Apatite fission-track thermochronology of the Western Pontides (NW Turkey)

The results of apatite fission-track analyses of the Western Pontides of NW Turkey point to three discrete episodes of Cenozoic exhumation correlatable with major supraregional tectonic events. (1) Paleocene–early Eocene exhumation reflected the closure of the ˙Izmir–Ankara ocean. (2) Late Eocene–earliest Oligocene exhumation was the result of renewed tectonic activity along the ˙Izmir–Ankara suture. (3) Late Oligocene–early Miocene exhumation recorded the onset of northern Aegean extension. Samples collected north and south of the tectonic contact between the two terranes forming the Western Pontides (i.e. ˙Istanbul and Sakarya terranes) record the same cooling events, suggesting that such terranes were amalgamated in pre-Cenozoic times.