Multiple mantle metasomatism in central-southern Italy: Geochemical effects, timing and geodynamic implications

The regional petrological and geochemical variations observed in the Recent magmatism along the Italian peninsula are interpreted to testify to the co existence of distinct sectors of upper mantle. These are suggested to resul t from at least three compositionally and temporally distinct metasomatic e vents that affected petrologically different premetasomatic mantle sources. Geological and geochemical evidence suggests that metasomatism in the nort hern sector occurred during the Alpine subduction by introduction of a comp osition similar to the deeply subducted Dora Maira metagranites into a resi dual lithospheric mantle of upper crustal material. Metasomatic events bene ath the Roman and Neapolitan areas are younger. These are related to the ad dition of melts and fluids into a fertile asthenospheric mantle during the latest stage of the west-directed Apennine subduction of the Adria plate an d during the current northwest subduction of the Ionian sea floor.