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现代地质 ›› 2004, Vol. 18 ›› Issue (4): 524-528.

• 岩石与矿床地质 • 上一篇    下一篇

安徽铜陵新桥铜-金矿床的He、Ar同位素组成及其意义

王彦斌1,曾普胜2,李延河2,蒙义峰2,杨竹森2,田世洪2   

  1. 1.中国地质科学院 地质研究所,北京 100037;
    2.中国地质科学院 矿产资源研究所,北京 100037
  • 收稿日期:2004-05-10 修回日期:2004-07-08 出版日期:2004-04-20 发布日期:2004-04-20
  • 作者简介:王彦斌,男,研究员,1966年出生,地球化学专业,主要从事同位素地质年代学和地球化学的研究工作。
  • 基金资助:

    国土资源部国际合作与科技司重点项目(20010209)。

ORIGIN OF ORE-FORMING FLUIDS OF THE XINQIAO Cu-Au DEPOSIT IN THE TONGLING MINERAL DISTRICT, ANHUI: EVIDENCE FROM He AND Ar ISOTOPES

WANG Yan-bin1, ZENG Pu-sheng2,Li Yan-he2,MENG Yi-feng2, YANG Zhu-sen2, TIAN Shi-hong2   

  1. 1. Institute of Geology, Chinese Academy of Geological Sciences, Beijing  100037, China
    2. Institute of Mineral Resource, Chinese Academy of Geological Sciences, Beijing  100037, China
  • Received:2004-05-10 Revised:2004-07-08 Online:2004-04-20 Published:2004-04-20

摘要:

对安徽铜陵新桥铜-金矿床层状矿体和块状矿体的黄铁矿进行了流体包裹体的He、Ar
同位素研究。结果表明,成矿流体的N(40Ar)/ N(36Ar)≈238~293,N(3He)/ N(4He)≈1.03~1.23Ra,与大气饱和水(包括大气降水和海水)的特征值N(3He)/ N(4He)=1Ra,N(40Ar)/ N(36Ar)=295.5非常接近,表明成矿流体含大气降水和海水,这与野外地质特征也相符合,反映了成矿流体来自海底喷流(热水)沉积作用过程,这一认识为该区铜-金矿床可能的海底热液喷流成因提供了新的证据。

关键词: He和Ar同位素, 流体包裹体, 新桥, 铜陵, 安徽

Abstract:

The ore genesis model of the Xinqiao Cu-Au deposit in Tongling of Anhui Province has long been in dispute, and the major debate focuses on whether the stratiform orebodies formed during the Yanshanian magmatic-hydrothermal event or they were products of carbonferious syn-sedimentary exhalative-hydrothermal event. The paper presents helium isotope data from fluid inclusions of five pyrites. The pyrites were collected from the stratiform orebodies in the deposit, and their 3He/4He ratios are significantly higher than 1, range from 1.2 to 1.22 Ra, which indicateds a mantle component in the responsible hydrothermal fluids. It is suggested that the ore-forming fluids were a mixture of deep circulating seawater and a mantle-derived fluids, which are similar to many of those modern submarine hydrothermal fluids. The data provide a new evidence that favor the submarine exhalative-hydrothermal origin for the stratiform mineralization in Xinqiao Cu-Au deposit.

Key words: He and Ar isotopes, crustal fluid, mantle fluid, Xinqiao Cu-Au deposit, Tongling, Anhui

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