Chapter 9 Eruptive history and magmatic evolution of the island of Salina (central Aeolian archipelago)

Stratigraphic, structural, volcanological and geochemical data allow a detailed reconstruction of the geological history of the island of Salina (central Aeolian sector). Its subaerial volcanism (~244 ka to 15.6 ka) developed through six successive Eruptive Epochs interrupted by major quiescence periods, volcano-tectonic collapses and recurrent episodes of marine terrace formation during MIS 7 and MIS 5. Several stratovolcanoes were constructed by strombolian and effusive (Pizzo Capo, Mt. Rivi, Mt. Fossa delle Felci, Mt. dei Porri) to hydromagmatic and subplinian (Mt. dei Porri, Pollara) activity, with a general east-to-west shift of active vents, controlled primarily by the dominant NNW-SSE and minor NE-SW regional tectonic trends, and a progressive chemical differentiation of the erupted products from calc-alkaline basalts to rhyolites. The magma compositions and variations through time are the result of contamination of primary magmas derived from a subduction-modified mantle source with the Calabro-Peloritano lower crust and subsequent differentiation dominated by polybaric fractional crystallisation. Magma mixing and mingling processes occurred during individual eruptions. The early basalts were fed from deep reservoirs located near the crust-mantle boundary, whereas the later andesitic to dacitic and, ultimately, rhyolitic magmas originated through combined assimilation and fractional crystallisation processes in magma reservoirs at mid- to upper-crustal levels.