Gotthard-Decke

Representation and status

Color CMYK

N/A

Color RGB

R: 241 G: 239 B: 237

Rank

nappe

Validity

Unit is in Use

Status

valid

Nomenclature

Deutsch

Gotthard-Decke

Français

Nappe du Gothard

Italiano

Falda del Gottardo

English

Gotthard Nappe

Origin of the Name

Gotthardpass = Passo del San Gottardo (TI)

Historical Variants

Gotthard-Massiv auct., massif du Gotthard (Argand 1911b), Gotthardmassiv (Bosshard 1925), massiccio del San Gottardo (Godenzi 1963), nappe du Saint-Gotthard, massif du Gothard (Trümpy 1970), Gotthardmassiv = Gotthard-«Massiv» (Büchi & Trümpy 1976), Gotthard massif (Mercolli et al. 1994), Gotthard-«Massiv» = Gotthard-Decke = Gotthard-Einheit = Gotthard Unit (Labhart 2005), Gotthard Nappe (Berger et al. 2017, Gouffon et al. 2024)

Description

Description

Berger et al. 2017 p.62: "The prominent geographic position of the Gotthard region as one of the preferred north–south connections across the Alps has attracted geologists and naturalists for centuries. Different tunnel projects have produced a large amount of reports on the lithological, tectonic and geotechnical characteristics of the rocks of this area. Exhaustive bibliographies, in particular from a historical point of view, can be found in LABHART (1977) and in the explanatory notes of the map sheets of the Geological Atlas of Switzerland 1:25000 (LABHART 2005, WYSS & ISLER 2007, 2011, NIGGLI et al. 2008, LABHART & RENNER 2012, VÖGELI et al. 2013, BIANCONI & STRASKY 2015). Of particular interest for the lithological description of the crystalline rocks of the Gotthard Nappe are the fundamental studies of P.Niggli’s students in the first half of the 20th century (AMBÜHL 1929, WINTERHALTER 1930, HUBER 1943, NIGGLI 1944, OBERHOLZER 1955, FEHR 1956, HAFNER 1958, STEIGER 1962). Their work served as a basis for the review of MERCOLLI et al.(1994), much of which was in turn reutilised for the present map sheet. In addition to the description of the lithostratigraphic relationships, the rocks of the Gotthard Nappe have been the focus of more recent studies on the Alpine metamorphism and tectonics (see p. 94 ff.). Table 3 is taken from MERCOLLI et al.(1994) and visualises the correlation of the pre-Mesozoic rock types described in the older literature with lithostratigraphic units of MERCOLLI et al.(1994) used for the present map."

Hierarchy and sequence

Subordinate units

• Scisti di Pontino
• Goms-Zone

Palaenography and tectonic

Paleogeography

European continental plate

Tectonic unit (resp. main category)

• Gotthard

Kind of protolith

• tectonic

References

Definition

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

p.39: The Gotthard Nappe extends from Brig in Valais to Ilanz in Graubünden. Its crystalline core (former “Gotthard Massif”) consists of pre-Caledonian and pre-Variscan para- and orthogneisses and Late Variscan granitic intrusions. The sedimentary cover of this nappe varies from place to place. It was defined as the “Urseren-Garvera Zone” at the northern border of the nappe, as the “Termen Zone” and “Nufenen Zone” at the southern border between Brig and Airolo. The former zone consists of Permian sediments overlain by Triassic and Jurassic strata while the two latter zones are composed of a Triassic to Early Jurassic series. East of Airolo, the thin cover series is essentially Triassic; between Airolo and the Passo del Lucomagno, it is in contact with the Triassic of the Piora-Peiden Slice Complex, so the boundary between the two is sometimes difficult to identify. The very narrow “Goms Massif”, located near Fiesch in the upper Rhône Valley, is embedded in the Permian of the “Urseren-Garvera Zone” and can be considered as a slice or a fold of the Gotthard crystalline or as a tectonically independent small unit due to its striking affinity to the Aar Massif.