Glarus Thrust

The Glarus thrust (German: Glarner Überschiebung) is a major thrust fault in the Alps of eastern Switzerland. Along the thrust the Helvetic nappes were thrusted more than 100 km to the north over the external Aarmassif and Infrahelvetic complex. The thrust forms the contact between older (Helvetic) Permo-Triassic rock layers of the Verrucano group and younger (external) Jurassic and Cretaceous limestones and Paleogene flysch and molasse.

The Glarus thrust crops out over a relatively large area in the cantons Glarus, St. Gallen and Graubünden, due to its horizontal orientation and the high local relief. Famous outcrops include those at Lochsite near Glarus (the town) and in a mountain cliff called Tschingelhörner between Elm and Flims (in the same cliff is a natural hole called the Martinsloch).