Abstract: The Jinchang copper-gold deposit in Dongning Country, Heilongjiang Province, is a superlarge deposit in eastern Jilin-Heilongjiang, mainly developing three types of ore bodies: Cryptoexplosive breccia type, veinlet disseminated type, and fracture-filling type. Among them, the breccia type and veinlet disseminated type orebodies together consitutec a hydrothermal Cu-Au mineralization system with a shallow epithermal high-sulfidation type and a deep porphyry type. This paper focuses on the J-0 breccia type Cu-Au ore body, the J-1 breccia type Au ore body, and No.18 veinlet disseminated ore body. Through microthermometrry of fluid inclusions, laser Raman microprobe, rare gas isotope analysis, hydrogen-oxyen isotope analysis, with latest geochronological results, the properties, origin, and evolution of these ore-forming fluids in this copper-gold hydrothermal deposit are systematically studied. The underlying mantle-derived magma forms high-salinity, highly oxidizing Cu-rich metallogenic fluids through primary boiling. During the ascent process, these fluids undergo secondary boiling and react with the surrounding rocks, forming the J-0 breccia type copper-gold ore body in the shallow cryptovolcanic zone and the No. 18 disseminated veinlet type copper-gold ore body in the deep fracture filling zone. The addition of late atmospheric precipitation further promotes the precipitation of residual metallogenic elements. The magma chamber in the shallow crust directly exsolves high-salinity ore-bearing fluids. During the ascent of this fluid to the shallow crust and reaction with the surrounding rocks, the decrease in temperature and pressure leads to the precipitation of a large amount of gold and other metallogenic elements in the breccia and cement, forming the J-1 breccia type gold ore body.

Key words:  fluid inclusion, noble gas istope, hydrogen and oxygen isotope, metallogenic system；Jinchang copper-gold deposit, Heilongjiang Province