Gold solubility and partitioning between sulfide liquid, monosulfide solid solution and hydrous mantle melts: Implications for the formation of Au-rich magmas and crust-mantle differentiation

Continental crust is depleted in Au, Ag and Cu relative to mantle melts, which was thought to be due to removal of sulfide liquid at the crust-mantle boundary. However, based on sulfide phase relations at high-pressure and high-temperature and corresponding sulfide-silicate melt partition coefficients we come to the conclusion that sulfides precipitated at the crust-mantle boundary are dominated by MSS rather than sulfide liquid, and thus have a much lower capability to sequester Au, Ag and Pb than in the case of sulfide liquid.