Büyük Menderes Granbeni'nin Rolling Hinge (Yuvarlanan Reze) Modelinde Supra-Detachment (Sıyrılma Üstü) Havzadan Rift Havzasına Evrimi

Abstract

Two types of basins developed in the Western Anatolian extensional tectonic system during the Miocene- Quaternary interval, supra-detachment and rift basins, in the form of a rolling-hinge mechanism. In this study, stratigraphic and structural data on the presence of a rolling-hinge model in the area between Buharkent-Buldan on the northern edge of the Buyuk Menderes Graben are presented for the first time and the geological evolution of the graben is discussed. In the light of obtained field data, the Miocene-Quaternary sequences deposited on the northern edge of the Buyuk Menderes Graben were evaluated under 4 main sedimentary packages, which are separated from each other by angular and/or intrabasinal unconformities. These are the Lower-Middle Miocene (1st Package)  and the Middle-Upper Miocene (2nd Package) which were deposited in the supra-detachment basin, and the Plio-  Quaternary 3rd and 4th packages formed in the rift basin. The structural elements that provide the basin formation and deformation of the region are the Miocene Buyuk Menderes Detachment Fault, the Pio-Quaternary Gokdere Fault, and the Holocene Buharkent Fault Segment that cuts the youngest graben basin-fill located in the most eastern part of the Buyuk Menderes Fault System. The main fault contacts of the supra-detachment basins characterizing the Miocene period are represented by a structural boundary of gneisses and schists belonging to the Menderes Massif, which is a relict of the effective compressional tectonic products of the Eocene–Oligocene interval. Due to the effectiveness of low-angle faults in the Menderes Massif until the end of Pliocene, a high rate of extension occurred; because of this, the crust thickness was reduced. As a result of cooling of the crust during Quaternary, the supra-detachment basin system was replaced by a rift system and the Menderes Massif was divided into blocks along the high-angle boundary faults of the rift basin. Field observations and kinematic analysis reveal that tectonic structures on the northern margin of the Buyuk Menderes Graben evolved from low-angle to high-angle normal faulting, and were rejuvenated southward parallel to the basin propagation in a rolling-hinge model. Thus, the basin formation also evolved from being supra-detachment to the rift type.