Geology of the Tour de France and the Tour de France Femmes: Earth science meets cycling

Published 04-07-2023

The Grand Départ was 1 July, but the preparations for this year’s Tour de France started more than 400 million years ago, when the rocks of the Central Massif and the Vosges Mountains were formed. Behind every climb, descent, or flat stage is a geological reason, and the team behind explains the geology that created the race parcours.

A cyclist climbed kilometers up to arrive in deep-oceanic rocks, high in the Alps. (Photo: Pete Lippert)

Descriptions of the natural decor of each stage of the Tour de France; the various landscapes and the treasures that are found below the surface, for both the men’s and the women’s races, are available at During this year's Tour de France Femmes, the team will pay special attention to female pioneers in the development of Earth science.

“Much more than in other sports, a cycling race is an event where you can enjoy the surroundings”, says Geologist Douwe van Hinsbergen, Professor at Utrecht University and die-hard cycling fan. “So I decided to share our knowledge and the underlying geological treasures with the public, in a fun and accessible way, together with my fellow earth scientists from the Netherlands and abroad.”

The future of the past, Stage 8 of Tour de France Femmes

The researchers include Kasia Sliwinska, Senior Researcher at the National Geological Survey of Denmark and Greenland (GEUS). Sliwinska’s contribution is about the final day of the race, Stage 8 of the Tour de France Femmes. This day brings us to the north of the Pyrenees. The stage is around the city of Pau, located in the Aquitaine Basin. The Aquitaine Basin gave name to the geological time interval known as the Aquitanian, between 23 million and 20 million years ago. Sliwinska explains how researchers can learn about the future by looking into the climate of the past in the traces left below the grounds surface.

During the Miocene, a warming occurred that is thought to be caused by increases in atmospheric CO2, likely due to intense volcanism. The relatively rapid rise in CO2 can be considered one of the best analogies for future climate. By studying the temperature development on land and in the ocean, changes in the size of the Antarctic ice sheet or sea level in this Miocene climatic optimum, researchers are better able to get a grasp of how the global climate will be affected by rising CO2 levels in the future.
Sliwinska also pays tribute to Danish pioneer, Inge Lehmann, who revolutionized our understanding of structure of Earth structure by suggesting the presence of a solid inner core.

Find Sliwinska’s blog and take a dive into past here at

Swiss cheese and clean laundry

This year, the Tour de France will once again race through the varied landscapes of France, and also northern Spain. To name just a few: the Swiss cheese of the Basque Country hills, a volcano that was once Europe’s largest in the Auvergne, rocks folded like a pile of clean laundry in the Alps, and a series of dinosaur tracks in the Jura. If you are curious how these phenomena were created, how you can recognise them, and how they affect our lives today, then take a look at and the linked social media channels.

Send pictures

“The audience can also share photos and ask questions on Twitter and Instagram via the hashtag #GeoTdF”, adds Van Hinsbergen. “And during the Tour, we’ll provide daily commentary via our Twitter account @geotdf.”

Fans can also follow Geo-Sports via other social media channels.

12 countries, 4 continents is an initiative by Utrecht University and the Naturalis Biodiversity Center, both in the Netherlands. Thirty researchers from 25 different institutes in 12 countries on 4 continents participated in the project.
The website is in English, Danish, French, German, Dutch, Spanish, Italian and several other languages.

Kasia Sliwinska
Senior Researcher
Geo-energy and Storage
Malene David Jensen-Juul
Communications Officer
Press and Communication