A tephrostratigraphic approach to further understand the Campi Flegrei caldera, Naples, Southern Italy.

The Campi Flegrei is renowned for its diverse eruption activity in magnitude and chemistry over the last 50 kyr, characterised by three main periods: Pre-CI, CI-to-NYT, and post-NYT. The transition from the CI to the NYT is marked by a distinct change in end-member chemistry: products of the CI exhibit greater chemical heterogeneity and are overall more silicic (phonolitic) compared to the relatively less silicic and more alkaline (trachytic) composition of the NYT members (Tomlinson et al., 2012). This shift in eruptive product chemistry reflects a change in the underlying magmatic system over time; analysing changes in magma composition within the context of this CI-NYT sequence will help with understanding this systemic change. For instance, the CI was more chemically heterogeneous than the subsequent NYT eruption (Tomlinson et al., 2012), indicating the tapping of more chemically distinct magmas during the CI eruption. This raises significant questions such as: What changes in magma composition and conditions do we observe after these major caldera-forming eruptions? And over what timescales do these changes occur? How long does magma recharge take? These questions will be in the focus of my D.Phil.