Metamorphogenic-Magmatogenic Ore Formation in the Sovinoe Gold-Quartz Deposit (Northern Chukotka)

摘要

The formation of gold-quartz deposits in the Russian Northeast, primarily related to geodynamic constraints of accretion and orogenesis, characterizes the early stage of ore accumulation in the region. Ore mineralization is widespread in Upper Paleozoic folded rock sequences and is partially regenerated at outer contacts of Mesozoic granitoid massifs. The gold-quartz deposits have the following typomorphic features: (1) their location is mainly controlled by folded structures and fields of zonal metamorphic rocks; (2) the monotonous section of ore-hosting sequences is composed of major (often calcareous) sandstones and subordinate siltstones and shales; (3) magmatic rocks are absent or subordinate in ore fields; (4) ore mineralization is confined to the transitional (sandstone-silt-stone or carbonate-terrigenous) zones of sections; (5) orebodies make up echelons of saddle-shaped veins on limbs and hinges of linear folds and flexures (ore-bodies are less often controlled by faults); (6) laminated structures are widespread (e.g., quartz with the specific book-type structure); (7) the mineral composition of ores is relatively simple (arsenopyrite, pyrite, pyrrho-tite, galena, tetrahedrite, sphalerite, and gold with a fineness of 820-850); and (8) orebodies are accompanied by large gold placers.