to Poisson et al, there was likely a canyon, as there still is over by the Düden and Karaman mouths near Antalya, but this canyon has since been filled in by Quaternary deposition from the Aksu River. Evolution The pre-Miocene basement primarily consisted of the Bey Dağlari platform, surrounded by the Antalya Nappes, and covered by a thin layer of Paleogene sedimentary deposition. This formed "an eroded flat surface [that] covered a large area in SW Turkey". Beginning in the Late Oligocene, and continuing through the Burdigalian, rising sea levels caused a marine transgression in the area. The shallow marine Karabayir Limestones were deposited in the north and west, forming a large platform around what is now the Aksu Basin. Meanwhile, to the south, a molassic basin was formed; this was the beginning of the Antalya Basin as a whole. Miocene By the Early Miocene, a "right-lateral transform fault plate boundary" had formed between the Cyprus Trench and the Isparta Angle. This led to the creation of "a hybrid, terrestrial-shallow marine accommodation space" on the eastern side of the Isparta Angle, where sediments from the Antalya Complex further east were deposited. In the Middle Miocene ( 16-11 MYA), the Aksu Basin was formed as a graben cutting through the Karabayir platform. Meanwhile, the surrounding continental areas were being pushed upward; erosion from these areas provided a lot of sediment that was poured into the emerging Aksu Basin. According to Kaya, this was especially the case with the rapidly uplifting Antalya Complex to the east; it "provided the topographic gradient and gravitational potential energy for the necessary fluvial erosion and transport for sediment supply". Poisson et al instead highlight the basin's northern and western margins, where a series of fan deltas at prehistoric river mouths left thick sediment deposits – for example, the present-day Kapıkaya and Kargı fan deltas. The Aksu and Karpuzçay Formations were deposited during this period in what Kaya describes as "fluvial, deltaic to beach environments". Coral reefs fringed the coastline. These reefs lay on a "warm, well-aerated shallow marine shelf" in the photic zone. The low species diversity – primarily colonies of Porites and Tarbaellastraea – may indicate a "stressed" environment. The shore was "medium-high wave energy-dominated", and the climate was temperate to subtropical. The presence of coral fossils among the fan delta deposits is likely from periods when sudden sea level increase left the deltas underwater.