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.[1] The Couches de Saint Christophe are a post-rift sequence that overlies the Couches des Marmontains.[2]
| Couches de Saint Christophe | |
|---|---|
| Stratigraphic range: Late Cretaceous-Paleogene | |
| Type | Geological formation |
| Unit of | Valais trilogy |
| Overlies | Couches des Marmontains |
| Thickness | Averaging 500 m (1,600 ft) |
| Lithology | |
| Primary | Schist |
| Other | Calcitic sandstone |
| Location | |
| Coordinates | 45°41′46″N 6°44′04″E / 45.696144°N 6.734438°E |
| Region | Savoie |
| Country |  France Switzerland |
| Type section | |
| Named for | Chapel St. Christophe, Verbier |
The Couches de Saint Christophe occupy the following nappes:[2]
Large outcrops of the Couches de Saint Christophe crop out north of Bourg-Saint-Maurice.[2]
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°05′42″N 7°12′01″E / 46.094905°N 7.200371°E) to the northwest of Verbier.[3]
The Saint Christophe Formation can be correlated with the Sassauna Formation found in Graubünden and calcareous flysch found in the Engadine.[4]
References
edit- ^ Loprieno, Andrea (2001). "A combined structural and sedimentological approach to decipher the evolution of the Valais domain in Savoy, (Western Alps)" (PDF). earth.unibas.ch. University of Basel. Archived from the original (PDF) on 6 March 2016. Retrieved 6 June 2023.
- ^ a b c Loprieno, Andrea (2011). "The Valais units in Savoy (France): a key area for understanding the palaeogeography and the tectonic evolution of the Western Alps". International Journal of Earth Sciences. 100 (5): 963. Bibcode:2011IJEaS.100..963L. doi:10.1007/s00531-010-0595-1. hdl:20.500.11850/37751. S2CID 56379732.
- ^ "Lithostratigraphisches Lexikon der Schweiz". Retrieved 25 February 2013.
- ^ Tricart, Pierre-Charles de Graciansky, David G. Roberts, Pierre (2010). The Western Alps, from rift to passive margin to orogenic belt : an integrated geoscience overview (1st ed.). Amsterdam: Elsevier. p. 153. ISBN 978-0444537249.
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