Fluid Inclusion Characteristics and Metallogenic Model of the Aqishan Pb-Zn (Cu) Deposit, Shanshan County, Xinjiang

The Aqishan Pb-Zn (Cu) deposit is a newly discovered large-scale Pb-Zn(Cu) deposit in the western section of the Jurassicta metallogenic belt in eastern Tianshan Mountains,with the potential of super-large deposits. Based on the analysis of the geological characteristics of the deposit,the ore minerals (sphalerite,quartz,calcite,garnet) in the main ore-forming stage were tested by fluid inclusion temperature and salinity. The results show that the inclusions are mainly two-phase of gas-liquid; three-phase inclusions containing seed crystals are few. The gas-liquid ratio in gas-liquid two-phase inclusions is 5%~10%,and the uniform temperature is 94.8~440.1°,the salinity is 4.8%~44.32% respectively. Sphalerite is obviously divided into high-temperature sphalerite (331℃) and low-temperature sphalerite (145~181℃). Salinity is mainly distributed in 8~14% and 18~22%.The study of fluid inclusions,combined with the geological and geochemical research of the deposits,shows that The Aqishan Pb-Zn (Cu) deposit mainly exists in the early stage of silicate hydrothermal fluid and in the late stage of carbonate hydrothermal fluid. The interacted part of the two is the main ore-forming stage, with the characteristics of low-temperature and medium salinity in the ore stage,and thus summarizing the ore-forming model of the deposit.