Palaeotsunami impact on the ancient harbour site Kyllini (western Peloponnese, Greece) based on a geomorphological multi-proxy approach
Hadler, Hanna; Baika, Kalliopi; Pakkanen, Jari; Evangelistis, Dionysios; Emde, Kurt; Fischer, Peter; Ntageretzis, Konstantin; Röbke, Björn; Willershäuser, Timo; Vött, Andreas
published: Dec 1, 2015
Geoscientific and geoarchaeological studies carried out at the ancient harbour site of Kyllini (western Peloponnese, Greece) revealed distinct evidence of repeated tsunami landfall. Located in the westernmost part of the Peloponnese, the Kyllini harbour site is situated at a narrow stretch of coastal lowland along the northeastern edge of Cape Kyllini. Directly exposed to the Ionian Sea and the Hellenic Trench, the harbour holds a considerably high risk for tsunami events and thus represents a valuable geo- archive for palaeotsunami research. While the inner harbour basin is merely preserved as a near-coast swamp, partially submerged installations like moles, quays, breakwaters and towers clearly define the outer harbour basin. Geoscientific studies carried out at the Kyllini harbour site comprised on-shore and coastal vibracor- ing, sedimentological, geochemical and microfossil analyses of the recovered sediments as well as electri- cal resistivity measurements. The overall geochronological framework is based on radiocarbon dating of biogenic material and age determination of diagnostic ceramic fragments. The stratigraphical record of the harbour site reveals an autochthonous pre-harbour marine embayment on top of Pliocene bedrock. Following a first high-energy impact, a coastal lake was established that was subsequently used as har- bour basin and fortified by man. Following a period of siltation, the harbour sequence is abruptly overlain by a massive layer of coarse grained marine sand, indicating a sudden high-energy impact to the harbour site. Partly preserved as geoarchaeological destruction layer and post-depositionally cemented, the layer forms beachrock-type calcarenitic tsunamites. Our results suggest that the harbour site of Kyllini was affected by two tsunami events. A first event occurred between the late 7th and early 4th cent. BC prior to the harbour foundation while it seems as if at least parts of the harbour basin were later destroyed by a second tsunami event between the 4th and 6th cent. AD.