Stratigraphic Revision of the Selendi, Güre, and Uşak Neogene Basins, Western Anatolia

In a re-examination of the Neogene stratigraphy of the Uşak, Güre, and Selendi basins of western Anatolia, western Turkey, the stratigraphic position of the previously defined İnay Group is revised, which was previously considered to be of the Middle Miocene age. Based on mammalian biochronology and stratigraphic relationships, two sequences are identified, separated by conformable/transitional contacts within the former group: the Middle Miocene Güre Group is composed of the Fakılı Formation, characterized by alluvial fan deposits, and the lacustrine Derbent Formation. Radiometric dating of alkaline volcanics laterally associated with Güre Group sediments in the Uşak and Güre basins, and mammalian fossils re-evaluated into the MN5-6 biozones in the Selendi Basin, indicate early Middle Miocene. Considering the stratigraphic relationship with the overlying early Late Miocene İnay Group as redefined, we estimate that the Güre Group was deposited in the Middle Miocene. The İnay Group is characterized by a lateral–vertical transition from alluvial deposits of the Ahmetler Formation to the overlying lacustrine Ulubey Formation. An MN9-10 fauna, containing deinotheres, was found within the latter formation.