Fig. 7

Photomicrographs of principal rock types. a Orthopyroxene grains partially replaced by polymineralic coronae of amphibole-biotite-ilmenite in charnockite; b massive, equigranular texture of gabbronorite formed by clinopyroxene, orthopyroxene and interstitial polygonal plagioclase and biotite; c alternating granoblastic bands of quartz and plagioclase and lepidoblastic bands of biotite, sillimanite and rare muscovite in migmatitic paragneiss and micaschist. <1 cm large Grt₁ porphyroblast (with pressure fringes) is pre- to syn-foliation; up to 1 mm large Grt₂ overgrowing the main foliation is post-kinematic; d relictic aggregates of corundum and sillimanite surrounded by polygonal cordierite in a partly migmatitic micaschist, close to the contact with the Bergell intrusion, east of Bivacco Vaninetti; e detail of a fine-grained sillimanite-garnet-bearing leucogranite; f neoblastic texture of equigranular olivine grains, inclusion-rich enstatite porphyroblasts, elongated and oriented amphibole and rare chlorite and spinel in metaperidotite at Bivacco Vaninetti. Key to abbreviations: Amp amphibole, Anth anthophyllite, Bt biotite, Chl chlorite, Cpx clinopyroxene, Crd cordierite, Crn corundum, Grt garnet, Ilm ilmenite, Kfsp K-feldspar, Musc muscovite, Ol olivine, Opx orthopyroxene, Pl plagioclase, Qtz quartz, Sil sillimanite, Spl spinel