Genesis of the Maoping carbonate-hosted Pb–Zn deposit,northeastern Yunnan Province,China:evidences from geology and C–O–S–Pb isotopes

作者：Yufan He,Tao Wu,Zhilong Huang,Lin Ye,Ping Deng,Zhenzhong Xiang

摘要：The Maoping Pb-Zn deposit(~3 Mt Pb+Zn reserves with grades of 12-30 wt%)is one of the largest Pb-Zn deposits in the Sichuan-Yunnan-Guizhou(SYG)metallogenic province,which has contributed a tremendous amount of lead and zinc resources for China.To obtain a further understanding of the sources of ore-forming materials and ore genesis of the deposit,S-Pb isotopes of sulfides and C-O isotopes of ore-stage calcites were systematically collected from representative orebodies at different elevations with a Finnigan MAT-253 mass spectrometer.The calcites separated from the sulfides of the NoⅠand NoⅡorebodies shared identical b13 CPDB values(-5.3 to-0.8‰)andδ18OSMOW values(+14.5 to+21.8‰)with those of the calcites in the SYG region,suggesting that CO2 in regional ore-forming fluids possibly had a homologous C-O source that originated from a ternary mixture of the dissolution of marine carbonate rocks,degassing process of the Emeishan mantle plume,and dehydroxylation of sedimentary organic matter.The No.Ⅰ-1 and No.Ⅰ-2 orebody was hosted in the same strata,but the sulfur source of No.Ⅰ-1 orebody(+13.1 to+19.0‰)with equilibrated sulfur fractionation(δ34Sspbaierite-<δ34Sgalena)and No.Ⅰ-2 orebody(+18.0 to+21.8‰)with sulfur equilibrium fractionation(δ34Sspnaierite>δ34-Sgalena)were different.They were derived from the allopatry thermochemical sulfate reduction(TSR)of overlying Carboniferous sulfates in the ore-hosting strata and local TSR of sulfates in the ore-bearing Upper Devonian Zaige Formation,respectively.The narrow and uniform Pb isotopic ratios of single galena grains collected from sulfides with 206Pb/204Pb of 18.713-18.759,207Pb/204Pb of 15.772-15.776 and 208Pb/204Pb of39.383-39.467 indicate a well-mixed metal source(s)that consist of Proterozoic Kunyang and Huili Group basement rocks and Devonian to Middle Permian ore-hosting sedimentary rocks.Besides,the late Permian Emeishan basalts are difficult to contribute metals for regional Pb-Zn mineralization despite a closely spatial relationship w

发文机构：State Key Laboratory of Ore Deposit Geochemistry University of Chinese Academy of Sciences.Beijing 100049 Yiliang Chihong Mining Co.

关键词：MaopingPb–ZndepositOre-formingmaterialsOregenesisMVT-likedeposit

分类号： P61[天文地球—矿床学]