New ground ice maps for Canada using a paleogeographic modelling approach

O'Neill, H B; Wolfe, S A; Duchesne, C

doi:10.5194/tc-13-753-2019

Cited by 73 publications

(73 citation statements)

References 128 publications

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“…Excess-ice contents of 20-60 % are common, especially in till and till-derived sediments, and the average field logged visible-ice content is 24 %. This new regional insight improves upon coarse-scale compilations that rate the area north of Lac de Gras as ice poor (O'Neill et al, 2019;Brown et al, 1997;Heginbottom et al, 1995).…”

mentioning

confidence: 54%

Ground ice, organic carbon and soluble cations in tundra permafrost and active-layer soils near a Laurentide ice divide in the Slave Geological Province, N.W.T., Canada

Subedi

Kokelj

Gruber

2020

Preprint

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Abstract. The central Slave Geological Province is situated near a divide of the Laurentide Ice Sheet and it differs from the western Canadian Arctic, where thaw-induced landscape changes in Laurentide ice-marginal environments are already abundant. Although much of the terrain in the central Slave Geological Province is mapped as predominantly bedrock and ice-poor, glacial deposits of varying thickness occupy significant portions of the landscape, creating a mosaic of conditions. Some evidence of ice-rich ground, a key determinant of thaw-induced landscape change, exists. Carbon and soluble cation content in permafrost are largely unknown in the area. Twenty-four boreholes with depths up to ten metres were drilled in tundra north of Lac de Gras to address these regional gaps in knowledge and to better inform projections and generalizations at coarser scale. Excess-ice contents of 20–60 %, likely remnant Laurentide basal ice, are common in till and thaw subsidence of metres to more than ten metres is possible. Beneath organic terrain and in fluvially-reworked sediment, aggradational ice is found. The abundant ground-ice poses long-term challenges for engineering, and it makes the area susceptible to thaw-induced landscape change and mobilization of sediment, solutes and carbon several metres deep. The characteristics of landscape changes, however, are expected to differ from ice-marginal landscapes of western Arctic Canada, for example, based on subsurface properties. Average soil organic-carbon storage is approximately 8 and 14 kg C m−2 for the depth ranges 0–1 m and 0–3 m. The concentration of total soluble cations in mineral soils is much lower than at other previously studied locations in the western Canadian Arctic. Permafrost in the study area contains much more ground ice than expected, and slightly less organic carbon and fewer soluble cations than well studied areas in the western Canadian Arctic. As these differences are strongly related to geology and glacial history, this study may inform investigations in other parts of the Slave Geological Province and its data can support scenario simulations of future trajectories of permafrost thaw at continental and circumpolar scales.

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confidence: 54%

Ground ice, organic carbon and soluble cations in tundra permafrost and active-layer soils near a Laurentide ice divide in the Slave Geological Province, N.W.T., Canada

Subedi

Kokelj

Gruber

2020

Preprint

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“…The authors apply national-scale modelling results to local site conditions. The authors state that "the new Ground Ice Maps for Canada (O'Neill et al, 2019) show the study area (50 km × 50 km) to contain no or negligible wedge ice, negligible to low segregated ice and no relict ice, which includes buried glacier ice." (lines 40-42).…”

Section: Use Of Model Outputsmentioning

confidence: 99%

“…In fact, the new Ground Ice Maps for Canada depict wedge ice from none to low; segregated ice from none to medium, and relict ice (which includes buried glacier ice) from none to low ( Figure 1). The authors thereby under-report the amount of ground ice depicted for the study areas by O'Neill et al (2019).…”

Section: Use Of Model Outputsmentioning

confidence: 99%

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Subedi et al. (tc-2020-33) Comments

2020

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“…We also summarize the climate and environment information of the study sites, such as mean annual air/ground temperature 140 (Ednie and Smith, 2015; Environment Canada, http://climate.weather.gc.ca/climate_normals/index_e.html), surficial material (Cruishank, 1971;Dredge, 1994;Taylor, 1982;Throop et al, 2010), and ground ice content of near-surface permafrost (O'Neill et al, 2019), to provide background information for reference.…”

Section: Auxiliary Dataset and Informationmentioning

confidence: 99%

GPS Interferometric Reflectometry measurements of ground surface elevation changes in permafrost areas in northern Canada

Zhang

Liu

2019

Preprint

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Abstract. Global Positioning System Interferometric Reflectometry (GPS-IR) is a relatively new technique which uses reflected GPS signals to measure surface elevation changes to study frozen ground dynamics. At present, more than 200 GPS stations are in continuous operation in the Northern Hemisphere permafrost areas. They were originally designed and maintained for tectonic and ionospheric studies. However, only one site in Barrow, Alaska has so far been used to study permafrost by GPS-IR. Moreover, GPS-IR has high requirements on ground surface condition, which needs to be open, flat, and homogeneous. In this study, we screen 3 major GPS networks in Canada and identify 12 out of 38 stations located in permafrost areas as useful ones where reliable reflectometry measurements can be obtained. We narrow our focus to 5 Canadian Active Control System stations and obtain their daily GPS-IR estimated surface elevation changes. We find that the ground surface subsided in Alert and Resolute Bay respectively by 0.79 ± 0.04 cm yr−1 (2012–2017) and 0.70 ± 0.02 cm yr−1 (2003–2014), but uplifted in Iqaluit by 0.35 ± 0.04 cm yr−1 (2010–2017). At the other two sites respectively in Repulse Bay and Baker Lake, the trends are not statistically significant. The linear trends of deformation were negatively correlated with those of the thaw indices in Alert, Resolute Bay, and Iqaluit. Furthermore, in Resolute Bay, we also find that the end-of-thaw elevations during 2003–2012 were highly negatively correlated with the square root of thaw indices. This study highlights multiple useful GPS stations in northern Canada, where multi-year, continuous, and daily GPS-IR estimated surface deformation can be obtained and used to study frozen ground dynamics at various temporal scales and across a broad region.

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New ground ice maps for Canada using a paleogeographic modelling approach

Cited by 73 publications

References 128 publications

Ground ice, organic carbon and soluble cations in tundra permafrost and active-layer soils near a Laurentide ice divide in the Slave Geological Province, N.W.T., Canada

Ground ice, organic carbon and soluble cations in tundra permafrost and active-layer soils near a Laurentide ice divide in the Slave Geological Province, N.W.T., Canada

Subedi et al. (tc-2020-33) Comments

GPS Interferometric Reflectometry measurements of ground surface elevation changes in permafrost areas in northern Canada

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