Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating
Ljósufjöll volcano is the largest outcrop of silicic volcanic material in the volcanic Snaefellsnes flank (non-rifting) zone of Iceland. The silicic eruptives range from trachytes to alkaline and peralkaline (comenditic) rhyolites and show evidence for eruption in both subaerial and subglacial envir...
Published in: | Journal of Volcanology and Geothermal Research |
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ftopenunivgb:oai:oro.open.ac.uk:26984 2023-06-11T04:13:05+02:00 Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating Flude, Stephanie Burgess, Ray McGarvie, Dave 2008-02 https://oro.open.ac.uk/26984/ https://doi.org/10.1016/j.jvolgeores.2007.08.019 unknown Flude, Stephanie <http://oro.open.ac.uk/view/person/sf4764.html>; Burgess, Ray and McGarvie, Dave <http://oro.open.ac.uk/view/person/dwm4.html> (2008). Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating. Journal of Volcanology and Geothermal Research, 169(3-4) pp. 154–175. Journal Item None PeerReviewed 2008 ftopenunivgb https://doi.org/10.1016/j.jvolgeores.2007.08.019 2023-05-28T05:45:57Z Ljósufjöll volcano is the largest outcrop of silicic volcanic material in the volcanic Snaefellsnes flank (non-rifting) zone of Iceland. The silicic eruptives range from trachytes to alkaline and peralkaline (comenditic) rhyolites and show evidence for eruption in both subaerial and subglacial environments. Thirteen silicic eruptive units have been identified and mapped by a combination of field observations and geochemical correlation. The trachytes probably formed by fractional crystallisation of a basaltic magma to form an alkali feldspar-rich trachytic mush, with continued fractionation of the interstitial melt producing low Ba and Sr rhyolite magma. Ar–Ar dating of feldspars and matrix (glass or holocrystalline groundmass) has been carried out on twelve of the units. Many units have a complex Ar-isotopic system, with many samples showing evidence for inherited 40 Ar in the form of feldspar xenocrysts. The deduced eruption ages span an age range from < 129ka to > 650ka. The eruptive history of Ljósufjöll probably extends further back than this but the products of previous eruptions have since been removed by erosion or buried. A syenite xenolith was dated at 1.1Ma, indicating that silicic, alkaline magmatism has been occurring at Ljósufjöll for over one million years. Eruptions of silicic material at Ljósufjöll appear to be more common during times of rapid climate change and fluctuating ice volume. Article in Journal/Newspaper Iceland The Open University: Open Research Online (ORO) Journal of Volcanology and Geothermal Research 169 3-4 154 175 |
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Open Polar |
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The Open University: Open Research Online (ORO) |
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ftopenunivgb |
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unknown |
description |
Ljósufjöll volcano is the largest outcrop of silicic volcanic material in the volcanic Snaefellsnes flank (non-rifting) zone of Iceland. The silicic eruptives range from trachytes to alkaline and peralkaline (comenditic) rhyolites and show evidence for eruption in both subaerial and subglacial environments. Thirteen silicic eruptive units have been identified and mapped by a combination of field observations and geochemical correlation. The trachytes probably formed by fractional crystallisation of a basaltic magma to form an alkali feldspar-rich trachytic mush, with continued fractionation of the interstitial melt producing low Ba and Sr rhyolite magma. Ar–Ar dating of feldspars and matrix (glass or holocrystalline groundmass) has been carried out on twelve of the units. Many units have a complex Ar-isotopic system, with many samples showing evidence for inherited 40 Ar in the form of feldspar xenocrysts. The deduced eruption ages span an age range from < 129ka to > 650ka. The eruptive history of Ljósufjöll probably extends further back than this but the products of previous eruptions have since been removed by erosion or buried. A syenite xenolith was dated at 1.1Ma, indicating that silicic, alkaline magmatism has been occurring at Ljósufjöll for over one million years. Eruptions of silicic material at Ljósufjöll appear to be more common during times of rapid climate change and fluctuating ice volume. |
format |
Article in Journal/Newspaper |
author |
Flude, Stephanie Burgess, Ray McGarvie, Dave |
spellingShingle |
Flude, Stephanie Burgess, Ray McGarvie, Dave Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating |
author_facet |
Flude, Stephanie Burgess, Ray McGarvie, Dave |
author_sort |
Flude, Stephanie |
title |
Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating |
title_short |
Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating |
title_full |
Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating |
title_fullStr |
Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating |
title_full_unstemmed |
Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating |
title_sort |
silicic volcanism at ljósufjöll, iceland: insights into evolution and eruptive history from ar–ar dating |
publishDate |
2008 |
url |
https://oro.open.ac.uk/26984/ https://doi.org/10.1016/j.jvolgeores.2007.08.019 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
Flude, Stephanie <http://oro.open.ac.uk/view/person/sf4764.html>; Burgess, Ray and McGarvie, Dave <http://oro.open.ac.uk/view/person/dwm4.html> (2008). Silicic volcanism at Ljósufjöll, Iceland: insights into evolution and eruptive history from Ar–Ar dating. Journal of Volcanology and Geothermal Research, 169(3-4) pp. 154–175. |
op_doi |
https://doi.org/10.1016/j.jvolgeores.2007.08.019 |
container_title |
Journal of Volcanology and Geothermal Research |
container_volume |
169 |
container_issue |
3-4 |
container_start_page |
154 |
op_container_end_page |
175 |
_version_ |
1768389707212783616 |