Coastline evolution, submerged landscape, and island occupation: Preliminary insight on Pleistocene-Holocene coastal environments of south-eastern Sicily

Sicily, the largest island in the Mediterranean and the closest to mainland Europe, holds some of the earliest uncontroversial evidence in the region of sustained island occupation by humans, dating back to ∼16.5 thousand years ago (ka). Using archival studies as well as dive-based and coastal fieldwork, this study provides initial insights into the diversity of submerged and coastal Pleistocene–Holocene landscapes off and on the coast of south-eastern Sicily. New archaeological and geomorphological data demonstrate the continued importance of Sicily in understanding early human uses of islands and nearshore resources well into the Pleistocene. With underwater and coastal archaeological surveys in the Siracusa and Ragusa areas, combined with innovative citizen science, and museum research, and sedimentary analysis, we have identified five key archives: 1) Pleistocene and Holocene archaeological and geological sea-level markers, confirming the quasi-stable tectonic conditions of the SE area of Sicily; 2) Coastal and partially submerged caves containing Middle and Late Pleistocene fauna and geomorphological features, re-identified after their 19th-century discovery, offering valuable data on faunal transitions and environmental changes; 3) Submerged caves and shoreline caverns (at 1 to 25 m water depth) that are possible deposits containing fauna and anthropogenic remains; 4) Submerged landscapes with clay-rich deposits that may represent paleosols or terrestrial Pleistocene-Holocene deposits, possibly associated with prehistoric human occupation of the island; and 5) Three concentrations of Pleistocene-Holocene flint materials (two reworked assemblages of anthropogenically modified flint artifacts in Ognina and Portopalo di Capo Passero —possibly dating to the Neolithic/Mesolithic period — and a concentration of unworked flint nodules at Punta delle Formiche representing an unrecognized natural source of raw material for tool manufacture). These archives provide new data on the island's carrying capacity, the diversity andavailability of coastal resources,and sea-level changes since the Last Glacial Maximum (26.5–19 cal ka BP).