Research on fluid inclusions of the Yinshan polymetallic deposit, Jiangxi Province, China

In this paper some new advances in the study of fluid inclusions of the Yinshan deposit in Jiangxi Province, China, are presented. The fluid inclusions of the deposit can be divided into four types: 1) gas-rich inclusions; 2) liquid-rich inclusion; 3) salt-saturated H₂O inclusion; and 4) single-phase or multiphase CO₂-rich inclusion. Homogenization temperatures of the fluid inclusions range from 100 to 520°C, mainly in the range 120–400°C. The daughter crystal-bearing multiphase inclusions present in quartz porphyries (including Nos. 13 and 4 dikes) have been observed. In ore veins, some daughter crystal-bearing multiphase inclusions have been observed, too. On the basis of the results of fluid inclusion research, the authors suggest that the ore-forming fluid must have a close genetic relation to magmatic hydrothermal solution. The ore-forming fluid was dominantly originated from the depth and the mixing of magmatic solution with meteoric water was enhanced during ascending of the fluid, accompanying immiscibility and boiling of fluid. There may be a concealed igneous body at the depth of the Yinshan deposit, which furnishes the scientific basis for metallogenic prognosis at the depth of the Yinshan deposit. This research project was supported financially by the National Natural Science Foundation of China (No. 49633120, No. 49773196), and the State Key Laboratory Foundation of Metallogeny of Endogenetic Metallic Deposits of Nanjing University.