Evidence of Mineral Melting in Ores of the Svetlinsk Gold Deposit, South Urals, Russia

The evidences of partial melting of minerals and the possible involvement of polymetallic melts in the accumulation and redistribution of gold and other metals are shown for the large Svetlinsk gold deposit (Southern Urals). The finding of Bi and Sb minerals including new Au minerals for the deposit (pampaloite, montbrayite, and aurostibite), specific mineral intergrowths (polymineral Sb–Bi–Pb–Te–Ag–Au drop-like inclusions), enrichment of early sulfides in Low-Melting-Point Chalcophile Elements (LMCE), high formation temperatures of ore assemblages (up to 400°C), as well as metamorphism of amphibolite facies of the deposit indicate the possibility of formation of such melts. The polymetallic melts at the deposit could be formed both by partial melting of early sulfides and directly from hydrothermal fluids. The melting features also include calaverite–native gold symplectites in the marginal parts of a large montbrayite grain.