Millstone quarries along the Mediterranean coast: Chronology, morphological variability and relationships with past sea levels

The coast of the Mediterranean provide several remnants of ancient coastal quarries, which are now useful to study sea level change occurring during the last millennia. Millstones quarries were exploited with same quarrying techniques from rocks like beachrocks, sandstones or similar lithologies, were shaped to be suitable to grind olives, seeds and wheat, to produce oil and flour, or to break apart soft rocks. In this study we integrated historical sources, aerial photography, field surveys and palaeo sea-level modelling to investigate a number of millstones quarries with the aim to asses the intervening sea level change that occurred since the quarries were abandoned. We investigated on their chronology, spatial distribution and spatial relationship to the sea-level. Our results indicate that most of these were carved close to sea level between 1.45 ka and 0.25 ka cal BP, but mainly around 0.45 cal ka BP. Despite the uncertainties associated with the chronology in, we found good agreement between their lowest elevation (between 0.33 m and 0.06 m) and the paleo sea-levels, as predicted by the GIA models.