Located in the older Sancy massif, Lake Pavin was formed relatively recently (6,900 years ago) after the period of volcanic activity that gave rise to the Puys chain (between 95,000 and 8,600 years ago) though it isn’t linked to them. The phreatomagmatic eruption which created Lake Pavin, of an estimated volume of 75 million cubic metres, had repercussions as far away as Switzerland, particularly in the sediments of Lake Geneva.