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Chepurov A. I. Zhimulev E. I. Sonin V. M. Chepurov A. A. Karpovich Z. A. Goryainov S. V. Afanasiev V. P. Pokhilenko N. P. 《Doklady Earth Sciences》2021,500(1):734-737
Doklady Earth Sciences - Experimental results on the growth of cubic diamond on lonsdaleite-bearing diamonds from the Popigai astrobleme at 5.5 GPa and 1450°C in the Fe–Ni–C system... 相似文献
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Chepurov A. I. Sonin V. M. Zhimulev E. I. Chepurov A. A. Tomilenko A. A. 《Doklady Earth Sciences》2011,441(2):1738-1741
This work presents data on the experimental study of CaCO3 stability (3.0–5.5 GPa; 1300–1400°C) under reducing conditions modeling the presence of metallic iron. It is established
that CaCO3 is stable at the above P-T parameters under reducing conditions (in the presence of metallic Ti). CaCO3 decomposed only when it chemically interacted with iron, forming Ca-ferrites and releasing solid carbon in the form of graphite
in the closed system (in sealed Pt-ampoules). 相似文献
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Cuboctahedral diamond monocrystals of physical classification type IIb weighing from 0.1 to 2 carats and with minor faces {110}, {311}, and {511} have been synthesized. The crystals are characterized by various hues of blue and dark blue depending on the amount of B in the system. A characteristic feature of these diamonds is a sectorial structure expressed in a nonuniform color distribution. The following types of metallic inclusions in the crystals have been recognized: faceted isometric, lamellar, and extended inclusions; unfaceted irregular and drop-shaped inclusions; and microinclusions. These inclusions are related to the chemical composition of the metal solvent. 相似文献
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A. A. Chepurov S. S. Kosolobov D. V. Shcheglov V. M. Sonin A. I. Chepurov A. V. Latyshev 《Geology of Ore Deposits》2017,59(3):256-264
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. 相似文献
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Glauconite segregations in Oligocene–Miocene shelf sediments of Western Kamchatka (Kakert and Gakkha horizons) are studied. Glauconite occurs in the studied samples as morphologically different grains, finely dispersed cement, and pseudomorphoses after organogenic structures (siliceous sponge spicules, diatom algae frustules, and others). In addition, samples of the clasts of bryozoans, volcanic glass, and terrigenous grains revealed for the first time traces of the boring algae similar to recent species of genus Hyella and, possibly, Dalmatella, whose tubules are sometimes filled with the finely dispersed glauconite. Our data based on the detailed petrographic studies and SEM investigations confirm and supplement the opinion of several researchers about an important role of microbiota on the glauconite formation. The paper discusses different stages of the glauconite formation in sediments of the Kakert and Gakkha horizons and the possible setting of glauconite infilling in the algal borer trails and holes. 相似文献
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A.I. Chepurov E.I. Zhimulev L.V. Agafonov V.M. Sonin A.A. Chepurov A.A. Tomilenko 《Russian Geology and Geophysics》2013,54(4):406-415
It is generally accepted that the composition of ultrabasic nodules and their quantitative proportions do not significantly change during their transportation with kimberlitic magma to the Earth’s surface. We performed an experimental study of the relative stability of olivine, garnet, and pyroxenes in kimberlite melt at high pressure and temperatures (4 GPa, 1300–1500 °C). The study has shown that the loss in weight of minerals and, correspondingly, the rate of their dissolution in kimberlite melt differ considerably. The following sequence of the dissolution rates of minerals has been established: Cpx ≥ Opx > Gar > Ol. Pyroxenes are characterized by the most rapid dissolution, and olivine is the most stable mineral. The assumption is made that clinopyroxenites and websterites disintegrate more rapidly than dunites and lherzolites in kimberlitic magma. 相似文献
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Diamond crystallization in the Fe-Co-S-C and Fe-Ni-S-C systems and the role of sulfide-metal melts in the genesis of diamond 总被引：1，自引：0，他引：1
E. I. Zhimulev A. I. Chepurov E. F. Sinyakova V. M. Sonin A. A. Chepurov N. P. Pokhilenko 《Geochemistry International》2012,50(3):205-216
Diamond crystals 0.1–0.8 carats were synthesized in experiments conducted in a BARS split-sphere multianvil high-pressure
apparatus in the systems Fe-Co-S-C and Fe-Ni-S-C at a pressure of 5.5 GPa and temperature of 1300°C. The microtextures of
the samples and the phases accompanying diamond (carbides, graphite, monoslufide solid solution, pentlandite, and taenite)
are examined in much detail, the properties of metal-sulfide-carbon alloys are discussed, and issues related to the genesis
of sulfide inclusions in diamonds and graphite crystallization in the diamond stability field are considered. The experiments
demonstrate that diamonds can be synthesized and grow in pre-eutectic metal-sulfide melts with up to 14 wt % sulfur at relatively
low P-T parameters, which correspond to the probable temperatures and pressures of natural diamond-forming processes at depths of
approximately 150 km in the Earth’s upper mantle. 相似文献
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