Fig. 1

a Location of the study area. b Geological map of the study area compiled on the basis of maps by Bearth (1978), Thélin (1987), Sartori and Thélin (1987), Escher (1988), Steck et al. (1999), Sartori et al. (2006), Genier et al. (2008), Gabus et al. (2008a), Marthaler et al. (2008), Sartori et al. (2011) and own observations. Legend covers units of the Bernard nappe complex only. Zircon U–Pb dating results from this study, from [1] Bussy et al. (1996a), [2] Bussy et al. (1996b), [3] Genier et al. (2008) and [4] Gauthiez et al. (2011) are presented in rectangles. For meta-igneous rocks intrusion ages (in Ma) are given, whereas maximum deposition ages (in Ma) are given for metasediments. Ar/Ar and K/Ar ages (in Ma) from white micas forming the main foliation in the crystalline basement (Soom 1990; Markley et al. 1998) are also given