Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes
<p>Topographic highs (“bumps”) across glaciated landscapes have the potential to temporarily slow ice sheet flow or, conversely, accelerate ice flow through subglacial strain heating and meltwater production. Isolated bumps of variable size across the deglaciated landscape of the Cordilleran I...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-06-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/17/2477/2023/tc-17-2477-2023.pdf |
| _version_ | 1797797705474375680 |
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| author | M. A. McKenzie L. E. Miller J. S. Slawson J. S. Slawson E. J. MacKie S. Wang |
| author_facet | M. A. McKenzie L. E. Miller J. S. Slawson J. S. Slawson E. J. MacKie S. Wang |
| author_sort | M. A. McKenzie |
| collection | DOAJ |
| description | <p>Topographic highs (“bumps”) across glaciated landscapes have the
potential to temporarily slow ice sheet flow or, conversely, accelerate ice
flow through subglacial strain heating and meltwater production. Isolated
bumps of variable size across the deglaciated landscape of the Cordilleran
Ice Sheet (CIS) of Washington State present an opportunity to study the
influence of topographic highs on ice–bed interactions and ice flow
organization. This work utilizes semi-automatic mapping techniques of
subglacial bedforms to characterize the morphology of streamlined subglacial
bedforms including elongation, surface relief, and orientation, all of which
provide insight into subglacial processes during post-Last Glacial Maximum
deglaciation. We identify a bump-size threshold of several cubic kilometers
– around 4.5 km<span class="inline-formula"><sup>3</sup></span> – in which bumps larger than this size will
consistently and significantly disrupt both ice flow organization and
subglacial sedimentary processes, which are fundamental to the genesis of
streamlined subglacial bedforms. Additionally, sedimentary processes are
persistent and well developed downstream of bumps, as reflected by enhanced
bedform elongation and reduced surface relief, likely due to increased
availability and production of subglacial sediment and meltwater. While
isolated topography plays a role in disrupting ice flow, larger bumps have a
greater disruption to ice flow organization, while bumps below the
identified threshold seem to have little effect on ice and subglacial
processes. The variable influence of isolated topographic bumps on ice flow
of the CIS has significant implications for outlet glaciers of the Greenland
Ice Sheet (GrIS) due to similarities in regional topography, where local
bumps are largely unresolved.</p> |
| first_indexed | 2024-03-13T03:52:24Z |
| format | Article |
| id | doaj.art-f8ef117e7cf6453d9392491e0729f2ee |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-03-13T03:52:24Z |
| publishDate | 2023-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-f8ef117e7cf6453d9392491e0729f2ee2023-06-22T12:22:16ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242023-06-01172477248610.5194/tc-17-2477-2023Differential impact of isolated topographic bumps on ice sheet flow and subglacial processesM. A. McKenzie0L. E. Miller1J. S. Slawson2J. S. Slawson3E. J. MacKie4S. Wang5Department of Environmental Sciences, University of Virginia, 291 McCormick Rd., Charlottesville, VA 22904, USADepartment of Environmental Sciences, University of Virginia, 291 McCormick Rd., Charlottesville, VA 22904, USADepartment of Environmental Sciences, University of Virginia, 291 McCormick Rd., Charlottesville, VA 22904, USAcurrently at: Department of Geology and Geological Engineering, Colorado School of Mines, 1516 Illinois St., Golden, CO 80401, USADepartment of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL 32611-2120, USADepartment of Geography, Pennsylvania State University, 302 N Burrowes St., University Park, PA 16802, USA<p>Topographic highs (“bumps”) across glaciated landscapes have the potential to temporarily slow ice sheet flow or, conversely, accelerate ice flow through subglacial strain heating and meltwater production. Isolated bumps of variable size across the deglaciated landscape of the Cordilleran Ice Sheet (CIS) of Washington State present an opportunity to study the influence of topographic highs on ice–bed interactions and ice flow organization. This work utilizes semi-automatic mapping techniques of subglacial bedforms to characterize the morphology of streamlined subglacial bedforms including elongation, surface relief, and orientation, all of which provide insight into subglacial processes during post-Last Glacial Maximum deglaciation. We identify a bump-size threshold of several cubic kilometers – around 4.5 km<span class="inline-formula"><sup>3</sup></span> – in which bumps larger than this size will consistently and significantly disrupt both ice flow organization and subglacial sedimentary processes, which are fundamental to the genesis of streamlined subglacial bedforms. Additionally, sedimentary processes are persistent and well developed downstream of bumps, as reflected by enhanced bedform elongation and reduced surface relief, likely due to increased availability and production of subglacial sediment and meltwater. While isolated topography plays a role in disrupting ice flow, larger bumps have a greater disruption to ice flow organization, while bumps below the identified threshold seem to have little effect on ice and subglacial processes. The variable influence of isolated topographic bumps on ice flow of the CIS has significant implications for outlet glaciers of the Greenland Ice Sheet (GrIS) due to similarities in regional topography, where local bumps are largely unresolved.</p>https://tc.copernicus.org/articles/17/2477/2023/tc-17-2477-2023.pdf |
| spellingShingle | M. A. McKenzie L. E. Miller J. S. Slawson J. S. Slawson E. J. MacKie S. Wang Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes The Cryosphere |
| title | Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes |
| title_full | Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes |
| title_fullStr | Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes |
| title_full_unstemmed | Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes |
| title_short | Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes |
| title_sort | differential impact of isolated topographic bumps on ice sheet flow and subglacial processes |
| url | https://tc.copernicus.org/articles/17/2477/2023/tc-17-2477-2023.pdf |
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