Geodynamic setting
According to the ‘most popular’ models, the evolution of the Mediterranean geodynamic system during the Neogene was controlled by the dynamics of subduction in a region of complex convergence between the African and Eurasian plates (Malinverno and Ryan 1986; Faccenna et al. 1997; Guegen et al. 1998; Faccenna et al. 2004). In the central Mediterranean, the Africa and the Eurasia plates underwent several hundred kilometers of convergence since the early Tertiary. Such a convergence has been mainly achieved by north-westward dipping subduction of the Ionian-Adriatic lithosphere underneath the Eurasia plate. The Central Mediterranean subduction system was characterized by trench retreat and progressive fragmentation of the Adriatic-Ionian slab (Patacca et al. 1990; Faccenna et al. 1997; Faccenna et al. 2001; Cifelli et al. 2007a and references therein). Presently, evidences of active narrow slabs are given by subcrustal earthquakes occurring down to 90 km depth below the Northern Apennines (Selvaggi and Amato 1992; Chiarabba et al. 2009; Di Stefano et al. 2009), whereas a well defined Benioff zone down to about 670 km, reveals a direct trace of a still active process of lithospheric subduction from the Ionian foreland below the Calabrian Arc and Tyrrhenian Sea (e.g., Anderson and Jackson 1987; Selvaggi and Chiarabba 1995). Slab roll-back and the decreasing of the width of the active trench through time, resulted in the formation of curved orogenic belts, sometimes characterized by a very tight curvature (Fig. 1), together with extensional back-arc basins (Ligure-Provençal and Tyrrhenian basins) (Alvarez et al. 1974; Boccaletti and Guazzone 1974), which have been characterized by the emplacement of medium to large plutonic bodies and by a long-standing volcanic activity which continues up today (Barberi et al. 1973; Civetta et al. 1978; Serri et al. 1993).