内蒙狼山成矿带东升庙多金属硫化物矿床硫的来源及矿化过程  

Sulfur source and mineralization process of the Dongshengmiao polymetallic sulfide deposit in the Langshan ore belt,Inner Mongolia

作　　者：高兆富[1,2] 朱祥坤[1] 张衎[1] 罗照华[2] 包创[1,2] 唐超[1,2] 

机构地区：[1]中国地质科学院地质研究所、国土资源部同位素地质重点实验室、大陆构造与动力学国家重点实验室,北京100037 [2]中国地质大学地球科学与资源学院,北京100083

出　　处：《岩石学报》2015年第12期3725-3731,共7页Acta Petrologica Sinica

基　　金：国土资源部地质调查项目(12120113015700)资助

摘　　要：东升庙多金属硫化物矿床是狼山成矿带最大和最典型的铅锌多金属硫化物矿床,目前该矿床硫的来源及成矿过程仍存在争议。本文对矿区常见硫化物矿石和最重要的赋矿围岩——绢云石墨片岩中的硫化物分别进行硫同位素分析。结果显示东升庙矿床的硫化物普遍富集硫的重同位素,且矿石与围岩中的硫化物的硫同位素分布范围均较为集中。绢云石墨片岩中的黄铁矿的δ^(34)S值在+19.4‰^+23.4‰之间,具有和当时海水硫酸盐相似的硫同位素组成,指示围岩中的不规则黄铁矿是孔隙水(海水)中的硫酸盐被完全还原后形成的。矿石硫化物的δ^(34)S值在+28.3‰^+31.3‰之间,相比围岩中的黄铁矿明显富集硫的重同位素,指示两者具有不同的硫源。矿石中的硫可能源自基底地层中蒸发岩的溶解,由此形成的硫酸盐占主导的热液流体可萃取大量铅、锌等金属,当遇到狼山群地层中富含有机质的沉积岩时发生热化学还原反应,从而造成硫化物的大量卸载,形成金属硫化物矿床。The Dongshengmiao polymetallic sulfide deposit is the largest and the most representative Zn-Pb deposit in the Langshan area,however,its sulfur source and mineralization process are still controversial. Here the sulfur isotopic compositions of sulfides from both sulfide ores and the most common wall rock,graphite-rich mica schists are compared. The δ^（34）S results of pyrites from graphite-rich mica schists vary from 19.4‰ to 23.4‰ which are similar with coeval seawater sulfates,indicating complete sulfate reduction of pore seawater to pyrite; whereas sulfides from the ores show heavier S isotope compositions with δ^（34）S values ranging from 28.3‰ to 31.3‰,indicating their different sulfur sources and mineralization processes. The sulfur of ores may be derived from evaporates in old basement and the resulting sulfate-dominated hydrothermal fluids can extract large amounts of metals,like Zn,Pb etc. When they met the organic-rich rocks in the Langshan Group,thermochemical reduction could occur and sulfide ores were then formed.

关 键 词：硫同位素 硫的来源 矿化过程 东升庙矿床 狼山成矿带 

分 类 号：P595[天文地球—地球化学]