Study on the Ore-forming Fluid Characteristics and Process in Xiaoqinling Gold Deposit, Shaanxi Province

This papers ystematically studied the distribution characteristics and ore-forming stages of gold orebody in Xiaoqinling area of Shaanxi Province through microthermometry and Laser Raman spectroscopy.The physicochemical characteristics and ore-forming model of Xiaoqinling gold deposit were analyzed.Based on the previous analysis,the authors hold that the compound antiform of Dayueping-Jinluoban is the main ore-controlling structural framework.The distribution of orebody is controlled by the secondary embrittlement ductile faults derived from the compound antiform.The main ore-bearing structure is along the east-west fault zoneparallel to the fold hinge.The ore-forming process is divided into four main stages.It is in the mineralization stage (phase Ⅲ) that formed gold-bearing polymetallic sulfide deposits.The ore-forming fluidis of low salinity and rich in CO₂, with the metallogenic condition being medium temperature and medium pressure.The decrease of pressure by the expansion of mineralization space and the mixing of meteoric precipitation caused gold deposit precipitation.