地学前缘 ›› 2018, Vol. 25 ›› Issue (1): 125-137.DOI: 10.13745/j.esf.yx.2017-10-4

• 构造控矿与低温成矿作用 • 上一篇    下一篇

川滇黔地区典型铅锌矿床成矿物质来源分析：来自S-Pb同位素证据

孔志岗，吴越，张锋，张长青，孟旭阳   

  1. 1. 长安大学 地球科学与资源学院, 陕西 西安 710064
    2. 昆明理工大学 国土资源工程学院, 云南 昆明 650093
    3. 长江大学 资源与环境学院, 湖北 武汉 430100
    4. 中国地质大学(北京) 地球科学与资源学院, 北京 100083
    5. 中国地质科学院 矿产资源研究所 国土资源部成矿作用与资源评价重点实验室, 北京 100037
  • 收稿日期:2017-01-01 修回日期:2017-05-10 出版日期:2018-01-15 发布日期:2018-01-15
  • 作者简介:孔志岗（1980—），男，博士研究生，讲师，从事区域成矿学研究。 E-mail：27245881@qq.com
  • 基金资助:
    国家重点基础研究发展计划“973”项目（2014CB440903）；国家重点研发计划项目（2017YFC0602502）；国家自然科学基金项目（41402063，41672093）；长江大学青年人才基金项目(2015cqr15)

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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摘要： 川滇黔铅锌矿集区位于扬子地块西南缘，发育有400多个矿床（点），铅锌矿石储量超2亿t，Pb平均品位(质量分数)达5%，Zn平均品位达10%。矿体主要呈似层状、脉状赋存于震旦系—二叠系碳酸盐岩地层中，为碳酸盐岩容矿后生铅锌矿床。文中通过综合分析川滇黔矿集区21个典型矿床的SPb多元同位素数据，示踪成矿元素主要来源，并为进一步找矿提供指导。研究区大部分铅锌矿床硫化物的δ34S值介于9.0‰～28.6‰之间，与震旦系—二叠系地层中海水硫酸盐δ34S值（+8.0‰到+38.7‰）相似，暗示研究区铅锌矿床硫化物中的S主要来源于赋矿地层中海水硫酸盐，TSR作用是还原硫的主要生成机制。部分矿床中，含硫有机质热解可能是还原硫的另外一种生成机制。该区硫化物Pb同位素组成显示4种不同的成矿物质来源模式：（1）唐家等矿床Pb主要来源于基底岩石；（2）金沙厂、乐马厂、乐红等矿床Pb主要来源于基底富放射性成因Pb的岩层及盖层沉积岩中富有机质地层；（3）会泽、天宝山、茂租、银厂沟、大梁子、云炉河、毛坪、富乐、杉树林、天桥等矿床Pb主要来源于基底岩石和沉积盖层中多源流体的混合，峨眉山玄武岩可能提供少量成矿物质；（4）青山、赤普、银厂坡、筲箕湾、板板桥等矿床Pb主要来源于沉积盖层，基底岩石提供了部分成矿物质。典型矿床的SPb同位素组成特征表明成矿物质具有混合来源的特征。

关键词: 川滇黔, 铅锌矿, 成矿物质来源, S同位素, Pb同位素

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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