R
Richard J. Walker
Researcher at University of Maryland, College Park
Publications - 309
Citations - 22345
Richard J. Walker is an academic researcher from University of Maryland, College Park. The author has contributed to research in topics: Mantle (geology) & Chondrite. The author has an hindex of 77, co-authored 290 publications receiving 20045 citations. Previous affiliations of Richard J. Walker include United States Geological Survey & National Institute of Standards and Technology.
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Re-Os Ages of Group IIA, IIIA, IVA, and IVB Iron Meteorites
TL;DR: In this article, negative thermal ionization mass spectrometry with modified digestion and equilibration techniques was used to determine the rhenium and osmium concentrations and ratios of group IIA, IIIA, IVA, and IVB iron meteorites.
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THE Re-Os ISOTOPE SYSTEM IN COSMOCHEMISTRY AND HIGH-TEMPERATURE GEOCHEMISTRY
TL;DR: The Re-Os isotope sytem, based on the long-lived β− transition of 187Re to 187Os, has matured to wide use in cosmochemistry and high-temperature geochemistry as discussed by the authors.
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Carius tube digestion for low-blank rhenium-osmium analysis
TL;DR: A relatively high-temperature oxidizing digestion using aqua regia has been developed for <0.1-5 g size samples of various types of rocks including silicates, sulfides, and metals prior to Re-Os isotopic analysis as discussed by the authors.
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Os, Sr, Nd, and Pb isotope systematics of southern African peridotite xenoliths: Implications for the chemical evolution of subcontinental mantle
TL;DR: Isotope analyses of Os, Sr, Nd, and Pb elements were caried out on twelve peridotite xenoliths from the Jagersfontein, Letseng-la-terae, Thaba Patsoa, Mothae, and Premier kimberlites of southern Africa, to investigate the timing and the nature of melt extraction from the continental lithosphere and its relation to the continent formation and stabilization.
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Osmium isotopic compositions of mantle xenoliths: A global perspective
TL;DR: Menzies et al. as mentioned in this paper used spinel-bearing mantle peridotites from a common fertile source (PUM) between 1 and 2 Ga ago to estimate the chemical composition of domains within the mantle.