The Rocher de la Baume, a true natural monument of Sisteron, fascinates with its vertical layers and unique appearance. But how did this giant of stone, which evokes the famous dessert mille-feuille, come to be? Let’s dive into the history of this rock, a result of a fascinating geological journey.
The formation of the Rocher de la Baume: a journey of 150 million years
Millions of years ago, the Sisteron region was beneath an inland sea, the Thethys, whose sedimentary deposits gave birth to the limestone layers that make up the rock today. These layers, once horizontal, were suddenly uplifted by successive tectonic movements.
The Thethys sea deposited limestone sediments, forming a massive rocky bar. Around -70 million years ago, the Pyrénéo-Provençal phase began, radically transforming the region. This displacement pushed Iberia, once further northwest, closer to Corsica and Sardinia. This geological play resulted in a great compression of the plates, transforming the horizontal layers into vertical folds that shape the Rocher de la Baume today.
Breathtaking tectonic phenomena
Over the ages, the movements of the plates have redrawn the landscape. During the formation of the Alps, around -35 million years ago, intense deformations changed the entire region. The Rocher de la Baume is aligned with other iconic landforms such as Mont Ventoux, Montagne de Lure, and Montagne Sainte-Victoire, all oriented along an east-west axis.
When the earth becomes mille-feuille
What makes the Rocher de la Baume unique is its appearance as a natural mille-feuille. These folded layers are due to the combined action of tectonic movements and erosion. Rain, wind, and frost have contributed to sculpting the rock, removing the softer layers and leaving only the most resistant limestone strata. Over the years, the landscape has been shaped into a natural monument that stands proudly facing the Durance.
Sisteron, a witness of a bygone era
The Rocher de la Baume, with its geological folds and unique rock formations, is much more than just a rock: it is a witness to the forces of nature that have shaped Provence. As you stroll at the foot of this imposing natural monument, let yourself be transported to another time, when the sea covered these lands and titanic forces were reshaping the landscape.
This mille-feuille of rock and limestone is proof that the forces of nature have always played a decisive role in the sculpting of our environment. So the next time you pass through Sisteron, look up and admire the millennia of history that the Rocher de la Baume holds.
