Exhumation history of the Aydın range and the role of the Büyük Menderes detachment system during bivergent extension of the central Menderes Massif, western Turkey

Nilius N-P, Glotzbach C, Wölfler A, Hampel A, Akal C, Heineke C, Hetzel R

Abstract

The central Menderes Massif (western Turkey) is a prominent example of symmetrical exhumation of a core complex. It comprises the Bozdaǧ and Aydın ranges, which represent the footwalls of the north-dipping Gediz detachment and the south-dipping Büyük Menderes detachment, respectively. In contrast to the Gediz detachment, the role of the Büyük Menderes detachment during Late Cenozoic extension and exhumation of the central Menderes Massif is less well resolved. Here, we present results from structural and geological mapping as well as new fission-track and (U–Th)/He data to show that two low-angle normal faults contributed to the exhumation of the Aydın range. Our data indicate that the sustained activity of the Büyük Menderes detachment since the early Miocene is followed by the onset of faulting along the previously unrecognized Demirhan detachment, which is situated in the hanging wall of the Büyük Menderes detachment, in the latest Miocene/ Pliocene. Thermokinematic modelling of cooling ages from the footwalls of the Büyük Menderes and Demirhan detachments yielded exhumation rates of c. 0.5 and c. 0.4 km/Ma, respectively. Apatite fission track ages from the Demirhan detachment indicate a slip rate of c. 2 km/Ma during the Pliocene. High-angle normal faulting along the modern Büyük Menderes graben commenced in the Quaternary.