Fluid inclusion studies of the Huangsha quartz-vein type tungsten deposit, Jiangxi Province
江西黄沙石英脉型钨矿床流体包裹体研究

The Huangsha tungsten deposit is an important large quartz-vein type W-polymetallic deposit in southern Jiangxi Province. Based on detailed petrographic observations and using the means of Fluid Inclusion Assemblage (FIA), we carried out microthermometric and Raman microspectroscopic studies of fluid inclusions in early wolframite-quartz veins and late sulfide-(wolframite)-quartz veins of the main ore-forming stage of Huangsha tungsten deposit. The fluid inclusions are mainly aqueous inclusions and carbon-aqueous inclusions in wolframite-quartz veins and only aqueous inclusions in sulfide-(wolframite)-quartz veins. Experimental results show that the aqueous inclusions decrease in homogenization temperature from the early veins to the late veins at constant salinity. Raman microspectroscopic studies of the fluid inclusions show that, the main component of aqueous inclusions in wolframite-quartz veins and sulfide-(wolframite)-quartz veins is H2O, whereas those in wolframite-quartz veins are major H2O, minor CO2, and rare CH4 and N2. The characteristics of fluid inclusions in the Huangsha tungsten deposit indicate that the fluid immiscibility caused by CO2 escaping possibly led to metals precipitation in the wolframite-quartz veins and the fluid mixing led to metals precipitation in the wolframite-quartz veins.