TY - JOUR

T1 - Bubble-enhanced basanite–tephrite mixing in the early stages of the Cumbre Vieja 2021 eruption, La Palma, Canary Islands

AU - González-García, Diego

AU - Boulesteix, Thomas

AU - Klügel, Andreas

AU - Holtz, François

N1 - Funding Information: Open Access funding enabled and organized by Projekt DEAL. The present work was funded by the Alexander von Humboldt Foundation through a Humboldt Postdoctoral Fellowship to D.G.-G, by the CSIC through the CSIC-PIE project PIE20223PAL009, and by department funds of Bremen University. F.H. acknowledges support provided by DFG Research Unit 2881 (Diffusion Chronometry). Funding Information: Julian Feige is acknowledged for careful preparation of samples. The authors are grateful to PEVOLCA for granting permission for access to the exclusion zone during sampling. They would like to acknowledge Filippo Ridolfi for discussion on the interpretation of amphibole thermobarometry data, and David Neave for providing Arrhenius parameters for major element diffusion from their experimental dataset. T.B. acknowledges the CSIC deployment plan during the eruption and its coordination by Manuel Nogales.

PY - 2023

Y1 - 2023

N2 - Syneruptive magma mixing is widespread in volcanic eruptions, affecting explosivity and composition of products, but its evidence in basaltic systems is usually cryptic. Here we report direct evidence of mixing between basanitic and tephritic magmas in the first days of the 2021 Tajogaite eruption of Cumbre Vieja, La Palma. Groundmass glass in tephritic tephra from the fifth day of the eruption is locally inhomogeneous, showing micron-scale filamentary structures of Si-poor and Fe-, Mg-rich melt, forming complex filaments attached to bubbles. Their compositional distribution attests the presence of primitive basanitic magma, with compositions similar to late-erupted melts, interacting with an evolved tephritic melt during the first week of the event. From filament morphology, we suggest their generation by dragging and folding of basanitic melt during bubble migration through melt interfaces. Semi-quantitative diffusion modelling indicates that the filamentary structures are short-lived, dissipating in timescales of tens of seconds. In combination with thermobarometric constraints, we suggest a mixing onset by sub-Moho remobilization of a tephritic reservoir by basanite input, followed by turbulent ascent of a mingled magma. In the shallow conduit or lava fountain, bubble nucleation and migration triggered further mingling of the distinct melt-phases. This phenomenon might have enhanced the explosive behaviour of the eruption in such period, where violent strombolian explosions were common.

AB - Syneruptive magma mixing is widespread in volcanic eruptions, affecting explosivity and composition of products, but its evidence in basaltic systems is usually cryptic. Here we report direct evidence of mixing between basanitic and tephritic magmas in the first days of the 2021 Tajogaite eruption of Cumbre Vieja, La Palma. Groundmass glass in tephritic tephra from the fifth day of the eruption is locally inhomogeneous, showing micron-scale filamentary structures of Si-poor and Fe-, Mg-rich melt, forming complex filaments attached to bubbles. Their compositional distribution attests the presence of primitive basanitic magma, with compositions similar to late-erupted melts, interacting with an evolved tephritic melt during the first week of the event. From filament morphology, we suggest their generation by dragging and folding of basanitic melt during bubble migration through melt interfaces. Semi-quantitative diffusion modelling indicates that the filamentary structures are short-lived, dissipating in timescales of tens of seconds. In combination with thermobarometric constraints, we suggest a mixing onset by sub-Moho remobilization of a tephritic reservoir by basanite input, followed by turbulent ascent of a mingled magma. In the shallow conduit or lava fountain, bubble nucleation and migration triggered further mingling of the distinct melt-phases. This phenomenon might have enhanced the explosive behaviour of the eruption in such period, where violent strombolian explosions were common.

UR - http://www.scopus.com/inward/record.url?scp=85170204205&partnerID=8YFLogxK

U2 - 10.1038/s41598-023-41595-3

DO - 10.1038/s41598-023-41595-3

M3 - Article

C2 - 37684313

AN - SCOPUS:85170204205

VL - 13

JO - Scientific reports

JF - Scientific reports

SN - 2045-2322

IS - 1

M1 - 14839

ER -