Precious-Metal Mineralization in Gabbroids of the Kumba Intrusive, Uralian Platinum Belt (North Urals)

Abstract

The paper presents the first data on the distribution and composition of copper–precious-metal mineralization in gabbroids of the Kumba intrusive (North Urals). The precious-metal mineralization is associated with digenite–bornite, bornite-chalcopyrite, and pyrite–chalcopyrite ores. Nine precious-metal minerals and their varieties were identified in amphibole and amphibole–olivine gabbro of the Kumba intrusive for the first time: native gold, Au–Ag alloys, Ag and Pd tellurides (hessite, merenskyite), Bi tellurides (kotulskite), antimonide–arsenides (isomertieite), arsenides (arsenopalladinite, sperrylite), and stannides (atokite) of Pt and Pd. Precious-metal minerals from all sulfide assemblages in heavy concentrates are often accompanied by antimonides (stibnite) and Bi mineralization represented mainly by native bismuth and bismuthinite and less common sulfotellurides (baksanite) and tellurides (tsumoite). Our results make it possible to estimate the prospects of the discovery of new copper–precious-metal deposits hosted in gabbro of the Uralian Platinum Belt. Taking into account the regularities of distribution of precious metal and copper mineralization, most gabbro massifs in the Uralian Platinum Belt can be considered the promising objects for searching the large-tonnage copper deposits with associated ore Au and Pd grades.