|
Journal: |
Journal of Geophysical Research 2018 No.5
clicks:163 |
|
Title:
|
|
|
Author:
|
Zhigang Li1 , Peizhen Zhang1 , Wenjun Zheng1 , Dong Jia2 , Judith Hubbard3 , Rafael Almeida3 , Chuang Sun1 , Xuhua Shi3 , and Tao Li |
|
Adress: |
Guangdong Provincial Key Lab of Geodynamics and Geohazards, School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou, China |
|
Abstract:
|
Eastern Tibet is an important example of oblique convergence and associated strain
partitioning, as suggested by recent 2-D and 3-D structural interpretations, yet the nature and evolution of
oblique strain partitioning of this region remain poorly known. Here we use seismic reflection profiles,
borehole data, and field investigations in the Longmen Shan piedmont to determine the subsurface
structural architecture, and we observe several nearly N-S striking thrusts and reactivation of NE striking
preexisting faults. We interpret that this behavior is due to a regional principal compressional stress oriented
in the E-W direction, oblique to the NE striking Longmen Shan. Using the records of fault activity and related
Late Pliocene and Quaternary foreland sediments and growth strata, as well as the coseismic rupture of the
2008 Mw 7.9 Wenchuan earthquake, we demonstrate that the Longmen Shan has experienced E-W crustal
shortening and oblique motion since ~5–2 Ma. We present two strain partitioning models arising from
oblique thrusting in eastern Tibet and suggest that the eastward extrusion from Tibet is mainly
accommodated on the strike-slip Longriba fault and the dip-slip Longmen Shan-Min Shan fault zones. These
results enhance our understanding of the tectonic relationship between the Songpan-Ganzi terrane and the
Sichuan basin and provide additional constraints for studies of the geodynamic response of eastern Tibet to
the ongoing India-Eurasia collision. |
|
Comment: |
|
|
|
|
