Oblique Deformation in Central Turkey: Fault Interaction and River Incision at the Intersection of the Tuz Gölü and Central Anatolian Fault Zones

Wednesday, 17 December 2014
Lindsay M Schoenbohm1, Bulent Tokay2, Neil J Krystopowicz1, Mark Higgins1, Bora Rojay2 and Gilles Y Brocard3, (1)University of Toronto, Department of Earth Sciences, Toronto, ON, Canada, (2)Middle East Technical University, Department of Geological Engineering, Ankara, Turkey, (3)Univ of Pennsylvania, Philadelphia, PA, United States
Although much of the deformation associated with Arabia-Eurasia collision and Aegean extension is expressed by westward translation of Central Anatolia along the North Anatolian and East Anatolian fault zones, important deformation also takes place in the interior. Major interior faults include the NE-SW striking, left-lateral Central Anatolian fault zone (CAFZ), which splays from the NAFZ, and the NW-SE striking, right-lateral Tuz Gölü fault zone (TGFZ). We examine fault kinematics and river incision in the triangular region bound by the TGFZ to the SW, the CAFZ to the E and the Salanda graben to the N, in order to document fault interaction and landscape development where these fault systems intersect. We document deformation in the footwall of the Tuz Gölü fault, recorded by the warping of ignimbrite and lacustrine units. We investigate the Salanda fault, which displaces a 1.23 Ma basalt flow by 40 m. Paleostress analysis indicates two deformation phases with maximum strain nearly parallel (191 for extension; 183 for shortening).The Salanda fault reactivates older mylonite near the town of Karaburna. We map faults in the interior of this region, including the N-S striking Derinkuyu fault and the newly identified Derbentbaşi fault. The Derinkuyu fault has been inactive since emplacement of a lava dome at its north end. The Derbentbaşi fault offsets lacustrine limestones and older ignimbrites in a right-lateral, west-side down sense prior to regional river incision. Pliocene lacustrine carbonates are largely confined to the hanging walls and footwalls of the TGFZ and the Yeşilhisar strand of the CAFZ; these deposits are deeply incised and can be used to constrain the pattern and timing of river incision. Along the Salanda graben, the Kızılırmak River has incised the surrounding region to a depth of 350 m. Our data suggest a complicated interaction between the TGFZ and CAFZ, with faulting distributed on multiple, obliquely striking structures, few of which remain active today. We also identify an important role for pre-existing weaknesses in governing the location and orientation of faults in this system. We find structural control on the location and/or preservation of lacustrine sedimentation, and evidence for significant recent incision due to regional uplift and local disruption along fault systems.