Robust statistical analysis of an englacial tephra sequence unveils previously unrecognized explosive eruptions at Mount Melbourne (Antarctica)

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Abstract
Reconstructing the eruptive history of Antarctic volcanoes is often challenging due to limited outcrops exposure, extensive ice cover, and extreme environmental conditions. Here, we present detailed volcanological, textural, and geochemical analyses of three tephra layers (DPT 1, DPT 2, and DPT 3) from an englacial ice sequence at 2581 m asl on the southwest flank of Mount Melbourne, northern Victoria Land (Antarctica). Using robust statistical methods, including cluster analysis and data visualization approaches based on dimensionality reduction [i.e., principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE)], we identified a previously unrecognized sequence of explosive eruptions. Our findings underscore the crucial role of ice in preserving volcanic records and highlight the potential of tephra investigations to enhance our understanding of magma evolution and volcanic hazard in remote environments. The geochemical characterization, including major and trace element analyses, confirmed that the tephra layers originated from Mount Melbourne but represent three distinct eruptive events not previously documented. The DPT 1 layer is interpreted as a fallout deposit from a more intense eruption (possibly Subplinian), while DPT 2 and DPT 3 layers were produced by less energetic events occurring in close succession. Although precise dating was not possible, the stratigraphic context suggests a recent, potentially historical age for these eruptions. This study refines the eruptive history of Mount Melbourne and emphasizes the importance of englacial tephra records for understanding Antarctic volcanism.
Funding Information
  • Programma Nazionale di Ricerche in Antartide (PNRA18_00208-E)
  • Programma Nazionale di Ricerche in Antartide (PNRA18_00158-A)
  • Programma Nazionale di Ricerche in Antartide (PNRA0000019)
  • Università degli Studi di Perugia
  • Istituto Nazionale di Geofisica e Vulcanologia

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