The biggest protected geology reserve in Europe has unique places to discover: geology sites, fossils and landscapes with folded and fractured layers.
Created in 1984 by decree, Natural National Geology Reserve of Haute-Provence is spread over a 230,000-hectare territory and 59 municipalities in the Alpes de Haute Provence and the Var.
Managed since 2014 by the Department of the Alpes de Haute Provence, it has three types of mission: the conservation of the geological heritage, the sensitization of the general public and ensuring the increased knowledge of this geological heritage.
A few exceptional geological sites
Among the geotopes highlighted, we must mention the ammonite slab of Les Isnards in Digne-les-Bains, the icthyosaurus fossil-bearing sites of La Robine-sur-Galabre and the Sirenians site in the Tabori ravine in Taulanne.
The ammonites slab in Digne-les-Bains
Its fame has gone well beyond the borders of the Digne region. Even the Japanese are interested in it: a museum in Kamaishi houses a copy of the slab.
The slab numbers over 1,550 ammonites on a surface of 320 m2. The ammonites are big and the biggest have a diameter of 70 cm. Their scientific name is Coroniceras multicostatum. This species has made it possible to date the slab at approximately 200 million years ago (Lower Jurassic).
The shells of these ammonites accumulated on what was once a sea bed. They were then covered by thick sediment. Over millions of years, the old muddy deposits and the remains of the shells have become rocks and fossils.
During the tertiary era, the region was in upheaval with the surrection of the chain of the Alps. This is why the slab is now at an altitude of over 600 metres with a 60° gradient.
The ichtyosaurus of La Robine-sur-Galabre
The ichthyosaurus is one of the most impressive fossils. Its name comes from the Greek words ikhthus: fish, and sauros: lizard, because it looks like a fish but is actually a reptile.
The shape of its highly hydrodynamic body resembles that of a shark or a dolphin. Its four limbs turned into swimming appendages and its dorsal fin and its bilobate tail made it a very fast mover. It had lungs which meant that it had to take surface regularly to take in air.
Ichthyosauridae disappeared towards the end of the secondary era, about 90 million years ago, long before the extinction of all the big reptiles 65 million years ago. They were probably replaced by the Mosasauridae, who wer new large sea predators.
The ichthyosaurus of La Robine is around 185 million years old. When it died, it was covered in a very wet mud and a bacterial veil which protected its skeleton. The mud became charged with rock and the fossilized skeleton imprisoned in the rocky gangue was preserved.
Find out more
The ichtyosaurus of La Robine-sur-Galabre walk: www.rando-alpes-haute-provence.fr/ichtyosaure/
The Valley of the Sirenians in the Tabori ravine, near Castellane
The Sirenians walk takes you to a site which is the only one of its kind in the world. You will see 40 million year-old bones preserved on the spot.
A short 4-km out and back family walk starts from the Col des Lèques and 8 km from Castellane on the way to Digne-les-Bains. It takes you to the geological site where you will see the fossilized remains of Sirenians, the ancestors of dugongs and manatees.
If the Sirenians of the Tabori ravine, who were sea-dwelling animals, are now to be found at an altitude of almost 1,000 metres, it is not due to a sudden lowering of the water level, but due to the sediment which accumulated vertically on the sea bed for millions of years actually being at a high altitude when the Alps rose.
Find out more
The Sirenians walk: www.rando-alpes-haute-provence.fr/site-des-sireniens-mammiferes-marins-fossiles/
Museum in Castellane: www.maison-nature-patrimoines.com
Find out more