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Abstract Permafrost warming and degradation is well documented across the Arctic. However, observation‐ and model‐based studies typically consider thaw to occur at 0°C, neglecting the widespread occurrence of saline permafrost in coastal plain regions. In this study, we document rapid saline permafrost thaw below a shallow arctic lake. Over the 15‐year period, the lakebed subsided by 0.6 m as ice‐rich, saline permafrost thawed. Repeat transient electromagnetic measurements show that near‐surface bulk sediment electrical conductivity increased by 198% between 2016 and 2022. Analysis of wintertime Synthetic Aperture Radar satellite imagery indicates a transition from a bedfast to a floating ice lake with brackish water due to saline permafrost thaw. The regime shift likely contributed to the 65% increase in thermokarst lake lateral expansion rates. Our results indicate that thawing saline permafrost may be contributing to an increase in landscape change rates in the Arctic faster than anticipated.
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This content will become publicly available on May 16, 2026
Postglacial canyon incision primes ice-cored hillslopes for thaw slumping in the western Canadian Arctic
Abstract Thaw-induced permafrost landslides, or thaw slumps, exemplify the alarming potential of rapid Arctic climate change to couple with unstable geomorphic feedbacks and escalate landscape hazards, sediment and solute fluxes, and carbon emissions. An emergent hot spot of thaw slump activity in the western Canadian Arctic provides an opportunity to understand the geomorphic context that predisposes some regions to extreme thaw sensitivity. Previous research suggests that slump concentration in this region may result from postglacial incision of ice-cored moraine along the historical margin of the Laurentide Ice Sheet. We assess this hypothesis in the Aklavik Range of the Northwest Territories, where we mapped 217 thaw slumps and reconstructed more than 3 m/k.y. of bedrock canyon incision since the Last Glacial Maximum. We find that thaw slumps tend to form between fluvially incised bedrock and relict till hillslopes. More than 75% of thaw slumping occurs within 500 m of incised bedrock, and hillslope normalized steepness explains over 33% of slump size variability. We interpret intense regional thaw slumping as a climate-sensitive landscape response to postglacial base-level change propagating into ice-cored hillslopes. This finding implies that the end-member permafrost disturbances observed in the western Canadian Arctic may be limited outside regions that share analogous geomorphic context.
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- Award ID(s):
- 2116471
- PAR ID:
- 10657876
- Publisher / Repository:
- The data and code for this study are archived at the NSF Arctic Data Center, https://doi .org /10 .18739 /A2KP7TT34.
- Date Published:
- Journal Name:
- Geology
- Volume:
- 53
- Issue:
- 8
- ISSN:
- 0091-7613
- Page Range / eLocation ID:
- 657 to 662
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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