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

The study area is the upper Manavgat River basin. It is located in the western part of the central Taurides. Two significant geomorphic features of this basin are the Kembos and Eynif structural poljes. This study focuses on the tectonic impacts on the development of poljes and the morphotectonic evolutionary history of the study region. The data were obtained through a detailed mapping of the faults, rocks, and geomorphic features. 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: 0.36mm/y in the late Miocene (Tortonian-Messinian), 0.06mm/y in the Pliocene, and 0.18mm/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 0.18mm/y in this region. •Kembos and Eynif structural poljes formed in Quaternary grabens under the control of the tensional neotectonic regime.•Waters of the poljes are drained to Manavgat River by underground conduits.•Middle Miocene erosional surfaces and Miocene paleovalleys are located on mountains.•NW-SE trending tributaries of the Manavgat River developed during Pliocene.•Manavgat River incised its valley up to 1229m after Upper Tortonian.