| 中国东部岩石圈减薄研究中的几个问题 |
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| 引用本文： | 吴福元,葛文春,孙德有,郭春丽.中国东部岩石圈减薄研究中的几个问题[J].地学前缘,2003,10(3):51-60. |
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| 作者姓名： | 吴福元 葛文春 孙德有 郭春丽 |
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| 作者单位： | 1. 中国科学院地质与地球物理研究所,北京,100029;吉林大学地球科学学院,吉林长春,130061
2. 吉林大学地球科学学院,吉林长春,130061 |
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| 基金项目： | 国家自然科学基金资助项目 (4 0 2 72 0 45 ,40 13 3 0 2 0 )，中国地质调查局基础研究项目 (2 0 0 113 0 0 0 0 5 2 ) |
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| 摘 要： | 中国东部岩石圈减薄是近 10年来国内外研究的热门课题 ,但关于岩石圈减薄的具体时间、机制及其构造控制因素 ,多有争论。根据目前的研究资料 ,文中对上述问题进行了全面的讨论。初步认为该岩石圈减薄发生在晚中生代 ,且在 12 0～ 130Ma的早白垩世达到高潮。综合分析认为 ,岩石圈的减薄与东侧太平洋板块的俯冲有关 ,即大洋板块的俯冲作用导致岩石圈加厚 ,进而发生岩石圈拆沉。Os同位素资料显示 ,由地幔橄榄岩包体所反映的新生代岩石圈地幔具有年轻性质 ,与古生代时的岩石圈地幔截然不同。因此笔者认为 ,中国东部现今的岩石圈地幔并不是减薄后的残留 ,它表明中生代时 ,岩石圈地幔和部分下地壳一起通过拆沉作用而沉入软流圈地幔 ,由此而导致软流圈地幔与地壳的直接接触。幔源岩浆的底侵及软流圈对地壳的直接加热作用 ,使上覆地壳发生大规模的岩浆和成矿作用 ,并导致中国东部中生代时期伸展构造的广泛发育。
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| 关 键 词： | 岩石圈减薄 中生代 中国东部 |
| 文章编号： | 1005-2321(2003)03-0051-10 |
| 修稿时间： | 2003年2月18日 |
DISCUSSIONS ON THE LITHOSPHERIC THINNING IN EASTERN CHINA |
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| WU Fu-yuan.DISCUSSIONS ON THE LITHOSPHERIC THINNING IN EASTERN CHINA[J].Earth Science Frontiers,2003,10(3):51-60. |
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| Authors: | WU Fu-yuan |
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| Institution: | WU Fu-yuan~ |
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| Abstract: | The lithospheric thinning in eastern China is a warmly discussed topic in the last decade. It is not clear, however, about its time, mechanism and tectonic controlling factor for this kind of geodynamic phenomena. According to the up-dated data, a comprehensive review for these questions is given in this paper. It is suggested that the lithospheric thinning took place in the Late Mesozoic, and maximally thinned in Early Cretaceous (120～130 Ma). It is thought that the lithospheric thinning was related to the subduction of Pacific plate in the east, which resulted in the lithospheric thickening and subsequent delamination. The Os isotopic data from the mantle xenoliths in the Cenozoic basalts suggested that the lithospheric mantle in the Cenozoic is juvenile, much different from that in the Paleozoic, which indicated that the present lithospheric mantle is not the residue after the thinning. Therefore, it is proposed that whole lithospheric mantle with part of the lower crust was delaminated, which resulted in the direct contact between the asthenospheric mantle and crust. The heating from the asthenosphere on the crust subsequently resulted in the intensive magmatism, mineralization, and widespread development of extensional structures in eastern China. |
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| Keywords: | lithospheric thinning Mesozoic eastern China |
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