Composition and genesis of arsenium-antimony sulfosalts of lead from the gold-bearing ores of the Berezitovoe deposit located in the eastern part of Mongol-Okhotsk orogenic belt (Upper Amur Area) were considered. Lead sulfosalts (Cu and Pb) are presented by tsugaruite, dufrenoysite, boulangerite, menegenite, bismuthic menegenite (with Bi up to 11.5 mass%), as well as minerals of jordanite-geocronite and bournonite-seligmannite series. The studies have revealed basic features of the lead sulfosalts relationship with ore and silicate minerals in different mineral association of vain ores and regularities in their composition variations. It was found that the composite arsenium-antimony sulfosalts form quasicontinuous series of solid compounds strongly differing from each other by the rate of semimetals as well as semimetals-Pb ratio in their composition.
The suggestion has been made that the main typomorphic features of composition of the arsenium-antimony sulfosalts of lead from ores of the Berezitovoe deposit were determined by the specific processes of partial melting of sulfides under the high temperature metamorphism of primary polymetallic ores.
Key words: minerals, lead sulfosalts, mineral system, homologous series, sulfide melt, ore metamorphism, gold mineralization, Berezitovoe deposit, Mongol-Okhotsk orogenic belt, Upper Amur Area.