Fig. 8

a Sketch map of the Sila Massif: (1) continental unit affected by pervasive Tertiary orogenic fabrics; (2) lower crustal section (high grade metamorphic rocks), (3) Mesoraca Shear Zone, (4) intermediate crustal section (leucogranite, gabbro-diorite; metaluminous to strongly peraluminous granite and granodiorite); (5) upper crustal section of low grade metamorphic rocks. b Equal area, lower hemisphere stereonets showing structural data of the Mesoraca Shear Zone. (1) Poles of the main foliation and mineral and/or stretching lineation in migmatitic paragneiss, foliated granodiorite and mylonites. Contouring of lineation and foliation data indicated by grey and white areas, respectively; contouring interval (2%) equals the maximum of the data distribution contoured at > 16%; (2) best fit of foliation and lineation data; (3) back-rotation of the averaged mean foliation and lineation obtained by assuming a horizontal rotation axis parallel to the strike of the mean foliation (details in Liotta et al. 2008). c Melt-present deformation structures in granodiorites representing the early stages of Mesoraca Shear Zone deformation; d S/C structures indicating a top-to-the-west sense of shear in mylonites of the Mesoraca Shear Zone; e thin section scan (crossed polars) of a granodiorite involved in the Mesoraca shear zone. Quartz ribbons and porphyroclasts of quartz and feldspars locally showing core and mantle structure can be observed; f undeformed pegmatite and porphyritic dyke, intruding wall-rocks and the previously emplaced granitoids, respectively. The dyke (dated between c.290–280 Ma in Liotta et al. 2008) is exposed close to the Arvo Lake