Fig. 8

Thin section observations from the Adula Nappe basement. All sections are parallel to the stretching lineation of the Leis Phase. a Strongly foliated K-feldspar augen gneiss. Sinistral shear sense (top-to-the-west) is indicated by large quartz-feldspar aggregate forming a σ-type porphyroclast system. Width of thin section: 4.7 mm; crossed polarizers. b Chlorite-bearing micaschist. Spaced foliation of the Leis-Phase is defined by horizontal cleavage domains consisting of chlorite aggregates. Oblique orientation of white mica grains in mica-rich microlithons represents cleavage of the earlier Zapport-Phase, kinked by the Leis Phase. Width of thin section: 1.7 mm; plane-polarized light (left) and crossed polarizers (right). c Garnet bearing micaschist. σ-type garnet porphyroclast in a matrix of white mica, quartz and epidote indicates top-west shear sense of Leis phase. Width of thin section: 6.9 mm; plane-polarized light (left) and crossed polarizers (right)