Osmium-187 enrichment in some plumes: evidence for core-mantle interaction?
Science
; 269(5225): 819-22, 1995 Aug 11.
Article
em En
| MEDLINE
| ID: mdl-17778741
ABSTRACT
Calculations with data for asteroidal cores indicate that Earth's outer core may have a rhenium/osmium ratio at least 20 percent greater than that of the chondritic upper mantle, potentially leading to an outer core with an osmium-187/osmium-188 ratio at least 8 percent greater than that of chondrites. Because of the much greater abundance of osmium in the outer core relative to the mantle, even a small addition of metal to a plume ascending from the D" layer would transfer the enriched isotopic signature to the mixture. Sources of certain plume-derived systems seem to have osmium-187/osmium-l88 ratios 5 to 20 percent greater than that for chondrites, consistent with the ascent of a plume from the core-mantle boundary.
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MEDLINE
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En
Ano de publicação:
1995
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Article