Porphyry Copper and Epithermal Gold–Silver Mineralization of the Baimka Ore Zone, Western Chukotka, Russia

The results of modern studies of the Baimka Ore Zone (BOZ) in Western Chukotka obtained during prospecting and exploration in 2008–2016 are summarized, and the main features of its structure and development are shown. The porphyry–epithermal ore systems of the BOZ were formed within the NW-trending regional-scale dextral strike-slip fault in the Early Cretaceous time. Meridional extensional structures and diagonal strike-slip faults in the strike-strip fault zone controlled the position and morphology of intrusive bodies of monzonites and paragenetically related with them ore stockworks with porphyry copper and gold–silver epithermal mineralization. Ore stockworks were traced to 700-m depth by drilling, and, accordingly to the geophysical data, mineralization is forecasting deeper. The zoning of soil anomalies and the primary geochemical zoning of the Peschanka deposit and the Nakhodka ore field are described. An erosion levels of deposits are different. For the Peschanka deposit, an upper-middle erosion level has been established. For the deposits of the Nakhodka Ore Field, the erosion grade changes from the upper to the lower level. New prospects have been identified within the BOZ, where economical porphyry copper and gold–silver epithermal mineralization is predicted.