Constraining Deformation History and Activity Along the Tuz Gölü Fault Zone: Implications for Uplift in the Interior of the Central Anatolian Plateau

Wednesday, 17 December 2014: 5:15 PM
Neil J Krystopowicz and Lindsay M Schoenbohm, Univ. of Toronto Mississauga, Department of Chemical and Physical Sciences, Toronto, ON, Canada
The 200 km long, northwest-striking Tuz Gölü fault zone, located along the eastern margin of the Tuz Gölü basin, represents an integral part of the Central Anatolian Plateau (CAP). Late Miocene to recent uplift of the northern and southern margins of the CAP are relatively well understood, however the uplift history of the plateau interior remains poorly constrained. Situated within the interior of the CAP, the Tuz Gölü fault zone may offer first-order constraints on the timing and pattern of regional uplift.

The Tuz Gölü fault zone may have developed as early as Maastrichtian times. Whether it initially formed as an extensional or compressional structure remains contentious, as the fault system has likely undergone multiple episodes of reactivation. In this study, we use a combination of paleostress and morpho-tectonic analysis to further delineate the geologic history and evolution of the Tuz Gölü fault zone. Paleostress analysis of fault and joint data show two principal phases of deformation – pre-upper Miocene compression and late Miocene to Quaternary extension, supporting a regional changeover from compression to extension in Anatolia during the late Miocene that broadly coincides with the onset of regional uplift. Additionally, we conducted a morphometric analysis of over 300 drainage basins along the range-front, measuring mountain front sinuosity, basin asymmetry, basin elongation, basin-fault azimuth, and hypsometry. Overall, morphometric indices provide evidence of a southeastward increase in footwall uplift rate of the Tuz Gölü fault zone that could be the result of a regional uplift gradient, block rotations, or a combination of these processes. Basin asymmetry and basin-fault azimuth indicate north-northwest tilting of catchments which may be linked to regional tilting associated with late Miocene to recent uplift of the CAP. Lastly, our morphometric data support migration of deformation into the Tuz Gölü basin interior. Our regional observations could reflect uplift in the CAP interior, crustal thinning associated with slab-tear propagation in the subducting African lithosphere, or elevated extension and isostatic rebound in the Tuz Gölü footwall due to the presence of a detachment system that is active in the uppermost crust and above which basin fill is being uplifted and eroded.