胶东大尹格庄金矿床成矿流体组成  

Composition of ore-forming fluids in the Dayingezhuang gold deposit of the Jiaodong Peninsula,China

作　　者：刘育[1] 杨立强[1] 郭林楠[1] 李瑞红[1] 高帮飞 孟银生[1] 张瑞忠[1,3] 

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]中铁资源地质勘查有限公司,北京100039 [3]招金矿业股份有限公司,招远265400

出　　处：《岩石学报》2014年第9期2507-2517,共11页Acta Petrologica Sinica

基　　金：国家自然科学基金重点项目(41230311);国家科技支撑计划课题(2011BAB04B09);地质过程与矿产资源国家重点实验室开放课题(GPMR201307)联合资助

摘　　要：大尹格庄金矿床位于胶东半岛西北部招平断裂带中段,产于断裂带下盘绢英岩化带中。矿区内围岩蚀变发育,主要包括钾长石化、硅化、绢云母化、黄铁矿化、绿泥石化和碳酸盐化,其中硅化、绢云母化、黄铁矿化与金矿化密切相关。根据野外脉体穿插关系和矿物共生组合特点,大尹格庄金矿床金成矿作用从早到晚分为三个阶段：金-石英-黄铁矿阶段（早）、金（银）-石英-多金属硫化物阶段（中）、石英-方解石-黄铁矿阶段（晚）。矿石中石英的爆裂峰集中在330~510℃、240~330℃和160~240℃,分别对应成矿作用的早、中、晚三个阶段。成矿流体总体为中温,富CO2,含CH4、C2H6、H2S等挥发分的流体。NaCl-H2O-CO2图解及较高的C2H6含量,表明成矿流体主要来源于变质流体。各阶段成矿流体中气、液相组成相似,而含量规律性变化。早、中阶段成矿流体中N2含量较低,晚阶段升高,表明从早阶段到晚阶段流体系统逐渐开放,后期有大气降水的加入;从成矿早阶段到晚阶段,Cl-/SO2-4和Na＋/K＋升高,说明成矿流体从早阶段CO2-H2O-K2SO4型逐渐演化为中阶段和晚阶段CO2-H2O-NaCl型;Na＋、Cl-、K＋和SO2-4浓度逐渐降低,指示成矿流体从成矿早阶段到晚阶段盐度降低;H2O/CO2在晚阶段高于早、中阶段,指示流体有可能在中阶段发生了沸腾作用。成矿早阶段具有较高含量的H2S,表明金硫络合物可能是金的一种运移形式;流体类型的演变和沸腾作用可能是导致大尹各庄金矿床金沉淀的重要因素。The Dayingezhuang gold deposit, located in the central section of the Zhaoping Fault Zone, northwestern Jiaodong Peninsula, within the phyllic zone in the footwall of main fault. Wall-rock alteration is intense and has a variety of types that include potash feldspathization, silication, serieitization, pyritization, chloritization and carbonatation. Amongst these alterations, silication, sericitization and pyritization are considered more closely related with the gold mineralization. Based on the cutting relations of veins and paragenesis of ore minerals, we determined three major mineralization stages ： gold-quartz-pyrite, gold （silver） -quartz-polymetallic sulfides, quartz-calcite-pyrite. Employing the decrepitation thermometry to the ore quartz, we identified three concentrated ranges： 330 -510°C, 240 -330°C and 240 -330°C, which are corresponding with each of the mineralization stage above. The ore-forming fluids in the Dayingezhuang gold deposit are characterized by medium temperature and rich in CO2 content, contain a small amount of volatile gases, such as ca4 , C2H6 and H2S. The scheme of NaC1-H20-CO2 and the high level content of C2H6 existed in all of mineralization stages indicate that the ore-forming fluids mostly are the metamorphic water. Even though the gas-liquid content from different mineralization stages are similar with each other, we still observed certain rules along the ore-forming evolution. The trend of increasing N2 content indicates that the ore-forming fluids system switch to an open system in the late stage, and atmospheric water began to take part in the ore-forming fluids. The high quantity of H2S in the early gold mineralization indicates that the gold possibly was migrated as Au-S complex. The climbing ratios of C1-/SO4^2- and Na^＋/K ^＋ show that the ore-forming system convert from the CO2-H20-K2 SO4into CO2-H20-NaC1 system with the evolving process. The concentration of Na^＋ , C1^- , K^＋ and SO4^- decreased from early stage to later stage indicates that the sal

关 键 词：爆裂法测温 流体包裹体 气液相成分 大尹格庄金矿床 胶东 

分 类 号：P595[天文地球—地球化学] P618.51[天文地球—地质学]