- 1Department of Earth, Environmental and Resources Sciences, University of Naples Federico II, Napoli, Italy (Presenting Author: pooria.ebrahimi@unina.it)
- 2Department of Earth and Geoenvironmental Sciences, Università di Bari “Aldo Moro”, Bari, Italy
- 3School of Science and Technology, Geology Division, University of Camerino, Camerino, Italy
- 4Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
Campi Flegrei caldera is an active volcanic system in southern Italy. The caldera was formed by the collapses associated with the Campanian Ignimbrite (CI; 40 ka BP) and the Neapolitan Yellow Tuff (NYT; 15 ka BP) eruptions. After the NYT, three volcanic epochs (i.e. 15-10.6, 9.6-9.1 and ~5.5-3.7 ka BP) of mainly mild to moderate explosive volcanic activity occurred. No effusive eruption has been documented in the first epoch, unlike Epochs 2 and 3. Due to their impact, the explosive eruptions at Campi Flegrei have been well studied over the years, but there are few studies on the lava domes/flows in the literature. Moreover, the shift in the eruption style during an eruption at Campi Flegrei has never been investigated by the scientific community. The infrequent observable eruptions of highly viscous and silicic alkaline lavas have hampered understanding of their mechanism as well. To bridge this knowledge gap, we studied the explosive and effusive products of Accademia eruption that followed the uplift phase after the Plinian eruption of Agnano-Monte Spina (4.55 ka BP). A fieldwork was carried out to distinguish the eruptive sequence and the pre-eruptive topography, and collect samples. Thin sections were prepared and observed under an optical microscope for petrographic characterization. The samples were also analysed with X-ray fluorescence (XRF) spectroscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The fieldwork data, petrological characterisation and geochemical analysis were used to understand: (1) the pre-eruptive topography; (2) the volume of the eruption; and (3) the geochemical evolution, crystal size distribution and viscosity of the eruptive products. Our work aims to improve the knowledge about the transition from an explosive to an effusive event and, in general, the significance of effusive eruptions during resurgence phases at Campi Flegrei.
How to cite: Ebrahimi, P., Morgavi, D., Natale, J., Arzilli, F., Di Fiore, F., and Petrosino, P.: Unravelling the processes behind the explosive to effusive transition during the ~4.3 ka Accademia volcanic eruption of Campi Flegrei, southern Italy, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13759, https://doi.org/10.5194/egusphere-egu25-13759, 2025.
