Mont Gerbier de Jonc

Sainte-Eulalie / Saint-Martial

A pyramid of grey stone rising to 1,551 metres in the heart of the Monts d'Ardèche, Mont Gerbier de Jonc is a volcanic "suc": around eight million years ago, a phonolitic lava too viscous to flow out set into a dome above its feeder fissure, before the periglacial erosion of the Quaternary laid bare the present needle, girdled with phonolite scree. Its very name is a delicious puzzle: it is said to derive from the ancient roots "gar" (rock) and "jugum" (mountain), so that "Gerbier de Jonc" would speak neither of sheaves (gerbes) nor of rushes (joncs), but would say mountain twice over. It is at its foot that the Loire, the longest river in France, is born: three springs dispute the honour, the water seeping into the prisms of the phonolite and making its way through the fractured basalts before re-emerging at the base of the mount, where it meets impermeable ground. Listed as a site as early as 1933 and a geosite of the Monts d'Ardèche UNESCO Global Geopark, the Gerbier is climbed in some thirty minutes by a steep path waymarked in blue, a few sections of which are fitted with ropes; from the summit, the eye takes in the whole plateau of the sucs.

Getting there : Free car park at the foot of the mountain; waymarked ascent of about 30 minutes, steep, a few sections fitted with ropes, descent by another path; good footwear essential.

Opening times and access details are given as a guide only: check before you set out.

Ambient sound