LAUSR

The composition and genesis of Pb–As–Sb sulfosalts from ores of the Berezitovoe gold deposit, Upper Amur Region, located in the eastern part of the Mongolia-Okhotsk orogenic belt are reported. Lead (Pb–Cu) sulfosalts are tsugaruite, dufrenoysite, boulangerite, menegenite, Bi-rich menegenite (Bi up to 11.5 wt %), and minerals of the jordanite-geocronite and bournonite-seligmannite solid solution series. Basic features of the relationship between Pb sulfosalts and ore and silicate minerals in various assemblages of veinlet mineralization and variations in the chemical composition of sulfosalts have been revealed. Compositionally complex Pb (Pb–Cu)–As–Sb sulfosalts form quasi-continuous solid solution series, which differ in the proportions of semimetals, and semimetals and lead. It is suggested that the major compositional features of Pb–As–Sb sulfosalts at the Berezitovoe deposit are controlled by partial melting of sulfide minerals during high-temperature metamorphism of primary polymetallic ore.