谢小峰, 杨坤光. 2021: 黔东盘石—盘信地区铅锌矿床Rb-Sr等时线年龄与流体包裹体特征及其找矿意义. 地质通报, 40(5): 772-781.
    引用本文: 谢小峰, 杨坤光. 2021: 黔东盘石—盘信地区铅锌矿床Rb-Sr等时线年龄与流体包裹体特征及其找矿意义. 地质通报, 40(5): 772-781.
    XIE Xiaofeng, YANG Kunguang. 2021: Rb-Sr Isotope ages and fluid inclusion characteristics of Pb-Zn deposit and their prospecting significance in Panshi-Panxin region, eastern Guizhou Province. Geological Bulletin of China, 40(5): 772-781.
    Citation: XIE Xiaofeng, YANG Kunguang. 2021: Rb-Sr Isotope ages and fluid inclusion characteristics of Pb-Zn deposit and their prospecting significance in Panshi-Panxin region, eastern Guizhou Province. Geological Bulletin of China, 40(5): 772-781.

    黔东盘石—盘信地区铅锌矿床Rb-Sr等时线年龄与流体包裹体特征及其找矿意义

    Rb-Sr Isotope ages and fluid inclusion characteristics of Pb-Zn deposit and their prospecting significance in Panshi-Panxin region, eastern Guizhou Province

    • 摘要: 黔东盘石—盘信地区铅锌矿床位于雪峰山西缘,扬子地块与江南造山带的结合部位,是黔东地区比较典型的铅锌矿床。对该区铅锌矿床成矿期闪锌矿进行Rb-Sr等时线法定年,获得成矿年龄为486±3 Ma(MSWD=1.2),(87Sr/86Sr)i值为0.70918±0.00002。成矿期方解石的流体包裹体岩相学、显微测温及成分分析表明,该区流体包裹体以富液的气液两相包裹体为主,均一温度为277℃,包裹体气相成分以CO2、H2O为主,个别还含有少量CH4,液相成分以Na+、Ca2+、Mg2+、Cl-为主,少量K+、SO42-。综合研究表明:本区矿床形成于晚寒武世末—早奥陶世初,晚于赋矿地层寒武系第二统清虚洞组,属于后生成矿。闪锌矿(87Sr/86Sr)i值高于赋矿围岩,与早寒武世海水的87Sr/86Sr值相近,结合区域地层含矿性分析,推测成矿物质可能来源于下伏寒武系牛蹄塘组黑色岩系;成矿流体为中低温热卤水成因,可能还混有其他热液来源,Pb、Zn元素在成矿流体中以氯化物形式迁移的可能性较大。

       

      Abstract: The Pb-Zn deposit in Panshi-Panxin area, located on the Western margin of Xuefeng Mountain and the junction of Yangtze block and Jiangnan orogenic belt, is relatively a typical one in Songtao area, East Guizhou.The Rb-Sr isochronal dating on sphalerite of main metallogenic period yields an age of 486±3 Ma(MSWD=1.2) and (87Sr/86Sr)i=0.70918±0.00002.The results of petrography, microthermometer and composition analysis on fluid inclusion in calcite show that the liquid-rich liquid-vapor-type fluid inclusions are the primary ones with a homogenization temperature of 277.23℃, and vapor phases are dominated by CO2 and H2O, with minor CH4 present in individual fluid inclusion, and the ionic compositions are dominated by Na+, Ca2+, Mg2+, Cl- and minor K+and SO42-.The comprehensive studies show that the Pb-Zn deposit of this area was formed in the Late Cambrian to Early Ordovician, later than the country rock of Cambrian Second Series Qingxudong Formation, and indicate a genesis of epigenetic deposit.The(87Sr/86Sr)i of sphalerite is higher than the wall rock, similar to the 87Sr/86Sr ratio of Early Cambrian seawater.Based on the analysis of the ore-bearing potential of the regional strata, it is speculated that the metallogenic material is derived from the Cambrian Niutitang Formation black shale series.The ore-forming fluid is of medium and low temperature hot brine origin and may be mixed with other hydrothermal sources.It is more likely that Pb and Zn migrated in the ore-forming fluid in the form of chloride.

       

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