西藏边坝县白库铅锌银矿床地质地球化学特征及成因分析  

Geological and geochemical characteristics of Baiku Pb-Zn-Ag deposit in Bianba county,Tibet and analysis of its genesis

作　　者：高启荣 王东方 白志鸿 GAO Qirong;WANG Dongfang;BAI Zhihong(The Fourth Geological and Mineral Survey Institute of Henan Bureau of Geology and Mineral Exploration and Development,Zhengzhou 450003,China)

机构地区：[1]河南省地质矿产勘查开发局第四地质矿产调查院,郑州450003

出　　处：《地质找矿论丛》2023年第3期285-295,共11页Contributions to Geology and Mineral Resources Research

摘　　要：白库铅锌银矿床地处班公湖怒江缝合带南侧冈底斯念青唐古拉山弧盆系,古地理位置属比如盆地南缘。赋矿地层侏罗系中上统拉贡塘组(J_(23)l)浅海相碎屑沉积岩建造,其土壤地球化学特征及微量元素特征指示该地层为矿源层。硫同位素δ(^(34)S)值指示硫主要来源于生物成因硫化氢,少部分来源于蒸发岩和储存于盆地基底的海水硫酸盐。地下热卤水在白垩纪班公湖怒江弧后洋盆闭合碰撞作用下被活化,沿断裂运移过程中不断萃取地层中的金属元素形成成矿流体,成矿流体与生烃层的有机质发生一系列热化学还原反应,最终在构造有利部位的碳酸岩中富集成矿。综合区域地质背景、盆地构造演化史、矿床地球化学特征,白库铅锌银矿床属于MVT型铅锌银矿床。The Baiku Pb-Zn-Ag deposit is located in Gangdise-Nianqing Tangulashan arc basin system at southern side of Bangonghu-Nujiang suture belt.Palaeogeograpically it is located in the southern margin of Biru basin.The shallow marine sedimentary formation of Gongtang Formation(J_(23)l)of Middle-Upper Jurassic Series is the ore-bearing stratum that is indicated by characteristics of geochemistry and trace elements of soil above the stratum.Value ofδ(^(34)S)indicates that the sulfur is mainly derived from bio-genetic hydrogen sulfide and a small part from evaporate and sulfate in sea water at basement of the basin.During Cretaceous period collision of Bangonghu lake-Nujiang back arc basin closure activate brine underground and the brine moves along fractures and extracts metal elements to be formed as ore fluid.A series of chemical reduction take place between the ore fluid and organic matter in the hydrocarbon-generated layer and precipitate as ore with enrichment of metals in the fluid at favorable structural position of carbonate rocks.Integration of regional geological background,structural evolution history of the basin and geochemical characteristics of the deposit shows that Baiku Pb-Zn-Ag deposit belongs to MTV type Pb-Zn-Ag deposit.

关 键 词：矿床地质 地球化学 成矿流体 MVT型铅锌银矿床 比如盆地 西藏 

分 类 号：P618.52[天文地球—矿床学]