Deutsch: Siviez-Mischabel-Decke
Français: Nappe de Siviez-Mischabel
Italiano: Falda Siviez-Mischabel
English: Siviez-Mischabel Nappe
The Siviez-Mischabel Nappe is a Middle Penninic tectonic unit of the Western Alps. It is made up of a crystalline basement with rocks of sedimentary and magmatic origin (Proterozoic to Ordovician), covered by a typical Briançonnais sedimentary cover. A Permian metagranite (Randa Orthogneiss) intruded the crystalline basement and the Permian cover. The sedimentary cover includes Permian to Triassic formations, completed by Jurassic to Eocene formations only in the normal limb of the nappe between Zermatt and the Val d’Anniviers, especially well developed in the Barrhorn region. Further west, the sedimentary cover is detached at the level of the Middle Triassic evaporites and form the Préalpes Médianes Rigides.
Siviez (VS)
Mischabel-Decke = nappe des Mischabels (Zimmermann 1955), zone du Mischabel [sic] (Bearth 1963), nappe des Mischabel (Burri 1983), nappe de Siviez-Mischabel (Escher 1988, Gouffon 1993, Sartori et al. 2006), Falda Siviez-Mischabel (Dal Piaz et al. 1992a), Siviez-Mischabel Nappe (TK500, Gouffon et al. 2024)