Building a bridge between distal tephra archives and the Neapolitan volcanoes: Insights on the 130-200 ka explosive activity from the Campanian Plain

The geological evidence of ancient activity of Neapolitan volcanic sources in southern Italy is often elusive and inaccessible in the proximal areas. In fact, these deposits are part of the thick pile of volcanic products alternating with alluvial/transitional/shallow marine sediments emplaced in the Campanian Plain over the last 2 Ma, which makes them often buried deep in the subsurface. Conversely, the distal and ultra-distal archives are rich in tephra layers attributed to "unknown eruptions of Campanian or Neapolitan volcanoes". The proximal-distal tephrostratigraphic framework has recently improved for the last 110 ka but is still fragmentary or missing from MIS6 and older. With the aim of trying to build a bridge between the rich distal evidence and their possible proximal counterparts in the poorly investigated 130-200 ka time span, new data have been obtained through a multi-methodological approach (field survey, major and trace elements, Sr and Nd isotopes and 40Ar/39Ar dating) from pyroclastic units outcropping or recovered in sediment cores in the eastern and north-eastern sectors of the Campanian Plain. Our combined approach brings to light the occurrence of several eruptions, most of which are reported here for the first time. Three main eruptive events have been identified for which widespread dispersal could be hypothesised. The most recent event is the Taurano Ignimbrite (159.8 ± 2.0 ka), the type-section of which has been described at the Piano delle Crete site (Valle di Maddaloni). A previously unrecorded Plinian eruption, named San Giovanni del Palco (∼176 ka), has a southeastward pyroclastic fall distribution and a unique climato-stratigraphic position, making it a good marker for the MIS6e-6d transition. The oldest eruptive event is represented by the Moschiano Ignimbrite (∼190 ka), whose pyroclastic currents are distributed in both the northern and southern Campanian Plain. In addition to the identification of previously unrecorded eruptive events, which improves our understanding of the frequency of large-scale eruptions, our results allow for the detection of distinctive "Campi Flegrei-like" geochemical characteristics in ancient products emplaced during the Late Middle Pleistocene.