Silver and Sulfosalt Minerals in Tungsten Deposits,South China

Silver occurs in South China wolframite-quartz veins in three forms:(1) as micro inclusions of Ag_2S and AgBiS_2,(2) as argentite and matildite as a result of exsolution from galena and (3) as Ag-bearing sulfosalts and independent silver minerals. According to mineral assemblages the Ag-bearing tungsten deposits are classified as two types:(1) Ag-bearing W-Bi deposits in eastern Nanling,where gnstavite has been found and (2) Ag-bearing W-Sn(Sb) deposits which are mainly distributed in western Nanling.The authors consider that the enrichment of silver and sulfosalt minerals in the lower parts of pneumato-hypothermal tungsten deposits is the result of reversed vertical zoning caused by high concentrations of F and S in the ore-forming fluids.