What are the Canadian Shield and its significance?

The Canadian Shield is a vast region of ancient Precambrian rock covering about eight million square kilometres of central and eastern Canada, roughly half the country's land area. It curves in a horseshoe shape from Labrador through northern Quebec, Ontario, the prairie provinces, and into the Northwest Territories and Nunavut. The exposed bedrock is up to 4.28 billion years old, ranking among the oldest landscapes on Earth.

Economically the Shield is one of Canada's most productive regions. The Sudbury Basin, formed by a 1.85-billion-year-old meteorite impact, is a major source of nickel, copper, platinum, palladium, and gold for Vale, Glencore, and KGHM operations. The Athabasca Basin in northern Saskatchewan contains the world's highest-grade uranium deposits, mined by Cameco at McArthur River and Cigar Lake. Diamond mines at Ekati, Diavik, and Gahcho Kué in the Northwest Territories have produced billions of dollars of gem-quality stones since 1998.

The Shield's rivers and lakes generate hydroelectric power that supplies much of the electricity used in Quebec, Manitoba, Ontario, and Newfoundland and Labrador. Hydro-Quebec's La Grande complex and Robert-Bourassa generating station in James Bay, Nalcor's Churchill Falls station in Labrador (5,428 megawatts), and Manitoba Hydro's Nelson River system together produce more renewable energy than any comparable region in North America.

Indigenous nations including the Cree, Innu, Anishinaabe, and Dene have lived in the Shield for millennia. Modern resource agreements such as the James Bay and Northern Quebec Agreement of 1975, the 2002 Paix des Braves between Quebec and the Cree Nation, and the 1993 Nunavut Land Claims Agreement transfer royalties, decision-making, and economic benefits to Indigenous governments. The Shield's forestry industry, organised under Canadian Industries' tenure agreements, supports towns from Thunder Bay to Sept-Îles.