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现代地质 ›› 2011, Vol. 25 ›› Issue (2): 189-200.

• 岩石学 • 上一篇    下一篇

金沙江—哀牢山断裂带几个富碱斑岩体的锆石U-Pb定年及地质意义

李勇,莫宣学,喻学惠,黄行凯,和文言   

  1. 地质过程与矿产资源国家重点实验室,中国地质大学 地球科学与资源学院,北京100083
  • 出版日期:2011-04-25 发布日期:2011-05-13
  • 作者简介:李勇,男,博士研究生,1984年出生,矿物学、岩石学、矿床学专业,主要从事岩浆岩岩石学研究。 Email:liy9907@126.com。
  • 基金资助:

    国家重点基础研究发展计划“973”项目(2009CB421000);国家自然科学基金项目(40972049,40572046)。

Zircon  U-Pb Dating of Several Selected Alkali-rich Porphyries from the Jinshajiang-Ailaoshan Fault Zone and Geological Significance 

LI Yong,MO Xuan-xue,YU Xue-hui,HUANG Xing-kai,HE Wen-yan   

  1. State Key Laboratory of Geological Processes and Mineral Resources,  School of Earth Sciences and  Resources,
    China University of Geosciences, Beijing100083, China
  • Online:2011-04-25 Published:2011-05-13

摘要:

运用LA-ICP-MS锆石U-Pb同位素定年方法测定了金沙江—哀牢山断裂带内4个富碱斑岩的年龄。结果表明:剑川地区角闪正长斑岩形成时间为(37.6±2.2)Ma,姚安地区黑云母二长斑岩具有2组锆石U-Pb年龄数据,较年轻的一组为(36.86±0.63)Ma,较老的一组为(40.41±0.24)Ma,姚安黑云母角闪正长斑岩的形成时间为(31.8±2.6)Ma,大理九顶山斑状黑云母二长花岗岩的形成时间为(37.93±0.82)Ma。这些富碱斑岩的形成时间与整个滇西地区新生代富碱斑岩岩浆作用高峰期一致,属于青藏高原后碰撞岩浆作用的时间范围,富碱斑岩岩浆活动是对印度—欧亚大陆巨大碰撞的一种响应。

关键词: 富碱斑岩;金沙江&mdash, 哀牢山断裂带; LA-ICP-MS锆石U-Pb定年;新生代;岩浆作用

Abstract:

By using LA-ICP-MS zircon U-Pb dating,the ages of four alkali-rich porphyries from the Jinshajiang-Ailaoshan fault zone have been determined. The results show that the age of the Jianchuan hornblende syenite porphyry is (37.6±2.2) Ma, the age of Yaoan biotite hornblende syenite porphyry is (31.8±2.6)Ma and that of Jiudingshan porphyritic biotite adamellite is (3793±082) Ma. There are,however,two ages for Yaoan biotite monzonitic porphyry, (36.86±0.63)Ma and (40.41±0.24)Ma,respectively. The formation ages of these four porphyries are consistent with the peak timing of formation of the Cenozoic alkalirich prophyries in western Yunnan, and all in the time frame of the post-collision magmatism of the Tibetan Plateau It is believed that the emplacement of the porphyries was a magmatic response to India-Eurasia collision.

Key words: alkali-rich porphyry, Jinshajiang-Ailaoshan fault zone, LA-ICP-MS zircon U-Pb dating, Cenozoic, magmatism

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