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现代地质 ›› 2013, Vol. 27 ›› Issue (1): 67-78.

• 矿床学与地球化学 • 上一篇    下一篇

内蒙古维拉斯托矿床花岗岩类SHRIMP年代学及Hf同位素研究

王新宇1,侯青叶1,王瑾2, 陈岳龙1, 刘金宝3, 王忠3,李大鹏1   

  1. 1中国地质大学 地球科学与资源学院,北京100083;2辽宁省化工地质勘查院,辽宁 锦州121000;
    3内蒙古地质调查院,内蒙古 呼和浩特010020
  • 收稿日期:2012-02-28 修回日期:2012-07-23 出版日期:2013-01-16 发布日期:2013-01-17
  • 通讯作者: 侯青叶,女, 副教授,1978年出生,地球化学专业,主要从事地球化学的教学及科研工作。
  • 作者简介:王新宇,女,硕士研究生,1989年出生,地球化学专业,主要从事大陆动力学地球化学方面的研究。 Email:wangxinyu1371@sina.com。
  • 基金资助:

    国家自然科学基金项目(40603011);内蒙古自治区政府科研基金资助项目 (05-6-YS2)

SHRIMP Geochronology and Hf Isotope of Zircons from Granitoids of the Weilasituo Deposit in Inner Mongolia

WANG Xin-yu1, HOU Qing-ye1, WANG Jin2, CHEN Yue-long1, LIU Jin-bao3, WANG Zhong3,LI Da-peng1   

  1. 1School of Earth Sciences and Resources, China University of Geosciences, Beijing100083, China;
    2Liaoning Geological Survey for Chemical Industry, Jinzhou, Liaoning121000,China;
    3Geological Survey of Inner Mongolia, Hohhot, Inner Mongolia010020, China
  • Received:2012-02-28 Revised:2012-07-23 Online:2013-01-16 Published:2013-01-17

摘要:

维拉斯托铜多金属矿床地处中亚造山带和大兴安岭造山带的叠加复合部位,该矿床花岗岩类锆石SHRIMP U-Pb测年结果显示为(298.0±2.5)Ma、(308.3±4.2)Ma、(313.9±3.4)Ma和(320.5±4.1)Ma,表明该矿区花岗岩类的成岩时代为晚石炭世。岩石地球化学特征表明它们为岩浆弧活动的产物。除花岗闪长岩样品锆石的εHf(t)为-4.1~+4.08外,其他3件黑云母花岗岩、黑云母二长花岗岩、石英闪长岩样品锆石εHf(t)为正值,为+0.4~+9.9,锆石Hf模式年龄的峰值与古亚洲洋发育的时间较为一致,暗示矿区花岗岩类源区物质主要为俯冲的古亚洲洋壳以及少量前寒武纪地壳。矿区花岗岩类系统研究为探讨晚古生代兴蒙造山带的演化过程提供了基础资料,为该铜多金属矿床的成因研究提供了新的证据。

关键词: 维拉斯托矿床, 锆石, U-Pb年龄, Hf同位素, 内蒙古

Abstract:

Weilasituo copper polymetallic deposit is located in the intersection of central Asia orogenic belt and Da Xinganling orogenic belt. The zircon SHRIMP U-Pb dating shows that granitoids ages are (298.0±2.5) Ma,(308.3±4.2) Ma,(313.9±3.4) Ma and (320.5±4.1) Ma,indicating that they formed in Late Carboniferous. Rock geochemistry characteristics shows that the granitoids are the product of magmatic arc activities. Except for the zircons of granodiorites samples with εHf(t) values from -4.1 to+4.08, the zircon εHf(t) values of the other samples are positive, ranging from +0.4 to +9.9. The peak of zircon Hf model age is consistent with the time of Paleo-Asian Ocean development, suggesting that the main source material of granitoids in mining area is the subducted oceanic curst of the Paleo-Asian Ocean and some Precambrian crust. Systematic study on granitoids in mining area may provide the basic information for exploring the evolution of Xinganling-Mongolian orogenic belt in the Late Paleozoic and new evidence for the genesis of copper polymetallic deposit.

Key words: Weilasituo deposit, zircon, U-Pb age, Hf isotope, Inner Mongolia

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