Sulfur and Lead Isotope Composition and Tracing for the Sources of Ore-Forming Materials in the Mengya'a Pb-Zn Deposit,Tibet

The Mengya'a lead-zinc deposit in Tibet is located in the eastern section of Gangdise metallogenic belt.The ore body mainly occurs as stratoid form in the skarn and skarnization marble of the Middle Carboniferous-Upper Permian Laigu Formation,distributed nearly E-W direction.Based on analysis of the ore-forming geological conditions,this paper studies systematically the composition characteristics of S,Pb isotopes in the ore and discusses the sources of the ore-forming materials.Studies have shown that the composition of S isotope in ore sulfides has a narrow variation range and a tower distributional effects.The δ34S∑S of the ore-forming hydrothermal system is about 5.2‰,which presents a characteristic of sulfur from magmatic origin.The Pb isotopic composition of ore sulfides is stable and the ore lead is ordinary common lead.Ore lead derived from magma,which came from partial melting of the upper crust in Early Cretaceous.