Pre-Roman U-Th datings of an aqueduct near ancient Lebedos (Aegean Region, Türkiye)

In the vicinity of the ancient city of Lebedos, known as one of the twelve Ionian cities, located south of İzmir in W. Anatolia (Türkiye), the NE-SW-trending active Tuzla Fault zone is characterized by numerous hot springs and associated travertine-type carbonate deposits (sinter). Among these, the active Doğanbey bath features an approximately 560 m-long hot water aqueduct, called the “Roman Aqueduct”. This structure is distinct from the well-known Roman (Byzantine) ruins (Karakoç bath) in the area in terms of its materials and construction techniques. Despite the absence of detailed archaeological or geochronological studies in this region, the Doğanbey bath and aqueduct have conventionally been attributed to the Roman era.

The trough and sidewalls of the Doğanbey aqueduct are covered with a 5–25 cm-thick, laminated sinter crust, formed by the flow of hot water. Each sinter lamina comprises radial structures of calcite and/or aragonite, resembling feather-like shrub structures. This study employs the U-Th chronometry to determine the age of sinter layers covering the Doğanbey bath aqueduct. Two layers from a single sinter sample of the ancient Doğanbey aqueduct yielded U-Th ages of 2717 ± 106 and 2528 ± 106 years (BP). These dates indicate a pre-Roman phase of settlement in the Lebedos area, a finding documented for the first time through this study.