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Reactive halogens (BrO and OClO) detected in the plume of Soufrière Hills Volcano during an eruption hiatus


Type

Article

Change log

Authors

Tsanev, V 

Abstract

jats:titleAbstract</jats:title>jats:pVolcanic plumes are sites of dynamic chemistry involving halogen gases. Here we present new data on the relative abundances of SOjats:sub2</jats:sub>, BrO and OClO gases emitted from Soufrière Hills Volcano [SHV). They were collected during an eruptive hiatus but during sustained degassing at this halogen‐rich volcano. By comparison with data from a previous study during an eruptive phase and application of the data and modeling of Villemant et al. (2008), we suggest that, after consideration of errors, either the rate of HBr conversion to BrO is variable, ranging from ∼30% to ∼15%, and/or the relative partitioning of Cl and Br into the gas phase from the melt changes according to eruptive activity. We examine the potential implications of this for fluid‐melt partitioning, and compare our results with data from the experimental literature. Our work contributes toward understanding the controls on the BrO/SOjats:sub2</jats:sub> ratio for volcano monitoring purposes; the changes in plume chemistry with regard to bromine at the onset of lava extrusion may be large and rapid. OClO was detected in the plume at SHV for the first time. This species has only previously been detected in emissions from Mount Etna (using ground‐based methods) and from Puyehue Cordon Caulle (using satellite‐based methods). No HCHO or NOjats:suby</jats:sub> species were detected in the spectra.</jats:p>

Description

Keywords

halogens in volcanic systems, volcanic degassing, DOAS

Journal Title

Geochemistry, Geophysics, Geosystems

Conference Name

Journal ISSN

1525-2027
1525-2027

Volume Title

15

Publisher

American Geophysical Union (AGU)
Sponsorship
NERC (via University of Leeds) (GA/13M/031)
The MVO is thanked for support during fieldwork. This work was also supported by the UK National Centre for Earth Observation (“Dynamic Earth and Geohazards"; http://comet.nerc.ac.uk).