On the Significance of Small-scale and Short-lived Air Escape Structures for the Destruction of Primary Sedimentary Laminations in the Çolakı Beach Deposits, Gulf of Antalya, Turkey (Eastern Mediterranean)

Çolakı beach is a 4 km long coastal depositional system on the Mediterranean coast of southern Turkey. It has been accumulating at the foot of Taurus tectonic belt since the late Pleistocene. The beach deposits are composed of fine-grained sands with no significant longshore changes in granulometry and mineralogy. In addition, the sequence of beach deposits is characterized by a homogenous internal appearance due to the lack of preserved primary sedimentary structures. On the foreshore, air-escape structures comprising small tubes, 5–30 mm in length and 0•5–3 mm in width are extensively formed along the upper swash zone during the backwash phase of wave action. When the next wave swashes across the beach, the former structures are destroyed, at the same time producing conditions for the creation of new ones. The escape structures destroy the original sedimentary lamination. It is thus proposed that the homogenous internal appearance of the older beach deposits has been produced by the same mechanism.