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TitleRapid seafloor changes associated with the degradation of Arctic submarine permafrost
AuthorPaull, C; Dallimore, S RORCID logo; Jin, Y; Carress, D; Lumsden, E; Anderson, C; Gwiazada, R; Youngblut, S; Hughes Clarke, J; Melling, H
SourceProceedings of the National Academy of Sciences of the United States of America vol. 119, no. 12, 2022 p. 1-8, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20210646
Mediapaper; on-line; digital
File formatpdf
NTS107; 117
Lat/Long WENS-132.0000 -128.0000 72.0000 68.0000
Subjectsmarine geology; permafrost; arctic geology; mapping techniques; pingos; thermokarst
Illustrationslocation maps; cross-sections; bathymetric profiles; images; plots
ProgramPublic Safety Geoscience Beaufort Sea Exploration
ProgramClimate Change Geoscience Permafrost
Released2022 03 14
AbstractRepeated high-resolution bathymetric surveys of the shelf edge of the Canadian Beaufort Sea during 2- to 9-y-long survey intervals reveal rapid morphological changes. New steep-sided depressions up to 28 m in depth developed, and lateral retreat along scarp faces occurred at multiple sites. These morphological changes appeared between 120-m and 150-m water depth, near the maximum limit of the submerged glacial-age permafrost, and are attributed to permafrost thawing where ascending groundwater is concentrated along the relict permafrost boundary. The groundwater is produced by the regional thawing of the permafrost base due to the shift in the geothermal gradient as a result of the interglacial transgression of the shelf. In contrast, where groundwater discharge is reduced, sediments freeze at the ambient sea bottom temperature of -1.4 °C. The consequent expansion of freezing sediment creates ice-cored topographic highs or pingos, which are particularly abundant adjacent to the discharge area.
Summary(Plain Language Summary, not published)
This paper describes sea floor processes at the transition between the outer Beaufort Sea shelf and the upper slope. Repeat bathymetric surveys reveal that in this area large craters or depressions up to 18m deep and >100m in extent are actively forming as a result of thawing of deep permafrost. In addition a concentrated occurrence of sea floor pingos or small mounds are also described which have formed from permafrost formation in the near surface. The study has implications for assessment of sea floor geohazards in this setting as well as environmental processes.

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