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91.
A. N. Kruk A. G. Sokol D. A. Chebotarev Yu. A. Palyanov N. V. Sobolev 《Doklady Earth Sciences》2016,467(1):303-307
Generation of ultra-alkaline melts by the interaction of lherzolite with cardonatites of various genesis was simulated at the P–T parameters typical of the base of the subcratonic lithosphere. Experiments with a duration of 150 h were performed at 5.5 and 6.3 GPa and 1350°C. The concentrations of CaO and MgO in melts are buffered by the phases of peridotite, and the concentrations of alkalis and FeO depend on the composition of the starting carbonatite. Melts are characterized by a low (<7 wt %) concentration of SiO2 and Ca# from 0.40 to 0.47. It is demonstrated that only high-Mg groups of carbonatitic inclusions in fibrous diamonds have a composition close to that of carbonatitic melts in equilibrium with lherzolite. Most likely, the formation of kimberlite-like melts relatively enriched in SiO2 requires an additional source of heat from mantle plumes and probably H2O fluid. 相似文献
92.
Yu. V. Bataleva Yu. N. Palyanov Yu. M. Borzdov N. V. Sobolev 《Doklady Earth Sciences》2016,471(1):1144-1148
Experimental research in the Fe3C–(Fe,Ni)S system was carried out. The objective of the investigation was to model the reactions of carbide–sulfide interaction related to graphite (diamond) formation in reduced lithosphere mantle domains. T ≤ 1200°C is the formation temperature of the Ni-cohenite + graphite assemblage coexisting with two immiscible melts such as sulfide (Fe60–Ni3–S37)L and metal–sulfide (Fe71–Ni7–S21–C1)L containing dissolved carbon. Т ≥ 1300°C is the generation temperature of a unified melt such as (Fe80–Ni6–S10–C4)L characterized by graphite crystallization and diamond growth. The extraction of carbide carbon during the interaction with the sulfide melt can be considered as one of the potential mechanisms of graphite and diamond formation in the reduced mantle. 相似文献
93.
A. A. Tomilenko T. A. Bul’bak L. N. Pokhilenko D. V. Kuzmin N. V. Sobolev 《Doklady Earth Sciences》2016,469(1):690-694
The composition of volatile components in picroilmenites from Yakutian kimberlitic pipes of various ages (the Olivinovaya, Malokuonapskaya, and Udachnaya–East pipes) was studied for the first time by means of gas chromatography–mass spectrometry (GC-MS). It was shown that picroilmenites and olivines from same kimberlitic pipes contained volatile components of close composition, whereas these components were quite different in these minerals from different pipes. These features point to a common source and represent the specificity of the magma chamber formed under the pronounced influence of hydrocarbons with their derivates, as well as nitrogen-, chlorine-, and sulfur-containing compounds. The fraction of hydrocarbons and derivates in the composition of volatile matter is as high as 99%, including 9.7% of chlorine- and fluorinecontaining compounds. 相似文献
94.
This paper describes an effort to develop a predictive tool for the design of a new promising marine transport — the WIG craft. The presented mathematical model of the WIG craft is capable of modeling the aerodynamics of a WIG system including the ground effect, the hydrodynamics of a stepped planing hull with a hydrofoil and also the simulation of motion for the craft. Based on extensive experience using the model, it is shown that the most important and necessary features of WIG aero- and hydrodynamics are taken into account. The results of simulations have been validated through comparison with other theoretical approaches and also with model experiments. The mathematical model is applied to investigate the dynamics of the small manually piloted WIG craft: “Hydrowing VT01”. The numerical study resulted in recommendations allowing the pilot to overcome the pitch-up tendency and also to perform the take-off manoeuvre smoothly. The stability of the WIG with a hydrofoil and also the dynamic properties of anti-collision manoeuvres have been studied and are presented. 相似文献
95.
Oksana A. Tarasova Sander Houweling Nikolai Elansky Carl A. M. Brenninkmeijer 《Journal of Atmospheric Chemistry》2009,63(1):49-71
Presented is a detailed comparison of CH4 and δ13C–CH4 measurements with simulations of the global transport model TM3. Experimental data were obtained during campaigns along the
Trans-Siberian railroad in the framework of the TROICA project. Two summer (1999 and 2001) and one spring (2003) expeditions
are evaluated. Model simulations include sensitivity tests to further investigate the isotopic composition of natural gas
and emissions from Siberian wetlands. Comparison of the average mixing ratio of methane and its isotopic composition (δ13C) has been performed for different geographic zones, including the European part of Russia, Western Siberia and Central Siberia.
Simulations are in reasonable agreement with the measurements for the European part of Russia and confirm a high contribution
of natural gas to the observed methane levels. An increase of emission from bogs shifts the simulated methane isotopic composition
closer to the observations. The relative importance of the Western Siberia emissions in current inventories is underestimated
in comparison with other wetland regions in the former USSR. Simulated average mixing ratios are in a good agreement with
the observations in Central Siberia, while 13C(CH4) values tend to be higher than measured in all considered scenarios. These results point to a bias in the modeled source
mixture over Russia, which could be repaired by shifting emissions from isotopically heavy methane sources (e.g. coal, oil
or biomass burning) to light sources (e.g. wetlands, ruminants, waste treatment). Alternatively, the average isotopic signature
of Siberian wetlands may be lighter than expected. 相似文献
96.
Brune Sascha Ladage Stefan Babeyko Andrey Y. Müller Christian Kopp Heidrun Sobolev Stephan V. 《Natural Hazards》2010,54(2):547-562
Our analysis of new bathymetric data reveals six submarine landslides at the eastern Sunda margin between central Java and
Sumba Island, Indonesia. Their volumes range between 1 km3 in the Java fore-arc basin up to 20 km3 at the trench off Sumba
and Sumbawa. We estimate the potential hazard of each event by modeling the corresponding tsunami and its run-up on nearby
coasts. Four slides are situated remarkably close to the epicenter of the 1977 tsunamigenic Sumba M
w
= 8.3 earthquake. However, comparison of documented tsunami run-up heights and arrival times with our modeling results neither
allows us to confirm nor can we falsify the hypothesis that the earthquake triggered these submarine landslides. 相似文献
97.
Andrey A. Gurenko Kaj A. Hoernle Alexander V. Sobolev Folkmar Hauff Hans-Ulrich Schmincke 《Contributions to Mineralogy and Petrology》2010,159(5):689-702
The Canary Island primitive basaltic magmas are thought to be derived from an HIMU-type upwelling mantle containing isotopically
depleted (NMORB)-type component having interacted with an enriched (EM)-type component, the origin of which is still a subject
of debate. We studied the relationships between Ni, Mn and Ca concentrations in olivine phenocrysts (85.6–90.0 mol.% Fo, 1,722–3,915 ppm
Ni, 1,085–1,552 ppm Mn, 1,222–3,002 ppm Ca) from the most primitive subaerial and ODP Leg 157 high-silica (picritic to olivine
basaltic) lavas with their bulk rock Sr–Nd–Pb isotope compositions (87Sr/86Sr = 0.70315–0.70331, 143Nd/144Nd = 0.51288–0.51292, 206Pb/204Pb = 19.55–19.93, 207Pb/204Pb = 15.60–15.63, 208Pb/204Pb = 39.31–39.69). Our data point toward the presence of both a peridotitic and a pyroxenitic component in the magma source.
Using the model (Sobolev et al. in: Science 316:412–417, 2007) in which the reaction of Si-rich melts originated during partial
melting of eclogite (a high pressure product of subducted oceanic crust) with ambient peridotitic mantle forms olivine-free
reaction pyroxenite, we obtain an end member composition for peridotite with 87Sr/86Sr = 0.70337, 143Nd/144Nd = 0.51291, 206Pb/204Pb = 19.36, 207Pb/204Pb = 15.61 and 208Pb/204Pb = 39.07 (EM-type end member), and pyroxenite with 87Sr/86Sr = 0.70309, 143Nd/144Nd = 0.51289, 206Pb/204Pb = 20.03, 207Pb/204Pb = 15.62 and 208Pb/204Pb = 39.84 (HIMU-type end member). Mixing of melts from these end members in proportions ranging from 70% peridotite and 30%
pyroxenite to 28% peridotite and 72% pyroxenite derived melt fractions can generate the compositions of the most primitive
Gran Canaria shield stage lavas. Combining our results with those from the low-silica rocks from the western Canary Islands
(Gurenko et al. EPSL 277:514–524, 2009), at least four distinct components are required. We propose that they are (1) HIMU-type
pyroxenitic component (representing recycled ocean crust of intermediate age) from the plume center, (2) HIMU-type peridotitic
component (ancient recycled ocean crust stirred into the ambient mantle) from the plume margin, (3) depleted, MORB-type pyroxenitic
component (young recycled oceanic crust) in the upper mantle entrained by the plume, and (4) EM-type peridotitic component
from the asthenosphere or lithosphere above the plume center. 相似文献
98.
Trace elements in garnets and chromites: Diamond formation in the Siberian lithosphere 总被引:1,自引:0,他引:1
W.L. Griffin N.V. Sobolev C.G. Ryan N.P. Pokhilenko T.T. Win E.S. Yefimova 《Lithos》1993,29(3-4):235-256
Proton-microprobe analyses of trace elements in garnet and chromite inclusions in diamonds (DI) from the Mir, Udachnaya, Aikhal and Sytykanskaya kimberlites in Yakutia, CIS, provide new insights into the processes that form diamond. Equivalent data on garnet and chromite concentrates from these pipes yield information on the thermal state and chemical stratification of the Siberian lithosphere. Peridotite-suite diamonds from Yakutia have formed over a temperature interval of ca. 600°C, as measured by Ni and Zn thermometry on garnet and chromite inclusions in diamonds. Individual diamonds contain inclusions recording temperature intervals of >400°C; ranges of >100°C are common. Diamond formation followed a severe depletion event(s), and a separate enrichment in Sr. Comparison of temperatures on DI garnet and spinel with temperatures derived from diamondiferous harzburgites, exposed inclusions in boart and concentrate minerals suggests that the diamond-containing part of the lithosphere has cooled significantly since the Siberian diamonds crystallized. The peridotite-suite diamonds probably formed mainly in response to one or more relatively short-lived thermal events, related to magmatic intrusion. The northern part of the Daldyn-Alakit district may have had a typical cratonic geotherm at the time of diamond formation, and during kimberlite intrusion. The southern part of the district, and the Malo-Botuobiya kimberlite field, probably had a relatively low geotherm (ca. 35 mW/m2). The vertical distribution of garnet and chromite types indicates that the mantle above 120 km depth is dominated by lherzolites, whereas the deeper parts of the lithosphere are a mixture of lherzolites and more depleted harzburgites and dunites. 相似文献
99.
100.