Faculty of Earth Resources, China University of Geosciences, Wuhan 430074, China

Touponao mercury-zinc deposit lies in the southeastern margin of Yangtze block, which is controlled by NW trending fault. The ore-hosting rocks are aplite-dolomites from the third member of Middle Cambrian Aoxi Formation. Ore minerals mainly consist of sphalerites and cinnabars, while the gangue minerals comprise quartz, dolomite and calcite. The fluid inclusions in ores are mainly pure liquid inclusions, partially gas-liquid two-phase inclusions and a few pure gas inclusions. The ore-forming fluid is characterized by medium-low temperature(84.3��~183.9��), middle-high salinity(6.16 wt%~22.24 wt%NaCl)and medium-high density(0.97~1.10 g/cm³). The gas composition analysis shows that it consists of CH₄, a small amount of N₂ and CO₂, the liquid component is H₂O, and the ore-forming fluid is hydrocarbon-enriched. The hydrogen and oxygen isotopic compositions are ��D (-105×10^-3~-46×10^-3) and ��¹⁸O_H2O (-7.1×10^-3~11.4×10^-3), indicating that the ore-forming fluid is mainly formation water, with some meteoric water. According to the geological background of mineralization, fluid characteristics, fluid sources and regional metallogenic characteristics, the authors suggest that mercury mineralization event is resulted from the long-term and durative tectonic movement in the Yangtze fold belt.