Siderophile elements metal-silicate equilibria

The geochemical models of Wanke and Dreibus (1988), Lodders and Fegley (1997), and Sanloup et al. (1999) suggest that the core comprises 20.6-23.0% of the mass of Mars. All these model cores are sulfur rich, but differ significantly in core mass and sulfur abundance (Table 5). Measured siderophile element abundances in martian meteorites are consistent with equilibrium between sulfur-bearing metal and silicate at high temperature and pressure (Righter and Drake, 1996). 

Estimates of the Mars core composition by the authors listed above suggest it is made of metal plus iron sulfide, the latter varying from 29 to 44 wt.%. Abundances of siderophile (tungsten, phosphorus, cobalt, molybdenum, nickel) and chalcophile (indium, copper) elements in the mantle (Fig. 13.23) are consistent with equilibrium between sulfide, metal, and mantle silicate at high temperature and pressure (Righter and Drake, 1996). 

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