Aarmassif

The Aarmassif is part of the Helvetic zone of the Alps, which consists of material originally from the European tectonic plate.

The Aarmassif has lithologies common for Paleozoic basement rocks all over Europe, deformed and metamorphosed during the Variscan orogeny.

Other places, where the European basement crops out in the Helvetic zone, are the mountain chains of the Massif des Écrins and of Mont Blanc in the French and Italian Alps.

During a late phase in the Alpine orogeny in the Tertiary the Aarmassif was uplifted in the form of a large elongated dome structure.

The overlying limestones of the Helvetic nappes now have a very high dip angle, forming a ridge that appears at the Eiger and south of the Jungfrau mountain.