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Browsing ELibrary by Title
Now showing items 8686-8705 of 21936
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(1995)A simple and precise method of determining the oxygen isotopic composition of Ag3PO4 has been developed in which orthophosphate is condensed to pyrophosphate and higher polymeric forms at elevated temperatures using Br2 ...
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(2000)We have located small areas of siderite within the mesostasis of the Nakhla meteorite. High concentrations of Mn (up to ∼50% rhodochrosite) and elevated D/H ratios indicate that the siderite is not a terrestrial alteration ...
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OXYGEN ISOTOPIC COMPOSITION OF OPALINE PHYTOLITHS: POTENTIAL FOR TERRESTRIAL CLIMATIC RECONSTRUCTION (1996)Opaline mineralized bodies are produced by many terrestrial plants and accumulate in certain soils and archaeological sites. Analyses of the oxygen isotopic compositions of these so-called phytoliths from stems and leaves ...
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(2004)Oxygen isotopic compositions of silicate inclusions in IVA iron meteorites have been measured with an in situ UV laser microprobe technique. The homogeneity of oxygen isotopic compositions within and among individual mineral ...
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(2003)The oxygen isotopic distribution in an amoeboid olivine aggregate (AOA), TTA1-02, from the Allende CV3 chondrite has been determined by secondary ion mass spectrometry. The irregular shaped TTA1- 02 (5×3mm) consists mostly ...
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(2004)Amoeboid olivine aggregates (AOAs) from the reduced CV chondrites Efremovka, Vigarano, and Leoville consist of forsteritic olivine, FeNi-metal and a refractory component composed of spinel, Aldiopside, anorthite. Secondary ...
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(1992)The two oxygen isotope ratios18O/16O and17O/16O were analyzed in Precambrian (3.5 Gy) and modern cherts and in mantle-derived lavas. All samples exhibit oxygen isotopic compositions consistent with mass-dependent isotopic ...
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(2006)We report oxygen isotopic compositions for 14 zircon grains from a sample of sawdust from lunar breccia 14321. The zircons range in age from ?4.4 to 3.9 Ga and in U and Th content from a few to several hundred ppm. As such ...
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(2004)The oxygen isotopic micro-distributions within and among minerals in a coarse-grained Ca, Al-rich inclusion (CAI), 7R-19-1 from the Allende meteorite, were measured by in situ using secondary ion mass spectrometry (SIMS). ...
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(1998)17O solid state nuclear magnetic resonance (NMR) was applied to study the oxygen exchange kinetics between framework oxygens and oxygens in the channel waters in the zeolite mineral stilbite. We have shown that framework ...
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(1998)17O solid state nuclear magnetic resonance (NMR) was applied to study the oxygen exchange kinetics between framework oxygens and oxygens in the channel waters in the zeolite mineral stilbite. We have shown that framework ...
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(2002)We describe here high-field 17O magic-angle-spinning (MAS) and triple-quantum MAS (3QMAS) NMR spectra for several alkali silicate and Na, K, and Ca aluminosilicate glasses containing up to 10 wt.% water. The H2O site appears ...
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(2001)Nuclear Magnetic Resonance (NMR) studies of 17O in silicate glasses is beginning to provide new information on structure from an ''anionic'' viewpoint, which is an important complement to more traditional discussions of ...
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(2003)Diamond-bearing carbonate rocks from Kumdy-Kol, Kokchetav massif, Kazakhstan, were strongly altered by fluids flowing through fractures and infiltrating along grain boundaries during exhumation. Alteration includes ...
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(1999)Substantial amounts of alcohols occur in the desulfurization products of sulfur-rich nonpolar macromolecular fractions (NPMF) isolated from two crude oils and a sediment extract. These macromolecularly bound oxygenated ...
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(2004)Using molecular dynamics simulations and electronic structure methods, we postulate a mechanism to explain the complicated reactivity trends that are observed for oxygen isotope exchange reactions between sites in aluminum ...
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(1990)In the summer (July-September) of 1989, the question of the coexistence of hydrogen sulfide and oxygen in the Black Sea was investigated in detail during a cruise of the R/V Dmitriy Mendeleyev. Reliably detectable oxygen ...
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(1987)The paper reports on a study of the so-called dark inclusions in carbonaceous chondrites in order to accumulate experimental data on meteorite components, the scale of oxygen-isotope fractionation in cosmic processes, and ...
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(2005)With one exception, the low-FeO relict olivine grains within high-FeO porphyritic chondrules in the type 3.0 Acfer 094 carbonaceous chondrite have Δ17O (= δ17O − 0.52 × δ18O) values that are substantially more negative ...
Now showing items 8686-8705 of 21936