胶东地区金矿床流体包裹体的He、Ar同位素组成及成矿流体来源示踪  

Helium and argon isotopic compositions of fluid inclusions and tracing to the source of ore-forming fluids for Jiaodong gold deposits

作　　者：张连昌[1] 沈远超[1] 李厚民[1] 曾庆栋[1] 李光明[1] 刘铁兵[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》2002年第4期559-565,共7页Acta Petrologica Sinica

基　　金：中国科学院创新工程重大项目 ( KZCX1 - Y- 0 3);国家"973"项目"大陆深俯冲作用"( G1 9990 7550 4 )资助

摘　　要：关于胶东地区金矿床成因 ,多年来一直存在较大的争议。代表性金矿床中黄铁矿流体包裹体的 He-Ar组成表明 ,胶东金矿床黄铁矿流体包裹体的 3 He/ 4 He比值为 0 .43～ 2 .3 6R/ Ra。该值可分为两组 :一组如蓬家夼金矿和发云夼金矿3He/ 4 He比值 <1.0 R/ Ra;另一组如邓格庄和焦家金矿 3He/ 4 He比值 >1.0 R/ Ra。蓬家夼 -发云夼金矿成矿流体的 4 0 Ar/ 3 6 Ar比值为 3 93～ 3 10 ,比较接近于大气氩的同位素组成 (40 Ar/ 3 6 Ar=2 95.5) ,而焦家金矿成矿流体的 4 0 Ar/ 3 6 Ar比值为 50 0～ 114 8。He-Ar同位素系统显示了蓬家夼 -发云夼金矿成矿流体来源以大气降水为主 ,邓格庄、焦家金矿成矿流体来源以地幔流体为主。进一步研究表明 ,胶东金矿成矿流体 H-O和The Jiaodong gold deposits have attracted the attention of many geologists and their metallogenesis has long been in dispute. The authors choose pyrite samples from some gold deposits in Jiaodong area to analyze their helium and argon isotopic compositions of fluid inclusions. The analytical results show that He-3/He-4 ratios of Jiaodong gold deposits are 0.43similar to2.36 R/Ra, and He-3/He-4 < 1.0 R/Ra for Pengjiakuank and Fayunkuang gold deposit, He-3/He-4 > 1.0 R/Ra for Denggezhuang and Jiaojia gold deposit. Ar-40/Ar-36 ratios of ore-forming fluids are 393similar to310 for Pengjiakuang and Fayunkuang gold deposits, similar to the isotopic components of atmosphere helium (Ar-40/Ar-36 = 295.5) Ar-40/Ar-36 ratios of Jiaojia and Denggezhuang gold deposits are 500similar to1148. The compositions of He-Ar isotopic system suggest that the source of ore-forming fluids is mainly meteoric water for Pengjiakuang and Fayunkuang gold deposits, and mantle fluids for Denggezhuang and Jiaojia gold deposits. The relation between H-O and He-Ar isotopic systems of ore-forming fluids show consistency in Jiaodong gold deposits.

关 键 词：成矿流体 HE-AR同位素 地幔流体 金矿床 胶东地区 大气降水 

分 类 号：P618.51[天文地球—矿床学] P597[天文地球—地质学]