Characterization of Mt. Etna shallow feeding system by studying plagioclase textures and compositional features from the recent volcanic activity (2001-2006)

In the last decades several scientists studied the Mount Etna feeding system with the aim to understand the complex processes which magmas undergoes during ascent in pre-eruptive period. However whole rock compositions could not be able to preserve the record of complex differentiation processes, magma mixing and of the chemical changes induced by crustal contamination. Phenocrysts in volcanics rocks are commonly used to deduce processes in magma chamber due to their sensitivity to gradual or sudden modification in the chemical and physical parameters of magmas.. This study presents a systematical investigation on plagioclase textures and compositional zoning (An% and FeO) in phenocrysts of historic (pre-1971) and recent (post-1971) lavas. A texture classification is presented for the first time, and a possible interpretation of mechanism of formation proposed. MELTS simulations have been performed due to determine the plagioclase stability field in etnean lavas at different pressure and H2O dissolved conditions. The method has been applied to the eruptive period 2001-2006 with the aim to track magma ascent patterns and processes that triggered eruptions.