Timing of magmatic processes at Campi Flegrei Volcanic Complex

The Campi Flegrei caldera (CFc; South Italy) is one of the most dangerous volcanic areas on Earth, due to its explosive character and the occurrence of high-magnitude eruptions. The main purpose of this research project is to investigate pre-eruption magmatic processes at CFc, and especially mingling/mixing processes among magmas with variable geochemical and isotopic characteristics. As a major goal, we propose to perform a detailed investigation on the Sr-isotopic characteristics of feldspar and clinopyroxene separated from selected volcanic rocks representative of both large- and small-volume eruptions of CFc. The Sr-isotope analyses will be carried out on both single and microdrilled portions of large phenocrysts, in order to identify the compositional features of magmatic endmembers and better assess the role of pre-eruption mixing processes. The selected CFc eruptions are: large catastrophic caldera-forming eruptions such as the Campanian Ignimbrite (ca. 39 ka) and Neapolitan Yellow Tuff (ca. 15 ka), as well as the Pomici Principali (ca. 12 ka) and Astroni 6 (ca. 4.23 ka). Diffusion chronometry studies will be carried out on the same phenocrysts (Sr and Ba in feldspars, Mg and Fe in pyroxene), in order to constrain the residence times of crystals prior to the selected eruptions.