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TitleLake area and shoreline changes due to climate and permafrost-related drivers, Rankin Inlet area, Nunavut
AuthorLeBlanc, A -M; Bellehumeur-Génier, O; Oldenborger, G A; Short, N
SourceCanada-Nunavut Geoscience Office, Summary of Activities 2019, 2020 p. 79-92 (Open Access)
LinksOnline - En ligne
Alt SeriesNatural Resources Canada, Contribution Series 20190351
PublisherCanada-Nunavut Geoscience Office
Mediapaper; on-line; digital
File formatpdf
AreaRankin Inlet; Hudson Bay; Kivalliq Region
Lat/Long WENS -92.3508 -92.1539 62.9206 62.8761
Subjectshydrogeology; surficial geology/geomorphology; environmental geology; geophysics; Nature and Environment; Science and Technology; surface waters; lakes; shoreline changes; climatology; climate effects; precipitation; temperature; permafrost; ground ice; periglacial features; thermokarst; ice wedges; displacement; subsidence; remote sensing; photogrammetric techniques; airphoto interpretation; satellite imagery; field work; groundwater; floods; drainage; sediments; marine sediments; glacial deposits; ice contact deposits; tills; climate change; permafrost thaw; infrastructures; lake surface area; lake levels; active layer thickness; groundwater storage; alluvial sediments; marine beach sediments; marine nearshore sediments; glaciofluvial subaqueous outwash fan sediments; glaciofluvial hummocky sediments; glaciofluvial sediments; hummocky tills; ridged tills, moraine; till veneer; till blanket; areas of interest; differential interferometric synthetic aperture radar (DInSAR); thaw ponds; economic impact
Illustrationsgeoscientific sketch maps; time series; tables; location maps; bar graphs; satellite images; aerial photographs; photographs
ProgramClimate Change Geoscience, Coastal Infrastructure
Released2020 03 01
AbstractThe western coast of Hudson Bay is experiencing growth for which information on permafrost is required to ensure resilience of infrastructure in the context of climate warming. Using airphotos and satellite imagery from 1954 to 2017, climate data, surficial geology, field observations and ground-displacement data derived from remote sensing, the potential for climate and permafrost-related drivers are examined to explain the observed changes in lake area near the Hamlet of Rankin Inlet, Nunavut. Although there is some evidence that climate variables, such as precipitation, explain some variation in lake-water level, it appears that the response of permafrost to the warming climate since 1993 is a significant factor in modern shoreline changes. Lake expansion attributed to thermokarst processes was observed in fine-grained and ice-rich sediments. The permafrost thaw was likely induced by frequent inundation and was typically accompanied by significant localized shoreline disturbance that remained present even in dry years. In contrast, in coarse-grained and ice-poor sediments, thickening of the active layer likely causes the subsurface water storage to increase, contributing to lake drainage. Normal and wet years are now insufficient to refill lakes to their historical maximum, particularly in areas of high topographic relief. Visual assessment of shoreline morphologies provides amore robust indicator of lake instability than the extent of lake-area change alone. The link between surficial geology and lake instability provides useful insight into changes in near-surface permafrost conditions in the area of Rankin Inlet.
Summary(Plain Language Summary, not published)
The Kivalliq region of Nunavut is undergoing significant infrastructure development for which permafrost information is required. Landscape changes, such as change in lakes water level, can revealed important information on permafrost conditions and its sensitivity to climate change. The study described here investigates the role of permafrost-related drivers to explain the observed changes in lake area near the Hamlet of Rankin Inlet, Nunavut. Methods used include air photos and satellite imagery, climate data, surficial geology, field observations and ground displacements derived from remote sensing. The results indicate that climatic variables, such as precipitation, are important factors, but that permafrost degradation, either by subsidence of ice-rich soil or thickening of the unfrozen layer above permafrost, also plays an important role for some lakes leading to their expansion or drainage. There is also a link between surface geology and the expansion or drainage of lakes. Therefore, this link provides useful insight into the change in near-surface permafrost conditions.