Sulfur and lead isotopic compositions of ores from the Dengying Formation and their prospecting implications in the Huize Pb–Zn deposit, Yunnan Province

The giant Huize lead-zinc deposit is situated at the core area of the Sichuan-Yunnan–Guizhou lead-zinc metallogenic province. The mineralization is mostly hosted in the dolomite of the Lower Carboniferous Dapu Formation and minor orebodies occur in the dolomite of the Upper Devonian Zaige Formation. The mineralization has been newly discovered in the dolomite of the Upper Sinian Dengying Formation. In this paper, on the basis of detailed field investigation and microscopic observation on ore minerals, we conducted systematic LA–MC–ICP–MS sulfur and lead isotopic analyses on sulfides from ores hosted in the Dengying Formation. The δ³⁴S values of the sulfides have two variation ranges, which are －29.6‰~－22.2‰ and +6.3‰~+18.8‰, respectively. The results indicate that most of the sulfur was sourced from thermal reduction of marine sulfates in the carbonates, and a little of the sulfur was generated from bacterial sulfate reduction. The ratios of ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, ²⁰⁸Pb/²⁰⁴Pb vary in narrow ranges of 18.480~18.909, 15.714~15.747, 38.427~38.959, respectively, which suggests a single source or multiple sources with homogeneous mixing and an upper crust source for the lead. In combination with previous studies, and geological and geochemical characteristics, we suggest that the Huize lead-zinc deposit should be assigned as a MVT deposit. The ores hosted in the Dengying Formation imply a good prospecting potential in the Dengying Formation.