Vertical coherence of deformation in lithosphere in the NE margin of the Tibetan plateau using GPS and shear-wave splitting data

Chang, Ling; Ding, Zhongli; Wang, Chunyong; Flesch, L. M.

doi:10.1016/j.tecto.2017.01.025

Cited by 91 publications

(103 citation statements)

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“…Yu and Chen () reported W‐E fast polarization SKS splitting with >1.5‐s delay time beneath the Weihe rift and the Qinling orogeny, along the southern corner of Ordos block, suggesting the eastward asthenospheric flow from the Tibetan Plateau. Our study may further indicate the presence of asthenospheric flow beneath the northern Ordos block, where the shear wave splitting study by Chang et al () reveals a relatively uniform E‐W fast polarization, suggesting the presence of eastward lateral mantle flow at deep depth (>150 km) beneath the Ordos.…”

Section: Discussionsupporting

confidence: 67%

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

Guo

Chen

et al. 2018

JGR Solid Earth

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We constructed a high‐resolution 3‐D Vs model of the northern Ordos block and its surrounding areas by surface wave tomography, which reveals significant intracratonic heterogeneities. In the western Ordos, the lithosphere thickness is ~200 km with shear velocities comparable to the high velocities of other Archean cratons worldwide. However, the lithosphere thins gradually toward the east and Vs drops by 2–3% in the uppermost mantle beneath the eastern Ordos, coincident with the high surface heat flow (~68 mW/m2 in average) there. This observation suggests that the thick, cratonic keel is only locally preserved beneath the western Ordos, and the eastern part of the Ordos seems to undergo local rejuvenation. At greater depths (>180 km), a low‐velocity channel is observed beneath the high‐velocity keel of the Ordos. Beneath the Datong volcanoes, a low‐velocity anomaly is observed, dipping westward with depth and closely following the slope of the lithosphere beneath the northern Ordos. This prominent low velocity is connected with the low‐velocity zone beneath the northern Ordos, which is further connected with the low‐velocity zone beneath the northeastern Tibetan Plateau (NET). We propose that the asthenosphere beneath the NET flows toward the northern Ordos in response to the continuous northward convergence of the Indian‐Eurasian continents, and the asthenosphere flows upward following the eastward thinning lithosphere which leads to decompression partial melting, which migrates upward to feed the Datong volcanoes. The significant variations of the lithospheric thickness of the Ordos block may control the distribution of the asthenospheric flow.

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Section: Discussionsupporting

confidence: 67%

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

Guo

Chen

et al. 2018

JGR Solid Earth

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“…The walls of the strong lithosphere below the western Sichuan Basin have probably hindered the outward growth of the Tibetan Plateau (Bao, Song, & Li, ), constraining its geometry to its current wedge shape. Second, the average magnitude of the delay times from shear wave splitting studies is larger within the plateau than outside the plateau (Chang et al, ; Yu & Chen, ). Shear wave splitting studies have shown that the anisotropic layer is related to a depth range that accommodates the motion of the lithosphere below the Tibetan Plateau (Chang et al, ; Flesch et al, ; Lev et al, ).…”

Section: Discussionmentioning

confidence: 99%

Seismic Tomography of Eastern Tibet: Implications for the Tibetan Plateau Growth

Zhang

et al. 2018

Tectonics

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The eastern region of the Tibetan Plateau and surrounding regions have gentle to moderate topographic gradients, contrasting the steep margins in northern and southern Tibet. The mechanisms for plateau growth in eastern Tibet are uncertain so far. Here we present a new shear wave tomography model of the Tibetan Plateau derived from S wave traveltimes from teleseismic waveforms recorded by the dense ChinArray seismic network. The model reveals the deep structures beneath the eastern region of the Tibetan Plateau and its adjacent regions, showing clear velocity contrast boundaries roughly along the eastern margins of the Tibetan Plateau. We interpret the slow velocity anomalies beneath the Tibetan Plateau as soft lithosphere, which absorbed most of the northeastward push of the Indian Plate, while the fast velocity anomalies beneath the region surrounding the plateau represent craton‐like rigid block roots. The deformation of the soft/weak lithospheric mantle beneath the Tibetan Plateau is constrained by the convergence between the Indian and Eurasian plates, and the framework of the surrounding rigid blocks. We suggest that weak lithosphere deformation (horizontal shortening and vertical stretching) accounts for the plateau growth in eastern Tibet.

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“…The presence of relatively low velocity in upper mantle may account for the mantle flow beneath the WQT [e.g., Guo and Chen, 2017;Li et al, 2016Li et al, , 2017Zheng et al, 2016]. Shear wave splitting measurements also suggested that the asthenosphere mantle flow existed beneath the WQT [e.g., Chang et al, 2017;Yu and Chen, 2016]. The absence of mafic lower crust characterized by high velocity is obvious from our 3-D V s model (Figure 9c) and DSS studies [Vergne et al, 2002;Liu et al, 2006], which could be a consequence of removal of mafic lower crust [Chung et al, 2005;Guo and Chen, 2016].…”

Section: Origin Of Two Crustal Lvzs In the Northern Sgt Southwesternmentioning

confidence: 99%

Three‐dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

Xingchen

Ding

et al. 2017

JGR Solid Earth

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We present a new 3‐D lithospheric Vs model for the NE Tibetan Plateau (NETP) and the western North China Craton (NCC). First, high‐frequency receiver functions (RFs) were inverted using the neighborhood algorithm to estimate the sedimentary structure beneath each station. Then a 3D Vs model with unprecedented resolution was constructed by jointly inverting RFs and Rayleigh wave dispersions. A low‐velocity sedimentary layer with thicknesses varying from 2 to 10 km is present in the Yinchuan‐Hetao graben, Ordos block, and western Alxa block. Velocities from the middle‐lower crust to the uppermost mantle are generally high in the Ordos block and low in the Alxa block, indicating that the Alxa block is not part of the NCC. The thickened crust in southwestern Ordos block and western Alxa block suggests that they have been modified. Two crustal low‐velocity zones (LVZs) were detected beneath the Kunlun Fault (KF) zone and western Qilian Terrane (QLT). The origin of the LVZ beneath the KF zone may be the combined effect of shear heating, localized asthenosphere upwelling, and crustal radioactivity. The LVZ in the western QLT, representing an early stage of the LVZ that has developed in the KF zone, acts as a decollement to decouple the deformation between the upper and lower crust and plays a key role in seismogenesis. We propose that the crustal deformation beneath the NETP is accommodated by a combination of shear motion, thickening of the upper‐middle crust, and removal of lower crust.

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Vertical coherence of deformation in lithosphere in the NE margin of the Tibetan plateau using GPS and shear-wave splitting data

Cited by 91 publications

References 50 publications

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

Seismic Tomography of Eastern Tibet: Implications for the Tibetan Plateau Growth

Three‐dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

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