Sulfur and Lead Isotopic Geochemistry of the Shidi Pb-Zn Deposit in Xiushan County, Chongqing

摘要

The Shidi Pb-Zn deposit is located in Xiushan County, southern Chongqing, and its orebodies were hosted in marine carbonates of the Cambrian Pingjing Formation. The authors selected sulfide minerals from the deposit for the analysis of sulfur and lead isotopic compositions. Theδ~(34)S values of sulfide minerals vary from 10.8‰ to 15.6‰, with an average value of 13.52‰, indicating these sulfide materials were mainly derived from marine sulfate reduction. The ~(206)Pb/~(204)Pb, ~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb ratios for sulfide minerals vary within the ranges of 18.319 - 18.422, 15.740-15.784 and 38.355-38.511, respectively. In the diagrams of Zartman, the Pb isotopic compositions of sulfide minerals fall into the regional upper crust lead zone. According to the characteristics of sulfur and lead isotopic compositions of the Shidi Pb-Zn deposit, the ore-forming materials might have come from the black shales of the Lower Cmabrian Niutitang Formation.