The Mesozoic ophiolites of the Alps: a review

The Alpine ophiolites are mostly concentrated in the inner and axial sectors of the Penninic nappe pile, as slices of the Jurassic Tethyan ocean which opened between the Europe and Adria (Africa) passive margins. The ophiolitic units consist of Mesozoic metasediments and mafic-ultramafic rocks, also including slices of subcontinental mantle. Metasediments with flysch affinity and huge ophiolites are predominant in the external and internal sectors of the Penninic zone, respectively. These sequences display polyphase metamorphic signatures and related deformations of Cretaceous-Tertiary age. Mineral and/or textural relics of pre-Alpine protoliths are locally preserved in low-strain domains, hence a comparison with equivalent sections of the oceanic lithosphere from the present-day oceans may be attempted. Despite the pervasive transposition and the absence of a convincing sheeted dyke complex, the ophiolites record place to place a complete lithological sequence that is typical of the world's best preserved ophiolitic complexes.