FLUID INCLUSION CHARACTERISTICS AND GENESIS OF SHIWULIQIAO GOLD DEPOSIT IN NORTHERN DAXINGANLING MOUNTAINS

The Shiwuliqiao gold deposit is located in the junction zone between the southern margin of Upper Heilongjiang Basin, the northern margin of Yaozhan fault depression and the southern margin of Ershierzhan uplift within the Upper Heilongjiang Au-Cu-Mo metallogenic belt. The metallogenesis of the deposit can be divided into four stages, i.e. I) vein pyrite-quartz stage, Ⅱ) disseminated pyrite±chalcopyrite-quartz stage, Ⅲ) disseminated pyrite±chalcopyrite±sphalerite±galena-quartz stage and IV) low sulfide-carbonate stage, among which the polymetallic sulfide-quartz is the main metallogenic stage. The study of fluid inclusions shows that gas-rich and liquid-rich fluid inclusions are developed in stages Ⅱ and Ⅲ. The fluid in stage Ⅱ is immiscible, with the homogenization temperature of 283-394 ℃ and salinity of 2.56%-7.99%, while the homogenization temperature in stage Ⅲ is 251-298 ℃ with the salinity of 2.56%-5.09%, belonging to simple NaCl-H₂O system. The H-O isotope indicates that the ore-forming fluid is dominated by atmospheric precipitation, and the S isotope suggests that the metallogenic materials mainly come from deep magmatic sulfur. The Shiwuliqiao gold deposit is of volcanic rock-hosted epi-mesothermal type.