Genesis of the Sinongduo carbonate‐hosted Pb–Zn–Ag deposit in the central Lhasa terrane, Tibet

The Sinongduo mining region includes two types of mineralizations:the epithermal and the carbonate-hosted Pb-Zn-Ag deposits.Despite being studied for many years,the ore formation process and genesis of the carbonate-hosted Pb-Zn-Ag deposits remain poorly understood.The Pb-Zn-Ag ore bodies occur as veins and are hosted by limestone and dolostone of the Permian Xiala Formation.Three sulfide mineralization substages have been identified at the Sinongduo carbonate-hosted deposit.Indium coupled with Cu,Co and Sn was incorporated into sphalerite as substitutions:2Zn2+? Cu++In3+,(3n/2+1)Zn2+? Co2++nIn3+or(2n+1)Zn2+? Co2++n(Cu++In3+)(n>1)and 4Zn2+? Sn2++2In3+.Sphalerite and pyrite in the mineralization stage display δ34S values in a narrow range of+5.7‰ to+11.3‰,which are similar to those of Palaeocene igneous rocks,indicative of a magmatic source of sulfur.We present systematic carbon-hydrogen-oxygen isotope results that further support a magmatic source for the ore-forming fluids that were influenced by meteoric water.Furthermore,the Pb isotope compositions of sulfide minerals in the Sinongduo carbonate-hosted deposit overlap with the values of coeval Linzizong volcanic rocks and are similar to those of Indian Ocean sediments,indicating upper crustal sources of metals.We conclude that the Sinongduo carbonate-hosted Pb-Zn-Ag deposit is a medium-to low-temperature magmatic-hydrothermal deposit related to Linzizong magmatism.