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Geological curiosity, the Pourcheyrolles waterfall was born from a volcano. It springs from a basaltic flow 32 m high overlooking the Fontaulière.
Visible from the belvedere Pourcheyrolles bordering the RD 536.
Formation of a valley by the effect of two phenomena: the juxtaposition of two lava flows formed in basaltic organs (the volcanoes of the Chambon and Gravenne-de-Montpezat volcanoes) and their incision by the watercourses of la Pourseille and La Fontaulière. From this site, a cascade of 32 meters flows into the Fontaulière.
The territory of Montpezat-sous-Bauzon has five volcanoes, including the Maar du Chambon whose lava flow (from the strombolian phase of the volcano) joins that of the Gravenne de Montpezat (Strombolian volcano). The casting of the Gravenne covers the crystalline base of the valleys of Fontaulière and Pourseille, before being re-incised by these same rivers. The eruption of the volcano Chambon then fills the valley of the Pourseille (abutting on the flow of the Gravenne) before the stream erodes again to form his bed. The rivers meet today at the foot of the Château de Pourcheyrolles, laying bare basalt organs: Fontaulière side appear the prisms of the Gravenne; side Pourseille those Chambon. The prisms from the Gravenne-de-Montpezat are interrupted by a formation of basalt in stack of plates. La Pourseille ends its race with a cascade dropping more than 32 meters into the Fontaulière from the top of the basaltic prisms. Le Chambon has emitted lahars (mudslides), a rare phenomenon on a European scale: it is possible to observe them in the hamlet of Fau. The basaltic organs of Pourcheyrolles present a formation in "stack of plates".