ALTERNATIVE CENOZOIC EXHUMATION HISTORY OF THE KAZDAG CORE COMPLEX, WESTERN TURKEY

Kazdag core complex is located on the north of Edremit gulf. The core complex consists of high-grade metamorphic rocks and granitoid intrusions. Detailed field observations and microstructural studies indicate that two different detachment faults play important role on the exhumation of Kazdag core complex.

The first detachment fault, called Selale detachment in the literature, separate from rocks of the Cetmi melange to metamorphic and granitoid rocks and has dominant top- to-the N sense of shearing. The second detachment fault, named as Yesilyurt detachment in this study, is a low angle normal fault at the present. It juxtaposes Lower Miocene Kucukkuyu formation to Cetmi melange. The shear sense kinematic indicators display top-to-the south sense of shearing. This detachment was probably high angle normal fault during the opening of E-W trending Edremit graben and control the deposition of Kucukkuyu formation and then it is rotated to the present low angle position. The basal conglomerates of Kucukkuyu formation contain fragments originated from metamorphic rock of the core complex and rocks of the Cetmi melange, which suggest that the Kazdag massif was already on the surface during the deposition of Kucukkuyu formation. The last tectonic episode is characterised by the strike-slip faults postdating the Yesilyurt detachment fault.

As a result, it can be speculated that the Selale detachment could be related structurally to the Datca-Kale main breakaway fault and its northern continuation Simav detachment. If it is true, the ophiolitic rocks constituting the upper plate attributed to Izmir-Ankara suture zone behave as a rootless unit in the extensional tectonic history of western Turkey.

Keywords: Kazdag, Core complex, Aegean region, Edremit graben, detachment fault