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SDLRC - Scientific Articles all years by Author - L-Lh


The Sheahan Diamond Literature Reference Compilation
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcementscalled the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Resource Center
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Media/Corporate References by Name for all years
A B C D-Diam Diamonds Diamr+ E F G H I J K L M N O P Q R S T U V W X Y Z
Tips for Users
Posted/Published Reference CodesThe SDLRC provides 3 types of references identified in the reference code. DS for scientific article, DM for a media article, and DC for a corporate announcement. Consider DS0512-0001. The DS stands for "diamond scientific". 05 stands for 2005, the year the reference was posted. 12 represents the month the reference was posted. For all years prior to 2015 the default month is 12. -0001 is the reference's identifier and it does not mean anything. The number below the refence code, ie 2015, is the year the article was published. Note that the posted year may sometimes be later than the published year.
Sort OrderReferences are sorted by the "author" name and when the reference was posted to the compilation.
Most RecentIf the reference code is highlighted yellow, the reference was made available through the most recent monthly compilation of new literature. Use this to check out new references. When new references are posted, we make it our priority to track down an online link and obtain an abstract. With regard to older references, tracking down an abstract and an online link is a work in progress.
Link to external location of article: If the title has a link, it means we have found a location online where you can either retrieve the full article free, or purchase access to it. The Sheahan Diamond Literature Service is not a technical article procurement service; if you want a restricted article, you must deal directly with the vendor who controls the copyright to the article.
Searching this page for a specific term or authorIn your Firefox browser click Edit in the menu bar and then Find. In the Find box that shows up at the bottom of the web page enter your search term. Firefox will highlight all occurrences. This is particularly helpful when the author you are seeking was not the lead author by whom the compilation is sorted.
Sending or sharing a referenceThe left column (Posted/Published) has an embedded hyperlink for each reference. In Firefox, if you right click on it, you can obtain the link url for that reference's location within the page, which you can copy and paste into an email or any other document. You can also use the "share this link" option to tweet, facebook etc the link.
Author Index
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years - L-Lh
Posted/
Published
AuthorTitleSourceRegionKeywords
DS201907-1555
2019
LKupenko, G.A., Vasilukov, D.M., McCammon, C., Charleton, S., Cerantola, V., Kantor, I., Chumakov, A.I.., Ruffer, R., Dubrovinsky, L, Sanchez-Valle, C.Magnetism in cold subducting slabs at mantle transition zone depths.Nature, Vol. 570, 7759, p. 102.Mantlesubduction

Abstract: The Earth’s crust-mantle boundary, the Mohorovicic discontinuity, has been traditionally considered to be the interface between the magnetic crust and the non-magnetic mantle1. However, this assumption has been questioned by geophysical observations2,3 and by the identification of magnetic remanence in mantle xenoliths4, which suggest mantle magnetic sources. Owing to their high critical temperatures, iron oxides are the only potential sources of magnetic anomalies at mantle depths5. Haematite (a-Fe2O3) is the dominant iron oxide in subducted lithologies at depths of 300 to 600 kilometres, delineated by the thermal decomposition of magnetite and the crystallization of a high-pressure magnetite phase deeper than about 600 kilometres6. The lack of data on the magnetic properties of haematite at relevant pressure-temperature conditions, however, hinders the identification of magnetic boundaries within the mantle and their contribution to observed magnetic anomalies. Here we apply synchrotron Mössbauer source spectroscopy in laser-heated diamond anvil cells to investigate the magnetic transitions and critical temperatures in Fe2O3 polymorphs7 at pressures and temperatures of up to 90 gigapascals and 1,300 kelvin, respectively. Our results show that haematite remains magnetic at the depth of the transition zone in the Earth’s mantle in cold or very cold subduction geotherms, forming a frame of deep magnetized rocks in the West Pacific region. The deep magnetic sources spatially correlate with preferred paths of the Earth’s virtual geomagnetic poles during reversals8 that might not reflect the geometry of the transitional field. Rather, the paths might be an artefact caused by magnetized haematite-bearing rocks in cold subducting slabs at mid-transition zone depths. Such deep sources should be taken into account when carrying out inversions of the Earth’s geomagnetic data9, and especially in studies of planetary bodies that no longer have a dynamo10, such as Mars.
DS1910-0068
1910
L.G.L.G.Alluvial Gold and Diamonds in the Earlier Days. #2South Africa Majority Special Issue., PP. 136-137.South AfricaHistory
DS201511-1838
2007
La Ferrara, E.Guidolin, M., La Ferrara, E.Diamonds are forever, war is not: is conflict bad for private firms?The American Economic Review, Vol. 97, 5, pp. 1978-1993.GlobalEconomics

Abstract: This paper studies the relationship between civil war and the value of firms in a poor, resource abundant country using microeconomic data for Angola. We focus on diamond mining firms and conduct an event study on the sudden end of the conflict, marked by the death of the rebel movement leader in 2002. We find that the stock market perceived this event as “bad news” rather than "good news" for companies holding concessions in Angola, as their abnormal returns declined by 4 percentage points. The event had no effect on a control portfolio of otherwise similar diamond mining companies. This finding is corroborated by other events and by the adoption of alternative methodologies. We interpret our findings in the light of conflict-generated entry barriers, government bargaining power and transparency in the licensing process.
DS1993-0870
1993
La Fleche, M.R.La Fleche, M.R., Schrijver, K., Tremblay, A.Geochemistry, origin and provenance of upper Proterozoic to upper Cambrian alkaline to transitional basaltic rocks in and contiguous to sector HumberzoneAmerican Journal of Science, Vol. 293, November pp. 980-1009AppalachiaGeochemistry, Humber Zone
DS1994-0972
1994
la Moigne, J.Lagabrielle, Y., la Moigne, J., Maury, R.C., Cotten, J.Volcanic record of the subduction of an active spreading ridge, Taitao Peninsula (southern Chile)Geology, Vol. 22, No. 6, June pp. 515-518ChileSubduction, Tectonics
DS200812-0282
2008
La Nuez, J.deDemeny, A., Casillas, R., Ahijado, A., La Nuez, J.de, Milton, J.A., Nagy, G.Carbonate xenoliths in La Palma: carbonatite or alteration product?Chemie der Erde, Vol. 68, 4, pp. 369-381.Europe, Canary IslandsGeochronology
DS2003-0767
2003
La Pierre, H.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played aChemical Geology, Vol. 201, 3-4, Nov. 14, pp. 55-89.British ColumbiaTectonics, Cache Creek, Slide Mountain Terrane, geochem
DS2003-0768
2003
La Pierre, H.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played aChemical Geology, Vol. 201, 1-2, pp. 55-89.British Columbia, Yukon, Alberta, Northwest TerritoriesMagmatism, tectonics
DS200412-1077
2003
La Pierre, H.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played a key role in continental crust growth.Chemical Geology, Vol. 201, 1-2, pp. 55-89.Canada, British Columbia, Yukon, Alberta, Northwest TerritoriesMagmatism, tectonics
DS200412-1078
2003
La Pierre, H.La Pierre, H., Bosch, D., Tardy, M., Struik, L.C.Late Paleozoic and Triassic plume derived magmas in the Canadian Cordillera played a key role in continental crust growth.Chemical Geology, Vol. 201, 3-4, Nov. 14, pp. 55-89.Canada, British ColumbiaTectonics, Cache Creek, Slide Mountain Terrane, geochem
DS1994-0114
1994
la Pointe, P.R.Barton, C.C., la Pointe, P.R.Fractals in the earth sciences #1Plenum Press, 261pGlobalBook -ad, Fractals
DS1995-0111
1995
la Pointe, P.R.Barton, C.C., la Pointe, P.R.Fractals in the earth sciences #2Plenum Press, GlobalBook -ad, Fractals
DS1999-0390
1999
La Prairie, L.F.La Prairie, L.F., Vuori, H.F., Dowsett, J.S.Darnley Bay: part 1. historical perspectives on exploration. part 2: theproject... mentions anomalies.8th. Calgary Mining forum, 5p. abstractNorthwest TerritoriesNews item, Darnley Bay
DS200812-0944
2008
La Prairie, L.L.Reford, S.W., La Prairie, L.L.Exploring for metals and diamonds at Darnley Bay. NT.Northwest Territories Geoscience Office, p. 51. abstractCanada, NunavutBrief overview - Darnley Bay
DS201112-0666
2011
La Terra, E.F.Menezes, P.T.L., La Terra, E.F.3D magnetic interpretation of the Regis kimberlite pipe, Minas Gerais, Brazil.Near Surface Geophysics, In press,South America, Brazil, Minas GeraisGeophysics - Regis
DS201312-0600
2011
La Terra, E.F.Menezes, P.T.L., La Terra, E.F.3 D magnetic interpretation of the Regis kimberlite pipe, Minas Gerais.Near Surface Geophysics, Vol. 9, 4, pp. 331-337.South America, BrazilDeposit - Regis
DS1994-0941
1994
Laaioki, K.Korobeynikov, A.N., Laaioki, K.Petrological aspects of the evolution of clinopyroxene composition in intrusive rocks Lovozero Alkali Massif.Geochemistry International, Vol. 31, No. 3, pp. 69-76.RussiaAlkaline rocks
DS1998-0790
1998
LaajokiKorobeinikov, A.N., Mitrofanov, Gehor, Laajoki, PavlovGeology and copper sulphide mineralization of the Salmagorskii ring igneouscomplex, Kola Peninsula.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2033-41.Russia, Kola PeninsulaAlkaline rocks, Salmagorsky Complex
DS1989-0840
1989
Laajoki, K.Laajoki, K.Stratigraphic classification and nomenclature of igneous and metamorphic rock bodies: discussion and replyGeological Society of America (GSA) Bulletin, Vol. 101, No. 5, May pp. 753-754GlobalClassification, Igneous/Metamorphic
DS1999-0719
1999
Laajoki, K.Strand, K., Laajoki, K.Application of the parasequence concept to the Paleoproterozoic record Of the northern FennoscandianPrecambrian Research, Vol. 97, No. 3-4, Sept. 1, pp. 253-68.Norway, FennoscandiaShield - history
DS2002-0441
2002
Laajoki, K.Evins, P.M., Mansfeld, J., Laajoki, K.Geology and geochronology of the Suomujarvi Complex: a new Archean gneiss region in the NE Baltic Shield, Finland.Precambrian Research, Vol. 116, No. 3-4, pp. 285-306.FinlandGeneral geology - not specific to diamonds
DS200612-0437
2005
Lab NotesGems &.Gemology, Lab NotesStrongly coloured natural type IIb blue diamonds.Gems & Gemology, Vol. 41, 3, Fall, p.258-9..TechnologyDiamond - colour
DS200612-0438
2005
Lab NotesGems &.Gemology, Lab NotesDiamond dyed rough.Gems & Gemology, Vol. 41, 3, Fall, p.257-258.TechnologyDiamond - colour
DS200812-0622
2007
Lab NotesLab NotesPhenakite as a rough diamond imitation.Gems & Gemology, Fall, p. 250.TechnologyPhenakite
DS200812-0623
2007
Lab NotesLab NotesNatural type IIb blue diamond with atypical electroluminescence.Gems & Gemology, Fall, pp. 246-48.TechnologyType IIa
DS201906-1309
2019
Lab notesLab notesThe largest diamond ever discovered in North America 552.7 ct. DiavikGems & Gemology, Vol. 55, 1, p. 91-2.Canada, Northwest Territoriesdeposit - Diavik

Abstract: In October 2018, a diamond weighing a remarkable 552.7 ct was recovered from the Diavik mine in Canada. This is by far the largest known gem diamond found to date in North America. It is nearly three times larger than the 187.63 ct Diavik Foxfire which was unearthed from the same mine in August 2015, and about twice the size of a 271 ct white diamond mined from the Victor mine in Canada. GIA’s New York laboratory had the opportunity to examine this notable diamond in late January 2019, before it went on public display at the Phillips Auctions in New York...(no abstract, full article)
DS201906-1310
2019
Lab notesLab notesCVD layer grown on natural diamondGems & Gemology, Vol. 55, 1, pp. 97-99.Globalsynthetic

Abstract: A 0.64 ct Fancy grayish greenish blue cushion modified brilliant (figure 1) was recently found to be a composite of synthetically grown and natural diamond. During testing, the infrared spectrum showed both strong absorption of nitrogen and the absorption of uncompensated boron, features characteristic of type Ia and type IIb diamonds, respectively (figure 2). The UV-Vis-NIR spectrum showed “cape” peaks, which are nitrogen-related defects, but also a sloping absorption into the red portion of the spectrum caused by uncompensated boron. It is very unusual for boron- and nitrogen-related defects to be seen together in natural diamonds, though an example has been seen before (Spring 2009 Lab Notes, pp. 55-57). Mixed-type diamonds always call for additional scrutiny...(no abstract, full article)
DS2001-0645
2001
Labbe, J-Y.Labbe, J-Y.Crustal lineaments and kimberlite discovery potential in western Nouveau-QuebecRessources Naturelle Quebec, PRO 2001-02, 7 p.Quebeccrustal lineaments, mineral potential maps, northeastern Superior craton
DS2001-0646
2001
Labbe, J-Y.Labbe, J-Y.Crustal lineaments and kimberlite discovery potential in western Nouveau Quebec.24EQuebec Department of Mines, No. PRO 2001-02, 7p.Quebec, UngavaStructure, tectonics, rifting, Lac Aigneau area
DS1994-0968
1994
Laberge, G.Laberge, G.Geology of the Lake Superior RegionGeoscience Press, 300pWisconsin, MichiganGreenstone belt, Keweenawan, Table of contents
DS1970-0949
1974
Laberge, G.L.Laberge, G.L.Major Structural Lineaments in the Precambrian of Central Wisconsin.First International Conference On Basement Tectonics., WisconsinMid-continent
DS1984-0442
1984
Laberge, G.L.Laberge, G.L., Myers, P.E.Two Early Proterozoic Successions in Central Wisconsin and Their Tectonic Significance.Geological Society of America (GSA) Bulletin., Vol. 95, No. 2, FEBRUARY PP. 246-253.United States, WisconsinMid Continent
DS1984-0636
1984
Laberge, G.L.Schulz, K.J., Laberge, G.L., Sims, P.K., Peterman, Z.E., Klasner.The Volcanic Plutonic Terrane of Northern Wisconsin: Implications for Early Proterozoic Tectonism, Lake Superior Region.Geological Association of Canada (GAC), Vol. 9, P. 103. (abstract.).MichiganMid-continent
DS1988-0394
1988
Laberge, G.L.Laberge, G.L.Exploration drill cores in the Wisconsin magmatic terraneUnited States Geological Survey (USGS) Open File, No. 88-0536, 72p. paper copy $ 11.25WisconsinBasement, Tectonics
DS1994-0969
1994
LaBerge, G.L.LaBerge, G.L.Geology of the Lake Superior regionPhoenix Press, 313p.Michigan, WisconsinGeneral geology -not specific to diamonds, Book -ad
DS201212-0112
2012
Labidi, J.Cartigny, P., Palot, M., Clog, M., Labidi, J., Thomassot, E., Aubaud, C., Busigny, V., Harris, J.W.On overview of the deep carbon cycle and its isotope heterogeneity.Goldschmidt Conference 2012, abstract 1p.MantleCarbon cycle
DS201606-1130
2016
Labidi, J.Zhang, Z., Dorfman, S.M., Labidi, J., Zhang, S., Li, M., Manga, M., Stixrude, L., McDonough, W.F., Williams, Q.Primordial metallic melt in the deep mantle.Geophysical Research Letters, Vol. 43, 8, pp. 3693-3697.MantleMelting

Abstract: Seismic tomography models reveal two large low shear velocity provinces (LLSVPs) that identify large-scale variations in temperature and composition in the deep mantle. Other characteristics include elevated density, elevated bulk sound speed, and sharp boundaries. We show that properties of LLSVPs can be explained by the presence of small quantities (0.3-3%) of suspended, dense Fe-Ni-S liquid. Trapping of metallic liquid is demonstrated to be likely during the crystallization of a dense basal magma ocean, and retention of such melts is consistent with currently available experimental constraints. Calculated seismic velocities and densities of lower mantle material containing low-abundance metallic liquids match the observed LLSVP properties. Small quantities of metallic liquids trapped at depth provide a natural explanation for primitive noble gas signatures in plume-related magmas. Our model hence provides a mechanism for generating large-scale chemical heterogeneities in Earth's early history and makes clear predictions for future tests of our hypothesis.
DS201607-1323
2016
Labidi, J.Zhang, Z., Dorfman, S.M., Labidi, J., Zhang, S., Li, M., Manga, M., Stixrude, L., McDonough, W.F., Williams, Q.Primordial metallic melt in the deep mantle.Geophysical Research Letters, Vol. 43, 8, pp. 3693-3699.MantleMelting

Abstract: Seismic tomography models reveal two large low shear velocity provinces (LLSVPs) that identify large-scale variations in temperature and composition in the deep mantle. Other characteristics include elevated density, elevated bulk sound speed, and sharp boundaries. We show that properties of LLSVPs can be explained by the presence of small quantities (0.3 -3%) of suspended, dense Fe-Ni-S liquid. Trapping of metallic liquid is demonstrated to be likely during the crystallization of a dense basal magma ocean, and retention of such melts is consistent with currently available experimental constraints. Calculated seismic velocities and densities of lower mantle material containing low-abundance metallic liquids match the observed LLSVP properties. Small quantities of metallic liquids trapped at depth provide a natural explanation for primitive noble gas signatures in plume-related magmas. Our model hence provides a mechanism for generating large-scale chemical heterogeneities in Earth's early history and makes clear predictions for future tests of our hypothesis.
DS202005-0744
2020
Labidi, J.Labidi, J., Barry, P.H., Bekaert, D.V., Broadley, M.W., Marty, B., Giunta, T., Warr, O., Sherwood Lollar, B., Fischer, T.P., Avice, G., Caracusi, A., Ballentine, C.J., Halldorsson, S.A., Stefansson, A., Kurz, M.D., Kohl, I.E., Young, E.D.Hydrothermal 15N15N abundances constrain the origins of mantle nitrogen.Nature, Vol. 580, 7803 pp. 367-371. Mantlenitrogen

Abstract: Nitrogen is the main constituent of the Earth’s atmosphere, but its provenance in the Earth’s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth’s accretion versus that subducted from the Earth’s surface is unclear1,2,3,4,5,6. Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare 15N15N isotopologue of N2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle d15N (the fractional difference in 15N/14N from air), N2/36Ar and N2/3He. Our results show that negative d15N values observed in gases, previously regarded as indicating a mantle origin for nitrogen7,8,9,10, in fact represent dominantly air-derived N2 that experienced 15N/14N fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the 15N15N data allow extrapolations that characterize mantle endmember d15N, N2/36Ar and N2/3He values. We show that the Eifel region has slightly increased d15N and N2/36Ar values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts11, consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has d15N values substantially greater than that of the convective mantle, resembling surface components12,13,14,15, its N2/36Ar and N2/3He ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume d15N values may both be dominantly primordial features.
DS1994-0970
1994
Labonne, B.Labonne, B.Small and medium scale mining... the Harare seminar and guidelinesNatural Resources forum, Vol. 18, No. 1, pp. 13-16ZimbabweMining -small scale
DS1994-0971
1994
Labonne, B.Labonne, B.Small and medium scale mining.. notes from the Harare seminar andguidelines.Natural Resources forum, Vol. 18, No. 1, February pp. 13-16.ZimbabweMining -small scale, Economics
DS200812-1000
2008
Laboucan, A.B.Sandeman, H.A., Barnett, R.L., Laboucan, A.B.An overview of the Mud Lake kimberlite, SW Slave Craton, Northwest Territories, and implications of the presence of high Cr2O3, CaO rich green garnets.9IKC.com, 3p. extended abstractCanada, Northwest TerritoriesDeposit - Mud Lake petrography
DS200712-0935
2007
Laboucan, B.Sandeman, H.A., Barnett, R.L., Laboucan, B., Flemming, R., Tubrett, M.Unique garnet compositions from the Mud Lake kimberlite SW Slave Province, NWT: an occurrence of rare high Cr-Ca green garnets.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, 1 pg. abstract p.70-71.Canada, Northwest TerritoriesGarnet analyses
DS1982-0356
1982
Labrecque, J.J.Labrecque, J.J., Nagata, K., Ishizaki, C., Ishizaki, K.Environmental Impact of Diamond Mining in the Guanamo Riverbasin.Agid Report No. 7, Hidden Wealth: Mineral Exploration Techni, PAPER F3, P. 185. (abstract.)GlobalChemistry, Waters
DS2001-0647
2001
Labroose, S.Labroose, S., Poirier, J.P., Lemouel, J.L.The age of the inner coreEarth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 111-123.MantleCore - boundary, Geochronology
DS200712-0591
2007
Labroose, S.Labroose, S., Jaupart, C.Thermal evolution of the Earth: secular changes and fluctuations of plate characteristics.Earth and Planetary Science Letters, Vol. 260, 3-4, pp. 465-481.MantleDynamics, tectonics, geothermometry
DS201012-0323
2010
LabrosseJavoy, M., Kaminski, E., Guyot,Andrault, Sanloup, Moreira, Labrosse, Jambon, Agrinier.Davaille, JaupartThe chemical composition of the Earth: enstatite chondrite models.Earth and Planetary Science Letters, Vol. 293, 3-4, pp. 259-268.MantleChemistry
DS2002-0909
2002
Labrosse, S.Labrosse, S.Hotspots, mantle plumes and core heat lossEarth and Planetary Science Letters, Vol.199,1-2,pp.147-56., Vol.199,1-2,pp.147-56.MantlePlumes
DS2002-0910
2002
Labrosse, S.Labrosse, S.Hotspots, mantle plumes and core heat lossEarth and Planetary Science Letters, Vol.199,1-2,pp.147-56., Vol.199,1-2,pp.147-56.MantlePlumes
DS200712-0384
2007
Labrosse, S.Grigne, C., Labrosse, S., Tackley, P.J.Convection under a lid of finite conductivity in wide aspect ratio models: effect of continents on the rate of mantle flow.Journal of Geophysical Research, Vol. 112, B8, B08403MantleConvection
DS200712-0385
2007
Labrosse, S.Grigne, C., Labrosse, S., Tackley, P.J.Convection under a lid of finite conductivity in wide aspect ratio models: heat flux scaling and application to continents.Journal of Geophysical Research, Vol. 112, B8, B08402MantleConvection
DS200712-0429
2007
Labrosse, S.Hernlund, J.W., Labrosse, S., Coltice, N.The energy balance at the core-mantle boundary.Plates, Plumes, and Paradigms, 1p. abstract p. A399.MantleGeothermometry
DS201312-0388
2013
Labrosse, S.Hirose, K., Labrosse, S., Hernlund, J.Composition and state of the core.Annual Review of Earth and Planetary Sciences, Vol. 41, pp. 657-691.MantleMineralogy
DS2003-1218
2003
Labrousse, L.Scharer, U., Labrousse, L.Dating the exhumation of UHP rocks and associated crustal melting in the NorwegianContributions to Mineralogy and Petrology, Vol. 144, 6, pp. 758-70.NorwayGeochronology, UHP
DS2003-1219
2003
Labrousse, L.Scharer, U., Labrousse, L.Dating the exhumation of UHP rocks and associated crustal melting in the NorwegianContributions to Mineralogy and Petrology, Vol. 144, 6, March pp. 758-77.NorwayUHP - ultra high pressure, Geochronology
DS200412-1741
2003
Labrousse, L.Scharer, U., Labrousse, L.Dating the exhumation of UHP rocks and associated crustal melting in the Norwegian Caledonides.Contributions to Mineralogy and Petrology, Vol. 144, 6, pp. 758-70.Europe, NorwayGeochronology, UHP
DS200512-0485
2005
Labrousse, L.Jolivet, L., Raimbourg, H., Labrousse, L., Avigad, D., Leroy, Y., Austrheim, H., Andersen, T.B.Softening triggered by eclogitization, the first step toward exhumation during continental subduction.Earth and Planetary Science Letters, Vol. 237, 3-4, Sept. 15, pp. 532-547.Europe, NorwayEclogite, subduction
DS2000-0717
2000
Labudia, H.C.Ntaflos, Th., Gunther, M., Labudia, H.C., Bjerg, E.A.Isotopic and geochemical evolution of the Cenozoic basalts from Rio Negro Patagonia Argentina.Igc 30th. Brasil, Aug. abstract only 4p.ArgentinaGeochronology, Basanites
DS1960-1149
1969
Labuz, A.L.Labuz, A.L.The Herkimer Diamond Grounds Former Schrader Property and Related Properties.Rocks And Minerals, Vol. 44, PP. 243-250.United States, Appalachia, New YorkHerkimer Diamonds
DS201412-0778
2014
Lacalamita, M.Schingaro, E., Kullerud, K., Lacalamita, M., Mesto, E., Scordari, F., Zozulya, D., Erambert, M., Ravna, E.J.K.Yangzhumgite and phlogopite from the Kvaloya lamproite ( North Norway): structure, composition and origin.Lithos, Vol. 210-211, pp. 1-13.Europe, NorwayLamproite
DS201212-0392
2012
Lacamita, M.Lacamita, M., Mesto, E., Scordari, F., Schingaro, E.Chemical and structural study of 1M and 2M1 phlogopites coexisting in the same Kaseny kamafugitic rock ( SW Uganda).Physics and Chemistry of Minerals, Vol. 39, 8, pp. 601-611.Africa, UgandaKamafugite
DS1991-0947
1991
Lacazette, A.Lacazette, A.A new stereo graphic technique for the reduction of scanline survey dat a of geologic fracturesComputers and Geosciences, Vol. 17, No. 3, pp. 445-464GlobalStereographic technique
DS1900-0147
1903
Lace Diamond CompanyLace Diamond CompanyThe Lace Diamond Mine Company ReportSouth Africa Mines Commerce and Industry, Vol. 1, MAY 23RD. PP. 238-239.Africa, South AfricaCompany Report
DS2001-1295
2001
Lacelle, D.Zdanowicz, C., Fisher, D., Clark, I., Lacelle, D.Ice marginal studies on Barnes Ice Cap, Baffin Island: clues to the history of the Laurentide ice sheet.29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p. 97.Northwest Territories, Baffin IslandGeomorphology
DS1990-0898
1990
Lachenbruch, A.H.Lachenbruch, A.H., Morgan, P.Continental extension, magmatism and elevation; formal extensions and rules of thumbTectonophysics, special issue on heat and detachment in continental, Vol. 174, No. 1-2, pp. 39-62GlobalCrustal extension, Magmatism
DS201707-1360
2017
Lachhman, D.Reis, N.J., Nadeau, S., Fraga, L.M., Menezes Betiollo, L., Telma Lins Faraco, M., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil Guyana border in the Guiana shield, northern Amazonian craton - results of the Brazil Guyana geology and geodiversity mapping project.Brazil Journal of Geology, Vol. 47, 1, pp. 43-57.South America, Brazil, Guyanacraton

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil-Guyana border zone allowed reviewing and in- tegrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú-Ireng River between Mount Roraima (the tri- ple-border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro-Burro Group of Guyana.
DS201810-2371
2018
Lachhman, D.Reis, N.J., Nadeau, S., Fraga, L.M., Betiollo, L.M., Faraco, M.T.L., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, northern Amazonian craton- results of the Brazil-Guyana geology and geodiversity mapping project.Brazilian Journal of Geology, Vol. 47, 1, pp. 43-57.South America, Brazil, Guyanacraton

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil-Guyana border zone allowed reviewing and in- tegrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú-Ireng River between Mount Roraima (the tri- ple-border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro-Burro Group of Guyana.
DS201904-0772
2017
Lachhman, D.Reis, N.J., Nadeau, S., Fraga, L.M., Menezes Betiollo, L., Telma Lins, Faraco, M., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, northern Amazonian craton - results of the Brazil Guyana geology and geodiversity mapping project.Brazilian Journal of Geology, Vol. 41, 1, pp. 43-57.South America, Brazil, GuyanaGuiana shield

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil-Guyana border zone allowed reviewing and integrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú-Ireng River between Mount Roraima (the triple-border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro-Burro Group of Guyana.
DS200612-1460
2005
Lackey, J.S.Valley, J.W., Lackey, J.S., Cavosie, A.J., Clechenko, C.C., Spicuzza, M.J., Basei, M.A.S., Bindeman, I.N.4.4 billion years of crustal maturation: oxygen isotope ratios.Contributions to Mineralogy and Petrology, Vol. 150, 8, Dec. pp. 561-580.MantleGeochronology
DS200812-0372
2008
Lackey, J.S.Fu, B., Page, F.Z., Cavosie, A.J., Fournelle, J., Kita, N.T., Lackey, J.S., Wilde, S.A., Valley, J.W.Ti in zircon thermometry: applications and limitations.Contributions to Mineralogy and Petrology, 37p. in press availableTechnologyGeothermometry - kimberlites
DS201611-2132
2016
Lackey, J.S.Poletti, J.E., Cottle, J.M., Hagen-Peter, G.A., Lackey, J.S.Petrochronological constraints on the origin of the Mountain Pass ultrapotassic and carbonatite intrusive suite, California.Journal of Petrology, In press available, 44p.United States, CaliforniaCarbonatite

Abstract: Rare earth element (REE) ore-bearing carbonatite dikes and a stock at Mountain Pass, California, are spatially associated with a suite of ultrapotassic plutonic rocks, and it has been proposed that the two are genetically related. This hypothesis is problematic, given that existing geochronological constraints indicate that the carbonatite is ~15-25 Myr younger than the ultrapotassic rocks, requiring alternative models for the formation of the REE ore-bearing carbonatite during a separate event and/or via a different mechanism. New laser ablation split-stream inductively coupled plasma mass spectrometry (LASS-ICP-MS) petrochronological data from ultrapotassic intrusive rocks from Mountain Pass yield titanite and zircon U-Pb dates from 1429?±?10 to 1385?±?18?Ma, expanding the age range of the ultrapotassic rocks in the complex by ~20 Myr. The ages of the youngest ultrapotassic rocks overlap monazite Th-Pb ages from a carbonatite dike and the main carbonatite ore body (1396?±?16 and 1371?±?10?Ma, respectively). The Hf isotope compositions of zircon in the ultrapotassic rocks are uniform, both within and between samples, with a weighted mean eHfi of 1•9?±?0•2 (MSWD?=?0•9), indicating derivation from a common, isotopically homogeneous source. In contrast, in situ Nd isotopic data for titanite in the ultrapotassic rocks are variable (eNdi?=?-3•5 to -12), suggesting variable contamination by an isotopically enriched source. The most primitive eNdi isotopic signatures, however, do overlap eNdi from monazite (eNdi?=?-2•8?±?0•2) and bastnäsite (eNdi?=?-3•2?±?0•3) in the ore-bearing carbonatite, suggesting derivation from a common source. The data presented here indicate that ultrapotassic magmatism occurred in up to three phases at Mountain Pass (~1425, ~1405, and ~1380?Ma). The latter two stages were coeval with carbonatite magmatism, revealing previously unrecognized synchronicity in ultrapotassic and carbonatite magmatism at Mountain Pass. Despite this temporal overlap, major and trace element geochemical data are inconsistent with derivation of the carbonatite and ultrapotassic rocks by liquid immiscibility or fractional crystallization from common parental magma. Instead, we propose that the carbonatite was generated as a primary melt from the same source as the ultrapotassic rocks, and that although it is unique, the Mountain Pass ultrapotassic and carbonatite suite is broadly similar to other alkaline silicate-carbonatite occurrences in which the two rock types were generated as separate mantle melts.
DS2001-0648
2001
Lackie, M.Lackie, M., Clark, D.A key paleomagnetic pole for the Early Permian for Australia and GondwanaGemoc Annual Report 2000, p. 31.Australia, GondwanaGeophysics - Paleomagnetism
DS201502-0096
2014
laclamita, M.Schingaro, E., Kullerud, K., laclamita, M., Mesto, E., Scordari, F., Zozulya, D., Erambert, M., Ravna, E.J.K.Yangzhumingite and phlogopite from the Kvaloya lamproite (North Norway): structure, composition and origin.Lithos, Vol. 210-211, pp. 1-13.Europe, NorwayLamproite
DS2002-0911
2002
Lacombe, O.Lacombe, O., Mouthereau, F.Basement involved shortening and deep detachment tectonics in forelands of orogens insights from recent collision belts. (Taiwan, Western Alps, Pyrenees)Tectonics, Vol. 21, No. 6, 10.1029/2001TC001018EuropeTectonics - not specific to diamonds
DS201510-1811
2015
Lacrampe, J.Vandenberg, J.A., Herrell, M., Faithful, J.W., Snow, A.M., Lacrampe, J., Bieber, C., Dayyani, S., Chisholm, V.Multiple modeling approach for the aquatic effects assessment of a proposed northern diamond mine development. Gahcho KueMine Water and the Environment, in press available, 19p.Canada, Northwest TerritoriesDeposit - Gahcho Kue

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

Abstract: Eight water models were used to assess potential aquatic environmental effects of the proposed Gahcho Kué diamond mine on groundwater and surface water flow and quality in the Northwest Territories, Canada. This sequence of models was required to cover different spatial and temporal domains, as well as specific physico-chemical processes that could not be simulated by a single model. Where their domains overlapped, the models were interlinked. Feedback mechanisms amongst models were addressed through iterative simulations of linked models. The models were used to test and refine mitigation plans, and in the development of aquatic component monitoring programs. Key findings generated by each model are presented here as testable hypotheses that can be evaluated after the mine is operational. This paper therefore offers a record of assumptions and predictions that can be used as a basis for post-validation.
DS201501-0031
2014
Lacrampe-Couloume, G.Lollar, B.S., Onstott, T.C., Lacrampe-Couloume, G., Ballentine, C.J.The contribution of the Precambrian continental lithosphere to global H2 production.Nature, Vol. 516, Dec. 18, pp. 379-382.MantleHydrogeology
DS1860-0946
1896
Lacroix, A.Lacroix, A.Diamant, 1896Mineralogie de la France et des Colonies, pp. 354-6.Africa, AlgeriaDiamond Synthesis
DS1860-1037
1898
Lacroix, M.A.Lacroix, M.A.Note sur Les Mineraux et Les Roches du Gisement Diamantifere de Monastery (etat Libre D'orange) et sur Ceux du Griqualand.Soc. Min. France (paris) Bulletin., Vol. 21, PP. 22-29. ALSO: Neues Jahrbuch fnr Mineralogie, P. 12. BD. 1, (Africa, South Africa, Orange Free StateMineralogy
DS2001-0649
2001
Lacroix, S.Lacroix, S., Doucet, P., Jean, A.Diamond and nickel potential of northern Quebec attracts attentionProspectors and Developers Association of Canada (PDAC) Exploration and development Highlights, pp. 10-11.Quebec, Ungava, LabradorKimberlites, Exploration - discoveries
DS2002-0912
2002
Lacroix, S.Lacroix, S.Diamond discoveries in the far north bolster exploration spendingProspectors and Developers Association of Canada (PDAC) Exploration and Development Highlights, pp. 10-11.QuebecNews item - brief review
DS2003-0769
2003
Lacroix, S.Lacroix, S.Diamond discoveries launch biggest-ever map staking rushExploration and Development Highlights, March 2003, p. 12-14QuebecNews item, Ashton, Renard, James Bay area - Majescor, Canabrava, BHPBilliton
DS200412-1079
2004
Lacroix, S.Lacroix, S.Cape Smith and Otish have them exploring la belle province.PDAC Exploration and Developments Highlights, pp. 10-12.Canada, Quebec, Otish MountainsBrief overview - diamond mentioned
DS1860-1093
1899
Lacy, G.Lacy, G.Pictures of Travel, Sport and AdventureLondon: C.A. Pearson, 420P.Africa, South AfricaTravelogue
DS1998-0823
1998
Lacy, W.Lacy, W.Introduction to geology and hard rock miningMountain Mineral Law Foundation, $ 25.00GlobalBook - ad, Geology for non-geologists
DS1992-0973
1992
Ladeira, E.A.Machado, N., Noce, C.M., Ladeira, E.A., Belo de Oliveira, O.uranium-lead (U-Pb) (U-Pb) geochronology of Archean magmatism and Proterozoic metamorphism in the Quadrilatero Ferrifero, southern Sao Francisco craton, BrasilGeological Society of America (GSA) Bulletin, Vol. 104, No. 9, September pp. 1221-1227BrazilGeochronology, Proterozoic
DS201604-0617
2016
Ladenburger, S.Ladenburger, S., Marks, M.A.W., Upton, B., Hill, P., Wenzel, T., Markl, G.Compositional variation of apatite from rift related alkaline igneous rocks of the Gardar Province, South Greenland.American Mineralogist, Vol. 101, pp. 612-626.Europe, GreenlandAlkalic

Abstract: Textural and compositional variations of apatite from four intrusions with different characteristic features of the rift-related alkaline Gardar Province were investigated: dyke rocks that belong to the most primitive rocks of the Province (Isortoq), nepheline-syenites associated with a carbonatite (Grønnedal-Ika), SiO2-saturated and SiO2-oversaturated syenites (Puklen) and nepheline-syenites displaying the transition from miaskitic to agpaitic mineral assemblages (Motzfeldt, Fig.1). Additionally, apatites from these intrusions were compared with other apatites of the Gardar Province. These include apatites from the Older Giant Dyke Complex, the Younger Giant Dyke Complex (both from the Tugtutôq region) and a narsarsukite-bearing trachytic dyke (Igdlutalik), as well as apatites from the Kûngnât, the North Qôroq and the Ilímaussaq intrusive complexes. This results in a complete overview of rift-related magmatites of the Gardar Province, ranging from primitive to highly evolved rocks. Backscattered electron images reveal the presence of various types of apatite textures including (i) growth zonation (concentric and oscillatory) that formed during magmatic differentiation and (ii) overgrowth and secondary textures (rounded cores, patchy zonation and overgrowth rims) due to fluid/melt induced metasomatic overprint and intracrystalline diffusion (Fig.2). Additionally, apatite compositions were analyzed with wavelength-dispersive electron microprobe analyses. During the crystallization history of the different intrusions, as well as within samples (documented by zoning patterns), increasing concentrations are observed for Si, REE, Na and F, whereas Cl shows a decreasing trend. However, for F, Cl and Na these trends are only observed in dyke rocks. Compositional variation of the investigated apatites is mainly due to substitution of Ca and P by variable amounts of Si, Na and REE. This study reveals that variations in the chemical composition of apatite are useful tools to obtain geochemical information about the host magma and its magmatic evolution. Here, Si and REE were found to be reliable petrogenetic indicators, whereas Na, F and Cl are only applicable in fast cooling systems to avoid redistribution of those elements.
DS1985-0377
1985
Laderoue, D.G.Laderoue, D.G., Evans, N.J., Mitchell, R.H.Lamprophyres Associated with the Coldwell Alkaline Complex, n.w. Ontario.Geological Association of Canada (GAC)., Vol. 10, P. A 33, (abstract.).Canada, OntarioMineralogy
DS1991-1175
1991
Laderoute, D.G.Mitchell, R.H., Platt, R.G., Downey, M., Laderoute, D.G.Petrology of alkaline lamprophyres from the Coldwell alkaline complex, northwestern OntarioCanadian Journal of Earth Sciences, Vol. 28, No. 10, October pp. 1653-1663OntarioAlkaline lamprophyres, Petrology, Coldwell
DS2001-0307
2001
Ladygina, M.Y.Evdokimov, M.D., Ladygina, M.Y., Nesterov, A.R.Morphology of diamonds as a possible indicator of their genesisNeues Jahrbuch fnr Mineralogie Abh., Vol. 176, No. 2, pp. 153-177.GlobalDiamond - morphology, Diamond - genesis
DS2001-0308
2001
Ladygina, M.Y.Evdorkimov, M.D., Ladygina, M.Y., Nesterov, A.R.Morphology of diamonds as possible indicator of their genesisNeues Jahrbuch Mineralogische Abhandlung, Vol. 176, No. 3, pp. 153-77.RussiaDiamond - morphology, Genesis
DS1998-0824
1998
LaFehr, T.R.LaFehr, T.R.On Talwani's errors in the total Bouguer reductionGeophysics, Vol. 63, No. 4, July-Aug. pp. 1125-36GlobalGeophysics - bouguer
DS201703-0424
2017
LaFlamme, C.LaFlamme, C., McFarlane, C.R.M., Fisher, C.M., Kirkland, C.L.Multi-mineral geochronology: insights into crustal behaviour during exhumation of an orogenic root.Contributions to Mineralogy and Petrology, in press available, 18p.CanadaCraton, Rae, Hearne
DS1989-1037
1989
Laflamme, J.H.G.Mitchell, R.H., Laflamme, J.H.G., Cabri, L.J.Rhenium sulphide from the Coldwell Complex,northwestern Ontario, CanadaMineralogical Magazine, Vol. 53, No. 373, Pt. 5, December pp. 635-636OntarioCarbonatite, Coldwell Complex -sulphid
DS2000-0198
2000
LafonDallagnol, 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
DS200612-0302
2006
Lafon, J.M.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
DS201112-0756
2011
Lafon, J.M.Oliveira, E.P., Souza, Z.S., McNaughton, N.J., Lafon, J.M., Costa, F.G., Figueiro, A.M.The Rio Capim volcanic plutonic sedimentary belt, Sao Francisco craton, Brazil: geological, geochemical and isotopic evidence for oceanic accretion during....Gondwana Research, Vol. 19, 3, pp. 735-750.South America, BrazilPaleoproterozoic continental collision
DS201809-2055
2018
Lafon, J.M.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
DS1994-0367
1994
Lafon, J-M.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
DS200912-0772
2009
Lafon, J-M.Travassos da Rosa Costa, L., Monie, P., Lafon, J-M., Arnaud, N.C.40 Ar 39 Ar geochronology across Archean and Paleoproterozoic terranes from southeastern Guiana Shield: evidence for contrasting cooling histories.Journal of South American Earth Sciences, Vol. 27, 2-3, pp. 113-128.South America, BrazilGeochronology
DS201812-2833
2016
Lafon, J-M.Kroonenberg, S.B., de Roever, E.W.F., Fraga, L.M., Faraco, T., Lafon, J-M., Cordani, U., Wong, T.E.Paleoproterzoic evolution of the Guiana Shield in Suriname: a revised model.Netherlands Journal of Geolsciences, Vol. 95, 4, pp. 491-522.South America, SurinameGuiana shield

Abstract: The Proterozoic basement of Suriname consists of a greenstone-tonalite-trondhjemite-granodiorite belt in the northeast of the country, two high-grade belts in the northwest and southwest, respectively, and a large granitoid-felsic volcanic terrain in the central part of the country, punctuated by numerous gabbroic intrusions. The basement is overlain by the subhorizontal Proterozoic Roraima sandstone formation and transected by two Proterozoic and one Jurassic dolerite dyke swarms. Late Proterozoic mylonitisation affected large parts of the basement. Almost 50 new U-Pb and Pb-Pb zircon ages and geochemical data have been obtained in Suriname, and much new data are also available from the neighbouring countries. This has led to a considerable revision of the geological evolution of the basement. The main orogenic event is the Trans-Amazonian Orogeny, resulting from southwards subduction and later collision between the Guiana Shield and the West African Craton. The first phase, between 2.18 and 2.09 Ga, shows ocean floor magmatism, volcanic arc development, sedimentation, metamorphism, anatexis and plutonism in the Marowijne Greenstone Belt and the adjacent older granites and gneisses. The second phase encompasses the evolution of the Bakhuis Granulite Belt and Coeroeni Gneiss Belt through rift-type basin formation, volcanism, sedimentation and, between 2.07 and 2.05 Ga, high-grade metamorphism. The third phase, between 1.99 and 1.95 Ga, is characterised by renewed high-grade metamorphism in the Bakhuis and Coeroeni belts along an anticlockwise cooling path, and ignimbritic volcanism and extensive and varied intrusive magmatism in the western half of the country. An alternative scenario is also discussed, implying an origin of the Coeroeni Gneiss Belt as an active continental margin, recording northwards subduction and finally collision between a magmatic arc in the south and an older northern continent. The Grenvillian collision between Laurentia and Amazonia around 1.2-1.0 Ga caused widespread mylonitisation and mica age resetting in the basement.
DS202012-2236
2020
Lafon, J-M.Neto, J.M.M., Lafon, J-M.Crustal growth and reworking of Archean crust within the Rhyacian domains of the southeastern Guiana Shield, Brazi: evidence from zircon U-Pb-Hf and whole rock Sm-Nd geochronology.Journal of South American Earth Sciences, Vol. 103, 102740 29p pdfSouth America, Brazilcraton

Abstract: The southeastern Guiana Shield, northern Amazonian Craton, is part of a Paleoproterozoic orogenic belt that was built up during the Transamazonian orogenic cycle (2.26-1.95 Ga). This cycle includes large segments of Rhyacian juvenile crust and some reworked Archean terranes. The geology in this region consists mainly of Paleoproterozoic granulitic-migmatitic-gneissic complexes, deformed and metamorphosed metavolcanic and metasedimentary rocks, and granitoids (granitic and TTG magmatism). Three tectonic domains are distinguished in the Brazilian territory of the southeastern Guiana Shield. They are known as the Amapá Block, Lourenço Domain, and Carecuru Domain. The Amapá Block is a Meso-Neoarchean continental block that was intensely reworked during the Transamazonian orogeny. The other two domains represent Rhyacian landmasses, the evolution of which involved several stages of subduction of oceanic lithosphere in magmatic arc environments. There are also relics of reworked Archean continental crust, the formation of which was followed by a collisional stage of tectonic accretion of the magmatic arcs. Whole-rock Sm-Nd and U-Pb zircon geochronology have confirmed the juvenile character of much of this Transamazonian orogenic belt. However, for the Lourenço and Carecuru domains, Nd isotopic signatures indicate the participation of Meso-Neoarchean crustal material in the sources of the magmatic rocks. Combined zircon U-Pb and Lu-Hf isotopic analyses by LA-ICP-MS were performed on eleven Rhyacian granitoids and orthogneisses from the Lourenço and Carecuru domains. The aim was to verify the extension of the influence of the Archean continental crust in the adjacent Paleoproterozoic domains. The main magmatic episodes were identified in the Lourenço Domain (~2.17-2.18, 2.14 and 2.12-2.09 Ga) and Carecuru Domain (2.14 Ga) by U-Pb zircon geochronology. The Lu-Hf isotope data point to the predominance of crustal reworking processes (?Hf(2.2-2.1 Ga) < 0; 67% of zircon crystals) during the formation of Lourenço and Carecuru domains. Hf model ages were found to be mostly Archean (98.4%), even for zircon grains that have positive ?Hf(2.2-2.1 Ga) values. For the terrane at the border of the Lourenço and Carecuru domains with the Amapá Block, assimilation of Archean crust of different ages and proportions in a magmatic arc environment accounts for the Hf-Nd isotopic signatures and Hf model ages of Rhyacian magmatism. In the northwestern part of the Lourenço Domain, more than 100 km north of the Amapá Block, the Hf-Nd isotopic signatures and Hf model ages indicate the participation of Archean crustal material, either as continental fragments and/or through incorporation of continental sediments in island arc environments, similar to what has been recorded for some Birimian terranes of the West African Craton in Ghana.
DS1975-0068
1975
Lafountain, L.J.Dobecki, T.L., Lafountain, L.J.Seismicity and Structure Along a Portion of the Midcontinent Geophysical Anomaly.Eos, Vol. 56, No. 9, PP. 602-603. (abstract.).KansasMid-continent
DS201812-2836
2018
Lafranchi, R.A.Lafranchi, R.A.A view of the potential of diamondiferous mineralization in Bahia using multi-source data.7th Symposio Brasileiro de Geologia do Diamante , Title only South America, Brazil, Bahiatechnology
DS1994-0972
1994
Lagabrielle, Y.Lagabrielle, Y., la Moigne, J., Maury, R.C., Cotten, J.Volcanic record of the subduction of an active spreading ridge, Taitao Peninsula (southern Chile)Geology, Vol. 22, No. 6, June pp. 515-518ChileSubduction, Tectonics
DS1996-0159
1996
Lagabrielle, Y.Bourgopis, J., Martin, H., Lagabrielle, Y., et al.Subduction erosion related to spreading ridge subduction: Titao peninsula(Chile triple junction)Geology, Vol. 24, No. 8, August pp. 723-726ChileSubduction, Tectonics
DS201012-0190
2010
Lagabrielle, Y.Faccenna, C., Becker, T.W., Lallemand, S., Lagabrielle, Y., Funiciello, F., Piromallo, C.Subduction triggered magmatic pulses: a new class of plumes?Earth and Planetary Science Letters, Vol. 299, 1-2, Oct. 15, pp. 54-68.MantleMagmatism
DS1992-0041
1992
Lager, G.A.Armbruster, T., Geiger, C.A., Lager, G.A.Single-crystal x-ray structure study of synthetic pyrope almandine garnet sat 100 and 293 kAmerican Mineralogist, Vol. 77, No. 5, 6, May-June pp. 512-521GlobalGarnet mineralogy, Synthetic pyrope
DS1996-1120
1996
LagnyPinna, P., Cocherie, A., Thieblemont, Feybesse, LagnyEvolution geodynamique du craton est-Africain et determinisme gitologueChron. Recherche Miniere, No, 525, pp. 33-43Tanzania, Kenya, UgandaTectonics, Metallogeny
DS201112-0534
2011
Lagos, M.Konig, S., Munker, C., Hohl, S., Paulick, H., Barth, A.R., Lagos, M., Pfander, J., Buchl, A.The Earth's tungsten budget during mantle melting and crust formation.Geochimica et Cosmochimica Acta, Vol. 78, 8, pp. 2119-2136.MantleMelting - not specific to diamonds
DS201312-0053
2013
Lagos, M.Ballhaus, C., Laurenz, V., Munker, C., Fonseca, R.O.C., Albarede, F., Rohrbach, A., Lagos, M., Schmidt, M.W., Jochum, K-P., Stoll, B., Weis, U., Helmy, H.M.The U /Pb ratio of the Earth's mantle - a signature of late volatile addition.Earth and Planetary Interiors, Vol. 362, pp. 237-245.MantleMelting
DS1920-0187
1924
Lagrange, E.Lagrange, E.Les Mines Diamantiferes de Kimberley, Les Degagements Gazeux et la Pression Atmospherique.Ciel Et Terre., Vol. 40, NOVEMBER and DECEMBER PP. 307-308.South Africa, Kimberley AreaMining Engineering
DS2003-0134
2003
Lagroix, F.Borradaile, G.J., Werner, T., Lagroix, F.Differences in paleomagnetic interpretations due to the choice of statisticalTectonophysics, Vol. 363, 1-2, Feb. 20, pp. 103-26.OntarioGeophysics - magnetics
DS2003-0135
2003
Lagroix, F.Borradaile, G.J., Werner, T., Lagroix, F.Difference in paleomagnetic interpretations due to choice of statistical, demagnetizationTectonophysics, Vol. 363, No. 1-2, Feb. 20, pp. 103-125.OntarioPaleomagnetics, tectonics
DS200412-0184
2003
Lagroix, F.Borradaile, G.J., Werner, T., Lagroix, F.Differences in paleomagnetic interpretations due to the choice of statistical, demagnetization and correction techniques: KapuskTectonophysics, Vol. 363, 1-2, Feb. 20, pp. 103-26.Canada, OntarioGeophysics - magnetics
DS1992-1754
1992
Laguta, O.N.Zolotukhin, V.V., Laguta, O.N., Malyuk, B.I.Genesis of komatiites of different continents, as inferred from dat a on their chemical compositionDoklady Academy of Science USSR, Earth Science Section, Vol. 312, No. 3, pp. 177-180RussiaKomatiites, Geochemistry
DS1992-1755
1992
Laguta, O.N.Zolotukhin, V.V., Malyuk, B.I., Laguta, O.N.Genetic aspects of deep seated petrogenesis of komatiite magmasSoviet Geology and Geophysics, Vol. 33, No. 1, pp. 29-39Russia, Commonwealth of Independent States (CIS)Komatiite, Petrology
DS1992-1756
1992
Laguta, O.N.Zolotukin, V.V., Malyuk, B.I., Laguta, O.N.Komatiites and the problem of basalt genesisRussian Geology and Geophysics, Vol. 33, No. 3, pp. 48-56Russia, Commonwealth of Independent States (CIS)Komatiites, Genesis -basalt
DS1998-1523
1998
Laguta, O.N.Vasilev, Y.R., Zolotukhin, V.V., Laguta, O.N.Shoshonites of the Northern Siberian PlatformDoklady Academy of Sciences, Vol. 361A, No. 6, pp. 799-03.Russia, SiberiaMagmatism, Shoshonites
DS1995-1044
1995
Lahaye, Y.Lahaye, Y., Arndt, N., Gruau, G.The influence of alteration on the trace element and neodymium isotopic compositions of komatiitesChemical Geology, Vol. 126, No. 1, Nov. 20, pp. 43-64AustraliaKomatiites, Alteration, Metasomatism
DS2003-0549
2003
Lahaye, Y.Hanrahan, M., Stachel. T., Brey, G.P., Lahaye, Y.Garnet peridotite xenoliths from the Koffiefontein mine, South Africa8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractSouth AfricaDeposit - Koffiefontein
DS2003-0770
2003
Lahaye, Y.Lahaye, Y., Brey, G.P.Scale and timing constraints on chemical redistribution between minerals of a composite8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractSouth AfricaMantle geochemistry, Deposit - Kimberley
DS200412-0784
2003
Lahaye, Y.Hanrahan, M., Stachel,T., Brey, G.P., Lahaye, Y.Garnet peridotite xenoliths from the Koffiefontein mine, South Africa.8 IKC Program, Session 6, POSTER abstractAfrica, South AfricaMantle petrology Deposit - Koffiefontein
DS200512-0960
2004
Lahaye, Y.Seitz, H-M., Brey, G.P., Lahaye, Y., Durali, S., Weyer, S.Lithium isotopic signatures of peridotite xenoliths and isotopic fractionation at high temperature between olivine and pyroxenes.Chemical Geology, Vol. 212, 1-2, pp. 163-177.MantlePetrology - not specific to diamonds
DS200612-0464
2006
Lahaye, Y.Girnis, A.V., Bulatov, V.K., Lahaye, Y., Brey, G.P.Partitioning of trace elements between carbonate silicate melts and mantle minerals: experiment and petrological consequences.Petrology, Vol. 14, 5, pp. 492-514.MantleMelts
DS200612-0708
2006
Lahaye, Y.Klama, K., Lahaye, Y., Weyer, S., Brey, G.P.Episodic versus long tern recycling processes within the Archean South African crust.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 21. abstract only.Africa, South AfricaSubduction
DS200612-0776
2006
Lahaye, Y.Lazarov, M., Brey, G., Lahaye, Y.Mapping of the Kaapvaal craton lithosphere with garnets from a polymict peridotite.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 345. abstract only.Africa, South AfricaGeochemistry - garnets
DS200812-0141
2008
Lahaye, Y.Brey, G.P., Bulatov, V.K., Girnis, A.V., Lahaye, Y.Experimental melting of carbonated peridotite at 6-10 GPa.Journal of Petrology, Vol. 49, 4, pp. 797-821.MantleMelting
DS200812-0624
2008
Lahaye, Y.Lahaye, Y., Kogarko, L.N., Brey, G.P.Isotopic (Nd, Hf, Sr) composition of super large rare metal deposits from the Kola Peninsula using in-situ LA MC ICPMS9IKC.com, 3p. extended abstractRussia, Kola PeninsulaDeposit - Khibina, Lovosero
DS200912-0393
2009
Lahaye, Y.Kogarko,N.,Lahaye, Y., Brey, G.P.Plume related mantle source of super large rare metal deposits from the Lovozero and Khibin a massifs on the Kola Peninsula, east Baltic Shield: Sr, Nd, Hf isotope ssytematics.Mineralogy and Petrology, in press availableEurope, Baltic Shield, Kola PeninsulaAlkalic
DS201112-0895
2011
Lahaye, Y.Saalmann, K., Gerdes, A., Lahaye, Y., Hartmann, L.A., Remus, M.V.D., Laufer, A.Multiple accretion at the eastern margin of the Rio de la Plat a craton: the prolonged Brasiliano orogeny in southernmost Brazil.International Journal of Earth Sciences, Vol. 100, 2, pp. 355-378.South America, BrazilCraton, not specific to diamonds
DS202008-1405
2020
Lahaye, Y.Kara, J., Vaisanen, M., Heinonen, J.S., Lahaye, Y., O'Brien, H., Huhma, H.Tracing arcologites in the Paleoproteroic era - a shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian shield.Lithos, in press available, 68p. PdfEurope, Fennoscandiaalkaline
DS200612-0098
2005
Lahiri, A.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
DS200412-1080
2004
Lahiri-Dutt, K.Lahiri-Dutt, K.Informality in mineral resource management in Asia: raising questions relating to community economics and sustainable developmenNatural Resources Forum, Vol. 28, 4, May, pp. 123-132.AsiaSocio-economics - not specific to diamonds
DS1990-0590
1990
Lahmeyer, B.Gotze, H-J., Lahmeyer, B., Schmidt, S., Strunk, S., Araneda, M.Central Andes gravity dat a baseEos, Vol. 71, No. 16, April 17, pp. 401, 406-407Andes, Chile, ArgentinaGeophysics- gravity, Database
DS201805-0952
2017
Lahna, A.A.Ikenne, M., Lahna, A.A., Soderlund, U., Tassinar, C.C.G., Ernst, R.E., Pin, Ch., Youbi, N., El Aouli, EH., Hafid, A., Admou, H., Mata, J., Bouougri, EH., Boumehdi, M.A.New Mesoproterozoic age constraints for the Taghdout Group, Anti-Atlas ( Morocco): toward a new lithostratigra[hic framework for the Precambrian in the NW margin of the West African Craton.The First West African Craton and Margins International Workshop WACMA, Held Apr. 24-29. 1p. AbstractAfrica, Moroccogeochronology
DS1985-0068
1985
Lahner, L.Bluemel, G., Lahner, L.Minas Gerais, Brasil; Myths and Realities.(in German)Geologische Blaetter Fuer Nordost Bayern Und Angrenzende Gebiete, Vol. 34-35, pp. 735-754BrazilDiamonds Discussed, Overview
DS200612-0757
2005
Lahti, I.Lahti, I., Korja, T., Kaikkonen, P., Vaittinen, K.Decomposition analysis of the BEAR magnetotelluric data: implications for the upper mantle conductivity in the Fennoscandian Shield.Geophysical Journal International, Vol. 163, 3, Dec. pp. 900-914.Europe, Fennoscandia, Finland, SwedenGeophysics - magnetotelluric
DS201212-0742
2012
Lahti, I.Vaittinen, K., Korja, T., Kaikkonen, P., Lahti, I., Smirnov, M.Yu.High resolution magnetotelluric studies of the Archean Proterozoic border zone in the Fennoscandian shield, FinlandGeophysical Journal International, inpress availableEurope, FinlandGeophysics, magetics
DS200612-0758
2005
Lahti, S.I.Lahti, S.I.Orbicular rocks in Finland..... brief mentions of peridotites.Geological Survey of Finland, 176p.Europe, FinlandBook - occurrences, features, terminology - not diamond
DS1997-0642
1997
Lahtinen, R.Lahtinen, R., Huhma, H.Isotopic and geochemical constraints on the evolution of 1.93 - 1.79 Ga Svecofennian crust and mantle.Precambrian Research, Vol. 82, No. 1-2, Mar. 1, pp. 13-34.FinlandGeochronology, Mantle
DS1997-0643
1997
Lahtinen, R.Lahtinen, R., Huhma, H.Isotopic and geochemical constraints on the evolution of the 1.93-1.79 Ga Svecofennian crust and mantle.Precambrian Research, Vol. 82, No. 1-2, March pp. 13-34.FinlandTectonics, crust, mantle, Geochronology
DS2000-0548
2000
Lahtinen, R.Lahtinen, R.Archean Proterozoic transition: geochemistry, provenance, tectonic setting of metasedimentary rocksPrecambrian Research, Vol. 104, No. 3-4, Nov.pp. 147-74.Finland, FennoscandiaTectonics
DS200612-1517
2005
Lahtinen, R.Weihed, P., Arndt, N., Billstrom, K., Duschesne, J-C., Eilu, P., Martinsson, O., Papunen, H., Lahtinen, R.Precambrian geodynamics and ore formation: the Fennoscandian shield.Ore Geology Reviews, Vol. 27, pp. 273-322.Europe, FennoscandiaMetallogeny - tectonics
DS201906-1311
2019
Lahtinen, R.Lahtinen, R., Huhma, H.A revised geodynamic model for the Lapland - Kola Orogen.Precambrian Research, Vol. 330, pp. 1-19.Europe, Fennoscandia, Russia, Kola Peninsulatectonics

Abstract: The Paleoproterozoic Lapland-Kola Orogen in Fennoscandia has been studied for decades and several plate tectonic models have been proposed including one-sided subduction zone, either towards SW or NW, or two opposite-verging subduction zones before the collision. Based on new structural and isotope data from Finland and recently published data from Russia, we propose a revised tectonic model for the Paleoproterozoic Lapland-Kola Orogen. The main components are foreland in the NE followed by cryptic suture, Inari arc, retro-arc basin and retro-arc foreland in the SW. The latter three constitute the Inari Orocline. Subduction towards present SW and subsequent arc magmatism (Inari arc) started at ca. 1.98?Ga followed by voluminous sedimentation in the deepening retro-arc basin. Underplating of a mid-ocean ridge caused flat subduction and magmatic flare at 1.92?Ga over a broad distance in the retro-arc basin. Rapid heating led to melting of the retro-arc basin sediments and voluminous amounts of granulite-facies diatexites formed. During collision (D1) at 1915-1910?Ma, large thrust nappes formed on the foreland. Deformation in the retro-arc basin is seen as recumbent folding and shearing of diatexites in the lower parts of the basin and thrusting of metatextite-diatexite packages in the upper parts. A post-collisional stage is seen as 1904?Ma appinites and decompression derived granites at 1.90-1.89?Ga. Renewed shortening (D2), due to far-field effects in SW at 1.88-1.87?Ga, led to thick-skin shortening of the Archean middle crust, large-scale crustal duplexing of already cooled granulites towards the retro-arc foreland and inclined upright folding of granulites in the opposite direction towards the Inari arc. A switch in the stress field from NE-SW to NW-SE led to orogen-parallel contraction and buckling started along a dextral strike-slip fault zone to form the Inari Orocline. Buckling is seen in the bending of pre-orocline fabrics and formation of syn-orocline fabrics: radial conical folds (D3), radial fractures, a strike-slip fault zone and thrusting at the hinge zone. The end-result is a mega-scale parallel multi-layer fold composed of the Inari arc, retro-arc basin and possibly also the heated retro-arc foreland.
DS2001-0639
2001
Lahtinen R.Kukkonen, I.T., Lahtinen R.Variation of radiogenic heat production rate in 2.8 - 1.8 Ga old rocks in the central Fennoscandian shield.Physics of the Earth and Planetary Interiors, Vol. 126, No. 3-4, Nov. 1, pp. 279-94.Finland, Sweden, Baltica, FennoscandiaGeothermometry
DS1997-0644
1997
Lahtinent, R.Lahtinent, R., Huhma, H.Isotopic and geochemical constraints on the evolution of the 1.93 and 1.79Ga Svecofennian crust and mantlePrecambrian Research, Vol. 82, pp. 13-34FinlandGeochronology, Geochemistry
DS2002-1757
2002
LaiYamamoto, J., Kagi, H., Kaneoka, Lai, Prikhodko,AraiFossil pressures of fluid inclusions in mantle xenoliths exhibiting rheology of mantle minerals...Earth and Planetary Science Letters, Vol.198,3-4,pp.511-19., Vol.198,3-4,pp.511-19.MantleSpectroscopy, Geobarometry - mantle minerals
DS2002-1758
2002
LaiYamamoto, J., Kagi, H., Kaneoka, Lai, Prikhodko,AraiFossil pressures of fluid inclusions in mantle xenoliths exhibiting rheology of mantle minerals...Earth and Planetary Science Letters, Vol.198,3-4,pp.511-19., Vol.198,3-4,pp.511-19.MantleSpectroscopy, Geobarometry - mantle minerals
DS202009-1676
2020
Lai, C-K.Zheng, H., Chen, H., Wu, C., Jiang, H., Gao, C., Kang, Q., Yang, C., Wang, D., Lai, C-K.Genesis of the supergiant Huayangchuan carbonatite-hosted uranium polymetallic deposit in the Qinling orogen, central China.Gondwana Research, Vol. 86, pp. 250-265.ChinaREE

Abstract: The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic deposit is situated in the Qinling Orogen, Central China. The deposit contains economic endowments of U, Nb, Pb, Se, Sr, Ba and REEs, some of which (e.g., U, Se, and Sr) reaching super-large scale. Pyrochlore, allanite, monazite, barite-celestite and galena are the major ore minerals at Huayangchuan. Uranium is mainly hosted in the primary mineral of pyrochlore, and the mineralization is mainly hosted in or associated with carbonatite dikes. According to the mineral assemblages and crosscutting relationships, the alteration/mineralization at Huayangchuan comprises four stages, i.e., pegmatite REE mineralization (I), main mineralization (II), skarn mineralization (III) and post-ore alteration (IV). Coarse-grained euhedral allanite is the main Stage I REE mineral, and the pegmatite-hosted REE mineralization (ca. 1.8 Ga) occurs mostly in the shallow-level of northwestern Huayangchuan, corresponding to the Paleoproterozoic Xiong'er Group volcanic rocks (1.80-1.75 Ga) in the southern margin of North China Block. Carbonatite-hosted Stage II mineralization contributes to the majority of U-Nb-REE-Ba-Sr resources, and is controlled by the Huayangchuan Fault. Stage II mineralization can be further divided into the sulfate mineralization (barite-celestite) (II-A), alkali-rich U mineralization (aegirine-augite + pyrochlore + uraninite + uranothorite) (II-B) and REE (allanite + monazite + chevkinite)-U (pyrochlore + uraninite) mineralization (II-C) substages. Stage II mineralization may have occurred during the Late Triassic Mianlue Ocean closure. Skarn mineralization contributed to the majority of Pb and minor U-REE (uraninite-allanite) resources at Huayangchuan, and is spatially associated with the Late Cretaceous-Early Jurassic (Yanshanian) Huashan and Laoniushan granites. We suggested that hydrothermal fluids derived from the Laoniushan and Huashan granites may have reacted with the Triassic carbonatites, and formed the Huayangchuan Pb skarn mineralization. The mantle-derived Triassic carbonatites may have been fertilized by the U-rich subducting oceanic sediments, and were further enriched through reacting with the Proterozoic U-REE-rich pegmatite wallrocks at Huayangchuan. Ore-forming elements were likely transported in metal complexes (F-, and ), and deposited with the dilution of the complex concentration. This may have formed the distinct vertical mineralization zoning, i.e., sodic fenite-related alkali-U mineralization at depths and potassic fenite-related REE-U mineralization at shallow level.
DS202012-2258
2020
Lai, C-k.Zheng, H., Chen, H., Wu, C., Jiang, H., Gao, C., Kang, Q., Yang, C., Wang, D., Lai, C-k.Genesis of the supergiant Huayanchuan carbonatite-hosted uranium-plymetallic deposit in the Qinling Orogen, central China.Gondwana Research, Vol. 86, pp. 250-265. pdfChinadeposit - Huayangchuan

Abstract: The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic deposit is situated in the Qinling Orogen, Central China. The deposit contains economic endowments of U, Nb, Pb, Se, Sr, Ba and REEs, some of which (e.g., U, Se, and Sr) reaching super-large scale. Pyrochlore, allanite, monazite, barite-celestite and galena are the major ore minerals at Huayangchuan. Uranium is mainly hosted in the primary mineral of pyrochlore, and the mineralization is mainly hosted in or associated with carbonatite dikes. According to the mineral assemblages and crosscutting relationships, the alteration/mineralization at Huayangchuan comprises four stages, i.e., pegmatite REE mineralization (I), main mineralization (II), skarn mineralization (III) and post-ore alteration (IV). Coarse-grained euhedral allanite is the main Stage I REE mineral, and the pegmatite-hosted REE mineralization (ca. 1.8 Ga) occurs mostly in the shallow-level of northwestern Huayangchuan, corresponding to the Paleoproterozoic Xiong'er Group volcanic rocks (1.80-1.75 Ga) in the southern margin of North China Block. Carbonatite-hosted Stage II mineralization contributes to the majority of U-Nb-REE-Ba-Sr resources, and is controlled by the Huayangchuan Fault. Stage II mineralization can be further divided into the sulfate mineralization (barite-celestite) (II-A), alkali-rich U mineralization (aegirine-augite + pyrochlore + uraninite + uranothorite) (II-B) and REE (allanite + monazite + chevkinite)-U (pyrochlore + uraninite) mineralization (II-C) substages. Stage II mineralization may have occurred during the Late Triassic Mianlue Ocean closure. Skarn mineralization contributed to the majority of Pb and minor U-REE (uraninite-allanite) resources at Huayangchuan, and is spatially associated with the Late Cretaceous-Early Jurassic (Yanshanian) Huashan and Laoniushan granites. We suggested that hydrothermal fluids derived from the Laoniushan and Huashan granites may have reacted with the Triassic carbonatites, and formed the Huayangchuan Pb skarn mineralization. The mantle-derived Triassic carbonatites may have been fertilized by the U-rich subducting oceanic sediments, and were further enriched through reacting with the Proterozoic U-REE-rich pegmatite wallrocks at Huayangchuan. Ore-forming elements were likely transported in metal complexes (F-, and ), and deposited with the dilution of the complex concentration. This may have formed the distinct vertical mineralization zoning, i.e., sodic fenite-related alkali-U mineralization at depths and potassic fenite-related REE-U mineralization at shallow level.
DS1989-0841
1989
Lai, D.Lai, D.An important source of 4 He (and 3 He) in diamondsEarth and Planetary Science Letters, Vol. 96, pp. 1-7GlobalDiamond morphology, Helium, Noble gases -helium isoto
DS1989-1624
1989
Lai, D.Wiens, R.C., Lai, D., Craig, H.Helium and carbon isotope ratios in Indian diamondsEos, Vol. 70, No. 43, October 24, p. 1411. AbstractIndiaGeochronology, Diamond
DS1990-0899
1990
Lai, D.Lai, D., Craig, H.Sorting out the helium isotopes in diamonds: primordial, cosmogenic and implanted componentsEos, Vol. 71, No. 28, July 10, p. 849. AbstractGlobalDiamond morphology, Noble gases -helium isoto
DS1994-1914
1994
Lai, D.Wiens, R.C., Lai, D., Rison, W., Wacker, J.F.Helium isotope diffusion in natural diamondsGeochimica et Cosmochimica Acta, Vol. 58, No. 7, April pp. 1747-1758.GlobalDiamond morphology, Natural diamonds
DS201312-0539
2013
Lai, J.Liang, Q., Meng, Y., Yan, C., Krasnicki, S., Lai, J., Hemawan, K., Shu,H., Popov, D., Yu,T., Yang, W., Mao, H., Hemley, R.Developments in synthesis, characterization, and application of large high-quality CVD single crystal diamond.Journal of Superhard Materials, Vol. 35, 4, pp. 195-213.TechnologyDiamond synthetics
DS201906-1340
2019
Lai, M.Qiao, X., Zhou, Z., Schwarz, D.T., Qi, L., Gao, J., Nong, P., Lai, M., Guo, K., Li, Y.Study of the differences in infrared spectra of emerald from different mining areas and the controlling factors.The Canadian Mineralogist, Vol. 57, pp. 65-79.Globalemerald genesis

Abstract: Natural emeralds from 11 mining areas were studied using an infrared spectrometer. The results showed different spectroscopic characteristics for emerald from different mine regions. Infrared absorption is mainly attributed to the vibration of Si-O lattice, channel water, alkaline cations, and molecules such as CO2, [Fe2(OH)4]2+, etc. Both near-infrared and mid-infrared spectra showed that the differences in band positions, intensities, and shapes are related to the mixed ratio of the two types of channel water. Accordingly, emerald and its mining regions can be divided into 3 types: H2O I, H2O II, and transition I-II. Furthermore, the study indicates that the relative amounts of the two different orientations of channel water molecules are mainly affected by the presence of (Mg + Fe)2+ in the host rock or in the mineralizing fluid. Therefore, the mineralization environment type (alkali-poor, alkali-rich, and transitional types) of emerald can be preliminarily identified from IR spectroscopy. This can be useful for determining the origin of emeralds.
DS201812-2837
2018
Lai, M.Y.Lai, M.Y.Spectroscopic analysis of yellow diamonds. ( Chidliak, Ekati, Qilalugaq)Thesis, Msc. University of Alberta, 142p. Pdf availableCanada, Nunavut, Northwest Territoriesdeposit - Chidliak, Ekati, Qilalugaq
DS202002-0199
2020
Lai, M.Y.Lai, M.Y., Breeding, C.M., Stachel, T., Stern, R.A.Spectroscopic features of natural and HPHT treated yellow diamonds. EkatiDiamonds & Related Materials, Vol. 101, 107642, 8p. PdfCanada, Northwest Territoriesdeposit - Ekati

Abstract: High pressure high temperature (HPHT) treatment has long been applied in the gem trade for changing the body colour of diamonds. The identification of HPHT-treated diamonds is a field of on-going research in gemological laboratories, as different parameters of treatment will result in either the creation or the destruction of a variety of lattice defects in diamonds. Some features that exist in treated diamonds can also be found in natural diamonds, and consequently must not be employed for the separation of treated and natural diamonds. In this research, we investigated the properties of 11 natural yellow diamonds (directly obtained from the Ekati Diamond Mine to ensure that they are untreated) before and after HPHT treatment, conducted at a temperature of 2100 °C and a pressure of 6 GPa for 10 min. We report spectroscopic data and fluorescence characteristics, collected using PL mapping, FTIR mapping and fluorescence imaging showing the distribution of lattice defects and internal growth structures. PL mapping indicates SiV defects exist in one of the nitrogen-rich natural diamonds prior to treatment. Silicon-related defects can also be created by HPHT treatment, and they seem to show a relationship with pre-existing NV- centres. SIMS analysis was conducted to confirm the presence of silicon in these diamonds. The increase in the hydrogen-related infrared absorption peak at 3107 cm-1 (VN3H) is very strong in some diamonds that do not form B-centres during treatment. NVH was observed in our HPHT-treated natural diamonds, so it is possible that this strong increase in VN3H suppresses the aggregation of A- to B-centres as the newly formed A-centres were captured by NVH lattice defects to form VN3H. HPHT-altered and HPHT-induced platelet peaks are different from their natural counterparts in peak width and shape. Strong green fluorescence over a large area of a diamond, which is linked to relatively high concentration of H3 centres, was produced after HPHT treatment. We are confident that the unusual platelet peaks and strong emission of H3 centres are reliable indicators for HPHT-treated diamonds as they are not observed in untreated natural diamonds.
DS202003-0347
2020
Lai, M.Y.Lai, M.Y., Stachel, T., Breeding, C.M., Stern, R.A.Yellow diamonds with colourless cores - evidence for episodic diamond growth beneath Chidliak and Ekati mine, Canada.Mineralogy and Petrology, in press available 13p. PdfCanada, Northwest Territoriesdeposit - Chidliak, Ekati

Abstract: Yellow diamonds from the CH-7 (Chidliak) and the Misery (Ekati Mine) kimberlites in northern Canada are characterised for their nitrogen characteristics, visible light absorption, internal growth textures, and carbon isotope compositions. The diamonds are generally nitrogen-rich, with median N contents of 1230 (CH-7) and 1030 at.ppm (Misery). Normally a rare feature in natural diamonds, single substitutional nitrogen (C centres) and related features are detected in infrared absorption spectra of 64% of the studied diamonds from CH-7 and 87% from Misery and are considered as the major factor responsible for their yellow colouration. Episodically grown diamonds, characterised by colourless cores containing some nitrogen in the fully aggregated form (B centres) and yellow outer layers containing C centres, occur at both localities. Carbon isotope compositions and N contents also are significantly different in such core and rim zones, documenting growth during at least two temporally distinct events and involving different diamond forming fluids. Based on their nitrogen characteristics, both the yellow diamonds and yellow rims must have crystallized in close temporal proximity (<<1 Ma) to kimberlite activity at CH-7 and Misery.
DS201312-0528
2013
Lai, X.Lai, X., Yang, X.Geochemical characteristics of the Bayan Obo giant REE Nb Fe deposit: constraints on its genesis.Journal of South American Earth Sciences, Vol. 41, pp. 99-112.ChinaDeposit - Bayan Obo
DS201702-0256
2017
Lai, X.Yang, X., Lai, X., Pirajno, F., Liu, Y., Mingxing, L., Sun, W.Genesis of the Bayan Obo Fe_REE-Nb formation in Inner Mongolia, North Chin a craton: a perspective review.Precambrian Research, Vol. 288, pp. 39-71.ChinaDeposit - Bayan Obo

Abstract: The Bayan Obo deposit in Inner Mongolia, North China Craton (NCC) is the largest rare-earth element (REE) resource in the world. Due to the complex element and mineral compositions and the activity of several geological events, the ore-forming mechanism is still controversial. Previous models are reviewed here to provide information for further investigation on the Bayan Obo deposit. In this study, we summarize all different types of Fe-REE-Nb mineralization using field observations and microscope work, in which we recognize 9 types of Fe-REE-Nb ores in the Bayan Obo ore district. By compiling and re-evaluating a large number of published geochemical data, this paper provides solid evidence that the Bayan Obo deposit formed through interaction between sedimentary rocks and carbonatite magmatism. From the results of our review, it can be conjectured that the formation of iron ores was originated from sedimentation (Pt1), whereas the formation of REE mineralized dolomite might be related to interaction and reaction between the carbonatite magmas and/or associated fluids with sedimentary carbonate rocks, with the REE-bearing carbonatite magmas having undergone intense fractionation enrichment process. The C-O-S-Fe-Mg isotopes indicate that the REE-Nb mineralization was derived from metasomatism (fenitic alteration) of sedimentary carbonate. A new model is proposed for this unique REE-Nb mineralization, which is related to the subduction of Siberian Craton beneath the North China Craton since Early Paleozoic period. We interpret that the Bayan Obo Fe-REE-Nb ore deposits and their massive barren host, H8 dolomite, were generated as a result of interaction of fluids expelled from a subcontinental lithospheric mantle (SCLM)-derived carbonatite magma with sedimentary carbonates.
DS201709-2021
2017
LaI, X.Li, J., Xhu, F., Dong, J., Liu, J., LaI, X., Chen, B., Meng, Y.Experimental investigations into the fate of subducted carbonates and origin of super deep diamonds.Goldschmidt Conference, abstract 1p.Mantlepetrology

Abstract: Carbonates are common rock-forming minerals in the Earth’s crust and act as sinks of atmospheric carbon dioxide. Subduction of hydrothermally altered oceanic lithosphere returns carbon to the interior, where more than three quarters of Earth’s carbon is stored. The contribution of subducted carbonates to the Earth's long-term deep carbon cycle is uncertain and has recently emerged as a topic of intense debate [1]. Moreover, mantle-slab interaction has been proposed as a mechanism to produce super-deep diamonds, thus questioning the use of certain mineral inclusions to infer lower-mantle origin [2]. Here we report new data on the chemical stability and reaction kinetics of carbonates in the mantle from multianvil and diamond-anvil-cell experiments. Our results suggest that carbon can be sequestered into deep Earth through reaction freezing and that the index minerals for super-deep diamonds are not reliable indicators for their formation depths.
DS201809-2085
2018
Lai, X.Sharma, S.K., Chen, B., Gao, J., Lai, X.Micro-Raman investigations of diamond genesis during slab-mantle interaction.Goldschmidt Conference, 1p. AbstractMantlediamond genesis

Abstract: Magnesite is proposed to be a major oxidized carbon storage phase in the mantle due to its wide P-T range of stability [1-2]. The presence of magnesite in the Earth's interior will depend on the redox state of the Earth's interior. Large part of the deep mantel is considered to be significantly reduced with considerable amount of FeO dispersed in rocks [3]. During slab-mantle interaction, subducted carbonates in the slab will undergo redox reactions with metallic Fe. However, the mechanism of this interaction is not well understood. In order to understand diamond genesis during the slabmantle interactions, we have conducted high-pressure and high-temperature experiments in a 2000-ton multi-anvil highpressure press on samples containing MgCO3 and iron foils (50 µm thick) in BN capsules. The samples under pressures from 10 to 16 GPa were heated to 1200-1700 K. The samples were quenched under pressure and the quenched samples were polished and then analyzed with multi-wavelength micro-Raman spectrometers using 785, 514.5 and 532 nm laser excitations. Micro-Raman investigations show that the iron foils reduce MgCO3 to various sp2 carbon phases, mainly graphite, followed by the transformation to diamond upon long-duration heating. The transformation to diamond is driven by the temperature. For example, in the Run number PL066 with staring material containing magnesite and two Fe foils heated to 1400 K at 10 GPa for 24 hrs, and quenched, the run products were [Mg,Fe]O, and diamond and graphite. The sample PL044 with staring material containing magnesite and three Fe foils heated to 1600 K at 14 GPa for 12 hrs, the run products were larger size (~10 µm) diamonds, iron carbide and small amount of graphite. Our results indicate that in slow subduction (T~1500 K) all carbonates will be converted in diamond and iron carbide. Under rapid subduction of the slab, the carbonate will survive and be carried to greater depth. The inclusions of [Mg,Fe]O in diamonds, however, do not necessarily indicate that this phase is of lower mantle origin.
DS201811-2587
2018
Lai, X.Lai, X., Zhu, F., Zhang, D., Hu, Y., Finkelstein, G.J., Dera, P., Chen, B.The high pressure anisotropic thermelestic properties of a potential inner core carbon bearing phase, Fe-C3, by single crystal X-ray diffraction.American Mineralogist, Vol. 103, pp. 1568-1574.Mantlecarbon

Abstract: Carbon has been suggested as one of the light elements existing in the Earth's core. Under core conditions, iron carbide Fe7C3 is likely the first phase to solidify from a Fe-C melt and has thus been considered a potential component of the inner core. The crystal structure of Fe7C3, however, is still under debate, and its thermoelastic properties are not well constrained at high pressures. In this study, we performed synchrotron-based single-crystal X-ray diffraction experiment using an externally heated diamond-anvil cell to determine the crystal structure and thermoelastic properties of Fe7C3 up to 80 GPa and 800 K. Our diffraction data indicate that Fe7C3 adopts an orthorhombic structure under experimentally investigated conditions. The pressure-volume-temperature data for Fe7C3 were fitted by the high-temperature Birch-Murnaghan equation of state, yielding ambient-pressure unit-cell volume V0 = 745.2(2) Å3, bulk modulus K0 = 167(4) GPa, its first pressure derivative K0' = 5.0(2), dK/dT = -0.02(1) GPa/K, and thermal expansion relation aT = 4.7(9) × 10-5 + 3(5) × 10-8 × (T - 300) K-1. We also observed anisotropic elastic responses to changes in pressure and temperature along the different crystallographic directions. Fe7C3 has strong anisotropic compressibilities with the linear moduli Ma > Mc > Mb from zero pressure to core pressures at 300 K, rendering the b axis the most compressible upon compression. The thermal expansion of c3 is approximately four times larger than that of a3 and b3 at 600 and 700 K, implying that the high temperature may significantly influence the elastic anisotropy of Fe7C3. Therefore, the effect of high temperature needs to be considered when using Fe7C3 to explain the anisotropy of the Earth's inner core.
DS201904-0805
2019
Lai, X.Zhu, F., Li, J., Liu, J., Lai, X., Chen, B., Meng, Y.Kinetic control on the depth of superdeep diamonds.Geophysical Research Letters, Vol. 46, 4, pp. 1984-1992.Mantlediamond genesis

Abstract: Superdeep diamonds originate from great depths inside Earth, carrying samples from inaccessible mantle to the surface. The reaction between carbonate and iron may be an important mechanism to form diamond through interactions between subducting slabs and surrounding mantle. Interestingly, most superdeep diamonds formed in two narrow zones, at 250-450 and 600-800 km depths within the ~2,700-km-deep mantle. No satisfactory hypothesis explains these preferred depths of diamond formation. We measured the rate of a diamond forming reaction between magnesite and iron. Our data show that high temperature promotes the reaction, while high pressure does the opposite. Particularly, the reaction slows down drastically at about 475(±55) km depth, which may explain the rarity of diamond formation below 450 km depth. The only exception is the second zone at 600-800 km, where carbonate accumulates and warms up due to the stagnation of subducting slabs at the top of lower mantle, providing more reactants and higher temperature for diamond formation. Our study demonstrates that the depth distribution of superdeep diamonds may be controlled by reaction rates.
DS202002-0200
2019
Lai, X.Lai, X., Yang, X.U-Pb ages and Hf isotope of zircons from a carbonatite dyke in the Bayan Obo Fe-REE deposit in Inner Mongolia: its geological significance.Acta Geologica Sinica, Vol. 93, 6, pp. 1783-1796.China, MongoliaREE

Abstract: Detailed studies on U-Pb ages and Hf isotope have been carried out in zircons from a carbonatite dyke associated with the Bayan Obo giant REE-Nb-Fe deposit, northern margin of the North China Craton (NCC), which provide insights into the plate tectonic in Paleoproterozoic. Analyses of small amounts of zircons extracted from a large sample of the Wu carbonatite dyke have yielded two ages of late Archaean and late Paleoproterozoic (with mean 207Pb/206Pb ages of 2521±25 Ma and 1921±14 Ma, respectively). Mineral inclusions in the zircon identified by Raman spectroscopy are all silicate minerals, and none of the zircon grains has the extremely high Th/U characteristic of carbonatite, which are consistent with crystallization of the zircon from silicate, and the zircon is suggested to be derived from trapped basement complex. Hf isotopes in the zircon from the studied carbonatite are different from grain to grain, suggesting the zircons were not all formed in one single process. Majority of ?Hf(t) values are compatible with ancient crustal sources with limited juvenile component. The Hf data and their TDM2 values also suggest a juvenile continental growth in Paleoproterozoic during the period of 1940-1957 Ma. Our data demonstrate the major crustal growth during the Paleoproterozoic in the northern margin of the NCC, coeval with the assembly of the supercontinent Columbia, and provide insights into the plate tectonic of the NCC in Paleoproterozoic.
DS201212-0393
2012
Lai, X-D.Lai, X-D., Yang, X-Y.Geochemical characteristics of the Bayan Obo giant REE-Nb-Fe deposit: constraints on its genesis.Journal of South American Earth Sciences, in press available 58p.ChinaCarbonatite
DS200912-0716
2009
Lai, Y.Song, S., Su, L., Niu, Y., Lai, Y., Zhang, L.CH4 inclusions in orogenic harzburgite: evidence for reduced slab fluids and implication for redox melting in mantle wedge.Geochimica et Cosmochimica Acta, Vol. 73, 6, pp. 1737-1754.MantleSubduction
DS1992-0354
1992
Lai ShaocongDeng Jinfu, Zhao Hailing, Lai Shaocong, Molan, E., Lou Zaohua, Mo XuanxueThe mantle plume beneath the northern part of Chin a continentInternational Symposium Cenozoic Volcanic Rocks Deep seated xenoliths China and its, Abstracts pp. 15ChinaMantle, Plume
DS1982-0320
1982
Lai.Keller, G.R., Kruger, J.M., Schneider, R.V., Aiken, C.L.V., Lai.Regional Geophysical Studies of the Southern Oklahoma Aulocogen and Ouachita SystemGeological Society of America (GSA), Vol. 14, No. 3, P. 115, (abstract.).OklahomaMid-continent, Geophysics
DS201811-2619
2018
Laia, S.Xu, J., Melgarejo, J.C., Castillo, O., Montgarri, A., Laia, S., Santamaria, J.Ilmenite generations in kimberlite from Banankoro, Guinea. ConakryNeues Jahrbuch fur Mineralogie, doi:.org/10.1127/njma/2018/0096Africa, Guineadeposit - Banakoro

Abstract: A complex mineral sequence in a kimberlite from the Banankoro Cluster (Guinea Conakry) has been interpreted as the result of magma mixing processes. The composition of the early generations of phlogopite and spinel suggest direct crystallisation of a kimberlitic magma. However, the compositional trends found in the late generations of phlogopite and spinels could suggest magma mixing. In this context, four ilmenite generations formed. The first generations (types 1 and 2) are geikielitic and are associated with spinel and phlogopite which follow the kimberlitic compositional trends. They are interpreted as produced by crystallization from the kimberlite magma. A third generation of euhedral tabular Mg-rich ilmenite (type 3) formed during the interval between two generations of serpentine. Finally, a late generation of Mn-rich ilmenite (type 4) replaces all the Ti-rich minerals and is contemporaneous with the last generation of serpophitic non-replacing serpentine. Therefore, the formation of type 3 and type 4 ilmenite took place after the crystallization of the groundmass, during late hydrothermal process. Our results suggest a detailed textural study is necessary when use Mg-rich and Mn-rich ilmenites as KIMs.
DS1998-1002
1998
Laiba, A.A.Mikhalsky, E.V., Laiba, A.A., Surina, N.P.The Lambert Province of alkaline basic and alkaline ultrabasic rocks of East Antarctica: geochemistry...Petrology, Vol 6, No. 5, Sept-Oct. p. 466-479.GlobalAlkaline rocks
DS200812-0103
2008
Laiba, A.A.Belyatsky, B.V., Antonov, A.V., Rodionov, N.V., Laiba, A.A., Sergeev, S.A.Age and composition of carbonatite kimberlite dykes in the Prince Charles Mountains, East Antarctica9IKC.com, 3p. extended abstractAntarcticaCarbonatite
DS200912-0422
2009
Laiginhas, F.Laiginhas, F., Pearson, D.G., Phillips, D., Burgess, R., Harris, J.W.Re Os and 40Ar 39Ar isotope measurements of inclusions in alluvial diamonds from the Ural Mountains: constraints on diamond genesis and eruption ages.Lithos, in press availableRussia, UralsGeochronology
DS201812-2831
2018
Laiginhas, F.Krebs, M.Y., Pearson, D.G., Stachel, T., Laiginhas, F., Woodland, S., Chinn, I., Kong, J.A common parentage - Low abundance trace element data of gem diamonds reveals similar fluids to fibrous diamonds. ( silicate/sulphide)Lithos, doi.org/10.1016/ jlithos.2018.11.025 49p.Canada, Ontario, Attawapiskat, Africa, South Africadeposit - Victor, Finsch, Newlands

Abstract: Quantitative trace element data from high-purity gem diamonds from the Victor Mine, Ontario, Canada as well as near-gem diamonds from peridotite and eclogite xenoliths from the Finsch and Newlands mines, South Africa, acquired using an off-line laser ablation method show that we see the same spectrum of fluids in both high-purity gem and near-gem diamonds that was previously documented in fibrous diamonds. “Planed” and “ribbed” trace element patterns characterize not only the high-density fluid (HDF) inclusions in fibrous diamonds but also in gem diamonds. Two diamonds from two Finsch harzburgite xenoliths show trace element patterns similar to those of saline fluids, documenting the involvement of saline fluids in the precipitation of gem diamonds, further strengthening the link between the parental fluids of both gem and fibrous diamonds. Differences in trace element characteristics are evident between Victor diamonds containing silicate inclusions compared with Victor diamonds containing sulphide inclusions. The sulphide-bearing diamonds show lower levels of inter-element fractionation and more widely varying siderophile element concentrations - indicating that the silicate and sulphide-bearing diamonds likely formed by gradations of the same processes, via melt-rock reaction or from a subtly different fluid source. The shallow negative LREEN-HREEN slopes displayed by the Victor diamonds establish a signature indicative of original derivation of the diamond forming agent during major melting (~10% melt). Consequently, this signature must have been passed on to HDFs separating from such silicate melts.
DS201902-0288
2019
Laiginhas, F.Krebs, M.Y., Pearson, D.G., Stachel, T., Laiginhas, F., Woodland, S., Chinn, I., Kong, J.A common parentage low abundance trace element data of gem diamonds reveals similar fluids to fibrous diamonds.Lithos, Vol. 324, 1, pp. 356-370.Canada, Ontario, Africa, South Africadeposit - Victor, Finsch, Newlands

Abstract: Quantitative trace element data from high-purity gem diamonds from the Victor Mine, Ontario, Canada as well as near-gem diamonds from peridotite and eclogite xenoliths from the Finsch and Newlands mines, South Africa, acquired using an off-line laser ablation method show that we see the same spectrum of fluids in both high-purity gem and near-gem diamonds that was previously documented in fibrous diamonds. "Planed" and "ribbed" trace element patterns characterize not only the high-density fluid (HDF) inclusions in fibrous diamonds but also in gem diamonds. Two diamonds from two Finsch harzburgite xenoliths show trace element patterns similar to those of saline fluids, documenting the involvement of saline fluids in the precipitation of gem diamonds, further strengthening the link between the parental fluids of both gem and fibrous diamonds. Differences in trace element characteristics are evident between Victor diamonds containing silicate inclusions compared with Victor diamonds containing sulphide inclusions. The sulphide-bearing diamonds show lower levels of inter-element fractionation and more widely varying siderophile element concentrations - indicating that the silicate and sulphide-bearing diamonds likely formed by gradations of the same processes, via melt-rock reaction or from a subtly different fluid source. The shallow negative LREEN-HREEN slopes displayed by the Victor diamonds establish a signature indicative of original derivation of the diamond forming agent during major melting (~10% melt). Consequently, this signature must have been passed on to HDFs separating from such silicate melts.
DS201803-0439
2006
Laiginhas-Fernando, A.T.P.Correia Eugenio, A., Laiginhas-Fernando, A.T.P.Garnets from the Camafuca Camazambo kimberlite.Anais da Academia Brasileira de Ciencas, Vol. 78, 2, pp. 309-315.Africa, Angoladeposit - Camafuca

Abstract: This work presents a geochemical study of a set of garnets, selected by their colors, from the Camafuca-Camazambo kimberlite, located on northeast Angola. Mantle-derived garnets were classified according to the scheme proposed by Grütter et al. (2004) and belong to the G1, G4, G9 and G10 groups. Both sub-calcic (G10) and Ca-saturated (G9) garnets, typical, respectively, of harzburgites and lherzolites, were identified. The solubility limit of knorringite molecule in G10D garnets suggests they have crystallized at a minimum pressure of about 40 to 45 kbar (4-4.5 GPa). The occurrence of diamond stability field garnets (G10D) is a clear indicator of the potential of this kimberlite for diamond. The chemistry of the garnets suggests that the source for the kimberlite was a lherzolite that has suffered a partial melting that formed basaltic magma, leaving a harzburgite as a residue.
DS1996-1526
1996
Laili, J.Wen, Su, Shutong, Xu, Laili, J., Yican, LiuCoesite from quartz jadeitite in the Dabie Mountains, eastern ChinaMineralogical Magazine, Vol. 60, pp. 659-662.ChinaCoesite
DS200812-0625
2008
Laine, H.M.Laine, H.M., O'Brien, H.E.Alteration and primary kimberlite rock type classification for Lahtojoki kimberlite, Finland.9IKC.com, 3p. extended abstractEurope, FinlandDeposit - Lahtojoki
DS1970-0118
1970
Laing, E.M.Laing, E.M.Report on the Geology of Part of the Nimini Hills Schist Belt and Associated Sialic Rocks.Geological Survey SIERRA LEONE., UNPUBL. ReportWest Africa, Sierra LeoneGeology
DS1998-0825
1998
Laing, G.Laing, G.Discovery and evaluation of the Jericho kimberlites, NorthwestTerritories.Calgary Mining Forum, Apr. 8-9, p. 26. abstractNorthwest TerritoriesDeposit - Jericho, Lytton Minerals
DS1999-0391
1999
Laing, G.Laing, G.Tahera Corporation: developing the Jericho kimberlite field8th. Calgary Mining forum, 1p. abstractNorthwest TerritoriesNews item
DS200812-0626
2008
Laing, T.Laing, T.Diamonds are forever.... Eira Thomas and Ellen Clements are interviewed.Mining and Exploration ( BC), Summer. p. 4-5.CanadaNews item - history
DS2003-1515
2003
Lai-Xiang, L.Xue-Cheng, Y., Klemperer, S.L., Wen-Bang, T., Lai-Xiang, L., Chetwin, E.Crustal structure and exhumation of the Dabie Shan ultrahigh pressure orogen, easternGeology, Vol. 31, 5, pp. 435-8.ChinaGeophysics - seismics, UHP - ultra high pressure
DS200412-2164
2003
Lai-Xiang, L.Xue-Cheng, Y., Klemperer, S.L., Wen-Bang, T., Lai-Xiang, L., Chetwin, E.Crustal structure and exhumation of the Dabie Shan ultrahigh pressure orogen, eastern China, from seismic reflection profiling.Geology, Vol. 31, 5, pp. 435-8.ChinaGeophysics - seismics UHP - ultra high pressure
DS1991-0948
1991
Laj, C.Laj, C., Mazaud, A., Weeks, R., Fuller, M., Herrero Bervera, E.Geomagnetic reversal pathsNature, Vol. 351, June 6, p. 447GlobalGeophysics, Geomagnetics, Paleomagnetics
DS1997-0645
1997
Lajaunie, C.Lajaunie, C., Courrioux, G., Manuel, L.Foliation fields and 3D cartography in geology: principles of a method based on potential interpolationMath. Geol, Vol. 29, No. 4, pp. 571-584GlobalGeostatistics, Kriging
DS2000-0525
2000
Lajoki, K.Korobeinikov, A.N., Lajoki, K., Gehor, S.Nepheline bearing feldspar syenite (pulaskite) Khibin a pluton, Kola Peninsula -petrological investigationJournal of Asian Earth Science, Vol. 18, No.2, Apr. pp.205-12.Russia, Kola PeninsulaPetrology, Pulaskite
DS201112-1045
2011
Lake, G.Tien, Y., Zhou, Y., Sigloch, K., Nolet, G., Lake, G.Structure of North American mantle constrained by simultaneous inversion of multiple frequency SH, SS and Love waves.Journal of Geophysical Research, Vol. 116, B2, B02307..MantleGeophysics - seismics
DS1860-0667
1890
Lake, P.Lake, P.The Supposed Matrix of the Diamond at Wajrakarur, MadrasIndia Geological Survey Records, Vol. 23, PP. 69-72.India, Andhra PradeshPetrography
DS1992-0906
1992
Lakefield ResearchLakefield ResearchMineralogy: diamond exploration samples. Brochure outlining procedures they use and fee structure for microdiamond extraction.briefLakefield Research, 2p. ( total 1p. info)CanadaBrochure, Lakefield Research
DS1900-0779
1909
Lakes, A.Lakes, A.Precious Stones 1909Mining Science., Vol. 60, Nov. 4TH. PP. 414-416.United States, CanadaGemstones
DS200712-0478
2007
Lakes, R.S.Jaglinski, T., Kochmann, D., Stone, D., Lakes, R.S.Composite materials with viscoelastic stiffness greater than diamond.Science, No. 5812, Feb. 2, pp. 620-621.TechnologyChemistry
DS201806-1239
2018
Lakhotia, S.C.Patwardhan, B., Nagarkar, S., Gadre, S.R., Lakhotia, S.C., Katoch, V.M., Moher, D.A critical analysis of the 'UGC' approved list of journals.Current Science, Vol. 114, 6, Mar. 25, pp. 1299-1303.Indialegal

Abstract: Scholarly journals play an important role in maintaining the quality and integrity of research by what they publish. Unethical practices in publishing are leading to an increased number of predatory, dubious and low-quality journals worldwide. It has been reported that the percentage of research articles published in predatory journals is high in India. The University Grants Commission (UGC), New Delhi has published an 'approved list of journals', which has been criticized due to inclusion of many substandard journals. We have developed a protocol with objective criteria for identifying journals that do not follow good publication practices. We studied 1336 journals randomly selected from 5699 in the university source component of the 'UGC-approved list'. We analysed 1009 journals after excluding 327 indexed in Scopus/Web of Science. About 34.5% of the 1009 journals were disqualified under the basic criteria because of incorrect or non-availability of essential information such as address, website details and names of editors; another 52.3% of them provided false information such as incorrect ISSN, false claims about impact factor, claimed indexing in dubious indexing databases or had poor credentials of editors. Our results suggest that over 88% of the non-indexed journals in the university source component of the UGC-approved list, included on the basis of suggestions from different universities, could be of low quality. In view of these results, the current UGC-approved list of journals needs serious reconsideration. New regulations to curtail unethical practices in scientific publishing along with organization of awareness programmes about publication ethics at Indian universities and research institutes are urgently needed.
DS201012-0391
2010
Lakin, D.A.Kislyakov, V.E., Korzon, O.A., Lakin, D.A.Shelf placer deposits: a new technology for winter mining.Russian Geology and Geophysics, Vol. 51, pp. 143-145.RussiaMining - coolants related to placer gold deposits
DS201412-0941
2013
Lakshimi, V.N.Vani, T., Lakshimi, V.N., Ramakrishnarao, M.V., Keller, G.R., Subbarao, K.V.Integration of geophysical and geological dat a of kimberlites in Narayanpet-Maddur field, Andhra Pradesh, India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 229-240.India, Andhra PradeshDeposit - Narayanpet- Maddur
DS1970-0268
1971
Lakshmanan, S.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
DS1990-0900
1990
Lakshmanan, V.I.Lakshmanan, V.I., Miller, J.D.Advanced materials- application of mineral and metallurgical processingAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Book, 400p. approx. 60.00GlobalMineral processing, Advanced materials
DS200512-0051
2005
Lakshmi, M.P.Babu, H.V.R., Lakshmi, M.P.Aeromagnetic image of a part of peninsular India and its relation to geology and geophysics.Exploration Geophysics, Vol. 36, 2, pp. 250-258.India, AsiaGeophysics - magnetics (not specific to diamonds)
DS200712-0630
2007
Lakshtanov, D.Litasov, K.D., Kagi, H., Shatskiy, A., Lakshtanov, D., Bass, J.D., Ito, E.High hydrogen solubility in Al rich stishovite and water transport in the lower mantle.Earth and Planetary Science Letters, Vol. 262, 3-4, Oct. 30, pp. 620-634.MantleWater
DS200612-0097
2006
Lakshtanov, D.L.Bass, J.D., Sanchez-Valle, C., Lakshtanov, D.L., Brenizer, J., Wang, J., Matas, J.Elastic properties of high pressure phases and implications for the temperature and mineralogy of Earth's lower mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleGeothermometry
DS200612-0824
2006
Lakshtanov, D.L.Litasov, K.D., Ohtain, E., Kagi, H., Lakshtanov, D.L., Bass, J.D.Hydrogen solubility in Al rich stidhovite and water transport to the lower mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 23. abstract only.MantleWater
DS1987-0392
1987
Lal, D.Lal, D., Nishizumi, K., Klein, J., Middleton, R., Craig, H.Cosmogenic 13Be in Zaire alluvial diamonds: implications for Helium contents of diamondsNature, Vol. 328, No. 6126, July 9, pp. 139-141Democratic Republic of CongoDiamond, Mineral Chemistry
DS1989-0842
1989
Lal, D.Lal, D., Craig, H., Wacker, J.F., Poreda, R.He-3 diamonds- the cosmogenic component (letter)Geochimica et Cosmochimica Acta, Vol. 53, No. 2, Feb. pp. 569-574GlobalDiamond morphology
DS1990-1148
1990
Lal, D.Ozima, M., Lal, D.Comment on an important source of 4He (and 3He) in diamonds, by D. Lal. and reply by LalEarth and Planetary Science Letters, Vol. 101, No. 1, November pp. 107-111GlobalDiamonds, helium
DS1990-1556
1990
Lal, D.Wiens, R., Lal, D., Craig, H.Helium and carbon isotopes in Indian diamondsGeochimica et Cosmochimica Acta, Vol. 54, pp. 2587-2591IndiaGeochronology, Diamond inclusions - H and
DS1996-0801
1996
Lal, D.Lal, D.On nuclear studies of processes and time scales in the evolution of an alluvial fan.Geochemistry International, Vol. 33, No. 5, pp. 77-93.RussiaAlluvials, Geomorphology, cosmic ray geophysics
DS1990-1368
1990
Lal, K.Singh, B.P., Gupta, S.K., Dhawan, U., Lal, K.Characterization of synthetic diamonds by EPR and X-raydiffractiontechniquesJournal of Material Science, Vol. 25, No. 28, February pp. 1487-1490GlobalDiamond synthesis, EPR and X-ray diffraction
DS200812-0627
2008
Lal, R.K.Lal, R.K.An updated calibration of garnet clinopyroxene Fe Mg exchange geothermometer: application to mantle xenoliths in kimberlite and related rocks.Indian Dykes: editors Srivastava, Sivaji, Chalapathi Rao, pp. 354-366.IndiaKimberlite geothermometry
DS200412-0669
2004
Lalancette, J.Girard, R., Parent,M., Aubin, A., Belley, J.M., Lalancette, J.Glacial dispersion of lithological indicators in the Otish Mountain area.Quebec Exploration Conference, Canada, Quebec, Otish MountainsGeochemistry, geomorphology
DS1860-0805
1893
Lalanne, E.Lalanne, E.Les Mines de Diamant du Cap (1893) - the Diamond Mines of the CapeScience Illustrated., Vol. 11, Jan.14TH. PP. 114-115.Africa, South AfricaGeology
DS200612-0759
2005
Lalemant, H.G.A.Lalemant, H.G.A., Sisson, V.B.Caribbean South American plate interactions, Venezuela.Geological Society of America, No. 394, 335p.South America, VenezuelaBook - eclogites,allochthonous belts - not specific diamonds
DS1995-1045
1995
Lalleman, S.Lalleman, S.High rates of arc consumption by subduction processes: some consequencesGeology, Vol. 23, No. 6, June pp. 551-554Japan, PeruMantle, Subduction, arc consumption
DS1995-1046
1995
Lallemand, S.Lallemand, S.High rates of arc consumption by subduction processes: some consequencesGeology, Vol. 23, No. 6, June pp. 551-554.Japan, PeruSubduction
DS200512-0430
2005
Lallemand, S.Heuret, A., Lallemand, S.Plate motions, slab dynamics and back arc deformation.Physics of the Earth and Planetary Interiors, Vol. 149, 1-2, March 15, pp. 31-51.MantleSubduction
DS200512-0596
2005
Lallemand, S.Lallemand, S., Heuret, A., Boutelier, D.On the relationship between slab dip, back arc stress, upper plate absolute motion, and crustal nature in subduction zones.Geochemistry, Geophysics, Geosystems: G3, Vol. 6, Q12J14, doi:10.1029/2005 GC000917MantleSubduction, geodynamics
DS200812-0373
2008
Lallemand, S.Funiciello, F., Faccenna, C., Heuret, A., Lallemand, S., Di Guiseppe, E., Becker, T.W.Trench migration, net rotation and slab mantle decoupling.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 233-240.MantleSubduction
DS200812-0628
2008
Lallemand, S.Lallemand, S., Heuret, A., Faccenna, C., Funiciello, F.Subduction dynamics as revealed by trench migration.Tectonics, Vol. 27, TC3014MantleSubduction
DS200812-1271
2008
Lallemand, S.Wu, B., Conrad, C.P., Heuret, A., Lithgow Bertollini, C., Lallemand, S.Reconciling strong slab pull and weak plate bending: the plate motion constraint on the strength of mantle slabs.Earth and Planetary Science Letters, Vol. 272, 1-2, pp. 412-421.MantleSubduction
DS200812-1273
2008
Lallemand, S.Wu, C., Conrad, C.P., Heuret, A., Lithgow-Bertelloni, C., Lallemand, S.Reconciling strong slab pull and weak plate bending: the plate motion constraint on the strength of mantle slabs.Earth and Planetary Science Letters, Vol. 272, 1-2, July 30, pp. 412-421.MantleSubduction
DS201012-0190
2010
Lallemand, S.Faccenna, C., Becker, T.W., Lallemand, S., Lagabrielle, Y., Funiciello, F., Piromallo, C.Subduction triggered magmatic pulses: a new class of plumes?Earth and Planetary Science Letters, Vol. 299, 1-2, Oct. 15, pp. 54-68.MantleMagmatism
DS1993-0895
1993
Lallemant, S.Le Pichon, X., Henry, P., Lallemant, S.Accretion and erosion in subduction zones: the role of fluidsAnnual Review of Earth and Planetary Sciences, Vol. 21, pp. 307-332MantleTectonics
DS200512-0617
2005
Lallukka, H.M.Lehtonen, M.L., Pakkanen, L.K., Johanson, B.S., Lallukka, H.M.EMP analyses of kimberlite indicator minerals from Pipe 7 and Dyke 16 kimberlites and the basal till surrounding them.Geological Survey of Finland, Open File M 41.2/2005/2.Europe, FinlandGeochemistry
DS1994-0105
1994
Lally, J.H.Barker, D.J., Lally, J.H.Use of geostatistics to model geology -vein distribution in a complex pegmatite type depositInstitute of Mining and Metallurgy (IMM) Bulletins, pp. B 97-102GlobalGeostatistics, Pegmatites
DS200612-0801
2006
Lalonde, A.Lenz, D., Lalonde, A., Salvi, S., Paquette, J.Alkaline igneous systems: dissecting magmatic to hydrothermal mineralizing processes.Mineralogical Association of Canada, www.gacmac2006.caCanada, QuebecTechnical meeting - volcanism, alkaline rocks
DS1981-0258
1981
Lalonde, A.E.Lalonde, A.E.The Baie des Mountons Syenitic Complex, la Tabatiere, QuebecMsc. Thesis, Mcgill University, Canada, QuebecBlank
DS1994-0973
1994
Lalonde, A.E.Lalonde, A.E., Rancourt, D.G., Chao, G.Y.iron bearing trioctahedral micas from Mont Saint Hilaire, QuebecGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p.QuebecMineralogy, Mont Saint Hilaire
DS1996-0802
1996
Lalonde, A.E.Lalonde, A.E., Rancourt, D.G., Chao, G.Y.iron bearing trioctahedral micas from Mont Saint Hilaire Quebec, CanadaMineralogical Magazine, Vol. 60, pp. 447-460.QuebecAlkaline rocks, Deposit -Mont St. Hilaire region
DS1985-0378
1985
LamLam, CHI-KIN, Yarger, H.L.Preliminary Investigation of New Kansas Gravity MapGeological Society of America (GSA), Vol. 17, No. 5, MARCH P. 297. (abstract.).United States, Central States, KansasGravity, Geophysics
DS1988-0395
1988
Lam, C.Lam, C., Yarger, H.The structure of the central North American rift system in Kansas as interpreted from gravity dataGeological Society of America Abstracts with Program, Vol. 20, No. 2, January p. 121. Sth. Central, LawrenceKansasMid continent
DS1989-0843
1989
Lam, C.Lam, C.New gravity dat a in northeastern IndianaGeological Society of America (GSA) Abstract Volume, Vol. 21, No. 4, p. 39. (abstract.)Indiana, MidcontinentGeophysics
DS1983-0640
1983
Lam, C.K.Yarger, H.L., Lam, C.K.New Gravity Dat a in Eastern KansasGeological Society of America (GSA), Vol. 15, No. 6, P. 724. (abstract.)KansasMid Continent
DS1986-0479
1986
Lam, C.K.Lam, C.K., Yarger, H.L.Kansas basement age terrane boundary from gravity and magnetic dataGeological Society of America (GSA) Abstact Volume, Vol. 18, No. 6, p. 664. (abstract.)GlobalGeochronology, Geophysics
DS1989-0844
1989
Lam, H-L.Lam, H-L.On the prediction of low frequency geomagnetic pulsations for geophysicalprospectingGeophysics, Vol. 54, No. 5, May pp. 635-642GlobalGeophysics, electromagnetic
DS2000-0969
2000
LaMarUSGS, Hearns, P., Hare, Schruber, Sherrill, LaMarGlobal GIS database: digital atlas of Central and South AmericaUsgs, DDS-62-A ( CD ROM)Central America, South AmericaDigital Data series - atlas
DS201902-0289
2018
Lamarque, G.Lamarque, G., Agostinetti, N.P., Julia, J., Evain, M.Joint interpretation of SKS-splitting measurements and receiver function data for detecting seismic anisotropy in the upper mantle: feasibility and limitations.AGU, 1p. abstract Mantlegeophysics -seismic

Abstract: Measuring seismic anisotropy within the Earth is essential as it constitutes a proxy for inferring upper mantle deformation related to mantle flow, that develops preferred orientations of the minerals in response to tectonic strain. The most-used method to detect anisotropy beneath a seismic station is the measurement of teleseismic SKS wave splitting on two horizontal recordings, i.e. measuring the delay time (dt) between two fast- and slow- polarized shear-waves and the orientation of polarization (F). This technique allows a integrative measurement (SKS data, hereinafter) that estimates the average F and dt along the entire SKS ray-path. Despite its importance for large-scale anisotropy within the upper mantle, the analysis of SKS data suffers from several limitations : (1) SKS data become difficult to interpret in regions where several anisotropic layers occur; (2) SKS waves fail to provide robust information about anisotropy related to thin layers; and (3) SKS data can investigate rock volumes with an horizontal symmetry axis only. During the last decade a new method, called harmonic decomposition of teleseismic Receiver Functions (RFs) has been developed in order to detect more complex anisotropic layering. This methodology is based on the extraction of back-azimuth harmonics of the RF dataset. Briefly, it constitutes a tool to appreciate the value of F and dt at every depth-level affording a detailed study of the rock anisotropy with both plunging and horizontal symmetry axis. RFs studies are however commonly limited to the first 10-15s of the signal and do not sample the deepest anisotropy. In this work we investigate in details both SKS data and RFs harmonic decomposition for a pool of stations deployed in northeastern Brasil, in order to understand how results from the analysis of these two observables can be jointly interpreted. We focus our study on the permanent station RCBR and on temporary seismic stations deployed in the area. We show that comparison and/or joint interpretation is not straightforward as both results can vary according to the amount of data available and their distribution in back-azimuth, and filtering. However, tacking into account those issues, the integration of these two observables represent a great step-forward for robust detection of upper mantle anisotropy.
DS1975-0107
1975
Lamb, G.C.Howard, J.M., Lamb, G.C.Transition Element Geochemistry of the Potash Sulfur Springs Intrusion, Garland County, Arkansaw.Geological Society of America (GSA), Vol. 7, No. 2, P. 174. (abstract.).United States, Gulf Coast, Arkansas, Garland CountyGeochemistry
DS201708-1700
2017
Lamb, K.Lamb, K.Kimberlite intrusions, Kimberlitic as dispersal, diamond transport and diamond deposition: the potential role of Earth Systems Modelling in diamond exploration.11th. International Kimberlite Conference, PosterTechnologyEarth Systems Modelling
DS1990-0885
1990
Lamb, L.D.Kratschmer, W., Lamb, L.D., Fostiropoulos, K., Huffman, D.R.Solid C 60: a new form of carbonNature, Vol. 347, No. 6291, September 27, pp. 354-358GlobalExperimental petrology, Carbon- Solid C 60
DS201611-2109
2016
Lamb, M.P.Ganti, V., Von Hagke, C., Scherler, D., Lamb, M.P., Fischer, W.W., Avouac, J-P.Time scale bias in erosion rates of glaciated landscapes.Science Advances, Vol. 2, 10, 3p.GlobalGlaciology

Abstract: Deciphering erosion rates over geologic time is fundamental for understanding the interplay between climate, tectonic, and erosional processes. Existing techniques integrate erosion over different time scales, and direct comparison of such rates is routinely done in earth science. On the basis of a global compilation, we show that erosion rate estimates in glaciated landscapes may be affected by a systematic averaging bias that produces higher estimated erosion rates toward the present, which do not reflect straightforward changes in erosion rates through time. This trend can result from a heavy-tailed distribution of erosional hiatuses (that is, time periods where no or relatively slow erosion occurs). We argue that such a distribution can result from the intermittency of erosional processes in glaciated landscapes that are tightly coupled to climate variability from decadal to millennial time scales. In contrast, we find no evidence for a time scale bias in spatially averaged erosion rates of landscapes dominated by river incision. We discuss the implications of our findings in the context of the proposed coupling between climate and tectonics, and interpreting erosion rate estimates with different averaging time scales through geologic time.
DS1993-0685
1993
Lamb, S.Hoke, L., Lamb, S., Entenmann, J.Volcanic rocks from the Bolivian Altiplano: insights into crustalstructure, contamination, and magma genesis: comment and replyGeology, Vol. 21, No. 12, December pp. 1147-1149BoliviaTectonics, Magma
DS1993-0871
1993
Lamb, S.Lamb, S.Going with the flow...tectonicsNature, Vol. 362, No. 6418, March 25, pp. 294-295MantleTectonics, Brittle crust
DS1993-0872
1993
Lamb, S.Lamb, S.Tectonics... going with the flowNature, Vol. 362, No. 6418, March 25, pp. 294-295MantleTectonics, Continental lithosphere, plate boundary
DS1995-0935
1995
Lamb, S.Kennan, L., Lamb, S., Rundle, C.Potassium-Argon dates from the Altiplano and Cordillera oriental of Bolivia: implications for Cenozoic stratigraphyJournal of South American Earth Sciences, Vol. 8, No. 2, pp. 163-186BoliviaStratigraphy, Geochronology
DS1997-0646
1997
Lamb, S.Lamb, S., Hoke, L.Origin of the high pressurelateau in the Central Andes, Bolivia, South AmericaTectonics, Vol. 16, No. 4, August pp. 623-49BoliviaBolivian Altiplano, chronostratigraphy, tectonics, Structure, Tambo Tambilla, deformation, crustal
DS2000-0417
2000
Lamb, S.Hoke, L., Lamb, S., Poreda, R.J.Southern limit of mantle derived geothermal helium emissions in Tibet: implications for lithospheric ...Earth and Planetary Science Letters, Vol. 180, No. 3-4, pp.297-308.Tibet, MantleGeothermometry
DS2002-0913
2002
Lamb, S.Lamb, S.Is it all in the crust?Nature, No. 6912, Nov. 14, p. 130.MantleGeochemistry
DS200612-0760
2006
Lamb, S.Lamb, S.Shear stresses on megathrusts: implications for mountain building behind subduction zones.Journal of Geophysical Research, Vol. 111, B07401, 24p.South America, ChileSubduction zone - not specific to diamonds
DS201708-1574
2017
Lamb, S.Lamb, S., Moore, J.D., Smith, E., Stern, T.Episodic kinematics in continental rifts modulated by changes in mantle melt fraction.Nature, Vol. 547, 7661, pp. 84-88.Mantlemelting

Abstract: Oceanic crust is created by the extraction of molten rock from underlying mantle at the seafloor ‘spreading centres’ found between diverging tectonic plates. Modelling studies have suggested that mantle melting can occur through decompression as the mantle flows upwards beneath spreading centres, but direct observation of this process is difficult beneath the oceans. Continental rifts, however—which are also associated with mantle melt production—are amenable to detailed measurements of their short-term kinematics using geodetic techniques. Here we show that such data can provide evidence for an upwelling mantle flow, as well as information on the dimensions and timescale of mantle melting. For North Island, New Zealand, around ten years of campaign and continuous GPS measurements in the continental rift system known as the Taupo volcanic zone reveal that it is extending at a rate of 6-15?millimetres per year. However, a roughly 70-kilometre-long segment of the rift axis is associated with strong horizontal contraction and rapid subsidence, and is flanked by regions of extension and uplift. These features fit a simple model that involves flexure of an elastic upper crust, which is pulled downwards or pushed upwards along the rift axis by a driving force located at a depth greater than 15?kilometres. We propose that flexure is caused by melt-induced episodic changes in the vertical flow forces that are generated by upwelling mantle beneath the rift axis, triggering a transient lower-crustal flow. A drop in the melt fraction owing to melt extraction raises the mantle flow viscosity and drives subsidence, whereas melt accumulation reduces viscosity and allows uplift—processes that are also likely to occur in oceanic spreading centres.
DS202007-1181
2020
Lamb, S.Stern, T., Lamb, S., Moore, J.D.P., Okaya, D., Hichmuth, K.High mantle seismic P-wave speeds as a signature for gravitational spreading of superplumes. Science Adavances, Vol. 6, eaba7118 May 27, 9p. PdfAsia, Javageophysics -seismic

Abstract: New passive- and active-source seismic experiments reveal unusually high mantle P-wave speeds that extend beneath the remnants of the world’s largest known large igneous province, making up the 120-million-year-old Ontong-Java-Manihiki-Hikurangi Plateau. Sub-Moho Pn phases of ~8.8 ± 0.2 km/s are resolved with negligible azimuthal seismic anisotropy, but with strong radial anisotropy (~10%), characteristic of aggregates of olivine with an AG crystallographic fabric. These seismic results are the first in situ evidence for this fabric in the upper mantle. We show that its presence can be explained by isotropic horizontal dilation and vertical flattening due to late-stage gravitational collapse and spreading in the top 10 to 20 km of a depleted, mushroom-shaped, superplume head on a horizontal length scale of 1000 km or more. This way, it provides a seismic tool to track plumes long after the thermal effects have ceased.
DS1995-2040
1995
Lamb, S.H.Watts, A.B., Lamb, S.H., Fairhead, J.D.Lithospheric flexing and bending of the central AndesEarth and Planetary Science Letters, Vol. 134 No. 1-2, Aug 15, pp. 9-22AndesTectonics
DS1997-0581
1997
Lamb, S.H.Kennan, L., Lamb, S.H., Hoke, L.High altitude paleosurfaces in the Bolivian Andes: evidence for late Cenozoic surface upliftWiddowson, M. Paleosurfaces, Geological Society of London, No. 120, pp. 307-323BoliviaCentral Andes, Tectonics
DS200412-1081
2004
Lamb, W.Lamb, W.Mineral characterization to metallurgical design.PDAC 2004, 1p. abtract.TechnologyMining
DS200512-0597
2005
Lamb, W.Lamb, W.Parameters affecting dense medium process efficiency.CIM Mining Rocks April 24-27th. Toronto Annual Meeting, Paper# 1750 AbstractNews item - mineral processing
DS201609-1709
2010
Lamb, W.Campbell, J.A.H., Lamb, W., Clarke, J., Petersen, K.The development of AK6.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 20p.Africa, BotswanaDeposit - AK6
DS200912-0423
2009
Lamb, W.M.Lamb, W.M., Popp, R.K.Amphibole equilibration temperatures in mantle rocks: determining values of mantle alpha H2O and implications for mantle H2O contents.American Mineralogist, Vol. 94, 1, pp. 41-52.MantleWater
DS201904-0748
2019
Lamb, W.M.Hunt, L.E., Lamb, W.M.Application of mineral equilibria to estimate fugacities of H2O, H2, and O2 in mantle xenoliths from the southwestern U.S.A.American Mineralogist, Vol. 104, pp. 333-347.United Statesxenoliths

Abstract: Small amounts of H2O, on the order of tens to hundreds of parts per million, can significantly influence the physical properties of mantle rocks. Determining the H2O contents of nominally anhydrous minerals (NAMs) is one relatively common technique that has been applied to estimate mantle H2O contents. However, for many mantle NAMs, the relation between H2O activity and H2O content is not well known. Furthermore, certain mantle minerals may be prone to H2O loss during emplacement on Earth’s surface. The goal of this study is to apply mineral equilibria to estimate values of aH2O in rocks that originated below the Moho. The chemical compositions of olivine + orthopyroxene + clinopyroxene + amphibole + spinel ± garnet were used to estimate values of temperature (T), pressure (P), aH2O, hydrogen fugacity (fH2), and oxygen fugacity (fO2) in 11 amphibole-bearing mantle xenoliths from the southwestern U.S.A. Application of amphibole dehydration equilibria yields values of aH2O ranging from 0.05 to 0.26 for these 11 samples and the compositions of coexisting spinel + olivine + orthopyroxene yield ?logfO2 (FMQ) of -1 to +0.6. For nine of the samples, values of fH2 were estimated using amphibole dehydrogenation equilibria, and these values of fH2 ranged from 6 to 91 bars. Values of fH2 and fO2 were combined, using the relation 2H2O = 2H2 + O2, to estimate a second value of aH2O that ranged from 0.01 to 0.57 for these nine samples. Values of aH2O, estimated using these two methods on the same sample, generally agree to within 0.05. This agreement indicates that the amphibole in these samples has experienced little or no retrograde H-loss and that amphibole equilibria yields robust estimates of aH2O that, in these xenoliths, are generally <0.3, and are often 0.1 or less.
DS201212-0394
2012
Lambart, S.Lambart, S., Laporte, D., Provost, A., Schinao, P.Fate of pyroxenite derived melts in the periodotitic mantle: thermodynamic and experimental constraints.Journal of Petrology, Vol 53, 3, pp. 451-476.MantlePeridotite
DS201412-0498
2014
Lambart, S.Laporte, D., Lambart, S., Schiano, P., Ottolini, L.Experimental derivation of nepheline syenite and phonolite liquids by partial melting of upper mantle peridotites.Earth and Planetary Science Letters, Vol. 404, pp. 319-331.MantleMelting
DS201907-1557
2018
Lambart, S.Lambart, S., Koorneef, J., Millet, M-A., Davies, G.R., Cook, M., Lissenberg, J.Mantle heterogeneity revealed in the Lower Oceanic crust.American Geophysical Union, Fall Meeting. , V23A-05 1p.Mantlegeophysics

Abstract: Variations in radiogenic isotopes in mid-ocean ridge basalts (MORB) are interpreted to reflect the presence of enriched and depleted mantle components in their source regions and have been used to infer the abundance and time scales of crustal recycling. However, MORB are homogenized via magma mixing prior to eruption and may not capture the full heterogeneity of melts generated in their upper mantle source. Here we show that primitive cumulate minerals, formed by crystallization of mantle melts in the lower crust, retain the signature of the recycled material. We performed high spatial resolution Nd and Sr isotopic analyses on clinopyroxene and plagioclase of gabbroic cumulates from the Atlantis massif, located on a depleted ridge segment on the northern Mid-Atlantic Ridge, and compared these data with whole rock isotopic compositions of diabase and microgabbros collected on the same core, associated basalts flows, and MORB data from the literature. We find that cumulate minerals: (1) are significantly more isotopically heterogeneous than the associated diabase and lavas, exceeding the range of 143Nd/144Nd in MORB by a factor of seven; and (2) contain the full Nd isotopic heterogeneity of all of North Atlantic MORB. Furthermore, we find that isotopic heterogeneity occurs down to the sample scale, with plagioclase and clinopyroxene from individual samples commonly not in isotopic equilibrium. We further demonstrate that the MORB and cumulate mineral data can be reconciled with constant high magnitude, small length scale heterogeneity through the North Atlantic upper mantle, with limited magma mixing in the mantle and extensive mixing in the oceanic crust.The isotopic heterogeneity revealed in the lower oceanic crust provides strong evidence that MORB is not an accurate representation of the heterogeneity of its mantle source. Hence, the true isotopic variation of the upper mantle requires rigorous further examination, and models of convective thinning and stretching and melt migration must be re-evaluated to account for greater local variation.
DS1989-0525
1989
Lambeck, K.Goleby, B.R., Shaw, R.D., Wright, C., Kennett, B.L.N., Lambeck, K.Geophysical evidence for thick skinned crustal deformation incentralAustraliaNature, Vol. 337, No. 6205, January 26, pp. 325-330AustraliaGeophysics, Tectonics
DS1991-1562
1991
Lambeck, K.Shaw, R.D., Etheridge, M.A., Lambeck, K.Development of the Late Proterozoic to mid-Paleozoic intracratonic Amadeus Basin in central Australia: a key to understanding tectonic forces in plateinteriorsTectonics, Vol. 10, No. 4, August pp. 688-721AustraliaTectonics, Basin -Amadeus
DS1996-0803
1996
Lambeck, K.Lambeck, K., Smither, C.Shoreline evolution over the Northwest Shelf Australia for the past 20, 000years.Australia Nat. University of Diamond Workshop July 29, 30., 1/8p. brief.AustraliaGeomorphology, Sea level
DS2000-0474
2000
Lambeck, K.Kaufmann, G., Lambeck, K.Mantle dynamics, Post glacial rebound and radial viscosity profilePhysical Earth and Planetary Interiors, Vol. 121, No. 3-4, pp. 301-24.MantleGeodynamics, Geomorphology - glacial
DS201212-0823
2012
Lambeck, K.Zhao, S., Lambeck, K., Lidberg, M.Lithosphere thickness and mantle viscosity inverted from GPS - derived deformation rates in Fennoscandia.Geophysical Journal International, Vol. 190, 1, pp. 278-292.Europe, Finland, SwedenGeophysics - seismics
DS1991-1756
1991
Lambert, A.Tushingham, A.M., Lambert, A., Liard, J.O., Peltier, W.R.Secular gravity changes: measurements and predictions for selected CanadiansitesCanadian Journal of Earth Sciences, Vol. 28, No. 4, April pp. 557-560CanadaGeophysics -gravity, General
DS201612-2343
2016
Lambert, C.W.Thomas, R.J., Macey, P.H., Spencer, C., Dhansay, T., Diener, J.F.A., Lambert, C.W., Frei, D., Nguno, A.The Sperrgebeit Domain, Aurus Mountains, SW Namibia: a ~2020-850 Ma window within the Pan-African Gariep Orogen.Precambrian Research, Vol. 286, pp. 35-58.Africa, NamibiaGeochronology
DS1999-0261
1999
Lambert, D.Graham, S., Lambert, D., Shee, S., Smith, C.B., ReevesRe Os isotopic evidence for Archean lithospheric mantle beneath the Kimberley Block, Western Australia.Geology, Vol. 27, No. 5, May pp. 431-34.AustraliaGeochronology, Deposit - Argyle, Seppelt
DS1991-0949
1991
Lambert, D.D.Lambert, D.D., Shirey, S.B., Carlson, R.W., Weaver, B.L., GilbertRhenium- Osmium (Re-Os) and samarium-neodymium (Sm-Nd) isotopic systematics of lamproites and basalts from theEos Transactions, Vol. 72, No. 44, October 29, abstract p. 543Arkansas, MidcontinentLamproites, Geochemistry, geochronology
DS1993-0215
1993
Lambert, D.D.Carlson, R.W., Esperanca, S., Lambert, D.D., Svisero, D.P.The electromagnetic-I component in the South Atlantic: clues to the origin from isotope and trace element dat a for Brazilian kimberlites.American Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 633.BrazilGeochronology, Kimberlite
DS1993-0421
1993
Lambert, D.D.Esperanca, S., Carlson, R.W., Lambert, D.D., Svisero, D.P.The petrology and geochemistry of deep crustal granulite xenoliths in an ultrapotassic host, Minas Gerais State, Brasil.The Xenolith window into the lower crust, abstract volume and workshop, p. 8.BrazilUltrapotassic rocks
DS1994-0974
1994
Lambert, D.D.Lambert, D.D., Shirey, S.B., Bergman, S.C.Re Os and Sm neodymium isotope geochemistry of the Prairie Creek lamproites:evidence subduction related mantle.Geological Society of Australia Abstracts, No. 37, p. 231-232.ArkansasLamproites, Geochemistry
DS1995-1047
1995
Lambert, D.D.Lambert, D.D., Shirey, S.B., Bergman, S.C.Proterozoic lithospheric mantle source for the Prairie Creek lamproites:Rhenium- Osmium (Re-Os) and samarium-neodymium (Sm-Nd) isotopic evidence.Geology, Vol. 23, No. 3, March pp. 273-276.ArkansasGeochronology, Deposit -Prairie Creek
DS1996-0463
1996
Lambert, D.D.Foster, J.G., Lambert, D.D., Maas, R.Rhenium- Osmium (Re-Os) isotopic evidence for genesis of Archean nickel ores from uncontaminated komatiitesNature, Vol. 382, No. 6593, Aug. 22, pp. 703-705AustraliaNickel, komatiites, Geochronology
DS1996-0559
1996
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R., Hamilton, R., FosterAlkaline ultramafic rocks as probes of lithospheric mantle enrichment events in the eastern Yilgarn craton.Australia Nat. University of Diamond Workshop July 29, 30. abstract, 1p.AustraliaCraton, Alkaline rocks, geochronology
DS1996-0911
1996
Lambert, D.D.McBride, J.S., Lambert, D.D., Greig, A., Nicholls, I.A.Multistage evolution of Australian subcontinental mantle: Rhenium- Osmium (Re-Os) isotopic constraints from Victorian...Geology, Vol. 24, No. 7, July pp. 631-634.Australia, VictoriaMantle xenoliths, Geochronology
DS1997-0436
1997
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R., Hamilton, R.ReOs and SmNd evidence for Archean lithosphere mantle modification byorogenesis, Norseman, Western AustraliaGeological Society of Australia Abstracts, No. 44, p. 35. 1p.Australia, Western AustraliaGeochronology, picroilmentites, melnoite, Diamond exploration
DS1998-0529
1998
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R., Smith, HamiltonRe Os and Sm neodymium isotope systematics of alkaline ultramafic rocks, xenoliths and macrocrysts...7th International Kimberlite Conference Abstract, pp. 262-4.AustraliaAlkaline rocks, Yilgarn Craton, Earaheedy Basin area
DS1998-0530
1998
Lambert, D.D.Graham, S., Lambert, D.D., Smith, C.B., Shee, ReevesRhenium- Osmium (Re-Os) isotope systematics of oxide xenocrysts and peridotite xenoliths From the kimberlites - Argyle7th International Kimberlite Conference Abstract, pp. 265-7.AustraliaMantle - lithosphere, lamproite, Deposit - Argyle
DS1998-0826
1998
Lambert, D.D.Lambert, D.D., Alard, O., Costa, S., Frick, BodinierEvidence for interaction of Proterozoic (2 Ga) sub-continental mantle wit han enriched mantle plume...Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 848-9.FranceMelt depletion, peridotite xenoliths, Franch Massif Central
DS2001-0743
2001
Lambert, D.D.McBride, J.S., Lambert, D.D., Nicholls, I.A., Price, R.Osmium isotopic evidence for crust mantle interaction in the genesis of continental intraplate basalts ...Journal of Petrology, Vol. 42, No. 6, pp. 1197-1218.Australia, southeastNewer Volcanic Province, Geochronology
DS2002-0606
2002
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R., Pearson, N.J.Juvenile lithospheric mantle enrichment and the formation of alkaline ultramafic magmaChemical Geology, Vol. 186, No. 2-4, pp. 215-33.Australia, westernMelnoites, Geochronology
DS2003-0492
2003
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R.Geochemical and isotopic evidence of a kimberlite - melnoite - carbonatite genetic link8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractAustraliaKimberlite petrogenesis, Geochronology, Leonora alkalic province
DS2003-0493
2003
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R., Pearson, N.J.Erratum to juvenile lithospheric mantle enrichment and the formation of alkalineChemical Geology, Vol. Sept. 15, p.. 361. Original Vol. 186, pp. 215-233.AustraliaMelnoites, Geochronology
DS200412-0707
2003
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R.Geochemical and isotopic evidence of a kimberlite - melnoite - carbonatite genetic link.8 IKC Program, Session 7, AbstractAustraliaKimberlite petrogenesis Geochronology, Leonora alkalic province
DS200412-0708
2003
Lambert, D.D.Graham, S., Lambert, D.D., Shee, S.R., Pearson, N.J.Erratum to juvenile lithospheric mantle enrichment and the formation of alkaline ultramafic magma sources: Re Os Lu Hf and Sm NdChemical Geology, Vol. Sept. 15, p.. 361. Original Vol. 186, pp. 215-233.AustraliaMelnoites, geochronology
DS1997-0305
1997
Lambert, I.East, J., Lambert, I., Wood, P., Veitch, S.Recent trends in access to Australian mineral resourcesAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 4, June pp. 84-88AustraliaBrief overview, Resources, discoveries, economics
DS2001-0650
2001
Lambert, I.B.Lambert, I.B.Mining and sustainable development: considerations for minerals supplyNatural Res. Forum, Vol. 25, No. 4, pp. 275-84.GlobalLegal - economics
DS1989-0845
1989
Lambert, M.B.Lambert, M.B., Ernst, R.E.Mafic dyke swarms of the Cameron and Beaulieur River volcanic belts, SlaveProvince, N.W.T.Geological Society of Canada (GSC) Forum 1989, P. 16 abstractNorthwest TerritoriesDykes
DS1991-0253
1991
Lambert, R. St.J.Chamberlain, V.E., Lambert, R. St.J., McKerrow, W.S.Mesozoic sedimentation rates in the Western Canada basin as indicators Of the time and place of tectonic activityBasin Research, Vol. 2, No. 3, September pp. 189-202Western Canada, AlbertaTectonics, Peace River Arch, Basin
DS1987-0393
1987
Lambert, R.St. J.Lambert, R.St. J.Mid-Cretaceous alkaline igneous rocks in the southern Canadian Rockies And related areasEos, Vol. 68, No. 44, November 3, p. 1517. Abstract onlyBritish ColumbiaBlank
DS1986-0130
1986
Lambert, R.St.J.Cavell, P.A., Baadsgaard, H., Lambert, R.St.J.Samarium-Neodymium, Rubidium-Strontium, and Uranium-Lead systematics of the Big Spruce Lake alkaline carbonatiteGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 53-54. (abstract.)OntarioFoyalite, ijolite, geochronology, Carbonatite
DS201906-1312
2019
Lambert, S.Lambert, S., Koornneef, J.M., Millet, M-A., Davies, G.R., Cook, M., Lissenberg, C.J.Highly heterogeneous depleted mantle recorded in the lower oceanic crust. ( MAR)Nature Geoscience, https://doi.org/10.1038/s41561-019-0368-9 8p.Mantleplate tectonics

Abstract: The Earth’s mantle is heterogeneous as a result of early planetary differentiation and subsequent crustal recycling during plate tectonics. Radiogenic isotope signatures of mid-ocean ridge basalts have been used for decades to map mantle composition, defining the depleted mantle endmember. These lavas, however, homogenize via magma mixing and may not capture the full chemical variability of their mantle source. Here, we show that the depleted mantle is significantly more heterogeneous than previously inferred from the compositions of lavas at the surface, extending to highly enriched compositions. We perform high-spatial-resolution isotopic analyses on clinopyroxene and plagioclase from lower crustal gabbros drilled on a depleted ridge segment of the northern Mid-Atlantic Ridge. These primitive cumulate minerals record nearly the full heterogeneity observed along the northern Mid-Atlantic Ridge, including hotspots. Our results demonstrate that substantial mantle heterogeneity is concealed in the lower oceanic crust and that melts derived from distinct mantle components can be delivered to the lower crust on a centimetre scale. These findings provide a starting point for re-evaluation of models of plate recycling, mantle convection and melt transport in the mantle and the crust.
DS202007-1185
2020
Lambert, S.Xu, R., Liu, Y., Lambert, S.Melting of a hydrous peridotite mantle source under the Emeishan large igneous province.Earth Science Reviews, in press available 30p. PdfChinapicrites

Abstract: Large igneous provinces on Earth result from anomalously enormous volcanic eruptions at high melt production rates. These eruptions are often linked to catastrophic events such as mass extinctions, global climate changes, or continental break-up. Decoding their petrogenesis is therefore of great importance for our comprehensive understanding of the evolution and geodynamics of our planet. The ~260 Ma Emeishan large igneous province is an important geological feature of SW China with world-class ore deposits and is also suggested to be linked with the Capitanian mass extinction. However, fundamental aspects of the genesis of Emeishan province's most primitive lavas (picrites), such as the source lithology (pyroxenite or peridotite), the origin of compositional variations of olivines and the melting temperature and pressure conditions, remain poorly constrained. Here, we compile information on melt inclusion and host olivine, and whole-rock compositions from the ELIP picrites and show that these data are consistent with decompression melting of a relatively homogeneous peridotitic mantle plume, with a potential temperature higher than 1560 °C. The compositional variability of the olivines and picrites can be explained by varying the equilibrium depth of primary magma segregation and does not require the contribution of a pyroxenite component as previously suggested. Our results favor a scenario for the origin of the Emeishan large igneous province in which the decompression melting during upwelling of a hot hydrous and oxidized mantle plume is accompanied by catastrophic lithospheric thinning. In combination with the now extensive multi-element geochemical data, our findings provide a starting point for re-evaluation of the petrogenesis models for large igneous provinces.
DS1989-0846
1989
Lambiase, J.J.Lambiase, J.J.The framweork of African rifting during the PhanerozoicJournal of African Earth Sciences, Vol. 8, No. 2/3/4, pp. 183-190AfricaTectonics, Rifting -Phanerozoic
DS1993-0873
1993
Lambrecht, W.R.Lambrecht, W.R., Lee, C.H., Segall, B., Angus, J.C., Sunkara, M.Diamond nucleation by hydrogenation of the edges of graphitic precursorsNature, Vol. 364, August 12, pp. 607-610.GlobalDiamond morphology
DS1993-0874
1993
Lambrect, W.R.L.Lambrect, W.R.L., Lee, C.H., Segall, B., Angus, J.C., Li, Z.Diamond nucleation by hydrogenation of the edges of graphitic precursorsNature, Vol. 364, No. 6438, August 12, pp. 607-610GlobalDiamond morphology, Graphite
DS1995-1048
1995
Lambrinos, D.Lambrinos, D.Taxation and accounting issues relating to mining projects in RussiaWorld Mining Congress, Institute International Research held May, 26pRussiaEconomics -investment
DS201112-0566
2011
Lamcaster, P.J.Lamcaster, P.J., Storey, C.D., Hawkesworth, C.J., Dhuime, B.Understanding the roles of crustal growth and preservation in the detrital zircon record.Earth and Planetary Science Letters, In press, availableMantleGeochronology
DS200812-1045
2008
Lamenetsky, V.S.Sharygin, V.V., Lamenetsky, V.S., Kamenetsky, M.B.Potassium sulfides in kimberlite hosted chloride nyereite and chloride clasts of the Udachnaya East pipe, Yakutia, Russia.Canadian Mineralogist, Vol. 46, 4, August pp.Russia, YakutiaDeposit - Udachnaya
DS1989-0847
1989
Lameyre, J.Lameyre, J., Black, R., Giret, A.Le magmatism alcalin: donnees geologiques sur quelques provinces oceaniques et continentales.(in French)Geological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A49. (abstract.)West Africa, NigeriaAlkaline rocks
DS1999-0211
1999
Lamge R.A.Feldstein, S.N., Lamge R.A.Pliocene potassic magmas from the Kings River Basin, Sierra Nevada:evidence for melting subduction mantleJournal of Petrology, Vol. 40, No. 8, Aug. pp. 1301-20.CaliforniaTectonics - subduction
DS1991-1087
1991
Laming, D.McCall, G., Laming, D., Scott, S.GeohazradsChapman and Hall, 236p. approx. $ 40.00 United StatesGlobalBook -ad, Geohazards
DS1988-0396
1988
Lammer, A.Lammer, A.Mechanical properties of polycrystalline diamondsMater. Sci. Technol, Vol. 4, No. 11, pp. 949-955GlobalDiamond morphology
DS1950-0408
1958
Lamont, G.T.Lamont, G.T.Report on the Prospecting of the Tuli Block, Bechuana land Protectorate.De Beers Prospecting (rhodesia) Ltd., (UNPUBL.)BotswanaDiamond Prospecting
DS1950-0485
1959
Lamont, G.T.Lamont, G.T.Report on the Prospecting of the Gaberone Block, Bechuana land Protectorate.De Beers Prospecting (rhodesia) Ltd., (UNPUBL.)BotswanaDiamond Prospecting
DS1970-0119
1970
Lamont, G.T.Lamont, G.T.Prospecting MethodsIn: Diamonds, Editor Bruton, E., P. 119.South AfricaProspecting
DS201812-2850
2018
Lamontagne, M.McPeak, S., Samson, C., Lamontagne, M., Elliott, B.Application of passive seismic methodologies to the determination of overburden thickness.2018 Yellowknife Geoscience Forum , p. 111-112. abstractCanada, Northwest Territoriesgeophysics - seismics

Abstract: Diamond mining is central to the economic development of the Canadian North. Innovative methods are needed to identify new prospective targets, as many of them are hidden beneath a thick overburden of glacial sediments. Passive seismics is an emerging method used to map the thickness of near-surface geological layers. Vibrations from distant earthquakes are used as a source of signal and data is processed to estimate the depth of the interface between the overburden and the underlying bedrock. In July 2018, four Tromino seismographs were taken to a study site located approximately ten minutes driving north of Yellowknife. A total of 146 Tromino measurements and associated GPS elevation measurements were taken at 6 m intervals along a dirt road. Elevation measurements were averaged over the course of four days and the survey line was approximately 740 m long. Results indicated that depth to bedrock decreases near outcrops and increases in valleys however; another geophysical dataset is needed to validate the passive seismic data.
DS1996-0742
1996
Lamontagne, Y.King, A., Fullagar, P., Lamontagne, Y.Borehole geophysics in exploration, development and productionProspectors and Developers Association of Canada (PDAC) Short Course, pp. 239-252CanadaGeophysics -borehole, drillhole, Short course -Exploration technology
DS1997-0647
1997
LaMoreaux, P.E.LaMoreaux, P.E., Powell, W.J., LeGrand, H.E.Environmental and legal aspects of karst areasEnvironmental Geology, Vol. 29, No. 1-2, Jan. 1, pp. 23-36GlobalEnvironment, Karst
DS1995-1049
1995
Lamorey, G.Lamorey, G., Jacobson, E.Estimation of semivariogram parameters and evaluation of the effects ofdat a sparcityMathematical Geology, Vol. 27, No. 3, pp. 327-358GlobalGeostatistics, Jackknife kriging
DS1970-0461
1972
Lamorre, B.Alt, D., Hyndman, D.W., Ferguson, J.A., Lamorre, B.Pleistocene Maar Craters Near Drummond, MontanaNorthwest Geology, Vol. 1, PP. 33-37.United States, Montana, Rocky MountainsDiatreme
DS1993-0948
1993
LamotheMachado, 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
DS1990-1180
1990
Lamothe, D.Picard, C., Lamothe, D., Piboule, M., Oliver, R.Magmatic and geotectonic evolution of a Proterozoic oceanic basin system:the Cape Smith Thrust- Fold Belt.Precambrian Research, Vol. 47, pp. 223-249.Quebec, Labrador, New QuebecTectonics, Structure
DS1993-0875
1993
Lamothe, D.Lamothe, D., Dion, D-J., Choiniere, J., Rivard, P.Localisation d'anomalies magnetiques circulaires entre le 56 et 58 parallel Territoire du Nouveau Quebec.(in French)Quebec Department of Mines, MB 93-62, 23p.QuebecGeophysics -magnetics, Diatremes
DS1994-0975
1994
Lamothe, D.Lamothe, D., Dion, D.J., Choiniere, J., Rivard, P.Localisation d'anomalies magnetiques circulaires entre le 56eme et le 58emeparralele-Territoire du Nouveau Quebec. (in French)Quebec Department of Mines, No. MB 93-62, 24p. $ paper copy 6.00QuebecGeophysics -magnetics, Circular anomalies
DS1988-0397
1988
Lamothe, M.Lamothe, M.Dating till using thermoluminescenceQuaternary Science Reviews, Vol. 7, pp. 273-276. Database # 17543GlobalTill, Thermoluminescence
DS1988-0398
1988
Lamothe, M.Lamothe, M.Dating till using thermoluminesenceQuaternary Science Reviews, Vol. 7, pp. 273-276QuebecBecancoeur Till Wisconsinian or Illinoian
DS201312-0229
2013
Lamothe, M.Dube-Loubert, H., Roy, M., Allard, G., Lamothe, M., Veilette, J.J.Glacial and nonglacial events in the eastern James Bay lowlands, Canada.Canadian Journal of Earth Sciences, Vol. 50, 4, pp. 379-396.Canada, Ontario, QuebecGeomorphology
DS1989-0848
1989
Lampietti, F.Lampietti, F.Reports on the 28th. International Geological Congress meeting held Washington ,D.C. Part II. a commentary upon the Geological Workshop ondiamondsIndiaqua, No. 54, 1989/III, p. 19, 21GlobalConference -Diamond Workshop, Report on Diamond Worksho
DS1900-0427
1906
Lamplugh, G.W.Lamplugh, G.W.Note on the Occurrence of Dwyka Conglomerate in Kimberley Mines.British Association Advanced Science Report For 1905, Kimberley Meeting, P. 408.Africa, South AfricaDetailed Geology
DS200712-0592
2007
Lamprecht, G.H.Lamprecht, G.H., Human, H.G.C., Snyman, L.W.Detection of diamond in ore using pulsed laser Raman spectroscopy.International Journal of Mineral processing, Vol. 84, 1-4, October, pp. 262-273.TechnologySorting, laser excitation
DS200812-0629
2007
Lamprecht, G.H.Lamprecht, G.H., Human, H.G.C., Synman, L.W.Detection of diamond in ore using pulsed laser Raman Spectroscopy.International Journal of Mineral Processing, Vol. 84, pp. 262-273.TechnologySpectroscopy
DS200912-0424
2009
Lamprecht, G.H.Lamprecht, G.H., Human, H.G.C., Snyman, L.W.Diamond detection in ore using laser Raman spectrosopy: comparison between pulsed and continuous wave lasers as excitation source at 532 nm.Transactions of the Institution of Mining and Metallurgy, Vol. 118, 1, March pp. 60-62.TechnologyDiamond processing
DS2001-0651
2001
Lan, C.Y.Lan, C.Y., Chung, S.L., Lo, Lee, Wang, Li, Van ToanFirst evidence for Archean continental crust in northern Vietnam and its implications for crustal ...Geology, Vol. 29, No. 3, Mar. pp.219-22.GlobalTectonic evolution, Geochronology, Yangtze Craton
DS200612-0761
2006
Lan, C.Y.Lan, C.Y., Izuka,T., Usuki, T., Wang, K.L., Anh, T.T., Van lOng ,T., O'Reilly, S.Y.Petrology and geochemistry of peridotite xenoliths from Vietnam Indochin a block.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 2. abstract only.ChinaXenolith - geochemistry
DS1995-0830
1995
Lan, L.Hudleston, P.J., Lan, L.Rheological information from geological structuresPure and Applied Geophysics, Vol. 145, No. 3-4, Dec. 1, pp. 605-620.MantleGeodynamics
DS201112-0567
2011
Lan, T-G.Lan, T-G., Fan, H-R., Santosh, M., Hu, F-F., Yang, Y-H, Liu, Y.Geochemistry and Sr Nd Pb Hf isotopes of the Mesozoic Dadian alkaline intrusive complex in the Sulu orogenic belt, eastern China: implications for crust mantle interaction.Chemical Geology, Vol. 285, 1-4, pp. 97-114.ChinaAlkalic
DS201602-0217
2016
Lan, Y.Lan, Y., Liang, R., Lu, T.Identification of a CVD synthetic diamond with a tree ring growth pattern.Journal of Gemmology, Vol. 34, 8, pp. 702-710.TechnologySynthetics
DS201901-0043
2018
Lan, Y.Ke, J., Lu, T., Lan, Y., Song, Z., Tang, S., Zhang, J., Chen, H.Recent developments in detection and gemology in China, particularly for Chinese synthetic diamonds.Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 268.Chinasynthetics

Abstract: China is the world’s largest producer of HPHT-grown industrial diamonds. Its 2016 production of about 20 billion carats accounted for 98% of the global supply. Since the beginning of 2015, meleesized colorless HPHT synthetic diamonds have been tested at the National Gemstone Testing Center’s (NGTC) Shenzhen and Beijing laboratories in parcels submitted by different clients, which means that colorless HPHT synthetic diamonds have entered the Chinese jewelry market and may be mistaken for natural diamonds. CVD synthesis technology has grown rapidly in recent years. Large colorless and colored (blue, pink) CVD-grown diamonds have been entering the market, and a few have been fraudulently sold as natural diamonds. China has independently developed gem-grade HPHT synthetic diamond production technology since 2002, and can grow gem-grade type Ib, IIa, and IIb and high-nitrogen-content synthetic diamonds in volume, depending on market needs. Gemgrade type Ib, IIa, and IIb HPHT synthetic diamonds have been grown using the temperature gradient method, under a cubic press at high pressure (e.g., 5.4 GPa) and high temperature (1300-1600°C). Driven by a specific temperature gradient, the carbon source from high-purity graphite (>99.9%) located at the high-temperature zone can diffuse into the seed crystals in the cubic press, resulting in the crystallization of synthetic diamonds. Chinese production of melee-sized colorless to near-colorless HPHT synthetic diamonds accounts for about 90% of the global output. Gem-grade type IIa and IIb CVD synthetic diamonds are grown using the microwave plasma chemical vapor deposition (MPCVD) and direct current (DC) arc plasma methods. Faceted colorless CVD diamonds can be grown in sizes up to 6 ct by at least two Chinese companies (table 1). After testing and analyzing thousands of natural and synthetic diamonds collected directly from the Chinese companies, NGTC independently developed the GV5000, PL5000, DS5000, and ADD6000 instruments for rapidly screening and identifying the diamonds based on the gemological characteristics obtained. Besides HPHT and CVD synthetic diamonds, a thickly layered hybrid diamond consisting of both natural and CVD material was identified at the NGTC Beijing laboratory (figure 1). The identification features and properties of regrown CVD synthetic diamonds using natural type Ia diamond crystals as seeds will be reported. The current status and features of colored stones examined at NGTC laboratories, including several cases studies, will be discussed.
DS201312-0994
2013
Lan, Z-W.Ye, H-M., Li, X-H., Lan, Z-W.Geochemical and Sr-Nd-Hf-O-C isotopic constraints on the origin of the Neoproterozoic Qieganbulake ultramafic carbonatite complex from the Tarim block, northwest China.Lithos, Vol. 182, pp. 150-164.ChinaCarbonatite
DS2003-0771
2003
Lana, C.Lana, C., Gibson, R.L., Kisters, A.F., Reimold, W.U.Archean crustal structure of the Kaapvaal Craton, South Africa - evidence from theEarth and Planetary Science Letters, Vol. 206, 1-2, pp. 133-44.South AfricaTectonics
DS200412-1082
2004
Lana, C.Lana, C., Reimold, W.U., Gibson, R.L., Koeberl, C., Siegesmund, S.Nature of the Archean midcrust in the core of the Vredfort dome, Central Kaapvaal Craton, South Africa.Geochimica et Cosmochimica Acta, Vol. 68, 3, pp. 623-42.Africa, South AfricaCraton, not specific to diamonds
DS200612-0037
2006
Lana, C.Armstrong, R.A., Lana, C., Reimold, W.U., Gibson, R.L.Shrimp zircon age constraints on Mesoarchean crustal development in the Vredefort dome, central Kaapvaal Craton, South Africa.Geological Society of America, Special Paper 405, pp. 233-254.Africa, South AfricaGeochronology
DS201112-0959
2011
Lana, C.Silva, D., Lana, C., Stevens, G., Souza Filho, C.R.Effects of shock induced incongruent melting within Earth's crust: the case of biotite melting.Terra Nova, in press availableMantleMelting
DS1997-0648
1997
Lanardic, A.Lanardic, A.On the heat flow variation from Archean craton to Proterozoic mobilebelts.Journal of Geophysical Research, Vol. 102, No. B1, Jan. 10, pp. 709-746.GlobalCraton, Mobile belts
DS201803-0446
2017
Lanari, P.Engi, M., Lanari, P., Jokn, M.J.Significant ages - an introduction to petrochronology.Reviews in Mineralogy & Geochemistry, Vol. 83, Chap. 1, pp. 1-12.Technologygeochronology

Abstract: Question: Why "Petrochronology"? Why add another term to an already cluttered scientific lexicon? Answer: Because petrologists and geochronologists need a term that describes the unique, distinctive way in which they apply geochronology to the study of igneous and metamorphic processes. Other terms just won’t do.
DS201806-1222
2018
Lanari, P.Engi, M., Giuntoli, F., Lanari, P., Burn, M., Kunz, B., Bouvier, A.S.Pervasive eclogization due to brittle deformation and rehydration of subducted basement: effects on continental recycling?Geochemistry, Geophysics, Geosystems, Vol. 19, 3, pp. 865-881.Mantlesubduction

Abstract: The buoyancy of continental crust opposes its subduction to mantle depths, except where mineral reactions substantially increase rock density. Sluggish kinetics limit such densification, especially in dry rocks, unless deformation and hydrous fluids intervene. Here we document how hydrous fluids in the subduction channel invaded lower crustal granulites at 50-60 km depth through a dense network of probably seismically induced fractures. We combine analyses of textures and mineral composition with thermodynamic modeling to reconstruct repeated stages of interaction, with pulses of high-pressure (HP) fluid at 650-6708C, rehydrating the initially dry rocks to micaschists. SIMS oxygen isotopic data of quartz indicate fluids of crustal composition. HP growth rims in allanite and zircon show uniform U-Th-Pb ages of 65 Ma and indicate that hydration occurred during subduction, at eclogite facies conditions. Based on this case study in the Sesia Zone (Western Italian Alps), we conclude that continental crust, and in particular deep basement fragments, during subduction can behave as substantial fluid sinks, not sources. Density modeling indicates a bifurcation in continental recycling: Chiefly mafic crust, once it is eclogitized to >60%, are prone to end up in a subduction graveyard, such as is tomographically evident beneath the Alps at 550 km depth. By contrast, dominantly felsic HP fragments and mafic granulites remain positively buoyant and tend be incorporated into an orogen and be exhumed with it. Felsic and intermediate lithotypes remain positively buoyant even where deformation and fluid percolation allowed them to equilibrate at HP.
DS2001-0037
2001
Lanat, J-F.Annen, C., Lanat, J-F., Provost, A.The long term growth of volcanic edifices: numerical modelling of the roleof dike intrusion and lava flow..Journal of Volcan. Geotherm Res., Vol. 105, pp. 263-89.GlobalDyke intrusions - not specific to diamond
DS1970-0950
1974
Lancaster, I.N.Lancaster, I.N.Pans of the Southern KalahariBotswana Notes And Records, Vol. 6, PP. 157-169.BotswanaGeomorphology
DS1988-0163
1988
Lancaster, N.Deacon, J., Lancaster, N.Late Quaternary Paleoenvironments of southern AfricaOxford University of Press, 236p. APPROX. $65.00USSouth AfricaPaleogeography
DS2003-0161
2003
Lancaster, N.Bristow, C.S., Lancaster, N., Duller, G.A.Combining ground penetrating radar and optical dating to determine dune migration inGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p.300.NamibiaGPR, geomorphology
DS200412-0209
2003
lancaster, N.Bristow, C.S., lancaster, N.,Duller, G.A.Combining ground penetrating radar and optical dating to determine dune migration in Namibia.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p.300.Africa, NamibiaGPR, geomorphology
DS201112-0568
2011
Lancaster, P.J.Lancaster, P.J., Storey, C.D., Hawkesworth, C.J., Dhuime, B.Understanding the roles of crustal growth and preservation in the detrital zircon record.Earth and Planetary Science Letters, Vol. 305, 3-4, pp. 405-412.MantleGeochronology
DS201412-0496
2014
Lancaster, P.J.Lancaster, P.J., Dey, S., Storey, C.D., Mitra, A., Bhunia, R.K.Contrasting crustal evolution processes in the Dharwar craton: insights from detrial zircon U-Pb and Hf isotopes.Gondwana Research, in press availableIndiaCraton, geodynamics
DS1940-0121
1946
Lancsweert, P.Lancsweert, P.Belgian Congo Diamond MinesRoy. Col. Institute, Vol. 17, No. 2, P. 732.Democratic Republic of Congo, Central AfricaMining
DS1997-1098
1997
Land, B.A.Stapleton, J., Land, B.A.Metallic and industrial mineral assessment report, lamprophyres of Peace River District, ashes ...Alberta Geological Survey, MIN 19970006AlbertaExploration - assessment, TUL Petroleums Ltd.
DS1998-1403
1998
Land, P.Stapleton, M.J., Land, P.Metallic and industrial mineral assessment report on the West River diamond indicator geochemistryAlberta Geological Survey, MIN 19980014, pt.3.AlbertaExploration - assessment, Hawk Hills Magnetic Anomaly, TUL Petroleums
DS1999-0708
1999
Land, P.Stapleton, M.J., Land, P.Exploration of the West Peace River diamond indicator mineral trendAlberta Geological Survey, MIN 19990025AlbertaExploration - assessment, New Claymore Resources Ltd.
DS1999-0709
1999
Land, P.Stapleton, M.J., Land, P.Exploration of thew West Peace River diamond indicator mineral trendAlberta Geological Survey, MIN 19990025AlbertaExploration - assessment, New Claymore Resources Ltd.
DS1993-0876
1993
Landa, E.Landa, E., Thore, P., Reshef, M.Model based stack: a method for constructing an accurate zero-offsetsection for complex overburdensGeophysical Prospecting, Vol. 41, pp. 661-670GlobalGeophysics -experimental not practical, Overburden
DS1981-0088
1981
Landa, E.A.Bogdasarov, E.A., Landa, E.A., Markovskiy, A.A.Chemical Composition and Crystallization Conditions of Chrome Spinels of Volcanic Ultramafics and Other Rocks of the Mafic Ultramafic Series.International Geology Review, Vol. 23, No. 9, PP. 931-RussiaKimberlite, Spinels, Mineralogy
DS1983-0382
1983
Landa, E.A.Landa, E.A., Krashnova, N.I., Tarhovskaya, A.N., Shergina, Y.P.The distribution of rare earths and yttrium in apatite from alkali-ultrabasic and carbonatite intrusions and the origin ofapatitemineralizationGeochemistry International, Vol. 20, No. 1, pp. 77-87Russia, FennoscandiaCarbonatite, Rare Earth
DS1983-0383
1983
Landa, E.A.Landa, E.A., Lyapunov, S.M., Markovskiy, B.A.Characteristics of rare earth distribution in volcanicultrabasites.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 272, No. 2, pp. 462-464RussiaKamchatka Pen., Anabar Shield, Meymechite, Picrite, Rare Earth
DS1983-0384
1983
Landa, E.A.Landa, E.A., Murina, G.A, SHERAGINA, Yu.p., KRASNOVA, N.i.Isotopic Composition of Strontium in Apatite and Apatite Bearing Rocks of Carbonatite Complexes.Geochemistry International (Geokhimiya), Vol. 20, No. 3, PP. 214-216.RussiaRelated Rocks
DS1992-0092
1992
Landefeld, L.A.Barriga, F.J.A.S., Fyfe, W.S., Landefeld, L.A., Munha, J., RibeiroMantle eduction: tectonic fluidisation at depthEarth Science Reviews, Vol. 32, pp. 123-129MantleTectonic fluidization, Seismics
DS2001-0652
2001
Landen, L.S.Landen, L.S., Ramo, O.T.Silicic magmatism and Early Paleoproterozoic continental rifting, east FIn land and adjacent RussiaGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.81.abstract.Finland, RussiaMagmatism
DS2002-0778
2002
Landenberger, B.Jenkins, R.B., Landenberger, B., Collins, W.J.Late Paleozoic retreating and advancing subduction boundary in the New England fold belt, New South Wales.Australian Journal of Earth Sciences, Vol.49, No. 3, pp. 467-90.AustraliaSubduction
DS1930-0073
1931
Landes, K.K.Landes, K.K.A Paragenetic Classification of the Magnet Cove MineralsAmerican MINERALOGIST., Vol. 16, No. 8, PP. 313-326.United States, Gulf Coast, Arkansas, Hot Spring CountyMineralogy
DS1950-0114
1952
Landes, K.K.Oesterling, W.A. , Landes, K.K.Geologic and Economic Significance of the Huston Zinc Mine, salem Kentucky Fluorspar District.Economic Geology, Vol. 47, No. 3, PP. 316-338.GlobalKimberlite, Western Kentucky, Central States
DS1930-0141
1933
Landes, K.R.Landes, K.R., Ockepan, J.W.Origin of Domes in Lincoln and Mitchell Counties, KansasGeological Society of America (GSA) Bulletin., Vol. 44, No. 3, PP. 529-540.KansasKimberlite, Central States, Wilson, Woodson
DS201212-0781
2012
Landgrade, T.C.W.Williams, S.E., Muller, R.D., Landgrade, T.C.W., Whittaker, J.M.An open source software environment for visualizing and refining plate tectonic reconstructions using high resolution geological and geophysical dat a sets.Geology Today, Vol. 22, no. 4/5, pp. -9.TechnologyGplates
DS201212-0645
2012
Landgrebe, T.C.W.Shephard, G.E., Bunge, H-P., Schuberth, B.S.A., Muller, R.D., Talsma, A.S., Moder, C., Landgrebe, T.C.W.Testing absolute plate reference frames and the implications for the generation of geodynamic mantle heterogeneity stucture.Earth and Planetary Science Letters, Vol. 317-318, pp. 204-217.MantleGeodynamics
DS1992-0082
1992
Landi, P.Barberi, F., Bertagnini, A., Landi, P., Principe, C.A review on phreatic eruptions and their precursorsJournal of Volcanology and Geothermal Research, Vol. 52, pp. 231-246GlobalVolcanics, Phreatomagmatics
DS201112-0981
2010
Landim Dominguez, J.M.Soares Lima, E., Landim Dominguez, J.M.Analise de minerais pesados como ferramenta na avaliacao de possiveis depositos diamantiferos na platforma continental no sul da Bahia.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 62.South America, Brazil, BahiaPlacer diamonds
DS1975-0331
1976
Landis, G.P.Mansker, W.L., Brookins, D.G., Landis, G.P., et al.Post Devonian Distremes in Southeast Missouri, Investigation of the Avon Kimberlite and Some Emplacement Parameters.Eos, Vol. 57, No. 10, P. 761, (abstract.).GlobalKimberlite, Central States, Alnoite
DS1996-0804
1996
Landol, J.D.Landol, J.D., Foland, K.A.The formation of quartz syenite by crustal contamination at Mont Shefford and other MontregianCanadian Mineralogist, Vol. 34, pt. 2, April pp. 301-324.QuebecMetasomatism, Montregian Complexes
DS1994-0529
1994
Landoll, .J.D.Foland, K.A., Landoll, .J.D., Henderson, C.M.B.Some consequences of interaction between mantle magmas and crust in the formation of epizonal alkaline complexes.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.MantleAlkaline rocks
DS1994-0976
1994
Landoll, J.D.Landoll, J.D., Foland, K.A., Chen, J-F., Henderson, C.M.B.The role of crustal contamination in the formation of silica oversaturated rocks in the Montregian Hills province, Quebec.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. posterQuebecAlkaline rocks, Montregian Hills
DS1992-0843
1992
Landon, S.M.Kerr, S.D., Landon, S.M.Proterozoic Midcontinent rift system, an overviewGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A328MidcontinentGeophysics -gravity, Tectonics, rifting
DS200612-1169
2006
Landonio, M.Rolandi, V., Brajkovic, A., Adamo, I., Landonio, M.Diamonds from Udachnaya pipe, Yakutia. Their morphology, optical and Raman characteristics, FTIR and CL features.Australian Gemmologist, Vol. 22, no. 9 Jan-Mar, pp.RussiaDiamond morphology
DS201012-0422
2010
Landreth, J.O.Landreth, J.O., Dockweiler, P.J.Mountain Pass carbonatite project.International Workshop Geology of Rare Metals, held Nov9-10, Victoria BC, Open file 2010-10, extended abstract pp. 19-20.United States, CaliforniaCarbonatite
DS2002-0154
2002
Landrgebe, D.Biehl, L., Landrgebe, D.MultiSpec - a tool for multispectral hyper spectral image dat a analysesComputers and Geosciences, Vol. 28, 10, pp.1153-59.GlobalComputers - programs
DS201012-0423
2010
Landry, F.Landry, F., Denholm, E., Hanks, C.Fish habitat compensation and mining in the North. Ekati has two compensation programs.38th. Geoscience Forum Northwest Territories, Abstract p. 60.Canada, Northwest TerritoriesEkati
DS200812-0630
2008
Landuyt, W.Landuyt, W., Bercovici, D., Ricard, Y.Plate generation and two phase damage theory in a model of mantle convection.Geophysical Journal International, Vol. 174, 3, pp. 1065-1080.MantleConvection
DS201212-0536
2012
Landuyt, W.Paczkowski, K., Bercovici, D., Landuyt, W., Brandon, M.T.Drip instabilities of continental lithosphere: acceleration and entrainment by damage.Geophysical Journal International, in press availableMantleRheology
DS2001-0653
2001
Landwehr, D.Landwehr, D., Blundy, J., Chamorro-Perez, Hill, E., WoodU series disequilibration temperatures generated by partial melting of spinel lherzoliteEarth and Planetary Science Letters, Vol. 188, No. 3-4, pp. 329-48.MantleMelting, lherzolite
DS1989-0322
1989
Lane, A.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.
DS1992-0348
1992
Lane, D.E.Day, W.C., Lane, D.E.Strategic and critical minerals in the midcontinent regionUnited States Geological Survey (USGS) Bulletin, 1989 A-C, 42p. $ 3.00Midcontinentmineral resources, Economics
DS201609-1728
2010
Lane, G.R.Lane, G.R., Milovanovic, B., Bondi, E.Economic modelling and its application in strategic planning.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 14p.GlobalEconomics - strategic planning

Abstract: Mining executives often have a difficult task detennining what the strategic objective of the business should be as this can be impacted by the prevailing market conditions. In addition, they have no mechanism to quantitatively 'test' the impact of this strategic decision on the business and understand the underlying dynamics. During the commodities bull run of 2003 to 2008 the strategic objective may have been to grow the long term value of the business (NPV) tluough increased tonnage, acquisition and finding new reserves, which all came with an increasing fixed cost base. Now with the financial crisis upon us and the collapse of commodity prices and demand, executives have adjusted their strategies as 'cash is king' and short-tenn cash flow, in some instances at the expense of long terms value, is the order of the day. For many mining companies, mine closures, reductions in production and cost cutting exercisers are now the focus. In many instances, management do not have an ability to rapidly test different strategic alternatives to 'test' the impact on value, unit costs, reserves and profitability at the operational level and optimise the underlying trade-off variables. Economic modelling of the complete business value chain is a means of linking the operational 'reality ' and strategic choices, so that the full impact can be assessed. This paper describes some of the challenges facing mining executives and how economic modelling can be applied to make decision making more rigorous.
DS1994-1688
1994
Lane, L.SStephenson, R.A., Coflin, K.C., Lane, L.S, DietrichCrustal structure and tectonics of the southeast Beaufort Sea continentalmargin.Tectonics, Vol. 13, No. 2, Apr. pp. 389-400.Northwest Territories, Beaufort SeaTectonics - structure
DS2000-0149
2000
Lane, L.S.Cecile, M.P., Lane, L.S., Morrow, StockmalMajor basement controlled features of the Central Foreland north of Peace River Arch.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstractAlberta, Cordillera, British Columbia, Western CanadaTectonics, Basin - activity
DS1960-0164
1961
Lane, M.Lane, M.A Calabash of Diamonds: an African Treasure HuntLondon: Heinemann., 215P.South AfricaTravelogue, History, Kimberley
DS200612-1306
2005
Lane, R.Simandl, G.J., Ferbey, T., Levson, V.M., Robinson, N.D., Lane, R., Smith, R., Demchuk, Raudsepp, HickinKimberlite and diamond indicator minerals in northeast British Columbia, Canada - a reconnaissance survey.British Columbia Geological Survey, Geofile 2005-25, 25p.Canada, British ColumbiaGeochemistry, geochronology, Buffalo Head Terrane
DS1995-1050
1995
Lane-Serff, G.F.Lane-Serff, G.F.Partial recycling in hydrothermal plumes.. commentEarth and Planetary Science Letters, Vol. 132, pp. 233-234GlobalPlumes, Hot spots
DS1988-0371
1988
Lanev, V.S.Kozlovskiy, Ye.A., Guberman, D.M., Kazanskiy, V.I., Lanev, V.S.The ore potential of deep seated zones of ancient continental crust Based on dat a from the Kola Superdeep drillholeInternational Geology Review, Vol. 30, No. 7, July pp. 763-771. Database # 17694RussiaOre deposits, Genesis
DS200912-0757
2009
Lang, A.Thrasher, I.M., Mauz, B., Chiverrell, R.C., Lang, A.Luminescence dating of glaciofluvial deposits: a review.Earth Science Reviews, Vol. 97, pp. 145-158.TechnologyNot specific to diamonds
DS1960-0855
1967
Lang, A.R.Lang, A.R.Causes of Birefringence in DiamondNature., Vol. 213, No. 5073, PP. 248-251.GlobalDiamond Morphology
DS1970-0966
1974
Lang, A.R.Moore, A.M., Lang, A.R.Correlations between Habit, Ultraviolet Transparency and Birefringence Features in South African Microdiamonds.Diamond Research, 1974, PP. 16-15.South AfricaCrystallography, Micro-diamonds
DS1975-0321
1976
Lang, A.R.Lang, A.R., Woods, G.S.Finger Printing Diamonds by X Ray TopographyIndustrial Diamond Review., MARCH PP. 96-103.GlobalDiamond Morphology
DS1981-0001
1981
Lang, A.R.Adams, R.C.G., Bielicki, T.A., Lang, A.R.Correlation of Electrostatic Charging Patterns with Internal Structure in Diamonds.Journal of MATERIALS SCIENCE., Vol. 16, No. 9, PP. 2369-2380.GlobalDiamond Morphology
DS1982-0586
1982
Lang, A.R.Sumida, N., Lang, A.R.On Spike Diffuse Reflections in Electron Diffraction Patterns of Diamonds.Journal of APPL. CRYSTALLOGRAPHY, Vol. 15, No. 3, PP. 266-274.GlobalDiamond Crystallography
DS1983-0385
1983
Lang, A.R.Lang, A.R., Walmsley, J.C.Apatite Inclusions in Natural Diamond CoatPhysics And Chemistry of Metals, Vol. 9, No. 1, PP. 6-9.GlobalBlank
DS1985-0379
1985
Lang, A.R.Lang, A.R., Kowalski, G., Makepeace, A.P.Recording Diffuse X-ray Reflections with Continuous Synchroton Radiation - an Application to Type 1a Diamond.Phil. Magazine, SECT. A, Vol. 52, No. 1, JULY, PP. 1-L. (LETTER).GlobalMineralogy
DS1988-0677
1988
Lang, A.R.Sumida, N., Lang, A.R.On the measurement of population density and size of platelets in type 1Adiamond and its implications for platelet structure modelsProceedings of the Royal Society of London, Section A, Vol. 419, No. 1857, pp. 235-257GlobalDiamond morphology, Nitrogen
DS1991-0950
1991
Lang, A.R.Lang, A.R., Moore, M., Makepeace, A.P., Wierzchov, W.On the dilation of synthetic type 1B diamond by substitutional nitrogenimpurityPhil. Transactions Roy. A., Vol. A 337, No. 1648, Dec. 16, pp. 497-520GlobalDiamond synthesis, Nitrogen impurity
DS1992-1627
1992
Lang, A.R.Walmsley, J.C., Lang, A.R.On sub-micrometre inclusions in diamond coat: crystallography and composition of ankerites and related rhombohedral carbonates.Mineralogical Magazine, Vol. 56, December pp. 533-543.GlobalDiamond CVD., Inclusions in CVD.
DS1992-1628
1992
Lang, A.R.Walmsley, J.C., Lang, A.R.Oriented biotite inclusions in diamond coatMineralogical Magazine, Vol. 56, March pp. 108-111GlobalDiamond morphology, Natural diamonds, biotite
DS1993-0779
1993
Lang, A.R.Kaneka, K., Lang, A.R.Chlorine and optical microtopographic studies of Argyle diamondsIndustrial Diamond Review, # MX681, Vol. 53, No. 6, pp. 334-337.AustraliaDiamond morphology, Deposit -Argyle
DS1993-0877
1993
Lang, A.R.Lang, A.R.Topographic methods for studying defects in diamondsDiamond Relat, Vol. 2, No. 2-4, March 31, pp. 106-114GlobalDiamond inclusions
DS1994-0977
1994
Lang, A.R.Lang, A.R.Lattice parameter determinations in diamond: an overviewProperties and growth of diamond, G. Davies, pp. 106-110.GlobalDiamond, Properties of nitrogen in diamond
DS1994-0978
1994
Lang, A.R.Lang, A.R.Effect of nitrogen on the lattice parameter of diamondProperties and growth of diamond, G. Davies, pp. 111-115.GlobalDiamond, Properties of nitrogen in diamond
DS1994-0979
1994
Lang, A.R.Lang, A.R.Topographial studies of nitrogen in diamondProperties and growth of diamond, G. Davies, pp. 116-120.GlobalDiamond, Properties of nitrogen in diamond
DS1994-0980
1994
Lang, A.R.Lang, A.R.An unusual octahedral diamondMineralogical Magazine, Vol. 58, No. 392, Sept. 508-512.GlobalMineralogy, Diamond morphology
DS200812-0631
2007
Lang, A.R.Lang, A.R., Bulanova, G.P., Fisher, D., Fukert, S., Saruna, A.Defects in a mixed habit Yakutian diamond: studies by optical and cathodluminescence microscopy, infrared absorption, Raman Scattering and photoluminesence spectJournal of Crystal Growth, Vol. 309, 2, pp. 170-180.TechnologySpectroscopy
DS1989-0986
1989
Lang, H.R.McGuffie, B.A., Johnson, L.F., Alley, R.E., Lang, H.R.IGIS Computer aided photogeologic mapping with image processing, graphic sand CAD/CAM capabilitiesGeobyte, Vol. 4, No. 5, pp. 8, 10-14. Database #18194GlobalComputer, Program -IGIS
DS1994-0981
1994
Lang, H.R.Lang, H.R., Paylor, E.D.Spectral stratigraphy: remote sesning lithostratigraphic procedures for basin analysis, Central Wyoming examplesNonrenewable Resources, Vol. 3, No. 1, Spring, pp. 25-45WyomingRemote sensing, Stratigraphy
DS1990-0854
1990
Lang, J.Kogbe, C.A., Lang, J.Great African continental complexes. Special issue -major African continental Phanerozoic complexes and dynamics of sedimentationJournal of African Earth Sciences, Vol. 10, No. 1/2 pp. 1-400AfricaContinetal complexes, Sediments
DS1992-0230
1992
Lang, J.Cessier, C., Lang, J.La Formation glaciaire de la Mambere (Republique Centrafricaine):reconstitution paleogeographique et implications a l'echelle du Paleozoiqueafricain.(in French)Geologische Rundschau, (in French), Vol. 81, No. 3, pp. 769-789Central African RepublicGeomorphology, Glacial till
DS1995-1051
1995
Lang, J.R.Lang, J.R., Lueck, B., Mortensen, J.K., Russell, J.K.Triassic Jurassic silica undersaturated and silica saturated alkalic intrusions in Cordillera-arc magmaGeology, Vol. 23, No. 5, May pp. 451-454.British ColumbiaAlkalic intrusives, Arc magmatism, Quesnellia terrane, Stikinia terrane
DS1988-0399
1988
Lang, L.Lang, L.Are CAD and GIS evolving toward the same answer?Geobyte, Vol. 3, No. 4, November pp. 12-15. Database # 17519GlobalComputer, Program-CAD-GIS
DS2000-0963
2000
Lang, M.Ulrych, J., Pivec, E., Lang, M., Lloyd, F.E.Ijolite segregations in melilite nephelinite of Podhorni arch volcano, western Bohemia.Neues Jahr. Min. Abh., No. 175, No. 3, pp. 317-48.Europe, BohemiaOlivine nephelinite
DS1910-0198
1911
Lang, P.Lang, P.Discovery of Diamonds in CanadaU.s. Monthly Consular And Trade Reports, No. 134, JUNE 9TH. P. 1087.Canada, QuebecBlank
DS1985-0380
1985
Lang, R.D.Lang, R.D.Argyle - a New DevelopmentAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) PREPRINT., No. 85-40, 6P.Australia, Western AustraliaHistory, Exploration Techniques, Mining Methods, Marketing, Prod
DS1986-0480
1986
Lang, R.D.Lang, R.D.Development of Australia's first major diamond discovery outlinedMining Engineering, Vol. 38, No. 1, January pp. 13-16GlobalArgyle, treatment plant, Economics
DS201412-0497
2014
Langdon, J.Langdon, J.Diamonds will shine brightly in 2014 .. Experts agree.International Resource Journal, Jan. pp. 26-29.GlobalEconomics
DS2003-0772
2003
Lange, G.M.Lange, G.M., Hassan, R., Alfieri, A.Using environmental accounts to promote sustainable development: experience inNatural Resources Forum, Vol. 27, 1, pp. 19-31.South AfricaSustainability - not specific to diamonds
DS200412-1083
2003
Lange, G.M.Lange, G.M., Hassan, R., Alfieri, A.Using environmental accounts to promote sustainable development: experience in southern Africa.Natural Resources Forum, Vol. 27, 1, pp. 19-31.Africa, South AfricaSustainability - not specific to diamonds
DS1994-0982
1994
Lange, R.Lange, R.Subcontinental lithosphere: preservation of complex interactions, asthenospheric plumes and subducted slabs.Eos, Vol. 75, No. 16, April 19, p. 188.MantlePlumes, Subduction
DS1990-0901
1990
Lange, R.A.Lange, R.A., Carmichael, I.S.E.Hydrous basaltic andesites associated with minette and related lavas in western MexicoJournal of Petrology, Vol. 31, pt. 6, pp. 1225-1259MexicoMinettes, Petrology
DS1991-0951
1991
Lange, R.A.Lange, R.A., Carmichael, I.S.E.A potassic volcanic front in western Mexico: the lamprophyric and related lavas of San SebastianGeological Society of America Bulletin, Vol. 103, No. 7, July pp. 928-940MexicoMinette, absarokite, Volcanics, Geochemistry
DS1993-0435
1993
Lange, R.A.Feldstein, S.N., Lange, R.A., Vennemann, T., O'Neil, J.R.Complete chemical analyses and D/H ratios of phlogopite: the importance Of the Oxy-annite component.American Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 636.GlobalExperimental petrology, Phlogopite
DS2000-0549
2000
Lange, R.A.Lange, R.A.Plio-Pleistocene paleomagnetism of the Leucite Hills volcanics revisited (Wyoming).Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-173.WyomingLamproite, Deposit - Leucite Hills
DS201212-0726
2012
Lange, R.A.Thoma, C.W., Liu, Q., Agee, C.B., Asimov, P.D., Lange, R.A.Multi-technique equation for Fe2SiO4 melt and the density of Fe bearing silicate melts from 0 to 161 Gpa.Journal of Geophysical Research, Vol. 117, 18p. B10206TechnologyMantle mineralogy
DS201508-0370
2015
Lange, R.A.O'Leary, M.C., Lange, R.A., Ai, Y.The compressability of CaCO3-Li2CO3-Na2CO3-K2CO3 liquids: application to natrocarbonatite and CO2- bearing nephelinite liquids from Oldoinyo Lengai.Contributions to Mineralogy and Petrology, Vol. 170, 18p.Africa, TanzaniaDeposit - Oldoinyo Lengai
DS202010-1859
2020
Lange, T.Lorenz, V., Lange, T.The volcanic field of the Swabian Alb in southern Germany. *** GERJber. Mitt. oberrhein. Geol. Ver. N.F. English abstract, Vol. 102, pp. 153-174. 22p. PdfEurope, Germanymelilitite
DS202010-1860
2020
Lange, T.Lorenz, V., Lange, T., Buchel, G.The volcanoes of the Westeifel, Germany. ***GERJber. Mitt. oberrhein. Geol. Ver. N.F. English abstract, Vol. 102, pp. 379-411. 33p. PdfEurope, Germanymaars
DS202010-1855
2019
Lange, V.T.Lange, V.T., Lorenz, V., Koppen, K-H, Buchel, G.New aspects of the volcanism of the West Eifel. *** GERJber. Mitt. oberrhein. Geol. Ver. N.F. English abstract, Vol. 101, pp. 227-250. 24p. PdfEurope, Germany guidebook
DS1983-0236
1983
Langel, R.Frey, H., Langel, R., et al.Pogo and PangeaTectonophysics, Vol. 95, No. 3-4, PP. 181-190.South Africa, Africa, South AmericaTectonics, Magsat
DS1991-0952
1991
Langel, R.A.Langel, R.A.Study of the crust and mantle using magnetic surveys by magsat and othersatellitesP.il.a.s.-ear, Vol. 99, No. 4, December pp. 581-618GlobalGeophysics -magnetics, Remote sensing
DS1995-1550
1995
Langel, R.A.Ravat, D., Langel, R.A., Alsdorf, D.E.Global vector and scalar MAGSAT magnetic anomaly mapsJournal of Geophysical Research, Vol. 100, No. 10, Oct, 10, pp. 111-136.GlobalGeophysics -magnetics, Magsat
DS1996-1144
1996
Langel, R.A.Purucker, M.E., Sabaka, T.J., Langel, R.A.Conjugate gradient analyses - a new tool for studying satellite magneticdat a setsGeophys. Research Letters, Vol. 23, No. 5, March 1, pp 507-510GlobalRemote sensing, Geophysics -magnetics
DS1975-0322
1976
Lange-Mechlen, S.Lange-Mechlen, S.Edelstein. #1Stuttgart: Belser Verlag, 120P.GlobalKimberlite
DS1996-0805
1996
Langenberg, C.W.Langenberg, C.W., Skupinski, A.The provenance of diamond indicator minerals in bedrock of the Hinton @ Alberta Foothills.Alberta Geological Survey, MIN 19960008, 66p. $ 10.00Alberta, west centralExploration - assessment
DS1998-0827
1998
Langenberg, C.W.Langenberg, C.W., Skupinski, A.Indications of ultramafic volcanism in bedrock of the Wapiti area, west central Alberta.Calgary Mining Forum, Apr. 8-9, p. 62. poster abstractAlbertaSampling - heavy minerals, Diatremes, dikes
DS1999-0284
1999
Langenberg, C.W.Hamilton, W.N., Price, M.C., Langenberg, C.W.Geological map of AlbertaAlberta Geological Survey, 1:1, 000, 000AlbertaMap - not specific to diamonds
DS1999-0392
1999
Langenberg, C.W.Langenberg, C.W., Skupunski, A.Remnants of ultramafic igneous rocks in bedrock of the Wapiti area, west central Alberta.8th. Calgary Mining forum, 1p. abstractAlbertaGeochemistry - indicator minerals
DS2000-0550
2000
Langenberg, C.W.Langenberg, C.W., Skupinski, A.Remnants of (possibly diamondiferous) ultramafic igneous rocks in bedrock of Kakwa/Wapiti area.Alberta Geological Survey, Earth Science Report 00-03, 45p. $15.00Alberta, west centralExploration - assessment
DS200912-0758
2009
Langenheim, V.Thurber, C., Zhang, H., Brocher, T., Langenheim, V.Regional three dimensional seismic velocity model of the crust and uppermost mantle of northern California.Journal of Geophysical Research, Vol. 114, B01304.United States, CaliforniaGeophysics - seismics
DS1995-1052
1995
Langenheim, V.E.Langenheim, V.E.Gravity of the New Madrid seismic zone - a preliminary studyUnited States Geological Survey (USGS) Prof. paper, No. 1538- L, 18p.MidcontinentGeophysics - seismics, Mississippi Embayment
DS1995-1053
1995
Langenheim, V.E.Langenheim, V.E.Gravity of the New Madrid seismic zone: a preliminary studyUnited States Geological Survey (USGS) Prof. Paper, No. P1538-L, L1-18Missouri, Arkansas, Kentucky, TennesseeGeophysics -gravity, Midcontinent
DS1997-0523
1997
LangenhorstHough, R.M., Gilmour, I., Pillinger, C.T., LangenhorstDiamonds from the iridium rich K-T boundary layer at Arroyo el Mimbral, Tamaulipas, Mexico.Geology, Vol. 25, No. 11, Nov. pp. 1019-22.MexicoK-T boundary, Diamonds - mineralogy, techniques
DS1999-0813
1999
Langenhorst, A.Wysession, M.E., Langenhorst, A., Clarke, T.J.Lateral variations in compressional/shear veolocities at the base of themantle.Science, Vol. 284, No. 5411, Apr. 2, pp. 120-4.MantleGeophysics - seismics, Tectonics
DS1999-0393
1999
Langenhorst, F.Langenhorst, F., Shafranovsky, Masaitis, KoivistoDiscovery of impact diamonds in a Fennoscandian crater and evidence #NAME? solid state transformation.Geology, Vol. 27, No. 8, Aug. pp. 747-50.Finland, Baltic StatesDiamond genesis, Lappajarvi Crater
DS2002-0914
2002
Langenhorst, F.Langenhorst, F., Poirier, J.P.Transmission electron microscopy of coesite inclusions in the Dora Maira high pressure metamorphic pyrope quartzite.Earth and Planetary Science Letters, Vol. 203, 3-4, pp. 793-803.EuropeCoesite - inclusions, UHP, ultra high pressure
DS2002-1023
2002
Langenhorst, F.McCammon, C., Lauterbach, S., Van Akern, P., Langenhorst, F., Seifert, F.EELS studies of lower mantle mineral assemblages: a window to redox conditions18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.77.MantleUHP mineralogy - perovskite
DS2003-0354
2003
Langenhorst, F.Dubrovinsky, L., Dubrovinskaia, N., Langenhorst, F., Dobson, D., Robie, D.Iron silica interaction at extreme conditions and the electrically conducting layer at theNature, No. 6927, March 6, pp. 58-60.MantleCore mantle boundary, Geochemistry
DS2003-0823
2003
Langenhorst, F.Litasov, K., Ohtani, E., Langenhorst, F., Yurimoto, H., Kubo, T., Kondo, T.Water solubility in Mg perovskites and water storage capacity in the lower mantleEarth and Planetary Science Letters, Vol. 211, 1-2, June 15, pp. 189-203.MantleWater storage
DS2003-0824
2003
Langenhorst, F.Litasov, K., Ohtani, E., Langenhorst, F., Yurimoto, H., Kubo, T., Kondo, T.Water solubility in Mg perovskites and water storage capacity in the lower mantleEarth and Planetary Science Letters, Vol. 211, 1-2, pp. 189-203.MantleBlank
DS2003-1300
2003
Langenhorst, F.Smyth, J.R., Holl, C.M., Frost, D.J., Jacobsen, S.D., Langenhorst, F.Structural systematics of hydrous ring woodite and water in Earth's interiorAmerican Mineralogist, Vol. 88, 10, Oct. pp. 1402-7.MantleMineralogy
DS200412-0585
2004
Langenhorst, F.Frost, D.J., Liebske, C., Langenhorst, F., McCammon, C.A., Tronnes, R.G., Rubie, D.C.Experimental evidence for the existence of iron rich metal in the Earth's lower mantle.Nature, No. 6981, March 25, pp. 409-411.MantleSulphides
DS200412-0586
2004
Langenhorst, F.Frost, D.J., Liebske, C., McCammon, C.A., Langenhorst, F., Tronnes, R., Rubie,D.C.Experimental evidence for the existence of a metallic iron rich phase in the Earth's mantle.Lithos, ABSTRACTS only, Vol. 73, p. S38. abstractMantleRedox conditions
DS200412-1144
2003
Langenhorst, F.Litasov, K., Ohtani, E., Langenhorst, F., Yurimoto, H., Kubo, T., Kondo, T.Water solubility in Mg perovskites and water storage capacity in the lower mantle.Earth and Planetary Science Letters, Vol. 211, 1-2, June 15, pp. 189-203.MantleWater storage
DS200412-1258
2004
Langenhorst, F.McCammon, C.A., Lauterbach, S., Seifert, F., Langenhorst, F., Van Aken, P.A.Iron oxidation state in lower mantle mineral assemblages. Part 2.Earth and Planetary Science Letters, Vol. 222, 2, pp. 435-449.MantleMineral chemistry
DS200412-1269
2004
Langenhorst, F.McEnroe, S.A., Langenhorst, F., Robinson, P., Bromiley, G.D., Shaw, C.S.J.What is magnetic in the lower crust?Earth and Planetary Science Letters, Vol. 226, 1-2, Sept. 30, pp.175-192.MantleMagnetic anomalies, hematite-ilmenite, Curie isotherm
DS200412-1863
2003
Langenhorst, F.Smyth, J.R., Holl, C.M., Frost, D.J., Jacobsen, S.D., Langenhorst, F., McCammon, C.A.Structural systematics of hydrous ring woodite and water in Earth's interior.American Mineralogist, Vol. 88, 10, Oct. pp. 1402-7.MantleMineralogy
DS200512-0444
2005
Langenhorst, F.Holzapel, C., Rubie, D.C., Frost, D.J., Langenhorst, F.Geophysics: Fe Mg interdiffusion in (Mg,Fe) SiO3 perovskite and lower mantle requilibration.Science, No. 5741, Sept. 9, pp. 1707-1710.MantleGeophysics
DS200712-0593
2007
Langenhorst, F.Langenhorst, F., Solozhenko, V.L.ATEM-EELS study of diamond like phases in the B-C-N system.Plates, Plumes, and Paradigms, 1p. abstract p. A542.TechnologyB-C-N compounds
DS200712-0726
2007
Langenhorst, F.Mierdel, K., Keppler, H., Smyth, J.R., Langenhorst, F.Water solubility in aluminous orthopyroxene and the origin of the Earth's asthenosphere.Science, Vol. 315, Jan. 19, pp. 364-368.MantleTectonics
DS201112-0635
2010
Langenhorst, F.Malaspina, N., Scambelluri, M., Poli, S., Van Roermund, H.L.M., Langenhorst, F.The oxidation state of mantle wedge majoritic garnet websterites metasomatised by C-bearing subduction fluids.Earth and Planetary Science Letters, Vol. 298, 3-4, pp. 417-426.MantleMetasomatism
DS201212-0098
2012
Langenhorst, F.Bureau, H., Langenhorst, F., Auzende, A-L., Frost, D.J., Esteve, I., Siebert, J.The growth of fibrous, cloudy and polycrystalline diamonds.Geochimica et Cosmochimica Acta,, Vol. 77, pp. 202-214.TechnologyDiamond morphology
DS201212-0187
2012
Langenhorst, F.Escudero, A., Miyajima, N., Langenhorst, F.Microstructure, composition and P-T conditions of rutile from Diamondiferous gneiss of the Saxonian Erzgebirge Germany.Chemie der Erde, Vol. 72, 1, pp. 25-30.Europe, GermanyUHP
DS201212-0188
2012
Langenhorst, F.Escudero, A., Myyajima, N., Langenhorst, F.Microstructure, composition and P-T conditions of rutile from Diamondiferous gneiss of the Saxonian Ezgebirge, Germany.Chemie Der Erde, Vol. 72, 1, pp. 25-30.Europe, GermanyUHP , geothermometry
DS201212-0395
2012
Langenhorst, F.Langenhorst, F., Deutsch, A.Shock metamorphism of minerals.Elements, Vol. 8, 1, Feb. pp. 31-36.TechnologyHP, melting
DS201212-0433
2012
Langenhorst, F.Malaspina, N., Langenhorst, F., Fumagalli, P., Tumiati, S., Poli, S.Fe 3+ distribution between garnet and pyroxenes in mantle wedge carbonate bearing garnet peridotites ( Sulu, China) and implications for their oxidation state.Lithos, Vol. 146-147, pp. 11-17.ChinaUHP
DS201212-0434
2012
Langenhorst, F.Malaspina, N., Langenhorst, F., Fumagalli, P., Tumiati, S., Poli, S.Fe 3 + distribution between garnet and pyroxenes in mantle wedge carbonate bearing garnet peridotites ( Sulu China) and implications for their oxidation state.Lithos, Vol. 146-147, pp. 11-17.ChinaUHP
DS201212-0435
2012
Langenhorst, F.Malaspina, N., Langenhorst, F., Poli, S.C-O-H metasomatism and redox processes in the mantle at subduction zones.emc2012 @ uni-frankfurt.de, 1p. AbstractChinaSulu area
DS201312-0569
2013
Langenhorst, F.Malaspina, N., Langenhorst, F.Fluid induced redox processes at the slab mantle interface: insights from ultrahigh pressure garnet peridotites.Goldschmidt 2013, AbstractMantleRedox
DS201412-0711
2014
Langenhorst, F.Prescher, C., Langenhorst, F., Dubrovinsky, L.S., Prakapenka, V.B., Miyajima, N.The effect of Fe spin crossovers on its partitioning behavior and oxidation state in a pyrolitic Earth's lower mantle system.Earth and Planetary Science Letters, Vol. 399, pp. 86-91.MantleOxidation
DS201904-0755
2018
Langenhorst, F.Langenhorst, F., Campione, M.Ideal and real structures of different forms of carbon, with some remarks on their geological significance.Journal of the Geological Society of London, Vol. 176, pp. 337-347.Globalcarbon

Abstract: Carbon is found in nature in a huge variety of allotropic forms and recent research in materials science has encouraged the development of technological materials based on nanocarbon. Carbon atoms with sp2 or sp3 hybridization can be thought of as building blocks. Following a bottom-up approach, we show how graphene and diamond molecules are built up and how their properties vary with size, reaching an upper limit with bulk graphite and diamond. Carbon atoms with sp2 hybridization give rise to an impressive number of different materials, such as carbon nanotubes, graphene nanoribbons, porous carbon and fullerene. As in any crystalline phase, the crystal structures of natural carbon allotropes (i.e. graphite and diamond) contain various types of imperfections. These so-called lattice defects are classified by their dimensions into 0D (point), 1D (line), 2D (planar) and 3D (volume) defects. Lattice defects control the physical properties of crystals and are often a fingerprint of the geological environment in which they formed and were modified. Direct observations of lattice defects are commonly accomplished by transmission electron microscopy. We present and discuss the ideal and real structures of carbon allotropes, the energetics of lattice defects and their significance in understanding geological processes and conditions.
DS201605-0872
2016
Langenhoven, J.Mokgalaka, L., Langenhoven, J., du Toit, R.Progress update on the Petra Diamonds' MTS 3D SpatialDB integration and reporting project.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 239-250.Africa, South AfricaMining - applied
DS1991-1356
1991
Langer, K.Platonov, A.N., Langer, K., Matsuk, S.S., Taran, M.N., Hu, X.iron 2 Ti4 Charge transfer in garnets from mantle eclogitesEuropean Journal of Mineralogy, Vol. 3, No. 1, pp. 19-26GlobalMineralogy, Eclogites -garnet
DS1993-0878
1993
Langer, K.Langer, K., et al.Single crystal spectra of garnets from Diamondiferous high-pressure metamorphic rocks from Kazakhstan; indications for Oh, H2O and FeTi chargetransfer.European Journal of Mineralogy, Vol. 5, No. 6, Dec. pp. 1091-1100.GlobalMineral chemistry, Kokchetav Massif
DS1993-0879
1993
Langer, K.Langer, K., Robarick, E., Sobolev, N.V., Shatsky, V.S.Single crystal spectra of garnets from Diamondiferous high pressure metamorphic rocks from Kazakhstan -indications for OH-,H2O, and FeTi chargetransfer.European Journal of Mineralogy, Vol. 5, No. 6, Nov-Dec pp. 1091-1100.Russia, KazakhstanMetamorphic rocks, Mineralogy -garnets
DS1998-0965
1998
Langer, K.Matsyuk, S.S., Langer, K., Hosch, A.Hydroxyl defects in garnets from mantle xenoliths in kimberlites of the Siberian Platform #2Contributions to Mineralogy and Petrology, Vol. 132, No. 2, pp. 163-179.Russia, SiberiaMantle xenoliths, Petrology
DS1998-0966
1998
Langer, K.Matsyuk, S.S., Langer, K., Hosch, A.Hydroxyl defects in garnets from mantle xenoliths in kimberlites of the Siberian Platform #1Contributions to Mineralogy and Petrology, Vol. 133, No. 4, pp. 418-.Russia, SiberiaXenoliths, Garnets
DS2001-0597
2001
Langer, K.Khisina, N.R., Wirth, R., Langer, K., Andrut, UkhanovMicrostructure of experimentally oxidized olivine from a mantle nodule 1. modes of Fe3 and OH occurrence.Geochemistry International, Vol. 39, No. 4, pp. 327-35.GlobalPetrology - experimental, Nodule
DS200412-1247
2004
Langer, K.Matsyuk, S.S., Langer, K.Hydroxl in olivines from mantle xenoliths in kimberlites of the Siberian platform.Contributions to Mineralogy and Petrology, Vol. 147, 4, pp. 413-437.Russia, SiberiaMineral chemistry
DS200412-1965
2004
Langer, K.Taran, M.N., Kvasnytsya, V.M., Langer, K.On unusual deep violet microcrystals of diamonds from placers of Ukraine.European Journal of Mineralogy, Vol. 16, 2,pp. 241-245.Europe, UkraineDiamond morphology
DS200612-1415
2006
Langer, K.Taran, M.N., Kvasnytsya, V.M., Langer, K., Ilchenko, K.O.Infrared spectroscopy study of nitrogen centers in microdiamonds from Ukrainian Neogene placers.European Journal of Mineralogy, Vol. 18, 1, pp. 71-81.Europe, Ukraine, RussiaMicrodiamonds
DS1995-0978
1995
Langer, W.H.Knepper. D.H., Langer, W.H., Miller, S.Survey of natural aggregate properties characteristics important in remotesensing, Air- geophysics.Nonrenewable Resources, Vol. 4, No. 1, Spring pp. 99-120.GlobalRemote sensing, airborne geophysics, Alluvials - gravels not specific to diamonds
DS1997-0506
1997
Langereis, C.G.Hilgen, F.J., Krijgsman, W., Langereis, C.G., Lourens, L.Breakthrough made in dating of the geological recordEos, Vol. 78, No. 28, July 15, p. 285, 288, 289GlobalTimescale, Sedimentary cycles
DS2003-1342
2003
Langereis, C.G.Strik, G., Blake, T.S., Zegers, T.E., White, S.H., Langereis, C.G.Paleomagnetism of flood basalts in the Pilbara Craton, Western Australia: Late ArcheanJournal of Geophysical Research, Vol. 108, No. B 12, Dec. 3, 10.1029/2003JB002475AustraliaGeophysics - paleomagnetics, tectonics
DS200412-1937
2003
Langereis, C.G.Strik, G., Blake, T.S., Zegers, T.E., White, S.H., Langereis, C.G.Paleomagnetism of flood basalts in the Pilbara Craton, Western Australia: Late Archean continental drift and the oldest known reJournal of Geophysical Research, Vol. 108, No. B 12, Dec. 3, 10.1029/2003 JB002475AustraliaGeophysics - paleomagnetics, tectonics
DS1997-0649
1997
Langerheim, V.E.Langerheim, V.E., Hildenbrand, T.G.Commerce geophysical lineament - its source, geometry and relationship to Reelfoot Rift and New Madrid zone.Geological Society of America (GSA) Bulletin., Vol. 109, No. 5, May pp. 580-595.Arkansas, Tennessee, Kentucky, MissouriTectonics, Rifting
DS200712-1048
2007
Langeris, C.G.Strik, G., De Wit, M.J., Langeris, C.G.Paleomagnetism of the NeoArchean Pongola and Ventersdorp Supergroups and an appriasal of the 3.0 - 1.9 Ga apparent polar wander path of Kaapvaal CratonPrecambrian Research, Vol. 153, 1-2, pp. 96-115.Africa, South AfricaPaleomagnetism
DS1994-0983
1994
Langfield, J.Langfield, J.Gem of gems... diamondAustralian Gold Gem and Treasure, pp. 31-33.AustraliaNews item, Argyle -layman's notes
DS2002-0915
2002
Langford, C.Langford, C.Man vs manufacturing... high cost environment and difficulties in finding skilled labourCanadian Diamonds, Fall, pp. 34-6.CanadaDiamond - cutting
DS2002-0916
2002
Langford, C.Langford, C.A cut above... risky business but diamond manufacturing has become a part of daily life in the north.Canadian Diamonds, p. 36.Northwest TerritoriesNews item, Diamond cutters
DS2003-0773
2003
Langford, C.Langford, C., Kennedy, J.Diavik: Canada's next big stepCanadian Diamonds, Spring, pp. 30-38, 49.Northwest TerritoriesDeposit - Diavik
DS200412-1084
2003
Langford, C.Langford, C., Kennedy, J.Diavik: Canada's next big step.Canadian Diamonds, Spring, pp. 30-38, 49.Canada, Northwest TerritoriesMining Deposit - Diavik
DS201201-0854
2011
Langford, N.K.Lee, K.C., Sprague, M.R., Sussman, B.J., Nunn, J., Langford, N.K., Jin, X-M., Champoin, T., et al.Entangling microscopic diamonds at room temperature. ( quantum technology)Science, Vol. 334, no. 6060, Dec. 2, pp. 1253-1256.TechnologyQuantum state of diamonds
DS1970-0951
1974
Langford, R.E.Langford, R.E.A Study of the Origin of Arkansaw Diamonds by Mass Spectrometry.Ph.d. Thesis, University of Georgia, Athens, United States, Gulf Coast, Arkansas, PennsylvaniaGenesis, Isotope Chemistry
DS1975-0789
1978
Langford, R.E.Langford, R.E.The Origin of Diamonds, Theoretical StudyJournal of KOREAN CHEMICAL SOCIETY, Vol. 22, No. 3, PP. 138-149.GlobalChemistry, Genesis, Theory, Natural Diamond, Spectrometry, Inclusions
DS1989-0849
1989
Langford, R.P.Langford, R.P., Chan, M.A.Fluvial-aeolian interactions: Part 1. modern systems Part II. ancientsystemsSedimentology, Vol. 36, No. 6, December pp. 1023-1052GlobalGeomorphology, Sedimentology -fluvial systems
DS1989-1416
1989
Langham, C.D.Sneath, P.H.A., Langham, C.D.OUTLIER: a BASIC program for detecting outlying members of multivariate clusters based on presence-absencedataComputers and Geosciences, Vol. 15, No. 6, pp. 939-964GlobalComputer, Program -OUTLIER.
DS201809-2035
2018
Langhof, J.Holtstam, D., Camara, F., Skogby, H., Karlsson, A., Langhof, J.Description and recognition of potassic richterite, an amphibole supergroup mineral from the Pajsberg ore field, Varmland, Sweden.Mineralogy and Petrology, doi.org/101007/ s00710-018-0623-6 10p.Europe, Swedenalkaline

Abstract: Potassic-richterite, ideally AKB(NaCa)CMg5TSi8O22W(OH)2, is recognized as a valid member of the amphibole supergroup (IMA-CNMNC 2017-102). Type material is from the Pajsberg Mn-Fe ore field, Filipstad, Värmland, Sweden, where the mineral occurs in a Mn-rich skarn, closely associated with mainly phlogopite, jacobsite and tephroite. The megascopic colour is straw yellow to grayish brown and the luster vitreous. The nearly anhedral crystals, up to 4 mm in length, are pale yellow (non-pleochroic) in thin section and optically biaxial (-), with a?=?1.615(5), ß?=?1.625(5), ??=?1.635(5). The calculated density is 3.07 g•cm-1. VHN100 is in the range 610-946. Cleavage is perfect along {110}. EPMA analysis in combination with Mössbauer and infrared spectroscopy yields the empirical formula (K0.61Na0.30Pb0.02)?0.93(Na1.14Ca0.79Mn0.07)?2(Mg4.31Mn0.47Fe3+0.20)?5(Si7.95Al0.04Fe3+0.01)?8O22(OH1.82F0.18)?2 for a fragment used for collection of single-crystal X-ray diffraction data. The infra-red spectra show absorption bands at 3672 cm-1 and 3736 cm-1 for the a direction. The crystal structure was refined in space group C2/m to R1?=?3.6% [I >?2s(I)], with resulting cell parameters a?=?9.9977(3) Å, b?=?18.0409(4) Å, c?=?5.2794(2) Å, ??=?104.465(4)°, V?=?922.05(5) Å3 and Z?=?2. The A and M(4) sites split into A(m) (K+), A(2/m) (Na+), A(2) (Pb2+), and M(4') (Mn2+) subsites, respectively. The remaining Mn2+ is strongly ordered at the octahedrally coordinated M(2) site, possibly together with most of Fe3+. The skarn bearing potassic-richterite formed at peak metamorphism, under conditions of low SiO2 and Al2O3 activities and relatively high oxygen fugacities.
DS1920-0289
1926
Langley, C.E.H.Langley, C.E.H.The Union Diamond Industry in 1925Mining Engineering Journal of South Africa, Vol. 37, PT. 2, No. 1835, NOVEMBER 27TH. P. 333.South AfricaCurrent Activities
DS201709-2072
2017
Langman, J.Wilson, D., Amos, R., Blowes, D., Langman, J., Smith, L., Sego, D.Diavik waste rock project: scale up of a reactive transport conceptual model for temperature and sulfide dependent geochemical evolution.Goldschmidt Conference, abstract 1p.Canada, Northwest Territoriesdeposit, Diavik
DS201801-0081
2018
Langman, J.B.Wilson, D., Amos, R.T., Blowes, D.W., Langman, J.B., Ptacek, C.J., Smith, L., Sego, D.C.Diavik waste rock project: a conceptual model for temperature and sulfide content dependent geochemical evolution of waste rock - Laboratory scale.Applied Geochemistry, Vol. 89, pp. 160-172.Canada, Northwest Territoriesdeposit - Diavik

Abstract: The Diavik Waste Rock Project consists of laboratory and field experiments developed for the investigation and scale-up of the geochemical evolution of sulfidic mine wastes. As part of this project, humidity cell experiments were conducted to assess the long-term geochemical evolution of a low-sulfide waste rock. Reactive transport modelling was used to assess the significant geochemical processes controlling oxidation of sulfide minerals and their dependence on temperature and sulfide mineral content. The geochemical evolution of effluent from waste rock with a sulfide content of 0.16 wt.% and 0.02 wt.% in humidity cells was simulated with the reactive transport model MIN3P, based on a conceptual model that included constant water flow, sulfide mineral content, sulfide oxidation controlled by the availability of oxidants, and subsequent neutralization reactions with carbonate and aluminosilicate minerals. Concentrations of Ni, Co, Cu, Zn, and SO4 in the humidity cell effluent were simulated using the shrinking core model, which represented the control of oxidant diffusion to the unreacted particle surface in the sulfide oxidation process. The influence of temperature was accounted for using the Arrhenius relation and appropriate activation energy values. Comparison of the experiment results, consisting of waste rock differentiated by sulfide mineral content and temperature, indicated surface area and temperature play important roles in rates of sulfide oxidation and release of sulfate and metals. After the model was calibrated to fit the effluent data from the higher sulfide content cells, subsequent simulations were conducted by adjusting only measured parameters, including sulfide mineral content and surface area.
DS201809-2115
2018
Langman, J.B.Wilson, D., Amos, R.T., Blowes, D.W., Langman, J.B., Smith, L., Sego, D.C.Diavik waste rock project: Scale up of a reactive transport model for temperature and sulfide content dependent geochemical evolution of waste rock.Applied Geochemisty, Vol. 96, pp. 177-190.Canada, Northwest Territoriesdeposit - Diavik

Abstract: The Diavik Waste Rock Project, located in a region of continuous permafrost in northern Canada, includes complementary field and laboratory experiments with the purpose of investigating scale-up techniques for the assessment of the geochemical evolution of mine waste rock at a large scale. As part of the Diavik project, medium-scale field experiments (~1.5?m high active zone lysimeters) were conducted to assess the long term geochemical evolution and drainage of a low-sulfide waste rock under a relatively simple (i.e. constrained by the container) flow regime while exposed to atmospheric conditions. A conceptual model, including the most significant processes controlling the sulfide-mineral oxidation and weathering of the associated host minerals as observed in a laboratory humidity cell experiment, was developed as part of a previous modelling study. The current study investigated the efficacy of scaling the calibrated humidity cell model to simulate the geochemical evolution of the active zone lysimeter experiments. The humidity cell model was used to simulate the geochemical evolution of low-sulfide waste rock with S content of 0.053?wt.% and 0.035?wt.% (primarily pyrrhotite) in the active zone lysimeter experiments using the reactive transport code MIN3P. Water flow through the lysimeters was simulated using temporally variable infiltration estimated from precipitation measurements made within 200?m of the lysimeters. Flow parameters and physical properties determined during previous studies at Diavik were incorporated into the simulations to reproduce the flow regime. The geochemical evolution of the waste-rock system was simulated by adjustment of the sulfide-mineral content to reflect the values measured at the lysimeters. The temperature dependence of the geochemical system was considered using temperature measurements taken daily, adjacent to the lysimeters, to correct weathering rates according to the Arrhenius equation. The lysimeter simulations indicated that a model developed from simulations of laboratory humidity cell experiments, incorporating detailed representations of temporally variable temperature and water infiltration, can be scaled to provide a reasonable assessment of geochemical evolution of the medium-scale field experiments.
DS200612-0762
2006
Langmuir, C.Langmuir, C., Goldstein, S.Recycled eclogite as the fertile component of the depleted MORB source.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 3. abstract only.MantleEclogite
DS1988-0546
1988
Langmuir, C.H.Plank, T., Langmuir, C.H.An evaluation of the global variations in the major element chemistry of arc basaltsEarth and Planetary Science Letters, Vol. 90, No. 4, November 25, pp. 349-370GlobalBasalts- arc, Geochemistry
DS1989-0850
1989
Langmuir, C.H.Langmuir, C.H.Geochemical consequences of in situ crystallizationNature, Vol. 340, No. 6230, July 20, pp. 199-204GlobalGeochemistry, Crystallization
DS1990-0902
1990
Langmuir, C.H.Langmuir, C.H.Ocean ridges spring surprisesNature, Vol. 344, No. 6267, April 12, p. 585GlobalMantle, Plate tectonics -ocean ridges
DS1993-0880
1993
Langmuir, C.H.Langmuir, C.H.Deep thoughts on the mantleNature, Vol. 364, July 15, pp. 191-192MantlePetrology
DS1993-1244
1993
Langmuir, C.H.Plank, T., Langmuir, C.H.Tracing trace elements from sediment input to volcanic output at subductionzonesNature, Vol. 362, No. 6422, April 22, pp. 739-742GlobalSubduction, Tectonics
DS1994-0305
1994
Langmuir, C.H.Christie, D.M., Langmuir, C.H.Automated XY plots from microsoft EXCELComputers and Geosciences, Vol. 20, No. 1, pp. 47-52GlobalComputer Program, Program -Excel
DS1994-0984
1994
Langmuir, C.H.Langmuir, C.H.Petrogenesis: water and the solid earthNature, Vol. 369, No. 6483, June 30, p. 704MantlePetrology
DS1994-1195
1994
Langmuir, C.H.Miller, D.M., Goldstein, S.L., Langmuir, C.H.Cerium/lead and lead isotope ratios in arc magmas and the enrichment of lead in the continentsNature, Vol. 368, No. 6471, April 7, p. 514MantleGeochronology, Arc magmas
DS1995-0959
1995
Langmuir, C.H.Kinzler, R.J., Langmuir, C.H.Minute mantle meltsNature, Vol. 375, No. 6529, May 25, p. 274MantleMelts, Geochemistry
DS1995-0960
1995
Langmuir, C.H.Kinzler, R.J., Langmuir, C.H.Geochemistry -minute mantle meltsNature, Vol. 375, No. 6529, May 25, p. 274.MantleMelt, Geochemistry
DS1995-0961
1995
Langmuir, C.H.Kinzler, R.J., Langmuir, C.H.Minute mantle meltsNature, Vol. 375, May 25, pp. 274-275.MantleMelting, Olivine
DS1996-1236
1996
Langmuir, C.H.Ryan, J.G., Leeman, W.P., Morris, J.D., Langmuir, C.H.The boron systematics of intraplate lavas: implications for crust and mantle evolution.Geochimica et Cosmochimica Acta, Vol. 60, No. 3, Feb. pp. 415-422.MantleBoron
DS1997-0850
1997
Langmuir, C.H.Niu, Y., Langmuir, C.H., Kinzler, R.J.The origin of abyssal peridotites: a new perspectiveEarth and Plan. Sci. Letters, Vol. 152, No. 1-4, pp. 251-265.Mantle, ridgesMelting, Peridotites
DS1998-1169
1998
Langmuir, C.H.Plank, T., Langmuir, C.H.The chemical composition of subducting sediment and its consequences For the crust and mantle.Chemical Geology, Vol. 145, No. 3-4, Apr. 15, pp. 325-394.MantleMineral chemistry
DS2003-0046
2003
Langmuir, C.H.Asimov, P.D., Langmuir, C.H.The importance of water to oceanic mantle melting regimesNature, No. 6925, Feb. 20, pp. 815-20.MantleMelt - subduction
DS200412-0469
2004
Langmuir, C.H.Donnelly,K.E., Goldstein, S.L., Langmuir, C.H., Spiegelman, M.Origin of enriched ocean ridge basalts and implications for mantle dynamics.Earth and Planetary Science Letters, Vol. 226, 3-4, Oct. 15, pp. 347-366.MantleE-MORB, geochemistry, isotope, trace, convective mixing
DS200512-0500
2003
Langmuir, C.H.Katz, R.F., Spiegelman, M., Langmuir, C.H.A new parameterization of hydrous mantle melting.Geochemistry, Geophysics, Geosystems: G3, Vol. 4, 9, p. 1073 10.1029/2002 GC000433MantleMelting, water
DS201412-0162
2014
Langmuir, C.H.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
DS1989-0851
1989
Langran, G.Langran, G.A review of temporal database research and its use in GIS applicationsInternational Journal of Geographical Information Systems, Vol. 3, No. 3, July-September pp. 215-232GlobalGIS, Database research
DS1995-2035
1995
Langridge, R.J.Wasteneys, H.A., Clark, A.H., Farrar, E., Langridge, R.J.Grevillian granulite facies metamorphism in the Arequipa Massif Peru: a Laurentia Gondwana linkEarth and Plan. Sci. Letters, Vol. 132, pp. 63-73PeruCentral Andean orogenic basement, Arica Bight, Bolivian anticline
DS1990-0903
1990
Langseth, M.G.Langseth, M.G., Moore, J.C.Fluids in accretionary prisMEos, Vol. 71, No. 5, January 30, pp. 245-246GlobalTectonics, Subduction zones
DS2000-0722
2000
LangstonNyblade, A.A., Owens, T.J., Gurrola, Ritsema, LangstonSeismic evidence for a deep upper mantle thermal anomaly beneath east AfricGeology, Vol. 28, No. 7, July, pp. 599-602.Tanzania, Uganda, Kenya, East AfricaGeophysics - seismics, mantle, plume rift, Craton - Tanzanian
DS1990-0339
1990
Langston, C.A.Clouser, R.H., Langston, C.A.Upper mantle structure of southern Africa from PNI wavesJournal of Geophysical Research, Vol. 95, No. B 11, October 10, pp. 17403-17416South AfricaStructure, Mantle
DS1995-1368
1995
Langston, C.A.Nyblade, A.A., Langston, C.A.East African earthquakes below 20 km depth and their implications for crustal structure.Geophys. Journal, Vol. 121, pp. 49-62.East Africa, Kenya, Tanzania, Mozambique, Zaire, ZambiaTectonics
DS1996-1045
1996
Langston, C.A.Nyblade, A.A., Birt, C., Langston, C.A., Owens, T.J., LastSeismic experiment reveals rifting of Craton in TanzaniaEos, Vol. 77, No. 51, Dec. 17, p. 517, 521.TanzaniaGeophysics - seismics, Craton
DS1996-1046
1996
Langston, C.A.Nyblade, A.A., Vogfjord, K.S., Langston, C.A.P wave velocity of Proterozoic upper mantle beneath central and southernAsia.Journal of Geophysical Research, Vol. 101, No. 5, May 10, pp. 1159-72.AsiaMantle, Proterozoic
DS1999-0832
1999
Langston, C.A.Zhao, M., Langston, C.A., Owens, T.J.Upper mantle velocity structure beneath southern Africa from modeling regional seismic data.Journal of Geophysical Research, Vol. 104, No.3, Mar. 10, pp. 4783-94.South Africa, Botswana, TanzaniaGeophysics - seismics, Structure
DS2000-0721
2000
Langston, C.A.Nyblade, A.A., Langston, C.A., Owens, T.J.Seismic structure of the Tanzania Craton: implications for the stability of cratonic lithosphere.Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-164.Tanzania, East AfricaGeophysics - seismics, Craton - Tanzanian
DS1982-0357
1982
Langton, G.Langton, G.The South African Mining IndustryErzmetall., Vol. 35, No. 1, JANUARY PP. 20-26.South AfricaMining, Diamonds
DS1975-0790
1978
Langworthy, A.P.Langworthy, A.P., Black, L.P.The Mordor Complex: a Highly Differentiated Potassic Intrusion with Kimberlitic Affinities in Central Australia.Contributions to Mineralogy and Petrology, Vol. 67, PP. 51-62.AustraliaKimberlite, Carbonatite
DS1900-0578
1907
Lanier, R.S.Lanier, R.S.Has Arkansas a Diamond Field?Review of Reviews, Vol. 36, P. 301.United States, Gulf Coast, Arkansas, PennsylvaniaHistory, Geology, News Item
DS202012-2223
2020
Lanigan, P.M.P.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.
DS202012-2231
2020
Lanigan, P.M.P.McGuinness, C.D., Wassell, A.M., Lanigan, P.M.P., Lynch, S.A.Seperation of natural from laboratory-grown diamond using time -gated luminescence imaging.Gems & Gemology, Vol. 56, 2, summer pp. 220-229. pdfGloballuminescence
DS1989-0852
1989
Lankston, R.W.Lankston, R.W.The seismic refraction method: a viable tool for mapping shallow targets into the 1990'sGeophysics, Vol. 54, No. 12, December pp. 1535-1542GlobalGeophysics, Seismics
DS1970-0263
1971
Lanphere, M.A.Coleman, R.G., Lanphere, M.A.Distribution and Age of High-grade Blueschists, Associated Eclogites and Amphibolites from Oregon and California.Geological Society of America (GSA) Bulletin., Vol. 82, No. 9, PP. 2397-2412.GlobalEclogite
DS1975-0791
1978
Lanthier, L.R.Lanthier, L.R.Stratigraphy and Structure of the Lower Part of the Precambrian Libby Creek Group, Central Medicine Bow Mountains #1Msc. Thesis, University Wyoming, 30P.United States, Wyoming, Rocky Mountains, Medicine Bow MountainsRegional Studies
DS1975-1108
1979
Lanthier, R.Lanthier, R.Stratigraphy and Structure of the Lower Part of the Precambrian Libby Creek Group, Central Medicine Bow Mountains, Wyoming #2University WYOMING Contributions to Geology, Vol. 17, No. 2, PP. 135-147.GlobalKimberlite, Medicine Bow Mountains Rocky Mountains
DS1988-0400
1988
Lantuejoul ChLantuejoul ChOn the importance of choosing a change of support model for global reservesestimationMathematical Geology, Vol. 20, No. 8, November pp. 1001-1020. Database # 1757GlobalComputer, Program -Ore reserves
DS1995-1054
1995
Lanyon, R.Lanyon, R., Crawford, A.J., Eggins, S.M.Westward migration of Pacific Ocean upper mantle into Southern Ocean region between Australia and AntarcticaGeology, Vol. 23, No. 6, June pp. 511-514.Australia, AntarcticaTectonics, discordance, mantle, Geochronology
DS1995-1055
1995
Lanyon, R.Lanyon, R., Le Roex, A.P.Petrology of the alkaline and ultramafic lamprophyre associated with Okenyenya igneous complex, northeastSouth. African Journal of Geology, Vol. 98, No. 2, June pp. 140-156.NamibiaAlkaline rocks, Deposit -Okenyenya complex
DS1995-1056
1995
Lanyon, R.Lanyon, R., Le Roex, A.P.Petrogenesis of the lamprophyric intrusions associated with Damaral and igneous complexes, liquid immiscibilityEos, Vol. 76, No. 46, Nov. 7. p.F642-3. Abstract.NamibiaCarbonatite, lamprophyric diatremes, dikes, Damaraland
DS1998-0838
1998
Lanyon, R.Le Roex, A.P., Lanyon, R.Isotope and trace element geochemistry of Cretaceous Damaral and lamprophyres and carbonatites...Journal of Petrology, Vol. 39, No. 6, June 1, pp. 1117-46.NamibiaPlume - lithosphere interactions, Carbonatite, lamprophyres
DS1993-1139
1993
Lanz, T.Noakes, M., Lanz, T.Cost estimation handbook for the Australian mining industryAusIMM Sydney Branch, Mincost 90, Monograph No. 20 approx. $120.00AustraliaBook -table of contents, Cost estimation -Economics
DS201707-1307
2017
Lanzirotti, A.Bell, A.S., Shearer, C., Burger, P., Ren, M., Newville, M., Lanzirotti, A.Quantifying and correcting the effects of anisotropy in Xanes measurements of chromium valence in olivine: implications for a new olivine oxybarometer.American Mineralogist, Vol. 102, pp. 1165-1172.Technologyolivine

Abstract: Chromium valence ratios in igneous olivine may hold a wealth of redox information about the melts from which they crystallized. It has been experimentally shown that the Cr2+/?Cr of olivine varies systematically with fO2, therefore measurements of Cr valence in olivine could be employed as a quantitative oxybarometer. In situ synchrotron µ-XANES analyses of Cr valence ratios of individual olivine phenocrysts in thin section have the potential to unlock this stored magmatic redox information on a fine spatial scale. However, there are still obstacles to obtaining accurate XANES measurements of cation valence in crystalline materials, as the results from these measurements can be compromised by anisotropic absorption effects related to the crystallographic orientation of the sample. Improving the accuracy of XANES measurements of Cr valence ratios in olivine by calibrating an anisotropy correction is a vital step in developing Cr valence measurements in olivine as a rigorous oxybarometer. To accomplish this goal, we have used an integrated approach that combined experiments, electron backscatter diffraction analysis, and XANES measurements in olivine to systematically examine how orientation affects the resultant Cr K-edge XANES spectra and the Cr valence ratios that are calculated from them. The data set generated in this work was used to construct a model that mitigates the effects of anisotropy of the calculated Cr2+/?Cr values. The application of this correction procedure as a part of spectral processing improves the overall accuracy of the resultant Cr2+/?Cr values by nearly a factor of five. The increased accuracy of the XANES measured Cr valence ratios afforded by the anisotropy correction reduces the error on calculated fO2 values from approximately ±1.2 to ±0.25
DS201805-0984
2018
Lanzirotti, A.Tschauner, O., Huang, S., Greenberg, E., Prakapenka, V.B., Ma, C., Rossman, G.R., Shen, A.H., Zhang, D., Newville, M., Lanzirotti, A., Tait, K.Ice-VII inclusions in diamonds: evidence for aqueous fluid in the Earth's deep mantle. Orapa, ShandongScience, Vol. 359, pp. 1136-1139.Africa, South Africa, Botswana, Congo, Sierra Leone, Chinadiamond inclusions
DS201809-2021
2018
Lao-Davila, D.A.Fletcher, A.W., Abdelsalam, M.G., Emishaw, L., Atekwana, E.A., Lao-Davila, D.A., Ismail, A.Lithospheric controls on the rifting of the Tanzanian Craton at the Eyasi Basin, eastern branch of the East African Rift system.Tectonics, Aug 14, doi: 10.1029/2018 TC005065Africa, Tanzaniacraton

Abstract: Continental rifts most often nucleate within orogenic belts. However, some studies in the East African Rift System (EARS) have shown that continental rifts can also develop withincratons. This work investigated the ~1.5 Ma Eyasibasin,which propagates in a WSW direction into the Tanzanian craton. The basin is located where the Eastern Branch of the EARS transitions from a narrow rift (~70 km wide) thewider(~300 km wide) North Tanzanian Divergence. Unlike the rest of the Eastern Branch segments, the Eyasibasindoes not follow the Mozambique orogenic belt located on the eastern margin of the Tanzanian craton. This work generatedlithospheric-scale sections across the basinusing: (1) Digital Elevation Model to map surface rift-related brittle structures; (2) Aeromagnetic data to determine the depth to the Precambrian basement;and (3) World Gravity Model 2012 to estimatecrustal and lithospheric thickness by applying the two-dimensional(2D) radially-averaged power spectral analysis and 2D forward gravity modeling. These cross-sectionsshow that the Eyasibasinnucleates within a previously unidentified suture zone within the Tanzanian cratonand that this suture zone is characterized by thinner lithospherethat can be as thin as ~95 km. This zone ofthinner lithosphere is offset southeastwardfrom the surface expression of the Eyasibasinand might have facilitated the formation of other basins further south. Furthermore, the lithospheric thickness map indicates that the Tanzanian craton is heterogeneous and possibly composed of multiplesmaller cratonic fragments.
DS201412-0088
2014
Laouar, R.Caby, R., Bruguier, O., Fernandez, L., Hammor, D., Bosch, D., Mechati, M., Laouar, R., Ouabadi, A., Abdallah, N., Douchet, C.Metamorphic diamonds in a garnet megacryst from the Edough Massif (northeastern Algeria)… Recognition and geodynamic consequences.Tectonophysics, Vol. 637, pp. 341-353.Africa, AlgeriaEdough Massif
DS201709-1965
2017
Laouar, R.Bruguier, O., Bosch, D., Caby, R., Vitale-Brovarone, A., Fernadez, L., Hammor, D., Laouar, R., Ouabadi, A., Abdallah, N., Mechanti, M.Age of UHP metamorphism in the Western Mediterranean: insight from rutile and minute zircon inclusions in a diamond bearing garnet megacryst ( Edough Massif, NE Algeria).Earth and Planetary Science Letters, Vol. 474, pp. 215-225.Africa, Algeriadiamond inclusions

Abstract: Diamond-bearing UHP metamorphic rocks witness for subduction of lithospheric slabs into the mantle and their return to shallow levels. In this study we present U-Pb and trace elements analyses of zircon and rutile inclusions from a diamond-bearing garnet megacryst collected in a mélange unit exposed on the northern margin of Africa (Edough Massif, NE Algeria). Large rutile crystals (up to 300 µm in size) analyzed in situ provide a U-Pb age of 32.4 ± 3.3 Ma interpreted as dating the prograde to peak subduction stage of the mafic protolith. Trace element analyses of minute zircons (=30 µm) indicate that they formed in equilibrium with the garnet megacryst at a temperature of 740-810 °C, most likely during HP retrograde metamorphism. U-Pb analyses provide a significantly younger age of 20.7 ± 2.3 Ma attributed to exhumation of the UHP units. This study allows bracketing the age of UHP metamorphism in the Western Mediterranean Orogen to the Oligocene/early Miocene, thus unambiguously relating UHP metamorphism to the Alpine history. Exhumation of these UHP units is coeval with the counterclockwise rotation of the Corsica-Sardinia block and most likely resulted from subduction rollback that was driven by slab pull.
DS200612-0763
2005
Lapen, T.J.Lapen, T.J., Medaris, L.G., Johnson, C.M., Beard, B.L.Archean to middle Proterozoic evolution of Baltica subcontinental lithosphere:Contributions to Mineralogy and Petrology, Vol. 150, 2, pp. 131-145.Europe, Baltic ShieldTectonics
DS201212-0550
2012
Lapen, T.J.Peslier, A.H., Woodland, A.B., Bell, D.R., Lazarov, M., Lapen, T.J.Metasomatic control of water contents in the Kaapvaal cratonic mantle.Geochimica et Cosmochimica Acta, Vol. 97, pp. 213-246.Africa, South Africa, LesothoDeposit - Finsch, Kimberley, Jagersfontein, Letseng, Liqhobong
DS201312-0592
2013
Lapen, T.J.McCelland, W.C., Lapen, T.J.Linking time to the pressure temperature path of ultrahigh pressure rocks.Elements, Vol. 9, 4, August in pressMantleUHP
DS201412-0015
2014
Lapen, T.J.Armytage, R.M.G., Brandon, A.D., Peslier, A.H., Lapen, T.J.Osmium isotope evidence for Early to Middle Proterozoic mantle lithosphere stabilization and concommitant production of juvenile crust in Dish Hill, CA peridotite xenoliths.Geochimica et Cosmochimica Acta, Vol. 137, pp. 113-133.United States, CaliforniaSCLM, subduction
DS201702-0238
2017
Lapen, T.J.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.
DS2001-1152
2001
Lapenna, V.Telesca, L., Cuomo, V., Lapenna, V., Macchiato, M.Statistical analysis of fractal properties of point processes modeling seismic sequencesPhysics of the Earth and Planetary Interiors, Vol. 125, No. 1-4, pp. 65-83.GlobalGeophysics - seismics, Experimental
DS1960-0365
1963
Lapham, D.M.Lapham, D.M., Mckague, H.L.Deformation of Serpentinites in the Piedmont of PennsylvaniaGeological Society of America (GSA) SPECIAL PAPER., No. 73, P. 45. (abstract.).Appalachia, PennsylvaniaGeology
DS1960-0469
1964
Lapham, D.M.Lapham, D.M., Bassett, W.A.Potassium-argon Dating of Rocks and Tectonic Events in Piedmont of Southeastern Pennsylvania.Geological Society of America (GSA) SPECIAL PAPER., No. 73, PP. 661-667.Appalachia, PennsylvaniaGeochronology
DS2001-0907
2001
LapidoPereira, F., Bilal, E., Moutte, Lapido, Gruffat, AlbertDissolution of apatite ore from Angico Dos Dias carbonatite Complex and recovery of rare earth elementsJournal of South African Earth Sciences, Vol. 32, No. 1, p. A 28.(abs)BrazilCarbonatite, Angico Dos Dias
DS1983-0386
1983
Lapido loureiro, F.E.Lapido loureiro, F.E., Tavares, J.R.Duas Novas Ocorrencias de Carbonatitos: Mato Preto E Barra Do Rio Itapirapua.Revista Brasileira De Geociencias, Vol. 13, No. 1, PP. 7-11.BrazilCarbonatite, Related Rocks
DS1991-0479
1991
Lapido-LoureiroFilho, A.I., Dos Santos, A.B.R.M., Riffel, B.F., Lapido-LoureiroAspects of the geology, petrology and chemistry of Angolan carbonatitesJournal of Geochemical Exploration, Special Publications Geochemical Exploration, Vol. 40, No. 1-3, pp. 205-226AngolaCarbonatite, Petrology
DS1970-0744
1973
Lapido-Loureiro, F.E.Lapido-Loureiro, F.E.Carbonatitis de AngolaMems Trab. Institute Invest. Cient. Angola., No. 11, 42P.Angola, West AfricaCarbonatite
DS1993-0077
1993
Lapido-Loureiro, F.E.Barbosa, J., Lapido-Loureiro, F.E.Rare earths in Brasil: deposits, identified resources and politicsRare earth Minerals: chemistry, origin and ore deposits, International Geological Correlation Programme (IGCP) Project, pp. 7-9. abstractBrazilRare earths, Economics
DS2003-0958
2003
Lapidus, I.V.Mironov, Y.V., Ryakhovsky, V.M., Putovoy, A.A., Lapidus, I.V.Mantle plumes and isotopic heterogeneity of the mantle: evidence from the Atlantic andDoklady Earth Sciences, Vol. 391, 5, pp. 714-17.MantleGeochemistry, Alrosa
DS200412-1332
2003
Lapidus, I.V.Mironov, Y.V., Ryakhovsky, V.M., Putovoy, A.A., Lapidus, I.V.Mantle plumes and isotopic heterogeneity of the mantle: evidence from the Atlantic and adjacent continents.Doklady Earth Sciences, Vol. 391, 5, pp. 714-17.MantleGeochemistry
DS2002-1356
2002
LapierreRolland, Y., Picard, C., Pecher, Lapierre, Bosch, KellerThe Cretaceous Ladakh arc of NW Himalaya slab melting and melt mantle interaction during fast northward driftChemical Geology, Vol.182, 2-4, Feb.15, pp.139-78.India, northwest HimalayasMelting, slab subduction, Indian Plate
DS1987-0170
1987
Lapierre, H.Dupont, P.L., Lapierre, H., Gravelle, BertrandCaracterisation du magmatism Proterozoique superieur en Afrique de l'ouestet implications geodynamiques: rrifts intracratoniques au Panafricain?Canadian Journal of Earth Sciences, Vol. 24, pp. 96-109.GlobalAlkaline rocks, magmatism
DS1996-0214
1996
Lapierre, H.Campos, C., Charvet, J., Lapierre, H.Evidence of a Middle Late Devonian tectonic event in the Eastern Klamathterrane, northern CaliforniaGsn Proceedings Geol. Ore Dep. American Cordillera, Vol. 2, pp. 823-838CaliforniaTectonics
DS1998-0828
1998
Lapierre, H.Lapierre, H., Arculus, R., Ballevre, M., Bosch, D.Accreted eclogites with oceanic plateau basalt affinities in EcuadorMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 852-3.EcuadorRaspas Formation, MetmorphisM., Eclogites
DS1999-0018
1999
Lapierre, H.Arculus, R.J., Lapierre, H., Jaillard. E.Geochemical window into subduction and accretion processes: Raspas metamorphic complex, Ecuador.Geology, Vol. 27, No. 6, June, pp. 547-50.EcuadorLithosphere, subduction, Geochemistry - Raspas
DS2001-1150
2001
Lapierre, H/. StruikTardy, M., Lapierre, H/. Struik, Bosch, BrunetThe influence of mantle plume in the genesis of Cache Creek oceanic igneous rocks: geodynamic evolution...Canadian Journal of Earth Sciences, Vol. 38, No. 4, Apr. pp. 515-34.British Columbia, CordilleraMantle plume - not specific to diamonds
DS200712-0594
2007
Lapin, A.Lapin, A., Tolstov, A., Antonov, A.Sr and Nd isotopic compositions of kimberlites and associated rocks of the Siberian Craton.Doklady Earth Sciences, Vol. 413, 3, pp. 557-560.RussiaGeochronology
DS200712-0595
2007
Lapin, A.Lapin, A., Tolstov, A., Antonov, A.Sr and Nd isotopic compositions of kimberlites and associated rocks of the Siberian Craton.Doklady Earth Sciences, Vol. 413, 3, pp. 557-560.RussiaGeochronology
DS1985-0381
1985
Lapin, A.P.Lapin, A.P.Significance of Limited Miscibility in Silicate Carbonate Melts in the Petrology and Genesis of Carbonatites.International Geology Review, Vol. 26, No. 7, JULY PP. 779-794.RussiaPetrology
DS1980-0208
1980
Lapin, A.V.Lapin, A.V.Carbonatites of Explosive and Dike Facies; the Classification of Geologic Facies of Carbonatites.Geol. Rud. Mestorozhd., Vol. 22, No. 3, PP. 15-33.RussiaBlank
DS1980-0209
1980
Lapin, A.V.Lapin, A.V., Kharkiv, A.D.Geochemistry of Ultramafic Ilmenite Phlogopite Inclusions In Kimberlite and the Effect of Fluids on Differentiation of The Mantle.Doklady Academy of Science USSR, Earth Science Section., Vol. 255, PP. 234-236.RussiaGeochemistry, Petrography
DS1982-0358
1982
Lapin, A.V.Lapin, A.V.Carbonatite Differentiation ProcessesInternational Geology Review, Vol. 24, No. 9, PP. 1079-1089.RussiaClassification, Genesis
DS1984-0443
1984
Lapin, A.V.Lapin, A.V., Marshintsev, V.K.Carbonatites and Kimberlitic Carbonatites.(russian)Geol. Rudn. Mestorozh., (RUS), Vol. 26, No.3, pp. 28-42RussiaCarbonatite, Genesis
DS1986-0481
1986
Lapin, A.V.Lapin, A.V.The relationships between carbonatites and kimberlites and some problems of deep seated magma formationInternational Geology Review, Vol. 28, No. 8, August pp. 955-964RussiaCarbonatite, Kimberlites
DS1986-0482
1986
Lapin, A.V.Lapin, A.V.Relationship between kimberlites and carbonatites and some problems of deep magma genesis.(Russian)Izv. Akad. Nauk SSSR, Ser. Geol., (Russian), Vol. 1986, No. 12, pp. 36-46RussiaCarbonatite-kimberlite, Genesis
DS1986-0483
1986
Lapin, A.V.Lapin, A.V., Gushchin, V.N., Lugovaya, I.P.Isotopic interaction of carbonatites and metamorphosed carbonatite sedimentary rocks.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, pp. 979-986RussiaCarbonatite, Geochronology
DS1987-0394
1987
Lapin, A.V.Lapin, A.V.Typomorphism and genesis of strontio- and bariopyrochlores.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 296, No. 6, pp. 1453-1457RussiaBlank
DS1987-0395
1987
Lapin, A.V.Lapin, A.V., Gushin, V.N., Lougovaya, I.P.Isotopic interactions of carbonatites and carbonate metasedimentsGeochemistry International, Vol. 24, No. 2, pp. 73-80RussiaCarbonatite, Isotope
DS1987-0396
1987
Lapin, A.V.Lapin, A.V., Ploshko, V.V., Malyshev, A.A.Carbonatites of the Tatar deep seated fault zone on the Eniseiridge.(Russian)Geol. Rudn. Mestorozd., (Russian), Vol. 29, No. 1, pp. 30-45RussiaCarbonatite
DS1988-0376
1988
Lapin, A.V.Kravchenko, S.M., Bagdasarov, Yu.A., Lapin, A.V.Geological and mineral genetic new dat a on carbonatite formations.(Russian)Geologii i Geofiziki, (Russian), No. 11, PP. 22-31RussiaCarbonatite
DS1988-0401
1988
Lapin, A.V.Lapin, A.V., Malyshev, A.A., Ploshko, V.V., Cherepivskaya, G.Ye.Strontiopyrochlore from lateritic weathered mantle of carbonatiteDoklady Academy of Science USSR, Earth Science Section, Vol. 290, No. 1-6, March pp. 188-192RussiaSupergene alteration, analyses, Carbonatite
DS1988-0402
1988
Lapin, A.V.Lapin, A.V., Ploshko, V.V.Rock association and morphological types of carbonatite and their geotectonic environmentsInternational Geology Review, Vol. 30, No. 4, pp. 390-396RussiaCarbonatite
DS1990-0904
1990
Lapin, A.V.Lapin, A.V.On the composition and ore contents of the products of oxidation and reduction stages of carbonatite erosion.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 314, No. 4, pp. 922-925RussiaCarbonatite, Weathering
DS1992-0907
1992
Lapin, A.V.Lapin, A.V.Carbonatite weathering crusts: geochemical types and mineralizationGeochemistry International, Vol. 29, No. 7, pp. 72-83RussiaCarbonatite, Weathering
DS1992-0908
1992
Lapin, A.V.Lapin, A.V.On the composition and ore potential of the products of oxidizing and reducing stages in the weathering of carbonatitesDoklady Academy of Sciences USSR, Earth Science Section, Vol. 314, No. 1-6, July 1992, pp. 72-75RussiaCarbonatite, Weathering
DS1994-0985
1994
Lapin, A.V.Lapin, A.V.Churchite from lateritic weathered mantles on carbonatites and the behaviour of rare earths.Doklady Academy of Sciences USSR, Vol. 327, Oct. pp. 135-139.RussiaCarbonatite
DS1994-0986
1994
Lapin, A.V.Lapin, A.V.The rare earth elements in carbonatite weathering crusts: distribution, fractionation and mineral forms.Geochemistry International, Vol. 31, No. 10, pp. 34-49.RussiaCarbonatite, Weathering crust
DS1995-1057
1995
Lapin, A.V.Lapin, A.V.The geological setting and genesis of high grade complex rare metal ores Of the Tomtor deposit.Geology of Ore Deposits, Vol. 37, No. 1, Jan-Feb. pp. 17-31.Russia, SiberiaCarbonatite
DS1996-0806
1996
Lapin, A.V.Lapin, A.V.Classification and prediction of ore deposits of carbonatite weatheringcrusts.Geology of Ore Deposits, Vol. 38, No. 2, pp. 151-162.BrazilCarbonatite, NiobiuM., Deposit -Araxa
DS1996-0807
1996
Lapin, A.V.Lapin, A.V.Differential mobility of components in the Supergene zone as main factor information of carbonatite -Geochemistry International, Vol. 33, No. 6, pp. 1-18.RussiaCarbonatite, weathering, Deposit -Belozima, Tatarskoye, Chuktukon, Arasha, Tomto
DS200412-1085
2003
Lapin, A.V.Lapin, A.V., Kharkiv, A.D.Majhgawanites as a special petrochemical type of Diamondiferous igneous rocks.Geochemistry International, Vol. 41, 11, pp. 1081-89.IndiaGeochemistry
DS200612-0764
2005
Lapin, A.V.Lapin, A.V., Divaev, F.K., Kostiysyn, Yu.A.Petrochemical interpretation of carbonatite-like rocks from the Chagatai Complex of the Tien Shan with appllication to the problem of diamond potential.Petrology, Vol. 13, 5, pp. 499-510.Russia, AsiaCarbonatite-kimberlite rocks
DS200612-0765
2006
Lapin, A.V.Lapin, A.V., Verichev, E.M.Kimberlites and related rocks of the Arkhangel'sk Diamondiferous province and adjacent areas: a comparative petrogeochemical analysis.Geochemistry International, Vol. 44, 8, pp. 771-790.Russia, Archangel, Kola PeninsulaPetrology - review
DS200812-0632
2007
Lapin, A.V.Lapin, A.V., Tolstov, A.V., Vasilenko, V.B.Petrochemical characteristics of the kimberlites in the Middle Markha region with application to the problem of the geochemical heterogeneity of kimberlites.Geochemistry International, Vol. 45, 12, Dec. pp. 1197-1209.Russia, YakutiaGeochemistry - comparison Zolotitsa and Grib
DS200912-0425
2009
Lapin, A.V.Lapin, A.V., Belov, S.V.Models of diamond generation in different geodynamic environments.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractGlobalGeodynamics
DS200912-0426
2009
Lapin, A.V.Lapin, A.V., Tolstov, A.V.Geochemical types of kimberlites and their mantle sources.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, Kola Peninsula, ArchangelDeposits
DS201212-0396
2012
Lapin, A.V.Lapin, A.V., Gusev, G.S.Kimberlitic and non-kimberlitic diamond potential of igneous and metamorphic rocks.Geokart GEOS, Moscow, 448p. In RUSSIANMantleDiamond genesis
DS201807-1520
2018
Lapin, A.V.Nosova, A.A., Sazonova, L.V., Kargin, A.V., Smirnova, M.D., Lapin, A.V., Shcherbakov, V.D.Olivine in ultramafic lamprophyres: chemistry, crystallisation, and melt sources of Siberian pre and post trap aillikites. IlbokichContributions to Mineralogy and Petrology, 10.1007/ s00410-018- 1480-3, 27p.Russia, Siberiakimberlite

Abstract: We studied olivines from the Devonian pre-trap (the Ilbokich occurrence) and the Triassic post-trap (the Chadobets occurrence) carbonate-rich ultramafic lamprophyres (UMLs) in the southwestern portion of the Siberian craton. On the basis of detailed investigations of major, minor, and trace-element distributions, we have reconstructed the main processes that control the origins of these olivines. These include fractional crystallisation from melt, assimilation, and fractional crystallisation processes with orthopyroxene assimilation, melt-reaction diffusive re-equilibration, alkali enrichment, and CO2 degassing of the melt. Furthermore, we inferred the composition of the sources of the primary UML melt and their possible correlations with proto-kimberlitic melts, as well as the influence of the Triassic Siberian plume on the composition of the lithospheric mantle. The main differences between olivines from the Ilbokich and the Chadobets aillikites were that the olivines from the former had more magnesium-rich cores (Mg# = 89.2 ± 0.2), had Mg- and Cr-rich transition zones (Mg# = 89.7 ± 0.2 and 300-500 ppm Cr), had lower Ni (up to 3100 ppm) and Li (1.4-1.5 ppm), and had higher B (0.8-2.6 ppm) contents, all at higher Fo values (90-86), relative to the olivines from the latter (Mg# = 88-75; 200-300 ppm Cr; up to 3400 ppm Ni; 1.4-2.4 ppm Li; 0.4-2.2 ppm B). The Siberian aillikite sources contained a significant amount of metasomatic material. Phlogopite-rich MARID-type veins provided the likely metasomatic component in the pre-trap Devonian Ilbokich aillikite source, whereas the Triassic Chadobets aillikitic post-trap melts were derived from a source with a significant carbonate component. A comparison of UML olivines with olivines from the pre-trap and post-trap Siberian kimberlites shows a striking similarity. This suggests that the carbonate component in the aillikitic source could have been produced by evolved kimberlite melts. The differences in the lithospheric metasomatic component that contributed to pre-trap and post-trap aillikitic melts can be interpreted as reflections of the thermal impact of the Siberian Traps, which reduced phlogopite-bearing metasomes within the southwestern Siberian sub-continental lithospheric mantle.
DS1989-0853
1989
Lapin, A.V. 1989.Lapin, A.V. 1989.Types of ore deposits in weathering crusts of carbonatites.(Russian)Geol. Rudn. Mestorozhd., (Russian), Vol. 31, No. 4, pp. 76-87RussiaCarbonatite, Weathering-laterites
DS1996-0547
1996
LapinaGorshkov, A.I., Seliverstov, V.A., Sivstov, A.V., LapinaThe first discovery of native aluminum in carbonadoGeology of ore deposits, Vol. 38, No. 4, pp. 341-343.RussiaCarbonado, Kedrovka River
DS1998-1547
1998
Lapina, M.I.Vinokurov, S.F., Gorshkov, A.I., Lapina, M.I.Diamonds from kimberlite Diatreme 50, Liaoning Province, China:microtextural, mineralogical, geneticGeochemistry International, Vol. 36, No. 8, Aug. 1, pp. 676-683.ChinaTextures, petrology, Deposit - Diatreme 50
DS200412-0740
2003
Lapina, V.A.Gubarevich, A.V., Akhremkova, G.S., Lapina, V.A.Properties of the surface of ultrafine diamonds.Russian Journal of Physical Chemistry, Vol. 77, 11, pp. 1832-36. Ingenta 1035296891TechnologyDiamond morphology
DS200512-0942
2005
Lapke, C.Schmitt, R.T., Lapke, C., Lingemann, C.M., Siebenschock, M., Stoffler, D.Distribution and origin of impact diamonds in the Ries Carter, Germany.Geological Society of America, Special Paper, No. 384, pp. 299-314.Europe, GermanyMeteorite
DS2003-1178
2003
LapointeRolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., LapointeHeat flow in the western Superior province of the Canadian ShieldJournal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003GLO17386Ontario, Manitoba, SaskatchewanGeothermometry
DS1991-0090
1991
Lapointe, B.Bedard, L.P., Lapointe, B.Global warming: natural or anthropogenicGeoscience Canada, Vol. 18, No. 3, p. 98 onlyGlobalGlobal warming, Overview -climates
DS1994-0987
1994
Lapointe, B.Lapointe, B.L'exploration au Saguenay-Lac Saint Jean: bilan et perspectives.(in French)Seventh Colloque Annuel en Ressources Minerales, Universite du Quebec a, p. 13. abstract in FrenchQuebecBlank
DS1984-0359
1984
Lapointe, P.Hogarth, D.D., Lapointe, P.Amphibole and Pyroxene Development in Fenite from Cantley, Quebec.Canadian Mineralogist., Vol. 22, PP. 281-295.Canada, QuebecRelated Rocks, Carbonatite
DS200412-1682
2003
Lapointe, R.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., Carbonne, C., Lapointe, R.Surface heat flow, crustal temperatures and mantle heat flow in the Proterozoic Trans Hudson Orogen, Canadian Shield.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001 JB000698Canada, OntarioGeothermometry
DS200412-1683
2003
Lapointe, R.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., Lapointe, R.Heat flow in the western Superior province of the Canadian Shield.Journal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003 GLO17386Canada, Ontario, Manitoba, SaskatchewanGeothermometry
DS200512-0686
2005
Lapointe, R.Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., Fowler, C.M., Bienfait, G., Carbonne, C., Lapointe, R.Heat flow, thermal regime, and elastic thickness of the lithosphere in the Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 517-532.Canada, Northwest TerritoriesGeothermometry
DS200412-1249
2004
Laporte, D.Maumus, J., Laporte, D., Schiano, P.Dihedral angle measurements and infiltration property of SIO2 rich melts in mantle peridotite assemblages.Contributions to Mineralogy and Petrology, Vol. 148, 1, pp. 1-12.MantleMineralogy - peridotites
DS201012-0611
2010
Laporte, D.Rapp, R.P., Norman, M.D., Laporte, D., Yaxley, G.M., Martin, H., Foley, S.F.Continent formation in the Archean and chemical evolution of the cratonic lithosphere: melt rock reaction experiments at 3-4 GPa and petrogenesisJournal of Petrology, Vol. 51, 6, pp. 1237-1266.MantleSanukitoids
DS201212-0394
2012
Laporte, D.Lambart, S., Laporte, D., Provost, A., Schinao, P.Fate of pyroxenite derived melts in the periodotitic mantle: thermodynamic and experimental constraints.Journal of Petrology, Vol 53, 3, pp. 451-476.MantlePeridotite
DS201212-0445
2012
Laporte, D.Martin, A.M., Laporte, D., Koga, K.T., Kawamoto, T., Hammouda, T.Experimental study of the stability of a dolomite + coesite assemblage in contact with peridotite: implications for sediment-mantle interaction and diamond formation during subduction.Journal of Petrology, Vol. 53, 2, pp. 391-417.TechnologyUHP, diamond genesis
DS201212-0446
2012
Laporte, D.Martin, A.M., Laporte, D., Koga, K.T., Kawamoto, T., Hammouda, T.Experimental stidy of the stability of a dolomite + coesite assembalge in contact with peridotite: implications for sediment-mantle interaction and diamond formation during subduction.Journal of Petrology, Vol. 53, 2, pp. 391-417.MantleSubduction
DS201312-0169
2013
Laporte, D.Condamine, P., Medard, E., Laporte, D., Nauret, F.Experimental melting of phlogopite peridotite at 1 Gpa - implications for potassic magmatism.Goldschmidt 2013, AbstractMantleSubduction
DS201412-0498
2014
Laporte, D.Laporte, D., Lambart, S., Schiano, P., Ottolini, L.Experimental derivation of nepheline syenite and phonolite liquids by partial melting of upper mantle peridotites.Earth and Planetary Science Letters, Vol. 404, pp. 319-331.MantleMelting
DS201606-1077
2016
Laporte, D.Baasner, A., Medard, E., Laporte, D., Hoffer, G.Partial melting of garnet lherzolite with water and carbon dioxide at 3 Gpa using a new melt extraction technique: implications for intraplate magmatism.Contributions to Mineralogy and Petrology, Vol. 171, 45p.MantleMagmatism

Abstract: The origin and source rocks of alkali-rich and SiO2-undersatured magmas in the Earth’s upper mantle are still under debate. The garnet signature in rare earth element patterns of such magmas suggests a garnet-bearing source rock, which could be garnet lherzolite or garnet pyroxenite. Partial melting experiments were performed at 2.8 GPa and 1345-1445 °C in a piston-cylinder using mixtures of natural lherzolite with either 0.4 wt% H2O and 0.4 wt% CO2 or 0.7 wt% H2O and 0.7 wt% CO2. Different designs of AuPd capsules were used for melt extraction. The most successful design included a pentagonally shaped disc placed in the top part of the capsule for sufficient melt extraction. The degrees of partial melting range from 0.2 to 0.04 and decrease with decreasing temperature and volatile content. All samples contain olivine and orthopyroxene. The amounts of garnet and clinopyroxene decrease with increasing degree of partial melting until both minerals disappear from the residue. Depending on the capsule design, the melts quenched to a mixture of quench crystals and residual glass or to glass, allowing measurement of the volatile concentrations by Raman spectroscopy. The compositions of the partial melts range from basalts through picrobasalts to foidites. Compared to literature data for melting of dry lherzolites, the presence of H2O and CO2 reduces the SiO2 concentration and increases the MgO concentration of partial melts, but it has no observable effect on the enrichment of Na2O in the partial melts. The partial melts have compositions similar to natural melilitites from intraplate settings, which shows that SiO2-undersaturated intraplate magmas can be generated by melting of garnet lherzolite in the Earth’s upper mantle in the presence of H2O and CO2.
DS201912-2798
2019
Laporte, D.Laumonier, M., Laporte, D., Faure, F., Provost, A., Schiano, P., Ito, K.An experimental study of dissolution and precipitation of forsterite in a thermal gradient: implications for cellular growth of olivine phenocrysts in basalt and melt inclusion formation.Contributions to Mineralogy and Petrology, Vol. 174, 21p. PdfMantlebasanite

Abstract: The morphology of crystals in magmas strongly depends on the temperature regime of the system, in particular the degree of undercooling and the cooling rate. To simulate low degrees of undercooling, we developed a new experimental setup based on thermal migration, in which large cylinders of forsterite (single crystals) immersed in haplobasaltic melt were subjected to a temperature gradient. As forsterite solubility is sensitive to temperature, the forsterite on the high-temperature side undergoes dissolution and the dissolved components are transported toward the low-temperature side where a layer of newly grown forsterite forms (up to 340 µm thick after 101 h). A striking feature is that the precipitation process does not produce a planar front of forsterite advancing at the expense of liquid: the growth front shows a fingered outline in planar section, with solid lobes separated by glass tubes that are perpendicular to the growth front. We ascribe this texture to cellular growth, a type of growth that had not been experimentally produced so far in silicate systems. We find that the development of cellular growth requires low degrees of undercooling (a few °C) and large crystal-liquid interfaces (~?1 mm across or more), and that it occurs at a growth rate of the order of 10-9 m/s. We found natural occurrences of cellular growth on the rims of olivines from basanites, but otherwise cellular textures are poorly documented in natural volcanic rocks. Melt inclusions were produced in our experiments, showing that they can form in olivine at relatively slow rates of growth (10-9 m/s or lower).
DS1995-1058
1995
laporte, N.laporte, N., Lopez-Baeza, E., Moreno, J.F.Mapping the dense humid forest of Cameroon and Zaire using AVHRR satellitedataInternational Journal of Remote Sensing, Vol. 16, No. 6, April pp. 1127-1146Democratic Republic of CongoRemote sensing
DS200412-0884
2003
Lappegard, G.Iverson, N.R., Cohen, D., Hooyer, T.S., Fischer, U.H., Jackson, M., Moore, P.L., Lappegard, G., Kohler, J.Effects of basal debris on glacier flow.Science, No. 5629, July 4, pp. 81-83.TechnologyGeomorphology
DS1983-0387
1983
Lappin, A.V.Lappin, A.V., Vartiainen, H.Orbicular and Spherulitic Carbonatites from Sokli and Vuorijarvi.Lithos, Vol. 16, No. 1, PP. 53-60.GlobalMorphology, Fractionation, Silicates
DS1960-0260
1962
Lappin, M.A.Lappin, M.A.The Eclogites, Dunites and Anorthosites of the Selje and Almklovdalen Districts, Nordfiord, Southwestern Norway.Ph.d. Thesis, University Durham., Norway, ScandinaviaPetrography, Metamorphic Tectonites
DS1960-0856
1967
Lappin, M.A.Lappin, M.A.Structural and Petrofabric Studies of the Dunites of the Almklovdalen Nordfiord, Norway.Wiley Interscience., PP. 183-191.Norway, ScandinaviaPetrography
DS1970-0745
1973
Lappin, M.A.Lappin, M.A., Dawson, J.B.The Chemistry and Mineralogy of Two Eclogites from the Roberts Victor Pipe, Orange Free State.1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 195-198.South AfricaMineral Chemistry
DS1975-0122
1975
Lappin, M.A.Lappin, M.A., Dawson, J.B.Two Roberts Victor Cumulate Eclogites and Their Re-equilibriation.Physics and Chemistry of the Earth., Vol. 9, PP. 351-366.South AfricaMineral Chemistry
DS1975-0792
1978
Lappin, M.A.Lappin, M.A.The Evolution of a Grospydite from the Roberts Victor MineContributions to Mineralogy and Petrology, Vol. 66, PP. 229-241.South AfricaPetrography
DS1975-0793
1978
Lappin, M.A.Lappin, M.A., Smith, D.C.Mantle Equilibrated Orthopyroxene Eclogite Pods Form the Basal Gneisses in the Selje District, Western Norway.Journal of Petrology, Vol. 19, No. 3, PP. 530-584.Norway, ScandinaviaPetrography, Petrogenesis
DS1989-1412
1989
Lappin, M.A.Smith, D.C., Lappin, M.A.Coesite in the Straumen kyanite -eclogite pod, NorwayTerra Nova, Vol. 1, No. 1, pp. 47-56NorwayCoesite background, Eclogite
DS2002-0428
2002
Laptev, A.I.Elyutin, A.V., Ermolaev, A.A., Laptev, A.I., Manukhin, A.V.Effect of boron on the thermal stability of polycrystalline carbonado diamondsDoklady Physics, (language not known), Vol. 47, 9, pp. 651-3.GlobalCarbonados
DS1988-0403
1988
Laptev, V.A.Laptev, V.A., Pomchalov, A.V., Samoilovich, M.I.Diamond crystallization characteristics in a system consisting of a meta land difficulty graphitizable carbonaceous substances. (Russian)Sverkhtverd. Mater., (Russian), No. 4, pp. 13-17RussiaDiamond morphology
DS1988-0608
1988
Laptev, V.A.Samoylovich, M.I., Laptev, V.A.The deformational interactions of impurities and structural defects within the crystallattice of diamond.(Russian)Izv. Akad. Nauk SSSR, (Russian), Vol. 24, No. 8, pp. 1379-1381RussiaDiamond morphology, Diamond crystallography
DS200812-0746
2008
Laptsevich, A.G.Mikhaliov, N.D., Vladykin, N.V., Laptsevich, A.G.Geochemical features of alkali rocks of Paleozoic magmatism of Belarus.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 169-180.Russia, BelarusAlkaline rocks, magmatism
DS201112-0674
2010
Laptsevich, A.G.Mikhailov, N.D., Laptsevich, A.G., Vladykin, N.V.Alkali lamprophyres of the Paleozoic igneous complex of Belarus.Vladykin, N.V., Deep Seated Magmatism: its sources and plumes, pp. 187-199.RussiaLamprophyre
DS1988-0710
1988
Lapushkov, V.M.Tugovik, G.I., Kirasirova, V.I., Lapushkov, V.M.Physical properties of diamonds from eclogites of a plutonicmetamorphicregion.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 299, No. 2, pp. 442-444RussiaBlank
DS1998-1215
1998
LaputinaRass, I.T., Gerasimov, Laputina, IllupinDiamond occurrence in kimberlites dependent on melting depths and rates of cooling of parental mantle magmas.7th. Kimberlite Conference abstract, pp. 723-4.South Africa, Siberia, RussiaMagmatism, Deposit - Wesselton, Mir
DS1984-0646
1984
LAPUTINA, I.p.Seliverstov, V.A., Koloskovm a, V., LAPUTINA, I.p., et al.Ist Dat a on the Composition of Minerals of Deep Seated Inclusion in the Meimechites of Kamchatke.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 278, No. 4, PP. 949-952.RussiaBlank
DS1986-0662
1986
Laputina, I.P.Rass, I.T., Kravchenko, S.M., Laputina, I.P.Pyroxene zoning and the genesis of alkalic ultramafic rocksDoklady Academy of Science USSR, Earth Science Section, Vol. 280, No. 1-6, October pp. 117-122RussiaAlkaline rocks
DS1986-0719
1986
Laputina, I.P.Seliverstov, V.A., Koloskov, A.V., Laputina, I.P.First dat a on the composition of minerals of deep seated inclusions in meymechite from Kamchatka #2Doklady Academy of Science USSR, Earth Science Section, Vol. 278, No. 1-6, April, pp. 123-126RussiaMineralogy, Meymechite
DS1986-0720
1986
Laputina, I.P.Seliverstov, V.A., Koloskov, A.V., Laputina, I.P., et al.First dat a on the composition of minerals of deep seated inclusions in meymechite from Kamchatka #1Doklady Academy of Science USSR, Earth Science Section, Vol. 278, No. 10-6, pp. 127-130RussiaInclusions
DS1987-0155
1987
Laputina, I.P.Distler, V.V., Ilupin, I.P., Laputina, I.P.Sulfides of deep seated origin in kimberlites and some Aspects of coppernickel mineralizationInternational Geology Review, Vol. 29, No. 4, April pp. 456-464RussiaBlank
DS1996-1165
1996
Laputina, I.P.Rass, I.T., Laputina, I.P.Composition and zoning of accessory minerals in alkali ultrabasites as indicators of the composition magmas..Geochemistry International, Vol. 33, No. 2, Feb. 1, pp. 62-77RussiaLayered intrusion differentiation, Alkalic rocks, Pervoskite, Carbonatite
DS1997-0636
1997
Laputina, I.P.Kravechenko, S.M., Laputina, I.P., Krasilnikova, I.G.Geochemistry and genesis of rich scandium (Sc) rare earth elements (REE) yttrium niobium ores at the Tomtor deposit, northern Siberian PlatformGeochemistry International, Vol. 34, No. 10, pp. 847-63.Russia, SiberiaCarbonatite, Deposit - Tomtor
DS2002-0917
2002
Lar, U.A.Lar, U.A., Loubet, M.Major, trace element and isotope geochemistry of mafic ultramafic massifs emplaced within gneissic basement..Global Journal of Pure and Applied Geophysics, Vol.8, No.1, pp.75-88.VenezuelaMantle crust interactions, Geochemistry
DS1996-0808
1996
Laramie BountifulLaramie BountifulCompany opens commercial diamond mine... Kelsey LakeLaramie Bountiful, June 14, p. 1, 16.ColoradoNews item, Redaurum Limited
DS2000-0406
2000
Larbi, Y.Henry, P., Stevenson, R.K., Larbi, Y., Gariepy, C.neodymium isotopic evidence for Early to Late Archean (3.4-2.7Ga) crustal growth in Western Superior ProvinceTectonophysics, Vol. 322, No. 1-2, pp.135-51.OntarioGeochronology, Tectonics
DS2001-0718
2001
Larbi, Y.Madore, L., Larbi, Y.Regional structural character of the northeastern Ungava Peninsula: connection between Rae and SuperiorGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.93.abstract.Quebec, Ungava, LabradorTectonics - structure
DS200512-0845
2005
Larchenko, V.A.Perov, V.A., Bogomolov, E.S., Larchenko, V.A., Levskii, L.K., Minchenko, G.V., Sablukov, S.M., SZergeev, S.A., Stepanov, V.P.Rb Sr age of kimberlites of the Pionerskaya pipe, Arkangelsk Diamondiferous province.Doklady Earth Sciences, Vol. 400, 1, pp. 67-71.Russia, Kola Peninsula, ArchangelGeochronology -
DS200512-0847
2005
Larchenko, V.A.Pervov, V.A., Bogomolov, E.S., Larchenko, V.A., Levskii, L.K., Minchenko, Sabukov, Sergeev, StepanovRb Sr age of kimberlites of the Pionerskaya pipe, Arkangelsk Diamondiferous province.Doklady Earth Sciences, Vol. 400, 1, pp. 67-71.Russia, Archangel, Kola PeninsulaGeochronology
DS200612-1083
2006
Larchenko, V.A.Pervov, V.A., Larchenko, V.A., Minchenko, G.V., Stepanov, V.P., Bogomolov, E.S., Levskii, SergeevTiming and duration of kimberlitic magmatism in the Zimnii Bereg Diamondiferous province: evidence from Rb Sr age dat a on kimberlitic sills along the Mela River.Doklady Earth Sciences, Vol. 407, 2, Feb-Mar. pp. 304-307.RussiaGeochronology - Zimnii Bereg
DS200812-0123
2008
Larchenko, V.A.A.A.Bogatikov, O.A.A.A., Larchenko, V.A.A.A., Kononova, V.A.A.A., Nosova, A.A.A.A., Minchenko, G.A.V.A.New kimberlite bodies in the Zimnii Bereg field, Archangelsk district: petrography and prognostic estimates.Doklady Earth Sciences, Vol. 418, 1, pp. 68-72.Russia, Archangel, Kola PeninsulaDeposit - Zimnii Bereg
DS200912-0660
2009
Larchenko, V.A.A.A.Samsonov, A.A.V.A., Nosova, A.A.A.A., Tretyachenko, V.A.V.A., Larchenko, V.A.A.A., Larionova, Y.A.O.A.Collisional sutures in the early Precambrian crust as a factor for localization of Diamondiferous kimberlites in the northern east European platform.Doklady Earth Sciences, Vol. 425, 2, pp. 226-230.RussiaTectonics
DS201212-0595
2012
LardeauxRolland, Y., Lardeaux, J-M, Jolivet, L.Deciphering orogenic evolution.Journal of Geodynamics, Vol. 56-57, pp. 1-6.MantleTectonics
DS1997-0293
1997
Lardeaux, J.M.Duchene, S., Lardeaux, J.M., Albarade, F.Exhumation of eclogites: insights from depth time path analysisTectonophysics, Vol. 280, No. 1-2, Oct. 26, pp. 125-140.MantleEclogites, Subduction
DS1997-0909
1997
Lardeaux, J.M.Pili, E., Ricard, Y., Lardeaux, J.M.Lithospheric shear zones and mantle crust connectionsTectonophysics, Vol. 280, No. 1-2, Oct. 26, pp. 15-30.MantleLithosphere, Tectonics
DS2000-0621
2000
Lardeaux, J.M.Martelat, J.E., Lardeaux, J.M., Rakotondrazafy, R.Strain pattern and late Precambrian deformation history in southern MadagascarPrecambrian Research, Vol. 102, No. 1-2, July 1, pp. 1-20.MadagascarTectonics
DS2003-1067
2003
Lardeaux, J.M.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
Lardeaux, J.M.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
DS1991-1805
1991
Lardeaux, J-M.Villeurbanne, J.V., Von Roermund, H., Lardeaux, J-M.The clinopyroxene/plagioclase symplectite in retrograde eclogites: a potential geothermobarometerGeologische Rundschau, Vol. 80, No. 2, pp. 303-320GlobalEclogites, Petrology
DS201212-0596
2012
Lardeaux, J-M.Rolland, Y., Lardeaux, J-M., Jolivet, L.Deciphering orogenic evolution.Journal of Geodynamics, Vol. 56-57, pp. 1-6.MantleSubduction
DS202007-1162
2020
Lardeaux, J-M.Martelat, J-E., Cardon, H., Lardeaux, J-M., Nicollet, C., Schulmann, K., Pili, E.Geophysical evidence for large scale mullion type structures at the mantle crust interface in southern Madagascar: implications for Neoproterozoic orogeny.International Journal of Earth Science, Vol. 109, 4, pp. 1487-1500.Africa, Madagascartectonics

Abstract: This study uses gravimetric data integrated with recent seismic data published on south Madagascar to investigate geometry of crust-mantle interface. The regional tectonic framework of Madagascar is characterised by anastomosing network of up to 15-km-wide, 600-km-long and north-oriented high-strain zones, which originated during Neoproterozoic convergence. The studied Bouguer anomalies obtained from the International Gravimetric Bureau were high-pass filtered to emphasise short-wavelength gravimetric variations (shorter than 200 km). The Pan-African high-strain zones coincide with the positive gravimetric anomalies suggesting a link with deep seated high-density material. Considering the present-day thickness of the crust (35 km) and its seismic velocity record, the gravimetric anomalies can be visualised as narrow vertical tabular bodies located at the base of the Moho. Modelling further confirmed that such narrow vertical bodies could be stable over geologic time scale since these structures are relatively small (10 to 30 km wide). The vertical tabular bodies possibly reflect material transfer such as vertical motion of sub-crustal weak and possibly partially molten mantle along vertical deformation zones. It is proposed that these structures were initiated by folding of weak mantle-crust interface characterised by low-viscosity contrast between weak mantle and stronger granulitized lower crust during bulk pure shear-dominated horizontal shortening. It is proposed that the cuspate-lobate "mullion-type" geometry mimics rheological inversions of mafic and felsic rocks and shape of folds of variable scale observed in southern Madagascar. The formation of such mega-mullion structures is possibly an expression of "crème brulée" rheological model, where the deformation of the lithosphere is governed by stronger granulitic lower crust and weaker partially molten and/or hydrated mantle.
DS1995-1727
1995
Larehence, V.A.Shchukin, V.S., Sobolev, V., Larehence, V.A., Makhin, A.I.Geology of the diamond deposits in the Arkhangelsk region, RussiaSociety for Mining, Metallurgy and Exploration (SME) Meeting, Denver March 1995, abstractRussia, Commonwealth of Independent States (CIS), RussiaDiamond deposits
DS1998-1418
1998
Laresen, H.C.Storey, M., Duncan, R.A., Laresen, H.C.40 Ar-39 Ar geochronology of the West Greenland Tertiary volcanicprovince.Earth and Planetary Science Letters, Vol. 160, No. 3-4, Aug. 1, pp. 569-586.GreenlandGeochronology, Argon
DS2003-0724
2003
Laresen, H.C.Klausen, M.B., Laresen, H.C.East Greenland coast parallel dike swarm and its role in continental breakupGeological Society of America Special Paper, No. 362, chapter 9.GreenlandDike swarm, magmatism, Tectonics
DS200912-0732
2009
Laresen, L.M.Starkey, N.A., Stuart, F.M., Ellam, R.M., Fitton, J.G., Basu, S., Laresen, L.M.Helium isotopes in early Iceland plume picrites: constraints on the composition of high 3he/4He mantle.Earth and Planetary Science Letters, Vol. 277, 1-2, pp. 91-100.MantlePicrite
DS201802-0247
2017
Larianov, A.Koreshkova, M., Downes, H., Millar, I., Levsky, L., Larianov, A.Geochronology of metamorphic events in the lower crust of NW Russia: a xenolith Hf isotope study.Journal of Petrology, Vol. 58, 8, pp. 1567-1589.Russia, Kola Peninsulageochronology

Abstract: Hf isotope data for zircons and whole-rocks from lower crustal mafic granulite and pyroxenite xenoliths from NW Russia are presented together with the results of U-Pb zircon dating, Sm-Nd and Rb-Sr isotopic compositions of bulk-rocks and minerals, and trace element compositions of minerals. Most zircons preserve a record of only the youngest metamorphic events, but a few Grt-granulite xenoliths retain Archean magmatic zircons from their protolith. Metamorphic zircons have highly variable ?Hf(t) values from -25 to -4. The least radiogenic zircons were formed by recrystallization of primary magmatic Archean zircons. Zircons with the most radiogenic ?Hf grew before garnet or were contemporaneous with its formation. Zircons with ?Hf(t) from -15 to -9 formed by various mechanisms, including recrystallization of pre-existing metamorphic zircons, subsolidus growth in the presence of garnet and exsolution from rutile. They inherited their Hf isotopic composition from clinopyroxene, pargasite, rutile and earlier-formed zircon that had equilibrated with garnet. Subsolidus zircons were formed in response to a major change in mineral association (i.e. garnet- and zircon-producing reactions including partial melting). Recrystallized zircons date the onset of high-temperature conditions without a major change in mineral association. Age data for metamorphic zircons fall into five groups: >1•91 Ga, 1•81-1•86 Ga, 1•74-1•77 Ga, 1•64-1•67 Ga and <1•6 Ga. Most ages correlate with metamorphic events in the regional upper crust superimposed onto rocks of the Belomorian belt during formation of the Lapland Granulite Belt. Zircon formation and resetting at 1•64-1•67 Ga significantly postdates Lapland-Kola orogenic events and may relate to the onset of Mesoproterozoic rifting. The youngest ages (1•6-1•3 Ga) correspond to an event that affected only a few grains in some samples and can be explained by interaction with a localized fluid. The observed garnet-granulite associations were formed at 1•83 Ga in Arkhangelsk xenoliths and 1•74-1•76 Ga in most Kola xenoliths. By the end of the Lapland-Kola orogeny, the rocks were already assembled in the lower crust. However, no addition of juvenile material has been detected and preservation of pre-Lapland-Kola metamorphic zircon indicates that some xenoliths represent an older lower crust. Granulites, pyroxenites and Phl-rich rocks have a common metamorphic history since at least c. 1•75 Ga. At about 1•64 Ga metasomatic introduction of phlogopite took place; however, this was only one of several phlogopite-forming events in the lower crust.
DS1993-0881
1993
Larianov, N.P.Larianov, N.P.Equipment for gravity concentration of kimberlitesDiamonds of Yakutia, Russia, Extended Abstracts, Volume in English $ 115.00, pp. 171-172.Russia, YakutiaMineral processing, Mining -gravity concentration
DS200712-0596
2007
Larikova, T.Larikova, T.Geochemical characteristics of eclogites from the Eastern part of the Kokchetav Complex N. Kazakhstan.Plates, Plumes, and Paradigms, 1p. abstract p. A544.Russia, KazakhstanEclogite
DS200612-0189
2006
Larin, A.M.Buchko, I.V., Salnikova, E.B., Kotov, A.B., Larin, A.M., Velikoslavinskii, Sorokin, Sorokin, YakovlevaPaleoproterozoic gabbro anorthosites of the Selenga Superterrane, southern framing of the Siberian Craton.Doklady Earth Sciences, Vol. 407, 3, pp. 372-375.Russia, SiberiaTectonics
DS201712-2686
2017
Larin, A.M.Gladkochub, D.P., Donskaya, T.V., Sklyarov, E.V., Kotov, A.B., Vladykin, N.V., Pisarevsky, S.A., Larin, A.M., Salnikova, E.B., Saveleva, V.B., Sharygin, V.V., Starikova, A.E., Tolmacheva, E.V., Velikoslavinsky, S.D., Mazukabzov, A.M., Bazarova, E.P., KovaThe unique Katugin rare metal deposit ( southern Siberia): constraints on age and genesis.Ore Geology Reviews, in press available, 18p.Russia, Siberiadeposit - Katugin

Abstract: We report new geological, mineralogical, geochemical and geochronological data about the Katugin Ta-Nb-Y-Zr (REE) deposit, which is located in the Kalar Ridge of Eastern Siberia (the southern part of the Siberian Craton). All these data support a magmatic origin of the Katugin rare-metal deposit rather than the previously proposed metasomatic fault-related origin. Our research has proved the genetic relation between ores of the Katugin deposit and granites of the Katugin complex. We have studied granites of the eastern segment of the Eastern Katugin massif, including arfvedsonite, aegirine-arfvedsonite and aegirine granites. These granites belong to the peralkaline type. They are characterized by high alkali content (up to 11.8?wt% Na2O?+?K2O), extremely high iron content (FeO*/(FeO*?+?MgO)?=?0.96-1.00), very high content of most incompatible elements - Rb, Y, Zr, Hf, Ta, Nb, Th, U, REEs (except for Eu) and F, and low concentrations of CaO, MgO, P2O5, Ba, and Sr. They demonstrate negative and CHUR-close eNd(t) values of 0.0…-1.9. We suggest that basaltic magmas of OIB type (possibly with some the crustal contamination) represent a dominant part of the granitic source. Moreover, the fluorine-enriched fluid phases could provide an additional source of the fluorine. We conclude that most of the mineralization of the Katugin ore deposit occurred during the magmatic stage of the alkaline granitic source melt. The results of detailed mineralogical studies suggest three major types of ores in the Katugin deposit: Zr mineralization, Ta-Nb-REE mineralization and aluminum fluoride mineralization. Most of the ore minerals crystallized from the silicate melt during the magmatic stage. The accessory cryolites in granites crystallized from the magmatic silicate melt enriched in fluorine. However, cryolites in large veins and lens-like bodies crystallized in the latest stage from the fluorine enriched melt. The zircons from the ores in the aegirine-arfvedsonite granite have been dated at 2055?±?7?Ma. This age is close to the previously published 2066?±?6?Ma zircon age of the aegirine-arfvedsonite granites, suggesting that the formation of the Katugin rare-metal deposit is genetically related to the formation of peralkaline granites. We conclude that Katugin rare-metal granites are anorogenic. They can be related to a Paleoproterozoic (~2.05?Ga) mantle plume. As there is no evidence of the 2.05?Ga mantle plume in other areas of southern Siberia, we suggest that the Katugin mineralization occurred on the distant allochtonous terrane, which has been accreted to Siberian Craton later.
DS200912-0259
2009
Larin, N.V.Gorbatikov, A.V., Larin, N.V., Moiseev, E.I., Belyashov, A.V.The microseismic sounding method: application for the study of the buried diatreme structure.Doklady Earth Sciences, Vol. 428, 1, pp. 1222-1226.TechnologyGeophysics - seismics
DS200712-0397
2007
Larinov, A.Gusvea, N., Sergeev, S., Lobach-Zhuchenko, S., Larinov, A., Berezhnaya, N.Archean age of miaskite lamproites from the Panzero complex, Karelia.Doklady Earth Sciences, Vol. 413, 3, pp. 420-423.RussiaLamproite
DS200712-0398
2007
Larinov, A.Gusvea, N., Sergeev, S., Lobach-Zhuchenko, S., Larinov, A., Berezhnaya, N.Archean age of miaskite lamproites from the Panzero complex, Karelia.Doklady Earth Sciences, Vol. 413, 3, pp. 420-423.RussiaLamproite
DS200812-1209
2008
LarionovVernikovsky, V.A.A., Vernikovskaya, A.A.E.A., Salanikova, E.A.B.A., Berezhnaya, Larionov, Kotov, KovachLate Riphean alkaline magmatism in the western margin of the Siberian craton: a result of continental rifting or accretionary events?Doklady Earth Sciences, Vol. 419, 2, pp. 226-230.RussiaMagmatism
DS201112-0831
2010
LarionovProskurnin, V.F., Petrov, Bagdasarov, Rozinov, Tolmacheva, Larionov, Bilskaya, Gavrish, Mozoleva, PetrushkovOrigin of carbonatites of eastern Taimyr deduced from an isotopic and geochemical study of zircons.Geology of Ore Deposits, Vol. 52, 8, pp. 711-724.RussiaPetrology - carbonatites
DS200712-0568
2007
Larionov, A.Kontinen, A., Kapyaho, A., Huhma, H., Karhu, J., Matukov, D.I., Larionov, A., Sergeev, S.A.Nurmes paragneisses in eastern Finland, Karelian Craton: provenance, tectonic setting and implications for Neoarchean craton correlation.Precambrian Research, Vol. 152, 3-4, pp. 119-148.Europe, FinlandKarelian Craton
DS201801-0030
2017
Larionov, A.Koreshkova, M., Downes, H., Millar, I., Levsky, L., Larionov, A., Sergeev, S.Geochronology of metamorphic events in the lower crust beneath NW Russia: a xenolith Hf isotope study.Journal of Petrology, Vol. 58, 8, pp. 1567-1589.Russia, Kola Peninsulageochronology

Abstract: Hf isotope data for zircons and whole-rocks from lower crustal mafic granulite and pyroxenite xenoliths from NW Russia are presented together with the results of U-Pb zircon dating, Sm-Nd and Rb-Sr isotopic compositions of bulk-rocks and minerals, and trace element compositions of minerals. Most zircons preserve a record of only the youngest metamorphic events, but a few Grt-granulite xenoliths retain Archean magmatic zircons from their protolith. Metamorphic zircons have highly variable ?Hf(t) values from -25 to -4. The least radiogenic zircons were formed by recrystallization of primary magmatic Archean zircons. Zircons with the most radiogenic ?Hf grew before garnet or were contemporaneous with its formation. Zircons with ?Hf(t) from -15 to -9 formed by various mechanisms, including recrystallization of pre-existing metamorphic zircons, subsolidus growth in the presence of garnet and exsolution from rutile. They inherited their Hf isotopic composition from clinopyroxene, pargasite, rutile and earlier-formed zircon that had equilibrated with garnet. Subsolidus zircons were formed in response to a major change in mineral association (i.e. garnet- and zircon-producing reactions including partial melting). Recrystallized zircons date the onset of high-temperature conditions without a major change in mineral association. Age data for metamorphic zircons fall into five groups: >1•91 Ga, 1•81-1•86 Ga, 1•74-1•77 Ga, 1•64-1•67 Ga and <1•6 Ga. Most ages correlate with metamorphic events in the regional upper crust superimposed onto rocks of the Belomorian belt during formation of the Lapland Granulite Belt. Zircon formation and resetting at 1•64-1•67 Ga significantly postdates Lapland-Kola orogenic events and may relate to the onset of Mesoproterozoic rifting. The youngest ages (1•6-1•3 Ga) correspond to an event that affected only a few grains in some samples and can be explained by interaction with a localized fluid. The observed garnet-granulite associations were formed at 1•83 Ga in Arkhangelsk xenoliths and 1•74-1•76 Ga in most Kola xenoliths. By the end of the Lapland-Kola orogeny, the rocks were already assembled in the lower crust. However, no addition of juvenile material has been detected and preservation of pre-Lapland-Kola metamorphic zircon indicates that some xenoliths represent an older lower crust. Granulites, pyroxenites and Phl-rich rocks have a common metamorphic history since at least c. 1•75 Ga. At about 1•64 Ga metasomatic introduction of phlogopite took place; however, this was only one of several phlogopite-forming events in the lower crust.
DS200712-1119
2007
Larionov, A.N.Vetrin, V.R., Lepekhina, E.N., Larionov, A.N., Presnyakov, S.L., Serov, P.A.Initial subalkaline magmatism of the Neoarchean alkaline province of the Kola Peninsula.Doklady Earth Sciences, Vol. 415, No. 5, June-July pp. 714-717.Russia, Kola PeninsulaAlkalic
DS200912-0410
2009
Larionov, A.N.Koreshkova, M.Y., Downes, H., Nikitina, L.P., Vladykin, N.V., Larionov, A.N., Sergeev, S.A.Trace element and age characteristics of zircons in granulite xenoliths from the Udachnaya pipe, Siberia.Precambrian Research, Vol. 168, 3-4, pp. 197-212.Russia, YakutiaGeochronology
DS201212-0620
2012
Larionov, A.N.Samsonov, A.V., Tretyachenko, W., Nosova, A.A., Larionova, Yu.O., Lepekhina, E.N., Larionov, A.N., Ipatieva, I.S.Sutures in the early Precambrian crust as a factor responsible for localization of Diamondiferous kimberlites in the northern east European platform.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractRussia, Kola PeninsulaStructure
DS201312-0751
2012
Larionov, A.N.Romanova, I.V., Vernikovskaya, A.E., Vernikovsky, V.A., Matushkin, N.Yu., Larionov, A.N.Neoproterozoic alkaline magmatism and associated igneous rocks in the western framing of the Siberian craton: petrography, geochemistry, and geochronology.Russian Geology and Geophysics, Vol. 53, 11, pp. 1176-1196.RussiaMagmatism
DS202006-0921
2020
Larionov, A.N.Gusev, N.I., Sergeeva, L. Yu., Larionov, A.N., Skublov, S.G.Relics of the Eoarchean continental crust of the Anabar shield, Siberian Craton.Petrology, Vol. 28, 2, pp. 118-140.Russiadeposit - Daldyn

Abstract: In the northern part of the Anabar Shield, orthopyroxene plagiogneisses of the granulite Daldyn Group host lenses of mafic rocks surrounded by melanocratic rims. According to their chemical composition, the mafic rocks correspond to subalkaline gabbro, the plagiogneisses correspond to granodiorites contaminated with mafic material, and the rims are diorites. The orthopyroxene plagiogneisses of granodiorite composition have 147Sm/144Nd = 0.1097, eNd(?) = 1.6, TNd(DM) = 3.47 Ga and are metamorphosed anatectic granitoids with an age of 3.34 Ga. The mafic rocks have high Zr, Th, and Pb contents, are enriched in REE (SREE = 636 ppm), with a high degree of fractionation [(La/Yb)N = 17.73] and a well-defined Eu minimum (Eu/Eu* = 0.51), and have 147Sm/144Nd = 0.099, eNd(?) = 1.4 and TNd(DM) = 3.65 Ga. It is assumed that these rocks crystallized from melt derived from an enriched mantle (plume) source. Based on U-Pb (SHRIMP-II) dating of 50 zircon grains from the mafic rocks, a group of grains with concordant ages from 3567 to 1939 Ma was distinguished, along with a large number of discordant values. Multiple measurements in zircon grains with discordant age values make it possible to identify seven grains of Eoarchean age, with upper intercepts of the discordia corresponding to 3987 ± 71 to 3599 ± 33 Ma. The Lu-Hf systematics of 14 zircon grains is characterized by eHf(T) = +3.7 and by close values of THf(DM) = 3.95 and TCHf = 3.93 Ga (3.99 Ga for the oldest zircon). The Paleoarchean (3.57 Ga) zircons are characterized by negative values of eHf(T) = -5.3 and -6.8, THf(DM) = 3.92-3.98 Ga, and TCHf = 4.14-4.24 Ga, which indicate recycling of the preexisting Eoarchean and Hadean continental crust. The younger zircon (3287-2410 Ma) was also formed when the preexisting crust was recycled.
DS202008-1414
2020
Larionova, Y.Lebedeva, N., Nosova, A., Kargin, A., Larionova, Y., Sazonova, L., Tikhomirova, Y.Grib kimberlite peridotitic xenoliths: isotopic evidence of variable source of mantle metasomatism.Goldschmidt 2020, 1p. AbstractRussia, Kola Peninsuladeposit - Grib

Abstract: We present petrography and mineral chemistry for both phlogopite, from mantle-derived xenoliths (garnet peridotite, eclogite and clinopyroxene-phlogopite rocks) and for megacryst, macrocryst and groundmass flakes from the Grib kimberlite in the Arkhangelsk diamond province of Russia to provide new insights into multi-stage metasomatism in the subcratonic lithospheric mantle (SCLM) and the origin of phlogopite in kimberlite. Based on the analysed xenoliths, phlogopite is characterized by several generations. The first generation (Phl1) occurs as coarse, discrete grains within garnet peridotite and eclogite xenoliths and as a rock-forming mineral within clinopyroxene-phlogopite xenoliths. The second phlogopite generation (Phl2) occurs as rims and outer zones that surround the Phl1 grains and as fine flakes within kimberlite-related veinlets filled with carbonate, serpentine, chlorite and spinel. In garnet peridotite xenoliths, phlogopite occurs as overgrowths surrounding garnet porphyroblasts, within which phlogopite is associated with Cr-spinel and minor carbonate. In eclogite xenoliths, phlogopite occasionally associates with carbonate bearing veinlet networks. Phlogopite, from the kimberlite, occurs as megacrysts, macrocrysts, microcrysts and fine flakes in the groundmass and matrix of kimberlitic pyroclasts. Most phlogopite grains within the kimberlite are characterised by signs of deformation and form partly fragmented grains, which indicates that they are the disintegrated fragments of previously larger grains. Phl1, within the garnet peridotite and clinopyroxene-phlogopite xenoliths, is characterised by low Ti and Cr contents (TiO2 < 1 wt.%, Cr2O3 < 1 wt.% and Mg# = 100 × Mg/(Mg + Fe) > 92) typical of primary peridotite phlogopite in mantle peridotite xenoliths from global kimberlite occurrences. They formed during SCLM metasomatism that led to a transformation from garnet peridotite to clinopyroxene-phlogopite rocks and the crystallisation of phlogopite and high-Cr clinopyroxene megacrysts before the generation of host-kimberlite magmas. One of the possible processes to generate low-Ti-Cr phlogopite is via the replacement of garnet during its interaction with a metasomatic agent enriched in K and H2O. Rb-Sr isotopic data indicates that the metasomatic agent had a contribution of more radiogenic source than the host-kimberlite magma. Compared with peridotite xenoliths, eclogite xenoliths feature low-Ti phlogopites that are depleted in Cr2O3 despite a wider range of TiO2 concentrations. The presence of phlogopite in eclogite xenoliths indicates that metasomatic processes affected peridotite as well as eclogite within the SCLM beneath the Grib kimberlite. Phl2 has high Ti and Cr concentrations (TiO2 > 2 wt.%, Cr2O3 > 1 wt.% and Mg# = 100 × Mg/(Mg + Fe) < 92) and compositionally overlaps with phlogopite from polymict breccia xenoliths that occur in global kimberlite formations. These phlogopites are the product of kimberlitic magma and mantle rock interaction at mantle depths where Phl2 overgrew Phl1 grains or crystallized directly from stalled batches of kimberlitic magmas. Megacrysts, most macrocrysts and microcrysts are disintegrated phlogopite fragments from metasomatised peridotite and eclogite xenoliths. Fine phlogopite flakes within kimberlite groundmass represent mixing of high-Ti-Cr phlogopite antecrysts and high-Ti and low-Cr kimberlitic phlogopite with high Al and Ba contents that may have formed individual grains or overgrown antecrysts. Based on the results of this study, we propose a schematic model of SCLM metasomatism involving phlogopite crystallization, megacryst formation, and genesis of kimberlite magmas as recorded by the Grib pipe.
DS200912-0660
2009
Larionova, Y.A.O.A.Samsonov, A.A.V.A., Nosova, A.A.A.A., Tretyachenko, V.A.V.A., Larchenko, V.A.A.A., Larionova, Y.A.O.A.Collisional sutures in the early Precambrian crust as a factor for localization of Diamondiferous kimberlites in the northern east European platform.Doklady Earth Sciences, Vol. 425, 2, pp. 226-230.RussiaTectonics
DS201312-0775
2013
Larionova, Y.O.Samsonov, A.V., Griban, J.G., Larionova, Y.O., Nosova, A.A., Tretyachenko, V.V.Evolution of deep crustal roots of the Arhangelsk Diamondiferous province: evidences from crustal xenoliths and xenocrysts from Devonian kimberlite pipes.Goldschmidt 2013, 1p. AbstractRussia, Kola PeninsulaDeposit - Arkangel
DS201707-1344
2016
Larionova, Y.O.Larionova, Y.O., Sazonova, L.V., Lebedeva, N.M., Nosova, A., Tretyachenko, V.V., Travin, A.V., Kargin, A.V., Yudin, D.S.Kimberlite age in the Arkhangelsk province, Russia: isotopic geochronologic Rb-Sr and 40Ar/39Ar and mineralogical dat a on phlogopite.Petrology, Vol. 24, 6, pp. 562-593.Russiageochronology

Abstract: The paper reports detailed data on phlogopite from kimberlite of three facies types in the Arkhangelsk Diamondiferous Province (ADP): (i) massive magmatic kimberlite (Ermakovskaya-7 Pipe), (ii) transitional type between massive volcaniclastic and magmatic kimberlite (Grib Pipe), and (iii) volcanic kimberlite (Karpinskii-1 and Karpinskii-2 pipes). Kimberlite from the Ermakovskaya-7 Pipe contains only groundmass phlogopite. Kimberlite from the Grib Pipe contains a number of phlogopite populations: megacrysts, macrocrysts, matrix phlogopite, and this mineral in xenoliths. Phlogopite macrocrysts and matrix phlogopite define a single compositional trend reflecting the evolution of the kimberlite melt. The composition points of phlogopite from the xenoliths lie on a single crystallization trend, i.e., the mineral also crystallized from kimberlite melt, which likely actively metasomatized the host rocks from which the xenoliths were captured. Phlogopite from volcaniclastic kimberlite from the Karpinskii-1 and Karpinskii-2 pipes does not show either any clearly distinct petrographic setting or compositional differentiation. The kimberlite was dated by the Rb–Sr technique on phlogopite and additionally by the 40Ar/39Ar method. Because it is highly probable that phlogopite from all pipes crystallized from kimberlite melt, the crystallization age of the kimberlite can be defined as 376 ± 3 Ma for the Grib Pipe, 380 ± 2 Ma for the Karpinskii-1 pipe, 375 ± 2 Ma for the Karpinskii-2 Pipe, and 377 ± 0.4 Ma for the Ermakovskaya-7 Pipe. The age of the pipes coincides within the error and suggests that the melts of the pipes were emplaced almost simultaneously. Our geochronologic data on kimberlite emplacement in ADP lie within the range of 380 ± 2 to 375 ± Ma and coincide with most age values for Devonian alkaline–ultramafic complexes in the Kola Province: 379 ± 5 Ma; Arzamastsev and Wu, 2014). These data indicate that the kimberlite was formed during the early evolution of the Kola Province, when alkaline–ultramafic complexes (including those with carbonatite) were emplaced.
DS202005-0754
2020
Larionova, Y.O.Nosova, A.A., Kargin, A.V., Sazonova, L.V., Dubinina, E.O., Chugaev, A.V., Lebedeva, N.M., Yudin, D.S., Larionova, Y.O., Abersteiner, A., Gareev, B.I., Batalin, G.A.Sr-Nd-Pb isotopic systematic and geochronology of ultramafic alkaline magmatism of the southwestern margin of the Siberian craton: metasomatism of the sub-continental lithospheric mantle related to subduction and plume events.Lithos, Vol. 364-365, 21p. PdfRussia, Siberiadeposit - Ilbokich, Chadobets

Abstract: To provide new insights into the origin and evolution of ultramafic lamprophyres (UMLs) and their mantle source, we examined two UML (aillikite and damtjernite) occurrences of different ages in the western portion of the Siberian Craton (Ilbokich and Chadobets). New age, mineral and rock geochemistry, along with Sr-Nd-Pb-C-O isotope data was obtained. Our new 206Pb/238U perovskite age (399 ± 4 Ma) confirms the previously published Early Devonian age of the Ilbokich aillikite. RbSr isochron and 40Ar/39Ar dating yielded a Middle Triassic age (243 ± 3 Ma and 241 ± 1 Ma, respectively) for the Chadobets aillikites, indicating post-Trap emplacement of these rocks. Both UMLs are characterized by incompatible elements, including light rare earth element (LREE) enrichments (La is up to ×200 chondrite concentration), and strong fractionation of REEs ((La/Yb)n: 33-84). Despite the close geochemical affinity of both UMLs, the Nd isotopic compositions of aillikites, as well as the Pb isotopic composition of Chadobets and Ilbokich UMLs, do not overlap and are distinctly different from each other. The initial Sr and Nd isotopic compositions of the Ilbokich UMLs fall in within a narrow 87Sr/86Sr0 range (0.7032-0.7042) and eNd(T) (4.03-3.97). Chadobets UMLs have a similar Sr isotopic signature (87Sr/86Sr0: 0.7031-0.7043) and a more depleted Nd isotopic signature (eNd(T) 4.09-5.08). The initial Pb isotope compositions of the Chadobets UMLs are moderately radiogenic, ranging between 206Pb/204Pb = 18.4-19.0, 208Pb/204Pb = 38.3-38.8, and are characterized by a narrow 207Pb/204Pb ratio between 15.5 and 15.6. The Ilbokich Pb isotope compositions are less variable and range between 206Pb/204Pb = 18.0-18.4, 208Pb/204Pb = 37.8-38.4 and 207Pb/204Pb ratios between 15.5 and 15.6. The oxygen isotopic composition of carbonate from both UMLs is characterized by highly variable d18O values from +12.1 and up to +20.5‰ (SMOW). The isotopic composition of d13C values range from -1.3‰ to -7.1. Based on the minor impact of crustal contamination in both aillikites, it is inferred that their radiogenic isotope composition reflects a mantle source signature. The mantle source of the Chadobets aillikites is likely to include carbonatitic magma as a metasomatic agent. In contrast, phlogopite-rich metasomes within the lithospheric mantle could have contributed more significantly to the Ilbokich aillikites. These metasomes could be formed during the Caledonian orogeny, which did not only affect the southwestern boundary of the Siberian Craton, but also expanded to the craton interior. This study provides additional support for the evolution of the south-western portion of the Siberian SCLM, ranging from mantle containing phlogopite enrichment domains during the Early Devonian to hydrous-phase reduced mantle in the Triassic due to the thermal impact of the Siberian Traps.
DS202006-0943
2020
Larionova, Y.O.Novosa, A.A., Kargin, A.V., Sazonova, L.V., Dubinina, E.O., Chugaev, A.V., Lebedeva, N.M., Yudin, D.S., Larionova, Y.O., Abersteiner, A., Gareev, B.I., Batalin, G.A.Sr-N-Pb isotopic systematic and geochronology of ultramafic alkaline magmatism of the southwestern margin of the Siberian craton: metasomatism of the sub-continental lithospheric mantle related to subduction and plume events.Lithos, Vol. 364-365, 21p. PdfRussiaailikite, damjernite

Abstract: To provide new insights into the origin and evolution of ultramafic lamprophyres (UMLs) and their mantle source, we examined two UML (aillikite and damtjernite) occurrences of different ages in the western portion of the Siberian Craton (Ilbokich and Chadobets). New age, mineral and rock geochemistry, along with Sr-Nd-Pb-C-O isotope data was obtained. Our new 206Pb/238U perovskite age (399 ± 4 Ma) confirms the previously published Early Devonian age of the Ilbokich aillikite. RbSr isochron and 40Ar/39Ar dating yielded a Middle Triassic age (243 ± 3 Ma and 241 ± 1 Ma, respectively) for the Chadobets aillikites, indicating post-Trap emplacement of these rocks. Both UMLs are characterized by incompatible elements, including light rare earth element (LREE) enrichments (La is up to ×200 chondrite concentration), and strong fractionation of REEs ((La/Yb)n: 33-84). Despite the close geochemical affinity of both UMLs, the Nd isotopic compositions of aillikites, as well as the Pb isotopic composition of Chadobets and Ilbokich UMLs, do not overlap and are distinctly different from each other. The initial Sr and Nd isotopic compositions of the Ilbokich UMLs fall in within a narrow 87Sr/86Sr0 range (0.7032-0.7042) and eNd(T) (4.03-3.97). Chadobets UMLs have a similar Sr isotopic signature (87Sr/86Sr0: 0.7031-0.7043) and a more depleted Nd isotopic signature (eNd(T) 4.09-5.08). The initial Pb isotope compositions of the Chadobets UMLs are moderately radiogenic, ranging between 206Pb/204Pb = 18.4-19.0, 208Pb/204Pb = 38.3-38.8, and are characterized by a narrow 207Pb/204Pb ratio between 15.5 and 15.6. The Ilbokich Pb isotope compositions are less variable and range between 206Pb/204Pb = 18.0-18.4, 208Pb/204Pb = 37.8-38.4 and 207Pb/204Pb ratios between 15.5 and 15.6. The oxygen isotopic composition of carbonate from both UMLs is characterized by highly variable d18O values from +12.1 and up to +20.5‰ (SMOW). The isotopic composition of d13C values range from -1.3‰ to -7.1. Based on the minor impact of crustal contamination in both aillikites, it is inferred that their radiogenic isotope composition reflects a mantle source signature. The mantle source of the Chadobets aillikites is likely to include carbonatitic magma as a metasomatic agent. In contrast, phlogopite-rich metasomes within the lithospheric mantle could have contributed more significantly to the Ilbokich aillikites. These metasomes could be formed during the Caledonian orogeny, which did not only affect the southwestern boundary of the Siberian Craton, but also expanded to the craton interior. This study provides additional support for the evolution of the south-western portion of the Siberian SCLM, ranging from mantle containing phlogopite enrichment domains during the Early Devonian to hydrous-phase reduced mantle in the Triassic due to the thermal impact of the Siberian Traps.
DS202010-1856
2020
Larionova, Y.O.Lebedeva, N.M., Nosova, A.A., Kargin, A.V., Larionova, Y.O., Sazonova, L.V., Tikhomirova, Y.S.S-Nd-O isotopic evidence of variable sources of mantle metasomatism in the subcratonic lithospheric mantle beneath the Grib kimberlite, northwestern Russia.Lithos, in press available, 54p. PdfRussia, Kola Peninsuladeposit - Grib

Abstract: To provide new insights into the type and extent of mantle metasomatism in the subcratonic lithospheric mantle, we examined the Sr-Nd-O isotopic compositions of orthopyroxene, clinopyroxene, garnet, ilmenite and phlogopite from sheared garnet lherzolite, granular garnet harzburgites and lherzolites and clinopyroxene-phlogopite rocks from the Grib kimberlite in the Arkhangelsk diamond province in northwestern Russia. Clinopyroxene and orthopyroxene from sheared garnet lherzolite initially have a close value of 87Sr/86Sr(t) (~0.7034) and close weak positive eNd. Orthopyroxene and clinopyroxene are in oxygen isotope equilibrium with coexisting olivine. Clinopyroxene from a garnet harzburgite has a low 87Sr/86Sr(t) isotope ratio of 0.70266. Clinopyroxene from granular garnet lherzolites has a relatively narrow variation in 87Sr/86Sr(t) (0.70456-0.70582) and considerably larger variations in eNd (-4.3?-?+1.0) isotope ratios. Garnet displays elevated initial 87Sr/86Sr(t) values (0.70540-0.70633). Ilmenite shows a narrow range in 87Sr/86Sr(t) (0.70497-0.70522) coupled with eNd values of +0.4 and +3.5. These isotopic data suggest granular garnet lherzolite of mantle metasomatism took place during the interaction of kimberlite melts with SCLM that contained mica-amphibole-rutile-ilmenite-diopside (MARID)-type metasomes. Clinopyroxenes from clinopyroxene-phlogopite (phlogopite wehrlite) xenoliths display a broader range in 87Sr/86Sr(t) (0.70486-0.70813) that is significantly higher than the kimberlite values and a circa-chondritic eNd (-0.1 -?+1.3) with a restricted d18O range (5.11‰-5.33‰). More radiogenic Sr isotopic composition decoupled from Nd isotopes could have been induced by metasomatic melt/fluid related to a subducted material. The isotopic compositions of mantle minerals preserve Sr-Nd isotopic evidence of pre-kimberlite metasomatic events that were probably due to incomplete reequilibration with ultramafic carbonated melt. Based on mineral pairs Rb-Sr isochrons and a clinopyroxene-based Sm-Nd errochron, these mantle metasomatic events correspond to ~550-600?Ma and ~1200?Ma episodes of magmatic-thermal activity.
DS201412-0443
2014
Larionova, Yu.Kargin, A., Nosova, A., Larionova, Yu., Kononova, V., Borisovsky, S., Kovalchuk, E., Griboedova, I.Mesoproterozoic orangeites ( Kimberlites II) of west Karelia: mineralogy, geochemistry and Sr-Nd isotope composition.Petrology, Vol. 22, 2, pp. 151-183.RussiaOrangeites
DS201212-0620
2012
Larionova, Yu.O.Samsonov, A.V., Tretyachenko, W., Nosova, A.A., Larionova, Yu.O., Lepekhina, E.N., Larionov, A.N., Ipatieva, I.S.Sutures in the early Precambrian crust as a factor responsible for localization of Diamondiferous kimberlites in the northern east European platform.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractRussia, Kola PeninsulaStructure
DS201612-2315
2016
Larionova, Yu.O.Larionova, Yu.O., Sazonova, L.V., Lebedeva, N.M., Nosova, A.A., Tretyachenko, V.V., Travin, A.V., Kargin, A.V., Yudin, D.S.Kimberlite age in the Arkhangelsk province, Russia: isotopic geochronologic Rb-Sr and 40Ar/39Ar and mineralogical dat a on phlogopite.Petrology, Vol. 24, 6, pp. 562-593.Russia, Archangel, Kola PeninsulaDeposit - Ermakovskaya-7, Grib, Karpinski

Abstract: The paper reports detailed data on phlogopite from kimberlite of three facies types in the Arkhangelsk Diamondiferous Province (ADP): (i) massive magmatic kimberlite (Ermakovskaya-7 Pipe), (ii) transitional type between massive volcaniclastic and magmatic kimberlite (Grib Pipe), and (iii) volcanic kimberlite (Karpinskii-1 and Karpinskii-2 pipes). Kimberlite from the Ermakovskaya-7 Pipe contains only groundmass phlogopite. Kimberlite from the Grib Pipe contains a number of phlogopite populations: megacrysts, macrocrysts, matrix phlogopite, and this mineral in xenoliths. Phlogopite macrocrysts and matrix phlogopite define a single compositional trend reflecting the evolution of the kimberlite melt. The composition points of phlogopite from the xenoliths lie on a single crystallization trend, i.e., the mineral also crystallized from kimberlite melt, which likely actively metasomatized the host rocks from which the xenoliths were captured. Phlogopite from volcaniclastic kimberlite from the Karpinskii-1 and Karpinskii-2 pipes does not show either any clearly distinct petrographic setting or compositional differentiation. The kimberlite was dated by the Rb-Sr technique on phlogopite and additionally by the 40Ar/39Ar method. Because it is highly probable that phlogopite from all pipes crystallized from kimberlite melt, the crystallization age of the kimberlite can be defined as 376 ± 3 Ma for the Grib Pipe, 380 ± 2 Ma for the Karpinskii-1 pipe, 375 ± 2 Ma for the Karpinskii-2 Pipe, and 377 ± 0.4 Ma for the Ermakovskaya-7 Pipe. The age of the pipes coincides within the error and suggests that the melts of the pipes were emplaced almost simultaneously. Our geochronologic data on kimberlite emplacement in ADP lie within the range of 380 ± 2 to 375 ± Ma and coincide with most age values for Devonian alkaline-ultramafic complexes in the Kola Province: 379 ± 5 Ma; Arzamastsev and Wu, 2014). These data indicate that the kimberlite was formed during the early evolution of the Kola Province, when alkaline-ultramafic complexes (including those with carbonatite) were emplaced.
DS202010-1843
2020
Larionova, Yu.O.Erofeeva, K.G., Samsonov, A.V., Stepanova, A.V., Larionova, Yu.O., Dubinina, E.O., Egorova, S.V., Arzamastesev, A.A., Kovalchuk, E.V., Abramova, V.D.Olivine and clinopyroxene phenocrysts as a proxy for the origin and crustal evolution of primary mantle melts: a case study of 2.40 Ga mafic sills in the Kola-Norwegian Terrane, northern Fennoscandia.Petrology, Vol. 28, 4, pp. 338-356. pdfEurope, Norway, Kola Peninsulamelting

Abstract: New petrographic, geochemical, and isotopic (Sr, Nd, and d18?) data on olivine and pyroxene phenocrysts provide constraints on the composition and crustal evolution of primary melts of Paleoproterozoic (2.40 Ga) picrodoleritic sills in the northwest Kola province, Fennoscandian Shield. The picrodolerites form differentiated sills with S-shaped compositional profiles. Their chilled margins comprise porphyritic picrodolerite (upper margin) and olivine gabbronorite (bottom) with olivine and clinopyroxene phenocrysts. Analysis of the available data allows us to recognize three main stages in the crystallization of mineral assemblages. The central parts of large (up to 2 mm) olivine phenocrysts (Ol-1-C) crystallized at the early stage. This olivine (Mg# 85-92) is enriched in Ni (from 2845 to 3419 ppm), has stable Ni/Mg ratio, low Ti, Mn and Co concentrations, and contains tiny (up to 10 µm) diopside-spinel dendritic lamella that probably originated due to the exsolution from high Ca- and Cr- primary magmatic olivine. All these features of Ol-1-C are typical of olivine from primitive picritic and komatiitic magmas (De Hoog et al., 2010; Asafov et al., 2018). Ol-1-C contains large (up to 0.25 mm) crystalline inclusions of high-Al enstatite (Mg# 80-88) and clinopyroxene (Mg# 82-90), occasionally in association with Ti-pargasite and chromian spinel (60.4 wt.% Al2O3). These inclusions are regarded as microxenoliths of wall rock that were captured by primary melt at depths more than 30 km and preserved due to the conservation in magmatic olivine. The second stage was responsible for the crystallization of Ol-1 rim (Ol-1-R), small (up to 0.3 mm) olivine (Ol-2, Mg# 76-85) grains, and central parts of large (up to 1.5 mm) clinopyroxene (Cpx-C) phenocrysts in the mid-crustal transitional magma chamber (at a depth of 15-20 km) at 1160-1350°C. At the third stage, Cpx-C phenocrysts were overgrown by low-Mg rims (Mg# 70-72) similar in composition to the groundmass clinopyroxene from chilled picrodolerite and gabbro-dolerite in the central parts of the sills. This stage likely completed the evolution of picrodoleritic magma and occurred in the upper crust at a depth of about 5 km. All stages of picrodoleritic magma crystallization were accompanied by contamination. Primary melts were contaminated by upper mantle and/or lower crust as recognized from xenocrystic inclusions in Ol-1-C. The second contamination stage is supported by the negative values of eNd(2.40) = -1.1 in clinopyroxene phenocrysts. At the third stage, contamination likely occurred in the upper crust when ascending melts filled gentle fractures. This caused vertical whole-rock Nd heterogeneity in the sills (Erofeeva et al., 2019), and difference in Nd isotopic composition of clinopyroxene phenocrysts and doleritic groundmass. It was also recognized that residual evolved melts are enriched in radiogenic strontium but have neodymium isotopic composition similar to other samples. It could be explained by the interaction of the melts with fluid formed via decomposition of biotite from surrounding gneisses under the effect of high-temperature melts.
DS200612-0319
2006
Lariviere, J.M.Day, S.J.A., Lariviere, J.M., Friske, P.W.B., McNeil, R.J., McCurdy, M.W.National geochemical Reconnaissance: regional stream sediment and water data: Travaillant Lake area.. analytical, mineralogical kimberlite indicator dataGeological Survey of Canada Open File, 4951, 1 CD May 17, $ 9.10Canada, Northwest TerritoriesGeochemistry - NTS 106N part of 106O
DS1991-0953
1991
Larkin, B.J.Larkin, B.J.An ANSI C routine to determine if a point is within a specified convex polygon in logarithmic timeComputers and Geosciences, Vol. 17, No. 6, pp. 841-848GlobalComputers, Program -ANSI C -polygon
DS2002-0918
2002
Larkin, D.Larkin, D.The role of a professional institute in addressing the sustainability of human capital in minerals industry.Australian Institute of Mining and Metallurgy, No. 3/2002, pp.37-40.AustraliaEmployment trends, Sustainable development - trends
DS2001-0795
2001
Larkin, P.A.Moore, A.E., Larkin, P.A.Drainage evolution in south central Africa since the break up of GondwanaSouth African Journal of Geology, Vol. 104, pp. 47-68.South AfricaGeomorphology - Zambezi, Limpopo
DS1997-0650
1997
Larkin, S.P.Larkin, S.P., Levander, A. , Henstock, T.J.Is the MOHO flat? Seismic evidence for a rough crust-mantle interface beneath the north Basin -RangeGeology, Vol. 25, No. 5, May pp. 451-454United States, Basin and RangeGeophysics - seismics, Crust - mantle
DS2000-0656
2000
Larkina, V.I.Migulin, V.V., Larkina, V.I., Sergeeva, N.G., Senin, B.Reflection of geodynamic processes in characteristics of electromagnetic radiation above Baltic Shield...Doklady Academy of Sciences, Vol. 373, No. 5, June-July, pp.845-50.Russia, Baltic Shield, Barents-Kara regionTectonics, Geophysics
DS1989-1172
1989
Larochelle, A.Park, J.K., Norris, D.K., Larochelle, A.Paleomagnetism and the origin of the Mackenzie Arc of northwestern CanadaCanadian Journal of Earth Sciences, Vol. 26, pp. 2194-2203.British ColumbiaGeophysics - paleomagnetics
DS201607-1310
2016
LaRocque, A.Ou, C., Leblon, B., Zhang, Yu., LaRocque, A., Webster, K., McLaughlin, J.Modelling and mapping permafrost at high spatial resolution using Land sat and Radarsat images in northern Ontario: model calibration and regional mapping.International Journal of Remote Sensing, Vol. 37, 12, pp. 2727-2779.Canada, OntarioNews item - permafrost

Abstract: Permafrost is an important ground thermal condition that has significant biophysical and socio-economic impacts. In order to better understand the distribution and dynamics of permafrost, there is a need to map permafrost at high spatial resolution. This study is part of a research project that aims to model and map permafrost using remote sensing images and the Northern Ecosystem Soil Temperature (NEST) model in the central part of the Hudson Bay Lowland in northern Ontario, Canada. The study area is near the southern margin of permafrost region where permafrost exists only in isolated patches. In this study, we ran the NEST model from 1932 to 2012 using a climate data set compiled from station observations and grid data sources. The model outputs were then compared to field observations acquired during 2009 -2012 at seven peat monitoring stations and two flux towers, which represent three major types of peatland in the study area (bog, fen, and palsa). The simulated soil temperatures at various depths show good agreement with the observations, and the simulated latent and sensible heat fluxes and net radiation are similar to the observations at the two flux towers. The model accurately shows the existence of permafrost only at palsa sites. Based on the general range of climate and ground conditions in this area, sensitivity tests indicate that the modelled permafrost conditions are sensitive to leaf area index, air temperature, precipitation, and soil texture. Therefore, the NEST model is capable of simulating ground temperature and permafrost conditions in where permafrost occurs only sporadically. A companion paper (part 2) uses the model with Landsat and Radarsat imagery to map the distribution and dynamics of permafrost in this area.
DS1998-0829
1998
Larocque, A.C.L.Larocque, A.C.L., Rasmussen, P.E.An overview of trace metals in the environment, from mobilization toremediationEnviron. Geology, Vol. 33, No. 2-3, Feb. pp. 85-91GlobalGeochemistry - trace metals, Environment
DS2002-1094
2002
Larose, T.M.Morris, T.F., Pitre, S.A., Larose, T.M.Kimberlite and base metal exploration targets, derived from overburden heavy mineral dat a Schreiber area, northwestern Ontario.Ontario Geological Survey Open File, No. 6074, 113p.OntarioGeochemistry
DS200412-1371
2002
Larose, T.M.Morris, T.F., Pitre, S.A., Larose, T.M.Kimberlite and base metal exploration targets, derived from overburden heavy mineral dat a Schreiber area, northwestern Ontario.Ontario Geological Survey Open File, No. 6074, 113p.Canada, OntarioGeochemistry
DS201708-1701
2017
Laroulandie, C.Laroulandie, C.Barium and titanium enrichment of zoned phlogopite xenocrysts and phenocrysts in the Adamantin kimberlites, Quebec, Canada.11th. International Kimberlite Conference, PosterCanada, Quebecdeposit - Adamantin
DS202010-1862
2020
Larre, C.Morizet, Y., Larre, C., Di Carlo, I., Gaillard, F.High S and high CO2 contents in haplokimberlite: an experimental and Raman spectroscopic study.Mineralogy and Petrology, Vol. 114, pp. 363-373. pdfMantlemelting

Abstract: Sulfur is an important element present in natural kimberlites and along with CO2, S can play a role in the kimberlite degassing. We have investigated experimentally the change in S content and CO2 solubility in synthetic kimberlitic melts in response to a range of pressure (0.5 to 2.0 GPa) and temperature (1500 to 1525 °C). Several initial S concentrations were investigated ranging from 0 to 24000 ppm. The dissolved CO2 and S were determined by Raman spectroscopy and Electron Probe Micro-Analyses. Under the investigated oxidizing conditions (?FMQ?+?1), S is dissolved in the glass only as S6+ forming sulfate molecular groups (SO42-). The measured S concentration in the glasses increases from 2900 to 22000 ppm. These results suggest that the experimental conditions were below saturation with respect to S and that the S solubility is higher than 22000 ppm for kimberlitic melts; regardless of the experimental conditions considered here. CO2 is dissolved as CO32- molecular groups. The CO2 solubility ranges from 3.0 to 11.3 wt% between 0.5 and 2.0 GPa. CO2 solubility is not affected by the presence of S; which suggests that SO42- and CO32- clusters have two distinct molecular environments not interacting together. This result implies that both CO2 and S are efficiently transported by kimberlitic melt from the upper mantle towards the atmosphere.
DS1989-1053
1989
Larrere, M.Moretti, I., Larrere, M.LOCACE: computer aided construction of balanced geological crosssectionsGeobyte, Vol. 4, No. 5, pp. 16-24. Database #18196GlobalComputer, Program -LOCACE.
DS1995-0694
1995
Larroque, C.Guilhaumou, N., Larroque, C.Les circulations de fluides dans les prismes d'accretion: fluides fossile set fluides actuelsC.r. Academy Of Science Paris, Vol. 321, 11a, pp. 939-957GlobalGeodynamics, Paleomarkers
DS201801-0009
2017
Larrouturou, G.Coltice, N., Larrouturou, G., Debayle, E., Garnero, E.J.Interactions of scales of convection in the Earth's mantle.Tectonophysics, in press available, 9p.Mantleplate tectonics, geophysics - seismics

Abstract: The existence of undulations of the geoid, gravity and bathymetry in ocean basins, as well as anomalies in heat flow, point to the existence of small scale convection beneath tectonic plates. The instabilities that could develop at the base of the lithosphere are sufficiently small scale (< 500 km) that they remain mostly elusive from seismic detection. We take advantage of 3D spherical numerical geodynamic models displaying plate-like behavior to study the interaction between large-scale flow and small-scale convection. We find that finger-shaped instabilities develop at seafloor ages > 60 Ma. They form networks that are shaped by the plate evolution, slabs, plumes and the geometry of continental boundaries. Plumes impacting the boundary layer from below have a particular influence through rejuvenating the thermal lithosphere. They create a wake in which new instabilities form downstream. These wakes form channels that are about 1000 km wide, and thus are possibly detectable by seismic tomography. Beneath fast plates, cold sinking instabilities are tilted in the direction opposite to plate motion, while they sink vertically for slow plates. These instabilities are too small to be detected by usual seismic methods, since they are about 200 km in lateral scale. However, this preferred orientation of instabilities below fast plates could produce a pattern of large-scale azimuthal anisotropy consistent with both plate motions and the large scale organisation of azimuthal anisotropy obtained from recent surface wave models.
DS201901-0020
2018
Larrouturou, G.Coltice, N., Larrouturou, G., Debayle, E., Garnero, E.J.Interactions of scales of convection in the Earth's mantle.Tectonophysics, Vol. 746, pp. 669-677.Mantleconvection

Abstract: The existence of undulations of the geoid, gravity and bathymetry in ocean basins, as well as anomalies in heat flow, point to the existence of small scale convection beneath tectonic plates. The instabilities that could develop at the base of the lithosphere are sufficiently small scale (< 500 km) that they remain mostly elusive from seismic detection. We take advantage of 3D spherical numerical geodynamic models displaying plate-like behavior to study the interaction between large-scale flow and small-scale convection. We find that finger-shaped instabilities develop at seafloor ages > 60 Ma. They form networks that are shaped by the plate evolution, slabs, plumes and the geometry of continental boundaries. Plumes impacting the boundary layer from below have a particular influence through rejuvenating the thermal lithosphere. They create a wake in which new instabilities form downstream. These wakes form channels that are about 1000 km wide, and thus are possibly detectable by seismic tomography. Beneath fast plates, cold sinking instabilities are tilted in the direction opposite to plate motion, while they sink vertically for slow plates. These instabilities are too small to be detected by usual seismic methods, since they are about 200 km in lateral scale. However, this preferred orientation of instabilities below fast plates could produce a pattern of large-scale azimuthal anisotropy consistent with both plate motions and the large scale organisation of azimuthal anisotropy obtained from recent surface wave models.
DS201710-2257
2017
Larroza, F.A.Presser, J.L.B., Tondo, M.J., Dolsa, S.F., Rocca, M.C.L., Alonso, R.N., Benetiz, P., Larroza, F.A., Duarte, B.J.R., Cabral-Antunez, N.D.Brief comments on the impact metamorphism in Cerro Leon quartzites, western Paraguay. English abstract ** in PORTPyroclastic Flow, Vol. 7, 1,pp. 16-24.South America, Paraguayimpact diamonds

Abstract: The petrographic study of two samples (quartzite and impactite) of Cerro León, a mountain range located in the middle of very probable impact basins (Cerro Leon-1, 2, 3 and 4-department of Alto Paraguay, Western-Paraguay) indicated evidences of impact metamorphism: PDFs (Not decorated and decorated) and diaplectic glass. Associated with diaplectic glass, impact diamonds or diamond/lonsdaleite crystals (micro and small macros) were observed with a range of morphologies including isolated and mostly agglutinated crystal varieties. Impact diamonds estimated to have formed by carbonate impact metamorphism present in the sedimentary target-rock of the Silurian/Devonian age. The identification of elements that reveal the impact metamorphism, in the analyzed samples of the Cerro León, evidences that the area of occurrence that would have been indicated as Very Probable Impact Basin, would be more of an Impact Basin.
DS201802-0259
2017
Larroza, F.A.Presser, J.L.B., Alonso, R.N., Farina Dolsa, S., Larroza, F.A., Rocca, M.C.L., Hornes, K., Baller, L.Impact metamorphism evidence of Negla and Yasuka Renda large impact crater. ***PORT only abstract in eng Boletin Museum History Natural Paraguay ***IN PORT, Vol. 21, no. 2, pp. 69-82. pdfSouth America, Paraguayimpact craters
DS201702-0234
2016
Larroza-Cristaldo, F.A.Presser, J.L.B., Farina-Dolsa, S., Larroza-Cristaldo, F.A., Rocca, M., Alonso, R.N., Acededo, R.D., Cabral-Antunez, N.D., Baller, L., Zarza-Lima, P.R., Sekatcheff, J.M.Modeled mega impact structures in Paraguay: II the eastern region. **PortBoletin del Museo Nacional de Historia Narural del Paraguay, Vol. 20, 2, pp. 205-213. pdf available in * PortSouth America, ParaguayImpact Crater

Abstract: We report here the discovery and study of several new modeled large impact craters in Eastern Paraguay, South America. They were studied by geophysical information (gravimetry, magnetism), field geology and also by microscopic petrography. Clear evidences of shock metamorphic effects were found (e.g., diaplectic glasses, PF, PDF in quartz and feldspar) at 4 of the modeled craters: 1) Negla: diameter:~80-81 km., 2) Yasuka Renda D:~96 km., 3) Tapyta, D: ~80 km. and 4) San Miguel, D: 130-136 km. 5) Curuguaty, D: ~110 km. was detected and studied only by geophysical information. Target-rocks range goes from the crystalline Archaic basement to Permian sediments. The modeled craters were in some cases cut by tholeiitic/alkaline rocks of Mesozoic age and partially covered by lavas of the basaltic Mesozoic flows (Negla, Yasuka Renda, Tapyta and Curuguaty). One of them was covered in part by sediments of Grupo Caacupé (age: Silurian/Devonian). Some of these modeled craters show gold, diamonds, uranium and REE mineral deposits associated. All new modeled large impact craters are partially to markedly eroded.
DS2001-0488
2001
LarsenHopper, 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
DS200912-0143
2009
LarsenDale, 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
DS201112-0280
2011
Larsen, B.T.Dominguez, A.R., Van der Voo, R., Torsvik, T.H., Hendriks, B.W.H, Abrajevitch, A., Domeier, M., Larsen, B.T., Rousse, S.The ~270 Ma paleolatitude of Baltica and its significance for Pangea models.Geophysical Journal International, In press availableEurope, Baltic ShieldGeochronology
DS2001-0216
2001
Larsen, D.Cox, R.T., Vn Arsdale, R.B., Harris, J.B., Larsen, D.Neotectonics of the southeastern Reelfoot rift zone margin, central United States And implications for regional strainGeology, Vol. 29, No. 5, May, pp. 419-22.Missouri, Mississippi, MidcontinentTectonics, paleoseismology
DS1930-0197
1935
Larsen, E.S.Larsen, E.S., Hurlburt, C.S. JR., Burgess, C.H., Griggs, D.T.The Igneous Rocks of the Highwood Mountains of Central Montana.American GEOPYS. UNION, Transactions 16TH. MEETING, PP. 288-292.United States, Montana, Rocky MountainsBlank
DS1930-0278
1938
Larsen, E.S.Larsen, E.S., Buie, B.F.Potash Analcime and Pseudoleucite from the Highwood Mountains of Montana.American Mineralogist., Vol. 23, PP.837-849.Montana, Rocky MountainsLeucite
DS1940-0029
1941
Larsen, E.S.Larsen, E.S.Igneous Rocks of the Highwood Mountains, Montana. Part Ii. The Extrusive Rocks.Geological Society of America (GSA) Bulletin., Vol. 52, PP. 1733-1752.Montana, Rocky MountainsBlank
DS1992-1678
1992
Larsen, G.Wilson, M., Rosenbaum, J.M., Dunsworth, E.A., Larsen, G.Are melillitites partial melts of the thermal boundary layer?Eos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.325Europe, GermanyUpper Rhinegraben Volcanic Province, Melillitite
DS2002-0207
2002
Larsen, H.C.Bromann Klausen, M., Larsen, H.C.East Greenland coast parallel dike swarm and its role in continental breakupGeological Society of America Special Paper, No. 192, pp. 133-158.GreenlandDike swarms, Tectonics
DS2002-1137
2002
Larsen, H.C.Nielsen, T.K., Larsen, H.C., Hopper, J.R.Contrasting rifted margin styles south of Greenland: implications for mantle plume dynamics.Earth and Planetary Science Letters, Vol.200,No. 3-4, pp. 271-86.GreenlandTectonics, Geodynamics
DS200412-0217
2002
Larsen, H.C.Bromann Klausen, M., Larsen, H.C.East Greenland coast parallel dike swarm and its role in continental breakup.Geological Society of America Special Paper, No. 192, pp. 133-158.Europe, GreenlandDike swarms Tectonics
DS200412-1932
2004
Larsen, H.C.Storey, M., Pedersen, A.K., Stecher, O., Bernstein, S., Larsen, H.C., Larsen, L.M., Baker, Duncan, R.A.Long lived post breakup magmatism along the East Greenland margin: evidence for shallow mantle metasomatism by the Iceland plumeGeology, Vol. 32, 2, Feb. pp. 173-176.Europe, Greenland, IcelandMagmatism
DS1982-0359
1982
Larsen, J.G.Larsen, J.G.Mantle Derived Dunite and Lherzolite Nodules from Ubekendt Ejland, West Greenland Tertiary Province.Mineralogical Magazine., Vol. 46, No. 340, PP. 329-336.GreenlandKimberlite
DS1992-0567
1992
Larsen, J.G.Gill, R.C.O., Pedersen, A.K., Larsen, J.G.Tertiary picrites in West Greenland: melting at the periphery of a plume?Geological Society Special Publication, Magmatism and the Causes of Continental, No. 68, pp. 335-348GreenlandPicrites, Plume
DS1992-0721
1992
Larsen, J.G.Holm, P.M., Gill, R.C.O., Pedersen, A.K., Larsen, J.G., Hald, N.The Icelandic mantle plume: compositional constraints from the West Greenland Tertiary picritesEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.336GreenlandPicrites, Mantle plume
DS1993-0694
1993
Larsen, J.G.Holm, P.M., Gill, R.C.O., Pedersen, A.K., Larsen, J.G., Hald, N.The Tertiary picrites of West Greenland: contributions from Icelandic and other sourcesEarth and Planetary Science Letters, Vol. 115, No. 1-4, March pp. 227-244GreenlandPicrites, Alkaline rocks
DS1975-1109
1979
Larsen, L.M.Larsen, L.M.Lamprophyric and Kimberlitic Dykes Associated with the Safartoq Carbonatite Complex Southern West Greenland.Greenland Geol. Unders. Rapp., No. 100, Report OF ACTIVITIES, PP. 65-69.GreenlandKimberlite
DS1975-1110
1979
Larsen, L.M.Larsen, L.M.Lampropyric and Kimberlitic Dykes Associated with the Safartoq Carbonatite Complex Southern West Greenland.Greenland Geol. Unders. Rapp., No. 100, PP. 65-69.GreenlandBlank
DS1980-0301
1980
Larsen, L.M.Secher, K., Larsen, L.M.Geology and Mineralogy of the Sarfartoq Carbonatite Complex southern West Greenland.Lithos, Vol. 13, PP. 199-212.GreenlandRelated Rocks
DS1982-0360
1982
Larsen, L.M.Larsen, L.M., Pederson, A.K.A Minor Carbonatite Occurrence in Southern West Greenland, ThetupertalikintrusionGeological Survey Greenland Report of activities, Vol. 110, pp. 38-43GreenlandCarbonatite, Qaqarssuk Complex
DS1983-0388
1983
Larsen, L.M.Larsen, L.M., Rex, D.C., Secher, K.The Age of Carbonatites, Kimberlites and Lamprophyres from Southern West Greenland: Recurrent Alkaline Magmatism During2500 Million Years.Lithos, Vol. 16, No. 3, PP. 215-221.GreenlandGeochronology, Related Rocks, Ivigtut, Fiskenaesset
DS1985-0312
1985
Larsen, L.M.Jones, A.P., Larsen, L.M.Geochemistry and rare earth elements (REE) minerals of nepheline syenites from theMotzfeldtCentre, South GreenlandAmerican Mineralogist, Vol. 70, pp. 1087-1100GreenlandRare Earth Elements (ree), Larvikite, Mineral Chemistry, Rare Earth
DS1985-0382
1985
Larsen, L.M.Larsen, L.M.The Ilimaussaq Intrusion Revisited: the Evolution of an Agpaitic Magma.Conference Report of The Meeting of The Volcanic Studies Gro, 1P. ABSTRACT.Scandinavia, DenmarkGeochemistry
DS1991-0954
1991
Larsen, L.M.Larsen, L.M.Registration of kimberlites and other potentially diamond-bearing rocks inGreenlandGronlands Geol. Unders. Rapp, No. 152, pp. 61-65GreenlandKimberlites, Known localities
DS1991-0955
1991
Larsen, L.M.Larsen, L.M.Occurrences of kimberlite, lamproite and ultramafic lamprophyre inGreenlandGronlands Geologiske Undersogelse, Report No. 91/2, 36p. 5 figs. appendix 9p. 5 maps $20.0GreenlandOccurrences, Kimberlite, lamproite, lamprophyres
DS1992-0909
1992
Larsen, L.M.Larsen, L.M., Rex, D.C.A review of the 2500 MA span of alkaline ultramafic potassic and carbonatitic magmatism in West Greenland (Review)Lithos, Vol. 28, No. 3-6. November pp. 367-402GreenlandAlkaline rocks, Potassic rocks
DS1993-0882
1993
Larsen, L.M.Larsen, L.M., Ronsbo, J.Conditions of origin of kimberlites in West Greenland: new evidence From the Sarfartoq and Sukkertoppen regions.Gronleands Geologiske Undersogelse, Current Research, No. 159, pp. 115-120.GreenlandKimberlite, Genesis
DS1994-1582
1994
Larsen, L.M.Shearer, C.K., Larsen, L.M.Sector zoned aegirine from the Ilmaussaq alkaline intrusion, SouthGreenland: implications for trace element behaviour in pyroxene.American Mineralogist, Vol. 79, No. 3, 4, March-April pp. 340-351.GreenlandAlkaline rocks
DS1998-1022
1998
Larsen, L.M.Mitchell, R.H., Scott Smith, B.H., Larsen, L.M.Mineralogy of ultramafic dikes from the Sarfartoq Sismut and Manitsoqareas, kimberlites or alnoites?7th International Kimberlite Conference Abstract, pp. 600-2.GreenlandClassification - ultramafic dikes, Petrology
DS1999-0484
1999
Larsen, L.M.Mitchell, R.H., Scott Smith, B.H., Larsen, L.M.Mineralogy of ultramafic dikes from the Sarfartoq, Sisimiut and Manitsoq areas, West Greenland.7th International Kimberlite Conference Nixon, Vol. 2, pp. 574-83.GreenlandPetrography - dikes, mica, spinel, ilmenite, Classificication
DS1999-0711
1999
Larsen, L.M.Steenfelt, A., Jensen, S.M., Larsen, L.M., Stendal, H.Diamond exploration in southern West GreenlandAssocation of Exploration Geologists (AEG) 19th. Diamond Exploration Methods Case Histories, pp. 76-84.GreenlandKimberlite - petrology, Sisimuit, Sarfartoq, Maniitsoq
DS2000-0551
2000
Larsen, L.M.Larsen, L.M., Pedersen, A.K.Processes in high magnesium, high 7 magmas: evidence from olivine, chromite and glass in Palaeogene picrites.Journal of Petrology, Vol. 41, No. 7, July pp.1071-98.GreenlandPicrites
DS2003-0774
2003
Larsen, L.M.Larsen, L.M., Pedersen, A.K., Sundvoll, B., Frei, R.Alkali picrites formed by melting of old metasomatized lithospheric mantle: ManitdlatJournal of Petrology, Vol. 44, 1, pp. 3-38.GreenlandPicrites
DS200412-1932
2004
Larsen, L.M.Storey, M., Pedersen, A.K., Stecher, O., Bernstein, S., Larsen, H.C., Larsen, L.M., Baker, Duncan, R.A.Long lived post breakup magmatism along the East Greenland margin: evidence for shallow mantle metasomatism by the Iceland plumeGeology, Vol. 32, 2, Feb. pp. 173-176.Europe, Greenland, IcelandMagmatism
DS200712-1034
2007
Larsen, L.M.Starkey, N., Stuart, F.M., Ellam, R.M., Fitton, J.G., Basu, S., Larsen, L.M.No role for discrete, depleted high 3 He/4He mantle.Plates, Plumes, and Paradigms, 1p. abstract p. A967.Canada, Nunavut, Baffin Island, Europe, GreenlandPicrite
DS200912-0144
2009
Larsen, L.M.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
DS201012-0424
2009
Larsen, L.M.Larsen, L.M., Pedersen, A.K.Petrology of the Paleocene picrites and flood basalts on Disko and Nuussuaq, West GreenlandJournal of Petrology, Vol. 50,9, pp. 1667-1711.Europe, GreenlandPicrite
DS201212-0702
2012
Larsen, L.M.Starkey, N.A., Fitton, J.G., Stuart, F.M., Larsen, L.M.As commodity, is it diamond's time to shine?The New York Times Magazine, April 14, 1p.GlobalDiamond backed exchange traded fund
DS1998-0302
1998
Larsen, M.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.
DS1988-0158
1988
Larsen, O.Dawes, P.R., Larsen, O., Kalsbeek, F.Archean and Proterzoic crust in Northwest Greenland: evidence from Rubidium-Strontium whole rock age determinations.Canadian Journal of Earth Sciences, Vol. 25, pp. 1365-73.GreenlandGeochronology
DS1995-1059
1995
Larsen, R.Larsen, R., Burke, E.A.J., Dobrzhinetskaya, L.F., et al.N2 CO2 CH2 H2O metamorphic fluids in microdiamond bearing lithologies From the western gneiss region.Ngu (norges Geol. Undersoklse, Bulletin., No. 427, pp. 41-43.NorwayDiamonds
DS1998-0830
1998
Larsen, R.B.Larsen, R.B., Eide, E.A., Burke, E.A.J.Evolution of metamorphic volatiles during exhumation of microDiamond bearing granulites Western Gneiss Region.Contributions to Mineralogy and Petrology, Vol. 133, No. 1-2, pp. 106-27.NorwayMicrodiamond, metamorphism
DS1997-0651
1997
Larsen, T.B.Larsen, T.B., Yuen, D.A.Ultrafast upwelling bursting through the upper mantleEarth and Planetary Letters, Vol. 146, No. 3/4. Feb 1, pp. 393-400.MantlePlumes
DS1999-0394
1999
Larsen, T.B.Larsen, T.B., Yuen, D.A., Storey, M.Ultrafast mantle plumes and implications for flood basalt volcanism in the northern Atlantic region.Tectonophysics, Vol. 311, No. 1-4, Sept. 30, pp. 31-82.Baltic States, Quebec, Ungava, Finland, Sweden, NorwayMantle plumes, Flood basalts - review
DS200412-0406
2004
Larsen, T.B.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
DS200712-0204
2007
LarsonCourtier, A.M., Jackson, Lawrence, Wang, Lee, Halama, Warren, Workman, Xu, Hirschmann, Larson, Hart, Lithgo-Bertelloni, Stixrude, ChenCorrelation of seismic and petrologic thermometers suggests deep thermal anomalies beneath hotspots.Earth and Planetary Science Letters, Vol. 264, 1-2, pp. 308-316.MantleGeothermometry
DS200612-0766
2006
Larson, A.M.Larson, A.M., Snoke, J.A., James, D.E.S-wave velocity structure, mantle xenoliths and the upper mantle beneath the Kaapvaal Craton.Geophysical Journal International, Vol. 167, 1, Oct., pp. 171-186.Africa, South AfricaGeophysics - seismics
DS201412-0938
2014
Larson, D.J.Valley, J.W., Cavosie, T., Ushikubo, T., Reinhard, D.A., Lawrence, D.F., Larson, D.J., Clifton, P.H., Kelly, T.F., Wilde, S.A., Moser, D.E., Spicuzza, M.J.Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography.Nature Geoscience, Vol. 7, pp.219-223.MantleGeochronology
DS201509-0434
2015
Larson, D.J.Valley, J.W., Reinhard, D.A., Cavosie, A.J., Ushikubo, T., Lawrence, D.F., Larson, D.J., Kelly, T.F., Snoeyenbos, D.R., Strickland, A.Nano- and micro-geochronology in Hadean and Archean zircons by atom-probe tomography and SIMS: new tools for old minerals.American Mineralogist, Vol. 100, pp. 1355-1377.AustraliaGeochronology

Abstract: Atom-probe tomography (APT) and secondary ion mass spectrometry (SIMS) provide complementary in situ element and isotope data in minerals such as zircon. SIMS measures isotope ratios and trace elements from 1–20 µm spots with excellent accuracy and precision. APT identifies mass/charge and three-dimensional position of individual atoms (±0.3 nm) in 100 nm-scale samples, volumes up to one million times smaller than SIMS. APT data provide unique information for understanding element and isotope distribution; crystallization and thermal history; and mechanisms of mineral reaction and exchange. This atomistic view enables evaluation of the fidelity of geochemical data for zircon because it provides new understanding of radiation damage, and can test for intracrystalline element mobility. Nano-geochronology is one application of APT in which Pb isotope ratios from sub-micrometer domains of zircon provide model ages of crystallization and identify later magmatic and metamorphic reheating.
DS1960-1098
1969
Larson, E.Eggler, D.H., Larson, E., Bradley, W.E.Granites, Grusses and the Sherman Erosion Surface Southern Laramie Range, Colorado-wyoming.American Journal of Science, Vol. 267, No. 4, PP. 510-522.United States, Colorado, Wyoming, State Line, Rocky MountainsBlank
DS1970-0550
1972
Larson, E.E.Kridelbaugh, S.J., Hobbitt, R.P., Kellogg, K., Larson, E.E.Petrologic and Paleomagnetic Implication of the Green Mountain Diatreme.Geological Society of America (GSA), Vol. 4, No. 6, P. 386, (abstract.).United States, Colorado, Rocky Mountains, VermontRelated Rocks
DS1981-0259
1981
Larson, E.E.Larson, E.E., Amini, M.H.Fission Track Dating of the Green Mountain Kimberlite Diatreme Near Boulder Colorado.The Mountain Geologist., Vol. 18, No. 1, PP. 19-22.ColoradoKimberlite, Rocky Mountains
DS1985-0383
1985
Larson, E.E.Larson, E.E., Patterson, P.E., Curtis, G., Drake, R., Mutschler.Petrologic, Paleomagnetic, and Structural Evidence of a Paleozoic Rift System in Oklahoma, New Mexico, Colorado, and Utah.Geological Society of America (GSA) Bulletin., Vol. 96, No. 11, NOVEMBER PP. 1364-1372.United States, Gulf Coast, Colorado Plateau, Oklahoma, New Mexico, ColoradoGeotectonics
DS1992-0910
1992
Larson, G.P.Larson, G.P.Marketing value-added minerals to specialized marketsMining Engineering, Vol. 44, No. 2, February pp. 161-163GlobalEconomics, Markets-specialized
DS1990-0962
1990
Larson, J.E.Jr.Luza, K.V., Larson, J.E.Jr.Seismicity and neotectonics along the southern midcontinent -Texas cratontransectGeological Society of America (GSA) Abstracts with programs, South-Central, Vol. 22, No. 1, p. 14GlobalMidcontinent, Tectonics
DS202002-0201
2019
Larson, K.M.Larson, K.M.Unanticipated uses of the Global Positioning System.Annual Review of Earth and Planetary Sciences, Vol. 47, pp. 19-40.GlobalGPS system

Abstract: Global Positioning System (GPS) instruments are routinely used today to measure crustal deformation signals from tectonic plate motions, faulting, and glacial isostatic adjustment. In parallel with the expansion of GPS networks around the world, several new and unexpected applications of GPS have been developed. For example, GPS instruments are now being used routinely to measure ground motions during large earthquakes. Access to real-time GPS data streams has led to the development of better hazard warnings for tsunamis, flash floods, earthquakes, and volcanic eruptions. Terrestrial water storage changes can be derived from GPS vertical coordinate time series. Finally, GPS signals that reflect on the surfaces below a GPS antenna can be used to measure soil moisture, snow accumulation, vegetation water content, and water levels. In the future, combining GPS with the signals from the Russian, European, and Chinese navigation constellations will significantly enhance these applications.
DS202005-0745
2019
Larson, K.M.Larson, K.M.Unanticipated uses of the Global Positioning System. Just interesting not specific to diamonds.Annual Review of Earth and Planetary Sciences, Vol. 47, pp. 19-40. pdfGlobalGPS

Abstract: Global Positioning System (GPS) instruments are routinely used today to measure crustal deformation signals from tectonic plate motions, faulting, and glacial isostatic adjustment. In parallel with the expansion of GPS networks around the world, several new and unexpected applications of GPS have been developed. For example, GPS instruments are now being used routinely to measure ground motions during large earthquakes. Access to real-time GPS data streams has led to the development of better hazard warnings for tsunamis, flash floods, earthquakes, and volcanic eruptions. Terrestrial water storage changes can be derived from GPS vertical coordinate time series. Finally, GPS signals that reflect on the surfaces below a GPS antenna can be used to measure soil moisture, snow accumulation, vegetation water content, and water levels. In the future, combining GPS with the signals from the Russian, European, and Chinese navigation constellations will significantly enhance these applications. 1) GPS data are now routinely used to study the dynamics of earthquake rupture. 2) GPS instruments are an integral part of warning systems for earth- quakes, tsunamis, flash floods, and volcanic eruptions. 3) Reflected GPS signals provide a new source of soil moisture, snow depth, vegetation water content, and tide gauge data. 4)GPS networks can sense changes in soil moisture, groundwater, and snow depth and thus can contribute to water resource assessments.
DS1997-1112
1997
Larson, M.S.Stone, W.E., Deloule, E., Larson, M.S., Lesher, C.M.Evidence for hydrous high MgO melts in the PrecambrianGeology, Vol. 25, No. 2, Feb. pp. 143-146Ontario, QuebecKomatiites, Abitibi belt
DS200512-0598
2004
Larson, P.Larson, P., Doyle, B., Kivi, K.Utilization of drift exploration techniques to constrain kimberlite indicator dispersal, train sources, Credit Lake property, Nunavut.32nd Yellowknife Geoscience Forum, Nov. 16-18, p.44. (talk)Canada, NunavutGeomorphology - till
DS201608-1388
2016
Larson, P.B.Andersen, A.K., Clar, J.G., Larson, P.B., Neill, O.K.Mineral chemistry and petrogenesis of a HFSE(+HREE) occurrence, peripheral to carbonatites of the Bear Lodge alkaline complex, Wyoming.American Mineralogist, Vol. 101, pp. 1604-1623.United States, Wyoming, Colorado PlateauBear Lodge

Abstract: Rare earth mineralization in the Bear Lodge alkaline complex (BLAC) is mainly associated with an anastomosing network of carbonatite dikes and veins, and their oxidized equivalents. Bear Lodge carbonatites are LREE-dominant, with some peripheral zones enriched in HREEs. We describe the unique chemistry and mineralogy one such peripheral zone, the Cole HFSE(+HREE) Occurrence (CHO), located ~2 km from the main carbonatite intrusions. The CHO consists of anatase, xenotime-(Y), brockite, fluorite, zircon, and K-feldspar, and contains up to 44.88% TiO2, 3.12% Nb2O5, 6.52% Y2O3, 0.80% Dy2O3, 2.63% ThO2, 6.0% P2O5, and 3.73% F. Electron microprobe analyses of xenotime-(Y) overgrowths on zircon show that oscillatory zoning is a result of variable Th and Ca content. Cheralite-type substitution, whereby Th and Ca are incorporated at the expense of REEs, is predominant over the more commonly observed thorite-type substitution in xenotime-(Y). Th/Ca-rich domains are highly beam sensitive and accompanied by high-F concentrations and low-microprobe oxide totals, suggesting cheralite-type substitution is more easily accommodated in fluorinated and hydrated/hydroxylated xenotime-(Y). Analyses of xenotime-(Y) and brockite show evidence of Embedded Image substitution for Embedded Image with patches of an undefined Ca-Th-Y-Ln phosphovanadate solid-solution composition within brockite clusters. Fluorite from the CHO is HREE-enriched with an average Y/Ho ratio of 33.2, while other generations of fluorite throughout the BLAC are LREE-enriched with Y/Ho ratios of 58.6-102.5. HFSE(+HREE) mineralization occurs at the interface between alkaline silicate intrusions and the first outward occurrence of calcareous Paleozoic sedimentary rocks, which may be local sources of P, Ti, V, Zr, and Y. U-Pb zircon ages determined by LA-ICP-MS reveal two definitive 207Pb/206Pb populations at 2.60-2.75 and 1.83-1.88 Ga, consistent with derivation from adjacent sandstones and Archean granite. Therefore, Zr and Hf are concentrated by a physical process independent of the Ti/Nb-enriched fluid composition responsible for anatase crystallization. The CHO exemplifies the extreme fluid compositions possible after protracted LREE-rich crystal fractionation and subsequent fluid exsolution in carbonatite-fluid systems. We suggest that the anatase+xenotime-(Y)+brockite+fluorite assemblage precipitated from highly fractionated, low-temperature (<200 °C), F-rich fluids temporally related to carbonatite emplacement, but after significant fractionation of ancylite and Ca-REE fluorocarbonates. Low-temperature aqueous conditions are supported by the presence of fine-grained anatase as the sole Ti-oxide mineral, concentrically banded botryoidal fluorite textures, and presumed hydration of phosphate minerals. Fluid interaction with Ca-rich lithologies is known to initiate fluorite crystallization which may cause destabilization of (HREE,Ti,Nb)-fluoride complexes and precipitation of REE+Th phosphates and Nb-anatase, a model valuable to the exploration for economic concentrations of HREEs, Ti, and Nb.
DS201709-1951
2017
Larson, P.B.Andersen, A.K., Clark, J.G., Larson, P.B., Donovan, J.J.REE fractionation, mineral speciation, and supergene enrichment of the Bear Lodge carbonatites, Wyoming, USA.Ore Geology Reviews, Vol. 89, pp. 780-807.United States, Wyomingcarbonatite - Bear Lodge

Abstract: The Eocene (ca. 55–38 Ma) Bear Lodge alkaline complex in the northern Black Hills region of northeastern Wyoming (USA) is host to stockwork-style carbonatite dikes and veins with high concentrations of rare earth elements (e.g., La: 4140–21000 ppm, Ce: 9220–35800 ppm, Nd: 4800–13900 ppm). The central carbonatite dike swarm is characterized by zones of variable REE content, with peripheral zones enriched in HREE including yttrium. The principle REE-bearing phases in unoxidized carbonatite are ancylite and carbocernaite, with subordinate monazite, fluorapatite, burbankite, and Ca-REE fluorocarbonates. In oxidized carbonatite, REE are hosted primarily by Ca-REE fluorocarbonates (bastnäsite, parisite, synchysite, and mixed varieties), with lesser REE phosphates (rhabdophane and monazite), fluorapatite, and cerianite. REE abundances were substantially upgraded (e.g., La: 54500–66800 ppm, Ce: 11500–92100 ppm, Nd: 4740–31200 ppm) in carbonatite that was altered by oxidizing hydrothermal and supergene processes. Vertical, near surface increases in REE concentrations correlate with replacement of REE(±Sr,Ca,Na,Ba) carbonate minerals by Ca-REE fluorocarbonate minerals, dissolution of matrix calcite, development of Fe- and Mn-rich gossan, crystallization of cerianite and accompanying negative Ce anomalies in secondary fluorocarbonates and phosphates, and increasing d18O values. These vertical changes demonstrate the importance of oxidizing meteoric water during the most recent modifications to the carbonatite stockwork. Scanning electron microscopy, energy dispersive spectroscopy, and electron probe microanalysis were used to investigate variations in mineral chemistry controlling the lateral complex-wide geochemical heterogeneity. HREE-enrichment in some peripheral zones can be attributed to an increase in the abundance of secondary REE phosphates (rhabdophane group, monazite, and fluorapatite), while HREE-enrichment in other zones is a result of HREE substitution in the otherwise LREE-selective fluorocarbonate minerals. Microprobe analyses show that HREE substitution is most pronounced in Ca-rich fluorocarbonates (parisite, synchysite, and mixed syntaxial varieties). Peripheral, late-stage HREE-enrichment is attributed to: 1) fractionation during early crystallization of LREE selective minerals, such as ancylite, carbocernaite, and Ca-REE fluorocarbonates in the central Bull Hill dike swarm, 2) REE liberated during breakdown of primary calcite and apatite with higher HREE/LREE ratios, and 3) differential transport of REE in fluids with higher PO43-/CO32- and F-/CO32- ratios, leading to phosphate and pseudomorphic fluorocarbonate mineralization. Supergene weathering processes were important at the stratigraphically highest peripheral REE occurrence, which consists of fine, acicular monazite, jarosite, rutile/pseudorutile, barite, and plumbopyrochlore, an assemblage mineralogically similar to carbonatite laterites in tropical regions.
DS1995-0955
1995
Larson, R.Kincaid, C., Larson, R.Slab penetration events through 670 and the evolution of plumes:implications for ocean crustal production.Eos, Vol. 76, No. 46, Nov. 7. p.F172. Abstract.MantlePlumes, Subduction
DS1991-0956
1991
Larson, R.L.Larson, R.L.Latest pulse of earth: evidence for a mid-Cretaceous superplumeGeology, Vol. 19, No. 6, June pp. 547-550GlobalEarth, Superplume
DS1991-0957
1991
Larson, R.L.Larson, R.L.Geological consequences of superplumesGeology, Vol. 19, No. 10, October pp. 963-966GlobalSuperplumes, Pulsation tectonics
DS1991-0958
1991
Larson, R.L.Larson, R.L., Olson, P.Mantle plumes control magnetic reversal frequencyEarth and Planetary Science Letters, Vol. 107, No. 3/4, December pp. 437-447MantlePlumes, Geophysics -magnetics
DS1993-0883
1993
Larson, R.L.Larson, R.L.Mantle plumes and magnetic reversals: a surprising linkEos, Transactions, American Geophysical Union, Vol. 74, No. 4, January 26, p. 46MantleGeophysics -magnetics, Plumes
DS1995-1060
1995
Larson, R.L.Larson, R.L.The Mid Cretaceous superplume episodeScientific American, Vol. 272, No. 2, Feb. pp. 82-86.MantlePlumes, Cretaceous
DS1996-0809
1996
Larson, R.L.Larson, R.L., Kincaid, C.Onset of mid-Cretaceous volcanism by elevation of the 670 km thermal boundary layerGeology, Vol. 24, No. 6, June pp. 551-554Mantle, crustSubduction, slab, Core-mantle boundary
DS2001-0090
2001
Larson, R.L.Bartolini, A., Larson, R.L.Pacific microplate and the Pangea supercontinent in the Early to Middle Jurassic.Geology, Vol. 29, No. 8, Aug. pp. 735-8.PangeaContinents
DS1998-0831
1998
Larson, S.A.Larson, S.A., Tullborg, E.L.Why Baltic shield zircons yield late Paleozoic lower intercept ages on uranium-lead (U-Pb)concordia.Geology, Vol. 26, No. 10, Oct. pp. 919-23.Sweden, Baltic ShieldGeochronology
DS2000-0010
2000
Larson, S.A.Ahall, K.I., Larson, S.A.Growth related 1.85-1.55 Ga magmatism in the Baltic Shield: a review addressing tectonics characteristics.Gff., Vol. 122, pp. 193-206.Finland, Norway, Sweden, Baltic States, FennoscandiaTransscandinavian Igneous Belt, Magmatism, Tectonics
DS201706-1095
2017
Larson, T.Marshak, S., Domrois, S., Abert, C., Larson, T., Pavlis, G., Hamburger, M., Yang, X., Gilbert, H., Chen, C.The basement revealed: tectonic insight from a digital elevation model of the Great Unconformity, USA cratonic platform.Geology, Vol. 45, 5, pp. 391-394.United Statestectonics - Mid continent

Abstract: Across much of North America, the contact between Precambrian basement and Paleozoic strata is the Great Unconformity, a surface that represents a >0.4 b.y.-long hiatus. A digital elevation model (DEM) of this surface visually highlights regional-scale variability in the character of basement topography across the United States cratonic platform. Specifically, it delineates Phanerozoic tectonic domains, each characterized by a distinct structural wavelength (horizontal distance between adjacent highs) and/or structural amplitude (vertical distance between adjacent lows and highs). The largest domain, the Midcontinent domain, includes long-wavelength epeirogenic basins and domes, as well as fault-controlled steps. The pronounced change in land-surface elevation at the Rocky Mountain Front coincides with the western edge of the Midcontinent domain on the basement DEM. In the Rocky Mountain and Colorado Plateau domains, west of the Rocky Mountain Front, structural wavelength is significantly shorter and structural amplitude significantly higher than in the Midcontinent domain. The Bordering Basins domain outlines the southern and eastern edges of the Midcontinent domain. As emphasized by the basement DEM, several kilometers of structural relief occur across the boundary between these two domains, even though this boundary does not stand out on ground-surface topography. A plot of epicenters on the basement DEM supports models associating intraplate seismicity with the Midcontinent domain edge. Notably, certain changes in crustal thickness also coincide with distinct changes in basement depth.
DS201712-2679
2018
Larson, T.Chen, C., Hersh, G., Fischer, K.M., Andronicos, C.L., Pavlis, G.L., Hamburger, M.W., Marshak, S., Larson, T., Yang, X.Lithospheric discontinuities beneath the U.S. Midcontinent - signatures of Proterozoic terrane accretion and failed rifting.Earth and Planetary Science Letters, Vol. 481, pp. 223-235.United States, Illinois, Indiana, Kentuckygeophysics - seismics Reelfoot Rift

Abstract: Seismic discontinuities between the Moho and the inferred lithosphere-asthenosphere boundary (LAB) are known as mid-lithospheric discontinuities (MLDs) and have been ascribed to a variety of phenomena that are critical to understanding lithospheric growth and evolution. In this study, we used S-to-P converted waves recorded by the USArray Transportable Array and the OIINK (Ozarks-Illinois-Indiana-Kentucky) Flexible Array to investigate lithospheric structure beneath the central U.S. This region, a portion of North America's cratonic platform, provides an opportunity to explore how terrane accretion, cratonization, and subsequent rifting may have influenced lithospheric structure. The 3D common conversion point (CCP) volume produced by stacking back-projected Sp receiver functions reveals a general absence of negative converted phases at the depths of the LAB across much of the central U.S. This observation suggests a gradual velocity decrease between the lithosphere and asthenosphere. Within the lithosphere, the CCP stacks display negative arrivals at depths between 65 km and 125 km. We interpret these as MLDs resulting from the top of a layer of crystallized melts (sill-like igneous intrusions) or otherwise chemically modified lithosphere that is enriched in water and/or hydrous minerals. Chemical modification in this manner would cause a weak layer in the lithosphere that marks the MLDs. The depth and amplitude of negative MLD phases vary significantly both within and between the physiographic provinces of the midcontinent. Double, or overlapping, MLDs can be seen along Precambrian terrane boundaries and appear to result from stacked or imbricated lithospheric blocks. A prominent negative Sp phase can be clearly identified at 80 km depth within the Reelfoot Rift. This arrival aligns with the top of a zone of low shear-wave velocities, which suggests that it marks an unusually shallow seismic LAB for the midcontinent. This boundary would correspond to the top of a region of mechanically and chemically rejuvenated mantle that was likely emplaced during late Precambrian/early Cambrian rifting. These observations suggest that the lithospheric structure beneath the Reelfoot Rift may be an example of a global phenomenon in which MLDs act as weak zones that facilitate the removal of cratonic lithosphere that lies beneath.
DS201811-2605
2018
Larson, T.Salminen, J., Hanson, R., Evans, D.A.D., Gong, Z., Larson, T., Walker, O., Gumsley, A., Soderlund, U., Ernst, T.Direct Mesoproterozoic connection of the Congo and Kalahari cratons in proto-Africa: strange attractors across supercontinental cycles.Geology, doi.org/10.1130/G45294.1 4p.Africacraton

Abstract: Mobilistic plate-tectonic interpretation of Precambrian orogens requires that two conjoined crustal blocks may derive from distant portions of the globe. Nonetheless, many proposed Precambrian cratonic juxtapositions are broadly similar to those of younger times (so-called “strange attractors”), raising the specter of bias in their construction. We evaluated the possibility that the Congo and Kalahari cratons (Africa) were joined together prior to their amalgamation along the Damara-Lufilian-Zambezi orogen in Cambrian time by studying diabase dikes of the Huila-Epembe swarm and sills in the southern part of the Congo craton in Angola and in Namibia. We present geologic, U-Pb geochronologic, and paleomagnetic evidence showing that these two cratons were directly juxtaposed at ca. 1.1 Ga, but in a slightly modified relative orientation compared to today. Recurring persistence in cratonic connections, with slight variations from one supercontinent to the next, may signify a style of supercontinental transition similar to the northward motion of Gondwana fragments across the Tethys-Indian oceanic tract, reuniting in Eurasia.
DS201902-0316
2019
Larson, T.Salminen, J., Hanson, R., Evans, D.A.D., Gong, Z., Larson, T., Walker, O., Gumsley, A., Soderlund, U., Ernst, R.Direct Mesoproterozoic connection of the Congo and Kalahari cratons in proto-Africa: strange attractors across supercontinental cycles.Geology, Vol. 46, pp. 1101-1104.Africa, Angola, Namibiacraton

Abstract: Mobilistic plate-tectonic interpretation of Precambrian orogens requires that two conjoined crustal blocks may derive from distant portions of the globe. Nonetheless, many proposed Precambrian cratonic juxtapositions are broadly similar to those of younger times (so-called “strange attractors”), raising the specter of bias in their construction. We evaluated the possibility that the Congo and Kalahari cratons (Africa) were joined together prior to their amalgamation along the Damara-Lufilian-Zambezi orogen in Cambrian time by studying diabase dikes of the Huila-Epembe swarm and sills in the southern part of the Congo craton in Angola and in Namibia. We present geologic, U-Pb geochronologic, and paleomagnetic evidence showing that these two cratons were directly juxtaposed at ca. 1.1 Ga, but in a slightly modified relative orientation compared to today. Recurring persistence in cratonic connections, with slight variations from one supercontinent to the next, may signify a style of supercontinental transition similar to the northward motion of Gondwana fragments across the Tethys-Indian oceanic tract, reuniting in Eurasia.
DS201412-0220
2014
larson, T.E.Eiler, J.M., Berquist, B., Bourg, I., Cartigny, P., Farquhar, J., Gagnon, A., Guo, W., Halevy, I., Hofman, A., larson, T.E., Levin, N., Schauble, E.A., Stolper, D.Frontiers of stable isotope geoscience.Chemical Geology, Vol. 372, pp. 119-143.TechnologyReview of isotopes
DS1999-0395
1999
Larsson, J.O.Larsson, J.O.Europe: a new diamond province?North Atlantic Mineral Symposium, Sept., abstracts pp. 172-74.Finland, Russia, Kola, Sweden, Ireland, Baltic States, EuropeExploration - brief review
DS1998-0832
1998
Larsson, J-O.Larsson, J-O.Recent developments in diamond exploration in Sweden... legal framework, licences, history, companies active.Raw Materials Report, Vol. 13, No. 1, pp. 17-26.SwedenHistory, legal, Current activities, companies
DS1986-0484
1986
Larsson, S.Y.Larsson, S.Y., Stearn, C.W.Silurian stratigraphy of the Hudson bay Lowland in QuebecCanadian Journal of Earth Sciences, Vol. 23, pp. 288-99.QuebecStratigraphy
DS200912-0203
2009
Larsson, V.Ericsson, M., Larsson, V.E & MJ's annual survey of global mining investment.Engineering and Mining Journal, Jan-Feb. pp. 24-28.GlobalEconomics
DS201212-0186
2012
Larsson, V.Ericsson, M., Larsson, V.E & MJ's annual survey of global mining investment.E & MJ, Jan. pp. 24-29.GlobalMentions diamonds
DS1940-0073
1943
Larsson, W.Larsson, W.Zur Kenntnis der Alkalinen Ultrabasisc hen Ganggesteine der Kalix Gebiets Nord Schweden.Sveriges Geol. Unders. Arsbok, SER. C, No. 456. ARSBOK 37, No. 5, PP. 3-41.Sweden, ScandinaviaAlnoite, Mineralogy, Petrology
DS1998-0833
1998
Larter, R.D.Larter, R.D., King, E.C., Leat, P.T., Reading, SmellieSouth Sandwich slices reveal much about arc structure, geodynamics andcomposition.Eos, Vol. 79, No. 24, June 16, p. 281, 284-5.GlobalGeodynamics - not specific to diamonds, Arc structure
DS1982-0361
1982
Larue, D.K.Larue, D.K., Ueng, W.L.Early Proterozoic Arc-continent Collision Orogen, Lake Superior Region: Tectono-stratigraphic Terranes.Geological Society of America (GSA), Vol. 14, No. 7, P. 542, (abstract.).GlobalMid-continent
DS1983-0389
1983
Larue, D.K.Larue, D.K.Early Proterozoic Tectonics of the Lake Superior Region: Tectonostratigraphic Terranes Near the Purported Collision Zone.Geological Society of America (GSA) MEMOIR., No. 160, PP. 33-48.GlobalMid-continent
DS1985-0134
1985
Lasag, A.C.Cygan, R.T., Lasag, A.C.Self Diffusion of Magnesium in Garnet at 750 to 900 CAmerican Journal of Science, Vol. 285, April pp. 328-350GlobalBlank
DS1982-0161
1982
Lasaga, A.C.Cygan, R.T., Lasaga, A.C.Crystal Growth and the Formation of Chemical Zoning in GarnetsContributions to Mineralogy and Petrology, Vol. 79, pp. 187-200.GlobalMineralogy - Garnets
DS1989-0116
1989
Lasaga, A.C.Berner, R.A., Lasaga, A.C.Modeling the geochemical carbon cycleScientific American, Vol. 260, No. 3, pp. 74-81. Database # 17584GlobalGreenhouse effect, Geochemistry
DS1992-1468
1992
Lasaga, A.C.Steefel, C.I, Lasaga, A.C.Transport into water-rock interaction modelsGeology, Vol. 20, No. 8, August pp. 680-684GlobalFluid flow paths, Water-rock interaction
DS2001-0654
2001
Lasaga, A.C.Lasaga, A.C., Rye, D.M., Bolton, E.W.Calculation of fluid fluxes in Earth's CrustGeochimica et Cosmochimica Acta, Vol. 65, No. 7, pp. 1161-85.MantleGeochemistry - fluid flux models
DS1993-0096
1993
LaSalle, P.Beaumier, M., Dion, D-J., LaSalle, P., Moorhead, J.Exploration du diamant au Temiscamingue. (in French)Quebec Department of Mines Promotional, PRO 93-08, 7p.Quebec, TimiskamingGeochemistry, Heavy minerals-brief overview
DS1994-0123
1994
Lasalle, P.Beaumier, M., Lasalle, P., Warren, B., Lasalle, Y.R.Mineraux indicateurs de kimberlite dans les eskers du nord ouest Quebecois.(in French)Quebec Department of Mines, MB 93-60 1 map 1: 250, 000 paper copy $ 3.50QuebecGeochemistry, Mineralogy
DS1994-0123
1994
Lasalle, Y.R.Beaumier, M., Lasalle, P., Warren, B., Lasalle, Y.R.Mineraux indicateurs de kimberlite dans les eskers du nord ouest Quebecois.(in French)Quebec Department of Mines, MB 93-60 1 map 1: 250, 000 paper copy $ 3.50QuebecGeochemistry, Mineralogy
DS1993-1417
1993
Laschen..VA.Sekerin, A.P., Mensgagin, Y.V., Laschen..VA.Dokembrian lamproites of the Prisayan. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 329, No. 3, March pp. 328-331. # LG762RussiaLamproites
DS1910-0199
1911
Laschinger, E.J.Laschinger, E.J.The Kimberley and Rand Systems of Mining Compared. Discussion of Williams's Paper Entitled the Kimberley System of Handling Large Quantities of Ground.South African Mining Journal, Vol. 9, PT. 1, MAY 27TH. PP. 553-554.South AfricaMining Methods
DS1988-0404
1988
Lash, G.G.Lash, G.G.Along strike variations in foreland basin evolution: possible evidence for continental collision along an irregular marginBasin Research, Vol. 1, No. 2, June pp. 71-84GlobalBasin, Tectonics
DS1988-0622
1988
Lashchenov, V.A.Sekerin, A.P., Menshagin, I.V., Lashchenov, V.A.Alkaline-ultrabasic rocks and carbonatites of the eastern Sayan. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 299, No. 3, pp. 711-714RussiaBlank
DS1989-1367
1989
Lashchenov, V.A.Sekerin, A.P., Menshagin, Yu.V., Lashchenov, V.A., Tverdokh, ebova, A.A.New occurrence of carbonatites and the structural control of alkaline Rocks in the eastern Sayan Province, USSR. (Russian)Izk. Iruktsk. USSR. Izv. Akad. Nauk SSSR, No. 8, pp. 34-41RussiaAlkaline rocks, Carbonatite
DS1991-1538
1991
Lashchenov, V.A.Sekerin, A.P., Menshagin, V., Vladimirov, B.M., Lashchenov, V.A.Precambrian diamond bearing veined bodies from southwest of the SiberianPlatformProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 543-544RussiaVeins, lamproite, Chrome spinellids, geochronology
DS1992-1363
1992
Lashchenov, V.A.Sekerin, A.P., Menshagin, Yu.V., Lashchenov, V.A.New dat a on Precambrian kimberlites from the near Sayan regionSoviet Geology and Geophysics, Vol. 32, No. 12, pp. 57-63.Russia, SayanKimberlites, Textures
DS1995-1697
1995
Lashchenov, V.A.Sekerin, A.P., Menshagin, Yu.V., Lashchenov, V.A.Sayan Precambrian lamproitesDoklady Academy of Sciences, Vol. 329A, No. 3, April, pp. 99-104.Russia, SayanLamproites
DS1996-1276
1996
Lashchenov, V.A.Sekerin, A.P., Menshagin, Yu.V., Lashchenov, V.A.Origin of ultrabasic rocks of the dunite harzburigite association occurring in the Main Sayan Fault zone.Doklady Academy of Sciences, Vol. 340, No. 2, March., pp. 89-95.RussiaSiberian Craton, Malyy Tagui
DS1995-1698
1995
Lashenov, V.A.Sekerin, A.P., Menshagin, Yu.V., Lashenov, V.A.high Pressureotassic mantle magmatism and the problems of diamond bearing in the Irkutsk Prisyanye area.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 492-493.Russia, Irkutsk, PrisyanyeLamproite, Deposit -Ingashinskoe
DS2001-0767
2001
LashkevichMedvedev, V.Ya., Ivanova, Egorov, Lashkevich, UshchapovKelyphitic rims around garnet in kimberlites: an experimental studyDoklady, Vol.381A, No.9, Nov-Dec. pp. 1096-98.RussiaKimberlite - garnet mineralogy
DS200412-1086
2004
Lashkevich, V.V.Lashkevich, V.V., Medvedev, V.Y., Egorov, K.N., Ivanova, L.A.Experimental and numerical modeling of the metasomatic replacement of picroilmenites from kimberlites.Geochemistry International, Vol. 42, 1, pp. 49-56.RussiaMetasomatism, Deposit - Jubileinaya
DS201810-2352
2018
Lasiter, J.C.Marshall, E.W., Lasiter, J.C., Barnes, J.D.On the (mis) behavior of water in the mantle: controls on nominally anhydrous mineral water content in mantle peridotites.Earth and Planetary Science Letters, Vol. 499, pp. 219-229.United States, Colorado Plateaumetasomatism

Abstract: In magmatic settings, water behaves as an incompatible species and should be depleted during melting and enriched during metasomatism. Previous studies have identified correlations between nominally anhydrous mineral (NAM) water content ([H2O]) and indices of metasomatism or melt extraction, seemingly confirming this behavior in the mantle. However in detail, these correlations are ambiguous and do not reflect robust controls on NAM [H2O]. We measured orthopyroxene (opx) and clinopyroxene (cpx) [H2O] in variably hydrated and metasomatized peridotite xenoliths from the Navajo volcanic field (NVF) that sample the Colorado Plateau subcontinental lithospheric mantle (SCLM), an endmember of SCLM hydration and metasomatism. These xenoliths span a wide range of pyroxene [H2O] (opx from 50 to 588 ppm wt. H2O; cpx from 38 to 581 ppm wt. H2O), but NAM [H2O] does not correlate with either indices of melt depletion or metasomatism. Growth of hydrous minerals suggests higher water activity than in anhydrous peridotites, and therefore hydrous-mineral-bearing xenoliths and anhydrous xenoliths should have different NAM [H2O] and water activities. However, when the two groups are compared no significant differences can be found in either NAM [H2O] or water activity. We propose that the high diffusivity of hydrogen in the mantle allows for equilibration of water activity in the mantle over sub-kilometer length scales over geologic time. Such diffusive equilibration reduces water activity variability and results in the blurring and destruction of correlations between NAM [H2O] and indices of metasomatism or melt extraction. As a result of diffusive equilibration of water, there is a large difference in the variability of concentration between NAM [H2O] (spanning ~2 orders of magnitude) and similarly incompatible elements such as Ce in the same peridotites (spanning ~4 orders of magnitude). This difference in behavior explains why H2O/Ce ratios in mantle peridotites are highly variable relative to those of basalts.
DS201112-0100
2011
Laskar, J.Boulila, S., Galbrun, B., Miller, K.G., Pekar, S.F., Browning, J.V., Laskar, J., Wright, J.D.On the origin of Cenozoic and Mesozoic 'third order' eustatic sequences.Earth Science Reviews, Vol. 109, 3-4, pp. 94-112.GlobalGeomorphology - sea levels
DS200612-1616
2006
Laske, G.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
Laske, G.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
DS200512-0714
2005
Laskevich, V.V.Medvedev, V.Y., Ivanova, L.A., Egorov, K.N., Laskevich, V.V.Formation of kelphytic rims around garnet in kimberlites: experimental and physicochemical modeling.Geochemistry International, Vol. 43, 8, pp. 769-775.RussiaMineral chemistry
DS1991-0514
1991
Laskey, R.Friday, L., Laskey, R.The fragile environment: new approaches to global problemsCambridge University of Press, $ 15.95 approx, GlobalBook -ad, Fragile environment
DS1983-0390
1983
Lasko, YE.YE.Lasko, YE.YE., Koptil, V.I., et al.Fassaite Clinpoyroxenes from Diamond Bearing Kyanite Eclogite Xenoliths.Doklady Academy of Sciences ACAD. NAUK USSR EARTH SCI. SECTION., Vol. 258, No. 1-6, PP. 138-142.Russia, YakutiaMineral Chemistry, Sytykan, Pipe, Analyses
DS1985-0083
1985
Lasnier, B.Boyer, H., Smith, D.C., Chopin, C., Lasnier, B.Raman Microprobe (rmp) Determinations of Natural and Synthetic Coesite.Physics Chem. Minerals, Vol. 12, No. 1, PP. 45-48.South Africa, NorwayEclogite, Roberts Victor, Westen Gneiss, Dora Maira, Brytting
DS1991-0234
1991
Lasnier, B.M.Castelo Branco, R.M.G., Lasnier, B.M.Geology and geophysics of the Redondao kimberlite diatreme northeasternBrasilProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 35-37BrazilGeophysics -magnetics, Structure -Redondao
DS2003-1343
2003
Lass Evans, S.Stuart, F.M., Lass Evans, S., Fitton, J.G., Ellam, R.M.High 3 He 4 He ratios in picritic basalts from Baffin Island and the role of a mixedNature, No. 6944, July 3, pp. 57-59.Northwest Territories, Baffin Island, NunavutPicrites
DS200412-1942
2003
Lass Evans, S.Stuart, F.M., Lass Evans, S., Fitton, J.G., Ellam, R.M.High 3 He 4 He ratios in picritic basalts from Baffin Island and the role of a mixed reservoir in mantle plumes.Nature, No. 6944, July 3, pp. 57-59.Canada, Nunavut, Baffin IslandPicrite
DS200612-0767
2006
Lassak, T.M.Lassak, T.M., Fouch, M.J., Hall, C.E., Kaminski, E.Seismic characterization of mantle flow in subduction systems: can we resolve a hydrated mantle wedge?Earth and Planetary Science Letters, Vol. 243, 3-4, March 30, pp. 632-649.MantleSubduction, water
DS200712-0597
2007
Lassak, T.M.Lassak, T.M., McNamara, A.K., Zhong, S.Influence of thermochemical piles on topography at Earth's core-mantle boundary.Earth and Planetary Science Letters, Vol. 261, 3-4, pp. 443-455.MantleGeothermometry
DS201012-0425
2010
Lassak, T.M.Lassak, T.M., McNamara, A.K., Garnero, E.J., Zhong, S.Core mantle boundary topography as a possible constraint on lower mantle chemistry and dynamics.Earth and Planetary Science Letters, Vol. 289, pp. 232-241.MantleConvection, plumes
DS2002-0899
2002
Lassen, A.Krawczyk, C.M., Eilts, F., Lassen, A., Thybo, H.Seismic evidence of Caledonian deformed crust and uppermost mantle structures in the northern part of the Trans European Suture Zone, SW Baltic Sea.Tectonophysics, Vol. 360, 1-4, pp. 215-44.Europe, Baltic SeaTectonics
DS200712-0840
2006
Lassen, A.Pharaoh, T.C., Winchester, J.A., Verniers, J., Lassen, A., Seghedi, A.The Western accretionary margin of the East European Craton: an overview.Geological Society of London Memoir, No. 32, pp. 291-312.Russia, Europe, UralsCraton
DS1991-0971
1991
Lasserre, J-L.Ledru, P., Lasserre, J-L., Manier, E., Mercier, D.The lower Proterozoic of northern Guiana: a revision of the lithology, transcurrent tectonics and sedimentary basin dynamicsBulletin Societe Geologique France, Vol. 162, No. 4, pp. 627-636GlobalBasin, Tectonics
DS1991-1477
1991
Lassiter, J.Rutz, J., Rattray, G., Wendlandt, E., Lassiter, J.Evolution of Lower crust: granulite facies xenoliths from cratons andriftsEos Transactions, Vol. 72, No. 44, October 29, abstract p. 543MantleDiatremes, Xenoliths
DS1995-1061
1995
Lassiter, J.C.Lassiter, J.C., De Paolo, D.J., Mahoney, J.J.Geochemistry of Wrangellia flood basalt province: implications for the roleof continental lithosphere.Journal of Petrology, Vol. 96, No. 4, pp. 983-1009United States, Wrangellia TerraneBasalt, Flood basalt genesis
DS200512-0599
2004
Lassiter, J.C.Lassiter, J.C.Role of recycled oceanic crust in the potassium and argon budget of the Earth: toward a resolution of the 'missing argon' problem.Geochemistry, Geophysics, Geosystems: G3, Vol. 5, pp. Q11012 10.1029/2004 GC000711MantleGeochemistry, cycles
DS200612-0768
2006
Lassiter, J.C.Lassiter, J.C.Constraints on the coupled thermal evolution of the Earth's core and mantle, the age of the inner core, and origin of the 186Os /1880s core signal in plume lavasEarth and Planetary Science Letters, Vol. 250, 1-2, pp. 306-317.MantleGeochronology
DS200612-0769
2006
Lassiter, J.C.Lassiter, J.C.Constraints on the age of the Earth's inner core and the origin of the 186 Os 188 Os core signal in plume related lavas.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 343, abstract only.MantleGeochronology
DS200612-0770
2006
Lassiter, J.C.Lassiter, J.C.Constraints on the coupled thermal evolution of the Earth's core and mantle, the age of the inner core and the origin of the 186 Os 188 Os core signal in plume..Earth and Planetary Science Letters, In press - availableUnited States, HawaiiGeothermometry - potassium, not specific to diamonds
DS201610-1849
2016
Lassiter, J.C.Chatterjee, R., Lassiter, J.C.186Os/188Os variations in upper mantle peridotites: constraints on the Pt/Os ratio of primitive upper mantle, implications for late veneer accretion and mantle mixing timescales.Chemical Geology, Vol. 442, pp. 11-22.United States, Colorado PlateauPeridotite

Abstract: 186Os/188Os variations in mantle peridotites provide constraints on the long-term Pt/Os evolution of the depleted mantle and the Pt/Os ratio of the primitive upper mantle (PUM). We report new 186Os/188Os data for mantle peridotites from continental (Rio Grande Rift and Colorado Plateau) and oceanic (Lena Trough and Hawaiian Islands) settings that span a wide range in fertility (Al2O3 ˜ 0.67-4.42 wt.%) and 187Os/188Os ratios (0.1138-0.1305). Although peridotite 186Os/188Os values span only a narrow range (from 0.1198345 to 0.1198384), 186Os/188Os broadly correlates with indices of melt depletion including bulk rock Al2O3, spinel Cr#, and clinopyroxene Cr#, consistent with Pt depletion in residual peridotites. PUM 186Os/188Os is estimated to be 0.1198378 ± 23 (2 SD) based on extrapolation of 186Os/188Os-fertility trends, which is very slightly lower than H-chondrites [˜ 0.1198398 ± 16 (2 SD); Brandon et al., 2006]. This value is consistent with a PUM Pt/Os of 1.7 ± 0.2, similar to average Pt/Os ratios of fertile continental peridotites. The inferred PUM Pt/Os is slightly lower than but within error of Pt/Os values measured in several classes of chondrites [Carbonaceous ˜ 1.8 ± 0.2, Ordinary ˜ 1.9 ± 0.1, and Enstatite ˜ 1.9 ± 0.1 (Brandon et al., 2006)] indicating that PUM Pt/Os is broadly chondritic. In contrast, estimates for PUM Ru/Ir and Pd/Ir (cf. Becker et al., 2006) are suprachondritic. The addition of a chondritic late veneer alone cannot create a combination of chondritic and suprachondritic HSE ratios for the PUM. Instead, minor core segregation occurring concurrently with the addition of a late veneer may explain the observed mantle HSE abundances and ratios. Combined 186Os/188Os-187Os/188Os isotopic and Pt/Os and Re/Os variability in peridotites suggest an average mantle homogenization timescale of ~ 1.2 Ga. In contrast, combined Hf-Nd isotopic and Lu/Hf and Sm/Nd variability in peridotites indicate much shorter homogenization timescales (< 0.4 Ga), potentially reflecting enhanced homogenization by melt-rock interaction to which the Pt-Os and Re-Os systems are relatively immune. The mechanical mixing timescale inferred from Os isotopes is consistent with timescales predicted for whole mantle convection.
DS201707-1348
2017
Lassiter, J.C.Marshall, E.W., Lassiter, J.C., Barnes, J.D., Luguet, A., Lissner, M.Mantle melt production during the 1.4 Ga Laurentian magmatic event: isotopic constraints from Colorado Plateau mantle xenoliths.Geology, Vol. 45, 6, pp. 519-522.United States, Colorado Plateaumelting - Navajo Volcanics

Abstract: Plutons associated with a 1.4 Ga magmatic event intrude across southwestern Laurentia. The tectonic setting of this major magmatic province is poorly understood. Proposed melting models include anorogenic heating from the mantle, continental arc or transpressive orogeny, and anatexis from radiogenic heat buildup in thickened crust. Re-Os analyses of refractory mantle xenoliths from the Navajo volcanic field (NVF; central Colorado Plateau) yield Re depletion ages of 2.1–1.7 Ga, consistent with the age of the overlying Yavapai and Mazatzal crust. However, new Sm-Nd isotope data from clinopyroxene in peridotite xenoliths from NVF diatremes show a subset of xenoliths that plot on a ca. 1.4 Ga isochron, which likely reflects mantle melt production and isotopic resetting at 1.4 Ga. This suggests that Paleoproterozoic subcontinental lithospheric mantle was involved in the 1.4 Ga magmatic event. Our constraints support a subduction model for the generation of the 1.4 Ga granites but are inconsistent with rifting and anorogenic anatexis models, both of which would require removal of ancient lithosphere.
DS201803-0464
2017
Lassiter, J.C.Marshall, E.W., Barnes, J.D., Lassiter, J.C.The role of serpentinite derived fluids in metasomatism of the Colorado Plateau ( USA) lithospheric mantle.Geology, Vol. 45, 12, pp. 1103-1106.United States, Colorado Plateausubduction

Abstract: Subducting serpentinized lithosphere has distinct dD and d18O values compared to normal mantle. Slab-derived fluids that infiltrate the mantle wedge can alter its oxygen and hydrogen isotope composition, raising or lowering the d18O and dD values depending on the nature of the subducted components. Hydrous minerals in peridotite xenoliths from the Colorado Plateau (southwestern USA) have dD values (up to -33‰) much higher than average mantle (-80‰), but similar to dD values of olivine-hosted melt inclusions within arc basalts, suggesting a slab-derived fluid source. Oxygen isotope ratios of olivine from these xenoliths are similar to average mantle, yet display a strong negative correlation with clinopyroxene Ce/Sm, a proxy of metasomatism. This correlation is most simply explained by metasomatism from fluids derived from the serpentinized portion of the Farallon slab. Although d18O values of mantle minerals span a narrow range, integration of stable isotope data with other geochemical tracers can provide new constraints on modern and ancient subduction-related processes, potentially providing a method for probing Archean lithospheric mantle for evidence of early subduction.
DS201809-2053
2018
Lassiter, J.C.Lassiter, J.C.On the equilibration timescales of isolated trace phases in mantle peridotites: implications for the interpretation of grain scale isotope heterogeneity in peridotitic sulfides.Earth and Planetary Science Letters, Vol. 498, pp. 427-435.Mantleperidotites

Abstract: Geochemical studies of mid-ocean-ridge basalts (MORB) and mantle peridotites (e.g., abyssal peridotites) provide independent constraints on the composition and evolution of the convecting mantle. Recent studies have revealed systematic differences in the radiogenic isotope compositions of MORB and abyssal peridotites that call into question the complementary nature of these two windows to the upper mantle. The origin of these differences is fundamental to our understanding of MORB petrogenesis and the composition and depletion history of the upper mantle. The use of isotope variations in basalts to probe the composition and evolution of the mantle is predicated on the assumption of local (i.e., grain-scale) isotopic equilibrium during mantle melting. However, several studies have reported Os- and Pb-isotope disequilibrium in distinct populations of peridotite-derived sulfides, with sulfides included within silicate grains typically possessing more “depleted” isotopic compositions than interstitial sulfides. In principle, grain-scale isotopic heterogeneity could reflect variable radiogenic ingrowth in ancient sulfides with variable parent/daughter ratios, or partial re-equilibration of low-Re/Os and U/Pb sulfides with more radiogenic silicate phases along grain boundaries during mantle melting. This would require that sulfides fail to maintain isotopic equilibrium with neighboring phases over geologically long (~ Ga) time scales. The preservation of Os-isotope disequilibrium in peridotites has been ascribed in several studies to the armoring effect of low-[Os] silicates, which limits diffusive exchange between isolated Os-rich sulfides. This raises the prospect that peridotite-derived melts may not inherit the Os- (or Pb-) isotope composition of their source, which could account for the recently documented systematic differences in the Os- and Pb-isotope compositions of MORB and mantle peridotites. Although the preservation of isotopic heterogeneity in mantle sulfides is commonly ascribed to the above “armoring effect”, the diffusive equilibration timescale of spatially separated sulfides in mantle peridotites has not previously been rigorously estimated. This study examines the parameters that control this equilibration timescale (average sulfide size and spacing, Os and Pb diffusivity in armoring silicate minerals, and element partitioning between silicate and sulfide phases). Equilibration timescale estimates using available constraints on these parameters reveal that most mantle sulfides are expected to isotopically re-equilibrate with neighboring sulfides in less than a few 10 s of Myr at convecting mantle temperatures. Maintenance of isotopic disequilibrium over the ~ Ga timescales suggested by observed intra-sample Os- and Pb-isotope heterogeneity requires very large sulfides (>100 µm) separated by several mm or diffusion rates (D <10-18 m2/s), slower than for most elements in olivine. Combined with the observation of intra-sample major element heterogeneity in sulfide Ni and Fe abundances (which should equilibrate quickly in the convecting mantle), these results suggest that the observed isotopic disequilibrium is unlikely to be an ancient feature in mantle peridotites. Instead, recent sulfide metasomatism linked to interaction with melts derived from isotopically enriched eclogite or pyroxenite (or fertile and/or metasomatized peridotite) components is a more likely explanation for observed intra-sample isotopic heterogeneity in peridotites. This interpretation is also consistent with systematic differences between the Nd- and Hf-isotope compositions of MORB and abyssal peridotites. These results further strengthen the proposal that MORB do not accurately reflect the average isotopic composition of the convecting upper mantle, and that upper mantle peridotite is, on average, significantly more depleted and refractory than suggested by MORB-based estimates. The effects of melt generation in a heterogeneous marble-cake mantle need to be explicitly considered when using basalt compositions to constrain mantle composition and evolution.
DS201809-2068
2018
Lassiter, J.C.Marshall, E.W., Lassiter, J.C., Banes. J.B.Understanding the (mis) behaviour of water contents in nominally anhydrous mantle minerals.Goldschmidt Conference, 1p. AbstractMantleperidotites

Abstract: The H/C ratio in earth’s exosphere is higher than it is in the source region of primitive basalts, suggesting an enriched carbon reservoir in the mantle[1]. A plausible explanation is that subduction of carbon may have enriched the mantle in recycled carbon over time. Average basaltic crust contains ~ 2 wt.% CO2 [2], and modeling of slab devolatilisation suggests that subducted carbonate may survive to be transported deeper into the mantle [3]. Carbonated oceanic crust should melt in the transition zone along most subduction geotherms due to a deep trough in the carbonated basalt solidus, and mineral inclusions in superdeep diamonds testify to carbonate melt in their formation [4]. Along cool subduction geotherms carbonate may subduct into the lower mantle, potentially enriching the deep mantle in carbon. Here we report on laser-heated diamond anvil cell experiments in the CaO-MgO-SiO2-CO2 and FeO-MgO-SiO2-CO2 systems at lower mantle pressures where we investigate the stability of carbonate in oceanic crust, and test for decarbonation and diamond forming reactions involving carbonate and coexisiting free silica. We find that carbonate reacts with silica to form bridgmanite ± Ca-perovskite + CO2 at pressures in the range of ~50 to 70 GPa. These decarbonation reactions form an impenetrable barrier to subduction of carbonate into the deeper lower mantle, however, slabs may carry solid CO2 (Phase V) into the deeper lower mantle. We also identify reactions where carbonate or CO2 dissociate to form diamond plus oxygen. We suggest that the deep lower mantle may become enriched in carbon in the form of diamond over time due to subduction of carbonate and solid CO2 and its eventual dissociation to form diamond plus oxygen. Release of oxygen during diamond formation may also provide a mechanism for locally oxidizing the deep mantle.
DS201012-0763
2010
Lassonde, J.Strand, P., Lassonde, J., Burgess, J.Transforming a diamond mine: the Jericho diamond mine update.38th. Geoscience Forum Northwest Territories, Abstract pp.87-88.Canada, NunavutJericho project
DS201112-1011
2011
Lassonde, J.Strand, P., Lassonde, J.Geological and project update: Jericho diamond mine, Nunavut.Yellowknife Geoscience Forum Abstracts for 2011, abstract p. 81-82.Canada, NunavutGeology - model
DS200412-1087
2003
Lassonde, P.Lassonde, P.How to earn your social licence.. without local community support, your project is going nowhere.Mining Review, Summer, pp. 7,9,10,11,13.GlobalLegal - social
DS1996-1045
1996
LastNyblade, A.A., Birt, C., Langston, C.A., Owens, T.J., LastSeismic experiment reveals rifting of Craton in TanzaniaEos, Vol. 77, No. 51, Dec. 17, p. 517, 521.TanzaniaGeophysics - seismics, Craton
DS201112-0867
2011
LastochkinRipp, G.S., Doboshkevich, A.G., Ripp, G.S., Lastochkin, Izbrodin, RampilovA way of carbonatite formation from alkaline gabbros, Oshurkovo massif.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.39-41.RussiaOshurkovo
DS201112-0868
2011
LastochkinRipp, G.S., Doboshkevich, A.G., Ripp, G.S., Lastochkin, Izbrodin, RampilovA way of carbonatite formation from alkaline gabbros, Oshurkovo massif.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.39-41.RussiaOshurkovo
DS200612-0771
2006
Lastochkin, E.I.Lastochkin, E.I., Ripp, G.S., Doroshkevich, A.G., Badmatsirenov, M.V.Metamorphism of the Vesloe carbonatites, north Transbaikalia, Russia.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 207-RussiaCarbonatite
DS1987-0397
1987
Lastovickova, M.Lastovickova, M., Ramana, Y.V., Gogte, B.S.Electrical conductivity of some rocks from the Indian subcontinentStudies Geophysics Geody, Vol.31, No. 1 pp. 60-72IndiaGeophysics, Kimberlite
DS2001-0655
2001
Lastowika, L.A.Lastowika, L.A., Sheehan, A.F., Schneider, J.M.Seismic evidence for partial lithospheric delamination model of Colorado Plateau Uplift.Geophysical Research Letters, Vol. 28, No. 7, April 1, pp.1319-22.Colorado PlateauTectonics, Geophysics - seismics
DS2000-0552
2000
Lastowka, L.A.Lastowka, L.A.Western United States upper mantle velocity structure from PN arrivals and Rayleigh wave dispersion data.Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-103.Colorado PlateauGeophysics - seismics, Tectonics
DS1860-0559
1887
Latchinoff, M.M.Latchinoff, M.M., Joefeif.Meteorite from Novy Urej Penza SiberiaNature., Dec. 1ST.RussiaMeteorite
DS201112-0569
2011
LatelineLatelineRio Tinto accused of threatening endangered tigers.... Bundar area.abc.net.au, Dec. 1, 2p.IndiaNews item - Rio Tinto
DS1988-0405
1988
Latham, L.R.Latham, L.R., Newill, R.J., Wallin, E.T.uranium-lead (U-Pb) (U-Pb) geochronology of southern MissouriGeological Society of America Abstracts with Program, Vol. 20, No. 2, January p. 122. Sth. Central, LawrenceMissouriMid continent
DS1986-0348
1986
Latham, T.Hauser, E.C., Barnes, A., Gephart, J., Latham, T., Lundy, J.Brown.COCORP deep reflection transect in Arizona: across the transition zone from Colorado Plateau to core complexesEos, Vol. 67, No. 44, Nov. 4th. p. 1096. (abstract.)Colorado Plateau, ArizonaGeophysics, Tectonics
DS1990-1064
1990
Latham, T.Morel-a-l'hussier, P., Green, A. G., Jones, A.G., Latham, T.The crust beneath the intracratonic Williston Basin from geophysical datain: Pinet, B., Bois, C. editors The potential of deep seismic profiling for, pp. 141-160SaskatchewanGeophysics, Williston Basin
DS1992-0319
1992
Latham, T.Culotta, R., Latham, T., Sydow, M., Oliver, J., Brown, L., KaufmanDeep structure of the Texas Gulf passive margin and its Ouachita Precambrian basement: results of the COCORP San Marcos Arch surveyAmerican Association of Petroleum Geologists Bulletin, Vol. 76, No. 2, February pp. 270-285GlobalTectonics, Geophysics -seismics COCORP
DS1988-0406
1988
Latham, T.S.Latham, T.S., Best, J., Chaimov, T., Oliver, J., Brown, L.COCORP profiles from the Montana plains: the Archean cratonic crust And a lower crustal anomaly beneath the Williston basinGeology, Vol. 16, No. 12, December pp. 1073-1076MontanaMantle, Geophysics
DS1860-0898
1895
Latimer, E.W.Latimer, E.W.Europe in Africa in the Nineteenth CenturyChicago: Mcclurg, 451P.Africa, South AfricaHistory
DS1990-0905
1990
Latin, D.Latin, D., White, N.Generating melt during lithospheric extension: pureshear vs. simpleshearGeology, Vol. 18, No. 4, April pp. 327-331GlobalMantle melt, Tectonics -shear
DS1993-0884
1993
Latin, D.Latin, D., Norry, M.J., Tarzey, R.J.E.Magmatism in the Gregory Rift, East Africa: evidence for melt generation bya plume.Journal of Petrology, Vol. 24, No. 5, October pp. 1007-1028.TanzaniaTectonics, Magmatism
DS1992-0911
1992
Latin American InstituteLatin American InstituteThe South American mining guideLatin American Institute, Subscription $ 995.00South AmericaBook -ad, Mining laws, legal
DS1982-0362
1982
Latou, A.Latou, A.Les Gisements de Diamant de la Republique Centraafricaine Dans Leur Contexte Geologique de l'afrique Centrale: Cas Particulier de N'zako.Ph.d. Thesis, University Paris, 114P.West Africa, Central African RepublicOrigin, Diamonds
DS201708-1571
2017
Latouche, C.Fritsch, E., Rondeau, B., Devouard, B., Pinsault, L., Latouche, C.Why are some crystals gem quality? Crystal growth considerations on the 'GEM FACTOR'.The Canadian Mineralogist, Vol. 55, 4, pp. 521-533.TechnologyDeposit - Renard 2

Abstract: The purpose of this work is to investigate the crystal growth parameters necessary or sufficient to obtain a crystal specifically of gem quality. We assume adequate chemistry is available. First, nucleation must occur with only a limited number of nuclei, otherwise too many crystals will be produced, and they will be too small to be faceted into a gem. Two growth mechanisms are readily documented for gems: Most commonly there is slow growth, driven by a spiral growth mechanism, leading to large single individuals. There are only a few examples of fast growth leading to gem-quality edifices: examples include “gota de aceite” Colombian emerald or the dendritic “pseudo cube” for gem diamonds. We have not documented the intermediate conditions between these two extremes in the Sunagawa diagram, which would correspond to 2D nucleation growth. The presence of inclusions is to be limited to desirable ones. Thus, in general, a good stability of the growth interface is the best guarantee of good clarity in the final gem. As for the interface, in general, growth conditions must be relatively stable over the period necessary to achieve growth. Perhaps surprisingly, it has become well documented that gem-quality near-colorless diamonds may have experienced quite a complex growth history. Therefore, the term stability has to be re-defined for each system producing a given gem. The length of time it takes to achieve crystallization of the gem has rarely been studied or estimated. Scientific evidence from experimental petrology and the growth of synthetic gems indicates that it does not take millions of years to grow a gem, but that this exercise may be achieved in a week to, arguably, a few years at the most. Available free space to grow does not appear always necessary, but it helps. Otherwise deformation, inclusions, and other negative effects may occur. Finally, no dramatic post-growth events, such as fracturing or etching, should affect the gem crystal.
DS1994-0988
1994
LaTourette, T.LaTourette, T., Holloway, J.R.Oxygen fugacity of the diamond + C-O fluid assemblage and CO2 fugacity at 8GPa.Earth Planetary Science Letters, Vol. 128, No. 3-4, Dec. pp. 439-452.GlobalDiamond genesis
DS1991-0588
1991
Lattanzi, C.R.Goode, J.R., Davie, M.J., Smith, L.D., Lattanzi, C.R.Back to basics: the feasibility studyThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 84, No. 953, September pp. 53-61GlobalEconomics, Valuation
DS1991-0959
1991
Lattanzi, P.Lattanzi, P.Applications of fluid inclusions in the study and exploration of mineraldepositsEur. Journal of Mineral, Vol. 3, No. 4, pp. 689-701GlobalOre deposits, Fluid inclusions
DS1989-0854
1989
Lattanzi, R.Lattanzi, R.Significant factors in mine valuationThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) 91st. Annual Meeting Preprint, No. 79, 20p. Database # 17962GlobalEconomics, Mine evaluation
DS1910-0069
1910
LatteuxLatteuxAu Pays de L'or et les DiamantParis: Ailland, Alves And Cie, Rio De Janeiro: Francisco, Alvi, 430P.BrazilKimberlite
DS1910-0070
1910
LatteuxLatteuxAu Pays de L'or et des Diamants. a Travers le BresilParis: Ailland, Alves And Cie., 430P.BrazilKimberlite
DS200612-0506
2006
Latti, D.Grutter, H., Latti, D., Menzies, A.Cr saturation arrays in concentrate garnet compositions from kimberlite and their use in mantle barometry.Journal of Petrology, Vol. 47, 4, April pp. 801-820.MantleGeobarometry, chromite, chromium
DS202004-0526
2020
Laturtrie. B.Laturtrie. B., Ross, P-S.Phreatomagmatic vs magmatic eruptive styles in maar-diatremes: a case study at Twin Peaks, Hopi Buttes volcanic field, Navajo Nation, Arizona.Bulletin of Volcanology, Vol. 82, 28.United States, Arizonamagmatism

Abstract: The Hopi Buttes volcanic field (HBVF) is located on the Colorado Plateau, Northern Arizona. In this Miocene volcanic field, the erosion level increases southward, allowing the study of maar-diatreme volcanoes from top (posteruptive crater infill and ejecta ring) to bottom (lower diatreme). The Twin Peaks volcanic complex consists mostly of two hills (North Peak and South Peak) with thick lavas at their summits and pyroclastic rocks underneath. In the HBVF, such volcanic remnants have received little scientific attention so far, despite their relative abundance. Our field observations allow us to interpret the North and South Peaks as remnants of two maar-diatreme volcanoes which evolved into lava lakes filling the craters. Within the complex, we distinguish four volcanic units (from unit 1 at the bottom to unit 4 at the top). On the basis of the field description of the deposits and the componentry measurements, we suggest that unit 1 is phreatomagmatic, unit 2 is phreato-strombolian (with mixed phreatomagmatic and strombolian characteristics), unit 3a is phreato-hawaiian (with mixed phreatomagmatic and hawaiian characteristics), unit 3b is hawaiian (formed by lava fountains) and unit 4 consists of lava lakes filling the maar craters. There is therefore a progressive evolution from a purely phreatomagmatic eruptive style, which excavated the craters and diatremes and partly filled them, to magmatic explosive to nonexplosive eruptive styles, which filled the maar craters up to the pre-eruptive surface. We discuss traditional criteria used to distinguish phreatomagmatic from magmatic eruptive styles in ultramafic to mafic maar-diatreme volcanoes.
DS201903-0526
2019
Latypov, R.Latypov, R., Chisryakova, S., Griev, R., Huhma, H.Evidence for igneous differentiation in Sudbury Igneous Complex and impact driven evolution of Terrestrial planet proto-crusts.Nature Communications, Vol. 10, # 508, pp. 1-13.Canada, Ontariometeorite

Abstract: Bolide impact is a ubiquitous geological process in the Solar System, which produced craters and basins filled with impact melt sheets on the terrestrial planets. However, it remains controversial whether these sheets were able to undergo large-scale igneous differentiation, or not. Here, we report on the discovery of large discrete bodies of melanorites that occur throughout almost the entire stratigraphy of the 1.85-billion-year-old Sudbury Igneous Complex (SIC) - the best exposed impact melt sheet on Earth - and use them to reaffirm that conspicuous norite-gabbro-granophyre stratigraphy of the SIC is produced by fractional crystallization of an originally homogeneous impact melt of granodioritic composition. This implies that more ancient and compositionally primitive Hadean impact melt sheets on the Earth and other terrestrial planets also underwent large-volume igneous differentiation. The near-surface differentiation of these giant impact melt sheets may therefore have contributed to the evolution and lithological diversity of the proto-crust on terrestrial planets.
DS1995-1062
1995
Latypov, R.M.Latypov, R.M.On origin of anorthosites in Pansky Tundra layered intrusion: field evidence (Kola Peninsula)Russian Geology and Geophysics, Vol. 36, No. 3, pp. 49-56Russia, Kola PeninsulaAnorthosites, Layered intrusion
DS1996-0810
1996
Latypov, R.M.Latypov, R.M.Mechanism of the rhythmic layering of the Pana Tundra intrusion, KolaPeninsulaDoklady Academy of Sciences USSR, Vol. 336, pp. 103-107Russia, Kola PeninsulaLayered intrusion
DS1999-0396
1999
Latypov, R.M.Latypov, R.M., Mitrofanov, Alapietti, HalkoahoPetrology of the lower layered horizon of the Western Pansky TundraIntrusion, Kola Peninsula.Petrology, Vol. 7, No. 5, pp. 482-508.Russia, Kola PeninsulaLayered intrusion - not specific to diamonds
DS1999-0397
1999
Latypov, R.M.Latypov, R.M., Mitrofanov, F.P., Alapieti, KaukkonenPetrology of the upper layered horizon of the West Pansky tundra intrusion( Kola Peninsula).Russian Geology and Geophysics, Vol. 40, No. 10, pp. 1413-36.Russia, Kola PeninsulaLayered intrusion
DS2001-0656
2001
Latypov, R.M.Latypov, R.M., Chistakova, S.Yu.Physiochemical aspects of magnetite gabbro formation in the layered intrusion of the Western Pansky Tundra.Petrology, Vol. 9, No. 1, pp. 25-45.Russia, Kola PeninsulaLayered intrusion
DS1999-0142
1999
Latysh, N.Condie, K.C., Latysh, N., Selverstone, J.Geochemistry, neodymium and Strontium isotopes and uranium-lead (U-Pb) zircon ages of granitoid metasedimentary xenoliths from Navajo...Chemical Geology, Vol. 156, No. 1-4, Apr. 1, pp. 95-134.Arizona, New Mexico, Colorado, WyomingFour Corners area, Navajo volcanic field, Xenoliths
DS201312-0869
2012
Latyshev, A.V.Sonin, V.M., Chepurov, A.A., Shcheglov, D.V., Kosolobov, S.S., Logvinova, A.M., Chepurov, A.I., Latyshev, A.V., Sobolev, N.V.Study of the surface of natural diamonds by the method of atomic force microscopy.Doklady Earth Sciences, Vol. 447, 2, pp. 1314-1316.TechnologyDiamond morphology
DS201709-1972
2017
Latyshev, A.V.Chepurov, A.A., Kosolobov, S.S., Shcheglov, D.V., Sonin, V.M., Chepurov, A.I., Latyshev, A.V.Nanosculptures on round surfaces of natural diamonds.Geology of Ore Deposits, Vol. 59, 3, pp. 256-264.Russiadeposit - Udachnaya -East

Abstract: The results of a study using scanning electron microscopy and atomic force microscopy comprising the micromorphology of the ditrigonal and trigonal layers on surfaces near the edges of octahedral diamond crystals from the Udachnaya-Eastern kimberlite pipe in Yakutia are presented. The studied surface sculptures are elongated parallel to the direction <111> and have similar morphological features, characterized by a wavy profile across the lamination, the absence of flat areas at the micro- and nanolevel. It is proposed that both sculpture types were formed as a result of dissolution under natural conditions. This suggestion is corroborated by the revelation of negative trigons on the octahedral facets of the studied diamonds.
DS202003-0348
2020
Lau, D.Lee, C.W.Y., Cheng, J., Yium Y.C., Chan, K., Lau, D., Tang, W.C., Cheng, K.W,m Kong, T., Hui, T.K.C., Jelezko, F.Correlation between EPR spectra and coloration of natural diamonds.Diamond & Related Materials, Vol. 103, 13p. PdfGlobaldiamond colour

Abstract: White diamonds color grading is one of the basic diamond evaluations. The color value based on a scale that ranges from D to Z, with D being the more colorless and more valuable, among other qualifications. As the diamond grade moves on this scale, its color appears more yellow progressively. This yellowish color, present only in Type I diamonds, is mainly due to the nitrogen related defects such as N3 center and C-center. The current color grading system is based on a visual method, where gemologist compares the sample with a Master Color set. However, this method is very subjective. Several defects responsible for light absorption in diamond are carrying electron spin and appear in Electron Paramagnetic Resonance (EPR) spectrum. In this study, we developed a new EPR based technique for a quantitative measurement of N3 center and C-center in diamond through quantitative EPR spectroscopy. The correlation between EPR spectra and color grades of diamond was established.
DS2001-0701
2001
Lau, H.Louden, K., Lau, H.Insights from scientific drilling on rifted continental marginsGeoscience Canada, Vol.28, 4, Dec. pp.187-95.GreenlandTectonics - rifting, breakup
DS202011-2049
2020
Lau, H.Lau, H., Holtzman, B., Havlin, C.Towards a self-consistent characterization of lithospheric plates using full-spectrum viscoelasticity.AGU Advances, dor.or/10.101029 /2020AV000205Mantletectonics

Abstract: On Earth, broken, rigid tectonic plates lie atop slowly flowing mantle rock (over millions to billions of years). A basic understanding of the global variation in thickness of this rigid lid provides the foundation to many geodynamical predictions. However, using different techniques to estimate its thickness, for example, seismic wave propagation (acting on timescales of seconds), to the warping of plates under the weight of volcanoes (acting on timescales of millions of years) reveals many inconsistencies. At the heart