Abstract

中条山地区发育大量弱变质或未变质的中基性岩墙,它们是华北克拉通中元古代初期(1.80~1.76 Ga)大规模岩墙群的重要组成部分,准确厘定其侵位时代对构建岩墙群的精细时-空分布规律,以及认识华北克拉通该时期地球动力学过程有重要意义. 此次研究对永济王庄村附近的一条近东西向岩墙开展了斜锆石离子探针定年,获得其207Pb/206Pb年龄为1799±4 Ma (n=20, MSWD=2.2). 该年龄有效填补了关键地区岩墙群的时代空缺,为揭示华北中元古代初期复合岩墙群中熊耳(1800~1785 Ma)和太行(1770~1760 Ma)两个不同世代岩墙群的形成时代和空间分布特征提供了重要线索. 同时,中条山1799 Ma中-基性岩墙也是目前报道的华北克拉通最老的未变质岩墙,作为熊耳期岩浆活动可能的开端,它不仅为限定熊耳群火山岩系底界年龄提供了重要参考,也为以大火成岩省(或岩墙群)为标志的地体对比和超大陆重建提供了新的依据. 综合岩墙群的几何学、年代学和地球化学特征,文章支持熊耳、太行岩墙群是地幔柱在不同阶段作用于运动的华北克拉通大陆板块岩石圈的产物.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.