Processes controlling the downstream evolution of ice rheology in glacier shear margins: case study on Rutford Ice Stream, West Antarctica
ABSTRACT 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 ar...
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Language: | English |
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Online Access: | http://dx.doi.org/10.1017/jog.2018.47 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143018000473 |
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crcambridgeupr:10.1017/jog.2018.47 2024-06-23T07:46:28+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 http://dx.doi.org/10.1017/jog.2018.47 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143018000473 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 64, issue 246, page 583-594 ISSN 0022-1430 1727-5652 journal-article 2018 crcambridgeupr https://doi.org/10.1017/jog.2018.47 2024-06-05T04:04:35Z ABSTRACT 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. Article in Journal/Newspaper Antarc* Antarctica Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica Cambridge University Press West Antarctica Rutford ENVELOPE(-85.300,-85.300,-78.600,-78.600) Rutford Ice Stream ENVELOPE(-80.000,-80.000,-79.167,-79.167) Journal of Glaciology 64 246 583 594 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
ABSTRACT 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. |
format |
Article in Journal/Newspaper |
author |
MINCHEW, BRENT M. MEYER, COLIN R. ROBEL, ALEXANDER A. GUDMUNDSSON, G. HILMAR SIMONS, MARK |
spellingShingle |
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 |
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 |
Cambridge University Press (CUP) |
publishDate |
2018 |
url |
http://dx.doi.org/10.1017/jog.2018.47 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143018000473 |
long_lat |
ENVELOPE(-85.300,-85.300,-78.600,-78.600) ENVELOPE(-80.000,-80.000,-79.167,-79.167) |
geographic |
West Antarctica Rutford Rutford Ice Stream |
geographic_facet |
West Antarctica Rutford Rutford Ice Stream |
genre |
Antarc* Antarctica Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica |
genre_facet |
Antarc* Antarctica Ice Stream A Journal of Glaciology Rutford Ice Stream West Antarctica |
op_source |
Journal of Glaciology volume 64, issue 246, page 583-594 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
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_ |
1802646207045042176 |