Adding pieces to the puzzle of the Western Tethys Oceanic Basin structure: the architecture of the Inzecca Unit in the Noceta-Vezzani area (Alpine Corsica, France)

The Middle to Late Jurassic, high-pressure metamorphic ophiolites of Inzecca Unit are well exposed in the Noceta-Vezzani area of Alpine Corsica. These metaophiolites were studied by using a multidisciplinary approach to reconstruct the architecture of the oceanic sector from which they derived. The collected data indicate that this oceanic crust consists of a mantle metaperidotites and metaophicalcites, both covered by massive or pillow metabasalts with or without a layer of ophiolite-bearing metabreccias. The field evidence indicates that the metaperidotites were exposed at the sea bottom and then covered by metabreccias and metabasalts. The metabasalts are intruded by plagiogranite dikes representing the last magmatic event referred to by U/Pb dating at the Kimmeridgian-Oxfordian. The metaophiolites were then covered by Early Cretaceous, hemipelagic sediments represented by metaradiolarites and by the calcschists of the Erbajolo Fm. Overall, all the features of these metaophiolites suggest its origin in an ultra-slow spreading ridge. In this frame, the origin of this ophiolite sequence is discussed, and its characteristics are compared with analogous examples from other sectors of the Alpine-Apennine belt.