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Doklady Earth Sciences - The experimental data on diamond growth in the Fe–Ni–S–C and Fe–S–C systems with a sulfur content of 5–14 wt % at 5.5 GPa and... 相似文献
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V.?M.?SoninEmail author E.?I.?Zhimulev B.?S.?Pomazanskiy A.?L.?Zemnuhov A.?A.?Chepurov V.?P.?Afanasiev A.?I.?Chepurov 《Geology of Ore Deposits》2018,60(1):82-92
An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe0.7S0.3) with high P–T parameters (4 GPa, 1400°С) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts. 相似文献
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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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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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The results of experimental modeling of the conditions of crystallization of high-Ca chromium garnets in the system serpentine–chromite–Ca-Cr-bearing hydrous fluid at a pressure of 5 GPa and temperature of 1300°С are reported. The mineral association including quantitatively predominant high-Mg olivine and diopside-rich clinopyroxene, bright-green garnet, and newly formed chrome spinel was formed. Garnet mostly crystallized around primary chromite grains and was characterized by a high concentration of CaO and Cr2O3. According to the chemical composition, garnets obtained are close to the uvarovite–pyrope varieties, which enter the composition of relatively rare natural paragenesis of garnet wehrlite. The experimental data obtained clearly show that high-Ca chromium garnets are formed in the reaction of chromite-bearing peridotite and Ca-rich fluid at high P–T parameters.
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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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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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