Borderlands: Arctic Physiographic Regions

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Abstract

Canada’s landscape is very diversified and comprises several distinctive areas, called physiographic regions, each of which has its own topography and geology. This map shows the location of the Arctic physiographic regions which include the Innuitian Region, the Arctic Lowlands and the Arctic Coastal Plains.

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The physical geography of Canada comprises two great parts: the Shield and the Borderlands. The Shield consists of a core of old, massive, Precambrian crystalline rocks. The Borderlands areas are formed by younger rocks and surround the Shield like two rings. The inner ring comprises a chain of lowlands, plains and plateaus of generally flat-lying sedimentary rocks. The outer ring consists of discontinuous areas of mountains and plateaus in which the younger rocks are deformed. Each of these areas is divided into regions, each of which comprises many smaller subdivisions that are distinctive based on their topography and geology.

The Arctic Physiographic Regions

Innuitian Region

The Innuitian Region is characterized by two zones of mountains that are separated by extensive and discontinuous terrain of more subdued topography formed by plateaus, uplands and lowlands.

The mountain ranges include the Grantland, the Axel Heiberg, and the Victoria and Albert mountains. On central Axel Heiberg Island and northwestern Ellesmere Island, the mountains are nearly buried by ice sheets through which the peaks project as a row of nunataks. Between these two large mountainous zones lies the Eureka Upland. To the south are the Perry Plateau and the Sverdrup Lowlands, a region of low relief, rolling, and scarped lowland.

The following photographs show examples of landscape found in the Innuitian Region.

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Svendsen Peninsula of Ellesmere Island, Nunavut

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Axel Heiberg Island, Nunavut

Arctic Lowlands

The Arctic Lowlands lie between the Shield and the Innuitian Region. They include the Lancaster Plateau, Foxe Plain, Boothia Plain, Victoria Lowland and Shaler Mountains.

The surface of the Lancaster Plateau slopes gently southward from about 770 metres on southern Ellesmere Island, across central Devon Island, to an average elevation of 300 to 600 metres on Somerset Island and the Brodeur Peninsula of northwestern Baffin Island. The landscape is uniformed. Farther south, the surface descends still lower until it forms the surface of the Boothia Plain on both sides of the Gulf of Boothia.

Surrounding Foxe Basin, the landscape of the Foxe Plain is low and smooth. It forms a very shallow basin-like area on the old surface, partly covered by very shallow sea. Farther west, the Shaler Mountains rise through the Victoria Lowlands.

The following photographs show examples of the landscape from the Arctic Lowlands.

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Peninsula on Baffin Island, Nunavut

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Hall Beach on the Melville Peninsula, Nunavut

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Igloolik Island, Nunavut

Arctic Coastal Plain

The Arctic Coastal Plain includes the coastal terrain along the shores of the Arctic Ocean from Meighen Island to Alaska. It is divided into three subregions, each of which has distinctive physiographic characteristics:

• The Island Coastal Plain extends from Meighen Island to Banks Island, sometimes characterized by hilly terrain that carries an ice cap and sometimes by a low, flat, uniform landscape or by low hills.
• The Mackenzie Delta includes not only the delta of the present river but remnants of earlier deltas and features built by the deposition of a mix of sediments coming from the river and from the sea. A multitude of lakes and channels cover the Mackenzie Delta plain and, in the older parts, pingos form the most outstanding features of the landscape.
• The Yukon Coastal Plain, which lies at a higher altitude than the Mackenzie Delta, appears to be largely an erosion surface cut into bedrock and mantled by a thin veneer of recent sediments.

The following photographs show examples of the landscape of the Arctic Coastal Plain.

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Prince Patrick Island, Northwest Territories

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Tuktoyaktuk, Northwest Territories