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现代地质 ›› 2005, Vol. 19 ›› Issue (2): 198-204.

• 岩石学 • 上一篇    下一篇

湖南宝山花岗闪长质隐爆角砾岩的岩石学、地球化学特征及锆石SHRIMP定年

伍光英1,2,马铁球3,柏道远3,李金冬1,3,车勤建1,3,王先辉3    

  1. 1中国地质大学 地球科学与资源学院,北京100083;
    2宜昌地质矿产研究所,湖北 宜昌443003;
    3湖南省地质矿产勘查开发局,湖南 长沙410011
  • 收稿日期:2004-11-28 修回日期:2005-03-06 出版日期:2005-02-20 发布日期:2005-02-20
  • 作者简介:伍光英,男,高级工程师,博士研究生,1965年出生,矿物学、岩石学、矿床学专业,主要从事基础地质调查的研究工作。
  • 基金资助:

    中国地质调查局国土资源大调查项目(1212010310206);中国地质调查局区域地质调查项目(200213000035)。

Petrological and Geochemical Characteristics of Granodioritic Cryptoexplosion Breccia and Zircon SHRIMP Dating in the Baoshan Area, Hunan Province  

WU Guang-ying1,2, MA Tie-qiu3, BAI Dao-yuan3, LI Jin-dong1,3, CHE Qin-jian1,3, WANG Xian-hui3   

  1. 1 School of Earth Sciences & Resources, China University of Geosciences, Beijing100083, China;
    2 Yichang Institute of Geology and Mineral Resources, Yichang, Hubei443003, China;
    3 Hunan Bureau of Geology and Mineral Resources Exploration and Development, Changsha, Hunan410011, China
  • Received:2004-11-28 Revised:2005-03-06 Online:2005-02-20 Published:2005-02-20

摘要:

通过湖南宝山地区花岗闪长质隐爆角砾岩体的岩石学、地球化学特征的研究,表明岩体中的角砾与基质岩石的特征大致相近,均为高钾钙碱性准铝质花岗质岩石,其成因为壳-幔同熔型。锆石SHRIMP U-Pb定年研究表明,隐爆角砾岩中花岗闪长斑岩的角砾岩石年龄为(164.1±1.9)Ma,基质岩石年龄为(162.2±1.6)Ma,表明两者的形成时间相近,是燕山期构造岩浆作用的产物。隐爆角砾岩体的岩石学、地球化学特征又与其共生的含矿花岗闪长斑岩体相似,岩体中的角砾与基质岩石中的W、Mo、Cu、Pb、Zn成矿元素丰度都很高,其周围有利部位也有矿化,说明隐爆角砾岩体同样可为成矿母岩,这对该区岩体成因及其多金属矿成矿作用的研究具有重要的意义。

关键词: 花岗闪长质隐爆角砾岩, 岩石学及地球化学特征, 锆石SHRIMP定年, 宝山, 湖南

Abstract:

The study on the cryptoexplosion breccia in petrology and geochemistry indicates that the breccia and matrix are high potassium calc-alkaline metaluminous granodiorite, which formed through crust-mantle interaction.Zircon SHRIMP dating shows that breccia of granodriorite yields 207Pb/206Pb age of 164.1±1.9 Ma, and matrix of granodiorite yields 162.2±1.6 Ma. Both breccia and matrix almost formed at the same time. Petrological and geochemical characteristics of granodioritic cryptoexplosion breccia are the same as ore-bearing granodiorite porphyry. The contents of metallogenic elements, such as W, Mo, Cu, Pb, Zn, etc., are very high in the breccia and matrix. And there are some polymetallic mineralizations in the boundary between granodioritic cryptoexplosion breccia and country rocks. It infers that granodioritic cryptoexplosion breccia may be the ore-bearing parent rock as well.So this has a very important significance to exploring more polymetallic ore deposits in the research area.

Key words: granodioritic cryptoexplosion breccia, petrological and geochemical characteristics, zircon SHRIMP dating, Baoshan, Hunan

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