The Solfatara Magmatic-Hydrothermal System Geochemistry, Geothermometry and Geobarometry of Fumarolic Fluids

Solfatara volcano is situated close to the center of the Campi Flegrei calderawhich, in the past, has alternatively experienced phases of resurgence andsubsidence, traditionally indicated with the term bradyseism.Ludovico Sicardi (1895-1987) was an Italian scientist, who carried outpioneering studies on the Solfatara and other Italian volcanoes (Vesuvius,Stromboli, Vulcano, Panarea, Salina, and Etna), developing innovativeinstruments and methods to sample and analyze volcanic gases (Calabreseet al. 2020). He wrote several papers on the Solfatara of Pozzuoli, one ofwhich, in Italian, was published on the Bulletin Volcanologique in 1956. Inthat paper, he noted that among the numerous craters of the Campi Flegrei,on the Gulf of Naples, that of the Solfatara of Pozzuoli is the only one thathas probably preserved an uninterrupted fumarolic activity for at least twomillennia. In 1538, a few kilometers away, a new volcanic vent opened andcreated its edifice in 48 hours. It is known as Monte Nuovo and reaches anelevation of 140 m, but the only remnant of that eruptive episode of such ashort duration are some weak fumarolic emissions. The fumaroles of theSolfatara of Pozzuoli, on the other hand, reveal a truly unusual persistence,even if the thermal level of the exhalation is not excessive, since thealternation of different phases of activity is quite common in volcanic centers(Sicardi 1956).