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Nunavut's landscape tells the story of billions of years of geological history, from ancient Canadian Shield bedrock to features carved by recent ice ages. Permafrost underlies virtually the entire territory.
Ground that remains frozen for at least two consecutive years
Ancient Precambrian bedrock—among the oldest on Earth
Landforms shaped by ice sheets that retreated 10,000 years ago
Permafrost is ground that remains at or below 0°C for at least two consecutive years. In Nunavut, continuous permafrost underlies the entire territory, with depths ranging from a few meters in the south to over 600 meters in the High Arctic.
Above the permafrost lies the "active layer"—soil that thaws each summer and refreezes in winter. This thin layer, typically 30-100 cm deep, supports all plant life and creates challenges for construction and infrastructure.
Permafrost creates distinctive landforms that are actively studied as indicators of climate change. These features are unique to Arctic and subarctic regions.
Ice-cored hills that form when water freezes and expands under the permafrost surface, pushing up the ground into dome-shaped mounds. Can reach 50m in height.
Where found: Common in Mackenzie Delta region, present in western Nunavut
Geometric patterns of cracks in the ground surface created by repeated freezing and thawing cycles. Ice wedges form in the cracks over thousands of years.
Where found: Widespread across Nunavut tundra
Irregular, hummocky terrain and lakes formed when ice-rich permafrost thaws and the ground subsides. An indicator of climate change.
Where found: Increasing across the Arctic due to warming
Peat mounds with a permanently frozen core, typically 1-7m high. They form in wetland areas where peat insulates ice beneath.
Where found: Southern Nunavut and transition zones
Climate change is causing permafrost to thaw at unprecedented rates. According to research published in Nature Climate Change, permafrost temperatures have increased by 0.3-0.4°C per decade since the 1980s.