Structural Elements and Neogene Lithostratigraphy of the Manavgat Basin (Antalya, Turkey)

Abstract

The Tauride fold-thrusts belt has formed under similar to S-N convergence between the Africa and Eurasian plates since Cretaceous time. This movement also resulted in the development of the complex tectonic structure known as the Isparta Angle. In the Neogene period, the western and central Taurides and the inner part of the Isparta Angle became overlain by marine sedimentary basins (Antalya Basin Complex). The Manavgat Basin is one of these marine basins, and unconformably rests on the Tauride in the north. Basically, the Manavgat Basin has a sedimentation thickness of more than 1 km from the Early Miocene to Pliocene. Hence, it is expected to keep the geological records regarding the crustal deformation, besides the lithostratigraphic records during this time. Lithostratgraphically, seven basic units have been identified in the Manavgat Basin. These are, in line with previous studies; 1) Tepekli Formation (Burdigalian-E. Langhian), 2) Oymapinar Limestone (G. Burdigalian-Langhian), 3) Cakallar Breccia (Langhian), 4) Geceleme Formation (G. Langhian-Serravalian), 5) Karpuzcay Formation (G. Langhian-Tortonian), 6) Pliocene units (Yenimahalle and Kursunlu formations), and 7) Belkis Conglomerate (Quaternary). Biosamples were collected from two different measured sections of the Karpuzcay Formation, and the age of the formation was determined. These show that the Karpuzcay Formation was deposited in a deep marine outer neriticbathyal environment from the Late Langhian to Tortonian. In addition to lithostratigraphic features, structural elements forming the Manavgat Basin were also studied, and the Tortonian aged Cardakkoy Fault was described for the first time in this study. As a result, the presence of two different tectonic regimes in the region was determined. Accordingly, the Manavgat Basin developed under the influence of an extensional tectonic regime before the Tortonian, and of a compressional system during the post-Tortonian. This study indicated that N-S directional convergence between Eurasia and Africa and the kinematics of the fragmented subducted plate under the Isparta Angle should be reevaluated based on these paleostress phases.