Fig. 2

a Geological map of the Mont Morion Unit in the area of the Comba de Crête Sèche. Stars indicate the location of the studied samples. The original geological mapping was undertaken at 1:10,000 scale, using as topographic base the “Carta Tecnica Regionale”, Regione Valle d’Aosta, UTM ED 1950 coordinate system. The map has been redrawn on the georeferenced topographic map n1366 “Mont Vélan” edited by the Swiss Federal Office of Topography, “Swisstopo”. b Schematic cross-section of the Comba de Crête Sèche. Note the largely undeformed body of the Mont Morion granite, intruding partially melted gneiss and amphibolite, both being separated from the heterogeneously deformed Aroletta granite by a ductile shear zon