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TitleNew ground ice maps for Canada using a paleogeographic modelling approach
AuthorO'Neill, H B; Wolfe, S A; Duchesne, C
SourceThe Cryosphere vol. 13, issue 3, 2019 p. 753-773, https://doi.org/10.5194/tc-13-753-2019 (Open Access)
Year2019
Alt SeriesNatural Resources Canada, Contribution Series 20180186
PublisherCopernicus GmbH
Documentserial
Lang.English
Mediaon-line; digital
File formatpdf; html
ProvinceCanada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Subjectsenvironmental geology; surficial geology/geomorphology; permafrost; ground ice; periglacial features; ice wedges; paleogeography; modelling; climate; mapping techniques; glacial history; deglaciation; paleoclimates; postglacial emergence; glacial deposits; marine sediments; silts; clays; sands; gravels; colluvial deposits; felsenmeer; slumps; massive ice; climate change; permafrost degradation; relict ice; segregated ice; wedge ice; expert systems; geographic information system applications; paleovegetation; limit of submergence, glaciolacustrine; limit of submergence, glaciomarine; tree line migration; glaciolacustrine sediments; glaciomarine sediments; tundra; thaw slumps; alluvial sediments; blocks; rubble; weathered bedrock or regolith veneer; Phanerozoic; Cenozoic; Quaternary
Illustrationsgeoscientific sketch maps; tables
ProgramPermafrost, Climate Change Geoscience
Released2019 03 05
AbstractGround ice melt caused by climate-induced permafrost degradation may trigger significant ecological change, damage infrastructure, and alter biogeochemical cycles. The fundamental ground ice mapping for Canada is now > 20 years old and does not include significant new insights gained from recent field- and remote-sensing-based studies. New modelling incorporating paleogeography is presented in this paper to depict the distribution of three ground ice types (relict ice, segregated ice, and wedge ice) in northern Canada. The modelling uses an expert-system approach in a geographic information system (GIS), founded in conceptual principles gained from empirically based research, to predict ground ice abundance in near-surface permafrost. Datasets of surficial geology, deglaciation, paleovegetation, glacial lake and marine limits, and modern permafrost distribution allow representations in the models of paleoclimatic shifts, tree line migration, marine and glacial lake inundation, and terrestrial emergence, and their effect on ground ice abundance. The model outputs are generally consistent with field observations, indicating abundant relict ice in the western Arctic, where it has remained preserved since deglaciation in thick glacigenic sediments in continuous permafrost. Segregated ice is widely distributed in fine-grained deposits, occurring in the highest abundance in glacial lake and marine sediments. The modelled abundance of wedge ice largely reflects the exposure time of terrain to low air temperatures in tundra environments following deglaciation or marine/glacial lake inundation and is thus highest in the western Arctic. Holocene environmental changes result in reduced ice abundance where the tree line advanced during warmer periods. Published observations of thaw slumps and massive ice exposures, segregated ice and associated landforms, and ice wedges allow a favourable preliminary assessment of the models, and the results are generally comparable with the previous ground ice mapping for Canada. However, the model outputs are more spatially explicit and better reflect observed ground ice conditions in many regions. Synthetic modelling products that incorporated the previous ground ice information may therefore include inaccuracies. The presented modelling approach is a significant advance in permafrost mapping, but additional field observations and volumetric ice estimates from more areas in Canada are required to improve calibration and validation of small-scale ground ice modelling. The ground ice maps from this paper are available in the supplement in GeoTIFF format.
Summary(Plain Language Summary, not published)
New models depict ground ice in permafrost in Canada. The models use a new approach to calculate ground ice abundance in a geographic information system. Datasets of surficial geology, deglaciation, paleovegetation, glacial lake and marine limits, and modern permafrost distribution represent past environmental changes. Abundant massive ice is modelled in the western Arctic, preserved since deglaciation in continuous permafrost. Segregated ice is distributed in fine-grained soils, occurring in highest abundance in glacial lake and marine sediments. The modelled abundance of wedge ice reflects the exposure time of terrain to cold air temperatures following deglaciation, and is highest in the western Arctic. The model outputs reproduce observed regional ground ice conditions and are generally comparable with previous mapping. However, the new models are more detailed and better reflect observed ground ice conditions.
GEOSCAN ID311180