铅锌矿床中闪锌矿Cd含量及Zn/Cd值的地质意义  

Cd contents and Zn/Cd Ratios of Sphalerites and Their Geological Implications

作　　者：王光辉[1,2] 刘兵 匡爱兵[2] 

机构地区：[1]成都理工大学,四川成都610059 [2]四川省核工业地质调查院,四川成都610061 [3]新疆地矿局第一区域地质调查大队,新疆乌鲁木齐830013

出　　处：《西北地质》2016年第3期132-140,共9页Northwestern Geology

基　　金：基金项目:中国科学院地球化学研究所“Cd同位素对铅锌矿床的地球化学示踪研究---以川滇黔低温成矿域为例”(41503011)

摘　　要：以5个典型铅锌矿床为研究对象,测试了其闪锌矿中的Zn和Cd含量,发现同一标本上深色闪锌矿比晚期的浅色闪锌矿更富集Cd,其原因可能与流体中Zn/Cd值变化相关;而对比不同矿床不同颜色闪锌矿之间Cd的富集规律是没有意义的。同时,与岩浆作用相关的铅锌矿床,其闪锌矿中的Zn/Cd值与相关岩浆岩的Zn/Cd值相似,暗示闪锌矿中的Zn/Cd值可指示成矿物质来源。同时,川滇黔地区铅锌矿床显示出2组不同的Zn/Cd值：1高Zn/Cd值型（300~800）,以会泽矿床为代表,其Zn/Cd值介于峨眉山玄武岩和该区地层之间,暗示该类型矿床的成矿物质可能主要来源于峨眉山玄武岩和地层。2低Zn/Cd值型（20~70）,以富乐矿床为代表,其Zn/Cd值基本与地层相似,暗示该矿床的成矿物质可能主要来源于地层。而对比川滇黔地区铅锌矿床和与岩浆作用相关矿床的Cd含量及Zn/C值发现,成因不同的矿床,其Cd含量和Zn/Cd值具有较大差异。因此,铅锌矿床闪锌矿中的Cd含量及Zn/Cd值对于判别成矿物质来源和矿床成因具有指示意义。In this paper,the Zn and Cd contents in sphalerites from five typical Zn-Pb depositshave been investigated and tested.The results show that dark sphalerite（early stage）has higher Cd contents than light one（late stage）in a hand specimen,which may be caused by Zn/Cd decreasing of ore-forming fluids.Meanwhile,the sphalerites from magma-related Zn-Pb deposits have similar Zn/Cd ratios with the source bed,suggesting that Zn/Cd ratios could be a proxy to trace the origins of metallogenic materials.Zn/Cd ratios in sphalerite from major Zn-Pb deposits in Sichuan-Yunnan-Guizhou metallogenic province could be divided into two groups,which are：1High Zn/Cd ratios（e.g.the Huize deposit）,the deposits of this group have high Zn/Cd ratios（300-800）,which are varied between the ones of the Emeishan basalts（Zn/Cd ratios higherthan 1000）and sedimentary rocks（Zn/Cd ratios lower than 100）,suggesting that ore-forming metals were derived from the mixture of Emeishan basalts and strata;2Low Zn/Cd ratios（e.g.the Fule deposit）,the deposits of this group have low Zn/Cd ratios（20-70）,which are similar to that of sedimentary rocks,indicating that ore-forming metals were derived from the strata.Based on the Cd contents and Zn/Cd ratios,it＇s found that various ypes of Zn-Pb deposits have different Cd contents and Zn/Cd ratios.Therefore,the Cd content and the Zn/Cd ratio in sphalerite s are indicative in revealing the source of ore-forming materialsand genesis of Pb-Zn deposits.

关 键 词：Zn/Cd值 闪锌矿 铅锌矿床 成矿物质来源 矿床成因 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]