| 西藏高原上地幔的精细结构与构造——地震层析成像给出的启示 |
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| 引用本文： | 赵文津,薛光琦,吴珍汉,赵逊,刘葵,史大年,J.Mechie,D.Nelson,L.Brown,T.Hearn.西藏高原上地幔的精细结构与构造——地震层析成像给出的启示[J].地球物理学报,2004,47(3):449-455. |
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| 作者姓名： | 赵文津 薛光琦 吴珍汉 赵逊 刘葵 史大年 J.Mechie D.Nelson L.Brown T.Hearn |
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| 作者单位： | 1.中国地质科学院, 北京 100037 2 中国地质科学院矿产资源研究所, 北京 100037 3 中国地质科学院地质力学研究所, 北京 100081 4 GeoForchungsZentrum (GFZ), Potsdam 14473, Germany 5 Department of Earth Sciences, Syracuse University, Syracuse, New York 13244, USA 6 Department of Geological Scienc |
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| 基金项目： | 原地质矿产部，国土资源部基金项目 (950 1 2 0 7)，美国国家科学基金会资助项目 (grantEAR 961 4 61 6)，德国研究协会，德国地学研究中心的资助项目 |
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| 摘 要： | 用布置在亚东—格尔木的164个流动地震台站记录的926个远震事件的24241条射线，进行远震P波层析成像处理，高分辨率的西藏高原上地幔的速度结构图,显示了印度巨厚地幔岩石圈在向高原之下推进的过程中,在高喜马拉雅之下拆分成上、下两层，这是发生的第一次拆沉. 下层从高喜马拉雅以下约以22°的角度向高原北部插入到350km 深；而其上层则向北伸展直到雁石坪，并构成了高原薄的地幔岩石圈. 在雁石坪北（33.7°N），当其与亚洲大陆岩石圈地幔相遇后发生断离并下沉. 再次证实了五道梁（35.27°N）深部低速体的存在，本区内地壳内低速物质可能与上述运动有联系,反映了深层热物质的上涌.
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| 关 键 词： | P波成像 青藏高原 上地幔结构 地幔岩石圈 拆沉 |
| 文章编号： | 0001-5733(2004)03-0449-07 |
| 收稿时间： | 2003-7-2 |
| 修稿时间： | 2003-12-20 |
Fine velocity structure of the upper mantle beneath the Xizang plateau from tomography and its geological interpretations |
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| ZHAO Wen Jin XUE Guang Qi WU Zhen Han ZHAO Xun LIU Kui SHI Da Nian J. Mechie D. Nelson L. Brown T. Hearn Chinese Academy of Geological Sciences,Beijing ,China Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing ,China Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing ,China GeoForchungsZentrum.Fine velocity structure of the upper mantle beneath the Xizang plateau from tomography and its geological interpretations[J].Chinese Journal of Geophysics,2004,47(3):449-455. |
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| Authors: | ZHAO Wen Jin XUE Guang Qi WU Zhen Han ZHAO Xun LIU Kui SHI Da Nian J Mechie D Nelson L Brown T Hearn Chinese Academy of Geological Sciences Beijing China Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing China Institute of Geomechanics Chinese Academy of Geological Sciences Beijing China GeoForchungsZentrum |
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| Abstract: | We use 24241 rays from 926 distant events recorded at 164 portable stations along the line Yadong Golmud to perform teleseismic P wave tomography. Our aim is to obtain the veloci ty structure of the upper mantle beneath the Xizang Plateau with high resolution. Our result shows that the thick lithospheric mantl e of the India plate is divided into two layers beneath the High Himalayas durin g the underthrusting of India below the plateau, representing the first time of its delamination. The lower layer underthrusts beneath the High Himalayas at a a bout 22° angle northward to depth 350km and the upper layer extends northward t o Yanshiping, forming the thin lithospheric mantle below the plateau. North to Y anshiping (33.7°N), the upper layer of the Tibetan mantle fractures and sinks w hen it meets the lithosphere of the Asia continent. Our result also confirms the existence of a deep low velocity body beneath Wudaoliang (35.27°N). We sugges t that this low velocity body in the crust may be associated with upwelling of h ot materials at depth. |
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| Keywords: | P wave tomography Xizang Plateau Upper mantle structure Lithospheric mantle Delamination |
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