VARISCAN VOLCANISM OF CENTRAL AND WESTERN EUROPE.

The type of volcanism in Central and Western Europe clearly reflects the tectonic conditions of the time of its manifestation. Two main types of Variscan volcanism can be distinguished: spilito-keratophyre (pre-orogenic); and postorogenic calc-alkaline. The spilito-keratophyre associations are widespread in space and time and form belts related to regional faults, intraplate rifts and grabens. This reflects a tectonic regime of tension. The tectonic conditions during the time of eruption of postorogenic volcanics is quite different. They are characterized by folding, vertical movements, compression and anatectic melting in the sialic crust. Two associations can be distinguished: a late-orogenic one of monotonous acid composition, and a postorogenic or final one of bimodal composition. Refs.