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The Sandy Bay caldera-forming silicic submarine eruption at Macauley volcano, Kermadec arc/Rangitāhua

Martin Jutzeler1, Catherine Lit1, Shannon Frey1, Rebecca Carey1, Yusuke Yokoyama2, Stephen Gallagher3, Shane Cronin4

  • Affiliations: 1Centre for Ore Deposit and Earth Sciences (CODES), University of Tasmania, Australia 2Atmosphere and Ocean Research Institute, The University of Tokyo, Japan 3School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Australia 4School of Environment, Auckland University, New Zealand

  • Presentation type: Poster

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

  • Poster Board Number: 78

  • Programme No: 6.2.14

  • Theme 6 > Session 2

Abstract

Macauley volcano is a submarine silicic composite volcano in the Kermadec intra-oceanic arc/Rangitāhua, north of New Zealand/Aotearoa. The volcano comprises an extensive shallow-water edifice punctured by a large submarine caldera and the small remnant of an island. The submarine slope of the volcano includes eruption-fed, giant sediment waves and older submarine landslides. The up to 100 m high cliffs on Macauley Island form the Sandy Bay Tephra (SBT), which geochemically match the submarine sediment waves and distal marine tephra, and attest of a voluminous pumice-forming silicic eruption associated with the current submarine caldera. Based on a comprehensive set of sediment core and onland samples, augmented by 14C geochronology and bathymetry and seismic reflection data, we reconstructed the eruption stratigraphy to infer vent environment and eruption and transport processes that acted during this major event. The interpreted eruption behavior of the Sandy Bay eruption is compared to other submarine caldera-forming eruptions, notably the much smaller 2022 Hunga Tonga eruption, to assess hazards linked with such end-member eruption style.