title: Role of syn-eruptive plagioclase disequilibrium crystallization in basaltic magma ascent dynamics.
abstract: Timescales of magma ascent in conduit models are typically assumed to be much longer than crystallization and gas exsolution for basaltic eruptions. However, it is now recognized that basaltic magmas may rise fast enough for disequilibrium processes to play a key role on the ascent dynamics. The quantification of the characteristic times for crystallization and exsolution processes are fundamental to our understanding of such disequilibria and ascent dynamics. Here we use observations from Mount Etna's 2001 eruption and a magma ascent model to constrain timescales for crystallization and exsolution processes. Our results show that plagioclase reaches equilibrium in 1-2 h, whereas ascent times were <1 h. Using these new constraints on disequilibrium plagioclase crystallization we also reproduce observed crystal abundances for different basaltic eruptions. The strong relation between magma ascent rate and disequilibrium crystallization and exsolution plays a key role in controlling eruption dynamics in basaltic volcanism.
authors.affiliation: School of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
authors.forename: G
authors.initials: G
authors.lastname: La Spina
authors.affiliation: School of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
authors.forename: M
authors.identifier: 0000-0003-3779-4812
authors.initials: M
authors.lastname: Burton
authors.affiliation: Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Pisa 56126, Italy.
authors.forename: M
authors.initials: M
authors.lastname: De' Michieli Vitturi
authors.affiliation: School of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
authors.forename: F
authors.initials: F
authors.lastname: Arzilli