Massif des Aiguilles Rouges

Representation and status

Historical Variants: Gruppe der Aiguilles Rouges = Centralmasse der Aiguilles Rouges (Gerlach 1871), massif des Aiguilles Rouges de Chamonix (Argand 1911b), massif cristallin des Aiguilles Rouges (Collet et al. 1952), Aiguilles Rouges Massiv (Büchi & Trümpy 1976), Aiguilles Rouges massif (von Raumer & Bussy 2004)

Description: Massif cristallin externe composé d'un socle anté-varisque (micaschistes et gneiss, en partie migmatitiques) et d'intrusions carbonifères. La schistosité verticale de direction N-S est recoupée par des structures NE-SW (Granite de Vallorcine et sa bordure orientale mylonitique, graben permo-carbonifère de Salvan-Dorénaz).

Subordinate units

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

p.33: The Aiguilles Rouges Massif is made up of the same rocks as the Belledonne Massif, but also includes Permian sediments. It has a relatively thin autochthonous Mesozoic–Cenozoic sedimentary cover, except in the Val d’Illiez and on the slopes of the Rhône Valley between Monthey and St-Maurice, where the series ends with an autochthonous Molasse formation, which has long been considered an internal slice of the Subalpine Molasse. The Dent de Valère Flysch outcropping north of the Dents du Midi – considered as “Ultrahelvetic” on the previous versions of the map – seems to belong to the autochthonous flysch (Jeanbourquin et al. 1992).
The Aiguilles Rouges Massif is separated from the Mont Blanc Massif by a thin band of Mesozoic sediments often referred to as the “Chamonix Syncline” in the literature. Most of these sediments can be considered as belonging to the cover of the Mont Blanc Massif, although its basal contact is strongly tectonized, even tectonic (Pfiffner et al. 2010). This band hides important tectonic contacts, not only that between both massifs and their sedimentary cover, but also a probable SW extension of the Rhône-Simplon Fault (Mancktelow 1992, Hubbard & Mancktelow 1992, Egl i & Mancktelow 2013).

Important Publications: von Raumer Jürgen F., Neubauer F. (1993) : Pre-Mesozoic Geology in the Alps. Springer Verlag, 677 pages