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

摘要: Abstract The solubility of Au in sulfur-free vs. sulfide-saturated melts and its partitioning behavior between sulfide liquid (SL), monosulfide solid solution (MSS) hydrous basanite melt at variable activities was investigated a fO2 range FMQ−2 to FMQ+1.6 1200 °C/1.5 GPa using piston cylinder apparatus. Gold ( D SL / SM ) are very high, ∼10,000 ± 3000, which is the upper end values reported previous studies. partition coefficients MSS silicate much lower, 60 ± 10, lower values. Both independent fO2. new were used conjunction with previously published Cu Ag investigate role versus during partial melting source region primitive potassic magmas crust–mantle differentiation. high content ore deposits associated has commonly been explained by dissolution Au-rich liquid, either mantle or re-melting sulfide-bearing cumulates boundary. We argue that dominant phase these magmas, thus their consequence low MSS–silicate rather than exhaustion cumulates. Continental crust depleted Au, relative melts, thought be due removal However, based on relations high-pressure high-temperature corresponding sulfide–silicate we come conclusion sulfides precipitated boundary dominated have capability sequester Pb case liquid.