Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden
Microstructures provide key insights into understanding the mechanical behavior of ice. Crystallographic preferred orientation (CPO) develops during plastic deformation as ice deforms dominantly by dislocation glide on the basal plane, modified and often intensified by dynamic recrystallization. CPO...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00055362 2024-09-15T18:39:00+00:00 Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden Monz, Morgan E. Hudleston, Peter J. Prior, David J. Michels, Zachary Fan, Sheng Negrini, Marianne Langhorne, Pat J. Qi, Chao 2021-01 electronic https://doi.org/10.5194/tc-15-303-2021 https://noa.gwlb.de/receive/cop_mods_00055362 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00055013/tc-15-303-2021.pdf https://tc.copernicus.org/articles/15/303/2021/tc-15-303-2021.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-15-303-2021 https://noa.gwlb.de/receive/cop_mods_00055362 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00055013/tc-15-303-2021.pdf https://tc.copernicus.org/articles/15/303/2021/tc-15-303-2021.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2021 ftnonlinearchiv https://doi.org/10.5194/tc-15-303-2021 2024-06-26T04:41:37Z Microstructures provide key insights into understanding the mechanical behavior of ice. Crystallographic preferred orientation (CPO) develops during plastic deformation as ice deforms dominantly by dislocation glide on the basal plane, modified and often intensified by dynamic recrystallization. CPO patterns in fine-grained ice have been relatively well characterized and understood in experiments and nature, whereas CPO patterns in “warm” ( T>-10∘C), coarse-grained, natural ice remain enigmatic. Previous microstructural studies of coarse-grained ice have been limited to c-axis orientations using light optical measurements. We present the first study of a axes as well as c axes in such ice by application of cryo-electron backscatter diffraction (EBSD) and do so in a shear-dominated setting. We have done this by developing a new sample preparation technique of constructing composite sections, to allow us to use EBSD to obtain a representative, bulk CPO on coarse-grained ice. We draw attention to the well-known issue of interlocking grains of complex shape and suggest that a grain sampling bias of large, branching crystals that appear multiple times as island grains in thin sections may result in the typical multimaxima CPOs previously identified in warm, coarse-grained ice that has been subjected to prolonged shear. CPOs combined from multiple samples of highly sheared ice from Storglaciären provide a more comprehensive picture of the microstructure and yield a pronounced cluster of c axes sub-normal to the shear plane and elongate or split in a plane normal to the shear direction as well as a concomitant girdle of a axes parallel to the shear plane with a maximum perpendicular to the shear direction. This pattern compares well with patterns produced by subsampling datasets from ice sheared in laboratory experiments at high homologous temperatures up to strains of ∼1.5. Shear strains in the margin of Storglaciären are much higher than those in experimental work. At much lower natural strain rates, dynamic ... Article in Journal/Newspaper The Cryosphere Niedersächsisches Online-Archiv NOA The Cryosphere 15 1 303 324 |
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article Verlagsveröffentlichung Monz, Morgan E. Hudleston, Peter J. Prior, David J. Michels, Zachary Fan, Sheng Negrini, Marianne Langhorne, Pat J. Qi, Chao Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden |
topic_facet |
article Verlagsveröffentlichung |
description |
Microstructures provide key insights into understanding the mechanical behavior of ice. Crystallographic preferred orientation (CPO) develops during plastic deformation as ice deforms dominantly by dislocation glide on the basal plane, modified and often intensified by dynamic recrystallization. CPO patterns in fine-grained ice have been relatively well characterized and understood in experiments and nature, whereas CPO patterns in “warm” ( T>-10∘C), coarse-grained, natural ice remain enigmatic. Previous microstructural studies of coarse-grained ice have been limited to c-axis orientations using light optical measurements. We present the first study of a axes as well as c axes in such ice by application of cryo-electron backscatter diffraction (EBSD) and do so in a shear-dominated setting. We have done this by developing a new sample preparation technique of constructing composite sections, to allow us to use EBSD to obtain a representative, bulk CPO on coarse-grained ice. We draw attention to the well-known issue of interlocking grains of complex shape and suggest that a grain sampling bias of large, branching crystals that appear multiple times as island grains in thin sections may result in the typical multimaxima CPOs previously identified in warm, coarse-grained ice that has been subjected to prolonged shear. CPOs combined from multiple samples of highly sheared ice from Storglaciären provide a more comprehensive picture of the microstructure and yield a pronounced cluster of c axes sub-normal to the shear plane and elongate or split in a plane normal to the shear direction as well as a concomitant girdle of a axes parallel to the shear plane with a maximum perpendicular to the shear direction. This pattern compares well with patterns produced by subsampling datasets from ice sheared in laboratory experiments at high homologous temperatures up to strains of ∼1.5. Shear strains in the margin of Storglaciären are much higher than those in experimental work. At much lower natural strain rates, dynamic ... |
format |
Article in Journal/Newspaper |
author |
Monz, Morgan E. Hudleston, Peter J. Prior, David J. Michels, Zachary Fan, Sheng Negrini, Marianne Langhorne, Pat J. Qi, Chao |
author_facet |
Monz, Morgan E. Hudleston, Peter J. Prior, David J. Michels, Zachary Fan, Sheng Negrini, Marianne Langhorne, Pat J. Qi, Chao |
author_sort |
Monz, Morgan E. |
title |
Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden |
title_short |
Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden |
title_full |
Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden |
title_fullStr |
Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden |
title_full_unstemmed |
Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden |
title_sort |
full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, storglaciären, sweden |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-303-2021 https://noa.gwlb.de/receive/cop_mods_00055362 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00055013/tc-15-303-2021.pdf https://tc.copernicus.org/articles/15/303/2021/tc-15-303-2021.pdf |
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The Cryosphere |
genre_facet |
The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-15-303-2021 https://noa.gwlb.de/receive/cop_mods_00055362 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00055013/tc-15-303-2021.pdf https://tc.copernicus.org/articles/15/303/2021/tc-15-303-2021.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-15-303-2021 |
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The Cryosphere |
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15 |
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1 |
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303 |
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324 |
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1810483394297987072 |