地学前缘 ›› 2018, Vol. 25 ›› Issue (4): 1-10.DOI: 10.13745/j.esf.sf.2018.4.45

• 岩(矿)石、地层特征及地质意义 • 上一篇    下一篇

初论微陆块在中亚造山带演化中的作用:以锡林浩特微陆块为例

邵济安,田伟,唐克东,周新华   

  1. 1. 造山带与地壳演化教育部重点实验室; 北京大学 地球与空间科学学院, 北京 100871
    2. 沈阳地质矿产研究所, 辽宁 沈阳 110034
    3. 中国科学院 地质与地球物理研究所 岩石圈演化国家重点实验室, 北京 100029
  • 收稿日期:2018-01-23 修回日期:2018-04-04 出版日期:2018-07-15 发布日期:2018-07-15
  • 作者简介:邵济安(1940—),女,教授,构造地质学专业。E-mail:wangcc@tsinghua.edu.cn
  • 基金资助:
    中国地质调查局项目“中国及邻区海陆大地构造总体框架和演化过程及其资源环境的控制”(121201102000150009)

 Preliminary discussion on the role of microcontinental blocks in the evolution of the Central Asian orogenic belt: taking the Xilinhaote microcontinental block as an example.

SHAO Ji'an,TIAN Wei,TANG Kedong,ZHOU Xinhua   

  1. 1. The Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education; School of Earth and Space Sciences, Peking University, Beijing 100871, China 2. Shenyang Institute of Geology and Mineral Resources, Shenyang 110034, China 3. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
  • Received:2018-01-23 Revised:2018-04-04 Online:2018-07-15 Published:2018-07-15

摘要: 镶嵌状拼合在中亚造山带众多的古老陆壳块体或微陆块,是前期古亚洲洋的特征之一。本文重点讨论的是锡林浩特微陆块,组成微陆块基底的锡林郭勒杂岩既经历了早古生代的构造热事件,也保留了前寒武纪的古老锆石。当晚古生代(C2—P1)造山带遭受到强烈的伸展变形和底侵作用时,锡林浩特微陆块又起到支柱作用:当微陆块的南、北边缘发生裂谷活动时,微陆块内部却保持了稳定的滨浅海相沉积环境;在微陆块受到来自上地幔的底侵作用时,微陆块通过伸展背景下非造山的双峰式岩浆活动,及其与微陆块再次重熔有关的碱性花岗岩侵位,使得陆壳发生进一步的垂向增生和固结,保持了造山带的构造格局。本文讨论的正是在底侵作用的深部背景下认识该区在晚石炭世出现的一些独特的地质现象。

关键词: 微陆块, 中亚造山带, 晚古生代, 固结, 底侵作用

Abstract:  The old continental crustal massifs or inlaid microcontinental blocks in the Central Asia Orogenic Belt characterize a previous PaleoMongolia ocean. Discussed in this work is the Xilinhaote microcontinental block. The Xilinguole complex—basement of the microcontinental block—has experienced the Early Paleozoic tectothermal events yet still contains older Precambrian zircons. The Xilinguole microcontinental block also acted as pillar when the orogenic belt suffered strong extensional deformation and underplating in the Late Paleozoic (C2P1): while rifts occurred at north and south edges of the microcontinental block, a stable littoralneritic facies sedimentary environment was maintained inside the block. At the same time, in the event of underplating from the upper mantle, tectonic structure of the orogenic zone remained stable, as the microcontinental block further accreted vertically and consolidated through certain orogenic bimodal magmatic activity and alkalic granite emplacement associated with block remelting. It has been the purpose of this work to comprehend some of the unique regional geological phenomena that are closely related to underplating during the Late Carboniferous.

Key words: microcontinental block, Central Asia Orogenic Belt, Late Paleozoic, consolidation, underplating

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