Zhenzhong Xiang

The Northwestern Guizhou Pb-Zn metallogenic area is a significant part of the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province. Orebodies of Pb-Zn deposits in this area are hosted in multi-layers of strata, structurally constrained by the thrusting fault-fold system and close spatially related to the Permian Emeishan basalt. However, there are still some controversies on the source of the ore-forming materials and the genesis of those deposits because of relatively limited researches. In this study, taking the Liangyan Pb-Zn deposit in the Northwestern Guizhou as research object, we have carried out the Pb isotopic analysis of sulfide minerals and C-O isotopic analysis and REE elemental analysis of ore-stage calcites from the deposit, aiming to elucidate the source of ore-forming materials and the genesis of the carbonate-hosted lead-zinc deposit in the northwestern Guizhou. The C-O isotopic data of calcites indicate that the carbon of ore-forming fluids was predominantly sourced from the dissolution of the Carboniferous carbonate host rocks with a minor contribution from organic matter within the sedimentary sequences. The oxygen was possibly derived from the hot basinal brine and ore-hosting carbonate rocks. The Pb isotopes of sulfide minerals and the REE compositions of calcites suggest that the ore-forming metals and rare earth elements within the ore-forming fluids were mainly originated from the binary mixture of the Mesoproterozoic Kunyang Group metamorphic basement and the ore-hosting Carboniferous carbonate rock. Combined with geological and geochemical characteristics of the Liangyan Pb-Zn deposit, it is suggested that the Liangyan deposit belongs to a thrusting fault-fold system-controlled MVT Zn-Pb deposit.