DOI: 10.1016/j.tecto.2020.228499
论文题名: Pn uppermost mantle tomography of Central Tibet: Implication for mechanisms of N-S rifts and conjugate faults
作者: Nie S. ; Tian X. ; Liang X. ; Chen Y. ; Xu T.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 788 语种: 英语
中文关键词: Conjugated strike-slip faults
; Indian lithospheric slab
; North-south trending rifts
; Pn velocity
; Tibetan Plateau
英文关键词: Fault slips
; Shear flow
; Strike-slip faults
; Velocity
; Difference method
; Formation mechanism
; Lithospheric slab
; Prominent features
; Tectonic activity
; Uppermost mantle
; Velocity difference
; Velocity structure
; Structural geology
; Cenozoic
; convergence
; extensional tectonics
; fault zone
; seismic data
; seismic source
; seismic velocity
; strike-slip fault
; travel time
; velocity profile
; velocity structure
; China
; Qinghai-Xizang Plateau
英文摘要: The north-south convergence between the Indian and Eurasian continents since Cenozoic has produced the Tibetan plateau, and east-west extension structures have also developed since late Cenozoic. Whether these extensional structures are limited to the crust or extend to the deep lithosphere remains controversial. The uppermost mantle serves as a link between the crust and deep lithosphere, the velocity structure of which provides an important constraint on exploring the mechanism of extensional structures. Based on Pn traveltime data recorded by the SANDWICH network in central Tibet, we use the interstation traveltime difference method to obtain the uppermost mantle velocity structure. Our results show significant velocity differences for the uppermost mantle beneath the conjugated strike-slip faults and rifts, which indicates their different formation mechanisms. The high Pn velocity beneath the conjugated strike-slip faults support an eastward horizontal shear at the base of the upper crust rather than the lower crust has contributed to the development of the conjugated strike-slip faults. The low Pn velocity beneath the rifts in Lhasa may provide evidence for the rifts cutting through the entire crust and reflect the connection between the formation of the rifts and deep tectonic activities. The most prominent features in our results are the low Pn velocity zones beneath the Tangra Yum Co Rift (TYR), the Pumqu-Xianza Rift (PXR) and the zone between the two rifts, and we explain the low Pn velocity as the top of the mantle wedge upon the subducting Indian lithospheric slab. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170668
Appears in Collections: 气候变化与战略
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作者单位: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; University of Chinese Academy of Sciences, Beijing, 100049, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; Institution of Earth Science, Chinese Academy of Science, Beijing, 100029, China
Recommended Citation:
Nie S.,Tian X.,Liang X.,et al. Pn uppermost mantle tomography of Central Tibet: Implication for mechanisms of N-S rifts and conjugate faults[J]. Tectonophysics,2020-01-01,788