Quartz reef from gold occurrences in riphean deposits of the Avzyan ore region (South Urals): min-eralogical and thermocriometric features

Quartz reefs from the gold-sulfide-quartz deposit Gorny Priisk and gold-quartz sulfide bearing ore occurrences Ulyuk-Bar and Vostochno-Aktashskoe have the similar temperatures of homogenization of primary fluid inclusions (228-382 ° C) and salt composition, in which magnesium and potassium chloride predominate. Salinity varies in the range of 5,4-15,8 wt. % NaCl equiv. Generation of gold- bearing quartz reefs was caused by the migration of magmatogene fluids connected with the tectono-thermal stage between the Middle and Late Riphean. Barren vein quartz from the host Riphean rocks is characterized by lower temperatures of homogenization (128-238 ° C), predominance of the iron chlorides in salt composition and higher salinity (12,9-22,8 wt% NaCl equiv.). The generation of quartz in the gold-sulphide ore occurrence Bogryashka, which have temperatures of homogenization of 152-292 ° C and the predominance of calcium and magnesium chlorides in the salts, is associated with the pre-ore process of magnesian-ferruginous metasomatism.