Magma residence time, ascent rate and eruptive style of the November ash-laden activity during the 2021 Tajogaite eruption (La Palma, Spain)

Autor: Barbara Bonechi, Margherita Polacci, Fabio Arzilli, Jorge Romero, Jonathan Fellowes, Mike Burton
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Volcanica, Vol 7, Iss 1, Pp 51-65 (2024)
Druh dokumentu: article
ISSN: 2610-3540
DOI: 10.30909/vol.07.01.5165
Popis: We combined compositional analyses, crystal size distributions and geothermobarometry of tephra erupted during the 2021 Tajogaite eruption (La Palma, Spain), focusing on samples collected in November 2021 associated with a period of abundant ash emission characteristic of the second half of the eruption (from October onwards). Magma erupted in November exhibits a more primitive basanitic composition than the earlier magma. Crystallisation temperatures range between ~1100–1160 °C (H2O = 1–3 wt.%) for phenocrysts and microphenocrysts, with corresponding pressures indicating depths from ~10 to ~30 km. Crystal size distribution analysis reveals short (minutes) residence times for plagioclase. Finally, magma ascent velocities (~0.01–0.3 m s−1) suggest acceleration and fragmentation in the shallowest part of the conduit. Our results suggest that the trigger of the November explosive activity can be attributed to complex feedback between gas emission rates, changes in conduit geometry, and magma ascent rate.
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