The small valley of Bonnan is towered over by the sheer faces of limestone cliffs. Over this 11km route, you will discover a landscape which alternates between green meadows, arid, barren hillsides and the grassy expanses and twisted oaks of the Caussenard plateau.
A tuff waterfall:
In karstic regions, infiltration water causes the formation of dolines (closed depressions in the relief) and other avens by dissolving the limestone. Most of the time, they reappear in the form of Vaucluse springs. A similar phenomenon exists in the Bonnan valley in the form of a petrified waterfall.
The event occurs during periods of high water. The water pours down in a tuff cascade (non-homogeneous porous rock, often powdery, in this case of sedimentary origin) over a height of about forty metres to cover the sandstone (stable mixture of rock and clay). A natural well collects them. Once underground, they resurface as a Vaucluse fountain at Gourp de Fénérols.
In the country
Tarn Tourisme - 10/10/2024
www.tourisme-tarn.com
Report a problem
All year round.
Phone : 05 63 47 73 06
Email : tarn@ffrandonnee.fr
Website :
www.randonnee-tarn.com
www.tourisme-tarn.com/a-voir-a-faire/balades-et-randonnees/trouver-une-randonnee
Topo guides references :
PR08 - Topoguide "Le Tarn à Pied" on sale at the Espace des Destinations Tarnaises et de la Randonnée, 14 rue Timbal, 81000 Albi.