Geological characteristics and ore genesis of the Xi-angshansi Pb-Zn deposit, Jinshan County, Hubei Province

The Xiangshansi Pb-Zn deposit, located in Jinshan County, Hubei Province, is hosted in the upper Sinian Dengying formation and the lower Cambrian Zhuanggouzi formation. The mineralization can be divided into two types, carbonate-type and carbon-bearing shale-type. Pb-Zn mineralization is controlled by the northwest-ward structures. The nearby Xiangfan-Guangji deep fault controls the formation and transportation of the ore-forming fluid and is a conducting structure. The subordinate northwestward faults and fractures are host structure. Results of fluid inclusion show that the ore-forming fluid belongs to NaCl-MgCl2-H2O system with the salinity between 9.47~9.98 wt%NaCleq and homogenized temperature 90~128℃, which indicates a minima trapping pressure and depth between (375.52 ~ 400.31) ×105 Pa and 1.25 ~ 1.33 km, respectively, and a low-temperature epithermal deposit. Theδ34SCDT composition of galena spans-0.47‰~10.16‰with a range of 10.63 ‰and an average of 6.99 ‰. The composition of lead isotopes 206Pb/204Pb ranges from 17.842 ~ 17.976 (average 17.923); 207Pb/204Pb 15.577~15.59 (average 15.586); 208Pb/204Pb 37.786~37.867 (average 37.834). Theμvalues are between 9.47 ~9.51, averaging 9.49 and Th/U 3.69 ~ 3.7, averaging 3.72. Those combined evi-dence indicate ore-forming materials are mainly from deep source associated with orogenesis, and Pb-Zn deposit is subjected to structurally controlled filling type.