External Middle Penninic of Eastern Switzerland
Representation and status
- Color RGB
- R: 239 G: 237 B: 235
- Rank
- tectonic subdomain
- Validity
- Unit is not in Use
- Status
- local name (informal)
Nomenclature
- Deutsch
- Externes Mittelpenninikum der Ostschweiz
- Français
- Pennique Moyen externe de Suisse orientale
- Italiano
- Pennidico Medio esterno della Svizzera orientale
- English
- External Middle Penninic of Eastern Switzerland
- Historical Variants
-
Middle Penninic in Eastern Switzerland p.p. (TK500 / Gouffon et al. 2024)
Geography
- Geographical extent
- Prättigau-Halbfenster.
Palaenography and tectonic
- Tectonic unit (resp. main category)
- Kind of protolith
-
- tectonic
- Metamorphism
- non metamorphic
References
- Definition
-
(2024) :
Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern
p.74: In eastern Switzerland, the Middle Penninic is represented by the Tambo and Suretta basement-cover nappes and, additionally, by detached sedimentary nappes. Structurally, the Suretta Nappe occupies the core of the very large-scale north facing Niemet-Beverin Backfold that postdates nappe stacking and can be followed all the way into the Prättigau Half-Window (e. g., Schmid et al. 1990, Schreurs 1995, Weh & Froitzheim 2001). The sedimentary Schams Nappe Complex and the upper part of the Lower Penninic Tomül Nappe are wrapped around the Suretta Nappe in this mega-fold and backthrust to the southeast in an overturned position over the top of the Suretta Nappe and of the Upper Penninic Avers Nappe (see Pl. II, eastern cross-section).
In the Prättigau Half-Window, the nappe stack is upright again in that the two Middle Penninic Falknis and Sulzfluh nappes overlie the Lower Penninic Tomül Nappe and are overlain by the Upper Penninic Arosa Zone and the Austroalpine domain. The Falknis and Sulzfluh nappes and the Arosa Zone are discontinuous and often very thin. The sedimentary facies of the Falknis Nappe have close similarities with the Tasna Nappe exposed in the Lower Engadine Window (Gruner 1981). The Mesozoic strata in all these Middle Penninic units can definitely be attributed to the Briançonnais paleogeographic realm.