Abstract: Studies on fluid inclusions in sphalerite, calcite, dolomite, and quartz from Shizishan lead-zinc deposit, Limei lead-zinc deposit, Naizibao lead-zinc deposit, Chatian lead-zinc deposit, Dagoudong lead-zinc deposit, Dongjiahe lead-zinc deposit, Tangjiazhai lead-zinc deposit in western Hunan, Bingdongshan lead-zinc deposit and Aizigang lead-zinc deposit in western Hubei, through the analysis of homogenization temperatures, salinity, gas compositions, liquid compositions by heating/freezing system, Laser Raman and Ion Chromatography, show that the temperature of ore-forming fluid is 80-230°C, the salinity is always greater than 15%, the density is greater than 1g/cm3, and the mineralization pressure is about 223×105-777×105Pa. The ore-forming fluid is highly concentrated solution containing mainly sodium and calcium chloride. It belongs to the low temperature, high salinity, high density and mineralized underground hot brine. The cations in ore-forming fluid are mainly Cl-, Na+, Ca2+, K+, Mg2+. The composition of hydrogen and oxygen isotopes show that the origin of ore-forming fluid is related to construction water, with possible infiltration of rainwater and little metamorphic water. There is organic matter in the fluid inclusions. CH4 is widespread in the fluid inclusions. Mineralization is probably related to organic matter. The organic matter in the ore-controlling structure leads to the reduction of sulfate and the deposition of lead and zinc ore. The homogenization temperatures of ore-forming fluid from typical lead-zinc deposits in Sichuan, Yunnan, Guizhou district is 90-280°C. The studied lead-zinc deposits in western Hunan and western Hubei show similar low temperatures and MVT. The lead-zinc deposits in both regions may be controlled by the same tectonic dynamics.

Key words: MVT-type lead-zinc deposits;ore-forming fluid;low temperature;western Hunan-western Hubei