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Science 11 August 1995:
Vol. 269. no. 5225, pp. 819 - 822
DOI: 10.1126/science.269.5225.819
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Articles

Osmium-187 Enrichment in Some Plumes: Evidence for Core-Mantle Interaction?

Richard J. Walker 1, John W. Morgan 2, and Mary F. Horan 2

1 Isotope Geology Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, USA.
2 M.S. 981, U.S. Geological Survey, Reston, VA 22092, USA.

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.

Submitted on March 13, 1995
Accepted on June 6, 1995


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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CORE MANTLE CHEMICAL ISSUES.
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Large igneous province magma petrogenesis from source to surface: platinum-group element evidence from Ontong Java Plateau basalts recovered during ODP Legs 130 and 192.
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Proton microprobe results for the partitioning of platinum-group elements between monosulphide solid solution and sulphide liquid.
S.-J. Barnes, E. van Achterbergh, E. Makovicky, and C. Li (2001)
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Heavy Nitrogen in Carbonatites of the Kola Peninsula: A Possible Signature of the Deep Mantle.
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A Correlation Between Ultra-Low Basal Velocities in the Mantle and Hot Spots.
Q. Williams, J. Revenaugh, and E. Garnero (1998)
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Coupled 186Os and 187Os Evidence for Core-Mantle Interaction.
A. D. Brandon, R. J. Walker, J. W. Morgan, M. D. Norman, and H. M. Prichard (1998)
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