Coupled <sup>186</sup> Os and <sup>187</sup> Os Evidence for Core-Mantle Interaction

DOI Web Site 7 Citations
  • Alan D. Brandon
    A. D. Brandon, R. J. Walker, J. W. Morgan, Isotope Geochemistry Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, USA.
  • Richard J. Walker
    A. D. Brandon, R. J. Walker, J. W. Morgan, Isotope Geochemistry Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, USA.
  • John W. Morgan
    A. D. Brandon, R. J. Walker, J. W. Morgan, Isotope Geochemistry Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, USA.
  • Marc D. Norman
    A. D. Brandon, R. J. Walker, J. W. Morgan, Isotope Geochemistry Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, USA.
  • Hazel M. Prichard
    A. D. Brandon, R. J. Walker, J. W. Morgan, Isotope Geochemistry Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, USA.

Abstract

<jats:p> Osmium isotopic analyses of picritic lavas from Hawaii show enrichments in the osmium-186/osmium-188 ratio ( <jats:sup>186</jats:sup> Os/ <jats:sup>188</jats:sup> Os) of 0.008 to 0.018%, relative to a chondritic upper mantle, that are positively correlated with enrichments in <jats:sup>187</jats:sup> Os/ <jats:sup>188</jats:sup> Os of 5.4 to 9.0%. The most viable mechanism to produce these coupled <jats:sup>186</jats:sup> Os and <jats:sup>187</jats:sup> Os enrichments is by addition of 0.5 to 1 weight percent of outer core metal to a portion of the D" layer and subsequent upwelling of the mixture. These data suggest that some plumes originate at the core-mantle boundary and that Os isotopes may be used to distinguish plumes derived from shallow versus deep mantle sources. </jats:p>

Journal

  • Science

    Science 280 (5369), 1570-1573, 1998-06-05

    American Association for the Advancement of Science (AAAS)

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