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Lower Crustal Rheology Controls the Development of Large Offset Strike‐Slip Faults During the Himalayan‐Tibetan Orogeny
Author(s) -
Yang Jianfeng,
Kaus Boris J. P.,
Li Yang,
Leloup Philippe Hervé,
Popov Anton A.,
Lu Gang,
Wang Kun,
Zhao Liang
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl089435
Subject(s) - geology , shear zone , lithosphere , crust , seismology , orogeny , continental crust , shear (geology) , brittleness , rheology , petrology , deformation (meteorology) , continental collision , geophysics , tectonics , oceanography , physics , materials science , composite material , thermodynamics
The 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 (>10 22 Pa·s) and a moderately weak middle/lower crust (~10 20 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.