DOI: 10.1016/j.tecto.2021.228835
论文题名: Deep electrical resistivity structure across the Gyaring Co Fault in Central Tibet revealed by magnetotelluric data and its implication
作者: Xue S. ; Chen Y. ; Liang H. ; Li X. ; Liang X. ; Ma X. ; Lu Z. ; Bai D. ; Yan Y.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 809 语种: 英语
中文关键词: Conjugate strike-slip fault
; E-W extension
; Magnetotellurics (MT)
; Rift
; Tibet
英文关键词: Cobalt
; Electric conductivity
; Geodynamics
; Magnetotellurics
; Plates (structural components)
; Strike-slip faults
; Apparent resistivity
; Conductive layer
; Deformation feature
; Electrical resistivity structures
; Geodynamic modeling
; Magnetotelluric data
; Resistivity structure
; Threedimensional (3-d)
; Fault slips
; deformation
; electrical resistivity
; Eurasian plate
; extensional tectonics
; fault zone
; formation mechanism
; geodynamics
; Indian plate
; lithospheric structure
; lower crust
; magnetotelluric method
; rift zone
; strike-slip fault
; upper mantle
; China
; Qinghai-Xizang Plateau
英文摘要: As one of the most prominent deformation features on Tibetan plateau, a series of N-S systematic rifts and V-shaped conjugate strike-slip faults are well developed in central-southern Tibet. However the mechanism for the formation of the rifts and conjugate strike-slip faults is still controversial. An east-west trending magnetotelluric (MT) array has been operated across the Gyaring Co Fault (GCF) at the northern end of the Xainza-Dingjye Rift (XDR) in Lhasa block. Three-dimensional (3-D) inversions are employed to image lithospheric resistivity structure. Combined with the previous north-south MT 3-D inversion result, electrical resistivity models reveal obvious conductive layer in the mid-to-lower crust beneath the XDR and apparent resistivity change in the vicinity of the GCF. The calculated depth-integrated conductivity shows that the weak mid-to-lower crust (~30 km- ~ 60 km) characterized by high conductance (≥ ~10,000 S) and melt fraction of ~5–13%, is mainly distributed between the Indus-Yarlung suture (IYS) and the GCF, whereas the relatively rigid crust characterized by low conductance (≤ ~2000 S) and melt fraction of ~2–4% appears to the northeast of the GCF. The weak mid-to-lower crust in southern Tibet and the abrupt difference in the resistivity characteristics of the mid-to-lower crust in the vicinity of the GCF, suggest the formation of the rifts in Lhasa block is closely associated with the weak mid-to-lower crust. Taken together with the upper mantle seismic features, the weak mid-to-lower crust is believed to be attributed to the underplated Indian plate. An alternative geodynamic model is presented to respond to the eastward extrusion during the ongoing N-S convergence between the Indian and Eurasian plates, that the rigid crust in central Tibet is sandwiched by the weak mid-to-lower crust in southern and northern Tibet, and the rifts form above the weak mid-to-lower crust, whereas the conjugate strike-slip faults develop on the rigid crust in central Tibet. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170929
Appears in Collections: 气候变化与战略
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作者单位: Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China; State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China; School of Earth Science and Geological Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
Recommended Citation:
Xue S.,Chen Y.,Liang H.,et al. Deep electrical resistivity structure across the Gyaring Co Fault in Central Tibet revealed by magnetotelluric data and its implication[J]. Tectonophysics,2021-01-01,809