The extinct Cantalian volcano is a
stratovolcano, composed of alternate pyroclastic and lava flow eruptions.
Typically, this type of volcano erupts many thousands of times over millions
of years, beginning with ash explosions and ending with the extrusion of
thick viscous lava flows.The volcanic rock varies
from basalt to rhyolite, but is generally andesite.
The centre of the Cantalian
volcano is Puy Griou, whose central zone was active for hundreds of millions of
years, giving it a conical form, later reshaped by erosion. Its flanks were also
deformed by lateral eruptions.
With an area of 2700km², the Cantalian
Mountain is equal to two Mount Etnas and four Mont Dores. It is spread in an
ellipse with a diameter of 80km by 60km, and a circumference of 220km. It
occupies half of the département du Cantal. Only a small part to the
south, around Mur-de-Barrez, lies in the administrative district of Aveyron.
Its highest summit, the Plomb du Cantal 1855m, is almost as high as the
highest of the Massif Central, Puy Sancy 1885m, in Mont Dore. According to
the hypothesis it is believed to have attained 2500 – 3500m altitude at the
top of Puy Griou. Today it does not rise above 1000m from the valley,
against 3300m of Etna.
Walking in
the Cantal for information on walking and walks in France
and the Cantal, accommodation, food and wine.
