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Browsing ELibrary by Title
Now showing items 8630-8649 of 21934
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(2001)Oxidation of pyrite (FeS2) under anaerobic conditions in marine sediments is experimentally shown for the first time. In slurry experiments with 55FeS2 and a MnO2 rich marine sediment an oxidation of 55FeS2 was detected ...
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(1988)The characteristic hypogene mineralization in silver deposits is represented by silver sulfosalts (pyrargyrite, freibergite, polybasite, stephanite, or stromeyerite) in addition to galena, sphalerite, chalcopyrite and ...
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(2001)High-resolution Fe K-edge XANES spectra of a series of crystalline Fe2+- and Fe3+-bearing model compounds were measured in an effort to correlate characteristics of the pre-edge feature with oxidation state and local ...
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(2001)The acid and base dissociation constants of FeO and Fe2O3 components in silicate melts are defined in terms of observed relationships between atomistic properties of dissolved oxides (nephelauxetic parameters, electronegativity, ...
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(1986)Precise new analyses of ferrous and total iron for 78 hand-picked mid-ocean ridge basalt (MORB) glasses constrain the redox states of MORB magmas, and the systematics of those redox states with respect to geography and ...
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(2000)The crystal chemistry of Fe in four nontronites (Garfield, Panamint Valley, SWa-1, and NG-1) was investigated by chemical analysis, X-ray goniometry, X-ray absorption pre-edge spectroscopy, powder and polarized extended ...
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(2000)The crystallochemical structure of reduced Garfield nontronite was studied by X-ray absorption pre-edge and infrared (IR) spectroscopy, powder X-ray diffraction, polarized extended X-ray ab-sorption fine structure (P-EXAFS) ...
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(1986)Published analyses of Fe2O3 and FeO in basaltic glassy lavas allow their equilibrium oxygen fugacities to be calculated. These values are plotted relative to NNO (nickel-nickel oxide oxygen buffer) at the same temperature ...
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(2000)Pd-Sb-Bi oxides occur in the exocontact sulphide ores of the Chiney anorthosite-gabbronorite massif. Three types of oxides have been distinguished: Pb-Sb, Pd-Sb-Bi, and Pd-Bi oxides. Pd-Sb oxides are complete pseudomorphs ...
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(2001)Mineral, chemical, and isotopic (C, O) compositions were studied in carbonatite-like rocks from 11 areas in the Nizhnyaya and the Podkamennaya Tunguska drainage basins. Based on the internal structures and mineral compositions ...
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(2003)For five tektite glasses (moldavites, indochinites, and irgizite), oxygen fugacity (fO2) was measured within the temperature range of 800-1150°C using solid electrochemical cells, and water content was analyzed with FTIR ...
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OXYGEN AND HYDROGEN ISOTOPE COMPOSITIONS IN CLAY MINERALS: A POTENTIAL SINGLE-MINERAL GEOTHERMOMETER (1996)The opposite slopes of the isotopic fractionation of hydrogen and oxygen in the clay-water system and the well-known relationship between δD and δ18O in meteoric waters allow the isotopic composition of clay minerals to ...
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(2000)Hydration complexes of the ions Li+, Na+, Mg2+, F-, Cl-, and Br- that are expected to occur in natural brines, hydrothermal solutions, or volcanic vapors were studied theoretically using quantum mechanical methods, in ...
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(1999)The oxygen and hydrogen isotope compositions of minerals and whole rock were determined for two types of gneiss (biotite gneiss and granitic gneiss) associated with ultrahigh pressure (UHP) eclogites in the Shuanghe district ...
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(2001)Bacterial disproportionation of elemental sulfur is an important process in the sulfur cycle of natural sediments and leads to the formation of hydrogen sulfide and sulfate. The oxygen atoms in sulfate during this anaerobic ...
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(2003)Considered is the problem of diffusion viscosity η determination for minerals (or rocks) with ideal crystalline structure. The calculation is conducted according to the formula: η=(0.05T/D)exp(E/RT), where T - temperature, ...
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(1997)Oxygen diffusion in natural, non-metamict zircon was characterized under both dry and water-present conditions at temperatures ranging from 765°C to 1500°C. Dry experiments were performed at atmospheric pressure by ...
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(1999)The oxidation states of Ni, Co, Mn, Cr, V and Si in magnesiowüstite have been determined in metal-oxide distribution experiments using a multi anvil apparatus at 9 and 18 GPa and 2200°C as a function of oxygen fugacity. ...
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(1996)The oxygen isotopic composition of phosphate (δ18Op) and structural carbonate (δ18Oc) of hydroxylapatite was determined in 31 bone and tooth samples of modern mammals from different countries. These two variables are highly ...
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(1997)The δ18O values of fine-grained materials made with the laser-extraction technique are often lower than those obtained conventionally. We propose a simple method to overcome this problem that involves the mixing of samples ...
Now showing items 8630-8649 of 21934