The Dora-Maira Massif

Shaped as an “ellipsoid” of about 70 × 25 km, the Dora-Maira Massif is the crystalline basement of the Cottian Alps. It consists of an upper complex formed of pre-Carboniferous metasediments and metabasites, and a lower complex composed of (Permo)-Carboniferous metasediments. Both complexes contain meta-intrusives of granitic to dioritic composition, which are mainly regarded as Variscan. The sedimentary protoliths in the pre-Carboniferous basement are represented mostly by pelites with subordinate, more or less dolomitic limestones, whereas coarser clastic facies predominate in the (Permo)-Carboniferous cover. The Mesozoic sequence overlying the massif is similar to that of the other Penninic units.