胶东大尹格庄金矿床成矿流体特征与演化  

Characteristics and evolution of ore-fluids of the Dayingezhuang gold deposit,Jiaodong gold province

作　　者：魏瑜吉 邱昆峰[1] 郭林楠[1,2] 刘向东 汤磊[4] 史启发 高学坎 WEI YuJi;QIU KunFeng;GUO LinNan;LIU XiangDong;TANG Lei;SHI QiFa;GAO XueKan(State Key Laboratory of Geological Process and Mineral Resources,China University of Geosciences,Beijing 100083,China;Chengdu Center,China Geological Survey,Chengdu 610081,China;No.6 Exploration Institute of Geology and Mineral Resources of Shandong Province,Weihai 264209,China;Zhaoyuan Gold Mining Limited Company Dayingezhuang Gold Deposit,Zhaoyuan 265413,China)

机构地区：[1]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 [2]中国地质调查局成都地质调查中心,成都610081 [3]山东省第六地质矿产勘查院,威海264209 [4]招金矿业股份有限公司大尹格庄金矿,招远265413

出　　处：《岩石学报》2020年第6期1821-1832,共12页Acta Petrologica Sinica

基　　金：国家重点研发计划(2019YFA0708603、2016YFC0600107-4);国家自然科学基金项目(41230311、41572069);高等学校学科创新引智计划(BP0719021)联合资助。

摘　　要：胶东是我国最重要的黄金产地,也是全球成矿晚于赋矿围岩近2Ga的巨型金矿集区之一。大尹格庄金矿床位于胶西北招平断裂中段,是区域内典型的超大型蚀变岩型金矿床,也是胶东金矿集区内最大的金银伴生矿床。本研究在详实的野外地质调查和岩相学观察基础上,对不同成矿阶段的石英中流体包裹体进行碳、氢、氧同位素测试和计算。大尹格庄金矿床热液成矿过程可分为四个阶段:黄铁矿-绢云母-石英阶段(Ⅰ阶段)、石英-黄铁矿阶段(Ⅱ阶段)、石英-多金属硫化物阶段(Ⅲ阶段)和石英-方解石-黄铁矿阶段(Ⅳ)。氢-氧同位素组成表明,Ⅰ阶段流体的δD为-84.4‰^-68.4‰,δ18O为2.04‰~7.36‰;Ⅱ阶段流体的δD为-78.6‰^-69.8‰,δ18O为-0.3‰~4.2‰;Ⅲ阶段流体的δD为-81.4‰^-72.0‰,δ18O为-3.47‰^-1.25‰。随着成矿作用进行,δ18O逐渐降低。流体包裹体的碳-氧同位素分析表明,δ13C和δ18O分别随成矿作用的进行降低和升高。两种测试获得的氧同位素变化趋势不同,可能是由于前者是通过石英单矿物氧同位素计算得到的流体包裹体中水的氧同位素,而后者测定的是流体包裹体中CO2的氧同位素。综合分析表明,大尹格庄金矿床成矿流体主体为变质水;成矿作用过程中,断裂带强烈构造变形诱发次生包裹体的形成导致氢氧同位素组成向中生代大气水漂移。The Jiaodong gold province,defined as the largest gold province in China,postdates^2Ga years of host rock.The Dayinggezhuang gold deposit,located in the middle section of the Zhao-Ping fault,is a world-class gold deposit characterized by disseminated and stockwork style mineralization.Four stages of ore-forming processes were identified,namely sericite-quartz-pyrite stage(stageⅠ),quartz-pyrite stage(stageⅡ),quartz-pyrite-sphalerite-galena stage(stageⅢ),and quartz-calcite-pyrite stage(stageⅣ).In stageⅠ,theδD range from-84.4‰to-68.4‰and theδ18O range from 2.04‰to 7.36‰.In stageⅡ,theδD range from-78.6‰to-69.8‰and theδ18O range from-0.3‰to 4.2‰.In stageⅢ,theδD range from-72.0‰to-81.4‰and theδ18O range from-3.47‰to-1.25‰.Theδ18O values decreased with the mineralization going on.In contrast,theδ13C andδ18O were decreased and increased respectively,which is distinct from theδ18O of H-O isotope composition.The probable reason is that the test object of H-O isotopes composition is the water in inclusions but the object of C-O isotopes is the CO2 in inclusions.Metamorphic water was the dominant origin of ore-fluid of Dayingezhuang gold deposit.The secondary inclusions caused by continuous structural deformation may give rise to the change of isotopes composition.

关 键 词：C-H-O同位素 成矿流体演化 大尹格庄金矿床 胶东金矿集区 

分 类 号：P597.2[天文地球—地球化学] P618.51[天文地球—地质学]