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Now showing items 13910-13929 of 39124
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(2000)Analysis of recently reported numerous U-Pb dates from zircons from Vendian-Lower Cambrian volcanogenic rocks demonstrated that they depend on various factors, especially on postdepositional loss of radiogenic lead. ...
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(2003)Large-scale first-principles density functional theory (DFT) calculations have been carried out to investigate how Al3+ can be incorporated into MgSiO3 perovskite under high pressure and to study the resultant change in ...
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SUBSTITUTION OF ALBITE BY SANIDINE: INFLUENCE OF THE DISTANCE BETWEEN MINERALS ON THE REACTION RATE (2000)Experiments in hermetic platinum capsules were carried out on the rate of the reaction (r) of sanidine for albite substitution (Ab → San) in 0.1 m KHCO3 solution (pH = 9) at 300°C and varying distance (L) between primary ...
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(1997)Compositional trends of natural samples of scapolite extend toward the ideal (anhydrous) end-members marialite (Ma) Na4Al3Si9O24Cl and meionite (Me) Ca4Al6Si6O24CO3. Intermediate members do not follow the plagioclase ...
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(PANGAEA, 2018-03-29)Within the Russian-German research project CARBOPERM the organic matter (OM) in several permafrost cores from Bol'shoy Lyakhovsky Island in NE Siberia was investigated. In the context of the observed global warming the aim ...
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(1998)Synthetic Ca-exchanged birnessite (CaBi) was studied by X-ray and selected-area elec- tron diffraction (XRD, SAED). The substructure of CaBi may be described with a four- layer monoclinic subcell with a 5 5.150, b 5 2.844, ...
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(2001)The evolution of Earth models is reviewed and the open questions and problems are highlighted. Generally, evolution of science was not linear, but proceeded in “steps” of paradigms; where old ones remained within useful ...
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(2003)Spatial characterization of non-Gaussian attributes in earth sciences and engineering commonly requires the estimation of their conditional distribution. The indicator and probability kriging approaches of current nonparametric ...
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(PANGAEA, 1986-01-26)
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(1997)The shergottite and ALH84001 meteorites hold keys for understanding geologic and possibly biologic processes on Mars. Recently, it has been proposed that carbonates in ALH84001, and the Fe-sulfides they contain, are products ...
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(2002)While studying high-alkaline pegmatites of the Koashva deposit (Khibiny Massif) in addition to widely spread sulfides (galena, sphalerite, chalcopyrite, and cobaltite), rare potassium sulfides were identified: djerfisherite, ...
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(2003)The reaction between synthetic ferrihydrite and dissolved sulfide was studied in artificial seawater and 0.42 M NaCl at 25 °C over the pH range 4.0-8.2. Electron transfer between solid phase Fe(III) and surface-complexed ...
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(1988)The authors discuss this first attempt to determine sulfide sulfur systematically in solutions trapped as inclusions in minerals in order to study the behavior of sulfur during the formation of tin deposits of the ...
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(1996)The sulfur concentrations and the relative proportions of S2− and S6+ were measured by electron microprobe in a series of melt inclusions trapped in phenocrysts from different subduction-related and within-plate volcanoes. ...
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SULFUR AND CARBON ISOTOPES IN THE BLACK SMOKER HYDROTHERMAL VENT ECOSYSTEMS OF THE URAL PALEOOCEAN (2004)The isotopic compositions of sulfide minerals and organic carbon (Corg) from the biomorphic ore of black smokers in the South Ural paleocean were studied. The δ34S values of sulfide minerals from pseudomorphs after ...
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(2004)The solubilities of S and Cl have been determined at 850 °C, 200 MPa, and fO2 ~NNO in a rhyodacitic melt of the Unzen volcano in equilibrium with a fluid phase of mixed composition (H–O–Cl–S). The partitioning of Cl between ...
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(PANGAEA, 1987-06-21)
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(2004)One of the most promising mechanisms for the mass extinction at the K/T boundary event is blockage of sunlight by sulfuric acid aerosol, which is induced by impact vaporization of sulfate in evaporite deposits around the ...
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(PANGAEA, 1996-06-28)
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(2001)Sulfur is a major contaminant of atmospheric air resulting mainly from fuel combustion, primarily coal. This paper deals with the ecological aspects of sulfur geochemistry of coal, including the paleogeographic sulfur ...
Now showing items 13910-13929 of 39124