The Skaergaard trough layering: sedimentation in a convecting magma chamber
This is the final version of the article. Available from Springer verlag via the DOI in this record. The upper parts of the floor cumulates of the Skaergaard Intrusion, East Greenland, contain abundant features known as troughs. The troughs are gently plunging synformal structures comprising stacks...
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ftunivexeter:oai:ore.exeter.ac.uk:10871/32898 2024-09-09T19:38:46+00:00 The Skaergaard trough layering: sedimentation in a convecting magma chamber Vukmanovic, Z Holness, MB Monks, K Andersen, JCØ 2018 http://hdl.handle.net/10871/32898 https://doi.org/10.1007/s00410-018-1466-1 en eng Springer Verlag Vol. 173, (43) pp. 1-18 doi:10.1007/s00410-018-1466-1 http://hdl.handle.net/10871/32898 0010-7999 Contributions to Mineralogy and Petrology This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat ivecommons .org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Skaergaard intrusion Trough layering Texture analysis EBSD Article 2018 ftunivexeter https://doi.org/10.1007/s00410-018-1466-1 2024-07-29T03:24:16Z This is the final version of the article. Available from Springer verlag via the DOI in this record. The upper parts of the floor cumulates of the Skaergaard Intrusion, East Greenland, contain abundant features known as troughs. The troughs are gently plunging synformal structures comprising stacks of crescentic modally graded layers with a sharply defined mafic base that grades upward into plagioclase-rich material. The origin of the troughs and layering is contentious, attributed variously to deposition of mineral grains by magmatic currents descending from the nearby walls, or to in situ development by localised recrystallisation during gravitationally-driven compaction. They are characterised by outcrop-scale features such as mineral lineations parallel to the trough axis, evidence of erosion and layer truncation associated with migration of the trough axis, and disruption of layering by syn-magmatic slumping. A detailed microstructural study of the modal trough layers, using electron backscatter diffraction together with geochemical mapping, demonstrates that these rocks do not record evidence for deformation by either dislocation creep or dissolution–reprecipitation. Instead, the troughs are characterised by the alignment of euhedral plagioclase crystals with unmodified primary igneous compositional zoning. We argue that the lineations and foliations are, therefore, a consequence of grain alignment during magmatic flow. Post-accumulation amplification of the modal layering occurred as a result of differential migration of an unmixed immiscible interstitial liquid, with upwards migration of the Si-rich conjugate into the plagioclase-rich upper part of the layers, whereas the Fe-rich immiscible conjugate remained in the mafic base. Both field and microstructure evidence support the origin of the troughs as the sites of repeated deposition from crystal-rich currents descending from the nearby chamber walls. ZV is supported by a Marie Curie Individual Fellowship. We also acknowledge financial support from ... Article in Journal/Newspaper East Greenland Greenland University of Exeter: Open Research Exeter (ORE) Greenland Contributions to Mineralogy and Petrology 173 5 |
institution |
Open Polar |
collection |
University of Exeter: Open Research Exeter (ORE) |
op_collection_id |
ftunivexeter |
language |
English |
topic |
The Skaergaard intrusion Trough layering Texture analysis EBSD |
spellingShingle |
The Skaergaard intrusion Trough layering Texture analysis EBSD Vukmanovic, Z Holness, MB Monks, K Andersen, JCØ The Skaergaard trough layering: sedimentation in a convecting magma chamber |
topic_facet |
The Skaergaard intrusion Trough layering Texture analysis EBSD |
description |
This is the final version of the article. Available from Springer verlag via the DOI in this record. The upper parts of the floor cumulates of the Skaergaard Intrusion, East Greenland, contain abundant features known as troughs. The troughs are gently plunging synformal structures comprising stacks of crescentic modally graded layers with a sharply defined mafic base that grades upward into plagioclase-rich material. The origin of the troughs and layering is contentious, attributed variously to deposition of mineral grains by magmatic currents descending from the nearby walls, or to in situ development by localised recrystallisation during gravitationally-driven compaction. They are characterised by outcrop-scale features such as mineral lineations parallel to the trough axis, evidence of erosion and layer truncation associated with migration of the trough axis, and disruption of layering by syn-magmatic slumping. A detailed microstructural study of the modal trough layers, using electron backscatter diffraction together with geochemical mapping, demonstrates that these rocks do not record evidence for deformation by either dislocation creep or dissolution–reprecipitation. Instead, the troughs are characterised by the alignment of euhedral plagioclase crystals with unmodified primary igneous compositional zoning. We argue that the lineations and foliations are, therefore, a consequence of grain alignment during magmatic flow. Post-accumulation amplification of the modal layering occurred as a result of differential migration of an unmixed immiscible interstitial liquid, with upwards migration of the Si-rich conjugate into the plagioclase-rich upper part of the layers, whereas the Fe-rich immiscible conjugate remained in the mafic base. Both field and microstructure evidence support the origin of the troughs as the sites of repeated deposition from crystal-rich currents descending from the nearby chamber walls. ZV is supported by a Marie Curie Individual Fellowship. We also acknowledge financial support from ... |
format |
Article in Journal/Newspaper |
author |
Vukmanovic, Z Holness, MB Monks, K Andersen, JCØ |
author_facet |
Vukmanovic, Z Holness, MB Monks, K Andersen, JCØ |
author_sort |
Vukmanovic, Z |
title |
The Skaergaard trough layering: sedimentation in a convecting magma chamber |
title_short |
The Skaergaard trough layering: sedimentation in a convecting magma chamber |
title_full |
The Skaergaard trough layering: sedimentation in a convecting magma chamber |
title_fullStr |
The Skaergaard trough layering: sedimentation in a convecting magma chamber |
title_full_unstemmed |
The Skaergaard trough layering: sedimentation in a convecting magma chamber |
title_sort |
skaergaard trough layering: sedimentation in a convecting magma chamber |
publisher |
Springer Verlag |
publishDate |
2018 |
url |
http://hdl.handle.net/10871/32898 https://doi.org/10.1007/s00410-018-1466-1 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
East Greenland Greenland |
genre_facet |
East Greenland Greenland |
op_relation |
Vol. 173, (43) pp. 1-18 doi:10.1007/s00410-018-1466-1 http://hdl.handle.net/10871/32898 0010-7999 Contributions to Mineralogy and Petrology |
op_rights |
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat ivecommons .org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. |
op_doi |
https://doi.org/10.1007/s00410-018-1466-1 |
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Contributions to Mineralogy and Petrology |
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173 |
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