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1.
Melt inclusions were examined in phenocrysts in basalt, andesite, dacite, and rhyodacite from the Karymskii volcanic center in Kamchatka and dacite form Golovnina volcano in Kunashir Island, Kuriles. The inclusions were examined by homogenization and by analyzing glasses in more than 80 inclusions on an electron microscope and ion microprobe. The SiO2 concentrations in the melt inclusions in plagioclase phenocrysts from basalts from the Karymskii volcanic center vary from 47.4 to 57.1 wt %, these values for inclusions in plagioclase phenocrysts from andesites are 55.7–67.1 wt %, in plagioclase phenocrysts from the dacites and rhyodacites are 65.9–73.1 wt %, and those in quartz in the rhyodacites are 72.2–75.7 wt %. The SiO2 concentrations in melt inclusions in quartz from dacites from Golovnina volcano range from 70.2 to 77.0 wt %. The basaltic melts are characterized by usual concentrations of major components (wt %): TiO2 = 0.7–1.3, FeO = 6.8–11.4, MgO = 2.3–6.1, CaO = 6.7–10.8, and K2O = 0.4–1.7; but these rocks are notably enriched in Na2O (2.9–7.4 wt % at an average of 5.1 wt %, with the highest Na2O concentration detected in the most basic melts: SiO2 = 47.4–52.0 wt %. The concentrations of volatiles in the basic melts are 1.6 wt % for H2O, 0.14 wt % for S, 0.09 wt % for Cl, and 50 ppm for F. The andesite melts are characterized by high concentrations (wt %) of FeO (6.5 on average), CaO (5.2), and Cl (0.26) at usual concentrations of Na2O (4.5), K2O (2.1), and S (0.07). High water concentrations were determined in the dacite and rhyodacite melts: from 0.9 to 7.3 wt % (average of 15 analyses equals 4.5 wt %). The Cl concentration in these melts is 0.15 wt %, and those of F and S are 0.06 and 0.01 wt %, respectively. Melt inclusions in quartz from the dacites of Golovnina volcano are also rich in water: they contain from 5.0 to 6.7 wt % (average 5.6 wt %). The comparison of melt compositions from the Karymskii volcanic center and previously studied melts from Bezymyannyi and Shiveluch volcanoes revealed their significant differences. The former are more basic, are enriched in Ti, Fe, Mg, Ca, Na, and P but significantly depleted in K. The melts of the Karymskii volcanic center are most probably less differentiated than the melts of Bezymyannyi and Shiveluch volcanoes. The concentrations of water and 20 trace elements were measured in the glasses of 22 melt inclusions in plagioclase and quartz from our samples. Unusually high values were obtained for Li concentrations (along with high Na concentrations) in the basaltic melts from the Karymskii volcanic center: from 118 to 1750 ppm, whereas the dacite and rhyolite melts contain 25 ppm Li on average. The rhyolite melts of Golovnina volcano are much poorer in Li: 1.4 ppm on average. The melts of the Karymskii volcanic center are characterized by relative minima at Nb and Ti and maxima at B and K, as is typical of arc magmas. 相似文献
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Platinum-group minerals (PGM) in primary ores and placers are compared in order to substantiate prospecting guides for layered
and differentiated intrusions containing sulfide Cu-Ni ores with platinum-group elements (PGE). It is shown that supergene
placer mineral assemblages bear information on primary sources and their probable economic value. The mineralogical and geochemical
data on the large Siberian intrusions that host Cu-Ni and low-sulfide PGM deposits (Noril’sk 1, Kingash, Chinei, and Yoko-Dovyren)
are used to elaborate mineralogical prospecting guides based on the comparative study of PGM assemblages in primary ore, heavy
concentrate halos, and hillside sediments. The mechanism of PGM redistribution under supergene conditions is exemplified in
the Chinei deposit. The placer mineral assemblage with prevalence of Pt-Fe alloys, atokite-rustenburgite, sperrylite, and
multicomponent Pd-Sn-Cu-Pb compounds can be used as a prospecting guide for Noril’sk-type primary PGM ore and related economic
placers. The paolovite-sperrylite or sperrylite PGM assemblage in heavy concentrate halos indicates occurrence of Cu-Ni ore
in the prospecting area. Sperrylite with isomorphic admixture of Ir and Os typical of the Kingash pluton could be a orospecting
guide for Ni-bearing mafic-ultramafic intrusions. 相似文献
3.
M. A. Tolstykh N. A. Diansky A. V. Gusev D. B. Kiktev 《Izvestiya Atmospheric and Oceanic Physics》2014,50(2):111-121
A coupled atmosphere-ocean model intended for the simulation of coupled circulation at time scales up to a season is developed. The semi-Lagrangian atmospheric general circulation model of the Hydrometeorological Centre of Russia, SLAV, is coupled with the sigma model of ocean general circulation developed at the Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), INMOM. Using this coupled model, numerical experiments on ensemble modeling of the atmosphere and ocean circulation for up to 4 months are carried out using real initial data for all seasons of an annual cycle in 1989–2010. Results of these experiments are compared to the results of the SLAV model with the simple evolution of the sea surface temperature. A comparative analysis of seasonally averaged anomalies of atmospheric circulation shows prospects in applying the coupled model for forecasts. It is shown with the example of the El Niño phenomenon of 1997–1998 that the coupled model forecasts the seasonally averaged anomalies for the period of the nonstationary El Niño phase significantly better. 相似文献
4.
V. V. Shashkin M. A. Tolstykh A. R. Ivanova E. N. Skriptunova 《Russian Meteorology and Hydrology》2017,42(9):554-563
The SL-AV atmospheric model version using hybrid vertical coordinates combies the advantages of sigma and isobaric coordinates. The formulation and discretization of model equations maintain the equivalency of the new model version to the basic sigma version in the special case, when hybrid coordinates coincide with sigma coordinates. The SL-AV model version with hybrid vertical coordinate is verified with medium-range weather forecasts. The decrease in the errors of predicted geopotential height and wind as compared to the sigma model version is demonstrated. The use of hybrid coordinates also leads to a certain increase in forecast skill scores for some meteorological parameters characterizing aviation significant weather. 相似文献
5.
M. M. Pevzner M. L. Tolstykh A. D. Babansky 《Journal of Volcanology and Seismology》2018,12(4):242-251
It is shown that Shiveluch, which consists of several volcanic edifices that stand in one area and in part overlie each other, is a long-lived volcanic massif with a complex structure. The available data on the morphology of the edifice, age, rock compositions, primary melts, and types of eruptive activity were used to identify structurally-temporal units (STUs) in the Shiveluch volcanic massif. It was found that the generation of different-age STUs was due to the activity of at least four magma chambers with different parameters. The durations of the individual chambers were determined. The activities of these chambers were initiated and came to an end nearly instantaneously because of major collapse episodes in the edifice of the massif due to high-magnitude earthquakes. 相似文献
6.
Pevzner M. M. Lebedev V. A. Kuscheva Yu. V. Volynets A. O. Tolstykh M. L. Babansky A. D. 《Doklady Earth Sciences》2020,490(1):1-3
Doklady Earth Sciences - A first set of K–Ar isotopic ages obtained, which allowed to estimate the age of the largest volcanoes of the Anaunsky Dol (3.2, 2.2 and 1.9 Ma) and eruptive centers... 相似文献
7.
Data set of rocks and glasses whose compositions correspond to the term “adakite” (SiO2 > 56 wt %, Sr > 400 ppm, Sr/Y > 18) was compiled from two large geochemical data bases. It was revealed that the adakitic melts are characterized by extremely low abundance as compared to adakitic rocks. Only 50 adakitic compositions (~0.5%) were identified in the data base that includes the major and trace element compositions of over 9700 quenched and melt inclusion glasses. It was established that only 22 of selected analyses characterize melt inclusion glasses, while other analyses represent residual glass or “pocket melts” in ultramafic mantle xenoliths. The question of a genetic relationship between adakitic rocks, adakitic melts, and melting of subsiding plate remains open. Original data on the Shiveluch volcanic center (Kamchatka) were used to demonstrate the formation of adakitic signatures through mineral accumulation. 相似文献
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Results of numerical experiments on the simulation of a flow moving around an isolated mountain are presented. The influence
of the sizes of a barrier and of the flow velocity on characteristics of wave oscillations is discussed. All calculations
are carried out with the authors’ two-dimensional (in the vertical plane) version of a nonhydrostatic dynamic scheme, in which
equations of the dry quasi-incompressible atmosphere are solved with a semi-implicit semi-Lagrangian method. This method uses
large time steps as compared to explicit-implicit Eurlerian methods. The results of calculations agree with results obtained
by other authors, which gives hope for finding physically correct solutions in the simulation of nonhydrostatic processes
in the atmosphere. 相似文献