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Shirey, S.B. and Walker, R.J. (1998). The Re-Os isotope system in cosmochemistry and high-temperature geochemistry. Annual Review of Earth and Planetary Sciences 26: 423-500. |
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The Re-Os isotope sytem, based on the long-lived beta(-) transition of Re-187 to Os-187, has matured to wide use in cosmochemistry and high-temperature geochemistry. The siderophilic/chalcophilic behavior of Re and Os is different from that of the elements that comprise most other long-lived radiogenic isotope systems. Magmatic iron meteorites (IIIAB, IIAB, IVA, and IVB) have Re-Os isochrons that indicate asteroidal core crystallization within the first 10-40 million years of Solar System evolution. Rocks from Earth's convecting mantle show generally chondritic Re/Os evolution throughout Earth history that is explained by the addition of highly siderophile elements to the mantle after core formation via late accretion. Oceanic basalts have Os-isotope systematics that improve the detailed geological interpretation of extant mantle components. Some portions of ancient subcontinental lithospheric mantle are severely depleted in Re and have correspondingly subchondritic Os-187/Os-188, indicating long-term isolation from the convecting mantle during the Archean-Proterozoic. Magmatic ore deposits have differences in initial Os isotopic composition traceable to the crustal vs mantle sources of the platinum-group elements and base metals. |
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Keywords
chondrites, core, igneous rocks, iron meteorites, isotope ratios, lithosphere, mantle, mantle evolution, mantle plumes, mineral deposits, osmium, rhenium, platinum-group elements, changing partition-coefficients, ionization mass-spectrometry, archean lithospheric mantle, oceanic island basalts, mid-atlantic ridge, rb-sr isotope, iron-meteorites, rhenium-osmium, stillwater complex |
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