Skip to content

The petrology and chemostratigraphy of the Vitafumo and Miliscola tuff-cones: a key to the pre- and syn-eruptive processes during the ancient, pre-caldera stage of the Campi Flegrei volcanic field (southern Italy)

Lorenzo Fedele 1, Claudio Scarpati1, Ileana Santangelo1, Annamaria Perrotta1, Federica Güll1, Paul Cole2, Raffaello Cioni3, Claudia D'Oriano4, Mattia De'Michieli Vitturi4, Federica Pardini4, Gilda Risica4, Fabio Speranza5

  • Affiliations: 1 Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, Università degli Studi di Napoli Federico II, Napoli, Italy; 2 School of Geography, Earth and Environmental Sciences - Faculty of Science and Engineering, Plymouth University, Plymouth, United Kingdom; 3 Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Firenze, Italy; 4 Istituto Nazionale di Geofisica e Vulcanologia (INGV) -- sezione di Pisa, Pisa, Italy; 5 Istituto Nazionale di Geofisica e Vulcanologia (INGV) -- sezione di Roma, Roma, Italy 

  • Presentation type: Poster

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

  • Poster Board Number: 27

  • Programme No: 1.7.14

  • Theme 1 > Session 7

Abstract

The monogenetic volcanoes of Vitafumo and Miliscola emplaced some of the oldest deposits of Phlegrean volcanism, cropping out along the SW border of Campi Flegrei caldera. The two edifices formed one shortly after the other as the products of explosive eruptions emplacing alternating fallout and pyroclastic density current deposits. The juvenile fractions from the two successions were sampled throughout the entire stratigraphic sequences (up to 130 and 50 m thick, respectively for Vitafumo and Miliscola), which allowed for a complete chemostratigraphic investigation. This offered a unique opportunity to reconstruct the architecture of the plumbing systems of ancient Phlegrean volcanoes, whose study is generally obscured by two caldera collapses, abundant cover by younger deposits and intense urbanisation. Vitafumo and Miliscola juvenile clasts appear remarkably crystal-poor, the older Vitafumo volcano being slightly crystal-richer and featuring microphenocrysts/microglomerocrysts of sanidine and plagioclase mainly, while Miliscola pumice clasts are aphyric and display a glassy groundmass with variable amounts of sanidine microlites. Compositions are trachytic and in line with the generally strongly evolved Campi Flegrei pre-caldera products, with Miliscola samples being slightly less evolved as indicated by lower SiO2, Rb, Zr and Nb and higher TiO2, Fe2O3tot, CaO, Sr, Ba and V. No chemostratigraphic trends are apparent throughout the two pyroclastic sequences. These preliminary results suggest that in both feeding systems magma accumulation had allowed for extensive differentiation (likely accompanied by volatile enrichment) and homogenisation, supporting the idea that reservoir growth processes prevailed during the period preceding the caldera-forming eruptions at Campi Flegrei.