A model of degassing for Stromboli volcano | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

Twitter

Aller au compte twitter

  A model of degassing for Stromboli volcano

Type de publication:

Journal Article

Source:

Earth and Planetary Science Letters, Volume 295, Ticket 1-2, p.195-204 (2010)

ISBN:

0012-821X

Numéro d'accès:

ISI:000278974300020

URL:

Cited by in Scopus (11)

Mots-clés:

UMR 7154 ; Géologie des systèmes volcaniques ; volcanic degassing; Stromboli; volcanic gases; CO2 fluxing

Résumé:

A better understanding of degassing processes at open-vent basaltic volcanoes requires collection of new datasets of H2O-CO2-SO2 volcanic gas plume compositions, which acquisition has long been hampered by technical limitations. Here, we use the MultiGAS technique to provide the best-documented record of gas plume discharges from Stromboli volcano to date. We show that Stromboli's gases are dominated by H2O (48-98 mol%; mean, 80%), and by CO2 (2-50 mol%; mean, 17%) and SO2 (0.2-14 mol%; mean, 3%). The significant temporal variability in our dataset reflects the dynamic nature of degassing process during Strombolian activity; which we explore by interpreting our gas measurements in tandem with the melt inclusion record of pre-eruptive dissolved volatile abundances, and with the results of an equilibrium saturation model. Comparison between natural (volcanic gas and melt inclusion) and modelled compositions is used to propose a degassing mechanism for Stromboli volcano, which suggests surface gas discharges are mixtures of CO2-rich gas bubbles supplied from the deep (>4 km) plumbing system, and gases released from degassing of dissolved volatiles in the magma filling the upper conduits. The proposed mixing mechanism offers a viable and general model to account for composition of gas discharges at all volcanoes for which petrologic evidence of CO2 fluxing exists. A combined volcanic gas-melt inclusion-modelling approach, as used in this paper, provides key constraints on degassing processes, and should thus be pursued further. (C) 2010 Elsevier B.V. All rights reserved.

Notes:

Aiuppa, A. Bertagnini, A. Metrich, N. Moretti, R. Di Muro, A. Liuzzo, M. Tamburello, G.