Evidence for the suprasubduction origin of mantle section rocks of Voykar ophiolite,Polar Urals     

Belousov  I. A.  Batanova  V. G.  Savelieva  G. N.  Sobolev  A. V. 《Doklady Earth Sciences》2009,429(1):1394-1398

Doklady Earth Sciences -  相似文献   

Experimental testing of olivine–melt equilibrium models at high temperatures     

S.?P.?KrasheninnikovEmail author  A.?V.?Sobolev  V.?G.?Batanova  A.?A.?Kargaltsev  A.?A.?Borisov 《Doklady Earth Sciences》2017,475(2):919-922

Data are presented on the equilibrium compositions of olivine and melts in the products of 101 experiments performed at 1300–1600°C, atmospheric pressure, and controlled oxygen fugacity by means of new equipment at the Vernadsky Institute. It was shown that the available models of the olivine–melt equilibrium describe with insufficient adequacy the natural systems at temperatures over 1400°C. The most adequate is the model by Ford et al. (1983). However, this model overestimates systematically the equilibrium temperature with underestimating by 20–40°C at 1450–1600°C. These data point to the need for developing a new, improved quantitative model of the olivine–melt equilibrium for high-temperature magnesian melts, as well as to the possibility of these studies on the basis of the equipment presented.  相似文献   

Isotope compositions of C and O of magmatic calcites from the Udachnaya–East pipe kimberlite,Yakutia     

Tomilenko  A. A.  Dublyansky  Yu. V.  Kuzmin  D. V.  Sobolev  N. V. 《Doklady Earth Sciences》2017,475(1):828-831

It has been demonstrated for the first time that the isotopic compositions of carbon (δ¹³C) in magmatic calcites from the Udachnaya–East pipe kimberlite groundmass varies from–2.5 to–1.0‰ (V-PDB), while those of oxygen (δ¹⁸O) range from 15.0 to 18.2‰ (V-SMOW). The obtained results imply that during the terminal late magmatic and postmagmatic stages of the kimberlite pipe formation, the carbonates in the kimberlite groundmass became successively heavier isotopically, which indicates the hybrid nature of the carbonate component of the kimberlite: it was formed with contributions from mantle and sedimentary marine sources.

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Primary melt and fluid inclusions in regenerated crystals and phenocrysts of olivine from kimberlites of the Udachnaya-East Pipe,Yakutia: The problem of the kimberlite melt     

Tomilenko  A. A.  Kuzmin  D. V.  Bul’bak  T. A.  Sobolev  N. V. 《Doklady Earth Sciences》2017,475(2):949-952

The primary melt and fluid inclusions in regenerated zonal crystals of olivine and homogeneous phenocrysts of olivine from kimberlites of the Udachnaya-East pipe, were first studied by means of microthermometry, optic and scanning electron microscopy, electron and ion microprobe analysis (SIMS), inductively coupled plasma mass-spectrometry (ICP MSC), and Raman spectroscopy. It was established that olivine crystals were regenerated from silicate–carbonate melts at a temperature of ~1100°C.

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Polarization of radiation in the case of multiple scattering in a plane layer     

V. M. Loskutov  V. V. Sobolev 《Astrophysics》1981,17(3):299-306

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Petrogenesis of group A eclogites and websterites: evidence from the Obnazhennaya kimberlite,Yakutia     

Lawrence?A.?TaylorEmail author  Gregory?A.?Snyder  Randall?Keller  David?A.?Remley  Mahesh?Anand  Rene?Wiesli  John?Valley  Nikolai?V.?Sobolev 《Contributions to Mineralogy and Petrology》2003,145(4):424-443

Mantle xenoliths from the Obnazhennaya kimberlite pipe, Yakutia, possess a large range of mineralogical and chemical compositions, from both group A and B eclogites. Major-element contents of the group A eclogites exhibit transitional features between the group B eclogites and peridotite. The Mg# of clinopyroxenes is 0.86–0.94, with 0.60–0.84 for garnets. Differences in concentration of LREEs exist between the Obnazhennaya group A and the well-studied group B eclogites from the Udachnaya kimberlite pipe. In general, garnets in the group A eclogites contain lower LREEs than those from the group B eclogites; however, the trend for clinopyroxene is reversed. High d ¹⁸O (5.46–7.81) values, and the positive Eu anomalies in the garnets and clinopyroxenes (Eu/Eu* 1.2–1.4) demonstrate the involvement of an oceanic crustal component in the formation of the group A eclogites. The group A eclogites formed between 21.0 and 37.6 kbar, and 711 and 923 °C, in a time interval of 1,071–1,237 Ma. An innovative model is proposed to explain the formation of the group A eclogites and websterites. It involves the reaction of a depleted mantle peridotite with TTG and carbonatite melts closely related to the subduction of oceanic crust.  相似文献   

Long- and short-term earthquake prediction in Kamchatka   总被引：1，自引：0，他引：1  

S.A. Fedotov  G.A. Sobolev  S.A. Boldyrev  A.A. Gusev  A.M. Kondratenko  O.V. Potapova  L.B. Slavina  V.D. Theophylaktov  A.A. Khramov  V.A. Shirokov 《Tectonophysics》1977,37(4):305-321

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Coexisting garnets and ilmenites synthesized at high pressures from pyrolite and olivine basanite and their significance for kimberlitic assemblages     

D. H. Green  N. V. Sobolev 《Contributions to Mineralogy and Petrology》1975,50(3):217-229

Coexisting garnets and ilmenites have been synthesized at high pressure (21–40 kb) within the temperature range between 900 and 1100 °C from pyrolite-less-40% olivine and olivine basanite with various water contents. The two compositions yield phases with a range in the 100 Mg/Mg+Fe ratio for both garnet (41–76) and ilmenite (15–47). The distribution coefficient for iron and magnesiaum (K _{D(Fe, Mg)} ^ilm-ga = 4.0±0.5) for coexisting phases does not appear to vary with change in the bulk composition or temperature of synthesis. The synthesized ilmenites are of similar composition to those of kimberlites in 100 Mg/Mg+Fe ratio and Al₂O₃ and Cr₂O₃ solid solution. Cr₂O₃ content in ilmenite is dependent on Cr₂O₃ in the bulk composition and also on Fe₂O₃ content of ilmenite. Fe₂O₃ content of ilmenite is very sensitive to f _O2 and natural ilmenites from peridotites have formed under low f _O2. Al₂O₃ solid solution in ilmenite as well as TiO₂ in coexisting garnet tend to be higher with higher temperature. All the variety of compositions of ilmenites from kimberlites may be obtained from rocks rather close in composition to those used in experiments, within the same range of pressure and temperature but at variable oxygen fugacities.  相似文献   

Theory of flare stars     

V. P. Grinin  V. V. Sobolev 《Astrophysics》1977,13(4):348-357

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Crystalline inclusions and C isotope ratios in diamonds from the Snap Lake/King Lake kimberlite dyke system: evidence of ultradeep and enriched lithospheric mantle   总被引：5，自引：0，他引：5  

N.P. Pokhilenko  N.V. Sobolev  V.N. Reutsky  A.E. Hall  L.A. Taylor 《Lithos》2004,77(1-4):57-67

U-type paragenesis inclusions predominate (94.7%) among the crystalline inclusion suite of 115 diamonds (−4+2 mm) obtained from the recently discovered Snap Lake/King Lake (SKL) kimberlite dyke system, Southern Slave, Canada. The most common inclusions are olivine (90) and enstatite (22). Sulfide, Cr-pyrope, chromite and Cr-diopside inclusion are less abundant (15, 10, 5 and 1, respectively). Results of the inclusion composition study demonstrate the following. (a) The relatively enriched character of the mantle parent rocks of the U-type diamonds. The average Mg# of olivine inclusions is 92.1, and of enstatite inclusions average 93.3. CaO content in Cr-pyrope inclusions is relatively high (3.73–5.75 wt.%). (b) Four of ten U-type Cr-rich pyrope inclusions contain a majoritic component up to 16.8 mol.% which requires pressures of 110 kbar. Carbon isotopes compositions for 34 diamonds with U-type inclusions have a δ¹³C range from −3.2‰ to −9‰ with a strong peak around −3.5‰. This is much heavier than the ratios of U-type diamonds from Siberia and South Africa (4.5‰). Diamonds with olivine inclusions can be divided into two groups based on their δ¹³C values as well as the Mg# and Ni/Fe ratio in the olivines. Most show a narrow range of δ¹³C values from −3.2‰ to −4.8‰ (average −3.72‰) and have olivine inclusions with Mg# less than 92.3 and relatively high Fe/Ni ratios. A second group is characterized by a much wider variation of C isotope composition (δ¹³C varies from −3.8‰ to −9.0‰, average −5.97‰), and the olivine inclusions having a higher Mg# (up to 93.6) and relatively low Fe/Ni ratios. This difference in the C isotope composition may have several explanations: (a) peculiarities of asthenosphere degassing coupled with an abnormal thickness of lithosphere; (b) the abnormal thickness and enriched character of lithospheric mantle; (c) involvement of subducted C of crustal origin in the processes of the diamond formation. The presence of subcalcic Cr-rich majorite (up to 17 mol.%) pyropes of low-Ca harzburgite paragenesis among the crystalline inclusion suite of SKL diamonds is strong evidence for the existence of diamondiferous depleted peridotite in lithospheric mantle at depth near 300 km beneath Southern Slave area and is postulated to be one of the main reasons for the much heavier C isotope composition of SKL U-type diamonds in comparison with those from Siberian and South African kimberlites.  相似文献