Fig. 11

Model 2: Simplon Fault Zone geometry. a Input data on the topography surface using two sets of foliation measurements and interface points. For an optimal representation of Sm2 near the brittle detachment, the number of interface points has been increased to 4 (green dots), as less orientation data are available. b Section parallel to the extension direction showing the fault zone geometry. The older Simplon mylonites (Sm) show a domal shape while the younger fabric (Sm2) is parallel to the brittle detachment (SL). c 3D geometry of the modelled foliation field for the older (Sm) and younger (Sm2) Simplon mylonitic fabrics. In contrast to Sm2, Sm is clearly folded around the Berisal and Glishorn backfolds. d 3D geometry of the older Simplon mylonites (Sm), showing the reactivation of the pre-existent fabric S_1/2 in the core of the dome (Toce Dome) and the crosscutting relationship in the Aar culmination (to the west of the Glishorn antiform). e Wavy folds with axes parallel to the extension direction affecting the brittle detachment. B Berisal synform, G Glishorn antiform, SL Simplon Line, Sm2 younger ductile-to-brittle mylonitic foliation related to the SFZ, Sm older ductile mylonitic foliation related to the SFZ, S _1/2 pre-existent regional fabric associated to the D1–D2 deformation phase