The Ammonite Wall of Digne-Les-Bains: A Closer Look at This Geological Marvel

The Ammonite Wall of Digne-Les-Bains

The Ammonite Wall, or Dalle à Ammonites, located in Digne-les-Bains in the Alpes-de-Haute-Provence region of France, is a fascinating natural site that draws attention from geologists and fossil enthusiasts alike.

Displaying an impressive collection of fossilized ammonites, this notable attraction boasts a vast rock stratum that serves as a gateway to the Earth’s prehistoric past. The site is nestled approximately 1.5 km south from Digne-les-Bains, in the vicinity of Barles road, and offers a unique opportunity for visitors to explore the ancient remains of these extinct marine creatures.

The Ammonite Wall, a product of the Lower Jurassic period, lies within the Subalpine Basin marly-limestone sequence and is part of the Nappe de Digne. This remarkable slab records the early history of the Southeast Basin in the enigmatic Alpine Tethys Ocean during a time of rampant rifting.

Covering an area of 320 square meters, it houses more than 1,500 ammonites, with some reaching diameters of up to 550 cm. The scientific name for these ammonites is Coroniceras multicostatum, providing valuable insight into their history, dating back nearly 200 million years.

The Ammonite Slab

Dalle à Ammonites — The Ammonite Slab in Digne-les-Bains, France (credit: Banco Imagenes Geologicas)

The Ammonite Slab of Digne-les-Bains is an impressive natural formation showcasing a rock layer containing more than 1,550 fossilized ammonites and nautili. Spanning over 320 m², it hosts large ammonites with diameters reaching up to 550 cm. This unique assemblage provides an invaluable resource for scientific research and draws numerous visitors every year.

The fossils found at this site, specifically the Coroniceras multicostatum species of ammonites, date the slab to around 200 million years ago, during the Lower Jurassic period. The Early Jurassic is known for its diverse marine ecosystems, with benthic fauna being abundant. Thus, the Ammonite Slab of Digne-les-Bains stands as an ideal biostratigraphic marker for establishing correlations with faunas from the Mediterranean Tethys region.

The ammonite wall is composed primarily of limestone originating from the Barles area, which was once covered by a shallow sea. The preservation of the ammonites and their surrounding sediments allows researchers to study the sedimentology of the Early Jurassic period, gaining crucial insights into the depositional and diagenetic history of the region. This contributes significantly to the understanding of submarine paleoenvironments and the evolution of marine life during this geological era.

Location and Accessibility

Digne-Les-Bains

The Ammonite Wall of Digne-Les-Bains is situated in the Haute-Provence Geopark in France¹. This impressive geological site is located approximately 1.5 km south of Digne-les-Bains along the Barles road². The area is known for its rich paleontological finds, with over 1,550 ammonites predominantly of the species Coroniceras multicostatum³.

Nice

Visitors traveling to the Ammonite Wall from Nice, located in the French Alps, can access the site via a scenic drive through picturesque landscapes. Nice is about 172 kilometers away from Digne-Les-Bains⁴. The trip takes approximately 3 hours by car, passing through the city of Grasse and the beautiful Prealpes d’Azur Regional Natural Park before reaching Digne-Les-Bains.