Discover France and Explore the Fossils and Geodiversity of Digne les Bains in Haute Provence
- Wayne Munday
- 17 minutes ago
- 6 min read
Sip back and discover France and explore the fossils and geodiversity of Digne les Bains located in the foothills of the French Alps and serves as the gateway to the Haute-Provence UNESCO Global Geopark a remarkable landscape preserving over 300 million years of Earth’s history. Spanning more than 2,000 square kilometres the geological record dating back to Carboniferous coal basins and Triassic evaporitic sabkhas to Jurassic reefs, Cretaceous seas and Eocene coastal lagoons that were later transformed by the Provençal and Alpine orogeny's into dramatic mountains, gorges and folded limestone ridges. Its exceptional fossil sites including the Dalle aux Ammonites with over 1,550 Early Jurassic ammonites and in-situ ichthyosaur skeletons at La Robine-sur-Galabre and La Mélaie provide unique insights into marine life spanning the Jurassic into the Lower Cretaceous period. Further south, the Vallée des Siréniens preserves Eocene sirenian fossils the ancestors of modern dugongs and manatees. Beyond the fossils the geopark’s striking landscape includes the Crête de Géruen ridge to the Sisteron Gorge that illustrate the outcome of tectonic uplift, glacial sculpting and continuous erosion by the elements.
Located in the foothills of the French Alps is the spa town of Digne-les-Bains the prefecture of the Alpes-de-Haute-Provence department in the Provence-Alpes-Côte d'Azur region of south east France. Known as the gateway to the Haute-Provence UNESCO Global Geopark it is about 120 Km north east of Aix-en-Provence. This charming town lies in a valley carved by the Bléone River surrounded by fossiliferous cliffs of an ancient seabed, folded limestone ridges and lavender-scented landscapes that tell the story of 300 million years of Earth’s history. Beyond its historic centre, visitors can explore the Dalle aux Ammonites, a spectacular limestone slab preserving more than 1,500 ammonite fossils from the Early Jurassic seas. This is a must-visit destination offering an immersive experience in France’s fossil heartland.
This is a story of an ancient marine basin transformed into a mountain range through powerful tectonic forces. Here, every valley, ridge and gorge tells a story of shifting continents, evolving oceans teeming with life and the relentless geological processes that continue to shape our planet. The Musée Promenade in Digne-les-Bains serves as an interpretive hub for the Haute-Provence UNESCO Global Geopark.
Designated in 2000 as the world’s first Geopark and officially recognised as a UNESCO Global Geopark in 2015, Haute-Provence serves as the model upon which all subsequent geoparks have been built. At its heart lies the Réserve Naturelle Géologique de Haute-Provence, established in 1984 as France’s first national geological reserve and protecting nearly twenty key geosites of exceptional scientific value. Operated under the UNESCO International Geoscience and Geoparks Programme (IGGP), the geopark has become a global benchmark for the integration of science, education, and sustainable tourism.
At its centre lies Digne les Bains a tranquil spa town known since Roman times for its mineral rich thermal waters. From here the geopark extends towards Sisteron, Castellane and on to the Verdon Gorge forming a natural bridge between the Mediterranean lowlands and the southern Alps. This landscape owes its diversity to its position along the margin of the ancient Tethyan Ocean a tropical seaway later transformed by the Alpine and Provençal orogeny's of mountain building episodes that folded and uplifted once horizontal sea bed into the striking reliefs seen today.
The rocks of Haute-Provence span from Stephanian Stage a European regional stage of the Late Carboniferous back 300 million years ago to present day. During the Carboniferous and Permian the region was part of a continental basin filled with coal and river sediments. During the Triassic Period between 250 - 200 million years ago arid rift basins formed as the shallow sea that became restricted along the northern margin of the Tethys Ocean. The hot arid climate caused high evaporation rates in these hypersaline lagoons leading to the precipitation of thick layers of gypsum and dolomite in sabkha-like settings where periodic flooding by seawater alternated with periods of desiccation.
As time progressed into the Jurassic Period the Tethys Ocean inundated and transgressed the area depositing alternating limestones and marls that are teeming with marine fossils. By the Cretaceous Period to Eocene deeper marine conditions prevailed before African and Eurasian tectonic plates and Iberia-Sardinia-Corsica block collided compressing these sediments and thrust them upwards during the Alpine and Provençal orogeny which created extensive crustal thickening and formation of nappe structures and complex fold-and-thrust belts. Later, during the Quaternary Ice Age both glacial and meltwater erosion carved the region’s distinctive gorges and valleys notably the 700 metre high limestone Verdon Gorge.
Haute-Provence is internationally celebrated for its exceptional fossil record of marine life over more than 150 million years. Among its most famous sites is the Dalle aux Ammonites near Digne les Bains a steeply inclined limestone slab encrusted with over 1,550 ammonite fossils. Most belong to Coroniceras multicostatum, a species that lived in the Sinemurian Stage between 199.5 - 192.9 million years ago during the Early Jurassic.
Originally deposited on a tropical seabed, the slab was later tilted about 60° by Alpine tectonic uplift transforming it into a natural mural of Jurassic life. In 2022, the International Union of Geological Sciences (IUGS) recognised the Ammonite Slab among its “First 100 Geological Heritage Sites”, acknowledging both its scientific value and its role in public education and today attracts more than 20,000 visitors per year.
Another must-see destination lies to the north in La Robine-sur-Galabre where the Ichthyosaur Trail (Sentier de l’Ichthyosaure) leads visitors to an open-air museum protecting a 4.3-metre-long ichthyosaur fossil identified as a Stenopterygius. This marine reptile was discovered in the 1970s and dates to the Toarcian Stage of the Early Jurassic and was the first in Europe to be preserved in situ beneath a protective structure. The skeleton’s articulated vertebrae and preserved ribs illustrate the anatomy of these dolphin-like predators that once hunted ammonites and fish in the Tethys Ocean. Nearby, at La Mélaie, a second ichthyosaur fossil provides remarkable evidence of these marine reptiles’ persistence well into the Mesozoic Era, dating to about 107 million years ago within the Albian Stage the final stage of the Lower Cretaceous Period.
Further south, near Castellane, the Vallée des Siréniens (Sirenian Valley) preserves evidence of ancient warm coastal lagoons from the Eocene Epoch, once inhabited by early Protosirenidae sirenians the ancestors of modern sea cows of dugongs and manatees. These marine herbivorous mammals grazed on seagrass in the shallow tropical waters and their remains are exquisitely preserved in fine limestone.
Beyond remarkable fossil record of the Haute-Provence Geopark is its dramatic landscape. The Crête de Géruen is a limestone ridge rising to nearly 1,880 metres on the Monges Massif and overlooking the Duyes Valley and vividly shows how layers of ancient marine sediment were later transformed by intense tectonic uplift.
Further south the Clue de Sisteron (Sisteron Gorge) a spectacular limestone water gap has been carved by the Durance River between two towering ridges of the Rocher de la Baume and the Rocher de la Citadelle. Once part of the same Jurassic reef complex these formations were split by river incision along structural faults. The term clue isa Provençal word for a narrow gorge.
One of most extraordinary geological landmarks in the region is the towering sandstone and conglomerate pillars of the Penitents of Les Mées. These pillars were shaped over millions of years during the Oligocene Epoch. They rise dramatically and their narrow, elongated form is carved by differential erosion from wind, rain and frost. Named for their resemblance to early Christian hooded figures in a solemn procession the Penitents offer a surreal and otherworldly silhouette across the landscape.
Digne-les-Bains and the Haute-Provence UNESCO Global Geopark invites visitors to journey through 300 million years of Earth’s history amid the breathtaking scenery of the French Alps. From the Dalle aux Ammonites and ichthyosaurs of La Robine-sur-Galabre to the towering Penitents of Les Mées and the dramatic Sisteron Gorge every geosite tells a story of ancient oceans and mountain-building. Blending geology, biodiversity and Provençal culture this geopark offers a sustainable travel experience where science, nature, and heritage converge making Digne-les-Bains the perfect must-visit destination for those seeking adventure with deep time.
