Couches de l’Aroley
Stratigraphic range: Barremian
Pierre Avoi is the type locality of the Aroley formation
TypeGeological formation
Unit ofValais trilogy
UnderliesCouches des Marmontains
OverliesBrèches du Grand Fond Group
ThicknessAveraging 100 m (330 ft)
Lithology
PrimaryCalcitic schist
OtherFine conglomerate
Location
Coordinates45°41′46″N 6°44′04″E / 45.696144°N 6.734438°E / 45.696144; 6.734438
RegionSavoie
Country France
  Switzerland
Type section
Named forPlan Aroley

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]

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]

References

  1. ↑ Loprieno, Andrea. "earth.unibas.ch/tecto/research/Diss_Loprieno_2001_small.pdf" (PDF). Archived from the original (PDF) on 6 March 2016. Retrieved 21 February 2013.
  2. 1 2 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.
  3. ↑ "Couches de l'Aroley". Lithostratigraphisches Lexikon der Schweiz.
  4. ↑ 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.{{cite book}}: CS1 maint: multiple names: authors list (link)
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