湘东北雁林寺金矿床成矿物质来源及成矿流体类型

雁林寺金矿位于雪峰弧形构造带(江南造山带湖南段)东段,是湘东北地区一个较为典型的金矿床。本文在前人研究的基础上,统计分析了矿区不同地质体Au元素含量、稀土元素地球化学、微量元素地球化学特征,对比研究了矿区含金石英的H-O同位素、Sr同位素地球化学特征及成矿流体组成特征。提出赋矿围岩冷家溪群浊积岩在沉积阶段就具有明显的金富集。矿区矿石、(矿化)蚀变围岩、未蚀变围岩稀土、微量元素地球化学特征呈现出高度相似性。含金石英的H-O同位素地球化学、Sr同位素地球化学及成矿流体成分特征表明成矿流体为变质流体。综合矿区地质特征、不同地质体金含量、稀土-微量元素地球化学特征、H-O同位素、Sr同位素及成矿流体成分特征,认为地层中的金元素为雁林寺金矿床提供了成矿物质。

A Study of the Source of Metallogenic Material and Characteristics of the Ore-forming Fluid in the Yanlinsi Gold Deposit in Northeastern Hunan Province

The Yanlinsi gold deposit, located in the eastern part of Xuefeng arc structure belt (Hunan section of the Jiangnan orogenic belt), is a typical gold deposit in northeast Hunan Province. In this paper, the authors investigated gold content in different geological bodies, H-O isotope geochemistry, Sr isotope geochemistry and composition of ore-forming fluids in gold-bearing quartz. It is held that gold was quite rich in the Lengjiaxi Group during the sedimentation. The geochemistry of rare earth elements and trace elements in ores, altered rocks and unaltered rocks shows high similarity. According to the characteristics of Sr isotope geochemistry and H-O isotope geochemistry, the composition of ore-forming fluids in gold-bearing quartz was probably metamorphic fluids. This study, combined with geological characteristics, gold content in different geological bodies, geochemistry of rare earth elements and trace elements, H-O isotope geochemistry, Sr isotope geochemistry and composition of ore-forming fluids in gold-bearing quartz, the authors hold that the Lengjiaxi Group provided ore-forming materials during ore-forming process.