Rifting and Subsidence Following Lithospheric Removal in the Western Anatolia Back-arc Region

Abstract

The western Anatolia-Aegean region is dominated by back-arc extensional deformation with significant lithospheric thinning, southward sweeping volcanism, and metamorphism. While several geodynamic models (e.g., slab retreat, orogenic collapse) have been postulated to explain the cause of extension and subsidence, they have only considered each of these mechanisms in isolation. Numerical experiments are used to test whether the observed anomalous topography and syn-convergent extension in western Anatolia are driven through the combined effects of post-lithospheric removal and retreating subduction. Model results suggest that post-lithospheric removal in the extending back-arc can concurrently depress the surface and produce high rate of extension/thinning (β > 2), in which the results are in good fit with the regional observational constraints. There is also notable extension/subsidence due to the slab retreat and high temperature back-arc even if the mantle lithosphere has not been removed. Models with only slab retreat results in minor surface elevation lowering and crustal thinning/extension in the back-arc region. These findings can explain the > 1.5 km elevation increase from Cretean sea to western Anatolia although the difference in crustal thickness is small, based on receiver function studies.

AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014