350 million years ago

Two continental blocks collided, giving rise to a high mountain chain.

250 million years ago

Over time, the weather gradually eroded and flattened the mountain chain

35 million years ago

During the formation of the Alps, the Earth’s crust stretched and fractured, creating the Limagne graben. The base of this trough was so low that it started to fill with water.

From 35 to 12 million years ago

Sediments progressively filled the graben. A first phase of volcanism took place in the Limagne Plain: more than 280 volcanoes formed, including Gergovie, Crouel and the ‘Côtes de Clermont’ plateau.

3.5 million years ago

A lava flow was channelled by an existing valley. At depth, huge-scale movements in the mantle created enough heat to cause uplift at the surface, leading to intense erosion. While the volcanic lava flow resisted erosion, the softer surrounding sediments were removed. Thus the relief became inverted, with the lava flow now forming the Montagne de la Serre.

Today

700 m of sediments have been removed through uplift and erosion: the plane of the Limagne Fault has been exposed making it visible now. From 95000 up to 8000 years ago, the Chaine des Puys were active vocanoes