Schams-Deckenkomplex

Représentation et statut

Index

Sch

Couleur CMYK

(0%,1%,2%,5%)

Couleur RGB

R: 241 G: 239 B: 237

Rang

complexe de nappes

Usage

Ce terme est en usage.

Status

valide

Discussion du statut

Muntogna/Tgea da Schons, Valle di Schams, Vallée de Schams

Nomenclature

Deutsch

Schams-Deckenkomplex

Français

Complexe de nappes du Schams

Italiano

Complesso di falde dello Schams

English

Schams Nappe Complex

Origine du nom

Schams = Val Schons (GR), Hinterrheintal

Variantes historiques

Schamser Decken (Zyndel 1912, Wyss & Isler 2007), Schamserdecken (Wilhelm 1933), Falde dello Schams (Sciesa 1991), nappes du Schams (Mayerat Demarne 1994), Schams Nappe Complex (TK500 / Gouffon et al. 2024)

Remarques nomenclatoriales

cf. Schreurs 1990, Schmid et al. 1990

Description

Description

Komplex verfaltetes Deckenkomplex, das in Graubünden zwischen den nordpenninischen Bündnerschiefern und den ophiolithführenden südpenninischen Einheiten liegt und um die Front der Tambo- und Suretta-Decken herumgewickelt ist.

Âge

Âge au sommet

• Eocène

Âge à la base

• Carbonifère

Géographie

Extension géographique

Südliche Fortsetzung zwischen die Tamboalp und der Einshorn (Mayerat Demarne 1994).

Paléogéographie et tectonique

Paléogéographie

terrane briançonnais :

microcontinent briançonnais

Termes génériques

• Schams

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.75: The Schams Nappe Complex comprises a set of small nappes, composed of sedimentary sequences exhibiting large facies variations and rich in sedimentary syn-rift breccias of Middle Jurassic to Early Cretaceous age, indicating contemporaneous extension and sinistral strike-slip (Rück 1995). The mid-Cretaceous to Cenozoic post-rift sediments are very similar to those found in the Falknis Nappe. After its emplacement, this nappe complex was folded around the Tambo-Suretta pair during the Niemet-Beverin post-nappe folding (Schreurs 1995). The fact that the Schams nappes are folded around a locally near-isoclinal fold has long raised the question about the origin of this nappe complex either below the Tambo Nappe or on top of the Suretta Nappe (Schmid et al. 1990). Structural criteria clearly show that the Schams Nappe Complex has to be rooted below the Tambo Nappe (Schreurs et al. 1995). Retrodeformation suggests that the Schams nappes formerly occupied an area north of the depositional area of the Tambo and Suretta Mesozoic (Schmid et al. 1997). This is supported by facies arguments indicating that sediments in the originally northernmost paleogeographical position (now forming the Gelbhorn Nappe) suggest N-directed shedding of syn-rift breccias, and by the Subbriançonnais-type facies of the Triassic strata (Rück 1995). The Schams Nappe Complex also contains different mélanges: to the west, in the lower limb of the Niemet-Beverin Backfold, the Knorren Mélange is in contact with the Tambo Nappe, while the Areua-Bruschghorn Mélange marks the boundary with the Tomül Nappe; to the east, in the upper (overturned) limb of the Niemet-Beverin Backfold, the Martegnas Mélange is in contact with the Arblatsch Flysch belonging to the Tomül Nappe (Mayerat Demarne 1994, Schreurs 1995).

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