During the Mesozoic (the age of Dinosaurs, 250ma – 67ma) the Anatolide-Taurides were the site of an extensive carbonate platform, (similar to the Caribbean today) , where deposition of several thousand meters thick shallow marine carbonates took place. Robertson (page 100) assumes that these units represent part of the Neotethyan oceanic basin which opened in the Triassic (250 to 200 ma) followed by complete closure in late Paleogene time (50 – 25ma). The Lycian Nappes sit on top of this carbonate platform and were created by the closure of the Neotethys along the Izmir – Ankara Suture. The exposed rocks around Göcek are dominated by the Lycian Mélange and the Lycian Peridotite.
The major thrust sheets of the Lycean Nappes. Taken from Robertson (page 101)
A mélange is a body of rock characterized by a lack of continuous bedding and the inclusion of fragments of rock of all sizes, contained in a fine-grained deformed matrix. The mélange typically consists of a jumble of large blocks of varied lithologies. Large-scale melanges formed in active continental margin settings generally consist of altered oceanic crustal material and blocks of continental slope sediments in a sheared mudstone matrix.
Peridotite is a dense (3.3gm/cm³), coarse-grained igneous rock rich in magnesium and pale green in colour. It is the dominant material of the upper part of the earth’s mantle and forms the bulk of oceanic crust. Oceanic crust is created at mid-ocean ridges when continents move apart. When plates collide the dense oceanic material is generally subducted under the lighter continental crust. The Lycean Nappes are derived from oceanic crust scraped off the subducted plate to form an accretionary prism. This is the process which produced the highly contorted pattern seen in the rocks around Göcek.
The term Nappe indicates a formation which has been pushed at least 2km over the underlying rocks that were formed in place (autochthon). The Lycean Nappes are thought to have been thrust many 10s for km. In some areas the Lycean Nappes sit on top of coastal sediments formed in the Miocene (25 – 5ma).