Abstract:
This paper is devoted to large commercial disseminated gold-sulfide deposits in the Russian Northeast. Their location is controlled by intrusive dome structures and tectonic blocks in zones of tectonomagmatic activation. It is demostrated that the combination of various mineral and structural types of ore mineralization results in the formation of large and unique deposits. The following types of ore deposits are distinguished, according to different ore settings and the overprinting of various mineralizations in ore bodies: (1) gold-sulfide, proper, (2) gold-sulfide-quartz, (3) gold-stibnite, and (4) gold-stibnite-cinnabar. The ore formation occurred at medium and low temperatures and pressures over a wide range of depths. The large vertical extent of ore mineralization is related to long-term uplift of the ore-hosting blocks during hydrothermal ore formation. The large disseminated gold-sulfide deposits are directly related to zones of antimony and mercury mineralization. The formation of disseminated ores lacking typical vertical zoning is related to the primary influence of hydrocarbon fluid with subsequent hydrothermal transformation. The total amount of metals in the black-shale sequences can be easily remobilized during metamorphic, magmatic, and hydrothermal processes in zones of tectonomagmatic activation (TMA) to form veinlet-disseminated and vein deposits. Isotopic studies indicate that the disseminated gold-sulfide deposits are related to crustal processes, but a portion of ore components could be derived from mantle sources.
