Numerical modelling of the deformation of the Iranian plateau

Abstract

The deformation of the Iranian plateau due to the Arabia-Eurasia convergence is studied numerically using the viscous thin-sheet model. The lack of deformation in central Iran and the south Caspian sea is taken into account by including lateral heterogeneities in the lithospheric strength. We present results for models of different rheologies. The results imply that the deformation of the plateau is primarily controlled by the convergence of Arabia and the presence of rigid central Iran and the south Caspian. Deformation reaches to the northern parts at the early stages for many of the rheologies we considered, and crustal thickening takes place over the entire plateau, suggesting that the geometry of the plateau has a dominant effect on the deformation and tends to overshadow the role of rheology. The presence of rigid central Iran can explain the development of the shear zones in eastern and northern Iran. Our results are in good agreement with the observation that in the Zagros the crust is deforming by a creep process, whereas in northern Iran most of the present-day deformation is being accommodated seismically.