Earth Science Frontiers ›› 2018, Vol. 25 ›› Issue (1): 125-137.DOI: 10.13745/j.esf.yx.2017-10-4

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Sources of oreforming material of typical PbZn deposits in the SichuanYunnanGuizhou metallogenic province: constraints from the SPb isotopic compositions

KONG Zhigang,WU Yue,ZHANG Feng,ZHANG Changqing,MENG Xuyang   

  1. 1. School of Earth Science and Resources, Chang’an University, Xi’an 710064, China
    2. Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China
    3. College of Resources and Environment, Yangtze University, Wuhan 430100, China
    4. School of Earth Sciences and Resources，China University of Geosciences(Beijing), Beijing 100083, China
    5. MLR Key Laboratory of Metallogeny and Mineral Assesment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
  • Received:2017-01-01 Revised:2017-05-10 Online:2018-01-15 Published:2018-01-15

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Abstract: The SichuanYunanGuizhou (ChuanDianQian) PbZn metallogenic province, located along the western margin of the Yangtze block, comprises more than 400 ore deposits or prospects. The average Pb and Zn grades of its 200 Mt ore reserve are 5 and 10 wt%, respectively. The PbZn ore bodies mainly distributed as stratoid or veintype within the Sinian to Permian carbonate rocks, suggesting a typical epigenetic PbZn mineralization. In this study, isotope data of S and Pb sulfides from 21 deposits were compiled to reveal the source of oreforming materials, and provide guidance for further prospecting. The δ34S values of most sulfide minerals range from +9.0‰ to +28.6‰, similar to the SiniantoPermian seawater sulfate (+8.0‰ to +38.7‰). It suggests that S in sulfides mainly came from thermochemical sulfate reduction (TSR) of the hoststrata seawater sulfate. In addition, thermal decomposition of sulfurbearing organic matter could provide part of reduced sulfur in mineralization in some PbZn deposits. The Pb isotopic compositions of sulfides in the research area indicate four possible Pb sources: (1) Pb of the Tangjia deposit originated mainly from the basement rocks; (2) Pb in the Jinshachang, Lemachang and Lehong deposits mainly came from basement rocks containing radiogenic Pb isotopes and cap rock organicrich sediments; (3) Pb of the Huize, Tianbaoshan, Maozu, Yinchanggou, Daliangzi, Yunluhe, Maoping, Fule, Shanshulin and Tianqiao deposits originated primarily from basement rocks and oreforming fluid of multiple metalbearing brine mixing in the cap stratum, and partly from Permian Emeishan basalt; (4) Pb of the Qingshan, Chipu, Yinchangpo, Shaojiwan and Banbanqiao deposits mainly came from sedimentary rocks, and partly from basement rocks. The multiple SPb isotope composition in typical PbZn deposits is indicative of mixed origin for oreforming materials in the metallogenic province.

Key words: SichuanYunnanGuizhou, PbZn deposit, oreforming material, S isotopic composition, Pb isotopic composition

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