Archaeological remains as sea level change markers: a review

The Mediterranean Sea constitutes a unique basin from an historical and archaeological point of view, as it has been a privileged way of communication for thousands of years for the people that dwelled on its shores. Their passage has left many traces on the seabeds in the areas where the ancient commercial routes passed, and remains of structures where moorings, havens or dwellings existed. Some of these structures, nowadays submerged, offer interesting indications aiding the reconstruction of the ancient coastlines. This contribution aims to examine recent work in coastal geo-archaeology, targeting both (1) gathering and discussion of the data, particularly those pertaining to the Italian coasts; and (2) commentary on the methodological debate and verification of the possibility of a protocol that may contain unequivocal referring elements. To investigate the archaeological evidence currently underwater because of the relative sea level variations (harbour infrastructures, fishponds, villae maritimae, caves – nymphaei, private or public buildings or town quarters, pre- and protohistorical villages, quarries, caves, etc.), a clear and more coherent methodological assumption may be needed. The archaeological interpretation must initially establish the maritime and/or harbour nature and vocation of the site, determine its typology and specific usage, analyze the elements of its building techniques (that reveal themselves as meaningful markers of height or depth at the time of building) and its ‘‘functional’’ elements (the measure of the emerged part with respect to the average sea level), and point out the time of construction, its chronological range of usage/ frequentation, the dynamics of its abandonment/destruction/obliteration. The evaluation of both the height and functional depth to the mean sea level depends on the typology of the archaeological evidence, its use and the local tide amplitudes. The surface of a pier surely has a functional elevation different from that of a haulage area or a platea or a pavement.