Aroley Formation
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The Couches de l’Aroley (short: Aroley Formation) are a sedimentary formation deposited during the Early Cretaceous (Barremian to Aptian). They consist of calcitic schists with dolomite clasts interbedded with finegrained conglomerates. The whole sequence is about 100 m thick.[1]
Couches de l’Aroley | |
---|---|
Stratigraphic range: Barremian | |
Type | Geological formation |
Unit of | Valais trilogy |
Underlies | Couches des Marmontains |
Overlies | Brèches du Grand Fond Group |
Thickness | Averaging 100 m (330 ft) |
Lithology | |
Primary | Calcitic schist |
Other | Fine conglomerate |
Location | |
Coordinates | 45.696144°N 6.734438°E / 45.696144; 6.734438 |
Region | Savoie |
Country | France Switzerland |
Type section | |
Named for | Plan Aroley |
The Couches de l’Aroley are the lowest of the three post-rift sequences deposited in the Valais ocean. It overlies syn-rift sequences of the Brèches du Grand Fond Group.[2]
The Aroley Formation can be found within the following nappes:
- External Valais
- Moûtiers unit
- Roc de l'Enfer unit
- Petit St. Bernard unit
- Internal Valais
- Versoyen unit
The type locality is the Massif de la Pierre Avoi, in Saxon, Valais, Switzerland. The formation is named after a "Plan Aroley" which lies below the Pierre Avoi. It was first described by Rudolf Trümpy 1952.[3]
The Couches de l’Aroley can be correlated with the Klus Formation and the Tristel Formation found in eastern Switzerland, the Engadin window and the Tauern window.[2][4]