The response of fabric variations to simple shear and migration recrystallization
The observable microstructures in ice are the result of many dynamic and competing processes. These processes are influenced by climate variables in the firn. Layers deposited in different climate regimes may show variations in fabric which can persist deep into the ice sheet; fabric may 'remem...
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Online Access: | http://www.osti.gov/servlets/purl/1187919 https://www.osti.gov/biblio/1187919 https://doi.org/10.3189/2015JoG14J156 |
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ftosti:oai:osti.gov:1187919 2023-07-30T04:04:12+02:00 The response of fabric variations to simple shear and migration recrystallization Kennedy, Joseph H. Oak Ridge National Lab. , Oak Ridge, TN Computational Earth Sciences Group; Univ. of Alaska, Fairbanks, AK . Dept. of Physics Pettit, Erin C. Univ. of Alaska, Fairbanks, AK . Dept. of Geosciences 2016-09-20 application/pdf http://www.osti.gov/servlets/purl/1187919 https://www.osti.gov/biblio/1187919 https://doi.org/10.3189/2015JoG14J156 unknown http://www.osti.gov/servlets/purl/1187919 https://www.osti.gov/biblio/1187919 https://doi.org/10.3189/2015JoG14J156 doi:10.3189/2015JoG14J156 36 MATERIALS SCIENCE 2016 ftosti https://doi.org/10.3189/2015JoG14J156 2023-07-11T08:59:56Z The observable microstructures in ice are the result of many dynamic and competing processes. These processes are influenced by climate variables in the firn. Layers deposited in different climate regimes may show variations in fabric which can persist deep into the ice sheet; fabric may 'remember' these past climate regimes. In this paper, we model the evolution of fabric variations below the firn–ice transition and show that the addition of shear to compressive-stress regimes preserves the modeled fabric variations longer than compression-only regimes, because shear drives a positive feedback between crystal rotation and deformation. Even without shear, the modeled ice retains memory of the fabric variation for ~200 ka in typical polar ice-sheet conditions. Our model shows that temperature affects how long the fabric variation is preserved, but only affects the strain-integrated fabric evolution profile when comparing results straddling the thermal-activation-energy threshold (~–10°C). Even at high temperatures, migration recrystallization does not eliminate the modeled fabric's memory under most conditions. High levels of nearest-neighbor interactions will, however, eliminate the modeled fabric's memory more quickly than low levels of nearest-neighbor interactions. Finally, our model predicts that fabrics will retain memory of past climatic variations when subject to a wide variety of conditions found in polar ice sheets. Other/Unknown Material Ice Sheet SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Journal of Glaciology 61 227 537 550 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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36 MATERIALS SCIENCE |
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36 MATERIALS SCIENCE Kennedy, Joseph H. Oak Ridge National Lab. , Oak Ridge, TN Computational Earth Sciences Group; Univ. of Alaska, Fairbanks, AK . Dept. of Physics Pettit, Erin C. Univ. of Alaska, Fairbanks, AK . Dept. of Geosciences The response of fabric variations to simple shear and migration recrystallization |
topic_facet |
36 MATERIALS SCIENCE |
description |
The observable microstructures in ice are the result of many dynamic and competing processes. These processes are influenced by climate variables in the firn. Layers deposited in different climate regimes may show variations in fabric which can persist deep into the ice sheet; fabric may 'remember' these past climate regimes. In this paper, we model the evolution of fabric variations below the firn–ice transition and show that the addition of shear to compressive-stress regimes preserves the modeled fabric variations longer than compression-only regimes, because shear drives a positive feedback between crystal rotation and deformation. Even without shear, the modeled ice retains memory of the fabric variation for ~200 ka in typical polar ice-sheet conditions. Our model shows that temperature affects how long the fabric variation is preserved, but only affects the strain-integrated fabric evolution profile when comparing results straddling the thermal-activation-energy threshold (~–10°C). Even at high temperatures, migration recrystallization does not eliminate the modeled fabric's memory under most conditions. High levels of nearest-neighbor interactions will, however, eliminate the modeled fabric's memory more quickly than low levels of nearest-neighbor interactions. Finally, our model predicts that fabrics will retain memory of past climatic variations when subject to a wide variety of conditions found in polar ice sheets. |
author |
Kennedy, Joseph H. Oak Ridge National Lab. , Oak Ridge, TN Computational Earth Sciences Group; Univ. of Alaska, Fairbanks, AK . Dept. of Physics Pettit, Erin C. Univ. of Alaska, Fairbanks, AK . Dept. of Geosciences |
author_facet |
Kennedy, Joseph H. Oak Ridge National Lab. , Oak Ridge, TN Computational Earth Sciences Group; Univ. of Alaska, Fairbanks, AK . Dept. of Physics Pettit, Erin C. Univ. of Alaska, Fairbanks, AK . Dept. of Geosciences |
author_sort |
Kennedy, Joseph H. Oak Ridge National Lab. , Oak Ridge, TN |
title |
The response of fabric variations to simple shear and migration recrystallization |
title_short |
The response of fabric variations to simple shear and migration recrystallization |
title_full |
The response of fabric variations to simple shear and migration recrystallization |
title_fullStr |
The response of fabric variations to simple shear and migration recrystallization |
title_full_unstemmed |
The response of fabric variations to simple shear and migration recrystallization |
title_sort |
response of fabric variations to simple shear and migration recrystallization |
publishDate |
2016 |
url |
http://www.osti.gov/servlets/purl/1187919 https://www.osti.gov/biblio/1187919 https://doi.org/10.3189/2015JoG14J156 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_relation |
http://www.osti.gov/servlets/purl/1187919 https://www.osti.gov/biblio/1187919 https://doi.org/10.3189/2015JoG14J156 doi:10.3189/2015JoG14J156 |
op_doi |
https://doi.org/10.3189/2015JoG14J156 |
container_title |
Journal of Glaciology |
container_volume |
61 |
container_issue |
227 |
container_start_page |
537 |
op_container_end_page |
550 |
_version_ |
1772815447040720896 |