in the Earth and Shergottite Parent Chemical evidence from basaltst

• Main Authors: Allan H. Treiman, Michael J. Drake, Marie-josee Janssen, _. __
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1985
• Subjects: Antarctic; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.3788; http://www.mars.asu.edu/christensen/classdocs/Treiman_CoreFormation_gca_86.pdf

Abstract-Constraints on processes of core formation in terrestrial planets may be inferred from the abun-dances of siderophile and chalcophile elements in their mantles. Of particular interest is a comparison of processes of core formation in the Earth and in the Shergottite Parent Body (SPB), a terrestrial planet tentatively inferred to be Mars. To this end, we (i) present new INAA and RNAA analyses of the non-Antarctic SNC meteorites, (ii) infer the composition of the SPB mantle from the compositions of the SNC meteorites, (iii) infer the composition of the Earth’s mantle from the compositions of terrestrial basahs, and (iv) deconvolve the effects of volatile depletion, core formation, and mineral/melt fractionation on the abundances of siderophile and chalcophile elements in the SPB and the Earth. Element abundances in the mantles of the SPB and the Earth are estimated from element/element correlations observed among basalt samples. In basalts from the SPB (the SNC meteorites), four groups of covariant elements are observed: highly incompatible, moderately incompatible, indifferent and compatible. From correlations within these groups, the SPB mantle is found to be depleted in volatile elements, and strongly depleted in siderophile and chalcophile lements. For the Earth the element/element correlation method gives a mantle composition similar to previous estimates. Compared to the Earth, the SPB mantle is richer in moderately siderophile elements (e.g., W, P), consistent with its inferred higher oxidation state. Chalcophile elements in the SPB