Morphotectonic Evolution of Selduk Graben in Development Process of Western Anatolian Grabens

Abstract

The Selduk Graben is the name given to the young graben developed in the western tip of the Kuduk Menderes graben. It was a part of the main graben until a strike-slip fault zone cut and displaced it to the southwest during late Quaternary. From this time onward, it has had a semi-independent evolution. In the horsts bordering the graben, metamorphic basement rocks crop out. The fill of the graben consists of alluvium from the Kucuk Menderes River. The Selduk Graben is an asymmetrical graben. The bordering southern horst is more prominent than the northern one, where the normal faults form clear fault steps. Morphologically, the less distinct northern faults may thus be interpreted as antithetic faults, which have developed on the hanging wall of the major listric normal faults of the southern horst. The graben and the bordering horst were cut and displaced by several young strike-slip faults, which have made clear imprints in the morphology, including linear ridges, offset streams, etc. In the development sequence of Western Anatolian grabens, the Selduk Graben is one of the latest ones. The Kuduk Menderes Graben was opened earlier, during the Quaternary. It was located on the horst separating the Buyuk Menderes and Gediz grabens in this period. The elevated horst then collapsed. The Selduk Graben was situated at the western end of the Kuduk Menderes Graben during this period. Later, with the development of NW trending left-lateral strike-slip faults, together with conjugated faults along the coastal region of western Anatolia, the Selcuk Graben was separated from the Kucuk Menderes Graben and has since evolved semi-independently.