SEEKING ANCIENT GREEKS AND ROMANS BENEATH MEDITERRANEAN WAVES: PROBLEM-SOLVING AT SUBMERGED SITES BY GEOPHYSICAL AND SEDIMENTARY CORE SURVEYS

Geophysical and sediment core surveys, essential for the study of submerged archaeological sites, are an integral part of our exploration off Italy and Egypt. These techniques supplement diver exploration by detailing the deeper-lying subbottom to solve subsea archaeological problems: (1) definition of the geographic and tectonic configuration and nature (petrology, litho- and biofacies) of once subaerially-exposed substrates on which sites were built; (2) interpretation of landscape evolution prior to, during and following human occupation; and (3) detection of natural events and human activity that lead to either progressive or sudden destruction of population centers.

At Kaulonia and Locri (~800 to 300 BCE), Magna Graecia sites in southern Italy, our goal is to locate and define the configuration of ports and/or ship-landing sites near walled towns where heavy cargo could be transferred to shore. At Kaulonia, numerous sections of columns, dated to ~450 BCE, are scattered over the seafloor (~5 m depth) about 150 to 300 m distant from shore. This distribution was attributed to rapid subsidence of a former headland, Cape Stilo, by fault lowering. However, closely-spaced high-resolution seismic lines show continuity of strata that dip gently from shore to inner shelf. While sudden vertical fault-drop of a former prominent cape at this locality is now ruled out, the possibility of a destructive seaward slide remains. Additionally, cores serve to define sediment facies and faunal assemblages, parameters helpful in locating the former buried Assi river mouth and wetland settings that once may have been used for ship landing.

Dated cores, along with seismic, side-scan and other geophysical data, collected in Alexandria’s eastern and western harbors and in Abu Qir Bay, Egypt, indicate that Greek and younger structures at these localities were also destroyed and submerged by natural events. Subsidence occurred progressively over time in some instances, and quite suddenly in others. Destructive events include flood and sediment failure near the Nile’s Canopic mouth in Abu Qir Bay, and earthquake, tsunami and massive sediment failure in Alexandria harbors. These geoscience techniques serve to compile time-slice maps of ancient sites, thus assisting archaeologists and historians to refine their interpretations.