User talk:Razor shark
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Canadian Shield— also called the Precambrian Shield, Laurentian Shield, Bouclier Canadien (French), or Laurentian Plateau— is a large shield covered by a thin layer of soil that forms the nucleus of the North American craton. It has a deep, common, joined bedrock region in eastern and central Canada and stretches North from the Great Lakes to the Arctic Ocean, covering half the country. It also includes most of Greenland and extends into the United States as the Adirondack Mountains and the Northern Highland. The Canadian Shield is U-shape, but almost circular, which gives it an appearance of a warrior's shield or a giant horseshoe, and is a subsection of the Laurentia craton signifying the area of greatest glacial impact (scraping down to bare rock) creating the thin soils.
The Canadian Shield was the first part of North America to be permanently elevated above sea level and has remained almost wholly untouched by successive encroachments of the sea upon the continent. It is the earth's greatest area of exposed Archaean rock. The metamorphic base rocks are mostly from the Precambrian Era (between 4.5 billion and 540 million years ago), and have been repeatedly uplifted and eroded. Today it consists largely of an area of low relief (1,000–2,000 ft/305–610 m above sea level) with a few monadnocks and low mountain ranges (including the Torngat and Laurentian Mountains) probably eroded from the plateau during the Cenozoic era. During the Pleistocene epoch, continental ice sheets depressed the land surface (see Hudson Bay), scooped out thousands of lake basins, and carried away much of the region's soil.
Hydrographical drainage is generally poor, the effects of glaciation being one of the reasons. The Canadian shield is covered by boreal forests in the south, while tundra prevails in the northern regions. Population is scarce, and industrial development is generally poor[1], however the region has a large water-power potential and is a source of ore and timber. Many mammals such as caribou, wolverines, weasels, mink, otters, grizzlies and black bears are also present in this area[2].