Type Geological formation Thickness Average of 500 m Other Calcitic Sandstone Region Savoie | Unit of Valais trilogy Primary Schist Country France Overlies Marmontains Formation | |
The Couches de Saint Christophe are a sedimentary formation deposited between the Late Cretaceous and the Paleogene. It is a very monotonous sequence of calcitic sandstones and black schists. These are interpreted as a turbidite sequence. The average thickness of the unit is 500 m. The Couches de Saint Christophe are a post-rift sequence that overlies the Couches des Marmontains.
The Couches de Saint Christophe occupy the following nappes:
Large outcrops of the Couches de Saint Christophe crop out north of Bourg-Saint-Maurice.
The type locality of the formation is the Val de Bagnes in the canton Valais of Switzerland. It was first described by Rudolf Trümpy in 1952. The formation is named after a chapel (46.094905°N 7.200371°E / 46.094905; 7.200371) to the northwest of Verbier.
The Saint Christophe formation can be correlated with the Sassauna Formation found in Graubünden and calcareous flysch found in the Engadine.