Tectonic implications of fluvial incision and pediment deformation at the northern margin of the Central Anatolian Plateau based on multiple cosmogenic nuclides

摘要

[1] We document Quaternary fluvial incision driven by fault-controlled surface deformation in the inverted intermontane Gokirmak Basin in the Central Pontide mountains along the northern margin of the Central Anatolian Plateau. In-situ-produced ~(10)Be, ~(21)Ne, and ~(36)Cl concentrations from gravel-covered fluvial terraces and pediment surfaces along the trunk stream of the basin (the Gokirmak River) yield model exposure ages ranging from 7 ± 1 ka to 346 ± 45 ka and average fluvial incision rates over the past ～350 ka of 0.28±0.01 mm a"1. Similarities between river incision rates and coastal uplift rates at the Black Sea coast suggest that regional uplift is responsible for the river incision. Model exposure ages of deformed pediment surfaces along tributaries of the trunk stream range from 60 ± 5 ka to 110 ± 10 ka, demonstrating that the thrust faults responsible for pediment deformation were active after those times and were likely active earlier as well as explaining the topographic relief of the region. Together, our data demonstrate cumulative incision that is linked to active internal shortening and uplift of～0.3 mm a~(-1) in the Central Pontide orogenic wedge, which may ultimately contribute to the lateral growth of the northern Anatolian Plateau.