黔东南丹寨地区热液脉型铅锌矿床成矿流体性质及来源  

Properties and Origins of the Ore-Forming Fluids of Hydrothermal Vein-Type Pb-Zn Deposits in the Danzhai area in the Southeastern Guizhou,China

作　　者：邓浩铭 唐永永[1] 叶霖[1] 王新松[1] DENG Haoming;TANG Yongyong;YE Lin;WANG Xinsong(State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang Guizhou 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550081 [2]中国科学院大学,北京100049

出　　处：《矿物学报》2025年第1期39-54,共16页Acta Mineralogica Sinica

基　　金：贵州省地质勘查资金项目(编号:2024-2);贵州省省级科技计划项目(批准号:黔科合基础-ZK[2021]重点047)。

摘　　要：湘西−黔东地区是我国重要的铅锌资源战略接续区。近年来,该区找矿勘查成果显著,新发现多个热液脉型铅锌矿床,成矿特征显著区别于区内广泛发育的MVT型铅锌矿床。这些矿床呈NE-SW向展布,Pb+Zn品位高(~10%),赋存于前寒武系浅变质碎屑岩中,发育强烈的硅化,还伴生有大量的Ga、Ge、In、Cd、Ag、Sb等关键金属,矿体规模较大(如老东寨单矿体可达中型),具有良好的找矿潜力。前人已开展较多研究取得了重要进展,但对成矿流体性质和来源的认识仍存在较大争议。本文以丹寨地区的老东寨、乌寿、新华脉型铅锌矿床为研究对象,在系统的岩、矿相学研究基础上,识别出两期热液成矿事件。早期热液成矿以发育深色(褐色-棕褐色)粗粒闪锌矿为特征,晚期则以发育浅色(米黄色)闪锌矿和大量方铅矿化为显著特征。通过开展不同成矿期石英中流体包裹体测温和H-O同位素分析,结果显示,早期石英流体包裹体的均一温度分布于160~266℃(平均214℃),盐度为4.5%~10.5%NaCl equiv(平均6.6%NaCl equiv);晚期石英流体包裹体的均一温度分布于115~222℃(平均171℃),盐度为5.7%~13.8%NaCl equiv(平均10.0%NaCl equiv)。成矿早期石英流体包裹体δD_(SMOW)值为–66‰~–49‰,δ^(18)O H_(2)O值为1.5‰~4.7‰;晚期石英流体包裹体δD_(SMOW)值为–65‰~–52‰,δ^(18)O H_(2)O值为–3.9‰~1.8‰。在δ^(18)O H_(2)O-δD_(SMOW)图中,早期石英流体包裹体样品落在靠近变质水区域,晚期样品向大气降水线偏移。综合分析认为,丹寨地区热液脉型铅锌多金属矿床经历了至少两期热液叠加成矿事件,早期成矿流体主要来源于造山带变质流体,晚期成矿流体为造山带变质流体和盆地卤水的混合。The Western Hunan and Eastern Guizhou district is an important strategic reserve area of Pb-Zn resources in China.Recently,remarkable achievements have been made in mineral prospecting and exploration in this area.A number of hydrothermal vein type Pb-Zn deposits have been discovered.Their metallogenic characteristics are significantly different from those of the MVT Pb-Zn deposits mainly occurred in carbonate strata in the region.They are characterized with the NE-SW distribution,high Pb+Zn grades(~10%),host of Precambrian low-grade metamorphic rocks,extensive silicification,association of a large number of key metal elements(Ga,Ge,In,Cd,Ag,Sb,etc.),and relatively large ore bodies(such as a single ore body of the Laodongzhai deposit has medium sized metal reserve).Thus,there is great prospecting potential of Pb-Zn resources in the area.Many studies have been carried out by predecessors and important progresses have been made.However,the understandings of properties and sources of their ore-forming fluids are still controversial.In this paper,based on the systematic petrographical and mineralogical studies of samples of the Laodongzhai,Wushou and Xinhua vein-type Pb-Zn deposits in Danzhai area,two stages of hydrothermal mineralization events have been identified.The early hydrothermal mineralization is characterized with dark colored(brown to brownish black)coarse-grained sphalerites,while the late hydrothermal mineralization is characterized with the light colored(beige)sphalerites associated with lots of galena.Fluid inclusion measurement and H-O isotope analysis were carried out for quartzs of different ore-forming stages.The results show that the homogenization temperatures and salinities of fluid inclusions in quartzs of the early mineralization stage vary from 160℃to 266℃(average of 214℃)and from 4.5%NaCl equiv to 10.5%NaCl equiv(average of 6.6%NaCl equiv),respectively.The homogenization temperatures and salinities of fluid inclusions in quartzs of the late stage are 115-222℃(average of 171℃)and 5

关 键 词：脉型铅锌矿 黔东南 H-O同位素 流体包裹体 老东寨 

分 类 号：P618[天文地球—矿床学] P597[天文地球—地质学]