Recycling Osmium

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Science  10 May 1996:
Vol. 272, Issue 5263, pp. 825
DOI: 10.1126/science.272.5263.825


In the vicinity of so-called subduction zones, one crustal plate is pushed under another, leading to recycling of elements in the crust. Noble metals such as platinum and osmium were not thought to participate in this recycling, but as Snow discusses in his Perspective, this picture needs rethinking. He comments on results reported by Brandon et al. (p. 861) in this same issue that show that osmium is in fact recycled out of subducted oceanic crust into the overlying mantle. Snow also discusses the new tools for measuring rhenium-osmium isotope ratios that made the research possible.