Quaternary tensional neotectonics of the southwestern flank of the Isparta Angle, Antalya, Türkiye

The pre-Quaternary paleotectonic period is represented by polyphase compressional deformation in the southwestern flank and core of the Isparta Angle (IA) in SW Türkiye. This is evidenced by folds with approximately N–S-trending axes, east- and west-facing thrust, and reverse faults, which originated from the emplacement of Late Paleocene Antalya and the Langhian Lycian nappes and were reactivated during the Aksu phases of thrusting in the Middle–Late Pliocene. In contrast, since the onset of the Quaternary, the area has been dominated by a tensional neotectonic regime, marked by E–W extension and associated with normal faulting. This shift is demonstrated by the kinematic analysis of slip-plane data from the fresh fault slickensides, syn-sedimentary growth faults within the Quaternary basin fill, and the focal mechanism solutions from recent earthquakes. The uniform uplift rate has been approximately 0.4 mm/year since the beginning of the Quaternary on a local scale. This value corresponds to the total downcutting of the Burhan and Düden streams.