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TitleAssessment of physicochemical properties in lentic surface water bodies of the Rankin Inlet area (Nunavut) for sublacustrine open talik detection
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorFaucher, BORCID logo; LeBlanc, A -MORCID logo; Utting, NORCID logo; Blade, M
SourceGeological Survey of Canada, Open File 8898, 2022, 33 pages, Open Access logo Open Access
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf
NTS55J/13; 55K/14; 55K/15; 55K/16; 55N/01; 55N/02; 55N/03; 55O/04
AreaRankin Inlet; Kivalliq
Lat/Long WENS -93.0833 -91.7500 63.2500 62.7500
Subjectshydrogeology; environmental geology; geochemistry; surficial geology/geomorphology; regional geology; Nature and Environment; Science and Technology; Economics and Industry; permafrost; ground ice; periglacial features; talik; surface waters; lakes; water levels; water quality; groundwater; groundwater regimes; groundwater pollution; mining; thermal analyses; geochemical analyses; models; lake water geochemistry; statistical analyses; bedrock geology; lithology; evaporation; till geochemistry; geological history; climate; Archean; Canadian Shield; Churchill Province; Rankin Inlet Greenstone Belt; Laurentide Ice Sheet; Wisconsin Glaciation; Tyrrell Sea; Meliadine Mine; Methodology; Mining industry; Hydrology; Phanerozoic; Cenozoic; Quaternary; Precambrian
Illustrationstables; location maps; geoscientific sketch maps; time series; plots; ternary diagrams; schematic representations; bar graphs; models
ProgramGEM-GeoNorth: Geo-mapping for Energy and Minerals GEM Program Coordination
Released2022 06 21
In periglacial landscapes of Northern Canada, the presence of open taliks (layer of unfrozen ground that penetrates permafrost completely) beneath lakes can connect surface waters to subpermafrost groundwater. With increasing mining activity in northern Canada, it is critical for mining projects to identify lakes potentially underlain by open taliks and their subpermafrost groundwater-surface water connectivity to assess effects on mining operations and lake water levels, lake water quality, and regional groundwater systems. The presence of sublacustrine open taliks can be assessed with thermal models, but validating their presence remains challenging at a regional scale due to the difficulty and cost of acquiring field data at this scale. The level of hydrological connectivity between the lakes and subpermafrost groundwater systems also remains largely unknown. This work explores the physical attributes and water chemistry of lakes in the Rankin Inlet area (NU) to infer the presence of open talik and to quantify connectivity between lakes and groundwater. In particular, we evaluate if significant differences exist in the chemical composition of those water basins and if associated findings can shed light on the local surface and groundwater connectivity. We reach this goal by exploring the water quality of lakes (n=41) of archived datasets obtained from Environmental Impact Assessments (EIA) reports, and Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) and Kivalliq Inuit Association (KIA) annual field sampling reports. We demonstrate through statistical analyses that significant differences exist between the chemical composition of open taliks lakes and those with no taliks; although those differences are likely not entirely due to surface-groundwater interactions. Results also suggest that rock-water interactions can explain the chemical composition of waters in most of the lakes, but that some no open talik lakes are seemingly also affected by evaporation. We employ geochemical models to initially predict the chemical composition of open talik lakes once atmospherically equilibrated snow meltwaters have weathered local surficial deposits (i.e., till) and have subsequently mixed with hypersaline subpermafrost waters. A geochemical model is also utilized to model the predicted chemical evolution of no open talik lakes affected by evaporation. Our study reveals that we are lacking sufficient empirical data to properly predict which lakes have sublacustrine taliks below them and which do not. We conclude by proposing a list of additional measurements, data, and laboratory analyses that should be considered to better assess potential surface-groundwater interactions in the Rankin Inlet area.
Summary(Plain Language Summary, not published)
At high latitudes, perennially frozen ground (i.e., permafrost) acts as a barrier for surface-groundwater interactions. However, unfrozen ground (i.e., open talik) where such exchanges may take place is often found below large lakes. Constructing mining facilities near those basins may cause significant problems (e.g., water infiltration within a mine; adverse effects on surficial waters): locating those is crucial for the management of safe and durable mining operations. Traditionally, open talik below lakes are detected using lacustrine morphometric and thermal properties, and few have tried to use lacustrine chemical properties to assess the occurrence of open taliks. We used the latter approach for lakes and ponds situated in the Rankin Inlet area. We found significant differences for the chemical composition of suspected open vs. no open talik basins. Yet, those differences are not imputable to influxes of groundwaters towards surficial water basins; land surface processes (i.e., weathering and evaporation) cause them. Hence, our study reveals that basic limnological properties cannot solely be used to detect open taliks in this area region.

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