Experimental modeling of the interaction of subducted carbonates and sulfur with mantle silicates

摘要

Experimental studies in the system Fe,Ni-olivine-carbonate-S (P = 6.3 GPa, T = 1050-1550A degrees C, t = 40-60 h) aimed at modeling of the interaction of subducted carbonates and sulfur with rocks of the silicate mantle and at investigation of the likely mechanism of the formation of mantle sulfides were performed. It is shown that an association of olivine + orthopyroxene + magnesite + pyrite coexisting with a sulfur melt/fluid with dissolved Fe, Ni, and O is formed at T aecurrency sign 1250A degrees C. An association of low-Fe olivine, orthopyroxene, and magnesite and two immiscible melts of the carbonate and S-Fe-Ni-O compositions are formed at T aeyen 1350A degrees C. It is shown that the reduced S-bearing fluids may transform silicates and carbonates, extract metals from the solid-phase matrix, and provide conditions for generation of sulfide melts.