Explosive Behavior of Intermediate Magmas: The Example of Cotopaxi Volcano (Ecuador)
| Autor: | Marco Pistolesi, Chiara Vigiani, Raffaello Cioni, Costanza Bonadonna, Alvaro Aravena, Licia Costantini |
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| Přispěvatelé: | Dipartimento di Scienze della Terra [Pisa], University of Pisa - Università di Pisa, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Département des Sciences de la Terre, Université de Genève, Dipartimento di Scienze della Terra [Firenze] (DST), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), Université de Genève = University of Geneva (UNIGE), Università degli Studi di Firenze = University of Florence (UniFI) |
| Rok vydání: | 2021 |
| Předmět: |
C. Vigiani Writing -review & editing: M. Pistolesi
C. Bonadonna Resources: M. Pistolesi 010504 meteorology & atmospheric sciences Explosive material Cotopaxi R. Cioni conduit dynamics C. Bonadonna Methodology: A. Aravena Volcanism C. Bonadonna Validation: M. Pistolesi engineering.material C. Bonadonna 010502 geochemistry & geophysics 01 natural sciences Texture (geology) L. Costantini Microlite Geochemistry and Petrology A. Aravena [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology ddc:550 vesicle number density Petrology M. Pistolesi 0105 earth and related environmental sciences geography geography.geographical_feature_category Explosive eruption magma rheology Geophysics Volcano 13. Climate action eruptive source parameters Magma engineering Phenocryst explosive eruptions intermediate magmas C. Vigiani C. Bonadonna Writing -original draft: M. Pistolesi C. Bonadonna Supervision: M. Pistolesi Geology |
| Zdroj: | Geochemistry, geophysics, geosystems, Vol. 22, No 11 (2021) Geochemistry, Geophysics, Geosystems Geochemistry, Geophysics, Geosystems, AGU and the Geochemical Society, 2021, 22 (11), ⟨10.1029/2021GC009991⟩ Geochemistry, Geophysics, Geosystems, 2021, 22 (11), ⟨10.1029/2021GC009991⟩ |
| ISSN: | 1525-2027 |
| DOI: | 10.1029/2021gc009991 |
| Popis: | Co-auteur étranger; International audience; The variability in intensity and style shown by explosive volcanism has been traditionally explained by a complex interplay among melt composition and pre-eruptive volatile content, which modulate magma ascent and conduit dynamics. However, magmas having similar compositions may becharacterized by subtle textural changes affecting magma rheology and eventually explosive dynamics. Here we study five eruptions occurred at Cotopaxi volcano (Ecuador) in the last 2000 years characterized by a small variation in magma composition but spanning a wide range of intensity to investigate how these parameters control variations in eruption dynamics. We combined eruption source parameters (ESPs), obtained from the application of recent models to all the available field data, with new textural data and state-of-the-art conduit dynamics modeling. We found that, despite having variable microlite content and texture, the effect of microlite on magma rheology is partly counterbalanced by variablephenocryst abundance, resulting in a comparable total crystal content. The combination of modeling results with textural data and ESPs suggests that subtle variability in crystal content and magma composition may be accompanied by strong feedback effects among crystallization, changes in melt/ magma viscosity and volatile exsolution, with microlite crystallization resulting in a rapid change of magma rheology and modifications in the explosive dynamics. By combining ESPs with quantitative textural data (i.e. melt normalized vesicle number density) and conduit modeling, we also show how general observed correlations between composition and texture of juvenile products with eruption intensity are not evident when applied to eruptions characterized by a small compositional range. |
| Databáze: | OpenAIRE |
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