Tertiary-quaternary volcanism and tectono-magmatic evolution in Italy

Tertiary-Quaternary volcanic provinces in Italy can be related to two main tectono-magmatic associations: a) Orogenic, subduction-related suites and b) Anorogenic, intra-plate suites. Space-temporal distribution and magmatic affinity of the Orogenic suites can be best accounted for by a single subduction process, dating back at least since Late Eocene, beneath the Paleo-European continental margin, and migrating southeastward with distinct features through time. The Eocene-Oligocene subduction phase, giving rise to the Sardinia-Provence volcanism (mostly calcalkaline), was characterized by moderate steepening of the northwestward-dipping Ionian oceanic lithosphere, which resulted in the opening of the Ligurian-Balearic oceanic basin and the southeastward drifting of the Sardinia-Corsica block. The subsequent Neogene-Quaternary subduction, giving rise to the peri-Tyrrhenian volcanism (calcalkaline to shoshonitic and ultrapotassic products, along the Aeolian arc and the Roman Magmatic Province), became increasingly passive and was characterized by accentuated slab sinking and roll-back, ultimately resulting in the interarc opening of the Tyrrhenian Basin. Anorogenic volcanic provinces are mainly represented in Veneto (Paleogene), Etna-Iblei-Sicily Channel (Late Miocene up to Present) and Sardinia (Pliocene-Quaternary). In both Veneto and Sicilian districts, resting on the Adriatic-African lithosphere, volcanics mainly consist of relatively undifferentiated magmas from tholeiites to Na-alkali basalts, basanites and nephelinites. The Sardinian volcanism produced comparatively more potassic magmas: from subalkaline basalts, alkali basalts/trachybasalts to basanites, locally associated with rhyolitic and phonolitic differentiates. The relatively high geothermal regime and the ubiquitous presence of specific geochemical components (HIMU) in all these volcanic provinces, irrespective of their belonging to African or European domains, lend support to the existence of a Cenozoic mantle plume supposed to extend from Eastern Atlantic to Central Europe and Western Mediterranean.