湘西花垣矿集区柔先山铅锌矿床的成矿时间和物质来源
Geochronology and Ore-Forming Material Source Constraints for Rouxianshan Pb-Zn Deposit in Huayuan Ore Concentration Area, Western Hunan

花垣矿集区位于我国湘西-黔东成矿带，作为世界级的超大型铅锌矿床之一，预测储量超过千万吨，位于花垣矿集区中部渔塘矿田的柔先山铅锌矿床是区内典型铅锌矿床.采用闪锌矿Rb-Sr分相法获得了柔先山铅锌矿床的Rb-Sr等时线年龄为412±6 Ma(MSWD=1.5，初始86Sr/87Sr=0.709 32)，地质时代为早泥盆世，这一年龄限定了花垣地区铅锌矿床的时代.柔先山矿床的铅锌矿矿石流体包裹体、Sr-S-Pb同位素示踪研究显示，成矿流体可能是地层封存水与后期迁移流体的混合，成矿元素中的铅主要来源于围岩，硫由赋矿层位之上的含膏岩层经历热化学还原过程供给，铅和锶同位素特征都指示上地壳来源.
In Western Hunan-Western Hubei metallogenetic belt, the Huayuan ore concentration area with ten-million-tons expected reserves of Pb and Zn, is one of the world-class super-large Pb-Zn ore deposits. Rouxianshan Pb-Zn deposit located in the center of Huayuan area, is a typical deposit in the Yutang ore field. This study carries on Rb-Sr geochronology study of sphalerites from Rouxianshan, and utilizes phase-seperation method to achieve an ideal Rb-Sr isochron line, yielded an Early Devonian age of 412±6 Ma (MSWD=1.5, initial 86Sr/87Sr=0.709 32), which is meaningful for constraining the ore-forming age in Huayuan area. The fluid inclusions, Sr-S-Pb isotopic composition of ore samples from Rouxianshan have also been analyzed. The results indicate that the ore-forming fluid may have originated from a mixture of strata-sealed water and transporting fluid, and the ore are characterized by Pb-Sr isotopic composition from upper crust. Further, the Pb in ores mainly comes from the wall rocks, and the S attributed to the thermo-chemical sulfate reduction (TSR) of overlying gypsum-bearing rock formation