Why Mt Etna?

The Etna volcano is located in an apparently anomalous position on the hing e zone of the Apennines subduction and its Na-alkaline geochemistry does no t favour a magma source from the deep slab as indicated for the Aeolian K-a lkaline magmatism. The steeper dip of the regional foreland monocline at th e front of the Apennines in the Ionian Sea than in Sicily, implies a larger rollback of the subduction hinge in the Ionian Sea. Moreover, the lengthen ing of the Apennines arc needs extension parallel to the arc. Therefore, th e larger southeastward subduction rollback of the Ionian lithosphere with r espect to the Hyblean plateau in Sicily, should kinematically produce right -lateral transtension and a sort of vertical 'slab window' which might expl ain (i) the Plio-Pleistocene alkaline magmatism of eastern Sicily (e.g. the Etna volcano) and (ii) the late Pliocene to present right lateral transten sional tectonics and seismicity of eastern Sicily. The area of transfer of different dip and rollback occurs along the inherited Mesozoic passive cont inental margin between Sicily and the oceanic Ionian Sea, i.e. the Malta es carpment.