Abstract The Late Cretaceous magmatism in Madagascar is correlated with the break-up between Madagascar and Greater India, with a presumed track of a hotspot from Madagascar towards the Marion Island and with an anoxic event in the Late Cretaceous. The lava succession and associated dyke swarms and sills of western Madagascar (Mailaka area) represent a volumetrically important area of the igneous province, where dykes with random orientation, several igneous intrusions and a flood basalt to rhyodacite sequence do occur. The magmas have a tholeiitic and weakly alkaline affinity. Using plagioclase separates, we obtained two plateau 40 Ar/ 39 Ar ages, and an inverse isochron age statistically indistinguishable, ranging from 92.9 ± 3.8 to 91.2 ± 1.3 Ma (2 σ ). These ages indicate that tholeiitic and alkaline rocks were erupted in the same age span. In addition, these ages are close to the Cenomanian–Turonian (C–T; 93.9 ± 0.2 Ma) boundary and are indistinguishable from the U–Pb ages available for the capping rhyodacitic unit of the Mailaka lava succession. A filtered compilation of eight ages for northern and central-western Madagascar rocks suggests a duration for the magmatic activity in this part of Madagascar province of the order of c. 3 Ma. If the western Madagascar magmatism is plume related, the plume head would need to have been located near the Mailaka area at c. 93 Ma. The geochemistry of the mafic lavas and dykes of western Madagascar is barely distinguishable from mid-ocean ridge basalt (MORB), with an increasing crustal contamination towards the evolved rocks, and does not constrain input of typical components derived by plume magmatism.

Campi Flegrei is a densely populated active volcanic field. Two major explosive volcanic events have led to the formation of nested calderas. Detailed stratigraphy of the volcanic rocks outcropping in part of this area contributes toward a better understanding and definition of the volcanic hazard. Our research activity focuses on the southwestern sector of Campi Flegrei including Procida Island. This area is particularly suitable for stratigraphic reconstruction due to the thick pyroclastic sequences exposed on the coastal cliffs. These sequences include several paleosol horizons and substantially represent the products of all the volcanic activity of Campi Flegrei. The onset of volcanic activity in this area is represented by products related to the activity of scattered vents of unconstrained age. From 74 to 55 ka, they were mantled by products erupted in the nearby island of Ischia. Circa 39 ka, the Campanian Ignim-brite eruption occurred in the Campi Flegrei area, producing a large caldera. A thick succession of welded pyroclasts, lithic breccias, and associated ash- and pumice-flow deposits was emplaced in the proximal area. The local activity resumed at 19–17 ka with the formation of monogenetic volcanoes. A phreatoplinian eruption (Neapolitan Yellow Tuff) occurred at 15 ka, which produced a second, nested caldera. Stratified yellow tuff volcanoes, ranging in age between 9 and 5 ka, developed along the Neapolitan Yellow Tuff caldera boundary. Minor tephra layers testify to the final explosive activity vented in this area.

Late Cenozoic volcanic rocks on the island of Sardinia are mildly alkaline-transitional lavas, dominantly hawaiites, mugearites, and transitional basalts with minor phonolites and trachytes, which form ∼80% of the entire sample population. Tholeiitic basaltic andesites form the remaining 20% of the analyzed rocks. The oldest lavas, the ca. 6.6–4.4 Ma radiogenic Pb volcanic group, are in southern Sardinia; they have geochemical characteristics very similar to most Circum-Mediterranean Anorogenic Cenozoic Igneous Province rocks. After a gap of ∼0.5 m.y., volcanism occurred in central and northern Sardinia, from ca. 3.9 to ca. 0.1 Ma. These products, the unradiogenic Pb volcanic group, are geochemically very different. Their geochemical characteristics (relatively high SiO 2 , low CaO, and CaO/Al 2 O 3 , relatively high Ni, relatively low high field strength elements, low heavy rare earth elements, high Ba/Nb and La/Nb, slightly high 87 Sr/ 86 Sr, and unradiogenic 143 Nd/ 144 Nd and 206 Pb/ 204 Pb ratios) are considered to be derived from an orthopyroxene-rich lithospheric mantle source. The origin of this enrichment in orthopyroxene is a consequence of SiO 2 -rich melt derived from delaminated and detached ancient lower continental crust reacting with mantle peridotite. The presence of two distinct groups of rocks (unradiogenic Pb volcanics and radiogenic Pb volcanics) in a very close geographic position is related to the existence of a lithospheric discontinuity running roughly E-W in southern Sardinia.

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