Minerals of the Au-Ag-Pb-Te-Se-S system of porphyry-copper-molybdenum deposits from the Nakhodka ore field, Chukchi Peninsula, Russia

Abstract

The Nakhodka ore field located 220 km south of the Bilibino town, Chukchi Peninsula, Russia comprises Cu-Mo-porphyry (Malysh and Vesennii) and Mo-Cu-porphyry (Nakhodka, III Vesennii) deposits. The late epithermal mineralization with native gold of low fineness (498–766) of the first group deposits refers to the IS (intermediate sulfidation) type, which is characterized by the occurrence of petzite; stutzite; acanthite; pearceite; and minerals of the Pb-Bi-Ag-Se-Te, Ag-Te-Se, and Ag-Bi-Se systems, as well as by native tellurium. The epithermal mineralization forms at fTe2(−19...−18) and fS2(−14...−13) and temperatures <200°C. The second group deposits do not exhibit epithermal mineralization; telluride mineralization is present as only native tellurium and altaite.