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高校地质学报 ›› 2023, Vol. 29 ›› Issue (2): 201-212.DOI: 10.16108/j.issn1006-7493.2021058

• 岩石·矿床·地球化学 • 上一篇    下一篇

辽宁清原中元古代辉绿岩的年代学、地球化学特征及其地质意义

苏祖敏1,孙丰月1,2*,张雅静1   

  1. 1. 吉林大学 地球科学学院,长春 130061;
    2. 吉林大学 国土资源部东北亚矿产资源评价重点实验室,长春 130061
  • 出版日期:2023-04-20 发布日期:2023-04-20

Geochronology, Geochemical Characteristics and Geological Significance of the Mesoproterozoic Diabase in Qingyuan County, Liaoning Province

SU Zumin1,SUN Fengyue1,2*,ZHANG Yajing1   

  1. 1. College of Earth Sciences, Jilin University, Changchun 130061, China;
    2. Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources,
    Jilin University, Changchun 130061, China
  • Online:2023-04-20 Published:2023-04-20

摘要: 辽宁省清原县位于华北克拉通北缘东段,对清原县红透山地区的辉绿岩脉开展了LA-ICP-MS锆石U-Pb定年和全岩地球化学分析,旨在探讨华北克拉通在中元古代时期的构造演化。红透山辉绿岩LA-ICP-MS岩浆锆石U-Pb年龄为1293 Ma±35 Ma,代表该岩体的形成时代。辉绿岩SiO2=49.42%~50.76%、MgO=3.56%~5.83%、Na2O+K2O=3.95%~6.2%,变化于碱性和亚碱性系列之间。微量元素特征显示:相对富集LREE,相对亏损HREE、 HFSE,无明显Eu异常。研究认为红透山辉绿岩为伸展环境下形成的板内玄武岩,其岩浆源于俯冲物质影响的富集岩石圈地幔,并受到一定程度的地壳物质混染。结合前人对华北克拉通北部与东北部中元古代辉绿岩的研究,认为红透山辉绿岩的形成与哥伦比亚超大陆的裂解有关。

关键词: 地球化学, 辉绿岩, 锆石U-Pb定年, 哥伦比亚超大陆, 华北克拉通, 中元古代

Abstract: This study presents LA-ICP-MS Zircon U-Pb dating and whole-rock geochemical analysis of a diabase dyke in Hongtoushan area of Qingyuan County, Liaoning Province, which is located in the northeastern margin of the North China Craton, to explore tectonic evolution of the North China Craton in the Mesoproterozoic. The LA-ICP-MS magmatic zircon U-Pb dating results show an age of 1293 Ma±35 Ma for the Hongtoshan diabase , which represents the emplacement age of the diabase dyke. The diabase shows SiO2=49.42%, MgO=3.56%-5.83%, Na2O+K2O=3.95%-6.2%, indicating transitional characteristics between alkaline and sub-alkaline series. The diabase is enriched in LREE, depleted in HREE and HFSE, and has no obvious Eu anomalies. The Hongtoushan diabase belongs to intraplate basalt that was formed in an extensional setting. The magma was derived from the enriched lithospheric mantle influenced by subducted materials and was assimilated by crustal rocks. Combined with available data on the Mesoproterozoic diabase dykes in the north and northeast of the North China Craton, it is suggested that the diabase was formed during the breakup of Columbia supercontinent.

Key words: geochemistry, diabase, zircon U-Pb dating, Columbia supercontinent, North China Craton, Mesoproterozoic

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