| 西部华夏地区深部可能存在与华北和扬子大陆相似的太古代基底 |
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| 引用本文： | 郑建平,Griffin WL,汤华云,张志海,苏玉平,刘观亮.西部华夏地区深部可能存在与华北和扬子大陆相似的太古代基底[J].高校地质学报,2008,14(4):549-557. |
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| 作者姓名： | 郑建平 Griffin WL 汤华云 张志海 苏玉平 刘观亮 |
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| 作者单位： | 1. 中国地质大学 地球科学学院，地质过程与矿产资源国家重点实验室，武汉 430074；2. GEMOC ARC National Key Centre, Macquarie University, NSW 2109, Australia；3. 宜昌地质矿产研究所，湖北 宜昌 433003 |
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| 基金项目： | 国家自然科学基金
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地质过程与矿产资源国家重点实验室科技部专项经费资助项目
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| 摘 要： | 华夏地区是否存在古陆是一个长期争论的问题。火山作用的天然超深钻取样，提供了探索大陆基底属性和形成演化过程的重要手段。西部华夏地区地表所出露的最古老岩石不老于中元古代，但对广西省东南部晚中生代—新生代火山岩中锆石捕虏晶的U-Pb年代学和Lu-Hf同位素研究则表明：与华北和扬子大陆相似，西部华夏地区有未暴露的太古代基底。该基底的主体年龄是2.9~2.5 Ga，也有3.85 Ga，3.55 Ga和3.3~3.2 Ga的年龄等。它们的亏损地幔模式年龄（t DM）为2.5 Ga至≥3.9 Ga。说明西部华夏地区的基底经历了复杂的改造过程，包括3.6~3.2 Ga，2.5 Ga，1.0 Ga和0.5 Ga时的地幔物质加入，以及2.0~1.8 Ga和1.6~1.5 Ga时的地壳再熔融事件等。对西部华夏地区强烈改造岩石圈的认识，将有助于从物质组分角度对华南成矿作用背景的思考。
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| 关 键 词： | 西部华夏 太古代基底 改造作用 锆石 捕虏晶 |
| 修稿时间： | 2008-12-20 |
Archean Basement Similar to the North China and Yangtze Continents May Be Existed beneath the Western Cathaysia |
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| ZHENG Jian-ping,Griffin WL,TANG Hua-yun,ZHANG Zhi-hai,SU Yu-ping,LIU Guan-liang.Archean Basement Similar to the North China and Yangtze Continents May Be Existed beneath the Western Cathaysia[J].Geological Journal of China Universities,2008,14(4):549-557. |
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| Authors: | ZHENG Jian-ping Griffin WL TANG Hua-yun ZHANG Zhi-hai SU Yu-ping LIU Guan-liang |
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| Institution: | 1. Faculty of Earth Sciences, State Key Laboratory of Geological Processes and Minetal Resources,China University of Geoscinces, Wuhan 430047, China;2. GEMOC ARC National Key Centre, Macguarie University, NSW 2109, Austrralia;3. Yichang Institute of Geology and Mineral Resources, Yichang 443003, China |
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| Abstract: | The oldest rocks exposed on the western Cathaysia Block in southeastern (SE) China are younger than Mesoproterozoic.However, the U-Pb and Hf-isotope systematics of xenocrystic zircons, brought to the surface by the Mesozoic-Cenozoic basaltic rocks in Guangxi Province, suggest the presence of unexposed Archean basement, with zircon populations of 3.85 Ga, 3.55 Ga,3.3~3.2 Ga and mainly 2.9~2.5 Ga and Hf model ages (t DM) of 2.5 Ga to ≥3.9 Ga, beneath the western Cathaysia Block. This basement experienced complex modification through time, including the addition of juvenile mantle material at ca 3.6~3.2 Ga, 2.5 Ga, 1.0 Ga and 0.5 Ga. The zircons also record thermal events that reworked (remelted) the older crust of the block at ca 2.0~1.8 Ga and 1.6~1.5 Ga. |
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| Keywords: | western Cathaysia block Archean basement post-Archean modification zircon xenocryst |
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