Geological map of the Mount Avic massif (Western Alps Ophiolites)

The Mount Avic massif consists of serpentinized peridotite exposed in the southern Aosta valley (Northwestern Alps), covering an area of ca. 180 km2. The 1:10,000 scale geological map is located in the southern portion of the massif, where serpentinite is in contact with ophiolitic rocks pertaining to the Piemonte Zone, which represents the fossil Mesozoic Tethyan ocean. Southwards, ophiolites are overthrusted by the continental-derived Austroalpine Mont Glacier unit. Serpentinite consists of antigorite, magnetite, and coarse grained Ti-clinohumite, olivine, and diopside, which are reminiscent of the original mantle texture. Rodingitic mafic dykes are intruded within serpentinite; other mafic rocks, consisting of (not rodingitized) metagabbro and metabasalt with relict eclogitic minerals, occur as tectonic slices associated with serpentinite, calcschist and sulphide-rich epidosite. The map gives detailed and updated information on the structure and lithostratigraphy of the Mount Avic ophiolites, providing an insight to the mantle-crust transition of the Tethyan oceanic lithosphere.