Formation of Rifts in Central Tibet: Insight From <i>P</i> Wave Radial Anisotropy

Zhang, Heng; Li, Yunyue Elita; Zhao, Dapeng; Zhao, Junmeng; Liu, Hongbing

doi:10.1029/2018jb015801

Cited by 10 publications

(5 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A magnetic and gravity study revealed that the whole WSB is underlain by a rifted continental crust (Ferraccioli et al, 2009). The rifting can raise the temperatures and change the anisotropic features not only in the crust but also in the upper mantle (Savage , 1999 ; Zhang et al, 2018). At the western edge of the WSB (near the Belgica Highlands), SWS results reveal different fast directions from those in the NTAM (Barklage et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Upper Mantle Deformation of the Terror Rift and Northern Transantarctic Mountains in Antarctica: Insight From P Wave Anisotropic Tomography

Zhang

Zhao

et al. 2020

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

A large number of teleseismic traveltime data are used to determine the first P-wave radial anisotropy tomography beneath the Terror Rift, the northern Transantarctic Mountains (NTAM) and the Wilkes Subglacial Basin in Antarctica. Our results show that variations of radial anisotropy occur in both horizontal and vertical directions. In the NTAM, a high-velocity zone with positive radial anisotropy is revealed at shallower depths, which reflects the lithospheric deformation pattern formed during the Ross Orogeny. In contrast, negative radial anisotropy appears at depths >200 km under the NTAM, which is caused by the characterization of olivine fabric rather than foundering lithosphere. Beneath the western Wilkes Subglacial Basin, a two-layer lithosphere exists that contains rift-induced cracks. To the east of the NTAM, asthenospheric upwelling occurs at shallow depths beneath the Terror Rift. Then the upwelling asthenosphere flows northward to Mount Melbourne and southward to Mount Erebus.

show abstract

Section: Discussionmentioning

confidence: 99%

Upper Mantle Deformation of the Terror Rift and Northern Transantarctic Mountains in Antarctica: Insight From P Wave Anisotropic Tomography

Zhang

Zhao

et al. 2020

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…In contrast, the HVZ with a negative RAN feature in the northern part of the profile (H1' in Figure 3a) reflects that the northern part of the ILM was affected by the previously attached Tethyan oceanic slab (H. Zhang et al, 2018) because the negative RAN anomaly is generally related to vertical shear or deformation. Another interpretation of the HVZ is foundering ILM.…”

Section: Different Deformation Patterns Within the Ilmmentioning

confidence: 97%

“…Another controversial issue is whether the formation of the Tibetan rifts (or grabens) is a crustal process or related to the whole lithosphere or the asthenosphere (Yin & Harrison, 2000). Most of the seismic studies prefer the latter case, including slab tearing in the ILM (X. F. Liang et al., 2016), internal deformation of the ILM and ELM (H. Zhang et al., 2018), and upwelling asthenosphere (Ren & Shen, 2008). However, such seismic evidence depends on the limited data recorded by seismic arrays in central and eastern Tibet.…”

Section: Introductionmentioning

confidence: 99%

Upper Mantle Heterogeneity and Radial Anisotropy Beneath the Western Tibetan Plateau

Zhang

Zhao

et al. 2021

Tectonics

Self Cite

View full text Add to dashboard Cite

It is generally considered that the tectonic evolution of the Tibetan Plateau is influenced by continental collision (e.g., Yin & Harrison, 2000), but many fundamental issues are still not resolved. For example, what happens in the advancing Indian lithospheric mantle (ILM), and what are the responses of the Eurasian lithospheric mantle (ELM)? Zhou and Murphy (2005) suggested that the ILM has subducted beneath the whole Tibet, whereas Kind et al. (2002) detected the ELM in northern Tibet. In recent years, some studies have revealed significant east-west variations of the northward advancing ILM (e.g., J. T. Li & Song, 2018; X. F. Liang et al., 2016). A subvertical high-velocity zone has been revealed at depths of 100-400 km by seismic tomography (Tilmann et al., 2003), and it was interpreted as a downwelling lithosphere in eastern Abstract P-wave radial anisotropy (RAN) tomography of the upper mantle beneath the western Tibetan Plateau is determined using teleseismic arrival time data recorded at 71 temporal seismic stations of the ANTILOPE-I and Y2 arrays, which reveals a complex deformation pattern in the upper mantle. A high-velocity anomaly with prominent positive RAN is visible to the south of 31°N, which may reflect the underthrusting Indian lithospheric mantle (ILM). Further north, another high-velocity zone appears at depths >200 km, which is possibly related to the foundering ILM, or the northward advancing ILM affected by previously attached Tethyan oceanic slab. Considering the continuity of the high-velocity zones and similarity of the RAN anomalies, we suggest that there is no slab tearing or breakoff at present beneath western Tibet. To the north of 31°N, E-W trending variations of velocity and RAN at shallow depths (<150 km) suggest that small-scale convection occurs between 79°E and 81°E, whereas the residue of the Eurasian lithospheric mantle is located in the eastern side. We deem that the formation of the Ya-Re Rift and Puran Graben was caused by variations of the lithospheric thickness instead of slab tearing or asthenospheric upwelling, considering locations of the rift and the graben and our present results. Plain Language Summary Our study region, the Tibetan Plateau, is a hot and ideal region to study the mechanisms of the convergence between continental plates. It is generally considered that the Tibetan Plateau is a product of convergence between the Indian and Eurasian plates, but some fundamental issues are still not resolved. For example, what happens in the northward advancing Indian lithospheric mantle (ILM), and what are the responses of the Eurasian lithospheric mantle (ELM)? Because of the extremely hard environment in the western Tibetan Plateau, seismic tomography is an effective way to illuminate the underground structure by processing earthquake waveforms recorded at seismograph stations. Although the interpretations of velocity anomalies are consistent, the anisotropy features result in different conclusions. Our results reveal both horizontal and vertical variations in the ...

show abstract

“…Many previous workers have studied the crustal and upper mantle structure under western Tibet with receiver functions, tomography, and shear wave splitting (Li et al, 2008;Nabelek et al, 2009;Chen et al, 2010;Hung et al, 2010;Xu et al, 2011;Basuyau et al, 2013;Zhang et al, 2012Zhang et al, , 2015Zhang et al, , 2018Liang et al, 2016;Wang et al, 2019). However, most of these studies utilize the seismic data recorded by Hi-CLIMB Project from southern to central Tibet plateau, whereas little research has been conducted in the northern Tibet.…”

Section: Introductionmentioning

confidence: 99%

Tomographic Imaging of the India‐Asia Plate Collisional Tectonics and Mantle Upwelling Beneath Western Tibet

Zheng

et al. 2020

Acta Geologica Sinica (Eng)

View full text Add to dashboard Cite

To better understand the lithosphere mantle collision tectonics between the India plate and Asia plate, we determine three dimensional P wave velocity structure beneath western Tibet using 27,439 arrival times from 2,174 teleseismic events recorded by 182 stations of Hi‐CLIMB Project and 16 stations in the north of Hi‐CLMB. Our tomographic images show the velocity structure significantly difference beneath northern and southern Qiangtang, which can further prove that the Longmu Co‐Shuanghu ophiolitic belt is a significant tectonic boundary fault zone. There are two prominent high velocity anomalies and two prominent low velocity anomalies in our images. One obvious high velocity anomalies subduct beneath the Tibet at the long distance near 34°N, whereas it is broke off by an obvious low velocity anomaly under the IYS. We interpret them as northward subducting Indian lithosphere mantle and the low velocity anomanly under IYS likely reflects mantle material upwelling triggered by tearing of the northward subduction Indian lithosphere. The other prominent high velocity anomaly was imaged at a depth from 50 km to 200 km horizontal and up to the northern Qiangtang with its southern edge extending to about 34°N through Hoh Xil block. We infer it as the southward subducting Asia lithosphere mantle. The other widely low velocity anomaly beneath the Qiangtang block lies in the gap between the frontier of India plate and Asia plate, where is the channel of mantle material upwelling.

show abstract

Formation of Rifts in Central Tibet: Insight From P Wave Radial Anisotropy

Cited by 10 publications

References 58 publications

Upper Mantle Deformation of the Terror Rift and Northern Transantarctic Mountains in Antarctica: Insight From P Wave Anisotropic Tomography

Upper Mantle Deformation of the Terror Rift and Northern Transantarctic Mountains in Antarctica: Insight From P Wave Anisotropic Tomography

Upper Mantle Heterogeneity and Radial Anisotropy Beneath the Western Tibetan Plateau

Tomographic Imaging of the India‐Asia Plate Collisional Tectonics and Mantle Upwelling Beneath Western Tibet

Contact Info

Product

Resources

About