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现代地质 ›› 2012, Vol. 26 ›› Issue (5): 1008-1018.

• 地球化学 • 上一篇    下一篇

北山月牙山蛇绿岩地球化学特征及SHRIMP定年

 侯青叶1, 王忠2, 刘金宝2 王瑾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 内蒙古地质调查院,内蒙古 呼和浩特010020;3  辽宁省化工地质勘查院,辽宁 锦州121000
  • 收稿日期:2012-07-16 修回日期:2012-08-16 出版日期:2012-10-19 发布日期:2012-10-23
  • 作者简介:侯青叶,女,副教授,1978年出生,地球化学专业,主要从事区域地球化学和环境地球化学的教学和科研工作。Email:qingyehou@cugb.edu.cn。
  • 基金资助:

    国家自然科学基金项目(40603011)。

Geochemistry Characteristics and SHRIMP Dating of YueyashanOphiolite in Beishan Orogen

 HOU  Jing-Xie-1, WANG  Zhong-2, LIU  Jin-Bao-2, WANG  Jin-3, LI  Da-Feng-1   

  1. 1 School of Earth Sciences and Resources, China University of Geosciences, Beijing100083, China; 2 Geological Survey of Inner Mongolia, Hohhot, Inner Mongolia010020, China; 3 Liaoning Geological Survey for Chemical Industry, Jinzhou, Liaoning121000 , China
  • Received:2012-07-16 Revised:2012-08-16 Online:2012-10-19 Published:2012-10-23

摘要:

北山造山带是天山—兴蒙造山带的关键枢纽地带,该地区蛇绿岩系统的地质—地球化学研究,对于探讨中亚造山带的演化有着非常重要的意义。系统报道了月牙山蛇绿岩的主量元素、微量元素、Sr-Nd/Pb-Hf同位素组成及SHRIMP年代学研究成果。蛇绿岩套中斜长花岗岩的精细SHRIMP锆石U-Pb年龄为(536±7) Ma,表明该蛇绿岩形成于早寒武世晚期。月牙山蛇绿岩中蚀变橄榄岩、变基性岩系统的地球化学特征推测其应形成于与岛弧无关的构造环境。结合区域地质特征分析表明它应形成于板内深大断裂—初始裂谷演化至陆间有限小洋盆构造环境。

关键词: 北山, 中亚造山带, 蛇绿岩, 地球化学, SHRIMP定年

Abstract:

Beishan Orogen is a key area of Tianshan Xing'an Mongolian Orogen. The geological geochemical study on the ophiolite units from the region will be of great significance for the evolution research of the Central Asian orogenic belt. This research focuses on major elements, trace elements, Sr-Nd/Pb-Hf isotopic compositions and SHRIMP geochronology of the Yueyashan ophiolite suites in Beishan. The fine zircon SHRIMP U-Pb age of plagiogranite is (536±7) Ma, showing that the ophiolites formed in the late Early Cambrian. The geochemical characteristics of the alteratic peridotite and metabasic rocks of the Yueyashan ophiolites indicate that the ophiolites formed in the mid-ocean ridge environment independent of island arcs.  With respect to the regional geological features,this paper suggests that the Yueyashan ophoplites formed in a tectonic setting of intraplate discordogenic fault   the original rift evolving to a limited small oceanic basin.

Key words: Beishan; Central Asia , orogenic belt; ophiolite; , geochemistry, zircon SHRIMP U-Pb age