Granitic outcrops are abundant in the Massif Central. The Chassezac, in Lozère, cuts superb gorges in the Borne massif.

The Gorges du Chassezac are overlooked by the medieval village of La Garde Guérin.

    The rock, a porphyroid granite, is very nice and well polished in the bottom of the gorge. In the photo below, a decimetric vein intersects a granite with multi-centimetric potassium feldspars.

On detailed observation, the rock shows grey quartz which is clearly distinguishable from white feldspar. The latter is represented by crystals of two sizes: small multi-millimetre crystals (mainly plagioclase?) and multi-centimetre crystals of potassium felspar. The dark minerals are biotite and few amphibole.

The massif is flattened under the Triassic erosion plain, which is clearly visible under the Garde Guérin:

   The village lies on an arkosic sandstone bed, a product of the weathering of granite.

In the background, behind the village, the Mont Lozère massif dominates the landscape to the southwest.

The two massifs of the Borne and Mont Lozère are two parts of the same late-Hercynian massif, cut and displaced by a north-south oriented senestial strike-slip fault, clearly visible on the map of France:

Extract from the BRGM 1/1000 000 geological map of France.

The Cévennes are mainly composed of the "Schistes des Cévennes" (bo on the map), metamorphosed under the conditions of the beginning of the GreenSchist facies, and two large granitic massifs (red with white crosses), emplaced 305Ma ago: the Massif de l'Aigoual-St Guiral-Liron (in the South) and the couple Mont Lozère - Borne (in the North). These massifs are surrounded by an aureole of contact metamorphism. The whole is separated from the Languedoc plain in the South-East by the Cévennes Fault.

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