Tectonic setting of the Susa and Lanzo Valleys Ophiolites (Western Alps)

The 1:30,000 scale geological map of the Viù Valley (∼200 km²) depicts the tectonic architecture of the Susa and Lanzo Valleys Ophiolites (SLVO), a slice of the Jurassic Ligurian-Piedmont oceanic lithosphere stacked in the Western Alps. The SLVO successions (i.e. serpentinite, metagabbro, metabasalt and metasediments) were subducted, metamorphosed under high-pressure conditions, and exhumed during the Alpine orogeny. Detailed mapping and structural analysis highlight that the SLVO underwent four deformation phases and consist of six tectonic units bounded by two first-order shear zones (i.e. Susa and Viù-Locana shear zones) and crosscut by a network of second-order shear zones (i.e. Usseglio, Margone, Lemie, Ovarda, and Cugni shear zones). The current tectonic framework was mainly established during the long-lasting exhumation-related D2 phase, characterized by a switch from early top-to-W to late top-to-E kinematics. This map details the SLVO lithostratigraphic and structural setting, improving knowledge about the ophiolites of the Alpine-Apennine subduction-exhumation system.