Influence of Water on Sulfur Solubility in Mafic Melts at High Pressures

摘要

Sulfide-silicate liquid immiscibility (liquation) in silicate melts plays an important role in magmatic differentiation and the formation of sulfide deposits in layered mafic-ultramafic intrusions. The presence of magmatic sulfides in rocks and minerals of different depth facies indicates the existence of sulfide-silicate magmas over a wide range of upper mantle and crustal depth. To determine conditions of sulfide-silicate liquid immiscibility, it is important to know the sulfur solubility in magmas under sulfide saturation at different P-T-X conditions. Available experimental data with some exceptions characterize sulfur solubility in "dry" silicate melts under atmospheric pressure. Sulfur solubility in fluid-bearing magmatic melts has been less studied. However, volatiles, mainly H_2O and CO_2, are important factors of magmatic differentiation and the ore potential of magmas. This work presents results of an experimental study of sulfur solubility in hydrous mafic melts coexisting with harzburgite assemblage within T = 1250-1350℃ and P = 3-25 kbar.