Crustal and Upper Mantle Velocity Structure of SE Tibet From Joint Inversion of Rayleigh Wave Phase Velocity and Teleseismic Body Wave Data

Yang，Xiaozhou1,2; Luo，Yinhe1,3; Jiang，Chengxin2; Yang，Yingjie4; Niu，Fenglin5; Li，Guoliang6

2023-07-01

10.1029/2022JB026162

Journal of Geophysical Research: Solid Earth   影响因子和分区

2169-9313

2169-9356

Since the continental collision between the Indian and Eurasian plates began about 50 Ma ago, southeastern Tibet (SET) has undergone complex tectonic deformation. In this study, we investigate fine scale structural features of the crustal and upper mantle depths (<250 km) beneath SET, which hold important clues to understanding the dynamic processes related to this collision. A 3D shear velocity model is constructed through jointly inverting Rayleigh wave phase velocity and teleseismic body wave data from more than 650 stations. Our 3D model identifies three independent low-velocity zones (LVZs) in the mid-lower crust with unprecedented details. More specifically, we observe a prominent LVZ beneath the North Chuan-Dian Block, which is well separated from another LVZ beneath the Tengchong volcano in the south. This LVZ beneath the volcano represents a focused magma reservoir in the crust whose origin is potentially linked to the mantle upwelling associated with the eastward subduction of the Indian plate. The third LVZ, observed around the Xiaojiang Fault, likely represents a separated and mechanically weak layer in the mid-lower crust due to the combined effects of regional crustal thickening under the southeastward plateau expansion, mantle upwelling, and shear heating of strike-slip faults. In the upper mantle, we observe strong velocity reductions both in localized areas beneath the Tibetan Plateau and the broad region south of 26°N. These low velocity anomalies are sitting above high velocity anomalies at deeper depths, suggesting their association with lithospheric thickening and delamination processes.

body wave waveform joint inversion lithospheric delamination mid-lower crustal low-velocity zone southeastern Tibet surface wave phase velocity

SCI

英语

NI论文

通讯

National Natural Science Foundation of China[41874058];National Natural Science Foundation of China[42074055];

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:001031971400001

AMER GEOPHYSICAL UNION

GEOSCIENCES

2-s2.0-85165488290

Scopus

1.Hubei Subsurface Multi-scale Imaging Key Laboratory,School of Geophysics and Geomatics,China University of Geosciences,Wuhan,China
2.Research School of Earth Sciences,Australian National University,Canberra,Australia
3.State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan,China
4.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,China
5.Department of Earth,Environmental and Planetary Sciences,Rice University,Houston,United States
6.Department of Earth Sciences and Southern California Earthquake Center,University of Southern California,Los Angeles,United States

Yang，Xiaozhou,Luo，Yinhe,Jiang，Chengxin,et al. Crustal and Upper Mantle Velocity Structure of SE Tibet From Joint Inversion of Rayleigh Wave Phase Velocity and Teleseismic Body Wave Data[J]. Journal of Geophysical Research: Solid Earth,2023,128(7).

Yang，Xiaozhou,Luo，Yinhe,Jiang，Chengxin,Yang，Yingjie,Niu，Fenglin,&Li，Guoliang.(2023).Crustal and Upper Mantle Velocity Structure of SE Tibet From Joint Inversion of Rayleigh Wave Phase Velocity and Teleseismic Body Wave Data.Journal of Geophysical Research: Solid Earth,128(7).

Yang，Xiaozhou,et al."Crustal and Upper Mantle Velocity Structure of SE Tibet From Joint Inversion of Rayleigh Wave Phase Velocity and Teleseismic Body Wave Data".Journal of Geophysical Research: Solid Earth 128.7(2023).