Abstract:

The systematic petrographic，microthermometric as well as laser Raman microspectroscopic studies on fluid inclusions developed in auriferous quartz veins collected from Wulong gold deposit were carried out.The results show that there exist three types of primary fluid inclusions in vein quartz minerals，CO2±CH4、H2O-CO2±CH4 and aqueous twophase respectively. The microthermometric research of different kinds of fluid inclusions reveals that the homogenization temperatures of H2O-CO2±CH4 type fluid inclusions range from 287.8℃ to 382.5℃，the salinities are between 0.42%[CD*2]4.87%NaCl. The homogenization temperatures of two-phase aqueous fluid inclusions vary from 198.5℃ to 338.4℃，and the salinities between 2.24%-6.88%NaCl.The composition of gaseous phases in there types of fluid inclusions are dominated by CO₂ and CH₄，with largely variable relative content. By comprehensive studies，the conclusion can be drawn that the oreforming fluid of auriferous quartz veins in Wulong gold deposit belongs to the medium temperature，low salinity and CO2-bearing solutions. It was derived from magmatic activities and experienced reaction with country rocks during their transportation and accumulation processes，which resulted in the release of CH₄ into solutions and formation of mineralizing fluids enriched in CO₂ -and CH_-4.

Key words: Wulong gold deposit, geological feature, ore-forming solution, geochemistry, Liaoning Province