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| Upper crustal structure under Jingtai–Hezuo profile in Northeastern Tibet from topography-dependent eikonal traveltime tomography |
| Ting Ma1,2, Zhongjie Zhang1, Peng Wang2,3, Yingkang Li4 |
1 State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
4 Geological Material Center, China Geology Survey, Yanjiao 065201, Hebei, China |
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Abstract The Northeastern Tibetan plateau records Caledonian Qilian orogeny and Cenozoic reactivation by continental collision between the Indian and Asian plates. In order to provide the constraint on the Qilian orogenic mechanism and the expansion of the plateau,wide-angle seismic datawas acquired along a 430 km-long profile between Jingtai and Hezuo. There is strong height variation along the profile, which is dealt by topography flattening scheme in our crustal velocity structure reconstruction. We herein present the upper crustal P-wave velocity structure model resulting from the interpretation of first arrival dataset from topography-dependent eikonal traveltime tomography. With topography flattening schemeto process real topography along the profile, the evenness of ray coverage times of the image area (upper crust) is improved, which provides upper crustal velocity model comparable to the classic traveltime tomography (withmodel expansion scheme to process irregular surface). The upper crustal velocitymodel shows zoning character whichmatches with the tectonic division of the Qaidam-Kunlun-West Qinling belt, the Central and Northern Qilian, and theAlax blocks along the profile. The resultant upper crustal P-wave velocity model is expected to provide important base for linkage between the mapped surface geology and deep structure or geodynamics in Northeastern Tibet.
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Received: 26 July 2013
Published: 03 January 2014
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| Fund:the Ministry of Science and Technology of China (2011CB808904), the Ministry of Land and Resources of China (SinoProbe-02-02 or 201011041, SinoProbe-03-02 or 201011047), and the National Nature Science Foundation of China (41174075, 41021063, 41274090 and 41174043) |
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Corresponding Authors:
Ting Ma
E-mail: grace@mail.iggcas.ac.cn
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