New Data on the Conditions of the Formation of Gold Mineralization in the Drazhnoe Deposit, the Republic of Sakha (Yakutia): Evidence from the Study of Fluid Inclusions

AbstractNew results of thermobarogeochemical studies show that quartz veins in the Drazhnoe deposit were formed under mesozonal conditions at a depth of 3–9 km from heterogeneous carbon dioxide–aqueous fluids with a low concentration of brines and high contents of CO2, which is typical of ore-forming fluids in orogenic vein gold deposits. Based on the phase composition, three types of fluid inclusions are distinguished: (1) carbon dioxide–aqueous; (2) gaseous, filled with dense carbon dioxide; and (3) a two-phase gas–liquid of aqueous–brine solutions. Na, Mg, and Fe chlorides predominated in the ore-forming fluids. It is assumed that the fluids migrated along the regional Adycha–Taryn shear zone and were uplifted to the Earth’s surface at a supra-lithostatic pressure, which was followed by precipitation of ore elements and the formation of quartz veins during tectonic movements along shear zones.