DOI: 10.1016/j.epsl.2018.06.010
Scopus记录号: 2-s2.0-85049524180
论文题名: Complicated crustal deformation beneath the NE margin of the Tibetan plateau and its adjacent areas revealed by multi-station receiver-function gathering
作者: Xu X. ; Niu F. ; Ding Z. ; Chen Q.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 497 起始页码: 204
结束页码: 216
语种: 英语
英文关键词: ChinaArray
; cluster analysis
; crustal anisotropy
; crustal deformation
; NE Tibet
; receiver function
Scopus关键词: Anisotropy
; Cluster analysis
; Polarization
; Structural geology
; ChinaArray
; Complicated geometry
; Crustal anisotropy
; Crustal deformations
; Crustal thickenings
; Deformation pattern
; Polarization direction
; Receiver functions
; Deformation
英文摘要: We use a multi-station stacking method to analyze receiver function data recorded by a large-scale dense seismic array covering the northeastern (NE) margin of the Tibetan plateau and its adjacent regions to estimate crustal thickness (H), Vp/Vs ratio (κ) and crustal anisotropy (fast polarization direction φ and splitting time τ). For each station of the array, we gathered all the receiver functions recorded by the station and its nearby stations located inside a circle with a radius of 0.5°. We applied the H−κ stacking technique and the joint inversion scheme to a total of 654 station clusters to measure the (H,κ) and (φ τ), respectively. The measured Moho depth varies from a peak value of 67 km beneath the northern-central plateau to 39–45 km beneath the surrounding blocks in the northeast. The front of the depressed Moho beneath the plateau margin exhibits a complicated geometry, which suggests that when the Tibetan plateau encroached upon the surrounding terranes, the front expanded unevenly depending on the strength of the encountering terranes. The thickened crust beneath the margin also has a very low Vp/Vs ratio, indicating that the crust is composed largely of felsic minerals. More than one third of the station clusters (221) have a splitting time significantly larger than 0.2 s. The average splitting times of the 221 measurements is 0.68 s, which is comparable to those measured from the SKS/SKKS (XKS) phases (0.94 s). The fast directions estimated from the Moho Ps and XKS phases recorded by the station clusters within the margin are very similar, and are also approximately parallel to the strikes of major faults, sutures and thrust fronts in the area. The low Vp/Vs ratio, together with the observed fast polarization directions from the Moho Ps and XKS phases, suggests that shortening of the entire lithosphere orthogonal to the compressional direction is likely the main cause for the observed crustal thickening occurring at the margin. We also found that the Moho Ps and XKS recorded by stations inside the western Hetao basin and the Yinchuan basin present very different anisotropy, which may suggest that the crust and mantle beneath the two basins have very different deformation patterns. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109774
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Institute of Geophysics, China Earthquake Administration, Beijing, China; Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, United States; Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; State Key Laboratory of Petroleum Resource and Prospecting, Unconventional Natural Gas Institute, China University of Petroleum at Beijing, Beijing, China
Recommended Citation:
Xu X.,Niu F.,Ding Z.,et al. Complicated crustal deformation beneath the NE margin of the Tibetan plateau and its adjacent areas revealed by multi-station receiver-function gathering[J]. Earth and Planetary Science Letters,2018-01-01,497