Multistage back-arc extension, basin tectonics and normal faulting in the eastern Mediterranean

Geodynamic models have been used to explore the controlling factors for rift and supradetachment basin formations. For the latter, a large (kms) scale (detachment) low angle normal shear zone accommodate the extension and an array of normal faults grow in various geometries and scales. Within the exception of few studies, extension velocities imposed on the lithospheric margins are considered to be constant throughout the model evolution.  Nevertheless, this parameter can vary  based on regional geodynamic factors, for example, during the lifetime of back-arc basins. Here we explore,  how different speed functions can describe the extension rate and influence the tectonic deformation patterns within the lithosphere. ASPECT mantle convection models are used with varying speed functions, such as Vx = constant, linear, logarithmic, and parabolic. Namely,  2D approach provides a simple and focused way to study extension without adding extra complexity where models predict varying speed functions can change stress, the amount of lithosphere thinning, ductile-brittle high strain regions, and the overall deformation patterns. For example, the asymmetric nature of basin architecture can be transformed into symmetric style where both basin margins are controlled by rotating normal faults along horizontal axis. This condition is more favorable with logarithmic change in speed function.  This study offers a simple first step toward understanding characterics of extension and basin tectonics in the eastern Mediterranean where trench retreat in the Aegean has accelerated from 1.7 cm/yr to 3.2 cm/yr during the last approximately 20 Ma.