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TitreLake shoreline evolution and permafrost-related drivers, Rankin Inlet, Nunavut
AuteurLeBlanc, A -M; Bellehumeur-Génier, O; Oldenborger, G; Short, N
SourceArcticNet 2018 Annual Scientific Meeting, proceedings/ArcticNet 2018 Réunion scientifique annuelle, proceedings; 2018 p. 114 (Accès ouvert)
LiensOnline - En ligne (complete volume - volume complet, PDF, 2.35 MB)
Année2018
Séries alt.Ressources naturelles Canada, Contribution externe 20190208
ÉditeurArcticNet
RéunionASM2018 - ArcticNet 2018 Annual Scientific Meeting; Ottawa, ON; CA; décembre 10-14, 2018
Documentlivre
Lang.anglais
Mediaen ligne; numérique
Formatspdf
ProvinceNunavut
SNRC55K/16
RégionKivalliq; Rankin Inlet; Baie d'Hudson
Lat/Long OENS -92.3508 -92.1539 62.9206 62.8761
Sujetspergélisol; glace fossile; caractéristiques périglaciaires; fentes de glace; eaux de surface; lacs; variations du littoral; niveaux d'eau; effets climatiques; télédétection; imagerie par satellite; interprétation de photos aériennes; milieu hydrologique; neige; précipitation; dépôts glaciaires; tills; sédiments marins; topographie; déplacement; changement climatique; dégel du pergélisol; infrastructure; culture autochtone; terres autochtones; sédiments fluvioglaciaires; hydrogéologie; géologie des dépôts meubles/géomorphologie; géologie de l'environnement; géophysique; Nature et environnement; Sciences et technologie
ProgrammeGéosciences de changements climatiques, Pergélisols
Diffusé2018 12 01
Résumé(disponible en anglais seulement)
The western coast of Hudson Bay in the Kivalliq Region of Nunavut is rich in natural resources and has potential for resource development. In addition, the establishment of a transportation and transmission corridor between Manitoba and the Kivalliq region has been under consideration for several years. Knowledge of permafrost conditions and processes is required to understand climate change impacts and to aid in developing adaptation solutions. However, the scarcity of permafrost data along the western coast of Hudson Bay hinders understanding of historical and contemporary permafrost conditions and sensitivity to climate warming. Local and traditional knowledge on permafrost and landscape change was gathered at a participatory mapping workshop in Rankin Inlet in 2016 to improve regional characterization of permafrost conditions. Among various observations, the most recurrent was of decreasing lake water levels. Analysis of historical air photos and satellite imagery was completed for 215 lakes near Rankin Inlet, and validated by field observations. The objective was to determine if permafrost-related drivers could explain the observed lake level changes after accounting for fluctuations in lake area caused by variations in the hydrological cycle, inferred by historical snow and precipitation conditions. Analysis results indicated that lakes in the study area were either expanding, draining, or remaining stable. Draining lakes were easier to identify than expanding lakes, which were only perceptible by subtle local changes in shoreline morphology. This might explain why local knowledge holders have preferentially reported low lake water levels in recent years. The distribution of lake expansion and drainage was influenced by surficial geology. A disproportionately high number of observations of lake expansion occurred in undifferentiated till and marine sediments. Draining lakes were more commonly found in glaciofluvial sediments, especially in areas of high topographic relief. Seasonal and inter-annual ground surface displacement measured with Radarsat-2 and ALOS-2, respectively, were used to validate areas of change near lake shorelines. Though translation of these remotely-sensed datasets to real displacement measurements is not straightforward, general relations were nonetheless established between the displacements and locations of stable, expanding, and draining lakes. These relations support (1) the thaw of ice-rich layers near the top of permafrost where localised lake expansion is observed, and (2) increased lake storage resulting from active layer thickening in coarse sediments. We also hypothesize that ice-wedge degradation is involved in lake water level changes. The results of this study contribute to a better understanding of the relation between permafrost and surficial geology, and how these terrain units could respond to a warming climate.
Sommaire(Résumé en langage clair et simple, non publié)
La Commission géologique du Canada a entrepris une étude pour déterminer si le dégel du pergélisol pourrait expliquer une observation, faite par la population locale, sur le changement de niveau d'eau de lacs près de la localité de Rankin Inlet, au Nunavut. La connaissance des conditions du pergélisol est nécessaire pour comprendre les impacts des changements climatiques et pour appuyer le développement de solutions d'adaptation. Les résultats ont indiqué que certains des changements de niveau d'eau résultaient du dégel du pergélisol, induit par les changements climatiques, tandis que d'autre répondaient aux changements de précipitations annuelles. Quand le dégel du pergélisol était impliqué, les changements de niveau d'eau des lacs étaient influencés par la géologie de surface. Cette association entre le changement du niveau d'eau des lacs, le dégel du pergélisol et les dépôts de surface est utilisée pour extrapoler les conditions du pergélisol à échelle régionale et ainsi évaluer comment les unités de terrain pourraient répondre au réchauffement du climat.
GEOSCAN ID315668