Conférence - Archéo‑littoral

The theme of the conference will be prehistoric submerged structures around the Île de Sein. The conference will be hosted by the SAMM (Société d'archéologie et de mémoire maritime) and presented by Yves Fouquet, scientific coordinator, and Jean Roullot, a Penmarc'hais diver. The meeting, which is open to all, is being steered by the scientific committee headed by Philippe Davy, director of research at the CNRS. A keynote speaker: Yves Fouquet Yves Fouquet, a geologist from the Île de Sein and former researcher at Ifremer, is internationally renowned for his scientific explorations of deep-sea volcanoes and associated hydrothermal springs. He will be presenting a major archaeological discovery made recently off the Ile de Sein: a series of submerged structures, including a 120-metre-long wall, dating back more than 7,000 years. The discovery was made by members and divers of the SAMM association (Société d'Archéologie et de Mémoire Maritime) based in Fouesnant... Jean Roullot, from Penmarc'hais, a diver with the SAMM and a participant in explorations and the discovery of submerged walls, will speak at the end of the scientific presentation. A major archaeological discovery off the Ile de Sein Identified using LIDAR maps of the seabed (laser beam mapping from an aircraft, Litto3D® programme), these structures were explored by diving between 2023 and 2025. The ensemble includes small dams interpreted as former fish traps and larger structures that may have had a protective role against swell and storms. The large structures, made up of an accumulation of reinforced monolithic blocks and large granite slabs, demonstrate a high level of technical know-how and social organisation more than 500 years before the start of Breton megalithism. These remains, attributed to the Late Mesolithic period, bear witness to a time when the sea level was around 7 m lower and the Ile de Sein extended over more than 8 kilometres. Understanding the past to shed light on the future of the coastline Through this remarkable discovery, the conference will highlight the way in which ancient societies interacted with their coastal environment and adapted to rising sea levels, offering an enlightening look at past transformations and current issues.