[VIDEOS] What secrets lie behind Chamrousse’s exceptional geological feature ?

In a new series of educational french videos proposed by Emilie Janots and Carole Cordier, teacher-researchers at ISTerre, you’ll discover the incredible history of Chamrousse’s peaks and the exceptional nature of this geological heritage. This series will be broadcast weekly from February 16, 2024 on the OSUG Youtube channel and will comprise 5 episodes, each lasting 1m30.

Less than 50 km from Grenoble and the university, the Chamrousse ophiolite in the Belledonne crystalline massif is an exceptional geological object, as it represents a complete section of oceanic crust, called ophiolite, that has escaped and survived several oceanic closures and continental collisions over the last 500 million years.

However, plate tectonics has seriously affected it, which is why today we find this section of crust "upside down" at the top of our alpine mountains. As we climb in altitude from the stations, we progressively encounter rocks normally found deeper and deeper within the oceanic crust. Until, near the Chamrousse cross on the Col de la Botte, we reach an outcrop of rocks known as peridotites, mantle rocks normally found a few kilometers below the ocean floor.

The aim of this series of videos is to inform the general public and the scientific community about this exceptional geological object in an educational way, while at the same time promoting the research carried out at ISTerre in the Alps.

The project was funded by the UGA Idex’s Rayonnement Social et Culturel call for projects, and was directed by Dorothée Adam of the Inuaprod production company.

Episode #1 : The peaks of Grenoble

In this first introductory episode, entitled "The peaks of Grenoble", geologists from the
ISTerre laboratory invite us to discover the geological history of the mountain ranges that we, the people of Grenoble, come into contact with on a daily basis.

In french

Episode #2 : Ascent to the earth’s mantle

Accompanied by a team of ISTerre geologists, take a deep dive and discover the rocks that make up the ocean floor, all the way to the earth’s mantle.

In french

Episode #3 : Chamrousse, France’s oldest ocean

ISTerre geologists present the radiochronology method for dating magmatic rocks, and more specifically those on the Chamrousse seafloor.

In french