The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis
The flow of ice depends on the properties of the aggregate of individual ice crystals, such as grain size or lattice orientation distributions. Therefore, an understanding of the processes controlling ice micro-dynamics is needed to ultimately develop a physically based macroscopic ice flow law. We...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/355991 2023-07-23T04:19:37+02:00 The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis Steinbach, F. Kuiper, E.N. Eichler, J. Bons, P. D. Drury, M. R. Griera, A. Pennock, G.M. Weikusat, I. Structural geology and EM Structural geology & tectonics 2017-09-26 image/pdf https://dspace.library.uu.nl/handle/1874/355991 en eng 2296-6463 https://dspace.library.uu.nl/handle/1874/355991 info:eu-repo/semantics/OpenAccess ice microstructure modeling cryo-ebsd fabric analyser ice deformation dynamic recrystallization grain size evolution grain dissection neem ice core Article 2017 ftunivutrecht 2023-07-02T02:13:27Z The flow of ice depends on the properties of the aggregate of individual ice crystals, such as grain size or lattice orientation distributions. Therefore, an understanding of the processes controlling ice micro-dynamics is needed to ultimately develop a physically based macroscopic ice flow law. We investigated the relevance of the process of grain dissection as a grain-size-modifying process in natural ice. For that purpose, we performed numerical multi-process microstructure modeling and analyzed microstructure and crystallographic orientation maps from natural deep ice-core samples from the North Greenland Eemian Ice Drilling (NEEM) project. Full crystallographic orientations measured by electron backscatter diffraction (EBSD) have been used together with c-axis orientations using an optical technique (Fabric Analyser). Grain dissection is a feature of strain-induced grain boundary migration. During grain dissection, grain boundaries bulge into a neighboring grain in an area of high dislocation energy and merge with the opposite grain boundary. This splits the high dislocation-energy grain into two parts, effectively decreasing the local grain size. Currently, grain size reduction in ice is thought to be achieved by either the progressive transformation from dislocation walls into new high-angle grain boundaries, called subgrain rotation or polygonisation, or bulging nucleation that is assisted by subgrain rotation. Both our time-resolved numerical modeling and NEEM ice core samples show that grain dissection is a common mechanism during ice deformation and can provide an efficient process to reduce grain sizes and counter-act dynamic grain-growth in addition to polygonisation or bulging nucleation. Thus, our results show that solely strain-induced boundary migration, in absence of subgrain rotation, can reduce grain sizes in polar ice, in particular if strain energy gradients are high. We describe the microstructural characteristics that can be used to identify grain dissection in natural microstructures. Article in Journal/Newspaper Greenland ice core North Greenland Utrecht University Repository Greenland |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
ice microstructure modeling cryo-ebsd fabric analyser ice deformation dynamic recrystallization grain size evolution grain dissection neem ice core |
spellingShingle |
ice microstructure modeling cryo-ebsd fabric analyser ice deformation dynamic recrystallization grain size evolution grain dissection neem ice core Steinbach, F. Kuiper, E.N. Eichler, J. Bons, P. D. Drury, M. R. Griera, A. Pennock, G.M. Weikusat, I. The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis |
topic_facet |
ice microstructure modeling cryo-ebsd fabric analyser ice deformation dynamic recrystallization grain size evolution grain dissection neem ice core |
description |
The flow of ice depends on the properties of the aggregate of individual ice crystals, such as grain size or lattice orientation distributions. Therefore, an understanding of the processes controlling ice micro-dynamics is needed to ultimately develop a physically based macroscopic ice flow law. We investigated the relevance of the process of grain dissection as a grain-size-modifying process in natural ice. For that purpose, we performed numerical multi-process microstructure modeling and analyzed microstructure and crystallographic orientation maps from natural deep ice-core samples from the North Greenland Eemian Ice Drilling (NEEM) project. Full crystallographic orientations measured by electron backscatter diffraction (EBSD) have been used together with c-axis orientations using an optical technique (Fabric Analyser). Grain dissection is a feature of strain-induced grain boundary migration. During grain dissection, grain boundaries bulge into a neighboring grain in an area of high dislocation energy and merge with the opposite grain boundary. This splits the high dislocation-energy grain into two parts, effectively decreasing the local grain size. Currently, grain size reduction in ice is thought to be achieved by either the progressive transformation from dislocation walls into new high-angle grain boundaries, called subgrain rotation or polygonisation, or bulging nucleation that is assisted by subgrain rotation. Both our time-resolved numerical modeling and NEEM ice core samples show that grain dissection is a common mechanism during ice deformation and can provide an efficient process to reduce grain sizes and counter-act dynamic grain-growth in addition to polygonisation or bulging nucleation. Thus, our results show that solely strain-induced boundary migration, in absence of subgrain rotation, can reduce grain sizes in polar ice, in particular if strain energy gradients are high. We describe the microstructural characteristics that can be used to identify grain dissection in natural microstructures. |
author2 |
Structural geology and EM Structural geology & tectonics |
format |
Article in Journal/Newspaper |
author |
Steinbach, F. Kuiper, E.N. Eichler, J. Bons, P. D. Drury, M. R. Griera, A. Pennock, G.M. Weikusat, I. |
author_facet |
Steinbach, F. Kuiper, E.N. Eichler, J. Bons, P. D. Drury, M. R. Griera, A. Pennock, G.M. Weikusat, I. |
author_sort |
Steinbach, F. |
title |
The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis |
title_short |
The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis |
title_full |
The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis |
title_fullStr |
The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis |
title_full_unstemmed |
The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insight from Numerical Models and Ice Core Microstructure Analysis |
title_sort |
relevance of grain dissection for grain size reduction in polar ice: insight from numerical models and ice core microstructure analysis |
publishDate |
2017 |
url |
https://dspace.library.uu.nl/handle/1874/355991 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland ice core North Greenland |
genre_facet |
Greenland ice core North Greenland |
op_relation |
2296-6463 https://dspace.library.uu.nl/handle/1874/355991 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772182880129122304 |