FIELD GUIDE BOOK-P27, NORTHERN APENNINE AND CORSICA OPHIOLITES: THE OCEANIC LITHOSPHERE OF THE LIGURE-PIEMONTESE BASIN AND ITS TRANSITION TO THE ADRIA CONTINENTAL MARGIN (ITALY)

The Northern Apennines and the Alpine Corsica are characterized by well preserved examples of Jurassic ophiolite sequences and their related sedimentary cover. These ophiolite sequences are considered remnants of the Ligure-Piemontesedomain, i.e. part of the western Tethys oceanic basin, developed between the Europe/Corsica and the Adria continental margins. In these sequences, the primary features of the ophiolites can be fully seen. These ophiolite sequences have been studied in detail since the ‘70s . Their petrological features and the geochemical signature of the magmatic sequences suggest that the Ligurian-Piedmont basin was as a narrow ocean, with a width no more than 400-500 km. Moreover, the ophiolites from Corsica and the Northern Apennines, as well as those from Calabria and the Alps, are characterized by very thin, reduced sequences, where the whole section is less than 700-800 meters thick. Consequently, these sequences are characterized by lithostratigraphic features that are very different from those of the “typical” ophiolite sequence defined by Penrose’s (1972) ophiolite field conference. This is also suggested by the evidence of exposure of mantle lherzolites before emplacement of basaltic flows at the seafloor, the lack of a sheeted dyke complex, and the occurrence of ophiolitic breccias over or below the basaltic flows. Another interesting feature is represented by the association of the ophiolites with granulites and granitoids in the sequences interpreted as representative of the ocean-continent transition at the Adria continental margin. All these features make these ophiolites unusual and representative of an oceanic basin whose origin, architecture and development is still under debate. This field trip focuses on the ophiolite sequences from the Northern Apennines and Alpine Corsica with the aim of providing a complete picture of the architecture of of the Ligure-Piemonteseoceanic basin and its transition to continental margins. The first and second days are devoted to the ophiolite sequences from the Internal Ligurid units, representative of the inner domain of the oceanic basin, whereas on the third day the features of the ophiolites from the ocean-continent transition will be examined in the External Ligurid units. On the fourth and fifth days both un- and metamorphosed ophiolite sequences from Alpine Corsica, will be examined