ORE-FORMING FLUID CHARACTERISTICS AND IMPLICATION OF ANTIMONY DEPOSITS IN CENTRAL JILIN PROVINCE: A Case Study of Datudingzi, Zhilin and Xingfutun Antimony Deposits

A series of gold, antimony and copper-nickel deposits are distributed in central Jilin Province with favorable metallogenic geological conditions. The study of microscopic temperature measurement and stable isotopes(H, O and S) for the quartz fluid inclusions in the major metallogenic period of stibnite in Datudingzi, Xingfutun and Zhilin antimony deposits shows that there are three main types of fluid inclusions including Type-Ⅰ of liquid-rich two-phase(L_H2O+V_H2O) inclusion, Type-Ⅱ of pure liquid phase(H₂O) inclusion, and Type-Ⅲ of gas-phase inclusion, with the homogenization temperature of 121.5-281.5℃, salinity of 3.39%-10.73%, and estimated density of 0.833-0.985 g/cm³. The ore-forming fluid is characterized by low-medium temperature, low salinity and low density. The H-O isotopic composition characteristics show that δ¹⁸O is 15.71‰-18.28‰, and δD from -111.1‰ to -83.8‰. The ore-forming fluid is dominated by magmatic hydrothermal fluid, mixed with later atmospheric precipitation. The δ³⁴S of pyrite ranges from -8.25‰ to -3.86‰, and that of stibnite from -8.18‰ to -7.67‰. The range of δ³⁴S values is relatively concentrated, obviously different from magmatic sulfur. The metallogenic materials are mainly derived from the crust. The zircon U-Pb dating results reveal that the crystallization ages of the intrusive rocks are 205±2.7 Ma, 192±1.9 Ma and 195±1.9 Ma respectively. The formation of antimony deposit is closely related to magmatic hydrothermal fluid, aged in Late Triassic-Early Jurassic. The antimony deposits in central Jilin Province are of epithermal-mesothermal type genetically.