The mineral composition and formation conditions of quartz-beryl mineralization of the Pervomaiskoe molybdenum deposit, Dzhida ore field, Southwestern Transbaikalian region

The article is devoted to determination of the mineral composition, physicochemical parameters, and sources of the substance of quartz-beryl mineralization of the Pervomaiskoe ore deposit, that is distinguished as an independent stage of the mineral formation. The main minerals are quartz and beryl; phenakite has first been identified for the Pervomaiskoe deposit. Ore minerals are represented by molybdenite, pyrite, and rare grains of cassiterite, chalcopyrite, rutile, aikinite, wulfenite, columbite, monazite, and xenotime. Results of studying the fluid inclusions have showed that homogenization temperatures of the fluid inclusions in the beryl vary in the range from 265 to 191°C. The ore-forming solutions are characterized by a low salinity of 5.9-8.6 NaCl equiv. Homogenization temperatures of fluid inclusions in the quartz correspond to 281-250°C. Data on the isotopic composition show the participation of meteoric waters in the ore-forming process.