中缅毗邻区金腊Pb-Zn-Ag多金属矿田元素、稳定同位素和流体包裹体地球化学  

Geochemistry of Elements,Sulphur-Lead Isotopes and Fluid Inclusions from Jinla Pb-Zn-Ag Poly-Metallic Ore Field at the Joint Area across China and Myanmar Border

作　　者：陈永清[1] 黄静宁[1] 卢映祥 夏庆霖[3] 孙明祥 李建荣 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]云南省地质调查局,云南昆明650051 [3]中国地质大学资源学院,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2009年第4期585-594,共10页Earth Science-Journal of China University of Geosciences

基　　金：国家高技术研究发展计划"863"项目(No.2006AA06Z113);国家自然科学基金项目(No.40772197);国家科技支撑计划项目(No.2006BAB01A03)

摘　　要：跨越中缅边境的金腊铅-锌-银多金属矿田包括南腊和金厂两处铅锌银矿床,大地构造上处于保山-掸泰地块东缘,勐统-耿马-西盟元古宙-古生代被动大陆边缘活动带南段.通过对容矿围岩、与矿化有关的花岗岩和矿石元素地球化学以及矿石硫、铅同位素和流体包裹体的研究,结论如下:(1)与同类岩石相比,与矿化有关的花岗岩普遍富集Pb、Zn、Cu、Au、Sn、W等成矿元素,其中钾长花岗斑岩与Pb-Zn-Ag矿化关系最密切.(2)铅同位素表明,矽卡岩型致密块状矿石铅同位素比值(206Pb/204Pb、207Pb/204Pb和208Pb/204Pb)皆低于热液充填型角砾状矿石和似层状硅化白云岩型矿石,意味着形成于岩体接触带的矽卡岩型矿石相对形成于远离岩体的热液充填型角砾状矿石和似层状硅化白云岩型矿石含有更低的放射性成因铅.(3)铅-锌-银矿化主要经历了两个成矿期:矽卡岩化成矿期和中低温热液成矿期,前者主要形成铅-锌-铜(金)矿化,后者主要形成铅-锌-银矿化;中低温热液成矿期又可划分为两个成矿阶段:中温成矿阶段(200～290℃)和低温成矿阶段(140～200℃),前者主要形成交代充填型硅化角砾岩矿体,后者主要形成层间破碎带充填型硅化矿体.(4)金腊铅锌矿床、保山-镇康地块某些铅锌矿床和昌宁-孟连火山岩带的铅锌矿床,虽然产于不同的地质构造单元,但矿石铅同位素组成却具有类似的特征,而且矿化皆与喜马拉雅期侵位的花岗岩密切相关.这表明:虽然上述矿床产出于不同的地质构造单元,但成矿皆与喜马拉雅期构造岩浆活动具有某种内在联系.Jinla Pb-Zn-Ag poly-metallic ore field across China and Myanmar, located at the south segment of the Mengtong- Gengma-Ximeng passive continental margin of Proterozoic era-Palaeozoic era, the eastern margin of the Baoshan-Shantai Massif, includes the Nanla and the Jinchang Pb-Zn-Ag deposits. According to the studies on both the element geochemistry of the host rocks, the granites, and the ore deposits and the sulphur-lead isotopes as well as fluid inclusion from the ore deposits in Jinchang Pb-Zn-Ag deposits. The conclusions are drawn as follows. （1） The granites in this ore field are richer in Pb, Zn, Cu, Au, Sn, and W than in other granites, and the K-feldspar granite porphyry has a closer relationship with the mineralization. （2） The Pb isotope ratios （206Pb/204Pb, 207pb/204pb,2088pb/204pb） from the massive skarn Pb-Zn-Cu ores are lower than those from the brecciated Pb-Zn-Ag ores with quartzification and the stratiform Pb-Zn-Ag ores with chalcedonization, which may indicate that the former contains radioactive Pb less than the latter. （3） The Pb-Zn-Ag mineralizations may be divided into two ore-forming epochs： the skarn ore-forming epoch and the hydrotherma ore-forming epoch; the former is associated with Pb-Zn- Cu mineralization, the latter with Pb-Zn-Ag mineralization. The hydrothermal ore-forming epoch may be subdivided into two hydrothermal ore-forming stages： the mesothermal ore-forming stage （200-290℃） at which the brecciated ores were deposi- ted, and the epithermal ore-forming stage （140-200℃） at which the stratiform ores were formed. （4） The Jinla Pb-Zn-Ag deposits not only have the same features of Pb isotope ratios as some Pb-Zn deposits formed at the Baoshan-Zhengkang terrain and as some Pb-Zn deposits formed at the Changning-Menglian volcanic belt but also these Pb-Zn deposits are associated with the granites emplaced at Himalayan orogenic episode, which may indicate that although forming different geological tectonic terrains, these Pb-Zn deposits have intrinsi

关 键 词：铅-锌-银多金属矿化 地球化学 硫铅同位素 流体包裹体 中缅邻接区 

分 类 号：P618.41[天文地球—矿床学] P597[天文地球—地质学]