胶东夏甸金矿成矿流体及成矿物质来源：H-O、He-Ar、Sr-Nd-Pb同位素证据  

H-O, He-Ar and Sr-Nd-Pb Isotopic Constraints on the Sources of Ore-Forming Fluids and Ore-Forming Materials in the Xiadian Gold Deposit, Jiaodong

作　　者：杜佛光 姜耀辉[1] 青龙[1] 倪春雨[1] DU Foguang;JIANG Yaohui;QING Long;NI Chunyu(State Key Laboratory for Mineral Deposits Research.School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]内生金属矿床成矿机制研究国家重点实验室南京大学地球科学与工程学院

出　　处：《高校地质学报》2019年第5期686-696,共11页Geological Journal of China Universities

基　　金：国家重点研发计划（2016YFC0600107）资助

摘　　要：夏甸金矿是胶东金矿集区中一处大型焦家式矿床。文章在详尽的岩相学和矿相学研究基础上,对该矿床进一步开展了H-O同位素并首次开展了He-Ar和Sr-Nd-Pb同位素示踪研究,为该矿床成矿流体及成矿物质来源提供了新的制约。石英中流体包裹体的H-O同位素(δDV-SMOW=-102.3‰^-93.9‰,δ18OH2O=-0.2‰~1.6‰)揭示出成矿流体主要为富集地幔流体,并有少许大气降水加入;黄铁矿中He-Ar同位素[3He/4/He=0.58×10?6~1.90×10?6(0.42~1.36Ra),40Ar/36Ar=724.7~1358.4]同样表明成矿流体以富集地幔流体为主导;矿石及蚀变岩的Nd-Pb同位素既不同于围岩花岗岩,也不同于基底变质岩,与胶东地区中生代软流圈地幔起源的玄武岩也相差甚远,而与胶东地区中生代富集岩石圈地幔起源的煌斑岩相一致,但它们的初始87Sr/86Sr比值明显高于煌斑岩,甚至高于围岩花岗岩。Sr-Nd-Pb同位素特征表明成矿流体及成矿物质来源于富集岩石圈地幔,并在其上升过程中与基底变质岩发生了相互作用。The Xiadian gold deposit is a large Jiaojia-type gold deposit in Jiaodong district.On the basis of detailed petrographic and mineralogical studies,we carried out the H-O isotopes and the first He-Ar and Sr-Nd-Pb isotope tracing studies of the Xiadian gold deposit,which furnish the new constrains on the source of ore-forming fluids and materials.H-O isotopes of fluid inclusions in quartz(δDV-SMOW=-102.3‰^-93.9‰,δ18OH2O=-0.2‰~1.6‰)reveal that the ore-forming fluids is mainly composed of enriched mantlederivedfluidwithinvolvedalittlemeteoricwater.He-Arisotopeofpyrite[3He/4/He=0.58×10?6~1.90×10?6(0.42~1.36Ra),40Ar/36Ar=724.7~1358.4]also indicates that the ore-forming fluids are dominant by the enriched mantle-derived fluid.Nd-Pb isotopes of ore and altered rocks are different either from those of the surrounding granites and the basement metamorphic rocks or from those of Mesozoic asthenosphere-derived basalts.Instead,they are consistent with those of Mesozoic lithospheric mantle-derived lamprophyres in the Jiaodong district.However,their initial 87Sr/86Sr ratios are higher than those of the lamprophyres and even higher than the surrounding granites.The Sr-Nd-Pb isotopic characteristics indicate that the ore-forming fluids and ore-forming materials were derived from the enriched lithospheric mantle with subsequent interacted with the basement metamorphic rocks during the ascending process.

关 键 词：夏甸金矿 H-O同位素 HE-AR同位素 SR-ND-PB同位素 成矿流体 成矿物质 

分 类 号：P597[天文地球—地球化学]