内蒙古扎拉格阿木铜矿成矿流体与成矿机制  

Research on metallogenic fluids and metallogenic mechanism of the Zhalageamu copper deposit,Inner Mongolia

作　　者：车东 王建平[2] 吴起鑫 张照志[1] 邢恩袁[1] 沈存利 杨文海 郭海蛟 CHE Dong;WANG Jianping;WU Qixin;ZHANG Zhaozhi;XING Enyuan;SHEN Cunli;YANG Wenhai;GUO Haijiao(Institute of Mineral Resources,CAGS,MNR Key Laboratory of Metallogeny and Mineral Assessment China,Beijing 100037,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),State Key Laboratory of Geological Processes and Mineral Resources,Beijing 100083,China;Nonferrous Geological Erploration Bureau of Inner Mongolia,Hohhot,Inner Mongolia O10010,China)

机构地区：[1]中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室,北京100037 [2]中国地质大学(北京)地球科学与资源学院地质过程与矿产资源国家重点实验室,北京100083 [3]内蒙古自治区有色地质勘查局,内蒙古呼和浩特010010

出　　处：《地质学报》2023年第8期2575-2592,共18页Acta Geologica Sinica

基　　金：内蒙古自然资源厅院士项目(编号2022-TZH03);内蒙古自治区地质勘查基金(编号2018-01-YS01)联合资助的成果。

摘　　要：扎拉格阿木铜矿床位于锡林浩特地块北缘,矿体赋存于二叠系砂质板岩和角砾岩中,受NE向断裂控制,为中温热液脉型铜矿床。本文通过流体包裹体和C-H-O-S-Pb同位素地球化学研究手段,来探讨扎拉格阿木铜矿成矿机制。成矿热液期存在5个成矿阶段:钾长石阶段、石英-绢云母阶段、石英-黄铁矿阶段、石英-多金属硫化物阶段、石英-方解石阶段。其中石英-多金属硫化物阶段为主成矿阶段,本阶段主要发育富液相、富气相、含子矿物包裹体。富液相包裹体均一温度与盐度分别为:138~289℃和2.06%~16.11%NaCleq;含子矿物包裹体均一温度与盐度分别为:320~374℃和32.68%~39.81%NaCleq,包裹体气体成分除少量CO_(2)以外,均为H2O。H-O同位素分析得出,石英中的δO18值为-8.5‰~6.5‰,流体的δD值为-116‰~-98‰,暗示早阶段成矿流体主要为岩浆热液,晚阶段伴有大气降水混入。C-O同位素分析表明,δ^(13)C值为-10.1‰~-6.9‰,δ^(18)OSMOW介于2.5‰~11.7‰,在δ^(18)O-δ^(13)C图上数据点落在岩浆水与大气水的中间区域。矿石硫化物δ34S值介于-4.5‰~1.5‰,指示具有幔源岩浆硫的特征。矿石硫化物Pb同位素^(208)Pb/^(204)Pb、^(207)Pb/^(204)Pb和^(206)Pb/^(204)Pb比值分别为38.034~38.609、15.497~15.655和18.141~18.446,推测Pb具有地幔来源的特点并伴有地壳或造山带Pb混入。成矿过程中伴随着流体沸腾作用,成矿物质沉淀受早期形成的岩浆热液与后加入大气降水混合的影响。The Zhalageamu copper deposit is located on the north margin of the Xilinhot Block.As a mesothermal hydrothermal vein copper deposit,the ore bodies are hosted in the Permian sandy slate and breccia and controlled by NE trending faults.In this paper,the metallogenic mechanism of the Zhalageamu copper deposit is discussed by means of fluid inclusions and C-H-O-S-Pb isotopic geochemical methods.There are five metallogenic stages in the ore-forming hydrothermal period:potassium stage,quartz-sericite stage,quartz-pyrite stage,quartz-polymetallic sulfide stage,quartz-calcite stage.Among them,the quartz-polymetallic sulfide stage is the main ore-forming stage,and mainly develops liquid-rich,gas-rich,and mineral-bearing inclusions.The homogenization temperatures and salinities of liquid-rich inclusions range from 138℃to 289℃,and 2.06%NaCleq to 16.11%NaCleq,respectively.The homogenization temperatures and salinities of mineral-bearing inclusions range from 320℃to 374℃and 32.68%NaCl eq to 39.81%NaCleq,respectively.The gases in inclusions are mainly composed of H2O with small amount of CO_(2).The H-O isotopic analysis shows that theδ^(18)O of quartz varies from 8.5‰to 6.5‰,and theδD of the fluid varies from 116‰to 98‰,which indicates that the ore-forming fluids in the early stage are mainly magmatic hydrothermal fluids with meteoric water mixed in the late period.The C-O isotopic analysis shows that theδ^(13)C from 10.1‰to 6.9‰,and theδD of the fluid varies from 2.5‰to 11.7‰,are plotted in the zone between magmatic water and meteoric water in theδ^(18)O-δ^(13)C diagram.Theδ34S of the ore sulfides ranges from 4.5‰to 1.5‰,indicating the characteristics of mantle-derived magmatic sulfur.^(208)Pb/^(204)Pb,^(207)Pb/^(204)Pb and ^(206)Pb/^(204)Pb ratios of ore sulfides are 38.034 to 38.609,15.497 to 15.655,and 18.141 to 18.446,indicating the characteristics of mantle origin and is accompanied by the mixing of Pb in the crust or orogen.The mineralization process is accompanied by fluid boiling,an

关 键 词：流体包裹体 C-H-O-S-Pb同位素 热液脉型铜矿 内蒙古扎拉格阿木铜矿 

分 类 号：P618.41[天文地球—矿床学]