The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost
Thermo-erosion gullies (TEGs) are one of the most common forms of abrupt permafrost degradation. They generally form in ice-wedge polygonal networks where the interconnected troughs can channel runoff water. Although TEG can form within a single thawing season, it takes them several decades for thei...
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ftcopernicus:oai:publications.copernicus.org:egusphere117710 2024-09-15T17:34:52+00:00 The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost Gagnon, Samuel Fortier, Daniel Godin, Etienne Veillette, Audrey 2024-03-14 application/pdf https://doi.org/10.5194/egusphere-2024-208 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-208/ eng eng doi:10.5194/egusphere-2024-208 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-208/ eISSN: Text 2024 ftcopernicus https://doi.org/10.5194/egusphere-2024-208 2024-08-28T05:24:15Z Thermo-erosion gullies (TEGs) are one of the most common forms of abrupt permafrost degradation. They generally form in ice-wedge polygonal networks where the interconnected troughs can channel runoff water. Although TEG can form within a single thawing season, it takes them several decades for their complete stabilization. While the inception of TEGs has been examined in several studies, the processes of their stabilization remain poorly documented, especially the ground ice patterns that form following permafrost aggradation in stabilizing TEGs. For this study, we investigated the impacts of two TEGs in the Canadian High Arctic (Bylot Island, NU, Canada) on ground ice content, cryostratigraphic patterns, and geomorphology to examine permafrost recovery following thermal erosion in ice-wedge polygonal tundra. We sampled 17 permafrost cores from two TEGs – one still active (since 1999) and one stabilized (>100 years old) – to describe the surface conditions, interpret the cryostratigraphic patterns, and characterize the state of permafrost after TEG stabilization. We observed that although the TEG caused discernable cryostratigraphic patterns, ground ice content and active layer thickness of the TEGs were comparable to measurements made in undisturbed conditions. We also noted that once stabilized, TEGs permanently (at the Anthropocene scale) alter landscape morphology and hydrological connectivity. We concluded that although the formation of a TEG has profound effects on the short/medium term and leaves near permanent geomorphological and hydrological scars in periglacial landscapes, on the long term, High Arctic permafrost can recover and return to geocryological conditions similar to those pre-dating the initial disturbance. This suggests that in stable environmental conditions undergoing natural variability, permafrost can persist longer than the geomorphological landforms in which it forms. Text Active layer thickness Bylot Island Ice permafrost Tundra wedge* Copernicus Publications: E-Journals |
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English |
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Thermo-erosion gullies (TEGs) are one of the most common forms of abrupt permafrost degradation. They generally form in ice-wedge polygonal networks where the interconnected troughs can channel runoff water. Although TEG can form within a single thawing season, it takes them several decades for their complete stabilization. While the inception of TEGs has been examined in several studies, the processes of their stabilization remain poorly documented, especially the ground ice patterns that form following permafrost aggradation in stabilizing TEGs. For this study, we investigated the impacts of two TEGs in the Canadian High Arctic (Bylot Island, NU, Canada) on ground ice content, cryostratigraphic patterns, and geomorphology to examine permafrost recovery following thermal erosion in ice-wedge polygonal tundra. We sampled 17 permafrost cores from two TEGs – one still active (since 1999) and one stabilized (>100 years old) – to describe the surface conditions, interpret the cryostratigraphic patterns, and characterize the state of permafrost after TEG stabilization. We observed that although the TEG caused discernable cryostratigraphic patterns, ground ice content and active layer thickness of the TEGs were comparable to measurements made in undisturbed conditions. We also noted that once stabilized, TEGs permanently (at the Anthropocene scale) alter landscape morphology and hydrological connectivity. We concluded that although the formation of a TEG has profound effects on the short/medium term and leaves near permanent geomorphological and hydrological scars in periglacial landscapes, on the long term, High Arctic permafrost can recover and return to geocryological conditions similar to those pre-dating the initial disturbance. This suggests that in stable environmental conditions undergoing natural variability, permafrost can persist longer than the geomorphological landforms in which it forms. |
format |
Text |
author |
Gagnon, Samuel Fortier, Daniel Godin, Etienne Veillette, Audrey |
spellingShingle |
Gagnon, Samuel Fortier, Daniel Godin, Etienne Veillette, Audrey The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost |
author_facet |
Gagnon, Samuel Fortier, Daniel Godin, Etienne Veillette, Audrey |
author_sort |
Gagnon, Samuel |
title |
The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost |
title_short |
The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost |
title_full |
The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost |
title_fullStr |
The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost |
title_full_unstemmed |
The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost |
title_sort |
cryostratigraphy of thermo-erosion gullies in the canadian high arctic demonstrates the resilience of permafrost |
publishDate |
2024 |
url |
https://doi.org/10.5194/egusphere-2024-208 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-208/ |
genre |
Active layer thickness Bylot Island Ice permafrost Tundra wedge* |
genre_facet |
Active layer thickness Bylot Island Ice permafrost Tundra wedge* |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2024-208 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-208/ |
op_doi |
https://doi.org/10.5194/egusphere-2024-208 |
_version_ |
1810431453528326144 |