The map shows the location of the continuous permafrost zone and the discontinuous permafrost zone including areas of wide spread permafrost, areas of scattered permafrost and permafrost areas in the Cordillera. The map also indicates for six locations (Inuvik, Yellowknife, Thompson, Resolute, Rankin Inlet and Schefferville) the thickness of permafrost in metres and the ground temperature. Permafrost is a term used to describe the thermal condition of earth materials, such as soil and rock, when their temperature remains below 0 degrees Celsius continuously for more than 1 year. One-half of Canada's land surface is underlain by permafrost. The permafrost region is divided into two zones: continuous in the north and discontinuous in the south. In the continuous zone, permafrost exists everywhere beneath the land surface and varies in thickness from about 100 metres at the southern limit to 1000 metres in the Far North. The active layer usually extends down to the permafrost. In the discontinuous zone, some areas have permafrost beneath the land surface and other areas are free of permafrost. The distribution ranges from widespread in the north, where permafrost areas predominate, to scattered, where permafrost occurs in islands in generally unfrozen terrain. It varies in thickness from a few metres or less at the southern limit to about 100 metres at the boundary with the continuous zone. The active layer does not extend down to the permafrost in all places. South of the discontinuous zone, a few patches of permafrost exist in peatlands owing to unusual microclimatic and terrain conditions. The thickness of permafrost is influenced by such factors as soil and rock type, snow cover, and proximity to bodies of water. The values shown on the map were obtained by different methods such as direct observation in boreholes, mine shafts, and wells; ground-temperature measurements using thermocouple and thermistor cables; and geophysical methods, including seismic and resistivity. Other factors that affect permafrost conditions include relief, vegetation, hydrology, snow cover, fire, glacier ice, and soil and rock type.
- Publisher - Current Organization Name: Natural Resources Canada
- Licence: Open Government Licence - Canada
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