Mafic tiers and transient mushes: evidence from Iceland
It is well established that magmatism is trans-crustal, with melt storage and processing occurring over a range of depths. Development of this conceptual model was based on observations of the products of magmatism at spreading ridges, including Iceland. Petrological barometry and tracking of the so...
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Online Access: | http://eprints.esc.cam.ac.uk/4377/ http://eprints.esc.cam.ac.uk/4377/1/rsta.2018.0021.pdf https://doi.org/10.1098/rsta.2018.0021 |
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ftucambridgeesc:oai:eprints.esc.cam.ac.uk:4377 2023-05-15T16:47:04+02:00 Mafic tiers and transient mushes: evidence from Iceland Maclennan, J. 2019 text http://eprints.esc.cam.ac.uk/4377/ http://eprints.esc.cam.ac.uk/4377/1/rsta.2018.0021.pdf https://doi.org/10.1098/rsta.2018.0021 en eng The Royal Society http://eprints.esc.cam.ac.uk/4377/1/rsta.2018.0021.pdf Maclennan, J. (2019) Mafic tiers and transient mushes: evidence from Iceland. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 377 (2139). p. 20180021. ISSN 1364-503X DOI https://doi.org/10.1098/rsta.2018.0021 <https://doi.org/10.1098/rsta.2018.0021> 05 - Petrology - Igneous Metamorphic and Volcanic Studies Article PeerReviewed 2019 ftucambridgeesc https://doi.org/10.1098/rsta.2018.0021 2020-08-27T18:09:58Z It is well established that magmatism is trans-crustal, with melt storage and processing occurring over a range of depths. Development of this conceptual model was based on observations of the products of magmatism at spreading ridges, including Iceland. Petrological barometry and tracking of the solidification process has been used to show that the Icelandic crust is built by crystallization over a range of depths. The available petrological evidence indicates that most of the active rift zones are not underlain by extensive and pervasive crystal mush. Instead, the microanalytical observations from Iceland are consistent with a model where magmatic processing in the lower crust occurs in sills of decimetric vertical thickness. This stacked sills mode of crustal accretion corresponds to that proposed for the oceanic crust on the basis of ophiolite studies. A key feature of these models is that the country rock for the sills is hot but subsolidus. This condition can be met if the porosity in thin crystal mushes at the margins of the sills is occluded by primitive phases, a contention that is consistent with observations from cumulate nodules in Icelandic basalts. The conditions required for the stabilization of trans-crustal mushes may not be present in magmatic systems at spreading ridges. This article is part of the Theo Murphy meeting issue ‘Magma reservoir architecture and dynamics’. Article in Journal/Newspaper Iceland University of Cambridge, Department of Earth Sciences: ESC Publications Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377 2139 20180021 |
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University of Cambridge, Department of Earth Sciences: ESC Publications |
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English |
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05 - Petrology - Igneous Metamorphic and Volcanic Studies |
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05 - Petrology - Igneous Metamorphic and Volcanic Studies Maclennan, J. Mafic tiers and transient mushes: evidence from Iceland |
topic_facet |
05 - Petrology - Igneous Metamorphic and Volcanic Studies |
description |
It is well established that magmatism is trans-crustal, with melt storage and processing occurring over a range of depths. Development of this conceptual model was based on observations of the products of magmatism at spreading ridges, including Iceland. Petrological barometry and tracking of the solidification process has been used to show that the Icelandic crust is built by crystallization over a range of depths. The available petrological evidence indicates that most of the active rift zones are not underlain by extensive and pervasive crystal mush. Instead, the microanalytical observations from Iceland are consistent with a model where magmatic processing in the lower crust occurs in sills of decimetric vertical thickness. This stacked sills mode of crustal accretion corresponds to that proposed for the oceanic crust on the basis of ophiolite studies. A key feature of these models is that the country rock for the sills is hot but subsolidus. This condition can be met if the porosity in thin crystal mushes at the margins of the sills is occluded by primitive phases, a contention that is consistent with observations from cumulate nodules in Icelandic basalts. The conditions required for the stabilization of trans-crustal mushes may not be present in magmatic systems at spreading ridges. This article is part of the Theo Murphy meeting issue ‘Magma reservoir architecture and dynamics’. |
format |
Article in Journal/Newspaper |
author |
Maclennan, J. |
author_facet |
Maclennan, J. |
author_sort |
Maclennan, J. |
title |
Mafic tiers and transient mushes: evidence from Iceland |
title_short |
Mafic tiers and transient mushes: evidence from Iceland |
title_full |
Mafic tiers and transient mushes: evidence from Iceland |
title_fullStr |
Mafic tiers and transient mushes: evidence from Iceland |
title_full_unstemmed |
Mafic tiers and transient mushes: evidence from Iceland |
title_sort |
mafic tiers and transient mushes: evidence from iceland |
publisher |
The Royal Society |
publishDate |
2019 |
url |
http://eprints.esc.cam.ac.uk/4377/ http://eprints.esc.cam.ac.uk/4377/1/rsta.2018.0021.pdf https://doi.org/10.1098/rsta.2018.0021 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
http://eprints.esc.cam.ac.uk/4377/1/rsta.2018.0021.pdf Maclennan, J. (2019) Mafic tiers and transient mushes: evidence from Iceland. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 377 (2139). p. 20180021. ISSN 1364-503X DOI https://doi.org/10.1098/rsta.2018.0021 <https://doi.org/10.1098/rsta.2018.0021> |
op_doi |
https://doi.org/10.1098/rsta.2018.0021 |
container_title |
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
container_volume |
377 |
container_issue |
2139 |
container_start_page |
20180021 |
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1766037158034931712 |