Brèche du Collet des Rousses

Representation and status

Color CMYK

(0%,0%,0%,100%)

Rank

lithostratigraphic Formation

Validity

Unit is in Use

Status

local name (informal)

Nomenclature

Deutsch

Collet-des-Rousses-Konglomerat

Français

Brèche du Collet des Rousses

Historical Variants

Brèche du Collet des Rousses (Loubat 1968 et 1975, Antoine 1971, Fügenschuh et al. 1999, Loprieno 2001), Collet des Rousses conglomerate (Masson et al. 2008)

Hierarchy and sequence

Units at roof

• Formation de l'Aroley

Age

Age at top

• Middle Jurassic

Note about top

Dogger (Antoine 1971) or pre-Barremian (Loprieno 2001)

Age at base

• Toarcian

Note about base

Late Liassic

Dating Method

Bélemnites

Palaenography and tectonic

Paleogeography

Valaisan Basin

Tectonic unit (resp. main category)

• Sion-Courmayeur

References

Definition

Masson Henri, Bussy François, Eichenberger Marc, Giroud Niels, Meilhac Caroline, Presniakov Sergei (2008) : Early Carboniferous age of the Versoyen ophiolites and consequences: non-existence of a “Valais ocean” (Lower Penninic, western Alps). Bull. Soc. géol. Fr. 179/4, 337-355

p.341: The base of the calcschists is often characterized by one or several dm- to dam-thick layers of conglomerate, first described by Schoeller [1929] and called by Loubat [1968] and Antoine [1971] the “Collet des Rousses conglomerate”. They are formed by rounded or angular, poorly sorted, cm to dm-large pebbles, mainly limestones, in an abundant matrix that varies from a calcareous sandstone to a sandy limestone. They represent debris flows and gradually pass upwards to the normal PSB calcschists by decreasing abundance and granulometry of the detrital content. These basal layers also contain Liassic belemnites.