NUMERICAL MODELING OF THE DEFORMATION OF THE IRANIAN PLATEAU

The deformation of the Iranian plateau due to the Arabia-Eurasia conve rgence 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 theologies. The results imply that the deformation of the plateau is primarily control led by the convergence of Arabia and the presence of rigid central Ira n 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 g eometry of the plateau has a dominant effect on the deformation and te nds to overshadow the role of theology. The presence of rigid central Iran can explain the development of the shear zones in eastern and nor thern Iran. Our results are in good agreement with the observation tha t in the Zagros the crust is deforming by a creep process, whereas in northern Iran most of the present-day deformation is being accommodate d seismically.