Abstract
AbstractThe mechanism of crustal deformation and the development of large offset strike‐slip faults during continental collision, such as the India‐Eurasia zone, remains poorly understood. Previous mechanical models were simplified which are either (quasi‐)2‐D approximations or made the a priori assumption that the rheology of the lithosphere was either purely viscous (distributed deformation) or purely localized. Here we present three‐dimensional visco‐elasto‐plastic thermo‐mechanical simulations, which can produce both distributed and highly localized deformation, to investigate crustal deformation during continental indentation. Our results show that large‐scale shear zones develop as a result of frictional plasticity, which have many similarities with observed shear zones. Yet localized deformation requires both a strong upper crust (>1022 Pa·s) and a moderately weak middle/lower crust (~1020 Pa·s) in Tibet. The brittle shear zones in our models develop low viscosity zones directly beneath them, consistent with geological observations of exhumed faults, and geophysical observations across active faults.
Highlights
The Himalayan‐Tibetan orogen is a spectacular example of continent‐continent collision, which resulted in pervasive crustal deformation in Asia (Yin & Harrison, 2000)
Several endmember models have been proposed for lithospheric deformation in Tibet and surrounding regions, including an extrusion model suggesting that deformation is primarily localized along large‐scale strike‐slip faults and thrust zones (Replumaz & Tapponnier, 2003; Tapponnier et al, 1982, 2001); thin viscous sheet models suggesting that shortening is distributed and vertically coherent within the lithosphere (England & McKenzie, 1982; Houseman & England, 1986); and channel flow models implying that a thickened weak channel develops in the lower crust which spreads the deformation front outward from the plateau (Clark & Royden, 2000; Royden et al, 1997)
The model geometry is simplified, these models are useful to understand the dynamics of crustal deformation during Himalayan‐Tibetan orogeny
Summary
The Himalayan‐Tibetan orogen is a spectacular example of continent‐continent collision, which resulted in pervasive crustal deformation in Asia (Yin & Harrison, 2000). Recent numerical models mostly focus on the development of topography (Chen et al, 2017; Lechmann et al, 2011; Pusok & Kaus, 2015) and subduction dynamics (Capitanio, 2020; Li et al, 2013; Replumaz et al, 2016; Sternai et al, 2014), emphasizing the effect of variable lateral and vertical lithosphere strength across multiple terranes (Bischoff & Flesch, 2018; Chen et al, 2017; Huangfu et al, 2018) Such models provide valuable insights in the dynamics of the lithospheric deformation, but the limited resolution of these models inhibits resolving strongly localized deformation within the crust in a three‐dimensional (3‐D) framework.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
