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Tectonic geomorphology and Plio-Quaternary structural evolution of the Tuzgolu fault zone, Turkey: Implications for deformation in the interior of the Central Anatolian Plateau

Krystopowicz, Neil J.
Schoenbohm, Lindsay M.
Rimando, Jeremy
Brocard, Gilles
Rojay, Fuat Bora
Situated within the interior of the Central Anatolian Plateau (Turkey), the 200-km-long Tuzgolu extensional fault zone offers first-order constraints on the timing and pattern of regional deformation and uplift. In this study, we analyze the morphometrics of catchments along the Tuzgolti range-front fault and the parallel, basinward Hamzali fault using a variety of measured morphometric indicators 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, the Pliocene Kizilkaya ignimbrite and Kisladag limestone, in order to investigate deformation in the footwall of the Tuzgolu fault zone. The marker beds form a broad arch along the footwall of the fault, with greatest cumulative displacement along the central part of the fault zone, suggesting early Pliocene extensional reactivation of the Tuzgolu fault with a typical fault-displacement profile. However, a change in deformation pattern is marked by transient knick-points along river channels; morphometric indicators sensitive to shorter (1-3 Ma) time scales, including river steepness, basin elongation, and mountain front sinuosity, indicate an overall southeastward increase in footwall uplift rate of the Tuzgolu fault zone, which could reflect block rotation or interaction with the 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 Central Anatolian Plateau interior. Varying patterns of spatial and temporal deformation along the length of the Tuzgolu fault zone are likely due to the interference of crustal- and lithospheric-scale processes, such as rotation of crustal blocks, extrusion of the Anatolian microplate, crustal heating, gravitational collapse associated with plateau uplift, and mantle-driven vertical displacements.