OPHIOLITES ET SCHISTES LUSTRÉS CORSES: MODES DE GISEMENT, COMPARAISONS ALPINES

Abstract

Corsican ophiolites are highly comparable with those of the Alps: they comprise mantle-derived serpentinites, gabbros and basalts; no sheeted dyke complex is known. Between the basalts and/or sediments and the underlying serpentinites and gabbros, the contact is normal, i.e. not tectonical, and is often marked by a few cm to a few tens of metres of sedimentary breccias (so-called ophicalcites). Concluding, both Corsican and Alpine ophiolites derive from a slow-spreading ocean such as the Atlantic. Locally, in some parts of the Alps (e.g. Queyras) as well in parts of Corsica (Altiani-Vezzani; Cap Corse), Upper Jurassic to Lower Cretaceous tectonic activity is marked by ophiolitic detrital supply including huge ophiolitic olistoliths embedded in the Lower Cretaceous “Palombini”.