Topography associated with crustal flow in continental collisions, with application to Tibet

R. Bendick, D. Mckenzie, J. Etienne

Research output: Contribution to journalArticlepeer-review

Abstract

Collision between an undeformable indenter and a viscous region generates isostatically compensated topography by solid-state flow. We model this process numerically, using a finite element scheme. The slope, amplitude and symmetry of the topographic signal depend on the indenter size and the Argand number of the viscous region, a dimensionless ratio of gravitational body forces to viscous forces. When applied to convergent continental settings, these scaling rules provide estimates of the position of an indenter at depth and the mechanical properties of the viscous region, especially effective viscosity. In Tibet, forward modelling suggests that some elevated, low relief topography within the northern plateau may be attributed to lower crustal flow, stimulated by a crustal indenter, possibly Indian lithosphere. The best-fit model constrains the northernmost limit of this indenter to 33.7°N and the maximum effective viscosity of Eurasian middle and lower crust to 1 × 1020 ± 0.3 × 1020Pa s.

Original languageEnglish
Pages (from-to)375-385
Number of pages11
JournalGeophysical Journal International
Volume175
Issue number1
DOIs
StatePublished - 2008

Keywords

  • Asia
  • Continental tectonics: Compressional
  • Dynamics of lithosphere and mantle
  • Numerical solutions

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