ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Petrology
Paleo-Phreatomagmatic Eruption on Daru Island, Papua New Guinea: Evidence for Carbonate-Basalt Magma Mingling and Peperite Formation
Provisionally accepted
- Akita University, Akita, Japan
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This study presents evidence for a maar-type paleo-phreatomagmatic eruption on Daru Island, Papua New Guinea (PNG), an understudied region of the southwest Pacific. Integrated field observations, petrographic and back-scattered electron (BSE) ash mapping, mineral chemistry, and whole-rock geochemistry reveal that ash generation was controlled by repeated interaction between ascending basaltic magma and seawater-saturated carbonate sediments at shallow crustal levels. Ash textures, morphologies, vesicularity, and juvenile-lithic proportions record spatial changes in quenching efficiency, degassing behavior, and sediment entrainment during magma emplacement. Three end-member interaction zones were classified based on ash-mapping: (1) a marginal quench zone (Dark to Black Ash-type), (2) an intermediate interaction zone (Brown Ash-type), and (3) an interior insulated magma zone (Mixed Ash-type). These variations record repeated fragmentation and recycling of ash populations, producing maar-type volcaniclastic tuffs and providing new insights into basaltic volcanism processes in carbonate-dominated sedimentary basins such as the Fly Platform in PNG.
Keywords: carbonate-basalt magma mingling, Daru Island, Fly Platform, Papua New Guinea, Peperite, Phreatomagmatic eruptions
Received: 17 Oct 2025; Accepted: 26 Jan 2026.
Copyright: © 2026 Lunge, Ohba and Hoshide. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Moira Lunge
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