Processes Triggering Explosive Eruption of Mantle Plume-Derived Magma

Syn-eruptive monitoring of solid, fluid, and aerosol volcanic phases is one of the main approaches to survey and predict the explosivity and duration of an eruptive event. To constrain the fluid source and the temporal syn-eruptive evolution of fluid-magma system of the 2010 Eyjafjallajökull volcano...

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Bibliographic Details
Main Authors: Borisova, A. Y., Portnyagin, Maxim, Toutain, J.-P., Stefansson, A., Gouy, S., de Parseval, P.
Format: Conference Object
Language:unknown
Published: 2011
Subjects:
Katla
Eyjafjallajökull
Hekla
Iceland
Online Access:https://oceanrep.geomar.de/id/eprint/13398/
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Summary:Syn-eruptive monitoring of solid, fluid, and aerosol volcanic phases is one of the main approaches to survey and predict the explosivity and duration of an eruptive event. To constrain the fluid source and the temporal syn-eruptive evolution of fluid-magma system of the 2010 Eyjafjallajökull volcano (South Iceland), we investigated the chemistry of lapilli, ash, and leachates, as well as ash-of plume-derived aerosols (silicate glass and Cl-S-K-Na-Ca salt particles) sampled over Europe. The mechanisms that triggered or impeded explosive eruption were likely controlled by syn-eruptive mixing of dry, S-rich, Fe-Ti basaltic magma with differentiated hydrous Cl-rich 1821-1823 trachydacitic magma producing more than ~40 kt of the mixed magma. Our data suggest that high explosivity phreatoplinian eruption resulted from bulk production of 160 to 2600 kt of Cl-S-rich aqueous fluid liberated principally from the differentiated hydrous trachydacitic magma. This magma was enriched in volatiles (e.g., B, Cl, As), mobile LILE (e.g., K, Rb, Sr, Cs) and immobile HFSE (e.g., Nb, Zr, Th, U) elements. Sr-Nd-Pb isotopic data on the 2010 Eyjafjallajökull lapilli and ash products demonstrate that this enriched component was derived from oceanic lithosphere entrained in a deep mantle plume rather than from shallow hydrothermally altered oceanic crust. Such a volatile-rich mantle plume source explains the high explosivity of strongly differentiated felsic Icelandic magmas especially those of the Southeast group (Eyjafjallajökull, Katla and Hekla).

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