Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica
Ice rheology governs how glaciers flow and respond to environmental change. The rheology of glacier ice evolves in response to a variety of mechanisms, including damage, heating, melting and the development of crystalline fabric. The relative contributions of these rheological mechanisms are not wel...
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ftcaltechauth:oai:authors.library.caltech.edu:12czx-gpj38 2024-09-15T17:43:01+00:00 Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark 2018-08 https://doi.org/10.1017/jog.2018.47 unknown International Glaciological Society https://doi.org/10.1017/jog.2018.47 oai:authors.library.caltech.edu:12czx-gpj38 eprintid:89579 resolverid:CaltechAUTHORS:20180912-135248522 info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode Journal of Glaciology, 64(246), 583-594, (2018-08) Anisotropic ice flow Antarctic glaciology glacial rheology glacier flow ice rheology info:eu-repo/semantics/article 2018 ftcaltechauth https://doi.org/10.1017/jog.2018.47 2024-08-06T15:35:04Z Ice rheology governs how glaciers flow and respond to environmental change. The rheology of glacier ice evolves in response to a variety of mechanisms, including damage, heating, melting and the development of crystalline fabric. The relative contributions of these rheological mechanisms are not well understood. Using remotely sensed data and physical models, we decouple the influence of each of the aforementioned mechanisms along the margins of Rutford Ice Stream, a laterally confined outlet glacier in West Antarctica. We show that fabric is an important control on ice rheology in the shear margins, with an inferred softening effect consistent with a single-maximum fabric. Fabric evolves to steady state near the onset of streaming flow, and ice progressively softens downstream almost exclusively due to shear heating. The rate of heating is sensitive to local shear strain rates, which respond to local changes in bed topography as ice is squeezed through the basal trough. The impact of shear heating on the downstream evolution of ice rheology in a laterally confined glacier suggests that the thermoviscous feedback – wherein faster ice flow leads to higher rates of shear heating, further softening the ice – is a fundamental control on glacier dynamics. © The Author(s) 2018. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Published online: 07 June 2018. We thank Carlos Martin, Robert Arthern, Jenny Suckale, Cooper Elsworth and James Rice for insightful conversations. We also thank two anonymous reviewers for helpful comments. B.M.M. was funded by an NSF Earth Sciences Postdoctoral Fellowship award EAR-1452587. C.R.M. was supported by an NSF Graduate Research Fellowship, award DGE-1144152 and a David Crighton Fellowship. A.A.R. was funded through a NOAA Climate & Global Change ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica Caltech Authors (California Institute of Technology) Journal of Glaciology 64 246 583 594 |
institution |
Open Polar |
collection |
Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
unknown |
topic |
Anisotropic ice flow Antarctic glaciology glacial rheology glacier flow ice rheology |
spellingShingle |
Anisotropic ice flow Antarctic glaciology glacial rheology glacier flow ice rheology Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
topic_facet |
Anisotropic ice flow Antarctic glaciology glacial rheology glacier flow ice rheology |
description |
Ice rheology governs how glaciers flow and respond to environmental change. The rheology of glacier ice evolves in response to a variety of mechanisms, including damage, heating, melting and the development of crystalline fabric. The relative contributions of these rheological mechanisms are not well understood. Using remotely sensed data and physical models, we decouple the influence of each of the aforementioned mechanisms along the margins of Rutford Ice Stream, a laterally confined outlet glacier in West Antarctica. We show that fabric is an important control on ice rheology in the shear margins, with an inferred softening effect consistent with a single-maximum fabric. Fabric evolves to steady state near the onset of streaming flow, and ice progressively softens downstream almost exclusively due to shear heating. The rate of heating is sensitive to local shear strain rates, which respond to local changes in bed topography as ice is squeezed through the basal trough. The impact of shear heating on the downstream evolution of ice rheology in a laterally confined glacier suggests that the thermoviscous feedback – wherein faster ice flow leads to higher rates of shear heating, further softening the ice – is a fundamental control on glacier dynamics. © The Author(s) 2018. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Published online: 07 June 2018. We thank Carlos Martin, Robert Arthern, Jenny Suckale, Cooper Elsworth and James Rice for insightful conversations. We also thank two anonymous reviewers for helpful comments. B.M.M. was funded by an NSF Earth Sciences Postdoctoral Fellowship award EAR-1452587. C.R.M. was supported by an NSF Graduate Research Fellowship, award DGE-1144152 and a David Crighton Fellowship. A.A.R. was funded through a NOAA Climate & Global Change ... |
format |
Article in Journal/Newspaper |
author |
Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark |
author_facet |
Minchew, Brent M. Meyer, Colin R. Robel, Alexander A. Gudmundsson, G. Hilmar Simons, Mark |
author_sort |
Minchew, Brent M. |
title |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_short |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_full |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_fullStr |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_full_unstemmed |
Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica |
title_sort |
processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on rutford ice stream, west antarctica |
publisher |
International Glaciological Society |
publishDate |
2018 |
url |
https://doi.org/10.1017/jog.2018.47 |
genre |
Antarc* Antarctic Antarctica Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica |
op_source |
Journal of Glaciology, 64(246), 583-594, (2018-08) |
op_relation |
https://doi.org/10.1017/jog.2018.47 oai:authors.library.caltech.edu:12czx-gpj38 eprintid:89579 resolverid:CaltechAUTHORS:20180912-135248522 |
op_rights |
info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode |
op_doi |
https://doi.org/10.1017/jog.2018.47 |
container_title |
Journal of Glaciology |
container_volume |
64 |
container_issue |
246 |
container_start_page |
583 |
op_container_end_page |
594 |
_version_ |
1810489842851643392 |