Oberhelvetikum

Représentation et statut

Couleur CMYK

N/A

Couleur RGB

R: 236 G: 234 B: 232

Rang

domaine tectonique

Usage

Ce terme est en usage.

Status

valide

Nomenclature

Deutsch

Oberhelvetikum

Français

Helvétique supérieur

Italiano

Elvetico superiore

English

Upper Helvetic

Variantes historiques

Hochhelvetikum (Allemann & Blaser 1951), helvetische Hauptschubmasse (Frey 1965), Helvetic Nappes [s.s.] (von Däniken & Frehner 2017), Upper Helvetic (Gouffon et al. 2024)

Paléogéographie et tectonique

Paléogéographie

plaque continentale européenne

Termes génériques

• Upper Helvetic

Type de protolithe

• tectonique

Références

Révision

Gouffon Yves (Editor) (2024) : Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern

p.38: The Upper Helvetic subdomain includes the classic “Helvetic nappes” and the overlying units of South Helvetic to Ultrahelvetic paleogeographic origin.
In western Switzerland, this subdomain includes the Wildhorn Nappe Complex, which is correlated with the Mont Chétif Nappe south of the Rhône Valley (Steck et al. 1999) and with the Roselette Nappe southwest of the Mont Blanc Massif. The Pillon and the Bulle mélange zones complete the Upper Helvetic subdomain west of the Thunersee.
In central and eastern Switzerland, the Helvetic nappes consist of two pairs of overlapping nappes, respectively the Drusberg Nappe above the Axen Nappe and the Säntis Nappe above the Glarus Nappe Complex. The two lower nappes consist mainly of Jurassic sediments, which are in places capped by Cretaceous–Paleogene sediments. Moreover, the base of the Glarus Nappe Complex consists of a thick series of Permian and Triassic rocks. The two upper nappes consist exclusively of Cretaceous and Paleogene sediments. The Tavetsch and Gotthard nappes, mainly consisting of crystalline basement, are considered to be the substratum of the “Helvetic nappes”. The sedimentary units behind the Gotthard Nappe are also part of the Upper Helvetic subdomain (Camosci and Scopi nappes, Piora-Peiden Slice Complex). Thin slivers of South Helvetic to Ultrahelvetic sediments or mélanges overlie the Drusberg and Säntis nappes (Habkern Mélange Zone, Iberg and Wildhaus mélanges, Internal Einsiedeln Slices, Fläscherberg and Liebenstein nappes).
The base of the Upper Helvetic subdomain corresponds to prominent thrusts, from west to east, with increasing displacement (see p. 32): Diablerets, Wildhorn, Axen and Glarus thrusts. In central and eastern Switzerland, as the upper nappes mentioned above have moved further north than the lower ones, their basal thrust faults become the base of the Upper Helvetic in front of the lower nappes, from west to east: Drusberg Thrust and Säntis Thrust.