Silicic volcanism in the central Aeolian Islands of Lipari and Vulcano has followed a consistent pattern during the past 22,000 years. Active eruptive cycles generally began with hydrovolcanic breccias, surge beds, and ash-fall deposits. They ended with magmatic effusions that formed lava domes and short coulees. Long repose periods separated shorter active cycles. Eruptions occurred from both isolated vents located along fissures (e.g., domes of southern Lipari) and central vents with a long history of activity and repose (e.g., Fossa cone of Vulcano). The compositions of the juvenile products include leucite tephrite, trachyte, and rhyolite. The average volume of silicic products in an eruptive cycle on Lipari and Lentia was about 5 × 10 8 m 3 of juvenile magma. The repose period between major active periods was about 4,000 years. The production rate for the period of 22,000 years ago to the present was 10 5 m 3 per year. The average volume of erupted material in an active cycle at Fossa (other than the Punte Nere cycle) was about 2 × 10 7 m 3 of juvenile magma. Repose times between cycles range from 300 to 800 years. The rate of magma production for the entire Fossa cone during its 6,000-year growth was 5 × 10 4 m 3 per year. Vulcanello produced about 3 × 10 7 m 3 of tephritic to trachytic magma in the past 2,100 years, a production rate of 1.5 × 10 4 m 3 per year.

Abstract Vulcano is an active NW–SE-elongated composite volcano located in the central Aeolian archipelago. Based on available radiometric ages and tephrochronology, the exposed volcanism started at c. 127 ka and spread through eight Eruptive Epochs separated by volcano-tectonic events and major quiescent stages. Various eruptive centres and two intersecting multi-stage calderas resulted from such evolution. Vulcano geological history displays several changes of eruption magnitude, eruption styles and composition of magmas through time. Vulcano rocks range from basalt to rhyolite and show variable alkali contents, roughly increasing during time. Magmas with low to intermediate SiO 2 contents and high-K to shoshonite affinity prevail in the early Epochs 1–5 ( c. 127–28 ka), whereas intermediate to high-SiO 2 shoshonite and potassic alkaline products dominate the last three Epochs (<30 ka). This sharp increase in silicic products is related to the shallowing of the plumbing system and resulting major role of the differentiation processes in shallow-level reservoirs. Radiogenic isotope compositions are variable ( 87 Sr/ 86 Sr=0.70424–0.70587, 143 Nd/ 144 Nd=0.51254–0.51276, 206 Pb/ 204 Pb=19.305–19.759, 207 Pb/ 204 Pb=15.659–15.752, 208 Pb/ 204 Pb=39.208–39.559) as a result of both source heterogeneities and shallow-level interaction of magmas with continental crust. The compositional variations of mafic magmatism with time suggest that the source zone changed from a metasomatized, fertile, ocean island basalt- (OIB-) like mantle to a metasomatized depleted lithospheric mantle. DVD: The 10 000 scale geological map of Vulcano is included on the DVD in the printed book and can also be accessed online at http://www.geolsoc.org.uk/Memoir37-electronic . Also included is a full geochemical data set for Vulcano.

The Aeolian Island arc, emplaced on continental lithosphere, is composed of seven islands and several seamounts, which have evidence of magmatic activity from 1.3 Ma (Sisifo seamounts) to present time (Vulcano, Stromboli). The rock compositions belong to different magmatic series and show a large silica range (48–76 wt%). Calc-alkaline and high-K calc-alkaline volcanics are present in all the islands, except for Vulcano. Shoshonitic rocks are only lacking at Alicudi, Filicudi, and Salina. Potassic magmas have been erupted at Vulcano and Stromboli. The different parental magmas originated in a heterogeneous mid-ocean-ridge basalt (MORB)–like mantle wedge, variously metasomatized by subduction-related components (oceanic crust + sediments, released as either fluids or sediment melts). Trace-element and Sr-Nd isotopic ratios show clear geographical west-east variations among calc-alkaline rocks. The composition of the mantle source of Stromboli is strongly influenced by the addition of a sedimentary component recycled into the mantle wedge; it shows evidence of a higher amount (∼2%) than in all the other islands (<0.5%). Furthermore, the islands from the central sector of the arc are characterized by a higher proportion of slab-derived fluids, which promotes a higher degree of melting. In this frame, the high Pb isotopic ratios (HIMU-like [high µ–like]) of the rocks of the central and western branch of the arc are explained with the high 206 Pb/ 204 Pb carried from a fluid component derived from the dehydration of the ancient subducting Ionian oceanic crust. On the contrary, the low Pb isotope signature of Stromboli magmas is dictated by the sediment input, as for Sr and Nd isotopes. Parental shoshonitic magmas of Vulcano are generated by low melting degrees of a MORB-like mantle wedge, metasomatized by crustal contaminant with high fluids/sediment values, whereas Vulcano potassic magmas are interpreted as deriving from the shoshonitic magmas by refilling, tapping, fractionation, assimilation (RTFA) processes. At Stromboli, potassic to calc-alkaline magmas are generated by increasing melting degrees of a heterogeneous veined mantle. The involvement of K-micas in the genesis of potassic magmas (during partial melting of mantle wedge and/or subducted sediments) is also suggested. U-Th disequilibria confirm the higher fluid versus melt proportion in the central than in the western islands. At Stromboli, the 238 U excesses measured in calc-alkaline volcanics suggest a consistent addition of slab-derived fluids in the source, also promoting higher degrees of melting. The shift to the consistent 230 Th excesses in shoshonitic and potassic rocks requires dynamic melting processes capable of producing in-growth of 230 Th. Quantitative modeling suggests lower melting rates for shoshonitic and potassic rocks, which are consistent with the lower melting degree proposed for these magmas.