Carta geologico-strutturale del Montefeltro e dell’alta valle dei fiumi Savio e Tevere.

Abstract -Main stratigraphycal data and structural elements of a large area of the Apennine chain (Montefeltro and Tuscan-Romagna Apennines) are presented. The exposed deposits belong to the Ligurian, Tuscan, Umbro-Romagna and Marche-Adriatic Domains. The study has shown a complex structural evolution articulated in several deformative Neogene phases. Every tectonic phase is marked by the thrusting of an inner unit over an outer one and by the overriding of Ligurides on Tuscan and Umbro-Romagna-Adriatic units at the level of turbiditic closure facies and Argille Azzurre Fm (Lower Pliocene). In general the Ligurian thrust-sheet seal the overridings of the underlying thrust-units. A complex duplex formed, laterally bordered by transverse lines, where piggyback basins were filled both by the Epiligurian deposits and the terminal part of the closure facies units (Ghioli di letto and Argille Azzurre Fms) overriden by the Ligurian thrust-sheet.