The archaeological evidence of sea level change in the Mediterranean: guidelines and reappraisals

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Late Quaternary sea-level change and early human societies in the central and eastern Mediterranean Basin : an interdisciplinary review

This article reviews key data and debates focused on relative sea-level changes since the Last Interglacial (approximately the last 132,000 years) in the Mediterranean Basin, and their implications for past human populations. Geological and geomorphological landscape studies are critical to archaeology. Coastal regions provide a wide range of resources to the populations that inhabit them. Coastal landscapes are increasingly the focus of scholarly discussions from the earliest exploitation of littoral resources and early hominin cognition, to the inundation of the earliest permanently settled fishing villages and eventually, formative centres of urbanisation. In the Mediterranean, these would become hubs of maritime transportation that gave rise to the roots of modern seaborne trade. As such, this article represents an original review of both the geo-scientific and archaeological data that specifically relate to sea-level changes and resulting impacts on both physical and cultural landscapes from the Palaeolithic until the emergence of the Classical periods. Our review highlights that the interdisciplinary links between coastal archaeology, geomorphology and sea-level changes are important to explain environmental impacts on coastal human societies and human migration. We review geological indicators of sea level and outline how archaeological features are commonly used as proxies for measuring past sea levels, both gradual changes and catastrophic events. We argue that coastal archaeologists should, as a part of their analyses, incorporate important sea-level concepts, such as indicative meaning. The interpretation of the indicative meaning of Roman fishtanks, for example, plays a critical role in reconstructions of late Holocene Mediterranean sea levels. We identify avenues for future work, which include the consideration of glacial isostatic adjustment (GIA) in addition to coastal tectonics to explain vertical movements of coastlines, more research on Palaeolithic island colonisation, broadening of Palaeolithic studies to include materials from the entire coastal landscape and not just coastal resources, a focus on rescue of archaeological sites under threat by coastal change, and expansion of underwater archaeological explorations in combination with submarine geomorphology. This article presents a collaborative synthesis of data, some of which have been collected and analysed by the authors, as the MEDFLOOD (MEDiterranean sea-level change and projection for future FLOODing) community, and highlights key sites, data, concepts and ongoing debates

Palaeogeography of Ancient Lasaia (SE Crete, Greece)

The remains of the Hellenistic-Roman harbour-town of Lasaia are situated in southeastern Crete on a headland at the NE end of the bay of Kaloi Limenes, while at a short distance from the shore lies the island of Traphos. The application of a geoarchaeological method allowed us to reconstruct the palaeogeography of the coast and track the evolution of the ancient harbour of Lasaia from the Minoan palatial period to Hellenistic-Roman times to the 17th century AD.The palaeogeography of the seafront of ancient Lasaia followed the relative sea level changes that occurred during the last 4,000 years along the coast of central and eastern Crete: from a tied island connected to the mainland by a strip of land when the sea level was at 4.15 ± 0.30 m between ca. 1900 BC and ca. 1600 BC, and 2.50 ± 0.20 m bmsl between ca. 1600 BC and ca. 1200 BC, to a low promontory jutting out into the sea within a short distance from the coast of Traphos when the sea level was at 1.20 ± 0.10 m bmsl between ca. 1200 BC and AD 1604, and finally to a narrow shore opposite the island, when the sea level rose to 0.55 ± 0.05 m bmsl during the AD 1604 earthquake, which remained there for a significant period of time within the last 400 years.During the Minoan palatial period, an artificial outer breakwater at the SW end of Traphos Island appears to have formed a protected harbour basin. In Hellenistic-Roman times, the outer breakwater had been submerged and an inner breakwater was constructed, leaving a channel between it and the island that allowed mariners to pass from the western to the eastern basin depending on the weather. In the early 17th c., the island was isolated from the mainland and provided shelter for Cretan refugees.Les vestiges de la ville portuaire antique de Lasaia sont situés dans le sud-est de la Crète sur un promontoire à l'extrémité nord-est de la baie de Kaloi Limenes, à proximité de l'île de Traphos. Nous avons pu reconstruire la paléogéographie de la côte et reconstituer l'évolution de l'ancien port de Lasaia de la période minoenne jusqu'au 17e siècle après J.-C. La paléogéographie du front de mer a suivi les changements relatifs du niveau de la mer qui se sont produits au cours des 4 000 dernières années. Le niveau de la mer était à -4,15 ± 0,30 m vers 1900-1600 avant J.-C., -2,50 ± 0,20 m vers 1600-1200 ans avant J.-C., -1,20 ± 0,10 m entre vers 1200 av. J.-C. et 1604 après J.-C., et enfin vers -0,55 ± 0,05 m lors du tremblement de terre de 1604 après J.-C. Pendant la période minoenne, un brise-lames à l'extrémité sud-ouest de l'île Traphos semble avoir protégé un bassin portuaire. À l'époque hellénistique et romaine, le brise-lames a été submergé et un deuxième brise-lames intérieur a été construit, permettant la circulation des navires du bassin ouest au bassin oriental en fonction de la météorologie marine. Au début du xviie siècle, l'île était finalement séparée du continent, offrant un abri à des réfugiés crétois

Past and Future Impacts of the Relative Sea Level Rise on the Seafront of Ancient Delos (Cyclades, Greece) and Flooding Scenarios by 2150

Sea level rise due to global warming is a continuing and, disappointingly, accelerating process which has already affected and will further impact coastal lowlands and the social and economic activities in these areas. Delos Island, situated in the middle of the Cyclades in the Aegean Sea, was considered the most sacred of all islands in ancient Greek culture and was a trading hub for the entire eastern Mediterranean. Uninhabited since the 7th century AD, and consistently the focus of research and touristic attention, the island is designated as an archaeological site and inscribed on the UNESCO World Heritage List. Previous studies on the relative sea level (rsl) changes suggest a steadily rising rsl during the last 6300 years, starting from a sea level of −4.80 ± 0.20 m in the Late Neolithic. The seafront of the ancient city of Delos is subject to the effects of rsl rise, which have caused significant coastline retreat and exposure to the northerly winds and waves, whereas parts of the coastal lowland, where the remains of the ancient city lie, are inundated, forming extended wetlands. The future impacts of rsl rise on the seafront of ancient Delos are illustrated on very-high-resolution digital surface models, evaluating both the flooding risk under different climatic projections, as provided by the IPCC AR6 report, and the ongoing land subsidence, as recorded by GNSS data. An rsl rise ranging from 87 cm (SSP1-2.6 scenario) to 148 cm (SSP5-8.5 scenario) is anticipated by 2150, requiring both resilience strategies and adaptation solutions as well as mitigation policies to cope with the effects of climate change