吉林夹皮沟金矿带岩脉和蚀变绢云母定年及金矿成矿时代  

DATING OF THE DYKES AND ALTERED SERICITE IN JIAPIGOU GOLD ORE BELT, JILIN PROVINCE AND ITS GOLD ORE FORMATION AGE

作　　者：罗镇宽[1] 关康[1] 苗来成[1] 

机构地区：[1]天津地质研究院,天津300061

出　　处：《现代地质》2002年第1期19-25,共7页Geoscience

基　　金：中国和澳大利亚经济技术合作研究基金项目;国家攀登预选项目 ( 95 预 2 5 )

摘　　要：吉林夹皮沟金矿床的矿化年龄一直存在争议。采用先进的SHRIMP测年方法测得夹皮沟二道沟金矿床的花岗闪长岩脉锆石的2 0 6Pb/ 2 3 8U年龄为 (2 2 3± 2 )Ma ;八家子金矿床的石英正长斑岩锆石的2 0 6Pb/ 2 3 8U年龄为 (2 41± 6 )～ (2 18± 6 )Ma。这一结果与前人测得的K Ar年龄基本相符。这两条岩脉与含金石英脉同构造空间 ,形成时代相近 ,因此上述岩脉年龄大体反映了金矿化年龄。同时还测得八家子金矿床蚀变绢云母的 4 0 Ar 3 9Ar等时线年龄为(2 0 3 975± 0 5 2 7)Ma ,进一步证明金矿化发生在中生代印支期。矿石中含有大量的方铅矿 ,还存在矿物及元素的分带 ,这些特征表明夹皮沟金矿床不太可能是新太古代或元古代形成的变质热液矿床 。Mineralization age of the gold deposits in Jiapigou gold ore belt is controversial. The paper presents data of SHRIMP dating on zircon in Jiapigou gold ore belt. 206Pb/? 208U age of the granitic diorite dyke in Erdaogou gold deposit is 223±2 Ma and quartz syenite dyke in Bajiazi gold deposit 241±6 Ma-218±6 Ma. The data are coincided with the previous results dating by K-Ar method. The two dykes occur in the same structural space with the gold-bearing quartz veins thus the age dated approximates that of the gold mineralization. The age of altered sericite from Bajiazi gold deposit dated by 40Ar- 39Ar method is 203.975±527 Ma,which indicates the mineralization took place in Indosinian period of Archean Era. All the data, together with occurrences of many galena and zonations of minerals and elements in Jiapigou gold deposits imply that the gold deposits would be rather magmatic hydrothermal gold deposits related to Mesozoic magmatism than New Archean or Paleo-Archean metamorphic hydrothermal gold deposits.

关 键 词：SHRIMP定年 ^40Ar-^39Ar等时线年龄 岩脉 绢云母 金矿床 吉林 成矿时代 氩同位素 

分 类 号：P618.51[天文地球—矿床学]