山西中条山宋家山钴铁矿床钴的赋存状态及成矿规律  

Cobalt occurrence and metallogenetic regularities of Songjiashan cobalt-iron deposit in Zhongtiaoshan of Shanxi Province

作　　者：李文[1,2] 张连昌[2] 谢尚君[2] 李文君 高炳宇[2] 张新[2] 董志国 王长乐 LI Wen;ZHANG LianChang;XIE ShangJun;LI WenJun;GAO BingYu;ZHANG Xin;DONG ZhiGuo;WANG ChangLe(College of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国科学院矿产资源研究重点实验室,中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》2024年第10期3114-3130,共17页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2022YFC2903502)资助.

摘　　要：宋家山钴铁矿床位于中条山地区东南缘“同善天窗”的中部,容矿岩石主要为古元古代宋家山群绛道沟组火山-沉积岩系。钴铁矿体受地层岩性控制,呈SN向层状展布。金属矿物主要为磁铁矿、黄铁矿、黄铜矿、硫铜钴矿和硫钴矿,非金属矿物主要为石英、方解石、绢云母和绿泥石。矿石构造以块状、似条带状、浸染状、团块状和细脉状为主。黄铁矿和黄铜矿多呈浸染状和细脉状分布。围岩蚀变主要包括硅化、绢云母化、黄铁矿化、碳酸盐化和绿泥石化等。钴铁矿体的形成主要包括沉积、变质和热液三个期次。矿石显微镜观察、硫化物扫描电镜和电子探针分析,表明钴元素主要赋存在硫铜钴矿、硫钴矿和黄铁矿中。黄铁矿特征元素Co/Ni比值主要集中在100~1000之间,个别比值小于100,反映硫化物的形成主体与热液活动有关。硫化物原位硫同位素组成δ^(34) S在12‰~16‰之间,低于元古代海水硫酸盐的δ^(34) S值(15‰~20‰),揭示热化学还原(TSR)在海水硫酸盐还原过程中起到关键作用。综合研究表明宋家山矿床富钴矿体的形成经历了初始火山-沉积、造山期间含钴变质流体沿片理构造充填交代、造山后期热液活动的叠加等过程。由此认为宋家山矿床成因类型属沉积-变质热液叠加型钴铁矿床。The Songjiashan cobalt-iron deposit is located in the central part of the“Tongshan skylight”on the southeastern edge of the Zhongtiaoshan area,and the ore-bearing rocks are mainly volcanic-sedimentary rock series of the Jiangdaogou Formation of the Paleoproterozoic Songjiashan Group.The cobalt-iron ore body is controlled by the lithology of the strata and is distributed in a SN strike.Metal minerals mainly include magnetite,pyrite,chalcopyrite,carrollite and linnaeite,while non-metallic minerals mainly include quartz,calcite,sericite and chlorite.The ore structures mainly comprise massive,banded,disseminated,bulk and veined.The pyrite and chalcopyrite were mostly distributed in disseminated and veined ores.The alteration of surrounding rocks mainly includes silicification,sericitization,pyritization,carbonation and chloritization.The formation of cobalt-iron ore bodies mainly includes three periods,namely,sedimentation,metamorphism and hydrothermal processes.Microscopic observation of ores,scanning electron microscopy and electron probe analysis of sulfides indicate that cobalt element is mainly hosted in carrollite,linnaeite and pyrite.The characteristic element Co/Ni ratio of pyrite is mostly between 100 and 1000,with several ratios less than 100,indicating that the formation of sulfides should be mainly related to hydrothermal processes.In-situ sulfur isotope composition of sulfidesδ^(34) S is between 12‰and 16‰,which is lower than those of the Proterozoic seawater sulfate(15‰~20‰).It can be seen that thermochemical sulfate reduction(TSR)plays an important role in the process of seawater sulfate reduction.Comprehensive research shows that the formation of cobalt-rich ore bodies in the Songjiashan deposit is attributed to the original volcanic-sediments,cobalt-containing metamorphic fluids filling and metasomatism along the foliation structure during the orogenic stage.In the late orogenic period,there was also a superposition of hydrothermal mineralization.Therefore,it is suggested that the geneti

关 键 词：钴的赋存状态 古元古代 沉积-变沉积岩型矿床 宋家山钴铁矿床 中条山地区 

分 类 号：P611[天文地球—矿床学] P618.62[天文地球—地质学]