Geochemical clustering reveals cryptic eruptions and tephra correlations from Antarctic fumarolic ice-cave archives

Abstract Volcanic deposits preserved within Antarctic fumarolic ice caves provide rare access to sub-ice eruptive records hidden beneath the ice cap. Here we present the first integrated textural, petrological, and geochemical characterisation of 21 tephra samples from three summit ice caves at Mount Melbourne (Northern Victoria Land, Antarctica). Major and trace-element glass compositions, combined with published datasets, were analysed using multivariate statistical workflows. Dimensionality reduction and clustering identified a distinct compositional group with no known equivalent in the existing Mount Melbourne record, suggesting that at least one previously unrecognised Holocene eruption occurred within the investigated Fumarolic Ice Caves. Correspondence between Fumarolic Ice Cave deposits and volcanic signatures in marine sediment, englacial sequences, and other proximal-distal records refined Mount Melbourne’s eruptive history and strengthened tephra correlations across archives. More broadly, sub-ice tephra archives can reveal hidden eruptive histories relevant to volcanic hazard assessment in polar regions.