刚果(金)Luiswishi铜钴矿床流体包裹体特征与成矿机制  

Fluid inclusions cracteristics and mineralization mechanism of the Luiswishi copper-cobalt deposit in the Democratic Republic of Congo

作　　者：曾瑞垠 祝新友 王蓉[1] 朱政坤 蒋斌斌 张雄 孙宁 郑长友 岳鹏军 ZENG Rui-yin;ZHU Xin-you;WANG Rong;ZHU Zheng-kun;JIANG Bin-bin;ZHANG Xiong;SUN Ning;ZHEN Chang-you;YUE Peng-jun(Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China;Sinotech Minerals Exploration Co.,Ltd.,Bejing 100012,China;Sino-Zijin Resources Ltd.,Bejing 100012,China;Yunnan Metallurgical Resources,Kunming 650093,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]中色地科矿产勘查股份有限公司,北京100012 [3]中色紫金地质勘查(北京)有限责任公司,北京100012 [4]云南冶金资源股份有限公司,云南昆明650093

出　　处：《矿物学报》2022年第6期719-731,共13页Acta Mineralogica Sinica

基　　金：国家重点研发计划“深地资源勘查开采”重点专项项目所属课题(编号:2017YFC0602403);刚果(金)PE527铜钴矿权矿产勘查项目(编号:ZJHY-CDM-PE527-201801)。

摘　　要：刚果(金)Luiswishi铜钴矿床位于加丹加铜钴成矿带中,属于沉积岩容矿层状铜钴矿床,主要发育顺层的层状矿脉和穿层的高角度矿脉。本文通过对2种矿脉的流体包裹体岩相学观察、显微测温和激光拉曼成分分析发现,2种矿脉均存在气液两相包裹体和含子晶三相包裹体等2类,气液两相包裹体中存在一套深色包裹体。含子晶三相包裹体含丰富的盐类及硬石膏子晶,代表了氧化性含矿卤水,具中高温(200~360℃)、高盐度(33%~49%)的特征。高角度矿脉的均一温度和盐度略高于层状矿脉,均属于Na^(+)、K^(+)、Ca^(2+)-Cl^(-)、SO_(4)^(2-)型盆地卤水,主要来源于海相蒸发岩的溶解。深色气液两相包裹体代表了还原性流体,具有中高温(200~360℃)中低盐度(16%~23%)的特征,来源于碳质页岩和沉积物中藻类生物分解。氧化性含矿卤水通过断裂构造迁移至流体封闭的还原环境中,向两侧渗透率较高的砂质白云岩和碎屑岩侧向流动,与还原性流体、含有机质地层发生氧化还原反应,形成矿山组多层位的层控铜钴矿体,成矿机制为盆地卤水交代成矿。The Luiswishi copper-cobalt deposit is located in the Katanga copper-cobalt metallogenic belt.It belongs to the sediment-hosted stratiform copper-cobalt deposit.There are mainly stratified veins along the bed and high angle veins cutting the bed.The fluid inclusions in minerals from two types of ore veins have been petrographically observed and then analyzed by means of microthermometry and Laser Raman spectrometry in this paper.The results show that two types of fluid inclusions,which are daughter mineral-bearing three-phase inclusions and vapor-liquid two-phase inclusions,have been identified in minerals of two types of ore veins.There is a set of dark inclusions within the type of vapor-liquid two-phase inclusions.The daughter mineral-bearing three-phase fluid inclusions are rich in daughter mineral of halite,sylvite,and anhydrite.Their contained fluid represents oxidized ore-bearing brine which is characterized with medium-high temperatures(200-360℃),and middle-high salinities(33%-49%).Homogenization temperatures and salinities of fluid inclusions in minerals of high angle veins are slightly higher than those of stratified veins.All fluids in three-phase inclusions belong to the Na^(+),K^(+),Ca^(2+)-Cl^(-),SO_(4)^(2-)type of basinal brine which was sourced from the dissolution of marine evaporate.The dark two-phase inclusions,in which the fluid represents reduced fluid,are characterized with medium to low salinities(16%-23%)and medium to high homogenization temperatures(200-360℃).The reduced fluid was derived from the biodegradation of algae in carbonaceous shale and sediments.It is believed that the oxidized ore-forming brine firstly migrated through the fracture structure into the fluid-enclosed reducing environment,then laterally penetrated into relatively high permeable sandy dolomite and clastic rocks in two sides of the fluid channel,and thirdly reacted with the reduced fluid and organic-rich strata in form of the oxidation-reduction reaction which had resulted in the formation of the multi-layered

关 键 词：流体包裹体 含矿卤水 还原性流体 成矿机制 流体混合 氧化还原反应 Luiswishi铜钴矿床 

分 类 号：P618.41[天文地球—矿床学]