Petrologic evidence for pressure-temperature conditions and recent reheating of andesitic magma erupting at Soufriere Hills Volcano, Montserrat, WI

Devine, J. D., Murphy, M. D., Rutherford, M., Barclay, J. ORCID: https://orcid.org/0000-0002-6122-197X, Sparks, R. S. J., Carroll, M. R., Young, S. R. and Gardner, J. E. (1998) Petrologic evidence for pressure-temperature conditions and recent reheating of andesitic magma erupting at Soufriere Hills Volcano, Montserrat, WI. Geophysical Research Letters, 25 (19). pp. 3669-3672. ISSN 1944-8007

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Abstract

The recent eruption of the Soufriere Hills Volcano in Montserrat (July, 1995, to present; September, 1997) has produced an andesitic dome (SiO2 ∼ 59–61 wt.%). The eruption has been caused by invasion of mafic magma into a preexisting andesitic magma storage region (P ∼ 130 MPa; ≥5 km depth). The composition of the andesite has remained essentially constant throughout the eruption, but heating by the mafic magma increased the andesite temperature from ≤830°C to ≤880°C. Prior to being heated, the stable mineral assemblage in the andesite was plagioclase + amphibole + orthopyroxene + titanomagnetite + ilmenite + quartz. The rise in temperature from ≤830°C to ≤880°C (fO2 ∼ 1 log unit above NNO) has caused quartz to become unstable, and has also caused changes in silicate and Fe-Ti oxide mineral compositions. The andesitic magma is likely saturated with an H2O-rich vapor phase in the upper part of the magma storage region. Melt H2O content is ∼4.7 wt.%.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Environmental Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Geosciences Faculty of Science > Research Groups > Volcanoes@UEA (former - to 2018) Faculty of Science > Research Groups > Geosciences and Natural Hazards (former - to 2017)
Depositing User:	Rachel Snow
Date Deposited:	28 Mar 2011 10:51
Last Modified:	24 Jul 2024 08:42
URI:	https://ueaeprints.uea.ac.uk/id/eprint/27301
DOI:	10.1029/98GL01330

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