The history of the Campi Flegrei Magma System through time: the key to understand present and future volcanic processes

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The Campi Flegrei caldera (CFc; South Italy) is one of the most dangerous volcanic areas on Earth, due to of its explosive character and the occurrence of high-magnitude eruptions (Orsi et al., 2004). In spite of high volcanic hazard the Italian 2011 census (www.istat.it) estimates that over 1.5 million of people are currently living within the caldera and its surroundings, making the volcanic risk of the area extremely high (Orsi et al., 2004). The understanding of present unrest episodes, the definition of the present state of the magmatic system feeding active volcanoes, requires the knowledge of past pre-eruptive magmatic processes and of the relationships between them and the eruptive dynamics. For these reasons the volcanological history as well as and the geochemical and isotopic characteristic of the erupted product has been a matter of extensive scientific studies. The purpose of our project is to extend the present knowledge on the evolution of the CF magma sources, its feeding system as well as the volcanological evolution as it relates to the characterization of distinct magma batches, their source(s), evolution and interaction in this evolving magma system. By combining new geochemical (major-, trace elements) and isotopic (radiogenic 87Sr/86Sr and stable delta18O) data on separated minerals and whole rocks we aim to detect processes that precede and characterize the arrival of fresh magma batches from depth. As a second goal, we will use Ba and Sr diffusion modeling in sanidines and plagioclase phenocrysts to constrain the residence times of crystals prior to erution of (a) many small scattered and isolated eruptions within the Campi Flegrei and the shift to (b) large catastrophic caldera-forming eruptions such as the Campanian Ignimbrite and Neapolitan Yellow Tuff.