Collaborative Research: Characterizing the Late Veneer

Carnegie Institution Of Washington, Washington DC

Investigators

Abstract

Collaborative Research: Characterizing the Late Veneer EAR-0207107; EAR-0207183 PIs: Walker and Becker; Horan The object of this study is to more precisely and accurately characterize the concentrations, in particular the relative abundances, of the highly siderophile elements (Au, Re, Os, Ir, Ru, Rh, Pt, Pd; elements with very high affinities for iron) in the bulk silicate earth. The concentrations of these elements were likely set via continued accretion of the earth (0.1 to 0.5% of planetary mass) subsequent to the segregation of the metallic core. Questions we hope to answer are: 1) what is the dominant signature of this suite of elements in the bulk silicate earth, and can this signature be tied to precursor materials that experienced particular nebular or other early solar system processes? 2) does the upper mantle of the Earth exhibit heterogeneities in the relative abundances of these elements that cannot be attributed to indigenous processes? and 3) did the composition of the late accreted material change with time? To accomplish these goals, we will analyze materials from the terrestrial mantle and melt rocks and breccias from the surface of the Moon for Os isotope compositions and highly siderophile element abundances.