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Seismic evidence for stepwise thickening of the crust across the NE Tibetan plateau |
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| Authors: | Jérome VergneGérard Wittlinger Qiang HuiPaul Tapponnier Georges PoupinetJiang Mei Georges HerquelAnne Paul |
| Institution: | a Institut de Physique du Globe de Strasbourg, Centre National de la Recherche Scientifique, Université Louis Pasteur, 5 rue Descartes, 67084 Strasbourg, France b Institute of Mineral Deposits, Chinese Academy of Geological Sciences, Baiwanzhuang Road, 100037 Beijing, PR China c Laboratoire de Tectonique, Institut de Physique du globe de Paris, 4 place Jussieu, 75205 Paris, France d Laboratoire de Géophysique Interne et Tectonophysique, Centre National de la Recherche Scientifique, Université Joseph Fourier, Boite Postale 53, 38041 Grenoble, France |
| Abstract: | We performed a receiver function analysis on teleseismic data recorded along two 550 km-long profiles crossing the northeastern Tibetan plateau. Results from time to depth migration, grid-search Vp/Vs determination and simulated annealing inversion of waveforms, reveal that the crust thickens from ∼50 km near the northern edge of the plateau to ∼80 km south of the Jinsha suture in the Qiang Tang block. Crustal thickening occurs in staircase fashion with steps located beneath the main, reactivated sutures. The Vp/Vs ratio, close to the global continental average does not suggest widespread partial melting but rather a more usual separation between an upper felsic and a lower mafic part within the northeastern Tibetan crust. |
| Keywords: | teleseismic signals crust velocity S-waves P-waves Qinghai-Xizang Plateau |
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