The Tour de France and its Geography


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Ice Age Maximum Map-1

The last Glacial Maximum took place 18,000 years ago. Image by R. Geeta

Here I am, writing about the Tour de France, a sporting event, in an online magazine dedicated to decoding science. And here I am again, explaining geography as a science, but in this case, a bike race’s role in it. How does it all fit together? Well, it’s simple.

Everything relates to Gaia: The theory proposes that the organic (life) and inorganic (climate, tectonics) components of Planet Earth have evolved together as a single living, self-regulating system of critical biogeochemical cycles.

Each of these cycles is powered by sustainable solar energy and work to sustain conditions suitable for all life on earth. In this regard, biking is a sustainable activity that uses up precious few inorganic resources, and races like the Tour de France motivate people to do more cycling and get closer to nature.

But, I’m getting ahead of myself.

A few weeks ago I visited my hometown of Galt Ontario and rode its hills. Intuitively, I recalled the geomorphology, or the study of the landscape and the forces which created it, of the area of my youth. I remember, for example, the Galt moraine-overburden that runs diagonally across the area – it created a mass of glacial deposits 100, or more, feet thick and one and a half to three miles wide; and the kettle lakes swimming holes (e.g. Pinehurst) on the west side. And it made the bike rides up the steep hills of the Galt-to-Paris road worthwhile.

Tour de France Landscape

The nation of France, as a result of the rock and water cycles, has all of this and more, including, in particular, the sweeping plains in the west, the older uplifted Pyrenees in the south, and the newly uplifted Alps in the east. And the Tour de France, which started in 1903 as a way to increase paper sales for the magazine L’Auto, is twenty-one days long. This allows riders to get environmentally in touch with these flatlands, hills, and mountains of its namesake country in what is considered the toughest race on earth.

My wife and I religiously watched the race on television: We marveled at the helicopter shots of the Corsican seashores, the snow-covered mountain peaks, the switchbacks and hairpin turns, and the unique regional variations of the village architecture. As the Peloton snaked along city streets and rural roads before finally racing along the Champs-Élysées in Paris, the riders also experienced the majestic geography that included France’s heartland, the Riviera, the high Pyrenees, the French Alps and the outlying island of Corsica, the Grand Départ.

The Landscape Regions of France. Image by James Gibson

The Landscape Regions of France. Image by James Gibson

Corsica’s Geography

Stages 1-3 of the Tour took place on the island of Corsica, created when geological upheavals produced the granite backbone of the island. This uplift was followed millions of years later by a mass of sedimentary rock thrust up. The latter pressures caused a metamorphosis into a folded bed of hard, resistant schists. Like the Pyrenees, some final changes to the landscape were caused by the effects of glacial erosion on the highest peaks, but most change was from the island’s abundant precipitation, creating rows of parallel, steep sided, V shaped valleys indicative of fluvial erosion.

Folded Montains: Pyrenees

Stages 8-10 were raced in the Pyrenees which represent the geologic renewal of an old chain of folded mountains originally created by seafloor spreading during the Paleozoic era. Submerged and covered by secondary sediments, they were again lifted into two parallel chains running to the north and south of the original uplift. This was followed by glaciations. But unlike the newer Alps, there are no great lakes, and the glaciated U-shaped valleys, rather than acting as passes, often end in carved-out features called cirques.

Tethys Ocean Crust: The French Alps

The French Alps were the setting for stages 18-20. Originally simply a continental crust below the Tethys Ocean and collecting sediments, with seafloor spreading a collision occurred between the African and European plates. This tectonic plate collision compressed, lifted and folded the shelf. Since then glaciers have carved the surface.

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