Elemental Partitioning Constraints on the Mineralogy of the Martian Mantle

Incompatible elements weakly partition into mantle mineral phases so precise measurements of incompatible element abundances in mantle melts have been used to infer mineralogy of mantle sources [1, 2]. In a recent study [3], we showed that several incompatible chalcophile elements (As, Tl, Pb) relative to REE were more compatible in martian igneous rocks than in terrestrial basalts. This observation can be accounted for by (1) the bulk partition coefficients of chalcophile elements being higher due to the presence of more residual sulfide in the martian mantle [3] and/or (2) different relative compatibilities in the martian mantle due to differences in mineralogy. In this study, the compatibility sequences of lithophile elements in martian and MORB mantles are revised to better represent relative partitioning behavior during mantle differentiation and the influence of mantle mineralogy is examined.