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J4 ›› 2012, Vol. 18 ›› Issue (1): 158-163.

• 其他学科论文 • 上一篇    下一篇

南祁连乙什春基性-超基性岩体LA-ICP-MS锆石 U-Pb年龄及其地质意义

余吉远,李向民,马中平,王国强,唐 卓,孙吉明,武 鹏   

  1. 中国地质调查局 西安地质矿产研究所,西安 710054
  • 收稿日期:2011-10-08 修回日期:2011-11-14 出版日期:2012-03-20 发布日期:2012-03-20
  • 通讯作者: 余吉远,1978年生,男,硕士,助理研究员,从事区域地质、区域矿产调查研究;E-mail:yujiyuan111@163.com
  • 作者简介:余吉远,1978年生,男,硕士,助理研究员,从事区域地质、区域矿产调查研究;E-mail:yujiyuan111@163.com
  • 基金资助:

    青藏专项“北祁连成矿带成矿条件研究与找矿靶区优选”(1212010818090);中国地质调查局大调查项目“北山—祁连成矿带
    地质矿产综合研究”(1212010010405)

Zircon U-Pb Dating of the Yishichun Mafic-Ultramafic Complex From Southern Qilian and its Geological Significance

YU Jiyuan, LI Xiangmin, MA Zhongping, WANG Guoqiang, TANG Zhuo, SUN Jiming, WU Peng   

  1. Xi,an Institute of Geology and Mineral Resource, China Geological Survey, Xi,an 710054, China
  • Received:2011-10-08 Revised:2011-11-14 Online:2012-03-20 Published:2012-03-20
  • Contact: Yu Jiyuan, Master D.; E-mail:yujiyuan111@163.com
  • About author:Yu Jiyuan, Master D.; E-mail:yujiyuan111@163.com

摘要:

       研究区位于中祁连地块南缘, 青海湖南- 古雷深大断裂南侧,是祁连成矿带铜镍矿找矿最有利地区。铜镍矿矿体产于
同源同期侵入的基性- 超基性岩体内, 铜镍矿化无论在时间上和空间上都与岩体的侵位密切相关。本次研究对乙什春基性-
超基性岩体中的锆石进行了阴极发光(CL) 成像观察, 结合Th/U比值特征,显示其为岩浆成因;并应用LA-ICP-MS 对锆石微
区U-Pb 年龄进行了测定,获得乙什春含矿岩体中锆石加权平均年龄为(455.1±1.7) Ma,表明其含矿岩体的侵位及矿化作
用发生于晚奥陶世,成岩成矿的动力学背景为陆缘裂谷构造环境。

关键词: 基性-超基性侵入岩, LA-ICP-MS, 锆石U-Pb定年, 铜镍矿, 南祁连

Abstract:

      The study area is located at the southern margin of the Middle Qilian, south of the Qinghai Lake—GuLei deep fault
belt, which is a favorable area for copper-nickel deposits in Qilian metallogenic belt. Yishichun Copper-nickel ore occurs within the homologous and contemporaneous basic-ultrabasic intrusions, and copper-nickel mineralization is spatially and temporally related to the intrusive rocks. The cathodoluminescence (CL) images and the Th/U ratios of zircons from the basic-ultramafic rocks suggest that zircon crystals are of magmatic origin; The LA-ICP-MS U-Pb dating of these zircons yields a weighted mean age of 455.1±1.7 Ma. Therefore, the ore-bearing rock emplacement and copper-nickel mineralization occurred during the late Ordovician, and the metallogenic dynamic process was probably related to an ancient continental margin rifting.

Key words: 基性-超基性侵入岩;LA-ICP-MS;锆石U-Pb定年;铜镍矿;南祁连

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