Mineral-Melt Equilibria and Geothermobarometry of Campi Flegrei Magmas: Inferences for Magma Storage Conditions

The eruptions of Campi Flegrei (Southern Italy), one the most studied and dangerous active volcanic areas world, are fed by mildly potassic alkaline magmas, from shoshonite to trachyte phonotrachyte. Petrological investigations carried out in past decades on rocks provide crucial information for understanding differentiation processes its magmatic system. However, compositional features a palimpsest many acting over timescales 100–104 years, including crystal entrapment multiple reservoirs with different histories. In this work, olivine, clinopyroxene feldspar crystals related entire period Flegrei’s activity checked equilibrium combined possibly more rigorous tests than those commonly used previous works (e.g., Fe–Mg exchange between either olivine or melt), aim obtaining robust geothermobarometric estimations magmas these products represent. We applied several combinations geothermometric geobarometric methods suite minerals spanning ~59 ka 1538 A.D. compared obtained results inferred magma storage conditions estimated through methods. This mineral-chemistry investigation suggests that two prevalent sets T–P (temperature–pressure) conditions, here referred as “magmatic environments”, characterized investigated here. These environments ascribable mafic differentiated stationing deep shallow reservoirs, respectively, which interacted frequently, mostly during last 12 activity. fact, open-system (mixing/mingling, crustal contamination, CO2 flushing) hypothesized have occurred before could removed earlier-grown their melts. Moreover, our new indicate that, case complex systems such Flegrei’s, pre-eruptive can modify composition crystals, single method offers little chance constrain conditions. Conversely, yield agreement estimates independent studies based both petrological geophysical