Mineral assemblages of the porphyry tin-polymetallic ores of Mount Krasnaya paleovolcano of the Krasnogorsky deposit in the Dal’negorsk ore district

This paper presents the results of the detailed mineralogical study of the pocket-disseminated tinzinc (cassiterite-sulfide) and vein-metasomatic tin-silver-polymetallic ores localized in the vent of the Mount Krasnaya paleovolcano (Krasnogorsky polymetallic deposit). The tin-zinc ores of the early Late Maastrichtian stage of the ore formation are associated with pipelike bodies of explosion breccias, were formed at a temperature of around 300°C, and include three mineral assemblages: the (1) pyrite, (2) productive quartz-cassiterite-sphalerite, and (3) late sulfosalt-galena-chalcopyrite ones. The vein-metasomatic tin-silver-polymetallic ores of the late Paleocene stage are associated with rhyolite bodies, controlled by the NW-oriented faults, and cut mineralized breccia. These ores were formed during a full two-stage hydrothermal cycle within the temperature interval from 500 to 1000°C and include five consecutive ore mineral assemblages: (1) wolframite-arsenopyrite, (2) cassiterite-sphalerite-pyrite-chalcopyrite, (3) stannite-Ag-bearing sulfosalt, (4) freibergite-galena, and (5) native silver-stephanite-acanthite. The tin-silver-polymetallic ores are assumed to have formed simultaneously with the extended silver-bearing galena-sphalerite veins cutting the Primorskaya Group volcanic rocks around the paleovolcano. In the extended vein zones, the tinsilver-polymetallic ores correspond to the uppermost (closest to the paleosurface) part of the vertical zoning.