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Alakit and Daldyn kimberlite fields,Siberia,Russia:Two types of mantle sub-terranes beneath central Yakutia?

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Geoscience Frontiers 2017年第4期8卷 671-692页

作者： I.V.Ashchepkov a.m.logvinova T.Ntaflos N.V.Vladykin S.I.Kostrovitsky Z.Spetsius S.I.mityukhin S.A.Prokopyev N.S.medvedev H.Downes Institute of Geology and mineralogy SD RAS Institute of Geochemistry SD RAS Dept.of Lithospheric Research University of Vienna Alrosa Stock Company Nikolaev Institute of Inorganic Chemistry 3 Department of Earth and Planetary Sciences Birkbeck University of London

mineral data from Yakutian kimberlites allow reconstruction of the history of lithospheric *** occur in compositions of mantle pyropes and clinopyroxenes from large kimberlite pipes in the Alakit and Daldyn *** the Alakit ***-diopsides are alkaline,and Stykanskaya and some other pipes contain more sub-calcic pyropes and dunitic-type diamond inclusions,while in the Daldyn field harzburgitic pyropes are *** eclogitic diamond inclusions in the Alakit field are sharply divided in types and conditions,while in the Daldyn field they show varying compositions and often continuous Pressure-Temperature（P-T） ranges with increasing Fe~# with decreasing *** Alakit,Crpargasites to richterites were found in all pipes,while in Daldyn,pargasites are rare Dalnyaya and Zarnitsa ***-diopsides from the Alakit region show higher levels of light Rare Earth Elements（LREE）and stronger REE-slopes,and enrichment in light Rare Earth Elements（LREE）,sometimes Th-U,and small troughs in *** the Daldyn field,the High Field Strength Elements HFSE troughs are more common in clinopyroxenes with low REE abundances,while those from sheared and refertilized peridotites have smooth *** from Alakit show HREE minima,but those from Daldyn often have a trough at Yand high U and ***/O2 diagrams from both regions show similarities,suggesting similar layering and *** degree of metasomatism is often higher for pipes which show dispersion in P-Fe~# trends for *** the mantle beneath Udachnaya and Aykhal,pipes show 6-7 linear arrays of P-Fe~# in the lower part of the mantle section at 7.5-3.0 GPa,probably reflecting primary subduction *** the Sytykanskaya pipe,there are several horizons with opposite inclinations which reflect metasomatic *** high dispersion of the P—Fe~# trend indicating widespread metasomatism is associated with decreased diamond *** explanation of the differences in miner

关键词： Thermobarometry Geochemistry Daldyn Alakit Craton Lithosphere

The Sytykanskaya kimberlite pipe:Evidence from deep-seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit,Yakutia,Russia

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Geoscience Frontiers 2015年第5期6卷 687-714页

作者： I.V.Ashchepkov a.m.logvinova L.F.Reimers T.Ntaflos Z.V.Spetsius N.V.Vladykin H.Downes D.S.Yudin A.V.Travin L.V.makovchuk V.S.Palesskiy O.S.Khmel'nikova Institute of Geology and mineralogy SB RAS Vienna University Alrosa Stock Company Institute of Geochemistry SB RAS Birkbeck College University of LondonUKMalet Street

mantle xenoliths（>150） and concentrates from late autolithic breccia and porphyritic kimberlite from the Sytykanskaya pipe of the Alakit field（Yakutia） were analyzed by EPmA and LAm ICP *** P-TX-f（O2） diagrams minerals from xenoliths show widest variations,the trends P-Fe#-CaO,f（O2）for minerals from porphyric kimberlites are more stepped than for xenocrysts from *** PTX points mark moving for protokimberlites from the lithosphere base（7.5 GPa） to pyroxenite lens（5-3.5 GPa） accompanied by Cr increase by AFC and creation of two trends P-Fe#OI10-12%and13-15%.The Opx-Gar-based mantle geotherm in Alakit field is close to 35 mW/m2 at 65 GPa and 600 C near moho was *** oxidation state for the megacrystalline ilmenites is lower for the metasomatic associations due to reduction of protokimberlites on peridotites than for uncontaminated varieties at the lithosphere *** inclined linear REE patterns with deep HFSE troughs for the parental melts of clinopyroxene and garnet xenocrysts from breccia were influenced by differentiated *** for metasomatic xenoliths reveal less inclined slopes without deep troughs in spider *** reveal S-shaped REE *** clinopyroxenes from graphite bearing Cr-websterites show inclined and inflected in Gd spectrums with LREE variations due to AFC *** for garnets display less inclined patterns and Ba-Sr troughs but enrichment in ***40Ar/39Ar ages for micas from the Alakit mantle xenoliths for disseminated phlogopites reveal Proterozoic（1154 ma） age of metasomatism in early Rodinia *** glimmerites with richterite- like amphiboles mark1015 ma plume event in Rodinia ***600-550 ma stage manifests final Rodinia *** last 385 ma metasomatism is protokimberlite-related.

关键词： Kimberlites mantle lithosphere mantle xenoliths Th

Thermobarometry of Inclusions: Implications to the Structure of Lithospheric mantle and Evolution in Time and Diamond Formation

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Acta Geologica Sinica(English Edition) 2021年第S1期95卷 18-21页

作者： Igor V.ASHCHEPKOV Alla.m.logvinova Zdislav V.SPETSIUS V.S.Sobolev Institute of Geology and mineralogy SB RAS Novosibirsk 630090Russia Alrosa Stock Company Mirny 678174Russia

Thermobarometric calculations for mineral diamond inclusions and associations(DIA)provide a systematic comparison of PTXFO2 conditions for different cratons worldwide,using a database of 4440 mineral EPmA analyses(Ash... 详细信息

关键词： diamond inclusions craton garnet clinopyrogene orthopyroxene geothermal regime manle lithosphere

Composition of Hydrocarbons in Diamonds, Garnet, and Olivine from Diamondiferous Peridotites from the Udachnaya Pipe in Yakutia, Russia

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Engineering 2019年第3期5卷 471-478页

作者： Nikolay V. Sobolev Anatoly A. Tomilenko Taras A. Bul’bak Alla m. logvinova V.S. Sobolev Institute of Geology and mineralogy Siberian Branch of the Russian Academy of Sciences Novosibirsk 630090 Russia Department of Geology and Geophysics Novosibirsk State University Novosibirsk 630090 Russia

Volatile components in diamonds, associated garnet (pyrope), and olivine from two extremely rare xenoliths of diamondiferous peridotites recovered from the Udachnaya kimberlite pipe in Yakutia, Russia, were analyzed by gas chromatography–mass spectrometry (GC–mS) using a Focus DSQ II Series Single Quadrupole GC–mS (Thermo Scientific, USA). These xenoliths are pyrope lherzolite and pyrope dunite based upon compositions of coexisting minerals. Unlike the pyrope lherzolite, which contained pyrope with moderate calcium (Ca)-component content (about 15 mol%), the dunite contained subcalcic chromium (Cr)-pyrope with low Ca-component content (less than 10 mol%). All investigated minerals contained dominating hydrocarbons and their derivatives represented by aliphatic (paraffins, olefins), cyclic (naphthenes, arenes), oxygenated (alcohols, ethers), and heterocyclic (dioxanes, furans) hydrocarbons;nitrogenated, chlorinated, and sulfonated compounds;carbon dioxide (CO2);and water (H2O). The relative concentration (rel%) of total hydrocarbon was 79.7 rel% for diamonds, 69.1 rel% for garnet, and 92.6 rel% for olivine, with a general amount of components ranging from 161 to 206. New data on volatiles in diamonds, associated garnet, and olivine suggest the presence of a wide spectrum of hydrocarbons along with nitrogen (N2), CO2, and H2O in some upper mantle areas.

关键词： Diamond Volatiles Hydrocarbons Pyrope Olivine Inclusions