle thermochemical plumes rather than thick stagnant "piles".Tectonics, e202TC006265 Vol. 39, 4, ? Mantletomography

Abstract: Based on SEMUCB-WM1 tomographic model, validated by other recent models, and fluid mechanics constraints, we show that the large low shear velocity provinces (LLSVPs) present at the base of the Earth's mantle beneath the Pacific and Africa do not extend as compact, uniform structures very high above the core-mantle boundary. In contrast, they contain a number of well-separated, low-velocity conduits that extend vertically throughout most of the lower mantle. The conceptual model of compact piles, continuously covering the areal extent of the LLSVPs, is therefore not correct. Instead, each LLSVP is composed of a bundle of thermochemical upwellings probably enriched in denser than average material. It is only when the tomographic model is filtered to long wavelengths that the two bundles of plumes appear as uniform provinces. Furthermore, the overall shape of the LLSVPs is probably controlled by the distribution of subducted slabs, and due to their thermochemical nature, the position of both LLSVPs and individual upwelling dynamics should be time dependent. There is also evidence for smaller plumes originating near the CMB in the faster than average regions of the voting map of Lekic et al. (2012, https://doi.org/10.1016/j.epsl.2012.09.014) as well as other, barely resolved, weaker plumes within the LLSVPs. These finer-scale features are starting to be resolved tomographically owing to improvements in full waveform modeling of body waves, including diffracted S waves (Sdiff) and waves multiply reflected on the core-mantle boundary (ScS) and their codas.
DS2000-1029
2000
Davaney, J.R.Wyman, D.A., Ayer, J.A., Davaney, J.R.Niobium enriched basalts from the Wabigoon subprovince: evidence for adakritic metasomatism above subduction..Earth and Planetary Science Letters, Vol. 179, No. 1, June 15, pp. 21-30.OntarioSubduction zone
DS201612-2292
2016
Dave, R.Dave, R., Li, A.Destruction of the Wyoming craton: seismic evidence and geodynamic processes.Geology, Vol. 44, 11, pp. 883-886.United States, Wyoming, Colorado PlateauWyoming craton - kimberlites

Abstract: Cratons are old and strong continental cores where the lithosphere is thick and remains largely undeformed for 2-3 b.y. Unlike typical cratons, the Wyoming craton underwent pervasive deformation ca. 80-55 Ma during the Laramide orogeny in the west-central United States, and has been subsequently encroached upon by the Yellowstone hotspot since 2.0 Ma. However, the mechanism for the deformation and the craton-hotspot interaction are not well understood. We present here a three-dimensional shear wave velocity model beneath the Wyoming craton constrained from Rayleigh wave data, which reveal new details about the cratonic lithosphere. The average lithosphere thickness beneath the craton is ~150 km, significantly thinner than a normal cratonic root (>200 km). Continuous low velocities are observed beneath the Yellowstone hotspot and the Cheyenne belt. A low-velocity column is also present in the central-eastern craton at depths of 115-250 km. These low velocities can be explained by hot temperature and partial melting, implying mantle upwelling. A high-velocity anomaly with a dripping shape in central Wyoming extends to 200-250 km depth, indicating mantle downwelling and lithosphere erosion. Our model provides the first seismic evidence for complex small-scale mantle convection beneath the Wyoming craton. The convection probably developed during the subduction of the Farallon plate and has been reinforced by the Yellowstone hotspot. We propose that the combination of flat-slab subduction, small-scale convection, and hotspot activity can lead to massive destruction of a cratonic lithosphere.
DS1993-0317
1993
Davenport, P.H.Davenport, P.H.Geochemical baseline versus backgroundExplore, No. 78, January pp. 7-10GlobalGeochemistry, Geochemical mapping
DS201809-2014
2018
Daver, L.Daver, L., Bureau, H., Gaillou, E., Ferraris, C., Bouillard, J-C., Cartigny, P., Pinti, D.L.In situ analysis of inclusions in diamonds from collections.Goldschmidt Conference, 1p. AbstractGlobaldiamond inclusions

Abstract: Diamonds represent one of the few witnesses of our planet interior. They are mainly formed in the first 200 km of the lithospheric mantle, and, more rarely from the transition zone to 700 km deep. Diamonds contain a lot of information about global evolution, however their mode of formation remains poorly understood. Recent studies in high-pressure mineralogy suggest that diamonds precipitate from oxidized metasomatic fluids. The study of inclusions trapped in diamonds may provide precise information on composition, pressure, temperature and redox conditions. The aim of this study is to use the inclusions trapped in diamond as probes of the deep cycling of volatiles (C, H, halogens). Therefore, we investigate inclusions in diamonds with a systematic study of diamonds from collections. We selected 73 diamonds from three museums: National Museum of Natural History, School of Mines and Sorbonne University. The selected diamonds are studied with the help of a large range of in situ methods: RAMAN and FTIR spectrometry and X-Ray Diffraction. These analyses allow us to identify the nature of the different inclusions without damaging the gems. First results indicate silicate minerals inclusions as pyrope garnet, olivine and enstatite pyroxene. This assemblage is typical of peridotitic-type diamonds in the lithosphere.
DS202006-0916
2020
Davey, S.C.Davey, S.C., Bleeker, W., Kamo, S.L., Vuollo, J., Ernst, R.E., Cousens, B.L.Archean block rotation in western Karelia: resolving dyke swarm patterns in metacraton Karelia-Kola for a refined paleogeographic reconstruction of supercraton Superia.Lithos, in press available 95p. PdfRussia, Kola Peninsulacraton

Abstract: Rifting, breakup, and subsequent collision related to the ca. 1.92-1.79?Ga Svecofennian orogeny fragmented and deformed the western margin of the Archean Karelia-Kola craton into four crustal blocks: Pudasjärvi, Iisalmi, Kuhmo, and Taivalkoski. Detailed quantification of Svecofennian deformation is limited due to poorly exposed basement geology and an as yet incomplete dyke swarm record. New U-Pb ID-TIMS geochronological results on baddeleyite and zircon are presented for three key mafic dykes from the Pudasjärvi block, namely the Uolevinlehto, Myllykangas, and Sipojuntti dykes. The age of the 325°-trending Uolevinlehto dyke is estimated at ca. 2400?±?12?Ma from discordant multigrain baddeleyite fractions, showing it to be younger than ca. 2450?Ma dykes across Karelia. The 350°-trending Myllykangas dyke has a minimum age of 2135.2?+?3.6/-3.7?Ma based on chemically abraded zircon. Results from single baddeleyite grains provide a precise upper intercept age of 2128.9?±?1.2?Ma for the 320°-trending Sipojuntti dyke. Our new U-Pb ages are integrated with those from the literature to define six major dyke swarms in the Pudasjärvi block: the WNW-trending ca. 2.45?Ga Pääjärvi, NW-trending ca. 2.40?Ga Uolevinlehto, NW-trending ca. 2.13-2.10?Ga Tohmajärvi, WNW-trending ca. 2.07?Ga Palomaa, NNW-trending ca. 1.98?Ga Paukkajanvaara and undated"East-West" dykes. Trends of contemporaneous dyke swarms in the Taivalkoski and Kuhmo blocks, however, are systematically offset by 35°. With subvertical dips, offset dyke swarms record 35° clockwise vertical-axis rotation of the Pudasjärvi block relative to the interior of Karelia, consistent with dextral transpression during the Svecofennian orogeny. Structural restoration of the Pudasjärvi blocks improves the constraints on regional dyke swarm patterns, and these are used to revise the position of the Karelia-Kola craton within the context of the paleogeographic reconstruction of supercraton Superia.
DS1993-0948
1993
DavidMachado, N., David, Scott, Lamothe, Philipe, Gariepyuranium-lead (U-Pb) geochronology of the western Cape Smith Belt: new insights on age of initial rifting and arc magmatismGeological Association of Canada (GAC), Annual Meeting, Vol. 16, p. A78. abstract.Quebec, Ungava, LabradorGeochronology, Tectonics
DS1994-1923
1994
DavidWilliamson, DavidRedaurum Red Lakes Mines Ltd. Diamond production and highly prospective exploration projects in Zimbabwe.David Williamson Associates Limited, 8p.ZimbabweNews item -research report, Redaurum
DS1997-0912
1997
DavidPilote, P., Dion, C., Joanisse, David, Machado, KirkhaM.Geochronologie des mineralisations d'affiliation magmatique de l'Abitibi -implications geotectoniques.Quebec Department of Mines, DV97-03, p. 47.QuebecGeochronology, Magmatism - not specifc to diamonds
DS2000-0950
2000
DavidTelmat, H., Mareschal, Gariepy, David, AntonukCrustal models of the eastern Superior Province, Quebec, derived from new gravity data.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.385-97.QuebecGeophysics - gravity, Tectonics - Superior
DS2001-0667
2001
DavidLeclair, A.D., Berclaz, David, Percival, J.Regional geological setting of Archean rocks in the northeastern Superior Province.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.84.abstract.Quebec, UngavaGeology - brief overview
DS1860-0244
1875
David, A.David, A.Existence of Diamonds Reported Ki-ming-chauNouvelles Archives Du Musee, De L'histoire Naturelle De Pari, China, PekingDiamond Occurrence
DS200712-0216
2006
David, C.David, C., Collins, A.T., Martineau, P.Defects in single crystal CVD synthetic diamond studied by optical spectroscopy with the application of uniaxial stress.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.121-2, abstract onlyTechnologyCVD diamond
DS1996-0331
1996
David, D.David, D.HMS cyclone development at Argyle diamondsAusIMM Conference held March 24-26, Perth, pp. 265-273.AustraliaMineral processing - cyclone, Deposit - Argyle
DS201804-0681
2018
David, E.C.Cline, C.J. II, Faul, U.H., David, E.C., Berry, A.J., Jackson, I.Redox influenced seismic properties of upper mantle olivine.Nature, Vol. 555, March 15, pp. 255-258.Mantlegeophysics - seismics

Abstract: Lateral variations of seismic wave speeds and attenuation (dissipation of strain energy) in the Earth’s upper mantle have the potential to map key characteristics such as temperature, major-element composition, melt fraction and water content1,2,3. The inversion of these data into meaningful representations of physical properties requires a robust understanding of the micromechanical processes that affect the propagation of seismic waves2,3. Structurally bound water (hydroxyl) is believed to affect seismic properties2,3 but this has yet to be experimentally quantified. Here we present a comprehensive low-frequency forced-oscillation assessment of the seismic properties of olivine as a function of water content within the under-saturated regime that is relevant to the Earth’s interior. Our results demonstrate that wave speeds and attenuation are in fact strikingly insensitive to water content. Rather, the redox conditions imposed by the choice of metal sleeving, and the associated defect chemistry, appear to have a substantial influence on the seismic properties. These findings suggest that elevated water contents are not responsible for low-velocity or high-attenuation structures in the upper mantle. Instead, the high attenuation observed in hydrous and oxidized regions of the upper mantle (such as above subduction zones) may reflect the prevailing oxygen fugacity. In addition, these data provide no support for the hypothesis whereby a sharp lithosphere-asthenosphere boundary is explained by enhanced grain boundary sliding in the presence of water.
DS201112-0238
2011
David, F.A.David, F.A., Hirschmann, M.M., Humayun, M.The composition of the incipient partial melt of garnet peridotite at 3 GPa and the origin of OIB.Earth and Planetary Science Letters, Vol. 308, 3-4, pp. 380-390.MantleMelting
DS1997-0243
1997
David, G.A.David, G.A.Effect of Nafta on the economics of mineral productionMining Engineering, Vol. 49, No. 9, September pp. 57-61GlobalEconomics, Mineral industries
DS1997-0710
1997
David, J.Machado, N., Clark, T., David, J., Goulet, N.uranium-lead (U-Pb) ages for magmatism and deformation in the New Quebec OrogenCanadian Journal of Earth Sciences, Vol. 34, pp. 716-23.Quebec, Labrador, UngavaMagmatism, Orogeny - New Quebec
DS1998-1459
1998
David, J.Telmat, H., Mareschal, J.C., Gariepy, C., David, J.Crustal models of the northern Superior Province, Quebec, derived from new gravity data.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A183. abstract.QuebecGeophysics - gravity, Nemiscau, la Grande regions
DS2002-0161
2002
David, J.Bizarro, M., Simonetti, A., Stevenson, R.K., David, J.Hf isotope evidence for a hidden mantle reservoirGeology, Vol. 30,9,Sept. pp. 771-4.Greenland, North America, LabradorCarbonatite, kimberlites, Archean - geochronology
DS2002-0162
2002
David, J.Bizzarro, M., Simonetti, A., Stevenson, R.K., David, J.Hf isotope evidence for a hidden mantle reservoirGeology, Vol. 30, 9, Sept. pp. 771-4.MantleGeochronology
DS200612-1374
2006
David, J.Stevenson, R.K., David, J., Parent, M.Crustal evolution of the western Minto Block, northern Superior Province, Canada.Precambrian Research, Vol.145, 3-4 March 30, pp.229-242.Canada, QuebecCrustal evolution, geochronology - not specific diamond
DS1998-0916
1998
David, K.Madhaven, V., David, K., Srinivas, M.Comparative study of lamprophyres from the Cuddapah Intrusive province(CIP) Andhra Pradesh, India.Journal of Geological Society India, Vol. 52, No. 6, Dec. pp. 621-42.India, South IndiaLamprophyres, Deposit - Elchuru, Purimetla, PrakasaM.
DS2000-0207
2000
David, K.David, K., Schiano, P., Allegre, C.J.Assessment of the Zirconium and Hafnium fractionation in oceanic basalts and continental materials during petrogenetic..Earth and Planetary Science Letters, Vol. 178, No. 3-4, May 30, pp. 285-302.GlobalMagmatism, Petrogenesis
DS1989-0330
1989
David, M.David, M., Toh, E.Grade control problems dilution and geostatistics:choosing the required quality and number of samples for grade controlThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 82, No. 931, November pp. 53-60GlobalGeostatistics, Grade control
DS1991-1255
1991
David, M.Olea, R.A., Christakos, G., David, M., Journel, A.G., Krige, D.G.Geostatistical glossary and multilingual dictionaryOxford University of Press, 288p. $ 55.95 approxGlobalGeostatistics -glossary
DS1989-0880
1989
David, T.A.Lewchuk, M.T., David, T.A.Age and petrogenesis of the middle Proterozoic Coldwell Complex of Ontario from paleomagntisM.Geological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A109. (abstract.)OntarioMid continent, Kapuskasing Lithoprobe
DS1900-0399
1906
David, T.W.E.David, T.W.E.Occurrence of Diamonds in Matrix at Pike and O'donnells Claims, Oakey Creek, Near Inverell, New South Wales.International Geological Congress 10TH., PP. 1202-1210.Australia, New South WalesKimberlite, Non-kimberlitic Source Rock
DS1900-0400
1906
David, T.W.E.David, T.W.E.The Origin and Occurrence of the Diamond (1906)Chemical News, Vol. 96, PP. 140-142. ALSO: The Mining Journal Vol. 72, PP.GlobalGenesis, Diamond Occurrences
DS1900-0543
1907
David, T.W.E.David, T.W.E.An Occurrence of Diamonds in Matrix at Oakey Creek Near Inverell, New South Wales.British Association Advanced Science, Report For The 76th. Meeting, Held, PP. 562-563.AustraliaKimberlite, Non-kimberlitic Source Rock
DS1900-0544
1907
David, T.W.E.David, T.W.E.The Origin and Occurrence of the Diamond (1907)Chemical News, Vol. 96, PP. 140-142. ALSO: The Mining Journal R. and COM.GlobalDiamond Genesis
DS1900-0545
1907
David, T.W.E.David, T.W.E.The Origin and Occurrences of DiamondChemical News, Vol. 96, No. 2495, SEPT. 20TH. PP. 140-142.Africa, South AfricaGenesis, Origin
DS201112-0237
2010
David Pescod's StocktalkDavid Pescod's StocktalkAn interview with Eric Friedland CEO with Peregrine Diamonds.debbie.lewis @ canaccord.com, Dec. 13, 2p.Canada, Nunavut, Baffin IslandNews item - Peregrine
DS201112-1073
2011
Davidheiser, B.Van der Meer, Q.H.A., Klaver, M., Reisberg, L., Davidheiser, B., Davies, G.R.The age and origin of the Limpopo sub-continental lithospheric mantle.Goldschmidt Conference 2011, abstract p.2064.Africa, South AfricaVenetia
DS201212-0081
2012
Davidheisser, B.Bort, A.M., Davidheisser, B., Meulemens, T., Davies, G.R.The origin and evolution of the lithospheric mantle beneath the Makondi fold belt in Botswana: an extensive geochemical study of peridotite xenoliths from the Lethlakane diamond mine.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, BotswanaDeposit - Lethlhakane
DS201212-0469
2012
Davidheriser, B.Meulemans, T.J., Borst, A.M., Davidheriser, B., Davies, G.R.The origin and modification of the sub-continental lithospheric mantle of Botswana: constraints from peridotite xenoliths of the Orapa mine.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, BotswanaDeposit - Orapa
DS201805-0973
2017
Davidsen, B.Ravna, E.K., Zozulya, D., Kullerud, K., Corfu, F., Nabelek, P.I., Janak, M., Slagstad, T., Davidsen, B., Selbekk, R.S., Schertl, H-P.Deep seated carbonatite intrusion and metasomatism in the UHP Tromso Nappe, northern Scandinavian Caledonides - a natural example of generation of carbonatite from carbonated eclogite.Journal of Petrology, Vol. 58, 12, pp. 2403-2428.Europe, Sweden, Norwaycarbonatite

Abstract: Carbonatites (sensu stricto) are igneous rocks typically associated with continental rifts, being emplaced at relatively shallow crustal levels or as extrusive rocks. Some carbonatites are, however, related to subduction and lithospheric collision zones, but so far no carbonatite has been reported from ultrahigh-pressure (UHP) metamorphic terranes. In this study, we present detailed petrological and geochemical data on carbonatites from the Tromsø Nappe—a UHP metamorphic terrane in the Scandinavian Caledonides. Massive to weakly foliated silicate-rich carbonate rocks, comprising the high-P mineral assemblage of Mg-Fe-calcite?±?Fe-dolomite?+?garnet?+?omphacitic clinopyroxene?+?phlogopite?+?apatite?+?rutile?+?ilmenite, are inferred to be carbonatites. They show apparent intrusive relationships to eclogite, garnet pyroxenite, garnet-mica gneiss, foliated calc-silicate marble and massive marble. Large grains of omphacitic pyroxene and megacrysts (up to 5?cm across) of Cr-diopside in the carbonatite contain rods of phlogopite oriented parallel to the c-axis, the density of rods being highest in the central part of the megacrysts. Garnet contains numerous inclusions of all the other phases of the carbonatite, and, in places, composite polyphase inclusions. Zircon, monazite and allanite are common accessory phases. Locally, veins of silicate-poor carbonatite (up to 10?cm across) occur. Extensive fenitization by K-rich fluids, with enrichment in phlogopite along contacts between carbonatite and silicate country rocks, is common. Primitive mantle-normalized incompatible element patterns for the carbonatite document a strong enrichment of light rare earth elements, Ba and Rb, and negative anomalies in Th, Nb, Ta, Zr and Hf. The carbon and oxygen isotope compositions of the carbonatite are distinctly different from those of the spatially associated calc-silicate marble, but also from mantle-derived carbonatites elsewhere. Neodymium and Sr isotope data coupled with the trace element distribution indicate a similarity of the Tromsø carbonatite to orogenic (off-craton) carbonatites rather than to anorogenic (on-craton) ones. U-Pb dating of relatively U-rich prismatic, oscillatory-zoned zircon gives an age of 454•5?±?1•1?Ma. We suggest that the primary carbonatite magma resulted from partial melting of a carbonated eclogite at UHP, in a deeply subducted continental slab.
DS2001-1156
2001
DavidsonThorkelson, D.J., Mortensen, Davidson, Creaser, PerezEarly Mesoproterozoic intrusive breccias in Yukon: the role of hydrothermal systems in reconstruction of NA.Precambrian Research, Vol. 111, No. 1-4, pp. 31-55.Canada, United States, Australia, YukonTectonics
DS2001-1157
2001
DavidsonThorkelson, FD.J., Mortensen, Creaser, Davidson, AbbottEarly Proterozoic magmatism in Yukon: constraints on the evolution of northwestern Laurentia.Canadian Journal of Earth Science, Vol. 38, No. 10, Oct. pp. 1479-94.YukonMagmatism - not specific to diamonds
DS2002-0803
2002
DavidsonKamenetsky, V.S., Davidson, Mernagh, Crawford, GemmellFluid bubbles in melt inclusions and pillow rim glasses: high temperature precursors to hydrothermal..Chemical Geology, Vol.183, 1-4, pp.349-64.MantleMelt - inclusions, Geochemistry
DS1975-0723
1978
Davidson, A.Davidson, A.The Blachford Lake Intrusive Suite: an Aphebian Alkaline Plutonic Complex in the Slave Province ,northwest Territories.Geological Survey of Canada (GSC), No. 78-1A, PP. 119-127.Canada, Northwest Territories, Thor LakeThor Lake, Rare Earth Elements (ree)
DS1989-0536
1989
Davidson, A.Green, A.G., Milkereit, B., Davidson, A., Percival, J.A., ParrishReflection seismic profiling of the Kapuskasing structural zone, SOURCE[ Geological Association of Canada (GAC) Annual Meeting Program AbstractsGeological Society of Canada (GSC