Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland
Water content plays a significant role in magma genesis, ascent rate, and, ultimately, in the style and intensity of volcanic eruptions, due to its control on the density, viscosity and melting behaviour of silicate melts. A reliable method for determining the pre-eruptive magmatic water content is...
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2023
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ftunivfreiburg:oai:freidok.uni-freiburg.de:240704 2024-02-11T10:05:04+01:00 Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland Radu, Ioana-Bogdana Skogby, Henrik Troll, Valentin R. Deegan, Frances M. Geiger, Harri Müller, Daniel Thordarson, Thor 2023 pdf https://freidok.uni-freiburg.de/data/240704 https://nbn-resolving.org/urn:nbn:de:bsz:25-freidok-2407042 https://doi.org/10.1007/s00445-023-01641-4 https://freidok.uni-freiburg.de/dnb/download/240704 eng eng https://freidok.uni-freiburg.de/data/240704 free ISSN: 1432-0819 article 2023 ftunivfreiburg https://doi.org/10.1007/s00445-023-01641-4 2024-01-14T23:52:57Z Water content plays a significant role in magma genesis, ascent rate, and, ultimately, in the style and intensity of volcanic eruptions, due to its control on the density, viscosity and melting behaviour of silicate melts. A reliable method for determining the pre-eruptive magmatic water content is to use phenocrysts of nominally anhydrous minerals (NAMs) which can preserve water as hydrogen configurations in structural defects. The advantage of this method is that eruptive changes such as water loss during magma degassing may be experimentally reconstructed and analysed by infrared spectroscopy. Applying this to clinopyroxene crystals (n=17) from lava samples (n=7) from April 2021 of the Geldingadalir eruption, SW-Iceland, reveals parental water contents of 0.69 ± 0.07 to 0.86 ± 0.09 wt. % H2O. These values are higher than those expected for typical mid-ocean ridge basalts (MORB 0.3–0.5 wt. % on average) indicating a significant plume (OIB) contribution to the magma source. Moreover, such water concentrations would imply that water saturation in the ascending Geldingadalir magmas was attained only at very shallow levels within the plumbing system. This could explain the at times pulsating behaviour within the uppermost conduit system as being the result of shallow episodic water vapour exsolution in addition to the deep-sourced CO2 flux. Article in Journal/Newspaper Iceland University of Freiburg: FreiDok Bulletin of Volcanology 85 5 |
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University of Freiburg: FreiDok |
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ftunivfreiburg |
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English |
description |
Water content plays a significant role in magma genesis, ascent rate, and, ultimately, in the style and intensity of volcanic eruptions, due to its control on the density, viscosity and melting behaviour of silicate melts. A reliable method for determining the pre-eruptive magmatic water content is to use phenocrysts of nominally anhydrous minerals (NAMs) which can preserve water as hydrogen configurations in structural defects. The advantage of this method is that eruptive changes such as water loss during magma degassing may be experimentally reconstructed and analysed by infrared spectroscopy. Applying this to clinopyroxene crystals (n=17) from lava samples (n=7) from April 2021 of the Geldingadalir eruption, SW-Iceland, reveals parental water contents of 0.69 ± 0.07 to 0.86 ± 0.09 wt. % H2O. These values are higher than those expected for typical mid-ocean ridge basalts (MORB 0.3–0.5 wt. % on average) indicating a significant plume (OIB) contribution to the magma source. Moreover, such water concentrations would imply that water saturation in the ascending Geldingadalir magmas was attained only at very shallow levels within the plumbing system. This could explain the at times pulsating behaviour within the uppermost conduit system as being the result of shallow episodic water vapour exsolution in addition to the deep-sourced CO2 flux. |
format |
Article in Journal/Newspaper |
author |
Radu, Ioana-Bogdana Skogby, Henrik Troll, Valentin R. Deegan, Frances M. Geiger, Harri Müller, Daniel Thordarson, Thor |
spellingShingle |
Radu, Ioana-Bogdana Skogby, Henrik Troll, Valentin R. Deegan, Frances M. Geiger, Harri Müller, Daniel Thordarson, Thor Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland |
author_facet |
Radu, Ioana-Bogdana Skogby, Henrik Troll, Valentin R. Deegan, Frances M. Geiger, Harri Müller, Daniel Thordarson, Thor |
author_sort |
Radu, Ioana-Bogdana |
title |
Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland |
title_short |
Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland |
title_full |
Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland |
title_fullStr |
Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland |
title_full_unstemmed |
Water in clinopyroxene from the 2021 Geldingadalir eruption of the Fagradalsfjall Fires, SW-Iceland |
title_sort |
water in clinopyroxene from the 2021 geldingadalir eruption of the fagradalsfjall fires, sw-iceland |
publishDate |
2023 |
url |
https://freidok.uni-freiburg.de/data/240704 https://nbn-resolving.org/urn:nbn:de:bsz:25-freidok-2407042 https://doi.org/10.1007/s00445-023-01641-4 https://freidok.uni-freiburg.de/dnb/download/240704 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
ISSN: 1432-0819 |
op_relation |
https://freidok.uni-freiburg.de/data/240704 |
op_rights |
free |
op_doi |
https://doi.org/10.1007/s00445-023-01641-4 |
container_title |
Bulletin of Volcanology |
container_volume |
85 |
container_issue |
5 |
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1790601909700132864 |