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),(^(87)Sr/^(86)Sr)_(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CO_(2)、H_(2)O为主,个别还含有少量CH 4,液相成分以Na+、Ca^(2+)、Mg^(2+)、Cl^(-)为主,少量K^(+)、SO_(4)^(2-)。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(^(87)Sr/^(86)Sr)_(i)值高于赋矿围岩,与早寒武世海水的^(87)Sr/^(86)Sr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。
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(^(87)Sr/^(86)Sr)_(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 CO_(2)and H_(2)O,with minor CH 4 present in individual fluid inclusion,and the ionic compositions are dominated by Na^(+),Ca^(2+),Mg^(2+),Cl^(-)and minor K^(+)and SO_(4)^(2-).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(^(87)Sr/^(86)Sr)_(i)of sphalerite is higher than the wall rock,similar to the^(87)Sr/^(86)Sr 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.
作者
谢小峰
杨坤光
XIE Xiaofeng;YANG Kunguang(Faculty of Earth Sciences,China University of Geoscience,Wuhan 430074,Hubei,China;Geological Party 103,Guizhou Bureau of Geology&Mineral Exploration and Development,Tongren 554300,Guizhou,China;Technology Innovation Center of Mineral Resources Explorations in Bedrock,Ministry of Natural Resources,Guiyang 550004,Guizhou,China)
出处
《地质通报》
CAS
CSCD
北大核心
2021年第5期772-781,共10页
Geological Bulletin of China
基金
国家自然科学基金项目《黔东及其邻区早古生代构造变形及其对华南大陆再造的启示》(批准号:41472190)
中国地质调查局项目《贵州铜仁松桃锰矿矿集区矿产地质调查》(编号:DD20190166-17)
《贵州铜仁松桃锰矿矿集区矿产地质调查(大湾地区)》(编号:DD20190166-2020-09)
贵州省地质矿产勘查开发局地质科研专项项目《贵州松桃东部地区构造变形特征及其对铅锌矿的控制作用》(编号:黔地矿科合[2015]01号)
《黔东松桃地区南华纪锰矿成矿流体特征研究》(编号:黔地矿科合[2020]03号)。
作者简介
谢小峰(1986-),男,在读博士生,高级工程师,从事金属矿产地质勘查及研究工作。E-mail:jiansheng2865@126.com。
