Grand Canyon, a journey to the center of the earth

Alongside a couple of passionate geologists, a fascinating journey along the Colorado River to discover the Grand Canyon, a natural monument still far from having revealed all its secrets. 

The Grand Canyon is one of the most famous landscapes on the planet. An astounding natural monument: 450 kilometres long, 30 kilometres in its widest part, 1,300 metres of average depth. Place of history and mystery, this spectacular gorge marking the Colorado plateau in northern Arizona is a giant whose age and formation are still debated. But to access the wealth of this open-air geological laboratory, you have to launch on the Colorado River that cuts the Grand Canyon and cross a hundred rapids, some of the most dangerous in the world. Accompanied by "river runner" Glade Zarn, who knows the river like the back of his hand, and naturalist Geoff Carpenter, Karl Karlstrom and Laurie Crossey, a couple of American geologists, embark on an eight-day boat trip, in the footsteps of Major Powell, who in 1869 embarked on what he then called the "Great Unknown". As the rapids and meanders pass by, seen from below, a landscape of yellow, grey and ochre rocks, formed by twenty sedimentary layers patiently dug by the river: an unexpected playground for researchers.

Mineral millefeuille

Although Karl and Laurie have done it dozens of times, the descent from the Grand Canyon is always an eventful adventure that would be impossible to undertake without the expertise of Glade. The two geologists, who have devoted much of their research to it, Don’t shy away from this mineral millefeuille, which alone tells almost two billion years of the earth’s history – the age of the oldest rock visible at the bottom of the gorge. In this documentary with spectacular images, we follow them through a journey through time where each stone tells of part of the geological processes that have formed the landscape that is discovered: a succession of tectonic movements and sedimentations, Punctuated by climatic upheavals – glaciations, floods and desertification – and phases of explosion of animal life, like the one that occurred in the Cambrian 500 million years ago. All exposed by the erosion started by the Colorado and its tributaries "only" 6 million years ago, a trifle on the scale of the Earth... Today, it is the human being who imprints his mark on the life of the canyon. But although it is blocked by two dams, which have altered the river’s ecosystem and caused it to lose its former ardor, the Grand Canyon, carved by the elements, is still alive. Each speed embodies this dynamic, which these science adventurers share with us until the end of their journey.