Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet
Abstract Both modern and palaeo‐ice streams experience shutdown, which has critical implications for their mass balance and influence on relative sea level. Reconstructions of palaeo‐ice streams have mainly focused on their phase of active flow and thus less is understood of their shutdown and style...
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crwiley:10.1002/esp.5636 2024-09-15T18:12:17+00:00 Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet Aradóttir, Nína Benediktsson, Ívar Örn Ingólfsson, Ólafur Brynjólfsson, Skafti Farnsworth, Wesley R. Benjamínsdóttir, Margrét Mjöll Ríkharðsdóttir, Lena Björg 2023 http://dx.doi.org/10.1002/esp.5636 https://onlinelibrary.wiley.com/doi/pdf/10.1002/esp.5636 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Earth Surface Processes and Landforms volume 48, issue 12, page 2412-2430 ISSN 0197-9337 1096-9837 journal-article 2023 crwiley https://doi.org/10.1002/esp.5636 2024-07-04T04:31:28Z Abstract Both modern and palaeo‐ice streams experience shutdown, which has critical implications for their mass balance and influence on relative sea level. Reconstructions of palaeo‐ice streams have mainly focused on their phase of active flow and thus less is understood of their shutdown and style of deglaciation. Mapping of streamlined subglacial bedforms (SSBs), including drumlins and mega‐scale glacial lineations, in northeast Iceland reveals cross‐cutting flow‐sets of palaeo‐ice streams within the Iceland Ice Sheet (IIS) during and following the last glacial maximum (LGM). Here we map geometrical ridges (linear and reticular) within the Bakkaflói and Þistilfjörður flow‐sets and combine the morphological data with sedimentological analyses to increase our understanding of the dynamics of the IIS during deglaciation in northeast Iceland. We interpret the ridges as crevasse‐squeeze ridges (CSRs), based on their interconnected network, primary orientation transverse and/or oblique to former ice flow and internal composition of homogenous subglacial till. In both areas, the CSRs are superimposed on the SSBs, indicating that they post‐date the SSBs and signify the waning stage of ice streaming associated with the readvance of the IIS during the Younger Dryas period. The preservation of the CSRs suggests ice stagnation following the readvance and ice‐stream shutdown. The morphological difference of the CSRs between the flow‐sets is taken to indicate different kinematic setting within the ice streams; the linear CSRs in Bakkaflói formed further upstream where extensional forces parallel to ice flow were dominant, whereas the reticular CSRs in Þistilfjörður are more indicative of transverse and longitudinal forces near the terminal zone. Future research reconstructing past ice‐sheet behaviour and ice‐stream dynamics would benefit from high‐resolution bathymetric data from the adjoining shelf as well as enhanced geochronological constraints. Article in Journal/Newspaper Ice Sheet Iceland Wiley Online Library Earth Surface Processes and Landforms 48 12 2412 2430 |
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Open Polar |
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Wiley Online Library |
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crwiley |
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English |
description |
Abstract Both modern and palaeo‐ice streams experience shutdown, which has critical implications for their mass balance and influence on relative sea level. Reconstructions of palaeo‐ice streams have mainly focused on their phase of active flow and thus less is understood of their shutdown and style of deglaciation. Mapping of streamlined subglacial bedforms (SSBs), including drumlins and mega‐scale glacial lineations, in northeast Iceland reveals cross‐cutting flow‐sets of palaeo‐ice streams within the Iceland Ice Sheet (IIS) during and following the last glacial maximum (LGM). Here we map geometrical ridges (linear and reticular) within the Bakkaflói and Þistilfjörður flow‐sets and combine the morphological data with sedimentological analyses to increase our understanding of the dynamics of the IIS during deglaciation in northeast Iceland. We interpret the ridges as crevasse‐squeeze ridges (CSRs), based on their interconnected network, primary orientation transverse and/or oblique to former ice flow and internal composition of homogenous subglacial till. In both areas, the CSRs are superimposed on the SSBs, indicating that they post‐date the SSBs and signify the waning stage of ice streaming associated with the readvance of the IIS during the Younger Dryas period. The preservation of the CSRs suggests ice stagnation following the readvance and ice‐stream shutdown. The morphological difference of the CSRs between the flow‐sets is taken to indicate different kinematic setting within the ice streams; the linear CSRs in Bakkaflói formed further upstream where extensional forces parallel to ice flow were dominant, whereas the reticular CSRs in Þistilfjörður are more indicative of transverse and longitudinal forces near the terminal zone. Future research reconstructing past ice‐sheet behaviour and ice‐stream dynamics would benefit from high‐resolution bathymetric data from the adjoining shelf as well as enhanced geochronological constraints. |
format |
Article in Journal/Newspaper |
author |
Aradóttir, Nína Benediktsson, Ívar Örn Ingólfsson, Ólafur Brynjólfsson, Skafti Farnsworth, Wesley R. Benjamínsdóttir, Margrét Mjöll Ríkharðsdóttir, Lena Björg |
spellingShingle |
Aradóttir, Nína Benediktsson, Ívar Örn Ingólfsson, Ólafur Brynjólfsson, Skafti Farnsworth, Wesley R. Benjamínsdóttir, Margrét Mjöll Ríkharðsdóttir, Lena Björg Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet |
author_facet |
Aradóttir, Nína Benediktsson, Ívar Örn Ingólfsson, Ólafur Brynjólfsson, Skafti Farnsworth, Wesley R. Benjamínsdóttir, Margrét Mjöll Ríkharðsdóttir, Lena Björg |
author_sort |
Aradóttir, Nína |
title |
Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet |
title_short |
Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet |
title_full |
Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet |
title_fullStr |
Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet |
title_full_unstemmed |
Ice‐stream shutdown during deglaciation: Evidence from crevasse‐squeeze ridges of the Iceland Ice Sheet |
title_sort |
ice‐stream shutdown during deglaciation: evidence from crevasse‐squeeze ridges of the iceland ice sheet |
publisher |
Wiley |
publishDate |
2023 |
url |
http://dx.doi.org/10.1002/esp.5636 https://onlinelibrary.wiley.com/doi/pdf/10.1002/esp.5636 |
genre |
Ice Sheet Iceland |
genre_facet |
Ice Sheet Iceland |
op_source |
Earth Surface Processes and Landforms volume 48, issue 12, page 2412-2430 ISSN 0197-9337 1096-9837 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/esp.5636 |
container_title |
Earth Surface Processes and Landforms |
container_volume |
48 |
container_issue |
12 |
container_start_page |
2412 |
op_container_end_page |
2430 |
_version_ |
1810449868514131968 |