Mourtzas, Nikos

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.

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.

Geomorphological survey along the coasts of Crete revealed widespread evidence of uplifted and submerged tidal notches, different phases of beachrock formation, and many relics of ancient coastal constructions. About 1.6 ka BP, when the sea level was at −1.25 ± 0.05 m, the western tectonic block of the island uplifted by 9.15 ± 0.20 m in its westernmost extremity and by 2.00 m approximately in its eastern boundary and tilted southeastward. Repeated preceding episodes of subsidence submerged the western part of the island by 1.60 m in a period of 2300 years. Along the western coast, the younger phase of the submerged beachrocks was identified and measured at nineteen locations, together with the submerged tidal notches and archaeological remains. Land subsidence by 1.25 ± 0.05 m, subsequent to the uplift of the western part, occurred after the late Venetian occupation period (∼AD 1600), coincident with the submersion of the eastern part of the island. In central and eastern Crete, the relative sea level change evidence from tidal notches and beachrocks revealed five distinct sea level stands at −6.55 ± 0.55 m, −3.95 ± 0.35 m, −2.70 ± 0.15 m, −1.25 ± 0.05 m and −0.55 ± 0.05 m. The lowest sea level stand can be identified with the oldest dated tidal notch of western Crete between 4200 ± 90 B P and 3930 ± 90 B P. Two subsequent sea levels can be linked with the Protopalatial (1900–1700 B C or 1600 B C) and Neopalatial period (1600–1450 B C) of the Minoan civilization, according to submerged prehistoric morphologies and inundated Minoan constructions. The change of sea level from −2.70 ± 0.15 m to −1.25 ± 0.05 m is placed between 1450 B C and the fourth century BC. The dating of −1.25 ± 0.05 m sea level stand was based on the measurement and interpretation of ancient coastal installations built along the coast of central and eastern Crete during Classical, Hellenistic, Roman, Byzantine and Venetian periods. Historical sources report a relative sea level rise by 0.70 m during the AD 1604 paroxysmal event. Over the last 400 years, the relative sea level rose by 0.55 m. The uplift of the coast of western Crete and the submersion in its central and eastern coast indicate that during the AD 365 paroxysmal event the island was split along a tectonic boundary identified with the neotectonic graben of Spili and its northern and southern prolongation.