Preprints
https://doi.org/10.22541/essoar.169903694.47074489/v1
https://doi.org/10.22541/essoar.169903694.47074489/v1
17 Nov 2023
 | 17 Nov 2023

Evidence of solid Earth influence on stability of the marine-terminating Puget Lobe of the Cordilleran Ice Sheet

Marion McKenzie, Lauren E. Miller, Allison Lepp, and Regina DeWitt

Abstract. 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.

Share

Journal article(s) based on this preprint

10 Apr 2024
Spatial variability of marine-terminating ice sheet retreat in the Puget Lowland
Marion A. McKenzie, Lauren E. Miller, Allison P. Lepp, and Regina DeWitt
Clim. Past, 20, 891–908, https://doi.org/10.5194/cp-20-891-2024,https://doi.org/10.5194/cp-20-891-2024, 2024
Short summary
Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
Glaciers that deposit ice directly into the ocean are capable of contributing to global sea...
Share