Fig. 3

Geological profiles across the Voirons Nappe with associated pi-poles of bedding. a Allinges section based on the electric prospect (Büchli et al. 1976, modified). Layer 1 is interpreted as a marly interval. Layer 2 (2a and 2b) is a stack of sandstone beds with interspersed marly interbeds, whereas Layer 3 (3a and 3b) is considered as an alternation of sandy and conglomeratic beds. Stratigraphic attribution of covered units is tentative. Layer 3a is the only exposed unit at the Maladière and corresponds to the Vouan Conglomerate (Grotte aux Loups exposure). b Voirons section. Quaternary deposits are not represented due to their very low thickness. Please refer to Fig. 2 for location. Bedding measurements data from the Préalpes Médianes Nappe are reported from Lower Jurassic layers (La Vudalla Fm. and Chauderon Fm.) since Triassic beds are both poorly exposed and crudely stratified. Please note that both Foron rivers are not the same, the name Foron is frequently ascribed to small rivers in this area