Sources of the Laoxiongdong carbonate-hosted Pb–Zn deposit in Southwest China:constraints from S–Pb–Zn isotopic compositions  

作　　者：Wenyuan Wang Jianguo Gao Keyong Wang Yangxia Nong 

机构地区：[1]College of Earth Sciences,Jilin University,Changchun 130061,China [2]Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China [3]Kunming Metallurgical Research Institute,Kunming 650031,China

出　　处：《Acta Geochimica》2020年第5期717-732,共16页地球化学学报（英文）

基　　金：financially supported by the National Natural Science Foundation of China(No.41272111)。

摘　　要：The Sichuan-Yunnan-Guizhou(SYG)Pb-Zn mineral province,which has significant Pb-Zn repositories in China,is situated in the western Yangtze Block.Despite decades of research,the Pb-Zn source of deposits is still disputed between the basement rocks,sedimentary wall rocks,or the Emeishan flood basalts.The newly-discovered Laoxiongdong Pb-Zn deposit is hosted by the Late Ediacaran Dengying Formation in the SYG province.Moreover,the Laoxiongdong orebodies lie between regional deep faults and close to the Proterozoic basement and Emeishan basalts.Hence,this deposit represents a good case study on the ore-forming material source for the regional Pb-Zn mineralization.The Laoxiongdong Pb-Zn ores are massive,vein,or disseminated and have mainly sphalerite,galena,pyrite,quartz,and calcite.In this paper,we present new sulfide S-Pb-Zn isotope data of the deposit.The sulfideδ34SCDT values(+11.8 to+16.5‰)suggest that the reduced sulfur was mainly sourced from evaporites in the Late Ediacaran-Cambrian sequences.Pb isotopic ratios(206Pb/204Pb=18.004-18.107,207Pb/204Pb=15.652-15.667,and 208Pb/204Pb=38.037-38.248)suggest that the lead metal was primarily originated from the basement rocks.The sphaleriteδ66Zn values(+0.16 to+0.37‰)are also highly similar(within error)to those of basement rocks(+0.10 to+0.34‰),suggesting a basement-rocks zinc source with minor contributions from the carbonate host rocks and Emeishan flood basalts.The narrow sphalerite Zn isotopic range(0.21‰)also indicates that the Zn isotopic fractionation between the sphalerite and initial fluid was limited during the sphalerite ore precipitation.Therefore,we propose that both the Late Ediacaran Dengying Formation rocks and Proterozoic basement rocks were important ore-forming material source for the Laoxiongdong deposit,whereas the Emeishan flood basalts represent only a minor ore-material source.

关 键 词：S–Pb–Zn isotopes The Laoxiongdong Pb–Zn deposit Sichuan–Yunnan–Guizhou Pb–Zn mineral province Southwest China 

分 类 号：P618.4[天文地球—矿床学] P597[天文地球—地质学]