A MICROSTRUCTURAL STUDY OF THE FOOTWALL ROCKS OF BABADAG FAULT ZONE, SOUTHWESTERN MARGIN OF THE DENIZLI BASIN, WESTERN ANATOLIA, TURKEY

Post-collisional extension in the Aegean region caused the exhumation of the Menderes Massif of western Anatolia, Turkey. The central part of the Massif is exhumed by two oppositely dipping detachment surfaces, namely the Alasehir Detachment Surface to the north and the Buyuk Menderes Detachment to the south. The Babadag fault zone is located along the eastern part of the Central Menderes Massif. It trends NE-SW and separates ductily to brittely deformed metamorphic rocks in its footwall from the brittely deformed sedimentary rocks of the Denizli Basin in its hanging wall. It has a low angle of dip in the vicinity of the town of Babadag. But, it splays into high angle normal faults in the Denizli area.

We have conducted microstructural analysis of the footwall fault rocks along the splays of the Babadag fault zone to the southwest of the Denizli basin. In the footwall, we have found many ductile shear-sense indicators such as ó-type porphyroclasts and C'-type bands indicating top to the north normal movement. The footwall rocks also contain top to the north brittle shear sense indicators such as cataclastic flow and synthetic microfaults overprinting the ductile shear sense indicators. These observations suggest to us that the prominent movement along the Babadag fault zone and its high-angle splays is top to the north.

The timing of the this top to the north normal movement, however, is in question. The Babadag fault zone contains Upper Miocene and Plio-Quaternary sedimentary rocks of the Denizli Basin in its hanging wall. Therefore, it may have been formed in Late Miocene. The potential also exists to date monazite in rock thin sections from the fault rocks with an ion microprobe to determine the exact age of Babadag fault zone and its splays controlling the southwestern margin of the Denizli Basin.