共查询到9条相似文献，搜索用时 31 毫秒
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正Kimberlite and lamproite,the major source of diamonds,are volatile-rich potassic ultramafic rocks that originate from the deep lithospheric mantle.These rocks are important for deciphering the composition and 相似文献
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A. M. Logvinova R. Wirth D. A. Zedgenizov L. A. Taylor 《Geochemistry International》2018,56(4):283-291
An aragonite inclusion in natural diamond was identified using techniques of transmission electron microscopy, electron microdiffraction, and microprobe analysis. The inclusion is hosted in a colorless octahedral diamond crystal from the Komslomolskaya pipe in Yakutia. The diamond crystal shows a zoned distribution of its admixtures and defects. The structure parameters of the inclusion (∠[001]/[201] = 66° and certain lattice spacings) correspond to the calculated parameters of the orthorhombic unit cell of a Ca carbonate polymorph. The aragonite inclusion contains admixtures of MgO (0.81), MnO (0.58), and FeO (0.13 wt %). The find of a syngenetic aragonite inclusion in diamond is unique and proves that diamond can be formed in carbonatized mantle peridotite at depths of at least 300 km. The inclusion hosts identifiable microphases of Ni-rich sulfides (37–41 wt % Ni), titanite, hydrous silicate, magnetite, and fluid. This association indicates that the diamond and aragonite crystallized from a carbonate–silicate–sulfide melt or highdensity fluid. 相似文献
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Late Devonian Diamondiferous Kimberlite and Alkaline Picrite (Proto-kimberlite?) Magmatism in the Arkhangelsk Region, NW Russia 总被引：7，自引：4，他引：3
MAHOTKIN I. L.; GIBSON S. A.; THOMPSON R. N.; ZHURAVLEV D. Z.; ZHERDEV P. U. 《Journal of Petrology》2000,41(2):201-227
Widespread penecontemporaneous igneous activity affected NWRussia (the Kola Peninsula and adjoining areas to the SE aroundArkhangelsk) during the Late Devonian (360–380 Ma). Magmatismvaries from tholeiitic basalts, erupted in the axial regionsof former Middle Proterozoic (Riphean) rifts, to strongly alkalinerock-types on and marginal to Archaean cratons. NNE of Arkhangelskkimberlites, olivine lamproites and alkaline picrites were emplaced;all these rock-types are diamondiferous to varying extents.Higher TiO2 (and also total Fe) distinguish predominantly mica-poorEastern Group kimberlites (TiO2 = 2·4–3·1wt %) and spatially associated alkaline picrites (TiO2 = 3·2–3·7wt %) from nearby micaceous Western Group kimberlites (TiO2= 0·8–1·1 wt %). Each rock-type also hasdistinctive rare earth element (REE) patterns, and 相似文献
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P. Ramesh CHANDRA PHANI 《《地质学报》英文版》2016,90(Z1):191-191
正Utility of geochemistry in mineral exploration is known since more than half-a-century.In reconnaissance diamond exploration,regolith geochemistry is a well known tool worldwide and helps in distinguishing bedrock 相似文献
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Yakovlev I. V. Malkovets V. G. Gibsher A. A. Dymshits A. M. Kuzmin D. V. Danilovskaya V. A. Milaushkin M. V. Pokhilenko N. P. Sobolev N. V. 《Doklady Earth Sciences》2022,506(1):635-640
Doklady Earth Sciences - Novel data from mineralogical studies of the peridotite xenoliths from the Komsomol’skaya–Magnitnaya kimberlite pipe, Upper Muna field, Siberian craton, are... 相似文献
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Sharygin I. S. Golovin A. V. Dymshits A. M. Kalugina A. D. Solovev K. A. Malkovets V. G. Pokhilenko N. P. 《Doklady Earth Sciences》2021,500(2):842-847
Doklady Earth Sciences - The results of study secondary crystallized melt inclusions in olivine of a sheared peridotite xenolith from the Komsomolskaya–Magnitnaya kimberlite pipe (Upper Muna... 相似文献
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The 642 Ma-old Brauna Kimberlite Field is located on the northeastern sector of the São Francisco Craton (Serrinha block) and is one of the rare Neoproterozoic kimberlitic events in South America. Zircon xenocrysts from the volumetric most important kimberlite pipes Brauna 03, Brauna 07 and Brauna 04 were used as a tool to identify different components of the lithosphere beneath the northeast region of the São Francisco craton. A composite kimberlite sample of eight representative and different drill holes and three samples of the host rocks (Nordestina granodiorite) were sampled for SHRIMP geochronology. The results were compared with precise U–Pb age data for the regional rocks, i.e. the Archaean basement and the Palaeoproterozoic Rio Itapicuru greenstone belt. Samples from the Nordestina granodiorite gave three different ages: 2155 Ma in the western part of the batholith, 2139 Ma in its central part, and 2132 Ma in its eastern part. Zircon 207Pb/206Pb ages of the Brauna kimberlite zircon grains spread over the timespan 2107–2223 Ma and indicate four age groups at 2105 ± 3 Ma, 2138 ± 7 Ma, 2166 ± 5 Ma, and 2198 ± 4 Ma. Source rocks for the three former age groups can be found in the Rio Itapicuru greenstone belt, including zircon xenocrysts from the Nordestina granodiorite, whereas the latter age group has not yet been reported in the Serrinha block. The new zircon ages show that only rocks of the Palaeoproterozoic Rio Itapicuru greenstone belt and of a hidden 2.17–2.20 Ga crust were sampled by the kimberlite magma during its ascent through the lithosphere. It is proposed that there is none or a few Archaean crust beneath the kimberlite emplacement area, hence implying a thick Palaeoproterozoic lithosphere for this portion of the São Francisco craton. 相似文献
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Yu. O. Larionova L. V. Sazonova N. M. Lebedeva A. A. Nosova V. V. Tretyachenko A. V. Travin A. V. Kargin D. S. Yudin 《Petrology》2016,24(6):562-593
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. 相似文献