БЛАГОРОДНЫЕ И РЕДКИЕ МЕТАЛЛЫ В БОРНИТОВЫХ РУДАХ КОЛЧЕДАННЫХ МЕСТОРОЖДЕНИЙ УРАЛА

Abstract

Investigation of mineralogy and geochemistry of bornite ores was carried out for Gayskoye, Molodezhnoye, Aleksandrinskoye, Karabashskoye and the IIIrd International deposits where massive sulfide ores arc enriched in gold, silver germanium, gallium and tin. Genesis of bornite-bearing ores is related to metamorphism process, its temperatures and the sulfur fugacity values have been determined with help of electrum-sphalerite geothermo-meter. Minimum values of these parameters were estimated by the ratio of abundant S2 to CU2S in composition of digenite. During the fahlore (formerly, gray copper ore) subfacies of metamorphism the bornite mineralization took place at 270-360°C and sulfur fugacity 10-8-10-13 atm. There have been found as the high-copper sulfi-des: chalcocite Cu2S, digenite Cu1.8S, anilite Cu1.75S, so the low-copper sulfides: spioncopite Cu1.4S, yarrowite Cu1.12S and covellite CuS. Chalcocite, digenite and, possibly, anilite have the hypogene genesis, the low-copper sulfides have been generatied in oxidation conditions. There arc characterized, in the paper, compositions of bornite, fahlore, native gold, copper and silver sulfides: stromeyerite, jalpaite, mackinstryte, so as germanium- and tin-bearing sulfides: stannoidite Cu+8 Fe23+ (Fe2+, Zn 2+ )Sn24+ S12, mawsonite Cu6Fe2SnS8, germanite Cu20(Ge,V, As)4 and renierite Cu20(Zn2-x, Cux)(Ge4-x , Asx) Fe8S32.