Near-surface ground-ice distribution, Kendall Island Bird Sanctuary, western Arctic coast, Canada

2009 ◽  
Vol 20 (2) ◽  
pp. 155-171 ◽  
Author(s):  
P. D. Morse ◽  
C. R. Burn ◽  
S. V. Kokelj
Keyword(s):  
Ground Ice ◽  
Near Surface ◽  
Western Arctic ◽  
Arctic Coast

Physical and temporal factors controlling the development of near-surface ground ice at Illisarvik, western Arctic coast, Canada

2012 ◽  
Vol 49 (9) ◽  
pp. 1096-1110 ◽  
Author(s):  
H. Brendan O’Neill ◽  
C.R. Burn
Keyword(s):  
Important Variable ◽  
Lake Basin ◽  
Ground Ice ◽  
Near Surface ◽  
Marginal Areas ◽  
Permafrost Table ◽  
Western Arctic ◽  
Arctic Coast ◽  
Ice Content ◽  
Secondary Variable

Near-surface permafrost was sampled in summer 2010 at 26 sites in the Illisarvik drained-lake basin and nine sites in the surrounding tundra on Richards Island, NWT, to investigate the growth of segregated near-surface ground ice. Permafrost and ground ice have developed in the lake basin since drainage in 1978. The lake bed soils are predominantly silts of varying moisture and organic-matter contents, with sandier soils near the lake margins. Excess-ice contents in the basin were also variable, and ice enrichment was observed to a maximum depth of 60 cm below the 2010 permafrost table. Shrub-covered, wet areas had the highest mean excess-ice content in the top 50 cm of permafrost (10%), while grassy, dryer areas (4%) and poorly vegetated marginal areas (<1%) were less enriched with ice. Site wetness was the most important variable associated with near-surface excess-ice content in the lake basin. Silt content was a secondary variable. Mean excess-ice content in the top 50 cm of permafrost at tundra sites (25%) was much greater than in the basin, with ice enrichment to greater depths, likely a result of the time available for permafrost aggradation since the early Holocene climatic optimum.

scholarly journals New ground ice maps for Canada using a paleogeographic modelling approach

2019 ◽  
Vol 13 (3) ◽  
pp. 753-773 ◽  
Author(s):  
H. Brendan O'Neill ◽  
Stephen A. Wolfe ◽  
Caroline Duchesne
Keyword(s):  
Glacial Lake ◽  
Significant Advance ◽  
Small Scale ◽  
Permafrost Degradation ◽  
Field Observations ◽  
Tree Line ◽  
Ground Ice ◽  
Near Surface ◽  
Western Arctic ◽  
Modelling Approach

Abstract. Ground 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.

scholarly journals New ground ice maps for Canada using a paleogeographic modelling approach

2018 ◽  
Author(s):  
H. Brendan O'Neill ◽  
Stephen A. Wolfe ◽  
Caroline Duchesne
Keyword(s):  
Glacial Lake ◽  
Significant Advance ◽  
Small Scale ◽  
Permafrost Degradation ◽  
Field Observations ◽  
Tree Line ◽  
Ground Ice ◽  
Near Surface ◽  
Western Arctic ◽  
Modelling Approach

Abstract. Ground 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 (massive ice and icy sediments, 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 massive ice and icy sediments 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 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 tree line advanced during warmer periods. Published observations of thaw slumps and 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 some 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 Origin of Massive Icy Beds in Permafrost, Western Arctic Coast, Canada

1971 ◽  
Vol 8 (4) ◽  
pp. 397-422 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
The Arctic ◽  
Ground Ice ◽  
Widespread Occurrence ◽  
Sea Floor ◽  
Western Arctic ◽  
Arctic Coast ◽  
Ice Content ◽  
Glacier Advance ◽  
Drill Holes ◽  
Level Lowering

Massive beds of ground ice are shown to exist along the arctic coastal plain east of the Alaska–Yukon boundary for a distance of at least 500 km. The massive ground ice can be seen in both undisturbed and glacially disturbed Pleistocene sediments. An examination of several thousand seismic shot hole logs, from drill holes of 15 to 35 m in depth, also corroborates the widespread occurrence of ground ice. The icy beds typically have an ice content, defined in terms of the weight of ice to dry soil, in excess of 200% for sections as much as 35 m thick. A theory is presented which suggests that: the ice is of segregation origin; the source of excess water was from the expulsion of ground water during the freezing of sands; and high pore water pressures, favorable to ice segregation, developed beneath an aggrading impermeable permafrost cover. Permafrost aggradation may have occurred either on an exposed sea floor during a period of sea level lowering which would have accompanied a glacier advance, or following a warm interval in which there had been deep thaw. Similarities in the origin of pingo ice and massive ice are discussed.

The Growth of Pingos, Western Arctic Coast, Canada

1973 ◽  
Vol 10 (6) ◽  
pp. 979-1004 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Growth Rate ◽  
Pore Water ◽  
Closed System ◽  
Water Pressure ◽  
Ice Core ◽  
Growth Stages ◽  
Size And Shape ◽  
Western Arctic ◽  
Arctic Coast ◽  
Strong Control

The growth rates of 11 closed system pingos have been measured, by means of precise levelling of permanent bench marks anchored well down into permafrost, for the 1969–1972 period. As pingo growth decreases from the summit to the base, growth of the ice-core decreases from the center out to the periphery. The pingos have grown up in the bottoms of lakes which have drained rapidly and thus become exposed to permafrost aggradation. The specific site of growth is usually in a small residual pond where permafrost aggradation is retarded. The size and shape of a residual pond exercises a strong control upon the size and shape of the pingo which grows within it. The ice-core thickness equals the sum of the pingo height above the lake flat and the depth of the residual pond in which the pingo grew. Pingos tend to grow higher rather than both higher and wider. Pingos are believed to grow more by means of ice segregation than by the freezing of a pool of water. The water source, and the associated positive pore water pressure, result from permafrost aggradation in sands and silts in the lake bottom under a closed system with expulsion of pore water. The fastest growth rate of an ice-core, for the Western Arctic Coast, is estimated at about 1.5 m/yr, for the first one or two years. After that, the growth rate decreases inversely as the square root of time. The largest pingos may continue to grow for more than 1000 yr. Four growth stages are suggested. At least five pingos have commenced growth since 1935. As an estimate, probably 50 or more pingos are now growing along the coast.

scholarly journals Ground ice in the Northern Foothills, northern Victoria Land, Antarctica

2004 ◽  
Vol 39 ◽  
pp. 495-500 ◽  
Author(s):  
Mauro Guglielmin ◽  
Hugh M. French
Keyword(s):  
Oxygen Isotope ◽  
Ross Sea ◽  
Progress Report ◽  
Ground Ice ◽  
Lake Ice ◽  
Near Surface ◽  
Victoria Land ◽  
Different Types ◽  
Glacier Ice ◽  
Surface Ice

AbstractThis progress report classifies the different types of ground-ice bodies that occur in the Northern Foothills, northern Victoria Land, Antarctica. Oxygen isotope variations are presented, but interpretation is kept to a minimum pending further investigations. Surface ice, as distinct from moving glacier ice, occurs in the form of widespread buried (‘dead’) glacier ice lying beneath ablation (sublimation) till, together with perennial lake ice, snow banks and icing-blister ice.’Dry’ permafrost is uncommon, and interstitial ice is usually present at the base of the active layer and in the near-surface permafrost. This probably reflects the supply of moisture from the Ross Sea and limited sublimation under today’s climate. Intrusive ice occurs as layers within perennial lake-ice covers and gives rise to small icing blisters. Small ice wedges found beneath the furrows of high-centered polygons appear to agree with the model of sublimation-till development proposed by Marchant and others (2002).

scholarly journals Ground ice, organic carbon and soluble cations in tundra permafrost soils and sediments near a Laurentide ice divide in the Slave Geological Province, Northwest Territories, Canada

2020 ◽  
Vol 14 (12) ◽  
pp. 4341-4364
Author(s):  
Rupesh Subedi ◽  
Steven V. Kokelj ◽  
Stephan Gruber
Keyword(s):  
Organic Carbon ◽  
Landscape Change ◽  
Ice Sheet ◽  
Canadian Arctic ◽  
Landscape Changes ◽  
Ground Ice ◽  
Basal Ice ◽  
Permafrost Soils ◽  
Western Arctic ◽  
Mineral Soils

Abstract. The central Slave Geological Province is situated 450–650 km from the presumed spreading centre of the Keewatin Dome of the Laurentide Ice Sheet, and it differs from the western Canadian Arctic, where recent 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 in some areas, creating a mosaic of permafrost conditions. Limited evidence of ice-rich ground, a key determinant of thaw-induced landscape change, exists. Carbon and soluble cation contents in permafrost are largely unknown in the area. Twenty-four boreholes with depths up to 10 m were drilled in tundra north of Lac de Gras to address these regional gaps in knowledge and to better inform projections and generalizations at a coarser scale. Excess-ice contents of 20 %–60 %, likely remnant Laurentide basal ice, are found in upland till, suggesting that thaw subsidence of metres to more than 10 m is possible if permafrost were to thaw completely. Beneath organic terrain and in fluvially reworked sediment, aggradational ice is found. The variability in abundance of 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 nature and spatial patterns of landscape changes, however, are expected to differ from ice-marginal landscapes of western Arctic Canada, for example, based on greater spatial and stratigraphic heterogeneity. Mean organic-carbon densities in the top 3 m of soil profiles near Lac de Gras are about half of those reported in circumpolar statistics; deeper deposits have densities ranging from 1.3–10.1 kg C m−3, representing a significant additional carbon pool. The concentration of total soluble cations in mineral soils is lower than at previously studied locations in the western Canadian Arctic. This study can inform permafrost investigations in other parts of the Slave Geological Province, and its data can support scenario simulations of future trajectories of permafrost thaw. Preserved Laurentide basal ice can support new ways of studying processes and phenomena at the base of an ice sheet.

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