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. 2002 Apr 19;296(5567):516-8.
doi: 10.1126/science.1069119.

Evidence for an ancient osmium isotopic reservoir in Earth

Anders Meibom  1 , Robert Frei
Affiliations

Evidence for an ancient osmium isotopic reservoir in Earth

Anders Meibom et al. Science. .

Abstract

Iridosmine grains from placer deposits associated with peridotite-bearing ophiolites in the Klamath mountains have extremely radiogenic 186Os/188Os ratios and old Re-Os minimum ages, from 256 to 2644 million years. This indicates the existence of an ancient platinum group element reservoir with a supra-chondritic Pt/Os ratio. Such a ratio may be produced in the outer core as a result of inner core crystallization that fractionates Os from Pt. However, if the iridosmine Os isotopic compositions are a signature of the outer core, then the inner core must have formed very early, within several hundred million years after the accretion of Earth.

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Comment in

  • Geology. Osmium remembers.
    Carlson RW. Carlson RW. Science. 2002 Apr 19;296(5567):475-7. doi: 10.1126/science.1070515. Science. 2002. PMID: 11964463 No abstract available.

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