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Magma dehydration controls the energy of recent eruptions at Mt. Etna volcano
Author(s) -
Zuccarello Francesco,
Schiavi Federica,
Viccaro Marco
Publication year - 2021
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12527
Subject(s) - tephra , olivine , geology , magma , volcano , melt inclusions , geochemistry , magmatic water , magma chamber , earth science , petrology , seismology , meteoric water , hydrothermal circulation
Olivine‐hosted melt inclusions (MIs) from tephra of the recent 2013–2018 activity at Mt. Etna were investigated for assessing the chemical evolution of magmas and quantifying their pre‐eruptive volatile budget. Microanalyses revealed two types of MIs present in all investigated eruptions; the inclusions, particularly the less evolved ones, appear to have experienced water loss coupled with SiO 2 depletion. Restoration of the original SiO 2 ‐H 2 O concentrations provides consistency with the thermodynamic modelling of magma evolution. The two types of MIs developed during crystallization of olivine plus clinopyroxene between 200 and 100 MPa, where magmas also experienced CO 2 flushing. Degassing processes at these levels are responsible for water depletion in the melt and diffusive water loss from inclusions. Our data suggest that initial water budget is unchanged all over the last 20 years, reflecting therefore a potential in triggering highly explosive eruptions depending on degassing dynamics under open versus closed system conditions at shallow levels.