Canadian Shield

The Canadian Shield, also called the Laurentian Shield or the Laurentian Plateau, is a large area of very old rocks that form the ancient heart of North America. It is made from Precambrian igneous and metamorphic rocks, which means these rocks are some of the oldest on Earth and were formed from cooled lava and changed by heat and pressure over time. This area makes up the North American Craton (or Laurentia), the central part of the North American continent.

Because of glaciation, the Canadian Shield has only a thin layer of soil covering it, so you can often see the old bedrock sticking out. This bedrock comes from a time when there was lots of volcanic activity. The Canadian Shield stretches from the Great Lakes all the way up to the Arctic Ocean, covering more than half of Canada and parts of Greenland. It even reaches into the northern parts of the United States. This huge rocky area is very important for understanding Earth's history and the land we live on today.

Geographical extent

The Canadian Shield is a big area of very old rocks that makes up the core of North America. It includes parts of many places such as Quebec, Ontario, Manitoba, and even stretches into the United States, including the Adirondack Mountains in New York. This area was heavily shaped by glaciers, which scraped away soil and left thin layers over the rocks.

Long ago, this region had tall mountains, but over millions of years, they were worn down to gentle hills. Today, it is a flat area with some higher spots and many lakes created by ancient ice sheets. When you include Greenland, the Canadian Shield forms a huge circular area covering about 8,000,000 km² (3,100,000 mi²).

Geology

The Canadian Shield is one of the oldest areas on Earth, with some parts dating back 2.5 to 4.2 billion years. It has many rivers and lakes because glaciers long ago changed the land's shape. Once, this area had very tall mountains and lots of volcanic activity, but over time, erosion wore them down. Now we see the roots of those old mountains, which appear as greenstone belts—bands of volcanic rock surrounded by granitic rock. These rocks are very old, from about 3.6 to 2.7 billion years ago.

The Canadian Shield is the largest exposed part of North America’s ancient core, called the North American craton. It includes special rock formations like the Sturgeon Lake Caldera in Ontario and the huge Mackenzie dike swarm. Even though the mountains here are worn down, Canada’s far north still has tall mountains, such as the Arctic Cordillera, with Barbeau Peak being the highest at 2,616 metres above sea level. The shield’s bedrock is mostly made of very old Precambrian rock.

Ecology

The Canadian Shield has very thin soil on top of rocks, mostly left bare after ice ages scraped the land clean. In the south, there are thick forests, while the north has colder, less dense forests and areas of tundra. The land has many lakes and rivers that are home to fish like walleye and northern pike, as well as birds such as Canada geese and loons.

The area is also home to animals like beavers, caribou, moose, wolves, and bears. Some polar bears make their homes in places like Wapusk National Park. The forests and lakes support many different plants and animals, making it an important natural home for many species.

Mining and economics

The Canadian Shield is very rich in valuable minerals such as nickel, gold, silver, and copper. Many towns in this area have mines that dig up these minerals. One of the most famous places is Sudbury in Ontario. Sudbury is special because it sits on an ancient crater made by a meteorite.

Another important area is the Flin Flon greenstone belt in Manitoba and Saskatchewan, which has lots of copper, zinc, and gold. Recently, big discoveries of diamonds have been made in the Northwest Territories. These diamonds come from deep in the Earth and are brought to the surface by special kinds of volcanic eruptions. The Diavik mine, Canada’s longest-running diamond mine, stopped producing diamonds in 2026 after 23 years.