The protolith of the orthogneiss was once a porphyritic granitoid which was later on ( during the Variscan orogeny ) deformed plastically.
22.
It is the southernmost major tectonic feature of the British Caledonide belt, though was active again in the later Variscan orogeny.
23.
The mountain building period known as the Variscan orogeny, which occurred around 280 Ma, caused major deformation in south west England.
24.
Plate convergence that caused the Caledonian orogeny in the Silurian continued to form the Variscan orogeny in the succeeding Devonian and Carboniferous Periods.
25.
In the Pennsylvanian subperiod of the Carboniferous geological period, these rock layers were narrowed and folded as a result of the Variscan orogeny.
26.
Further collisions caused the Variscan orogeny in the Devonian and Carboniferous periods, forming the hills of Munster, southwest England, and southern Wales.
27.
The Variscan orogeny involved a complicated heterogeneous assembly of different microplates and heterochronous collisions, making the exact reconstruction of the plate tectonic processes difficult.
28.
Even earlier orogenies relevant for the ultimate formation of Europe are the Caledonian orogeny, some 400 Mya and the Variscan orogeny, some 300 Mya.
29.
The corresponding unconformity, which exists only in the western Pyrenees, belongs to an early deformation phase of the Variscan orogeny ( Breton Phase ).
30.
Arsenates and molybdates are not foreign to the Massif Central, which was mineralized in those two element groups at the end of the Variscan orogeny.
