New investigation and results at the Olbia-de-Provence (France, Var, Hyères): harbour structures

International audience; Founded during the 4th century BCE, Olbia-de-Provence, a colony of Massalia (Marseille), features submerged structures that have been known since the 1970’s. The 2019-2022 campaigns held on the site produced a new, full documentation of these hundred meters long structures in particular thanks to photogrammetry. The interpretation of this documentation, the architectural and archaeological study of the structures preserved will lead to a series of new interpretations regarding the dating and the function of these remains. The field campaigns brought some of the data missing for the global understanding of the harbour. The dating of those remains can be approached thanks to the discovery of a small amount of amphora pieces caught in the masonry. Trenches in the center of the main construction show some of the construction techniques employed. Test-trench on both sides complete the observations made in the past on the harbour basin, and its localization. Thus, this proposal aims to discuss the documentation and the data collected, present new hypothesis on the construction the main structures and show evidences of its dating.