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Subaerial and submarine eruptions revealed by lavas and volcaniclastic rocks from the submarine flank of Mt. Etna, Eastern Sicily

Thor H. Hansteen1, Morelia Urlaub1, Felix Gross2, Alessandro Bonforte3, Séverine Furst1, Megan Campbell1

  • Affiliations:  1GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany; 2Christian-Albrechts-Universität zu Kiel, Germany; 3Istituto Nazionale di Geofisica e Vulcanologia -- Osservatorio Etneo, Catania, Italy 

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 162

  • Programme No: 2.2.26

  • Theme 2 > Session 2

Abstract

During the RV Meteor research cruise M198 in 2024, numerous volcanic and volcaniclastic rocks from the submarine Mt. Etna flanks were recovered by dredging in two areas: a) in the "Timpe area" off Aci Trezza at depths between about 750 and 600 mbsl (metres below sea level), and b) within the "Amphitheater area" off Torre Archirafi, located between the Timpe Plateau and the submarine Riposto Ridge, at depths between about 1100 and 800 mbsl. In both areas, we recovered phyric lavas with variable vesicle contents and grainsizes, some with glassy rinds, and fragments of volcaniclastic rocks consisting of crystalline rock fragments in a finer matrix, sometimes containing fresh volcanic glass particles. Glassy lava rinds and glassy matrix particles were analysed for major elements and the trace elements Cl and S using an electron microprobe. Timpe-area glasses show tholeiitic to transitional basalt compositions with high S contents of 300--800 ppm, likely reflecting submarine eruptions and re-deposition. These glasses are tentatively assigned to either the Basal Tholeiitic phase (>200 ka) or the Timpe phase (250--100 ka). Amphitheater-area glasses are mugearitic to benmoreitic, and compositionally overlap with Mt. Etna eruption products younger than 80 ka. They have comparatively low S contents of 50--250 ppm, indicating subaerial or shallow marine eruptions. Thus, the Amphitheater-area rocks may have subsided hundreds of meters, either by normal faulting, or alternatively involving gravitational sliding of Etna's SE flank