The Crucial Link Between Sedimentation and the Activity of the Pull - Apart Basins Revealed by Models and Observations Over Aegean-Anatolia

Abstract

Large scale strike slip (transform or transfer) faults are associated with releasing bends that evolve into deep, asymmetric pull-apart basins/rhomb grabens. While kinematics and the geometric characteristics of these basins are well-understood in the context of regional stress field, within the exception of few studies, geological and geophysical constraints are not often compared and contrasted against geodynamic models. Here we investigate the tectonic controls on the formation of several pull apart basins in the Aegean-Anatolia region through integrating high resolution geodynamic models into a large number of geological (structural) data. Specifically, we investigate the evolution of transtensional basins using high-resolution 3D geodynamic models (ASPECT) coupled with a landscape evolution code (FastScape). Model results show that the development of the transtentional basins over million years are function of several primary factors, including the interaction between pace of sedimentation, and the faulting (shear zone formation). In some cases, especially in the Kocaçay basin of the western Anatolia extended terrane, shallow dipping detachment faults control the supra detachment basin formation where continuous sedimentation of the Miocene deposits (1300 m thick) possibly kept the basin active. Overall, the sediment loading amplifies crustal thinning and this explains the evolution of pull-aparts of the North Anatolian fault, for example Erzincan basin in the east where thick alluvial and lacustrine sedimentary cover is not a passive feature rather control the driver of the basin’s structural persistence.