Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet
Understanding drivers of marine-terminating ice sheet behavior is important for constraining ice contributions to global sea-level rise. In part, the stability of marine-terminating ice is influenced by solid-Earth conditions at the grounded-ice margin. While the Cordilleran Ice Sheet (CIS) contribu...
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2023
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Online Access: | http://dx.doi.org/10.22541/essoar.169903694.47074489/v1 |
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crwinnower:10.22541/essoar.169903694.47074489/v1 2024-06-02T07:57:30+00:00 Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet McKenzie, Marion Miller, Lauren E Lepp, Allison DeWitt, Regina 2023 http://dx.doi.org/10.22541/essoar.169903694.47074489/v1 unknown Authorea, Inc. https://creativecommons.org/licenses/by/4.0/ posted-content 2023 crwinnower https://doi.org/10.22541/essoar.169903694.47074489/v1 2024-05-07T14:19:23Z Understanding drivers of marine-terminating ice sheet behavior is important for constraining ice contributions to global sea-level rise. In part, the stability of marine-terminating ice is influenced by solid-Earth conditions at the grounded-ice margin. While the Cordilleran Ice Sheet (CIS) contributed significantly to global mean sea level during its final post-Last Glacial Maximum (LGM) collapse, the drivers and patterns of retreat are not well constrained. Coastal outcrops in the deglaciated Puget Lowland of Washington state - largely below sea level during glacial maxima, then uplifted above sea level via glacial isostatic adjustment (GIA) - record late Pleistocene history of the CIS. The preservation of LGM glacial and post-LGM deglacial sediments provides a unique opportunity to assess variability in marine ice-sheet behavior of the southernmost CIS. Based on paired stratigraphic and geochronological work with a newly developed marine-reservoir correction for this region, we identify that the late-stage CIS experienced stepwise retreat into a marine environment about 12,000 years before present, placing glacial ice in the region for about 3,000 years longer than previously thought. Stand-still of marine-terminating ice for a millenia, paired with rapid vertical landscape evolution, was followed by continued retreat of ice in a subaerial environment. These results suggest rapid rates of solid Earth uplift and topographic support (e.g., grounding-zone wedges) stabilized the ice-margin, supporting final subaerial ice retreat. This work leads to a better understanding of shallow marine and coastal ice sheet retreat; relevant to sectors of the contemporary Antarctic and Greenland ice sheets and marine-terminating outlet glaciers. Other/Unknown Material Antarc* Antarctic Greenland Ice Sheet The Winnower Antarctic Greenland |
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Understanding drivers of marine-terminating ice sheet behavior is important for constraining ice contributions to global sea-level rise. In part, the stability of marine-terminating ice is influenced by solid-Earth conditions at the grounded-ice margin. While the Cordilleran Ice Sheet (CIS) contributed significantly to global mean sea level during its final post-Last Glacial Maximum (LGM) collapse, the drivers and patterns of retreat are not well constrained. Coastal outcrops in the deglaciated Puget Lowland of Washington state - largely below sea level during glacial maxima, then uplifted above sea level via glacial isostatic adjustment (GIA) - record late Pleistocene history of the CIS. The preservation of LGM glacial and post-LGM deglacial sediments provides a unique opportunity to assess variability in marine ice-sheet behavior of the southernmost CIS. Based on paired stratigraphic and geochronological work with a newly developed marine-reservoir correction for this region, we identify that the late-stage CIS experienced stepwise retreat into a marine environment about 12,000 years before present, placing glacial ice in the region for about 3,000 years longer than previously thought. Stand-still of marine-terminating ice for a millenia, paired with rapid vertical landscape evolution, was followed by continued retreat of ice in a subaerial environment. These results suggest rapid rates of solid Earth uplift and topographic support (e.g., grounding-zone wedges) stabilized the ice-margin, supporting final subaerial ice retreat. This work leads to a better understanding of shallow marine and coastal ice sheet retreat; relevant to sectors of the contemporary Antarctic and Greenland ice sheets and marine-terminating outlet glaciers. |
format |
Other/Unknown Material |
author |
McKenzie, Marion Miller, Lauren E Lepp, Allison DeWitt, Regina |
spellingShingle |
McKenzie, Marion Miller, Lauren E Lepp, Allison DeWitt, Regina Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet |
author_facet |
McKenzie, Marion Miller, Lauren E Lepp, Allison DeWitt, Regina |
author_sort |
McKenzie, Marion |
title |
Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet |
title_short |
Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet |
title_full |
Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet |
title_fullStr |
Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet |
title_full_unstemmed |
Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet |
title_sort |
evidence of solid earth influence on stability of the marine-terminating puget lobe of the cordilleran ice sheet |
publisher |
Authorea, Inc. |
publishDate |
2023 |
url |
http://dx.doi.org/10.22541/essoar.169903694.47074489/v1 |
geographic |
Antarctic Greenland |
geographic_facet |
Antarctic Greenland |
genre |
Antarc* Antarctic Greenland Ice Sheet |
genre_facet |
Antarc* Antarctic Greenland Ice Sheet |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.22541/essoar.169903694.47074489/v1 |
_version_ |
1800740650496294912 |