PALEOSHORELINE RECONSTRUCTION AND UNDERWATER ARCHAEOLOGICAL POTENTIAL OF LIMAN TEPE: A LONG-OCCUPIED COASTAL PREHISTORIC SITE IN WESTERN TURKEY

Liman Tepe is a long-occupied coastal prehistoric site near Izmir in western Anatolia. Land archaeological excavations have uncovered Chalcolithic settlement layers and pottery evidence of Neolithic occupation. Previous shoreline reconstructions using land core data indicate a Holocene marine transgression ~1 km inland of the site (ca. 4000 BCE). The shoreline positions during the Middle Neolithic to Early Chalcolithic (ca. 6500-4000 BCE) were not established but presumed to lie seaward of the modern shoreline. To better resolve the paleoshoreline positions and relative sea level (RSL) change, a detailed multi-proxy study was conducted on 20 marine sediment cores extracted in 5-15 m water depth. Shoreline positions were determined by back-stripping of de-compacted sediment thickness from a digital bathymetric model.

Marine coring revealed a sequence of organic-rich marine muds and sandy shoreface deposits overlying a compact clay layer containing abundant weathered bedrock (trachyte) fragments and AMS ¹⁴C dated to > 6000 cal BCE. The basal clay contained no foraminifera, scant thecamoebians and had elevated Ti/Ca, K and Fe, indicating a regolith formed by sub-aerial weathering of volcanic bedrock. The clay was overlain by a sandy gravel with abundant shell fragments and a foram assemblage indicative of a shallow shoreface environment. The marine-terrestrial interface marks a transgressive surface, which was correlated onshore in land core data and used to reconstruct paleoshoreline positions. During the Middle Neolithic (ca. 6500 BCE; RSL = -14 m) the shoreline was ~300 m seaward and present-day Karantina Island was a broad coastal headland. By 4800 BCE (Early Chalcolithic) the coastline had transgressed landward ~800 m and Liman Tepe was small coastal promontory separated from the mainland by shallow wetlands. After 4000 BCE, sea level rise decelerated and the shoreline prograded rapidly by barrier accretion.

The underwater mapping identified two new areas of archeological potential: 1) the sheltered embayment to the east of Liman Tepe may have served as a Chalcolithic/ Bronze Age mooring area and has potential for shipwrecks, 2) the submerged paleoshorelines and promontory to the west of Karantina Island (water depths 10-14 m) are areas with high potential for discovery of underwater Neolithic sites.