Tectonic activity and tectonic geomorphology of the Acigöl Graben

The Acıgöl Graben is located in southwestern Turkey, an extensional domain related to slab rollback in the subducting African lithosphere. This is a 50 km long and 10 km wide neotectonic depression with a NE-SW orientation that veers into an E-W trend in its southern part. The Maymundağı and Acıgöl Quaternary faults control the NW and SE margins of the basin, respectively. This study analyses the graben-bounding faults and demonstrates their late Quaternary activity based on morpho-stratigraphic evidence, supported by Optically Stimulated Luminescence (OSL) dating. The Acıgöl Fault on the SW margin juxtaposes Mesozoic carbonate rocks against Quaternary deposits. The uplifted range, with a local relief of around 1 km, shows geomorphic evidence of deep-seated gravitational slope deformation (e.g., uphill-facing scarps, ridge-top depressions). The southern sector displays E-W intra-basin faults that have compartmentalized the basin floor into a series of fault-angle depressions with fluvio-lacustrine sub-basins in the downthrown blocks and southward tilted surfaces in the upthrown blocks. Numerical ages indicate a maximum age of 24 ka for the youngest displacement event on these faults. In the northwestern part, Maymundağı Fault juxtaposes Oligocene conglomerates against Quaternary alluvial fan deposits. The fault displays two parallel fault strands where the basin attains an E-W trend. The northern fault strand is the master basin-bounding fault, whereas the southern one is an intra-basin fault that offsets and oversteepened alluvial fan surfaces. OSL ages from deformed deposits indicate fault activity younger than 3 ka.