皖东钱台子金矿床成因:流体包裹体及氢氧同位素约束  

Genesis of Qiantaizi Au deposit in the east Anhui province,China:constraints of fluid inclusion and H,O isotopic data

作　　者：宗雯[1] 康丛轩[2,3] 杨献忠 蔡逸涛[2] ZONG Wen;KANG Congxuan;YANG Xianzhong;CAI Yitao(Geological Survey of Jiangsu Province, Nanjing 210018, China;Nanjing Center of Geological Survey, CGS, Nanjing 210016, China;School of Earth Sciences and Engineering, Hehai University, Nanjing 211100, China)

机构地区：[1]江苏省地质调查研究院,南京210018 [2]中国地质调查局南京地质调查中心,南京210016 [3]河海大学地球科学与工程学院,南京211100

出　　处：《地质找矿论丛》2022年第2期164-173,共10页Contributions to Geology and Mineral Resources Research

基　　金：安徽省公益性地质调查基金项目(编号:2014K5)资助。

摘　　要：钱台子金矿床是一个产于皖东蚌埠隆起区东端的石英脉型小型矿床,矿体主要赋存于变质结晶基底五河岩群中,受张扭性断裂控制。本文通过对不同阶段石英进行系统的包裹体岩相学观察、显微测温、激光拉曼探针及氢氧同位素分析,探讨了该矿床的流体来源及矿床成因。结果表明,钱台子金矿床流体包裹体有纯CO_(2)型、CO_(2)—H_(2)O型和H_(2)O—NaCl型3种,包裹体均一温度集中在286~385℃,w(NaCl,eqv)=4.80%~12.56%,平均8.29%;不同阶段石英的δ^(18)O_(V-SMOW)变化范围为9.0×10^(-3)~15.2×10^(-3),对应的δ^(18)O_(水)变化范围为2.12×10^(-3)~9.70×10^(-3);各成矿期流体密度集中于0.63~0.84 g/cm^(3)之间,均一压力为163~178 MPa,成矿深度<6 km;成矿早期流体属于中高温、低盐度、低密度的CO_(2)—H_(2)O—NaCl变质流体,后期有岩浆水参与。钱台子金矿床形成于扬子克拉通沿NW方向俯冲于华北克拉通之下的造山期后持续伸展背景下的拆沉作用和壳幔相互作用所导致的大规模岩浆活动。Qiantaizi Au deposit is a quartz vein type deposit located at the east end of Bengbu uplift in the east Anhui province.Ore bodies occur manly in Wuhe Group of the metamorphic crystalline basement and are controlled by transtensional fault.Systematic Petr graphic observation,microscopic thermometry,laser Raman probe and H-O isotopic analysis of fluid inclusions of quartz formed at different stages are carried out to discuss material sources and genesis of the deposit.The fluid inclusion includes pure CO_(2) type,CO_(2)+H_(2)O type and H_(2)O+NaCl type.The homogenization temperature is 286-385℃,w(NaCl,eqv)4.80%-12.56%,averagely 8.29%,δ^(18)O_(V-SMOW) of different stage’s quartz 9.0×10^(-3)-15.2×10^(-3),theδ^(18)OH_(2)O 2.12×10^(-3)-9.70×10^(-3),fluid density for each metallogenic stage 0.63-0.84 g/cm3,homogeneous pressure 163~178 MPa,the metallogenic depth less than 6 km.In the early metallogenic stage the fluid is the CO_(2)-H_(2)O-NaCl metamorphic fluid with medium-high temperature,low salinity and density.In the late metallogenic stage magmatic water incorporated.The Au deposit should be formed during large-scale magmatism resulted from delamination and interaction of the crust and mantle under background of post-orogenic continuous extension due to NE subduction of Yangtze craton under North China craton.

关 键 词：钱台子金矿床 流体包裹体 氢氧同位素 成矿流体 安徽省 

分 类 号：P618.51[天文地球—矿床学] P611.1[天文地球—地质学]