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| Titel |
How did the Tibetan Plateau growth outward to the southwestern Qinling? |
| VerfasserIn |
Xiaobo Tian, Zhen Liu, Zhenbo Wu, Beibei Zhou, Gaochun Wang, Gaohua Zhu, Ping Tan, Shitan Nie, Guiping Yu, Xiaofeng Liang, Zhiming Bai, Yun Chen, Tao Xu, Xi Zhang |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250130507
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| Publikation (Nr.) |
 EGU/EGU2016-10772.pdf |
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| Zusammenfassung |
| In the northeast of the Tibetan Plateau and north of the Sichuan Basin, the topography is decreasing eastward smoothly from 4.5 km in the Ruoergai Basin to 1.5 km in the Qinling. This feature can be interpreted to indicate that lower crustal flow has been diverted around the Sichuan Basin and beneath the southwestern Qinling, resulting in plateau uplift and growth eastward in this area. To address the problem how the Plateau growth outward, we have carried out a densy 160-km long, W-E shot-period seismograph array during July and Augest 2015 with a station spacing of ~500 m and a total 380 shot-peroid seismographs. During one month observation, 35 teleseismic event with a magnitude larger than 5.0 mw and a epicentral distance of 30-90 degree are recorded. P-wave receiver functions are calculated from 3-component-waveforms and used to imaging interfaces (or discontinuity of velocity of S-wave) in the crust and upper mantle. Our results show that the Moho is flat and imaged at 50 km depth by a strong P-to-S amplitude beneath the Ruoergai Basin. A weak interface can be found at depth ~20 km beneath the Basin. In contrast, a weak and flexural Moho is presented in a depth range of 40-50 km beneath the Minshan. A strong interface is also shown in the crust beneath the Minshan. The interface is west dipping steeply with a maximum depth of 40 km beneath the Minjiang Fault, and eastward become flat with a depth of 15 km beneath Minshan. This structure feature can be interpreted to indicate thrusting block by block eastward rather than lower crustal flow causing active plateau uplift in this area. |
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