Abstract:
Located in the southwest of the western Hubei to western Hu'nan metallogentic belt, lead-zinc deposits in western Hu'nan are expected to become the largest lead-zinc deposit basement, with good ore-forming geological background and ore-bear-ing conditions.In this paper, S-Pb isotope compositions of sulfide minerals separated from orebodies in the ore deposits were deter-mined so as to discuss the sources of ore-forming materials.Studies of sulfur and lead isotopic compositions show that the sulfur isoto-pic compositions δ
34S in orebodies in western Hu'nan Province are in a wide range of 6.3‰~34.66‰, 19.64‰ on average, with obvi-ous rich heavy sulfur and the characteristics of the distribution of the Twin Towers.Sulfur of the ore mainly came from the marine sul-fate in the ore-bearing formation and seawater.The
206Pb/
204Pb,
207Pb/
204Pb and
208Pb/
204Pb ratios for ore minerals from the eight depos-its are in the ranges of 17.689~18.295, 15.535~18.848 and 37.294~38.630 respectively.As for lead-zinc deposits in this area, lead isoto-pic composition has orogenic belt and upper crust Pb isotopic characteristics, sources of ore-forming materials were from the mixture of orogenic belt and upper crust, lead genetic types are the subduction lead resulting from mixture of upper crust and mantle magma-tism.The authors put forward the lead-zinc ore-forming model of two stages of evolution for deposits of western Hu'nan area.Leadzinc mineralization in the area went through two phases of evolution which included enrichment of ore-forming fluid and migration of ore-forming fluid.