The Raigorodok stockwork gold-sulfide-quartz deposit in the North Kazakhstan gold ore province

The Raigorodok stockwork gold-sulfide-quartz deposit is located in the contact zone of a monzogabbro-diorite intrusion belonging to the Stepnyak complex (442 Ma). Two main ore formation stages have been established: early, with disseminated gold-bearing pyrite-chalcopyrite mineralization related to skarn, propylite, and K-feldspar formation, and late, with productive mineralization. The late stage was accompanied by the formation of beresite, sericite, and quartz and comprised two substages: (1) quartz-gold-pyrite-chalcopyrite mineralization and (2) quartz-carbonate-gold-polysulfide mineralization. The ⁴⁰Ar/³⁹Ar ages of beresites and sericites are 422.9 ± 4.3 Ma and 416.7 ± 4.3 Ma, respectively, which is 19-22 Myr younger than the age of the host intrusion. The deposit ores formed stepwise, at temperatures of 112-335 °C and fluid salinity of 0.7-21.2 wt.% NaCl equiv. Sulfur for skarns, propylites, beresites, and ores might have been provided by a deep magma chamber, and the carbonaceous shales of the Vendian Sharyk Formation might have been the source of gold. The isotope and geochemical data and the results of fluid inclusion study suggest that Raigorodok is an intrusion-related deposit. At the same time, the deposit has a number of signs of porphyry-epithermal ore-magmatic systems.