An explosive–intrusive subglacial rhyolite eruption at Dalakvísl, Torfajökull, Iceland
- Tuffen, H.
- McGarvie, D. W.
- Pinkerton, H.
- Gilbert, J. S.
- Brooker, R. A.
DOIAbstract
This paper describes unusual rhyolitic deposits at Dalakvísl, Torfajökull, Iceland that were emplaced during a Quaternary subglacial eruption. Despite its small volume (<0.2 km3), the eruption mechanisms were highly variable and involved both explosive and intrusive phases. The explosive phase involved vesiculation-driven magma fragmentation at the glacier base and generated a pumiceous pyroclastic deposit containing deformed sheets of dense obsidian. Textures suggest that the obsidian was generated by the collapse of partly fragmented foam that was intruding the deposit and water contents indicate quenching at elevated pressures. In contrast, the intrusive phase of the eruption generated vesicle-poor quench hyaloclastites associated with a...
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