Penninic

Representation and status

Color RGB

R: 241 G: 239 B: 237

Rank

tectonic domain

Validity

Unit is in Use

Status

valid

Nomenclature

Deutsch

Penninikum

Français

Pennique

Italiano

Pennidico

English

Penninic

Origin of the Name

Alpes pennines = partie des Alpes valaisannes située au sud de la vallée du Rhône.

Historical Variants

das penninische Deckengebirge (Alb. Heim 1922), zone pennique (Argand 1934), penninische Zone (Staub 1934), Pennides (Amstutz 1950), Falde pennidiche (Godenzi 1963), Penninische Zone (Trümpy 1974), Zona Pennidica = falde Pennidiche (Dal Piaz et al. 1992a), domaine Pennique, Penninic Domain (TK500 / Gouffon et al. 2024)

Description

Description

Die penninischen Decken stammen paläogeographisch beides aus kontinentale und ozeanische Bereiche, die ursprünglich zwischen die Europäische und die Adriatische Tektonikplatten lagen. Die interne penninische Decken wurden nach Süden subduktiert und metamorphisiert. Die kaum metamorph externe Decken wurden abgeschert und im frontalen Bereich der Alpen akkretiert. Generell wurden die nördlicher beheimateten Decken unter die südlicheren geschoben.

Hierarchy and sequence

Subordinate units

• (Internal) Penninic of Western Switzerland
• External Penninic of Central and Eastern Switzerland
• Internal Penninic of Central and Eastern Switzerland
• Oberpenninikum
• Mittelpenninikum
• Unterpenninikum

Upper boundary

Ostalpin

Lower boundary

Helvetikum

Geography

Geographical extent

Alpes occidentales et centrales (bord frontal parallèle à l'arc alpin de Briançon à Coire) et nappes préalpines.

Palaenography and tectonic

Paleogeography

Valaisan Basin , Briançonnais Terrane :

microcontinent briançonnais

, Piemont Basin

References

Definition

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

p.54: The Penninic domain comprises all tectonic units situated between the Helvetic or the Lepontic domains and the Austroalpine or the Salassic domains. It also includes units that were transported further north on the Helvetic and which are currently found as klippen on top or in front of this domain (e. g., Prealps).
The Penninic domain is subdivided into Lower, Middle and Upper Penninic subdomains that are bounded by major thrust faults. These subdivisions closely depict the structural position of the units, and also their paleogeographic origin: as a result of nappe stacking during the Alpine orogeny, the originally more southerly units were thrust onto more northerly units (see Tab. 2 and Pl. III): the Lower Penninic units are derived from the Valaisan Basin, the Middle Penninic from the Briançonnais Terrane and the Upper Penninic nappes from the Piemonte-Liguria Ocean. However, this simple model is challenged by major exceptions, for example the Upper Penninic Antrona Nappe which is situated below the Middle Penninic Monte Rosa Nappe. A metamorphic gap characterizes the Lower / Middle Penninic boundary with high-pressure blueschist facies in the former juxtaposed against greenschist facies in the latter subdomain. This case demonstrates the presence of a subduction zone where Lower Penninic and Lepontic units were subducted and subsequently rapidly exhumed (Bousquet et al. 2002).
The boundary between the Penninic and the Salassic or the Austroalpine domains corresponds, in eastern Switzerland, to the reactivated ocean-continent transition and, in western Switzerland, to the upper boundary of the subduction zone of the Piemonte-Liguria Ocean plate – together with some allochthons of Adriatic origin – below the Adriatic margin.
The original boundary between the Helvetic and the Penninic domains is the thrust fault of the Valaisan sedimentary units on top of the European continental margin sediments, referred to as the “Penninic Basal Thrust” by some authors. More generally, the “Penninic Front” refers to the outer boundary of the Penninic domain, whether it is due to the initial thrust fault or to a more recent fault, sometimes strike-slip (e. g., Rhône Fault; Cardell o et al. 2019) or normal faulting (Grasemann & Mancktelow 1993, Sartori & Epard 2011 and ref. therein).
In the Prealps and klippen of central Switzerland, the boundary between the Helvetic and Penninic domains is represented by the thrust fault juxtaposing Lower – or in rarer cases Middle – Penninic nappes (e. g., Niesen, Gurnigel, Schlieren, Wägital nappes) onto Helvetic nappes. This major thrust is highlighted by mélanges and slivers that are attributed to either the Upper Helvetic (see § 4.2.7, 4.2.10) or the Lower Penninic (Steck et al. 1999).