In May 2025, around 20 researchers from Section 4.7 travelled to the city of Rennes and the Brittany region of France for a week. The aim was to strengthen collaboration with colleagues from the University of Rennes and to explore the geological outcrops of Brittany in France. 

Each researcher gave a brief five-minute presentation on their current work, after which there was a fruitful exchange with the Rennes-based researchers, who also presented their ongoing projects.

As part of the visit, the group conducted fieldwork, exploring significant geological outcrops in the Armorican Massif and focusing on its intricate Cadomian and Variscan tectonic history. They stopped at the Maison de la Baie de Saint-Brieuc in Hillion, as well as at volcanic and sedimentary sequences near Erquy and Cap Fréhel. They examined coastal cliffs and ancient volcanic-sedimentary sequences, such as the Lanvollon Formation, as well as structural features associated with Cadomian and Hercynian deformation.

Along the Emerald Coast, the team conducted a LIDAR survey of a coastal cliff and a tidal channel in collaboration with Dimitri Lague and Philippe Steer (University of Rennes/CNRS). The team also visited the Bay of Mont Saint-Michel, a striking example of a macro-tidal environment. There, they studied sedimentary dynamics shaped by the extreme tidal range and observed processes of erosion, deposition, and channel evolution. The visit concluded with a guided walk across the bay to the islet of Tombelaine, led by a local specialist.

This trip provided valuable scientific insights into Brittany’s distinctive geology and strengthened the relationship between the two institutions, paving the way for future collaborative research.