My project is focused on fifteen eruptive products (i.e., scoriae, lava flows, lava domes, and lava dykes) erupted at Vulcano Island (Aeolian Arc, Italy) over a long period of time from 54 to 8 ka and representative of Eruptive Epochs from 5 to 8, according to the chronostratigraphy of the last geological map. I investigate both high-K calc-alkaline and shoshonitic rocks, with compositions changing from primitive basalts-shoshonites (Mg#35-60) to intermediate latites (Mg#32-54) to evolved trachytes-rhyolites (Mg#23-40), focusing on the clinopyroxene population. The architecture of the plumbing system at Vulcano Island is characterized by multiple reservoirs continuously refilled by more mafic magma in which compositionally distinct magmas pond and undergo mixing and polybaric-polythermal differentiation, before erupting to the surface. This project seeks to integrate the textural and microchemical analyses of zoned clinopyroxenes from Vulcano products with new petrological tools developed in the recent years for accurately estimating the pressure, temperature, melt-water content, and residence time of magma before eruption. The intensive variables driving the crystallization path of magmas are reconstructed through mineral-melt equilibrium and thermodynamic models, as well as barometers, thermometers, hygrometers and oxygen barometers. A new diffusion chronometry modelling named NIDIS (Non-Isothermal Diffusion Incremental Step model) allows to calculate the timescales of pre-eruptive magmatic processes in active volcanic systems in order to understand magma chamber dynamics and the triggers for volcanic eruptions.
This project is mainly focused on the importance to use different approaches and analytical methods to obtain a view of the pre-eruptive magmatic processes as larger as possible, either from micro or regional scales. I will combine microchemical analyses of zoned clinopyroxenes with new petrological tools to estimate intensive variables and residence time of magma before eruption. The main focus is the reconstruction of the lifetime history of complex compositionally zoned clinopyroxenes in order to better understand magmatic storage and pre-eruptive processes in the plumbing systems of Vulcano island. Clinopyroxene population can greatly enhance the ability to unravel complex interactions between crystals and magma mixing, preserving the timescale record of pre-eruptive processes, from magma injections and melt homogenisation to eruption-triggering events. The chemical information will be associated to the timescale modeling for the first time at Vulcano island using the NIDIS model. This model yields a novel approach to constrain the timescale of the stepwise history of crystals in the realistic scenario of diffusion chronometry at two different temperatures. The rationale of the NIDIS model can be applied to virtually any volcanic system and mineral phase paying attention to the rate of diffusion of the elements involved. The study carried out on Vulcano island will offer the opportunity to extend the petrological and volcanological outcomes to other islands of the Aeolian archipelago to elucidate whether the magmatic source and plumbing system are the same or the evolution of the islands has been driven by different petrogenetic paths. It would be also interesting to analyze the magmatism of the island arc with the intent to link its physicochemical characteristics to the geodynamic evolution of the arc setting. Our understanding on the movement of magma preceding past eruptions could advise future volcano monitoring efforts together with seismic or deformation signals and the time available for hazard evaluation and emergency planning.