The University of Southampton
University of Southampton Institutional Repository

Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat

Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat
Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat
Volcanism on Montserrat (Lesser Antilles arc) has migrated southwards since the formation of the Silver Hills ~ 2.5 Ma, and has formed three successively active volcanic centres. The Centre Hills volcano was the focus of volcanism from ~ 1–0.4 Ma, before activity commenced at the currently active Soufrière Hills volcano. The history of activity at these two volcanoes provides an opportunity to investigate the pattern of volcano behaviour on an andesitic arc island over the lifetime of individual volcanoes. Here, we describe the pyroclastic stratigraphy of subaerial exposures around central Montserrat; identifying 11 thick (> 1 m) pumiceous units derived from sustained explosive eruptions of Centre Hills from ~ 0.8–0.4 Ma. Over 10 other, less well- exposed pumiceous units have also been identified. The pumice-rich units are interbedded with andesite lava breccias derived from effusive, dome-forming eruptions of Centre Hills. The stratigraphy indicates that large (up to magnitude 5) explosive eruptions occurred throughout the history of Centre Hills, alongside effusive activity. This behaviour at Centre Hills contrasts with Soufrière Hills, where deposits from sustained explosive eruptions are much less common and restricted to early stages of activity at the volcano, from ~ 175–130 ka. Subsequent eruptions at Soufriere Hills have been dominated by andesitic effusive eruptions. The bulk composition, petrography and mineral chemistry of volcanic rocks from Centre Hills and Soufrière Hills are similar throughout the history of both volcanoes, except for occasional, transient departures to different magma compositions, which mark shifts in vent location or dominant eruption style. For example, the final recorded eruption of Centre Hills, before the initiation of activity at Soufrière Hills, was more silicic than any other identified eruption on Montserrat; and the basaltic South Soufrière Hills episode marked the transition to the current stage of predominantly effusive Soufrière Hills activity. The compositional stability observed throughout the history of Centre Hills and Soufrière Hills suggests that a predominance towards effusive or explosive eruption styles is not driven by major compositional shifts of magma, but may reflect local changes in long-term magma storage conditions that characterise individual episodes (on 105 year timescales) of volcanism on Montserrat.
0377-0273
15-35
Coussens, Maya
761d9bfc-bb42-4362-b5cd-91cbc85b53a5
Cassidy, Michael
fc0e9729-9c71-477d-a4e3-39698155e6fc
Watt, Sebastian F.L.
8cde9189-35d1-450c-bff8-f7c9107eb635
Jutzeler, Martin
3ff7423b-ed16-439c-ad5b-1822b72d7b8c
Talling, Peter J.
1cbac5ec-a9f8-4868-94fe-6203f30b47cf
Barford, Dan
970b8536-2887-4a20-acc0-8f39e4a1f8cc
Gernon, Thomas
658041a0-fdd1-4516-85f4-98895a39235e
Taylor, Rex
094be7fd-ef61-4acd-a795-7daba2bc6183
Hatter, Stuart J.
b43a8c1b-8ae3-4764-8238-3dc597aa0d71
Palmer, Martin R.
d2e60e81-5d6e-4ddb-a243-602537286080
Coussens, Maya
761d9bfc-bb42-4362-b5cd-91cbc85b53a5
Cassidy, Michael
fc0e9729-9c71-477d-a4e3-39698155e6fc
Watt, Sebastian F.L.
8cde9189-35d1-450c-bff8-f7c9107eb635
Jutzeler, Martin
3ff7423b-ed16-439c-ad5b-1822b72d7b8c
Talling, Peter J.
1cbac5ec-a9f8-4868-94fe-6203f30b47cf
Barford, Dan
970b8536-2887-4a20-acc0-8f39e4a1f8cc
Gernon, Thomas
658041a0-fdd1-4516-85f4-98895a39235e
Taylor, Rex
094be7fd-ef61-4acd-a795-7daba2bc6183
Hatter, Stuart J.
b43a8c1b-8ae3-4764-8238-3dc597aa0d71
Palmer, Martin R.
d2e60e81-5d6e-4ddb-a243-602537286080

Coussens, Maya, Cassidy, Michael, Watt, Sebastian F.L., Jutzeler, Martin, Talling, Peter J., Barford, Dan, Gernon, Thomas, Taylor, Rex, Hatter, Stuart J. and Palmer, Martin R. (2017) Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat. Journal of Volcanology and Geothermal Research, 333-334, 15-35. (doi:10.1016/j.jvolgeores.2017.01.003).

Record type: Article

Abstract

Volcanism on Montserrat (Lesser Antilles arc) has migrated southwards since the formation of the Silver Hills ~ 2.5 Ma, and has formed three successively active volcanic centres. The Centre Hills volcano was the focus of volcanism from ~ 1–0.4 Ma, before activity commenced at the currently active Soufrière Hills volcano. The history of activity at these two volcanoes provides an opportunity to investigate the pattern of volcano behaviour on an andesitic arc island over the lifetime of individual volcanoes. Here, we describe the pyroclastic stratigraphy of subaerial exposures around central Montserrat; identifying 11 thick (> 1 m) pumiceous units derived from sustained explosive eruptions of Centre Hills from ~ 0.8–0.4 Ma. Over 10 other, less well- exposed pumiceous units have also been identified. The pumice-rich units are interbedded with andesite lava breccias derived from effusive, dome-forming eruptions of Centre Hills. The stratigraphy indicates that large (up to magnitude 5) explosive eruptions occurred throughout the history of Centre Hills, alongside effusive activity. This behaviour at Centre Hills contrasts with Soufrière Hills, where deposits from sustained explosive eruptions are much less common and restricted to early stages of activity at the volcano, from ~ 175–130 ka. Subsequent eruptions at Soufriere Hills have been dominated by andesitic effusive eruptions. The bulk composition, petrography and mineral chemistry of volcanic rocks from Centre Hills and Soufrière Hills are similar throughout the history of both volcanoes, except for occasional, transient departures to different magma compositions, which mark shifts in vent location or dominant eruption style. For example, the final recorded eruption of Centre Hills, before the initiation of activity at Soufrière Hills, was more silicic than any other identified eruption on Montserrat; and the basaltic South Soufrière Hills episode marked the transition to the current stage of predominantly effusive Soufrière Hills activity. The compositional stability observed throughout the history of Centre Hills and Soufrière Hills suggests that a predominance towards effusive or explosive eruption styles is not driven by major compositional shifts of magma, but may reflect local changes in long-term magma storage conditions that characterise individual episodes (on 105 year timescales) of volcanism on Montserrat.

Text
1-s2.0-S0377027317300124-main - Accepted Manuscript
Download (6MB)
Text
Cousens et al 2017
Restricted to Repository staff only
Request a copy

More information

Accepted/In Press date: 2 January 2017
e-pub ahead of print date: 5 January 2017
Published date: 15 March 2017
Organisations: Geochemistry, Geology & Geophysics, Ocean and Earth Science, Marine Geoscience, National Oceanography Centre

Identifiers

Local EPrints ID: 406602
URI: http://eprints.soton.ac.uk/id/eprint/406602
ISSN: 0377-0273
PURE UUID: 8776bc13-27c2-4d3f-9105-8ae92b973db2
ORCID for Thomas Gernon: ORCID iD orcid.org/0000-0002-7717-2092
ORCID for Rex Taylor: ORCID iD orcid.org/0000-0002-9367-0294
ORCID for Stuart J. Hatter: ORCID iD orcid.org/0000-0003-0760-5275

Catalogue record

Date deposited: 18 Mar 2017 02:23
Last modified: 16 Mar 2024 05:07

Export record

Altmetrics

Contributors

Author: Maya Coussens
Author: Michael Cassidy
Author: Sebastian F.L. Watt
Author: Martin Jutzeler
Author: Peter J. Talling
Author: Dan Barford
Author: Thomas Gernon ORCID iD
Author: Rex Taylor ORCID iD
Author: Stuart J. Hatter ORCID iD

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×