Fig. 1

a Simplified tectonic map of the Aar Massif (modified after Schmid et al. 2004). Traces of cross sections A–A′′′ (Susten pass), cross sections B–B′′′ (Reusstal), cross section C–C′ (Tödi) and the study area (red polygon) are highlighted. Inset modified after Schmid et al. (2004). b Stereographic projection shows poles to bedding (black dots, 227 measurements) and axes to early folds (black crosses, 8 measurements) from the sedimentary cover of the eastern Aar Massif (Schmidt, lower hemisphere). The mean easterly axial plunge of \(070^{\circ }/10^{\circ }\) (red circle, plunge-azimuth/plunge) represents a cylindrical best fit through all poles to bedding. c Cross section B–B′′′ (in part after Brückner and Zbinden 1987; Pfiffner et al. 2011)