La Limagne: The cliff of Jussat and the necks of Buron and Saint-Babel.

Before definitively stopping writing my blog, for various personal and technical reasons, I am sharing for a few days the photos of my Belgian volcanophile friends, all recent, from their visit to the Cantalien Massif (France), via La Limagne .

Some sites of La Limagne, to whet your appetite!

The cliffs of Jussat and the stromatolites:

Limagne is the region of France richest in fossil stromatolites, of ages corresponding to the Upper Oligocene / Lower Miocene.

The Jussat deposit presents a cliff made up alternately of sand with quartz levels, and others of marl and limestone, with cauliflower balls of stromatolites, created by colonies of cyanobacteria, overhanging a less resistant layer. to erosion.

The necks of Buron and Saint-Babel:

They were formed around 20 million years ago, when a rise of magma through sedimentary rocks dating from the Tertiary period formed a lava lake. This lake then cooled and solidified, then was revealed by the erosion of the sedimentary rocks that surround it, very loose and friable.

The neck of Saint-Babel overlooks an area rich in peperites, which result from the encounter between magma and water (underground or surface), during a phreatomagmatic eruption.

Sources:

- Guide to the volcanoes of Europe and the Canary Islands / La Limagne - M. Krafft and Larouzière, ed. Delachaux & Niestle.

- Planet Terre: Auvergne, a museum of stromatolites / The cliffs of Jussat (Chanonat, Puy de Dôme).