粤北曲仁盆地北缘凡口式MVT铅锌矿床的地球化学特征  

Geochemistry of Fankou-type MVT lead-zinc sulphide deposit in northern margin of Quren basin,Guangdong Province,China

作　　者：姚翠霞[1,2] 张术根[1,2] 王超[1,2] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,长沙410083 [2]中南大学地球科学与信息物理学院,长沙410083

出　　处：《中国有色金属学报》2013年第12期3518-3528,共11页The Chinese Journal of Nonferrous Metals

基　　金：国家"十一五"科技支撑计划项目(2009BAB43B00)

摘　　要：粤北曲仁碳酸盐岩盆地北缘聚集的铅锌硫化物矿床地质矿化特征相比于其他MVT矿床,具有成矿特殊性。为了确定该类矿床成矿流体和物质的来源以及成矿作用过程,对研究区矿床地层、断裂构造地球化学特征、稀土元素、硫铅同位素和流体包裹体特征进行系统研究。结果表明:地层、构造以及稀土元素研究结果显示该类铅锌硫化物矿床经历了黄铁矿矿化与铅锌矿化两个成矿作用过程,前者与赋矿层灰岩的物源联系更紧密,后者的成矿金属物质并非直接来自赋矿层灰岩,而是由通过北东、北西向断裂向上运移的盆地深部流体提供,且局部受到中基性岩浆侵入活动轻微改造;矿石及相关地质体同位素地球化学特征显示铅主要来自盆地基底碎屑岩层,部分来自盆地深部壳源重熔型花岗质岩浆,少部分来自盆地碳酸盐岩层,而硫主要为地层硫,小部分为壳源岩浆硫;闪锌矿流体包裹体气液相成分、盐度和温度结果显示铅锌热液成矿期古地热高异常,盆地基底碎屑岩含水系统及燕山期岩浆热液参与铅锌成矿。综合矿床地球化学特征可知,粤北曲仁盆地北缘凡口式MVT铅锌矿床属于两期热液叠加改造热液型铅锌矿床。Compared with other MVT deposits,the lead-zinc sulfide deposits gathering in the north margin of Quren carbonate basin,Guangdong Province,China,have mineralization particularity. The deposit strata and fault structure geochemistry,rare earth elements（REE）,sulphur isotope,lead isotope and fluid inclusion geochemistry were discussed for understanding the source of the ore-forming metal,fluids and the mineralization processes in Fankou-type lead-zinc deposit. The strata,fault structure and REE results show that this type deposit experiences pyrite and lead-zinc mineralization processes,the former gets closer provenance contact with limestone,while ore metal of the latter does not come directly from ore-hosting carbonate rocks,but gets from basin deep fluid transferred up by NE,NW faults,and is slightly modified by intermediate-basic magmatism. Lead and sulphur isotope geochemistry of ores and related geological samples shows that lead comes mainly from basement clastic formation,partly from crust remelting type granitic magma,little from carbonate rocks; sulphur is mainly from carbonate rocks,only a litter from crustal magma. Sphalerite fluid inclusions components,salinity and temperature results reveal that lead-zinc hydrothermal mineralization exists ancient geothermal anomaly,and basement clastic aquifer and Yanshanian granite are involved in lead-zinc mineralization. Fankou-type MVT lead-zinc deposit in this research area can be classified as two-hydrothermal superimposition-transformation lead-zinc deposit after geochemical characteristics of ore deposits being analyzed synthetically.

关 键 词：凡口式MVT铅锌矿床 地球化学特征 成矿流体 成矿物质来源 成矿作用过程 

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