中条山古元古代沉积岩容矿型铜钴矿床钴来源及富集过程  

Cobalt sources and enrichment processes of the Paleoproterozoicsedimentary rock-hosted Cu-Co deposits in the Zhongtiao Mountains

作　　者：邱正杰 范宏瑞[1,2] 杨奎锋 李麟瀚[1,2] QIU ZhengJie;FAN HongRui;YANG KuiFeng;LI LinHan(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]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 [2]中国科学院大学地球与行星科学学院,北京100049

出　　处：《岩石学报》2023年第4期1019-1029,共11页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(41902080、41890833);国家重点研发计划项目(2022YFC2903502)联合资助。

摘　　要：赋存在石墨片岩和大理岩内的山西中条山沉积岩容矿型铜钴矿床,其矿化类型为细脉浸染状和热液脉状,与中非铜矿带的钴矿床非常相似。本文以关键金属钴作为主要研究对象,综述了中条山矿集区钴矿成因研究近年来取得的重要进展。获得以下主要认识:(1)钴富集形成热液脉状矿化发生在造山抬升阶段,时间为~1.82Ga,而不是在沉积成岩阶段直接富集成矿;(2)黄铁矿原位Fe-S同位素揭示硫化有机质页岩是钴成矿的重要矿源层;(3)蒸发岩在造山作用过程中形成的高温、高盐、强氧化性流体是钴释放-迁移的关键介质;(4)热液白云石化导致流体pH升高和石墨片岩“褪色”反应导致流体氧逸度降低促进含钴硫化物的沉淀。基于上述认识,建立沉积-变质两阶段钴富集过程模型解释赋存在变沉积岩内的钴矿成因,它不同于经典的沉积岩容矿型层状铜钴矿床成矿模型。The sedimentary rock-hosted Cu-Co deposits in the Zhongtiao Mountains,Shanxi Province,are characterized by disseminated-veinlet to hydrothermal vein mineralization and hosted in the graphite schists and marbles.The geological setting is similar to the Co deposits in the Central African Copperbelt.This paper reviews the important progress on the cobalt ore genesis in the Zhongtiao region.The main conclusions are as follows:(1)cobalt enrichment in the hydrothermal vein mineralization occurred during the orogenic uplift stage at the time of~1.82Ga,rather than the sedimentary diagenetic stage;(2)in-situ pyrite Fe-S isotopes reveal that sulfidic shale is an important source rock for cobalt mineralization;(3)the high-temperature,high-salinity and strongly oxidizing fluid generated from the evaporite during the orogenic metamorphism is the key medium for the cobalt release and mobilization;(4)the increase of fluid pH caused by hydrothermal dolomitization and the decrease of fluid oxygen fugacity caused by the“fading”reaction of graphite schist facilitate the cobalt-bearing sulfide precipitation.Accordingly,a genetic model of two-stage cobalt enrichment induced by sedimentation and metamorphism is favored for the explanation on the genesis of cobalt ore hosted in meta-sedimentary rocks.This cobalt ore-forming model is different from the classical model of sediment-hosted stratiform Cu-Co deposits.

关 键 词：沉积岩容矿型铜钴矿床 造山变质作用 钴来源 钴富集 中条山地区 

分 类 号：P618.62[天文地球—矿床学]