Magma storage and differentiation in volcanic arcs: examples from the central Aeolian arc, Italy

Abstract

The Aeolian arc is characterised by its complex geodynamic setting, with a heterogeneous mantle source and differing extents of shallow-level magmatic processes. These processes result in large within arc geochemical variations influencing the magma compositions erupted and styles of volcanism in the region distinguishing it from other volcanic arcs worldwide. Intermediate to silicic volcanism dominates during the most recent eruption stages in the central Aeolian arc, on Vulcano, Lipari and Salina after the first occurrence of rhyolitic volcanism in the Aeolian archipelago. Key eruptive centres from the central Aeolian arc characterised by alternating periods of Vulcanian to Subplinian explosive events and lava flow effusion were selected as case studies including La Fossa di Vulcano and the Lentia domes on Vulcano, the southern dome field and northern rhyolitic centres on Lipari and the Pollara crater on Salina.
This study quantitatively assesses the role of crustal contamination in the generation of intermediate and silicic magmas in the central Aeolian arc, geochemically and isotopically constrains the evolution of the La Fossa di Vulcano magmatic system and identifies the shallow conduit processes during the 1888-90 eruption of La Fossa di Vulcano. We present a stratigraphically controlled dataset to elucidate magma storage conditions, magmatic processes occurring at different levels in the subvolcanic system, and the role and extent of crustal assimilation in producing intermediate to felsic magmas since the switch to dominantly rhyolitic volcanism in the central Aeolian arc. New major- and trace-element geochemistry, stable- and radiogenic isotope geochemistry data from characteristic crustal xenoliths from the different levels within the Calabro Peloritano basement are presented to quantify the role of crustal contamination during magmatic evolution in the central Aeolian arc. This study of the central Aeolian arc quantitatively assesses the role of source and crustal contamination at arguably the most hazardous volcanoes in Aeolian arc.