Abstract:Based on such means as systematic petrographical study, microthermometry, and Raman probe analysis, the authors revealed that homogenization temperatures of fluid inclusions in vein quartz from the Xiongcun copper_gold deposit vary from 121℃ to 382℃, mainly in the range of 150℃~250℃. Homogenization pressures of fluid inclusions vary from 1.94×105 Pa to 45.92×105 Pa.Fluid inclusion salinities at the stage of copper mineralization vary in a widerange from 1.23 wt%NaCleq. to 36.61wt%NaCleq., and are distributed in three discontinuous domains. High-salininity fluids existed at the stage of copper mineralization, but gold mineralization was related to low temperature and low salinity fluids. Fluid temperature and pressure characteristics of the Xiongcun deposit coincide with those of epithermal type deposits, but the salinity of the former deposit is higher than that of typical epithermal deposits. Ore-forming fluids of the Xiongcun deposit are rich in Ca2+, CO2, N2 and CH4,thus belonging to the Na+ -Ca2+ -K+ -Cl- -SO2 -4 system. During the ore-forming process, there existed at least three fluid end_members in the Xiongcun deposit, namely the CO2-N2-CH4-rich member, the low-salinity aqueous member, and the high-salinity aqueous member. Ore-forming fluids of the Xiongcun deposit formed a complex immiscible system, and fluid immiscibility seems to have been one of the important mechanisms for metallic deposition in the Xiongcun deposit. The Xiongcun copper-gold deposit is a peculiar epithermal deposit, which show some typical characteristics of both high-sulfidation epithermal deposits and low- sulfidation epither-mal deposits.