胶东七里山金矿床载金矿物的矿物学特征和金赋存状态  

Mineralogical characteristics of gold-bearing minerals and occurrence state of gold in the Qilishan gold deposit in the Jiaodong Peninsula,Shandong Province,China

作　　者：曾庆文 马星华 张馨月[3] 舒启海 ZENG Qing-wen;MA Xing-hua;ZHANG Xin-yue;SHU Qi-hai(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 10083,China;College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]自然资源部成矿作用与资源评价重点实验室中国地质科学院矿产资源研究所,北京100037 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [3]成都理工大学地球科学学院,四川成都610059

出　　处：《矿物学报》2020年第6期714-722,共9页Acta Mineralogica Sinica

基　　金：国家重点研发计划项目(编号:2018YFC0603801);地质过程与矿产资源国家重点实验室开放课题(编号:GPMR201816);基本科研业务费项目(编号:KK1914,KK2013);国家自然科学基金国际(地区)合作与交流项目(编号:41911530106)。

摘　　要：七里山金矿床位于胶东灵北断裂带南西段,金品位较高且具有较好的找矿潜力。本文通过详细的镜下显微结构观察、电子探针和面扫描分析,对载金矿物的组成、成分及金的赋存状态进行了研究。结果表明,七里山金矿床主体为构造蚀变岩型矿化,局部发育石英脉型矿化,成矿作用可分为3期4个阶段,金属矿物主要发育自然金、银金矿、黄铁矿、黄铜矿和方铅矿等,脉石矿物主要是石英、绢云母和方解石。七里山矿床的金矿化主要发生在石英-黄铁矿阶段和石英-多金属硫化物阶段,金矿物(自然金、银金矿)主要以包裹金、裂隙/粒间金的形式赋存于黄铁矿和黄铜矿内部或矿物颗粒之间。电子探针显示石英-黄铁矿阶段发育成色一般的自然金(w(Au)=77.9%~78.9%)和银金矿,石英-多金属硫化物阶段发育成色更高的自然金(w(Au)>90.0%)和银金矿,暗示从成矿早阶段至中阶段随着成矿热液的演化,沉淀出的自然金纯度升高的过程。The Qilishan gold deposit is located in the southwestern section of the Lingbei fault zone in the Jiaodong Peninsula,Shandong Province.It has relatively high Au grade of ores and relatively good potential for further gold prospecting in depth.Based on the detailed microscopic observation of micrstextures,electron probe micro analysis(EPMA)and mapping,we have carried out this study on the mineralogical assemblage and composition of gold-bearing minerals and occurrence state of gold of the deposit.The Qilishan gold deposit has mainly altered-rock type of ores,with minor quartz-vein type of ores locally.Four stages of its mineralization have been identified.Main metallic minerals in this deposit are native gold,electrum,pyrite,chalcopyrite,and galena,etc.Gangue minerals are mainly quartz,sericite,and calcite.The mineralization of gold mainly occurred in the quartz-pyrite stage and quartz-polymetallic sulfide stage.Gold mainly occurred as inclusion and intergranular particle in or near the pyrite and chalcopyrite grains.EPMA analyses show that Au contents of the native gold particles formed in the quartz-polymetallic sulfide stage(w(Au)>90.0%)are apparently higher than those of gold particles formed in the quartz-pyrite stage(w(Au)=77.9%-78.9%),implying that the ore-forming fluid of the intermediate stage was more enriched in Au concentration than that of the early stage with the hydrothermal evolution.

关 键 词：金赋存状态 电子探针 七里山金矿床 胶东地区 

分 类 号：P618.51[天文地球—矿床学] P616.3[天文地球—地质学]