Neogene basin development around Söke-Kuşadası (western Anatolia) and its bearing on tectonic development of the Aegean region

Abstract

There is a N–S lying narrow strip of Neogene outcrop between the towns of Kuşadası and Söke in western Anatolia. It contains remnants of successive Neogene graben basins. The first graben began to form under the control of a N40–70°E-trending oblique fault system during the Early Miocene. At the initial phase of the opening coarse clastic rocks were deposited in front of the fault-elevated blocks as scree deposits and fanglomerates. Later the graben advanced into a large lake basin. Towards the end of the Middle Miocene the lacustrine sediments of the Early–Middle Miocene age underwent an approximately N–S compressional deformation and elevated above the lake level, and were partly eroded. During the Late Miocene a new graben basin began to form as a consequence of the development of E–W-trending normal faults, formed under the N–S extensional regime. This graben also turned later into a lake environment. The lake extended far beyond the limits of the fault zones, and covered the entire regions stretching from the south of Bafa Lake in the south to Kuşadası and beyond in the north. Micritic clayey limestones were predominantly deposited in the lake. A severe erosional phase followed the termination of the lake basin. This corresponds to the cessation of the N–S extension. When the N–S extension regenerated during the Pliocene(?)–Pleistocene, the Büyük Menderes graben system began to form. In the western part of the graben, a conjugated pair of oblique faults, the Priene–Sazlı fault and the Kuşadası fault, have formed. The faults having important strike-slip components, bounded a tectonic wedge, which began to move westward into the Aegean Sea region. Major morphological features of the region were formed under the effective control of these fault zones.