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Weber, Gregor, Blundy, Jon, Barclay, Jenni 
ORCID: https://orcid.org/0000-0002-6122-197X, Pyle, David M., Cole, Paul, Frey, Holli, Manon, Matthew, Davies, Bridie V. ORCID: https://orcid.org/0000-0001-5771-2488 and Cashman, Katharine
(2024)
Petrology of the 2020-21 effusive to explosive eruption of La Soufrière volcano, St Vincent:Insights into plumbing system architecture and magma assembly mechanism.
In:
The 2020-21 Eruption of La Soufrière Volcano, St Vincent.
Geological Society Special Publications, 539
.
Geological Society of London, pp. 171-200.
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Abstract
The 2020–21 eruption of La Soufrière, St Vincent began with extrusion of a viscous lava dome, which was destroyed upon transition to a major explosive phase. Here we present petrological data to reconstruct the processes leading up to these events. Bulkrock SiO 2 contents range from 52.8 to 55.4 wt%, classifying the lava and the subsequent scoria as basaltic andesite, the latter being slightly more mafic. Macrocrystal chemistry and modes (plag–cpx–opx–tmt–ol) and crystallinity (45–50 vol%) are largely identical for both phases of the eruption. Pyroxenes are homogenous and precipitated mostly from andesitic melts. Conversely, plagioclase shows strong normal zonation resulting from magma ascent and stalling at multiple crustal levels. Clinopyroxene thermobarometry reveals that crystallization predominantly took place between 8 and 13 km depth at temperatures of 997 +18 −35 ◦ C. A lack of evidence for mafic recharge and changes in volatile content and the omnipresence of xenoliths, suggests pre-eruptive destabilization of an andesitic–dacitic melt pocket that disrupted and entrained antecedent mush. Olivine diffusion profiles show that this interaction preceded the onset of eruption. Low dissolved sulfur contents (≤270 ppm S) place constraints on the total SO 2 gas release. Meltmush disruption appears to be a dominant driver of eruptions at La Soufrière.
| Item Type: | Book Section |
|---|---|
| Additional Information: | Funding Information: This study was supported by the UK Natural Environment Research Council (NERC) through an Urgency Grant (NE/W000725/1) to DMP. GW acknowledges funding through an Early Postdoc. Mobility Fellowship from the Swiss National Science Foundation (SNSF). JB acknowledges funding from a Royal Society Research Professorship (RP\R1\201048). |
| Faculty \ School: | Faculty of Science > School of Environmental Sciences |
| UEA Research Groups: | Faculty of Science > Research Groups > Geosciences |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 10 May 2023 14:30 |
| Last Modified: | 30 Jan 2024 04:02 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/92013 |
| DOI: | 10.1144/SP539-2022-177 |
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