strati.ch - Lithostratigraphic Lexicon of Switzerland

Representation and status

Color CMYK: N/A
Color RGB: R: 241 G: 239 B: 237

Rank: tectonically bounded lithostratigraphic unit
Validity: Unit is in Use
Status: informal term

Nomenclature

Deutsch: Gornergrat-Decke
Français: Nappe du Gornergrat
Italiano: Falda del Gornergrat
English: Gornergrat Nappe

Origin of the Name: Gornergrat (VS)

Historical Variants: Trias des Gornergrates = Gornergrat-Zone (Bearth 1953), Trias des Gornergrates = Normale Triasbedeckung des Altkristallins der Monte Rosa Teildecke (Rutsch et al. 1966), Gornergrat complex (Steck et al. 1979), Gornergrat-Serie (Bl. Randa, Müller 1983), Gornergrat zone (Lacassin 1984), Gornergrat Zone (Rubatto & Gebauer 1999), Gornergrat unit (Froitzheim 2001, Engi 2001, Ellis et al. 2016), Gornergrat nappe (De Meyer 2007), Gornergrat nappe = Gornergrat unit (Steck et al. 2015), Gornergrat-Decke (Bl. Saas), Gornergrat Nappe (TK500, Gouffon et al. 2024)

Description

Description

Parautochton im Dach der Monte-Rosa-Decke ?+ polymetamorphic garnet-muscovite schist?

Steck et al. 2013 p.270: The sedimentary series in the Gornergrat area, formerly regarded as an integral part of the Monte Rosa nappe, have recently been recognized as an independent tectonic segment in front of the Stockhorn unit. Detailed stratigraphic and stuctural studies have recently lead the Lausanne group (lead by Albrecht Steck and Henri Masson) to identify several subunits, including the Mesozoic packages of the Cimes Blanches (Triassic? carbonate), the Gornergrat unit sensu stricto (Permotriassic, clastic), and the Tuftgrat unit (low to middle Jurassic, variable facies). Collectively, these subunits form a complexly folded wedge between the tectonically higher Zermatt-Saas unit and the Monte Rosa nappe. A detailed account of this new interpretation, based on several thesis projects, remains to be published.