Browsing by Title
- DSpace Home
- →
- Browsing by Title
JavaScript is disabled for your browser. Some features of this site may not work without it.
Browsing by Title
Now showing items 10613-10632 of 39003
-
(1997)Microbial activity has been invoked to explain anomalous oxygen isotope compositions of phosphate mineral deposits as well as fossil biogenic apatite. Results of laboratory experiments on enzyme-mediated reactions of ...
-
(1997)Oxygen isotope ratios are reported for olivine phenocrysts from sixty-seven samples of ocean island basalts (OlBs), mid-ocean ridge basalts (MORBs), and related peridotites, including representatives of the various isotopic ...
-
(2001)This chapter summarizes the oxygen isotope geochemistry of terrestrial basalts and their mantle sources, including the conceptual framework for interpreting such data and the phenomenology of known variations. In particular, ...
-
(1989)The authors describe the fractionation of oxygen isotopes during the generation of horizontal and vertical metasomatic zoning in the typical greisen-rare metal Akchatau deposit in Central Kazakhstan. The oxygen isotope ...
-
(2000)Calcium-aluminum-rich inclusions (CAIs) from enstatite chondrites have large 16O excesses, similar to CAIs in carbonaceous and ordinary chondrites, and are also similar in morphology, mineralogy and Al-Mg isotopic systematics. ...
-
(2000)Ion-microprobe studies yield Δ17O (=δ17O - 0.52 . δ18O) values in magnetite from the Rumurti chondrite (RC) PCA91241 (which is paired with PCA91002) of +3.1 to +3.9%%, slightly higher than that in O from whole-rock R ...
-
(2003)Isotopic and trace element analysis of zircons can provide reliable and robust estimates of age, compositions of coexisting minerals and melts, and constraints on the genesis and protoliths of host rocks. Recent technological ...
-
(2001)In order to develop the potential tool of diatom oxygen isotopes for paleoenvironmental studies we compared oxygen isotopes of natural marine diatoms sampled from ocean surface water, sediment traps and surface sediments ...
-
(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 ...
-
(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 ...
-
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 ...
-
(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 ...
-
(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 ...
-
(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 ...
-
(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 ...
-
(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). ...
-
(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 ...
-
(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 ...
Now showing items 10613-10632 of 39003