The Jinchang gold deposit, located in Dongning County, Heilongjiang Province, is a giant deposit that has been discovered recently, with resource up to 86 tons of gold. Occurring in the Jilin-Heilongjiang Metallogenic Belt in the eastern Central Asia Orogenic Belt, it is a complex ore-system possibly including porphyry-, explosive breecia- and epithermal-styles. The ore-system is associated with Mesozoic intermediate-acidic volcanic-subvoicanic rocks. The J0 orebody is regarded to be of explosive breccia-type. Studies in ore geology and isotope and fluid inclusion geochemistry show that the ore-forming process of the J0 orebody includes three stages, the early, middle and late stages, characterized by mineral assemblages of quartz-pyrite, quartz-polymetallic sulfides and quartz-carbonate, respectively. Most of the native gold grains are observed in the middle-stage minerals, and next in the early-stage pyrite. The initial ore-fluids were magmatic in origin and characterized by high temperature, high salinity, high oxygen-fugacity and high content of CO2. Fluid-boiling resulted in release of volatiles such as CO, and decrease in oxygen-fugacity, causing rapid precipitation of sulfides and native gold in middle stage. Meteoric water input made the late-stage fluids dilute, CO2-poor and epithermal, and slightly contribute to Au-mineralization. The J0 orebody of the Jinchang gold deposit is holistically an intrusion-related, shallow-developed (633m similar to 2736m), high salinity (11. 70% similar to 37. 81 % NaCl. eq) and medium-to-high temperature (238. 3 similar to 425. 7T) hydrothermal ore-system. The ore-system, characterized by high-content of CO2, must be developed in extensional regime of a thickened collisional orogen, instead of a magmatic are related to oceanic plate subduction.
