Coupled 186 Os and 187 Os Evidence for Core-Mantle Interaction

• DOI: 10.1126/science.280.5369.1570
• Publication Date: 2002-07-27T09:35:26Z
• Authors: Alan D. Brandon; Richard J. Walker; John W. Morgan; Marc D. Norman; Hazel M. Prichard
• Keywords: Osmium; Outer core; Mantle plume; Core–mantle boundary

Osmium isotopic analyses of picritic lavas from Hawaii show enrichments in the osmium-186/osmium-188 ratio (186Os/188Os) 0. 008 to 0.018%, relative a chondritic upper mantle, that are positively correlated with 187Os/188Os 5.4 9.0%. The most viable mechanism produce these coupled 186Os and 187Os is by addition 0.5 1 weight percent outer core metal portion D" layer subsequent upwelling mixture. These data suggest some plumes originate at core-mantle boundary Os isotopes may be used distinguish derived shallow versus deep mantle sources.