CARATTERI GEOCHIMICI DEL MANTELLO SORGENTE DEL MAGMATISMO NAPOLETANO: NUOVE CONOSCENZE DALLO STUDIO DELLE OFIOLITI DEL SETTORE LUCANO DELL'APPENNINO MERIDIONALE

According to this model, the oceanic crust consists of a 4 to 6 km thick igneous crust (pillow basalts, sheeted dykes and gabbroic layer, from top downward) produced by melts formed by decompression melting of ascending asthenospheric mantle, overlying a peridotite basement. Moreover, the igneous pile may be overlaid by a few hundred meters of pelagic/terrigenous sediments. During the last thirty years, the study of peridotites from the Mediterranean Area has provided a wealth of information, constraining the composition and, partially, the evolution of the Mediterranean Lithospheric Mantle. In Italy, ophiolites occur in scattered outcrops located mainly in the Alps and Northern Apennine (Piccardo et al., 2009 and references therein). In Southern Apennine, ophiolite outcrops are very rare, occurring only in southern Basilicata and northern Calabria (Beccaluva et al., 1983; Spadea, 1994) and like as olistoliths in Miocene turbidites of Cilento Group at Monte Centauino (Di Girolamo et al., 1992) in Southern Campania. Ophiolites from the Alpine and Apennine orogenic terranes are believed to represent fragments of oceanic lithosphere of the Ligurian-Piedmontese (Ligurian Tethys) basin that formed during Late Jurassic between the Europe and Adria continental blocks, following extension driven by far field tectonic forces and that were obducted on continental crust during the closure of this ocean (Bortolotti and Principi, 2005). More information on the mineralogy and geochemistry of the Mediterranean upper mantle has been derived especially from the largel