Archaeological topographical survey and marine geophysical investigation at ancient and medieval harbour of Kyllini/Glarentza (NW Peloponnese, Greece)

The present study presents the preliminary results of the interdisciplinary topographical, underwater archaeological and marine geophysical survey conducted in NW Peloponnese, Greece, in order to shed light on the ancient harbour site and Crusader’s port of Kyllini/Glarentza. Built by the Franks in the 13th century, it developed as one of the major ports during the Crusaders’ period in NW Greece. The medieval harbour installations were built on the ancient port of Kyllini of the Classical period. It was an important naval base and harbour serving the sanctuary of Olympia.
   The Kyllene Harbour Project is a joint project of the Finnish Archaeological Institute at Athens and the Department of Underwater Antiquities (Ministry of Culture). It is conducted in collaboration with the Departament of History, Archaeology and Cultural Resources Management, University of the Peloponnese, and the Laboratory of Marine Geology and Physical Oceanography, Department of Geology, University of Patras.
   The remains of harbour installations of the medieval port are very extensive, including an inner and an outer harbour, demonstrating that the flourishing Crusaders’ port consisted of different sections. One of the principal purposes of the interdisciplinary study is a detailed survey of the submerged remains in order to comprehend the layout of the harbour and to reconstruct the coastline for the different construction phases of the port (Classical and Medieval).
   The coastal area under study is located at the northern end of the promontory of the Chlemoutsi headland, at the northwestern coast of the Peloponnese. Geologically, the area is a segment of a large coastal sandy plain with barrier lagoons, the Elis coastal plain, extending along the western coast of the Peloponnese. The coastal formations consist of Holocene alluvial deposits made up of colluvium, fluvio-torrential sediments, coastal dunes and beach material. At present, the shoreline of the Elis coastal plain is controlled by transgression and erosion, but in the past the coastal evolution had been controlled by the eustatic sea-level signal, local tectonic instability and diapirism.
   The archaeological survey concentrated on the precise 3D topographical investigation using total stations to measure details of the harbour remains and shallow-water features. The marine geophysical study has, so far, employed a 3.5 kHz sub-bottom profiler system in order to examine the seafloor bathymetry and the recent sub-bottom stratigraphy of the coastal area. A side-scan sonar system was employed in order to examine the seafloor surface composition and the existence of potential targets on the seafloor. Furthermore, an Overhauser magnetometer survey was conducted in order to investigate the magnetic signature of the seafloor, especially in the area where the harbour remains are concentrated.
   In the field campaigns of 2007-2009, the marine geophysical instrumentation carried out a dense grid of parallel and vertical lines to the shoreline, whilst the topographic survey of the underwater remains recorded more than 30 000 points which give detailed picture of the archaeological remains and their current setting. The water depths recorded by the echosounder and the shallow-water topographical survey were combined to present the total bathymetry of the area. All the collected data were georeferenced and displayed in a G.I.S. environment.
   The synthesis of the collected data revealed the aerial distribution of the submerged harbour remains and the seafloor morphology related to the different ancient port installations. Furthermore, it revealed targets of potential archaeological interest. Finally, the study demonstrated that the use of remote sensing techniques in conjunction with detailed archaeological and topographical survey in shallow-water coastal sites could be an effective methodological approach for the study of submerged ancient ports and coastal installations in the eastern Mediterranean.