Canada

C

Geology

The Canadian Shield, which occupies the eastern half of Canada’s landmass, is an ancient craton (stable continental platform). It is made of rocks that formed billions of years ago during the Precambrian Era of Earth history and includes granites, gneisses, and schists 2 to 4 billion years old. It became the nucleus of the North American crustal plate when Earth’s crust first experienced the tectonic forces that drive continental drift (see Plate Tectonics).

In the Paleozoic Era (about 540 million to 250 million years ago), large parts of Canada were covered by shallow seas. Sediments deposited in these seas formed the sandstone, shale, and limestone that now surround the shield. During the Cambrian and Silurian periods of the Paleozoic Era, layers of rocks were formed that appear as outcroppings in Nova Scotia, New Brunswick, and Newfoundland and Labrador, along the St. Lawrence valley, and on the shores of Lake Ontario. Flat beds of Paleozoic and younger rocks extend westward across the Great Plains through the provinces of Manitoba, Saskatchewan, and Alberta. The rocks in these areas contain valuable deposits of oil and gas.

In the Canadian Cordillera, the rocks were subjected to tectonic forces generated by the collision of the North American plate with the Pacific plate. In the ensuing upheavals, which began during the Cretaceous Period (about 145 million to 65 million years ago), mountain ranges rose throughout the Canadian Cordillera. The easternmost of these ranges, the Rocky Mountains, run from Canada south through Montana, Wyoming, Colorado, and New Mexico. They were built by uplifting and folding of sedimentary rocks and, to a lesser degree, by volcanic activity. The strata composing them range in age from the Paleozoic Era to the Tertiary Period (about 65 million to 1.8 million years ago) and contain valuable deposits of metals as well as fossil fuels.

During the Pleistocene Epoch (about 1.8 million to 11,500 years ago), nearly all of Canada was covered by vast ice sheets that extended into the northern United States. As these ice sheets moved, they profoundly modified Canada’s landscapes, creating many thousands of lakes and extensive deposits of sand, clay, and gravel. See also Ice Ages.

---

---

D

Soils

Canada’s largest area of high-quality farmland is a formation of rich dark brown and black prairie, or grassland, soils that run from southern Manitoba west across Saskatchewan and into Alberta. The gray-brown soil of the St. Lawrence valley and the Great Lakes is also good farmland. Only about 5 percent of Canada’s land is suitable for raising crops, however; the remainder is too mountainous, rocky, wet, or infertile.

Large areas of Canada are covered by boggy peat that is characteristic of the tundra and adjoining forest areas. This land is generally infertile and frequently mossy. In the Arctic regions, most of the soil is classified as permafrost, meaning that at least 80 percent of the ground is permanently frozen. The freeze-thaw action that occurs in the more southern parts of the permafrost zone frequently causes so-called patterned ground features, such as polygonal rings of stones, ice wedges, and pingos (ice domes).

E

Rivers and Lakes

Canada contains more lakes and inland waters than any other country in the world. In addition to the Great Lakes on the American border (all partly within Canada except Lake Michigan), the country has 31 lakes or reservoirs of about 1,300 sq km (about 500 sq mi) in area. Canada’s two largest lakes are Superior and Huron, at 82,100 sq km (31,700 sq mi) and 59,600 sq km (23,000 sq mi), respectively. About one-third of Lake Superior and about three-fifths of Lake Huron are in Canada.

The largest lakes wholly within Canada are Great Bear, at 31,790 sq km (12,270 sq mi), and Great Slave, at 28,570 sq km (11,030 sq mi), both in the Northwest Territories. Each of these immense lakes is larger than either Lake Erie or Lake Ontario. Lake Winnipeg in Manitoba, at 24,390 sq km (9,417 sq mi), also compares in size with Lake Erie and is much larger than Lake Ontario. Other very large bodies of freshwater are Lake Athabasca and Reindeer Lake in Saskatchewan and the Smallwood Reservoir in Newfoundland and Labrador. Also significant in size are Nettilling Lake on Baffin Island, Lake Winnipegosis and Lake Manitoba in Manitoba, Lake Nipigon and Lake of the Woods in Ontario, and Lake Melville in Newfoundland and Labrador.

Canada’s two greatest rivers are the St. Lawrence, which drains the Great Lakes and empties into the Gulf of St. Lawrence, and the Mackenzie, which empties into the Arctic Ocean and drains a large part of northwestern Canada. While the St. Lawrence is the largest river in Canada in volume of water discharged at its mouth, the Mackenzie is the longest. Through its tributary, the Peace River, and tracing to its source in the Finlay River of British Columbia, the Mackenzie is 4,241 km (2,635 mi) long and is one of the longest rivers in the world. The St. Lawrence and the Mackenzie are the second and third largest rivers by volume of discharge, respectively, in North America.

Other large Canadian rivers in terms of both length and discharge are the Yukon, flowing from Yukon Territory across Alaska into the Bering Sea; the Nelson-Saskatchewan system, flowing across the Great Plains into Hudson Bay; the Churchill, also flowing into Hudson Bay; and the Fraser and the Columbia in British Columbia. Other significant regional rivers are the Saint John, emptying into the Bay of Fundy between Nova Scotia and New Brunswick; the Churchill, in Newfoundland and Labrador; and the many rivers flowing into the St. Lawrence from the shield, including the Ottawa, the Saguenay, and the Saint-Maurice. All these rivers are navigable for at least some of their length, but only the St. Lawrence and Mackenzie are used for commercial navigation.

In general, all rivers and lakes in Canada have value as sources of water for agricultural, industrial, urban, and recreational uses; but some have more specific commercial uses. The St. Lawrence Seaway and the Great Lakes together form an important transportation network for eastern Canada, allowing oceangoing vessels to travel deep into the heartland. The Great Lakes are used to transport bulk materials, such as grain and iron ore, and have been important for the industrial development of the St. Lawrence-Great Lakes region.

Many of the rivers emptying into the St. Lawrence are also important producers of hydroelectric power. In contrast, the rivers of the Arctic drainage basin have little commercial importance. Although the Mackenzie is navigable for most of its length and has been used for transportation, its isolation limits its usefulness. The rivers draining into Hudson Bay are important primarily as power sources, particularly the Nelson in northern Manitoba and the La Grande in northern Québec. The fast-flowing rivers draining into the Pacific, such as the Fraser, are particularly suitable for power generation. They are also crucial for the salmon fishing industry, but these two uses are not compatible. For this reason, hydroelectric development has been prohibited on the Fraser.

F

Coastline

The coast of the Canadian mainland, about 58,500 km (about 36,350 mi) in length, is extremely broken and irregular, with alternating large bays and peninsulas. Canada also has numerous coastal islands, with a total island coastline of about 185,290 km (about 115,130 mi). Off the eastern coast the largest islands are Newfoundland, Cape Breton, Prince Edward, and Anticosti. Off the western coast, which is fringed with fjords, are Vancouver Island and the Queen Charlotte Islands. Hudson Bay contains Southampton Island and many smaller islands. The Canadian Arctic Archipelago contains many large and small islands, the largest of which are Baffin, Ellesmere, and Victoria.

The importance of the coastline lies in the access it provides to marine resources. Canada has jurisdiction over resources in the oceans that are within 200 nautical miles (230 mi/370 km) of its shores. It has exclusive rights to the resources within that zone, including fisheries and oil deposits. The most important oil sources at present are the Hibernia Oilfields off Newfoundland and Labrador and the Sable Island reserves off Nova Scotia.

The coastline is also important because it provides many natural harbors that have been developed into ports. Ocean ports handle much of Canada’s international trade and provide a significant portion of local and regional coastal economies. Of course, the commercial value of the coastline varies with location; the southern coasts and their ports, such as Vancouver and Victoria in the west and Halifax in the east, are much more important than similar locations in the north, which are icebound much of the year. Finally, coastlines in Canada are very scenic and attract visitors from around the world.

G

Climate

Because of its size, Canada has a great variety of climatic conditions. Part of the mainland and most of the Canadian Arctic Archipelago are within Earth’s north frigid zone; the remainder of the country lies in the northern half of the north temperate zone. Climatic conditions range from the extreme cold of the Arctic regions to the moderate temperatures of more southerly latitudes. Average summer temperatures range from 8°C (46°F) in the far north to more than 22°C (72°F) in some parts of the far south. Average January temperatures range from -35°C (-31°F) in the far north to 3°C (37°F) in southwestern British Columbia. Similarly, precipitation ranges from near-desert conditions of less than 300 mm (12 in) per year in the far north to very wet conditions of more than 2,400 mm (more than 90 in) in parts of the west coast. Therefore, there is no single Canadian climate, but rather several regional climates.

In the Atlantic provinces, the ocean lessens the extremes of winter cold and summer heat but also causes considerable fog and precipitation. The Pacific coast, which is influenced by warm ocean currents and moisture-laden winds, has mild summers and winters, high humidity, and abundant precipitation. In the Canadian Cordillera, the higher western slopes of certain uplifts, particularly the Selkirks and the Rockies, receive sizable amounts of rain and snow. The eastern slopes and the central plateau receive little precipitation. In the eastern Canadian Cordillera, the chinook, a warm, dry westerly wind, makes winters substantially less severe in the Rocky Mountain foothills and adjoining plains. The Prairie provinces (Alberta, Manitoba, and Saskatchewan) are marked by the most extreme ranges of summer heat and winter cold in Canada. Eastern Canada (Ontario and Québec), which also has great variations in heat and cold, is the snowiest region in Canada.

Climate has been a factor in the development of Canada because people have settled where temperatures are warmest and agricultural growing seasons longest. Climate also influences vegetation, producing, for example, the rain forest of coastal British Columbia. Southern Ontario and southwestern British Columbia have the mildest climates and greatest population densities in Canada. In contrast, the central and northern regions are sparsely populated. The permafrost region in the north poses great challenges for settlement and development. Yukon Territory, the Northwest Territories, the Nunavut Territory, northern Québec and Labrador, and the far northern areas of Ontario and Manitoba are all affected by this condition. Houses, roads, runways, and pipelines require special, expensive adaptations. Water and sewage lines are especially troublesome to maintain. Permafrost also makes mining and other forms of development more difficult and environmentally damaging. Disruption of the environment through development can induce thermokarst, the formation of thaw lakes into which buildings can sink.

	More from Encarta
	•  Presidential Myths Quiz •  Coffee break: Recharge your brain