Late Cenozoic Sedimentary Evolution of the Antalya Basin, Southern Turkey

Abstract

The Late Cenozoic Antalya Basin developed unconformably on a foundered basement comprising Mesozoic autochthonous carbonate platform(s) overthrust by the Lycian Nappes, the Antalya Nappes and the Alanya Massif metamorphics within the Isparta Angle, southern Turkey. The present configuration of the basin consists of three distinct parts, referred herein as the Aksu, Koprucay and Manavgat sub-basins, respectively, which are divided by the north-south-trending Kirkkavak Fault and the westward-verging Aksu Thrust. The Miocene fill of each sub-basin is characterized by thick accumulations of non-marine to marine clastics with locally developed coralgal reefs and reefal shelf carbonates. Based on lithostratigraphic and chronostratigraphic considerations, integrated with previously established data, the Miocene fill of the Antalya Basin is reorganized into nine formations and twelve members. A total of nineteen facies have been distinguished within this stratigraphic framework. The stratigraphic organization and the time and space relationships of these facies indicate contrasting styles of sedimentation characterized by several facies associations representing deposition in colluvial and alluvial fan/fan delta with coralgal reefs, reefal shallow carbonate shelf, base of fault-controlled fore reef slope and clastic open marine shelf environments in the tectonically active sub-basins. The coralgal reefs, which occur as small, isolated patch reefs developed on progradational alluvial fan/fan delta conglomerates, and the reefal shelf carbonates represent small to large scale, transgressive-regressive cycles which are closely associated with the complex interaction between sporadic influxes of coarse terrigeneous clastics derived from the tectonically active basin margins and/or related to the eustatic sea level changes during Late Burdigalian-Langhian and Late Tortonian-Messinian times. With regard to structural history, the Antalya Neogene basins exhibit contrasting behaviour according to their position within the Isparta Angle. West of Antalya, the Lycian Basin is linked to the eastwards advance of the overlying Lycian Nappes up to the Burdigalian; in the centre of the Isparta Angle, the Aksu and Koprucay sub-basins are younger (Serravalian-Tortonian) and exhibit intense deformation, reflecting west-directed compressional -events of Late Miocene to Lower Pliocene age. In contrast, the Manavgat sub-basin situated further east is only weakly deformed, and even farther east, the Ermenek and Mut basins are almost undeformed. Thus the evolution of the Neogene Antalya basins highlights the fundamental structural asymmetry of the Isparta Angle.