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The space-time architecture variation of the shallow magmatic plumbing systems feeding the Campi Flegrei and Ischia volcanoes (Southern Italy) from halogen constraints

Balcone-Boissard Hélène 1 , Boudon Georges 2 , Zdanowicz Géraldine 1,2 , Orsi Giovanni3 Webster Jim 4 , Civetta, Lucia3 , D'Antonio, Massimo3 , Arienzo Ilenia5

  • Affiliations: 1 ISTeP - Sorbonne Université, CNRS, 4 place Jussieu 75005 Paris, France 2 Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France 3 Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, Università degli Studi di Napoli Federico II, Via Vicinale Cupa Cintia 21, 80126 Napoli, Italy 4 Department of Earth and Planetary Sciences, American Museum of Natural History, Central Park West at 79th St., NY, NY 10024-5192 USA16 5 Istituto Nazionale di Geofisica e Vulcanologia, Sezione Osservatorio Vesuviano, Via Diocleziano 328, 80124 Napoli, Italy

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 219

  • Programme No: 3.10.18

  • Theme 3 > Session 10

Abstract

Understanding the architecture of the magma plumbing system and the conditions of magma storage before an eruption is crucial for managing volcanic crises. This text uses chlorine as a geobarometer for potassic alkaline magmas at the Campi Flegrei volcanic complex to determine the depth of fluid-melt equilibration. The results from explosive eruption fallout deposits reveal multiple equilibration zones at different depths over time, including shallow magma storage. For various representative eruptions (Agnano Monte Spina, Pomici Principali, Astroni 6, and Monte Nuovo), pressure estimates range from 65 to 115 MPa. In comparison, the pressure for the Cretaio eruption (Ischia Island) is about 140 MPa. The pressures for the two largest eruptions, the Campanian Ignimbrite and the Neapolitan Yellow Tuff, show a shallow low-volume domain (~40 MPa) for the Plinian phase of the Campanian Ignimbrite and a deeper reservoir (~130--165 MPa) for the Neapolitan Yellow Tuff. These shallow pressures are interpreted as corresponding to transient magma apophyses, whose eruption was facilitated by tectonic stresses, crustal rheology, and volatile exsolution. The approach using chlorine to investigate volcanic plumbing systems is applicable to all alkali-rich magma systems.