广西金秀寒武系黑色岩系中的热液脉状镍钴矿床超常富集规律与成矿条件  

The supernormal enrichment regularity and metallogenic conditions of hydrothermal vein-type nickel-cobalt ore deposit in the Cambrian black rock series of Jinxiu,Guangxi,South China

作　　者：张宝林[1,2,3] 王学海 苏艳平 沈晓丽[5] ZHANG Baolin;WANG Xuehai;SU Yanping;SHEN Xiaoli(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics/Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Ecology,Resources and Environment,Dezhou University,Dezhou 253023,Shandong,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,Shandong,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]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049 [4]德州学院生态与资源环境学院,山东德州253023 [5]山东科技大学地球科学与工程学院,山东青岛266590

出　　处：《地质通报》2023年第11期1793-1807,共15页Geological Bulletin of China

基　　金：科技部国家重点研发计划项目专题《热液型矿床钴成矿作用与找矿勘查》(编号2022YFC2903503);中国科学院地质与地球物理研究所自主创新项目《隐伏矿床定位预测理论与方法研究》(编号:31351460);山东省自然科学基金项目《下寒武统黑色页岩中Ni-Co多金属矿床沉淀-富集机制研究》(编号:ZR2020QD030);云南伟力达地球物理勘测有限公司科研项目《隐伏矿床预测与探查的新理论新技术应用研究》(编号:51650930);四川恒康矿业有限公司科研项目《目标矿区调查与评价研究》(编号:51741170)。

摘　　要：在华南地区的广西金秀寒武系黑色岩系中发现了热液脉状镍钴矿床,矿石品位超常富集,元素组合特殊,实属罕见,具有重要的科学价值和找矿意义。本文介绍龙华矿床的地质特征和矿石富集规律,以及矿物学和地球化学初步研究成果。含矿围岩是寒武系清溪组下段炭质泥岩,矿体可分为高品位热液脉状和低品位浸染状2类。主矿脉中出现镍-钴-砷和镍-钴-硫两类矿物组合,且两者呈分离状态,分别赋存在NWW向和NNW向断裂构造中。矿石成分主要是镍-钴砷化物、少量硫化物,以及石英和碳酸盐。采用电子探针方法分析了红砷镍矿、辉砷镍矿、硫镍矿、针镍矿、方钴矿、辉铋矿和自然铋矿物的元素含量,讨论了主要矿石矿物的Fe-Co-Ni三元图解。根据矿物内部结构构造和共生关系,厘清了矿物生成顺序,将矿石矿物的形成过程划分为内生热液作用期和表生作用期。元素面扫描分析结果表明,红砷镍矿内部Ni、Co、S元素具有显著的分带特征,可能是二次生长的结果。热液脉状镍钴矿床可能是加里东运动以前的古老地壳物质再循环的产物,花岗岩体与成矿作用的关系尚难评判,Ni-Co元素的超常富集可能主要来自于后期的构造-流体改造作用。A hydrothermal vein-type nickel-cobalt deposit was discovered in the Cambrian black rock series in Jinxiu,Guangxi,South China.The deposit is exceptionally rare and holds significant scientific and prospecting importance.This paper introduces the geological characteristics of the Longhua deposit,the rules governing ore enrichment,as well as mineralogical and geochemical investigations.The ore-bearing rock is carbonaceous mudstone in the lower part of the Cambrian Qingxi Formation,and the ore-bodies can be classified into two types:high-grade hydrothermal veins and low-grade disseminated types.Two main mineral assemblages are identified:Ni-Co-As and Ni-Co-S,occurring within the primary vein.Their distribution aligns with NWW and NNW trending faults,respectively.The primary ore minerals consist of Ni-Co arsenide,accompanied by a minor presence of sulfide,quartz and carbonate.Elemental contents of niccolite,gersdorffite,polydymite,millerite,skutterudite,bismuthite,and native bismuth minerals were analyzed using the electron probe method.Additionally,the Fe-Co-Ni ternary diagram of the primary ore minerals was examined.Based on the internal structure and paragenetic relationships of minerals,the sequence of mineral formation is elucidated,and the formation process of ore minerals can be divided into endogenic hydrothermal stage and epigenetic stage.The results of elemental mapping analysis reveal significant zonation characteristics in Ni,Co,and S elements within niccolite,possibly indicating secondary growth as the underlying cause.The hydrothermal vein-type nickel-cobalt deposit may be the product of the old crustal material recirculation before Caledonian Movement.The relationship between granites and mineralization is still difficult to judge.The supernormal enrichment of nickel-cobalt elements may mainly come from the late tectonic-fluid reformation.

关 键 词：黑色岩系 Ni-Co超常富集 热液脉状矿床 改造成矿 广西 

分 类 号：P618.62[天文地球—矿床学] P618.63[天文地球—地质学] P534.41