The geology of the Lodève Basin
After: Saint-Martin et al 1989
The area between the Montagne Noire, the Causses and the
Languedoc plain is called the Lodève Basin. It is a continuation of
the Graissessac Basin where coal beds from the Stephanian are exploited in
open pits. About the stratigraphy of the Lodève Basin is no unanimity.
But the 'Autunien gris', to which the rock of the quarry Les Tuilières
belongs, is always placed in the Upper Autunian. The age is thus about 280
million years.
At that time the landscape was mountainous and cut with river
valleys. The debris of the plants which were carried along by the rivers,
were deposited in quiet water in lakes.
Above the 'Autunien gris' is the formation 'Autunien alternant rouge
et gris'. The red colour, indicating a hot, dry climate, is dominating in
these layers.
Above the 'Autunien gris alternant' is the 'Autunien rouge' which is, as
the name indicates, completely red. There are very few fossils in this
formation.