Sentier karstique de Sorèze

Les secrets du Causse de Sorèze


Useful Information

Location: Plateau du Causse de Sorèze, 81540 Sorèze.
Parking: 3 Chem. du Tour du Parc, 81540 Sorèze.
(43.4456522, 2.0847132)
Open: no restrictions.
[2023]
Fee: free.
[2023]
Classification: TopicSentier Karstique KarstKarst SpeleologyKarst cave
Light: bring torch.
Dimension: L=10 km, VR=600 m, D=3 h.
Guided tours: self guided
Photography: allowed
Accessibility: no
Bibliography:
Address: Sentier karstique de Sorèze.Téléphone : 05 63 74 16 28 E-mail:
Frédéric Verp, Société de Recherches Spéléo-Archéologiques du Sorézois et du Revélois E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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History

1973 Haut-Languedoc Regional Natural Park created.
1966 archaeological discoveries in the Grotte du Calel by cavers of the Société de Recherches Speleo Archéologiques du Sorèzois and Revèlois.
1973 archaeological discoveries in the Grotte du Calel by cavers of the Société de Recherches Speleo Archéologiques du Sorèzois and Revèlois.
1989 to 1995 excavations in the Grotte du Calel.
26-SEP-2015 karst trail inaugurated.

Description

Sentier karstique de Sorèze (Sorèze karst trail) is named after the Causse de Sorèze, a karst plateau southeast of the town Sorèze. The trail is also called Les secrets du Causse de Sorèze (The secrets of the Causse de Sorèze). The starting point is on top of the plateau, which is a little impractical. It is actually an “annex” to the marked hiking trail from Sorèze, a funny way to put it. The official starting point is the huge parking lot at the abbey of Sorèze, which is free. From here it's an 800 m walk through the park to the cemetery, from where the trail to the plateau starts. Of course, you can also park your car here if you are lazy, with restrictions. The total length of the trail from the parking lot is 10 km, it starts with an ascend of 300 m, the trail on the plateau is mostly level, at the end you have to walk back down again.

Roc de la Fendeille is of geological interest. Although the Grande Mine is not a natural feature, it is an abandoned open cast iron mine. There are several surface karst features like the Doline de l'Erable (Maple Doline). Other sites are the karren fields, limestone pavements and the numerous pertes (swallow holes). The area is dry, almost semi arid during summer, so there is not much swallowing going on. But during winter rains many dry valleys are reactivated and the brooks flow to the next swallow hole where they go underground to replenish the karst aquifer.

The caves along the trail are the Grotte du Calel (Calel Cave), the Grotte des Gours (Cave of the Rimstone Pools), the Grotte Sépulcrale (Sepulchral Cave), and the L'aven de Polyphème (Pit of Polyphemus). The trails are rather dangerous and not entered during the trail. They are only accessible for speleologists. The Causse de Sorèze is an important karst area with a total of 7,000 m of cave passages in 38 caves. The caves are typically between 130 and 150 m deep, in other words there are many shafts or vertical section, requiring good climbing skills and equipment. There is long history of speleological exploration.

The plateau consists of 540 million years old Cambrian limestone with iron concentrations in the form of iron hydroxides – mainly goethite. This is quite unique, as other surrounding karst areas do not have any iron deposits. The iron was mined during the Middle Ages. Numerous remains can be found, like charcoal pits, open cast mines, and furnaces. Many caves have remains of Medieval mining in the entrance section.

But the age of the limestones is also quite astonishing, as most limestones are much younger, deposited during the Mesozoic. The Cambrian is the first period where animals populate the sea, but most species which later produced limestone in form of skeletons or shells did not yet exist. Also, it was either metamorphized by later tectonic events or weathered and eroded. For this reason there is not much limestone of this age. The limestone was underground without being metamorphized until it was lifted during the orogeny of the Pyrenees 30 to 50 million years ago. The karst developed since then.

Again much younger is the Plestocene content of the caves. The bones of bears, reindeer, chamois, cave lion, moose, aurochs, and horses dating from the last ice age were discovered in the caves.