Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes
Lithological variations in the mantle source regions under mid-ocean ridges and ocean islands have been proposed to play a key role in controlling melt generation and basalt composition. Here we combine compositional observations from Icelandic basalts and modelling of melting of a bi-lithologic per...
Published in: | Geochemistry, Geophysics, Geosystems |
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Online Access: | http://eprints.esc.cam.ac.uk/2228/ http://eprints.esc.cam.ac.uk/2228/1/2011GC003748-pip.pdf http://eprints.esc.cam.ac.uk/2228/7/ggge2058.pdf http://eprints.esc.cam.ac.uk/2228/9/ggge2058-sup-0001-readme.txt http://eprints.esc.cam.ac.uk/2228/8/ggge2058-sup-0002-ds01.csv http://eprints.esc.cam.ac.uk/2228/10/ggge2058-fig-0001.png https://doi.org/10.1029/2011GC003748 |
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ftucambridgeesc:oai:eprints.esc.cam.ac.uk:2228 2023-05-15T16:48:32+02:00 Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes Shorttle, Oliver Maclennan, John 2011-11 text image http://eprints.esc.cam.ac.uk/2228/ http://eprints.esc.cam.ac.uk/2228/1/2011GC003748-pip.pdf http://eprints.esc.cam.ac.uk/2228/7/ggge2058.pdf http://eprints.esc.cam.ac.uk/2228/9/ggge2058-sup-0001-readme.txt http://eprints.esc.cam.ac.uk/2228/8/ggge2058-sup-0002-ds01.csv http://eprints.esc.cam.ac.uk/2228/10/ggge2058-fig-0001.png https://doi.org/10.1029/2011GC003748 en eng AGU http://eprints.esc.cam.ac.uk/2228/1/2011GC003748-pip.pdf http://eprints.esc.cam.ac.uk/2228/7/ggge2058.pdf http://eprints.esc.cam.ac.uk/2228/9/ggge2058-sup-0001-readme.txt http://eprints.esc.cam.ac.uk/2228/8/ggge2058-sup-0002-ds01.csv http://eprints.esc.cam.ac.uk/2228/10/ggge2058-fig-0001.png Shorttle, Oliver and Maclennan, John (2011) Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes. Geochemistry Geophysics Geosystems, 12. Q11008. ISSN 1525-2027 DOI https://doi.org/10.1029/2011GC003748 <https://doi.org/10.1029/2011GC003748> cc_by CC-BY 02 - Geodynamics Geophysics and Tectonics Article PeerReviewed 2011 ftucambridgeesc https://doi.org/10.1029/2011GC003748 2020-08-27T18:09:11Z Lithological variations in the mantle source regions under mid-ocean ridges and ocean islands have been proposed to play a key role in controlling melt generation and basalt composition. Here we combine compositional observations from Icelandic basalts and modelling of melting of a bi-lithologic peridotite-pyroxenite mantle to demonstrate that, while short-lengthscale major element variation is present in the mantle under Iceland, source heterogeneity does not make an important contribution to excess melt production. By identifying the major element characteristics of endmember Icelandic melts, we find enriched melts to be characterised by low SiO2 and CaO, but high FeO. We quantitatively compare endmember compositions to experimental partial melts generated from a range of lithologies, pressures and melt fractions. This comparison indicates that a single source composition cannot account for all the major element variation; depleted Icelandic melts can be produced by depleted peridotite melting, but the major element composition of enriched melts is best matched by melting of mantle sources that have been refertilised by the addition of up to 40% mid-ocean ridge basalt. The enriched source beneath Iceland is more fusible than the source of depleted melts, and as such will be over-represented in accumulated melts compared with its abundance in the source. Modelling of peridotite-pyroxenite melting, combined with our observational constraints on the composition of the Icelandic mantle, indicates that crustal thickness variations in the North Atlantic must be primarily due to mantle temperature and flow field variations. Article in Journal/Newspaper Iceland North Atlantic University of Cambridge, Department of Earth Sciences: ESC Publications Geochemistry, Geophysics, Geosystems 12 11 n/a n/a |
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Open Polar |
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University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
02 - Geodynamics Geophysics and Tectonics |
spellingShingle |
02 - Geodynamics Geophysics and Tectonics Shorttle, Oliver Maclennan, John Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes |
topic_facet |
02 - Geodynamics Geophysics and Tectonics |
description |
Lithological variations in the mantle source regions under mid-ocean ridges and ocean islands have been proposed to play a key role in controlling melt generation and basalt composition. Here we combine compositional observations from Icelandic basalts and modelling of melting of a bi-lithologic peridotite-pyroxenite mantle to demonstrate that, while short-lengthscale major element variation is present in the mantle under Iceland, source heterogeneity does not make an important contribution to excess melt production. By identifying the major element characteristics of endmember Icelandic melts, we find enriched melts to be characterised by low SiO2 and CaO, but high FeO. We quantitatively compare endmember compositions to experimental partial melts generated from a range of lithologies, pressures and melt fractions. This comparison indicates that a single source composition cannot account for all the major element variation; depleted Icelandic melts can be produced by depleted peridotite melting, but the major element composition of enriched melts is best matched by melting of mantle sources that have been refertilised by the addition of up to 40% mid-ocean ridge basalt. The enriched source beneath Iceland is more fusible than the source of depleted melts, and as such will be over-represented in accumulated melts compared with its abundance in the source. Modelling of peridotite-pyroxenite melting, combined with our observational constraints on the composition of the Icelandic mantle, indicates that crustal thickness variations in the North Atlantic must be primarily due to mantle temperature and flow field variations. |
format |
Article in Journal/Newspaper |
author |
Shorttle, Oliver Maclennan, John |
author_facet |
Shorttle, Oliver Maclennan, John |
author_sort |
Shorttle, Oliver |
title |
Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes |
title_short |
Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes |
title_full |
Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes |
title_fullStr |
Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes |
title_full_unstemmed |
Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes |
title_sort |
compositional trends of icelandic basalts: implications for short–length scale lithological heterogeneity in mantle plumes |
publisher |
AGU |
publishDate |
2011 |
url |
http://eprints.esc.cam.ac.uk/2228/ http://eprints.esc.cam.ac.uk/2228/1/2011GC003748-pip.pdf http://eprints.esc.cam.ac.uk/2228/7/ggge2058.pdf http://eprints.esc.cam.ac.uk/2228/9/ggge2058-sup-0001-readme.txt http://eprints.esc.cam.ac.uk/2228/8/ggge2058-sup-0002-ds01.csv http://eprints.esc.cam.ac.uk/2228/10/ggge2058-fig-0001.png https://doi.org/10.1029/2011GC003748 |
genre |
Iceland North Atlantic |
genre_facet |
Iceland North Atlantic |
op_relation |
http://eprints.esc.cam.ac.uk/2228/1/2011GC003748-pip.pdf http://eprints.esc.cam.ac.uk/2228/7/ggge2058.pdf http://eprints.esc.cam.ac.uk/2228/9/ggge2058-sup-0001-readme.txt http://eprints.esc.cam.ac.uk/2228/8/ggge2058-sup-0002-ds01.csv http://eprints.esc.cam.ac.uk/2228/10/ggge2058-fig-0001.png Shorttle, Oliver and Maclennan, John (2011) Compositional trends of Icelandic basalts: Implications for short–length scale lithological heterogeneity in mantle plumes. Geochemistry Geophysics Geosystems, 12. Q11008. ISSN 1525-2027 DOI https://doi.org/10.1029/2011GC003748 <https://doi.org/10.1029/2011GC003748> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1029/2011GC003748 |
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Geochemistry, Geophysics, Geosystems |
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12 |
container_issue |
11 |
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1766038622219272192 |