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Motivation: Past sea level fluctuations have shaped island area and archipelago configuration. The availability of global high‐resolution data on bathymetry and past sea levels allows reconstruction of island palaeo‐geography. Studies on the role of palaeo‐area often consider only the Last Glacial Maximum, which neglects the dynamics of island fusion and fission resulting from cyclic sea level fluctuations throughout the Quaternary. Currently, no global database is available to test the role of changing island geographies driven by Quaternary sea level change on evolutionary, ecological and archaeological patterns. However, data on island palaeo‐environments is crucial for understanding insular biodiversity distributions and human settlement patterns. Here, we present the Palaeo‐Islands and Archipelago Configuration (PIAC) database, containing sea level‐driven palaeo‐geography changes over the late Quaternary of 178 islands in 27 archipelagos, and discuss its relevance, limitations and uncertainties. The R functions developed to create the PIAC database are provided to allow calculations for other islands, time steps, sea‐level curves and higher spatio‐temporal resolutions.Main types of variables contained: Polygon shapefiles with archipelago configuration and tables with palaeo‐area per island.Spatial location and grain: The database has a global representation, with 27 archipelagos being covered: Aldabra, Azores, Balearic Islands, California Channel Islands, Canary Islands, Cape Verde, Comoros, Cook Islands, Crozet Islands, Dutch Caribbean, Galápagos, Gulf of Guinea, Hawaii, Inner Seychelles, Juan Fernández, Kuril Islands, Madeira, Marianas, Marquesas, Mascarenes, Phoenix Islands, Pitcairn Islands, Prince Edward Islands, Revillagigedo, Samoan Islands, Society Islands and Tristan da Cunha. All data are at 1 km2 spatial resolution. Time period and grain: The focus of this paper is on the last 35 kyr; data for the last 140 kyr are also provided. The grain is 1 kyr temporal resolution.Level of measurement: Data are per island, grouped per archipelago.Software format: The data were produced in the R programming language.

Les observations paléoenvironnementales effectuées sur les différents sites présentés dans ce dossier renouvellent fortement notre perception de l’histoire du paysage dans la basse vallée de l’Argens, dont on perçoit désormais beaucoup plus finement la paléogéographie et la diversité des environnements littoraux. Ces premières restitutions paléogéographiques doivent être affinées en multipliant les points d’enregistrements morphosédimentaires et en confrontant les observations paléoenvironnementales aux données relatives à la morphologie du paysage et à l’occupation du sol, de manière à pouvoir proposer une restitution synthétique de l’évolution du paysage au cours de l’Holocène sur l’ensemble de la basse vallée. Palaeo-environmental data collected on the different sites presented above strongly improve our perception of landscape’s history of the lower Argens valley. They allow to reconstruct the palaeo-geography of the valley and show the diversity of coastal environments. More morphosedimentary data must be collected in order to precise these preliminary palaeo-geographical reconstructions. The confrontation of palaeo-environmental data with ancient landscape and settlement patterns will also allow us to propose a synthetic model of landscape’s evolution in the whole lower valley during the Holocene.

International audience

International audience; The famous Greek geographer Strabo wrote in the fi rst century A.D., that Piraeus was formerly an island and lay 'over against' the mainland, from which it got its name. To validate Strabo's hypothesis, cartographic and historical data were compiled with multiproxy paleoenvironmental analyses and radiocarbon dating from a series of boreholes drilled in the Cephissus coastal plain, southwest of Athens, Greece. The results of this interdisciplinary geoarchaeological research demonstrate the reliability of Strabo's text by revealing that Piraeus was indeed an island. In early Holocene time, the rocky hill of Piraeus was linked to the mainland of Attica. During the late to fi nal Neolithic Period (4850-3450 B.C.), Piraeus became an island in a shallow marine bay, due to sea-level rise in the Holocene. Between 2850 and 1550 B.C., in the Early and Middle Bronze Age, Piraeus was separated from the mainland by a wide lagoon. In the fi fth century B.C., Themistocles, Cimon, and then Pericles connected Athens to Piraeus by building two "long walls" partly built on a residual coastal marsh called the Halipedon. This study reveals an impressive example of past landscape evolution

Palaeo-environmental data collected on the different sites presented above strongly improve our perception of landscape's history of the lower Argens valley. They allow to reconstruct the palaeo-geography of the valley and show the diversity of coastal environments. More morphosedimentary data must be collected in order to precise these preliminary palaeo-geographical reconstructions. The confrontation of palaeo-environmental data with ancient landscape and settlement patterns will also allow us to propose a synthetic model of landscape's evolution in the whole lower valley during the Holocene; Les observations paléoenvironnementales effectuées sur les différents sites présentés dans ce dossier renouvellent fortement notre perception de l'histoire du paysage dans la basse vallée de l'Argens, dont on perçoit désormais beaucoup plus finement la paléogéographie et la diversité des environnements littoraux. Ces premières restitutions paléogéographiques doivent être affinées en multipliant les points d'enregistrements morphosédimentaires et en confrontant les observations paléoenvironnementales aux données relatives à la morphologie du paysage et à l'occupation du sol, de manière à pouvoir proposer une restitution synthétique de l'évolution du paysage au cours de l'Holocène sur l'ensemble de la basse vallée