Tectonic geomorphology of the Tuz Gölü fault zone: combining morphometrics and structural geology to assess changes in deformation rate and pattern over time

Situated within the interior of the Central Anatolian Plateau (CAP), the 200 km-long Tuzgölü fault zone offers first-order constraints on the timing and pattern of regional deformation and uplift. In this study, we utilize morphometric analysis of 92 catchments along the Tuz Gölü range-front and the parallel, a basinward fault, measuring mountain front sinuosity, basin asymmetry, basin elongation, basin-fault azimuth, hypsometry, river steepness, and knickpoint location, coupled with regional geomorphic observations and longitudinal profile analysis. In addition, we use field and remote mapping to constrain the geometry of two key marker beds, a Mio-Pliocene ignimbrite (5.02 ± 0.2 Ma) and the Pliocene Kışladaǧ limestone (~3.7 Ma), in order to investigate deformation in the footwall of the Tuz Gölü fault zone.

Upwarping of the marker beds indicates greatest cumulative displacement along the central part of the fault zone, suggesting Late Miocene to Early Pliocene extensional reactivation of the Tuzgölü fault with a typical fault displacement profile. However, a change in deformation pattern is marked by transient knickpoints along river channels; morphometric indicators sensitive to shorter timescales, including river steepness, basin elongation, K-ratio, and mountain front sinuosity indicate an overall southeastward increase in footwall uplift rate of the Tuzgölü fault zone which could reflect block rotation or interaction with the Quaternary Hasan Dag volcano. Basin asymmetry and basin-fault azimuth measurements indicate north-northwest tilting of footwall catchments, which may be linked to regional tilting across the CAP interior. Our data suggest the influence of multiple sources of deformation and varying behaviors along the length of the Tuzgölü fault zone, likely due to the interference of crustal and lithospheric-scale processes, such as rotation of crustal blocks, extrusion of the Anatolian microplate, crustal heating due to the presence of the Central Anatolian Volcanic Province (CAVP), gravitational collapse associated with plateau uplift and mantle-driven vertical displacements.