Development of the Kembos and Eynif structural poljes: Morphotectonic evolution of the Upper Manavgat River basin, central Taurides, Turkey

The evolutionary history of the basin begins with the NW-SE-trending karstic paleovalleys, which first formed on the erosional surfaces that are part of the early and middle Miocene contractional tectonic regime. The tributaries, which developed under the influence of the NW-SE-trending Pliocene strike-slip faults, joined the main trunk of the Manavgat River. Starting at the beginning of the Quaternary, the tensional tectonic regime became prominent, and then a series of graben-horst structures appeared. The Eynif and Kembos poljes formed within two of these structures. The underground capture of surface water occurred in the grabens. The waters of both poljes drain through swallow holes into the Manavgat River and then in to the Mediterranean Sea. The regional uplift rates (the downcutting rates) are as follows: 0.36 mm/y in the late Miocene (Tortonian-Messinian), 0.06 mm/y in the Pliocene, and 0.18 mm/y in the Quaternary periods, which are based on the geopmorphic data obtained from high erosional surfaces and the Manavgat River valley. The average downcutting/uplift rate is 0.18 mm/y in this region.