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Browsing ELibrary by Title
Now showing items 6885-6904 of 21934
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(2001)Digital broadband seismograms recorded from 1988 to 2000 at the stations of MDJ and HIA were used to study the mantle discontinuities and the influence of subducting slab under the Japan Sea on the 660km discontinuity ...
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(1995)The strong control that the endothermic phase change from spinel to perovskite and magnesiowustite at a depth of 660 km has on mantle convection is discussed. The phase transition determines the morphology and length scales ...
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(1989)Despite recent geochemical studies advocating an origin of eclogite xenoliths in kimberlite by subduction of altered sea-floor basalts and crustal cumulates, there are numerous examples showing abundant exsolution of garnet ...
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(1996)Laboratory models of lithosphere necking have been used to study the modes of passive margin formation and related mantle exhumation at continent-ocean boundary. Four-layer models were constructed with sand and silicone ...
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(2002)The isotopic composition of He and Ar was analyzed in rocks and minerals from the Early Protero-zoic Litza-Araguba diorite-granite complex in the northwestern part of the Kola Peninsula. The initial 4He/3He ratio of the ...
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(1996)A total dissolution technique has been developed and used to identify and quantify the incompatible element contents of fluids trapped in inclusions in minerals from peridotite xenoliths using ''fluids'' in the generic ...
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(1988)The trace element composition of basalts dredged at the axis of the Mid-Atlantic Ridge between 12°N and 17°N by the R/V “Akademik Boris Petrov” demonstrates the presence of a high-amplitude geochemical anomaly, centered ...
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(1994)Analyses of 227 rocks from fifty localities throughout the world showed that mantle derived rocks such as tectonized peridotites in ophiolite sequences (tectonites) arid peridotite xenoliths in alkali basalts contain heavier ...
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(2002)Observations of the geochemical diversity of mid-oceanic ridge and ocean-island basalts have traditionally been attributed to the existence of large-scale mantle heterogeneity. In particular, the layered convection model ...
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(1993)The apparent distinction between atmospheric and mantle²⁰Ne²²Ne ratios may provide a technique to quantify air contamination in mantle-derived materials. In the absence of mantle nuclear reactions, which produce either²⁰Ne ...
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(2001)This paper interprets the conditions of plume formation with a focus on interpretations of origin at the core-mantle boundary. We also discuss important geological manifestations including formation of alkaline-basalt ...
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(2003)The periodicity of plume magmatism has been reviewed in this paper, which also demonstrates a correlation between trap magmatism and Permo-Triassic granitoids as well as general regularities of collision and postcollision ...
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(2003)Late Cenozoic alkaline basic volcanics in the Baikal Rift Zone and adjacent territories of eastern Siberia and central Mongolia are relatively small in volume. However, the geochemical and isotopic signatures indicate that ...
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(1991)Magnetic reversal frequency correlates inversely with mantle plume activity for the past 150 Ma, as measured by the volume production rate of oceanic plateaus, seamount chains, and continental flood basalts. This inverse ...
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(2000)We have employed an axisymmetric, spherical shell model with the two major phase transitions and variable viscosity to study the dynamical processes associated with both regular mantle plumes and superplumes, which can ...
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(2005)Mantle preconditioning may be defined as the extraction of small melt fractions from mantle asthenosphere during its flow to the site of magma generation. Equations may be written for mantle preconditioning, assuming that ...
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(2001)Inferences on the rheology of the mantle based on theoretical and experimental rate equations for steady state creep are discussed and compared with results from geophysical models. The radial increase of viscosity by one ...
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(2001)The paper presents results of the investigation of the major-, trace-, and rare-earth element compositions of kimberlites from various regions of the Yakutian diamond-bearing province with application to determining mantle ...
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(2002)The origin of the Baikal rift zone (BRZ) has been debated between the advocates of passive and active rifting since the 1970s. A re-assessment of the relevant geological and geophysical data from Russian and international ...
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(2001)We examine the effects of non-uniform rheology and melting models on the 3D structure of mantle upwelling beneath spreading centers. Our numerical models identify a range of conditions for which 3D upwelling can be considered ...
Now showing items 6885-6904 of 21934