ZHANG Hai1, MENG Chang-zhong1, QI You-qiang2, TANG Yong-yong2, JIN Xiang-lin1, CHEN Xing1, LENG Cheng-biao2
(1. Guizhou Province Bureau of Geology and Mineral Resources, No.113 Geological Brigade, Liupanshui 553001, China;
2. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China)
Abstract: The Sichuan-Yunnan-Guizhou Pb-Zn metallogenic domain, located on the southwest margin of Yangtze craton, is one of most important lead-zinc mineralization belts in China. However, there is still a strong debate on the source of ore-forming materials. In this paper, we focus on the Yunluheba Pb-Zn ore field (including Haoxing, Shunda, Fuqiang and Shizdong Pb-Zn deposits) in the northwest of Guizhou Province, which has not been well studied until now, and try to determine the source of ore-forming materials by analysing the sulphur and lead isotopic compositions for different sulfides. The analytical results of sulphur isotopes show that most sulphides from the Haoxing mining area have a narrow δ34S range (-1.5‰–2.7‰), suggesting that sulphur mainly originated from the mantle. Moreover, one pyrite sample has a very low δ34S value (i.e. -18.1‰), which could have resulted from the reduction of bacterial sulphur. Lead isotope data show that different types of ore from different deposits all has uniform Pb isotopic composition, i.e. 206Pb/204Pb = 18.196–18.525, 207Pb/204Pb = 15.645–15.731, and 208Pb/204Pb = 38.415–39.058, respectively. Furthermore, the oxidized ores generally have similar Pb isotopes with those of sulphide ores, which indicates that later oxidation leaching action did not cause lead isotope fractionation. Based on a comparison of the Pb isotopic data for different strata and deposits from Yunluheba and its adjacent regions, we proposed that the lead metal could be mainly derived from the basement rocks, rather than the wall rocks and/or Permian basalts.
Keywords: Pb-Zn deposit; sulphur isotope; lead isotope; Yunluheba; Guizhou Province
Email: zhanghai01504130@163.com
ACTA MINERALOGICA SINICA Vol. 36, No. 2, 2016, Page 271-276
