Canadian Shield

The Canadian Shield is a vast region of exposed Precambrian crystalline rock surrounding Hudson Bay and extending across much of eastern and central Canada. Its ancient bedrock has been extensively reshaped by glaciers.

Precambrian: The span of geological time from Earth’s formation about 4.54 billion years ago to 541 million years ago. Most Shield bedrock formed during this immense interval of Earth history.
Pleistocene glaciation: Repeated growth and retreat of large ice sheets during the Pleistocene epoch, from about 2.58 million to 11,700 years ago. Ice sheets scoured the Shield and removed much of its soil and weathered rock.
Canadian Shield mining: The extraction of metallic and other mineral resources from deposits in the Canadian Shield. Its ancient rocks host major mining districts and deposits.
Superior Craton: A large Archean cratonic block underlying much of central Canada and parts of the northern United States. It forms a major, exceptionally old core of the Canadian Shield.
Interior Plains: A broad region of sedimentary rocks and plains extending across central North America. The Interior Plains border the Shield to the west and contrast with its exposed crystalline bedrock.
Canadian Shield geology: The study of the Shield’s ancient rocks, geological provinces, structures, and mineral deposits. This field maps the region’s complex assemblage of ancient crust.
Laurentide Ice Sheet: A vast ice sheet that covered much of Canada and parts of the northern United States during the last glacial period. Its advance and retreat shaped much of the Shield’s modern surface.
Nickel: A silvery metallic element used in stainless steel, batteries, and alloys. The Sudbury region of the Shield is one of the world’s major nickel-producing areas.
Grenville Province: A belt of ancient metamorphic rocks extending along the southeastern margin of the Canadian Shield. Its high-grade rocks record major mountain-building along the Shield’s edge.
Hudson Bay Lowlands: A low-lying region of poorly drained wetlands around the southern and western shores of Hudson Bay. Sedimentary cover and wetlands distinguish these lowlands from much of the exposed Shield.

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