Falda di Suretta

Représentation et statut

Index

Su, Sur

Couleur CMYK

N/A

Couleur RGB

R: 241 G: 239 B: 237

Rang

nappe

Usage

Ce terme est en usage.

Status

valide

Nomenclature

Deutsch

Suretta-Decke

Français

Nappe de Suretta

Italiano

Falda di Suretta

English

Suretta Nappe

Origine du nom

Surettahorn (GR)

Variantes historiques

Suretta-Decke (Cornelius 1932), Surettadecke (Wilhelm 1933, Staub 1934, Spillmann 1993), Suretta-Decke (Staub 1946, Schmutz 1976), Falda Suretta (Godenzi 1963), Suretta nappe (Milnes & Schmutz 1978), falda Suretta (Sciesa 1991), nappe de Suretta (Mayerat Demarne 1994), Suretta Nappe (TK500 / Gouffon et al. 2024)

Remarques nomenclatoriales

cf. Marquer et al. 1994, Marquer & Peucat 1994

Description

Description

Mittelpenninische Decke der Ostalpen, bestehend aus einem kristallinem Grundgebirge (Ortho- und Paragneise) mit seiner autochthonen Sedimentbedeckung (klastische und karbonatische Plattformsedimente).

"puissant ensemble de cristallin anté-carbonifère, avec des restes d'une couverture mésozoïque" (Trümpy 1976)

Hiérarchie et succession

Unités hiérarchiquement subordonnées

• Finestre di Lanzada

Limite supérieure

Avers-Decke: "Im Avers und im Valmalenco folgen darüber Kalkschiefer, welche ohne genaue lithologische und tektonische Trennung übergehen in inhomogene, sandig-tonig-kalkige Metasedimente, welche meta-ophiolithisches Material (Metaggabros, Prasinite, Serpentinite) und zugehörige südpenninische Sedimente (Radiolarit, Aptychenkalk, Palombini) enthalten (Montrasio 1984, Liniger & Nivergelt 1990, Liniger 1992)." (Spillmann 1993 S.14)

Géographie

Extension géographique

Andeer, Surettahorn, Piz Timun, Valle di Lei, Piz Stella, Piz Duan, Val Bregaglia, sowie Val Malenco (Lanzada-Fenster).

Paléogéographie et tectonique

Paléogéographie

terrane briançonnais :

microcontinent briançonnais

Termes génériques

• Suretta

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 Suretta Nappe also has a Paleozoic basement of para- and orthogneisses intruded by the Permian Rofna Porphyry Complex, which consists of granitoids and effusive-type magmatites (Marquer et al. 1998). Its Permian – Mesozoic cover, again in Briançonnais facies, is largely of Triassic age. Locally the Triassic is overlain by Jurassic breccias. This cover crops out as thin layers; in one instance it follows a Suretta-internal thrust fault, in other instances they are infolded into narrow synclines that were subsequently backfolded in the upper limb of the north facing Niemet-Beverin Backfold, whose axial trace runs across the Suretta Nappe (Scheiber et al. 2012).
Two small windows (Lanzada Windows), dominated by sedimentary rocks typical for the Suretta Nappe, are located in the Val Malenco and surrounded by the Malenco-Forno-Lizun Nappe (Montrasio 1984, Montrasio et al. 2005). These windows also expose some small occurrences of metagabbro and ultramafics that are correlated with the Avers Nappe.

Principales publications

Milnes Alan G., Schmutz Hans-Ulrich (1978) : Structure and history of the Suretta nappe (Pennine zone, Central Alps): a field study. Eclogae geol. Helv. 17/1, 19-33