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Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden
Magma transport through the Earth’s crust occurs dominantly via sheet intrusions, such as dykes and cone-sheets, and is fundamental to crustal evolution, volcanic eruptions and geochemical element cycling. However, reliable methods to reconstruct flow direction in solidified sheet intrusions have pr...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4901264/ https://www.ncbi.nlm.nih.gov/pubmed/27282420 http://dx.doi.org/10.1038/srep27635 |
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author | Andersson, Magnus Almqvist, Bjarne S. G. Burchardt, Steffi Troll, Valentin R. Malehmir, Alireza Snowball, Ian Kübler, Lutz |
author_facet | Andersson, Magnus Almqvist, Bjarne S. G. Burchardt, Steffi Troll, Valentin R. Malehmir, Alireza Snowball, Ian Kübler, Lutz |
author_sort | Andersson, Magnus |
collection | PubMed |
description | Magma transport through the Earth’s crust occurs dominantly via sheet intrusions, such as dykes and cone-sheets, and is fundamental to crustal evolution, volcanic eruptions and geochemical element cycling. However, reliable methods to reconstruct flow direction in solidified sheet intrusions have proved elusive. Anisotropy of magnetic susceptibility (AMS) in magmatic sheets is often interpreted as primary magma flow, but magnetic fabrics can be modified by post-emplacement processes, making interpretation of AMS data ambiguous. Here we present AMS data from cone-sheets in the Alnö carbonatite complex, central Sweden. We discuss six scenarios of syn- and post-emplacement processes that can modify AMS fabrics and offer a conceptual framework for systematic interpretation of magma movements in sheet intrusions. The AMS fabrics in the Alnö cone-sheets are dominantly oblate with magnetic foliations parallel to sheet orientations. These fabrics may result from primary lateral flow or from sheet closure at the terminal stage of magma transport. As the cone-sheets are discontinuous along their strike direction, sheet closure is the most probable process to explain the observed AMS fabrics. We argue that these fabrics may be common to cone-sheets and an integrated geology, petrology and AMS approach can be used to distinguish them from primary flow fabrics. |
format | Online Article Text |
id | pubmed-4901264 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-49012642016-06-13 Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden Andersson, Magnus Almqvist, Bjarne S. G. Burchardt, Steffi Troll, Valentin R. Malehmir, Alireza Snowball, Ian Kübler, Lutz Sci Rep Article Magma transport through the Earth’s crust occurs dominantly via sheet intrusions, such as dykes and cone-sheets, and is fundamental to crustal evolution, volcanic eruptions and geochemical element cycling. However, reliable methods to reconstruct flow direction in solidified sheet intrusions have proved elusive. Anisotropy of magnetic susceptibility (AMS) in magmatic sheets is often interpreted as primary magma flow, but magnetic fabrics can be modified by post-emplacement processes, making interpretation of AMS data ambiguous. Here we present AMS data from cone-sheets in the Alnö carbonatite complex, central Sweden. We discuss six scenarios of syn- and post-emplacement processes that can modify AMS fabrics and offer a conceptual framework for systematic interpretation of magma movements in sheet intrusions. The AMS fabrics in the Alnö cone-sheets are dominantly oblate with magnetic foliations parallel to sheet orientations. These fabrics may result from primary lateral flow or from sheet closure at the terminal stage of magma transport. As the cone-sheets are discontinuous along their strike direction, sheet closure is the most probable process to explain the observed AMS fabrics. We argue that these fabrics may be common to cone-sheets and an integrated geology, petrology and AMS approach can be used to distinguish them from primary flow fabrics. Nature Publishing Group 2016-06-10 /pmc/articles/PMC4901264/ /pubmed/27282420 http://dx.doi.org/10.1038/srep27635 Text en Copyright © 2016, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
spellingShingle | Article Andersson, Magnus Almqvist, Bjarne S. G. Burchardt, Steffi Troll, Valentin R. Malehmir, Alireza Snowball, Ian Kübler, Lutz Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden |
title | Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden |
title_full | Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden |
title_fullStr | Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden |
title_full_unstemmed | Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden |
title_short | Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden |
title_sort | magma transport in sheet intrusions of the alnö carbonatite complex, central sweden |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4901264/ https://www.ncbi.nlm.nih.gov/pubmed/27282420 http://dx.doi.org/10.1038/srep27635 |
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