The horseshoe-shaped Canadian shield is the largest continental shield. It resembles an ancient shield held up to defend North America. A shield is a large area of exposed Precambrian igneous and metamorphic rocks. This geological shield is also known as Laurentian Plateau.
Arctica was an ancient continent formed billions of years ago during the Neoarchean era. The Canadian shield is a part of the Arctica continent. It is the largest exposed part of the crust. The crust is also known as the North American craton and it is the ancient geological centre of the North American continent.
The North American craton is also called Laurentia. The carton is an interior portion encompassing ancient crystalline basement rocks. The shield is the exposed section of a craton’s old rocks.
Canada has 7 major physiographic regions. They are Canadian Sheild, Hudson bay Lowland, Arctic plains, Interior Plains, Cordillera, Great Lakes – St. Lawrence Lowlands, and Appalachian Uplands. The Canadian Shield is the earth’s largest area of exposed Archean rocks.
Canadian shield region extends up to 8 million square kilometres. As the name itself indicates it covers around 50% of Canada. Centred on Hudson Bay, it extends from the Great Lakes to the Canadian Arctic ocean and into Greenland and USA.
In the USA, the Canadian shield prolongs to the Adirondack Mountains of New York and the Superior Upland region of the Midwest. It covers most areas of Greenland and the shield acquires an approximately circular shape here.
From the Labrador coast on the east, the shield covers most of Quebec and extends into Ontario and Manitoba in Canada. Hudson bay occupies the central part of the shield. All the major cities of Canada are situated on this shield. The northeastern territories are marked by a line extended north from the Alberta border.
The Human population is sparse in the northern regions of the shield. This owes to the fact that the climate is very harsh in the northwest territories.
2. Formation of the Canadian shield
Tectonic force, erosion, and glaciation played a significant part in forming the shield. Tectonic force is the energy that can cause movements in the earth’s crust and glaciation is the process by which glaciers cover the earth’s surface. Erosion is a geological process in which the materials of the earth are worn away and transported from one place to another by natural forces.
Some of the oldest rocks in the world were found in this region, which points to the age of the shield. The oldest rock found from here was estimated to be formed after 300 years of the formation of the earth itself.
Around 3.5 billion years ago, the Canadian shield first developed as a component of the earth’s crust. After 500 million ( during the Precambrian era) the temperature on earth cooled down and igneous rocks were formed. During the ice ages, the glaciers wore down the mountains of this region leaving only a thin layer of soil on the earth’s surface of this region.
Billion years ago, this region was characterized by high mountains which were taller than the highest mountains of today. Mountains eroded due to glaciation and erosion and leave the area with low mountain ranges. The major force behind the beautification of the Canadian landscape is glaciation. Wisconsin glaciation was the most latest glaciation and covered the region with an ice sheet of 3 km thickness.
In Baffin Island and northern Labrador, the land rises to more than 5000 feet above sea level as the northeastern part of the shield is tilted. Baffin Island is the fifth largest island in the world and the largest island in Canada.
3. Subdivisions of the region
One of the attractive features of the shield region is the similarity of the terrains. This is the result of many natural processes like erosion, glaciation, etc. The Canadian shield has 4 subregions. They are the Laurentian Upland, Kazan Region, Davis, and James. These sub-regions also have subdivisions.
The Laurentian Upland encompasses uplands and high land and it is also referred to as the Laurentian region. The Laurentian mountain range is one of the oldest mountains in the world and is located in Quebec, Canada. Kazan has diversified landscape features. Precambrian rocks from the base of the Kazan region.
James region lies to the south of the Hudson river. This region showcases the attributes of the shield. Davis region has a broad landscape without the deposit of unconsolidated materials. It extends to northern Labrador.
4. Compositions of the shield
The exposed crust of the North American craton is mainly composed of granite. These granites are highly metamorphosed. It also encompasses metamorphosed sedimentary and igneous rocks. Though the rocks are resistant to erosion but have been subjected to glaciation which had a tremendous effect on the features.
Some of the world’s oldest rocks have been found in this shield. The rocks are rich in metallic minerals such as nickel, silver, copper, and gold. They serve as one of the major sources of economy.
5. Physical features of the Canadian shield
The major features of the region are bare rocks, rolling hills, plateaus, the thin layer of soil over the surface, and numerous water bodies. The region was covered with thick sheets of ice during the ice age. The ice age is the period during which the majority of the earth’s surface was covered with thick sheets of ice. Continuous wearing down by ice, that is erosion, has worn down the height of this region.
Glaciation and erosion of the region resulted in the formation of basins. Later these basins formed rivers and swamps. Muskeg is a swamp or bog formed in North America. The region is highly swampy.
The general slope of the river is towards the Hudson river. It is surrounded by the Canadian shield and the rivers originating on the northern side of the shield flow and fall in this river.
The Canadian Shield is famous for the presence of numerous lakes which shows a deranged canal system. The lakes Superior, Michigan, Huron, Erie, and Ontario form the southern side of the Canadian shield. This chain of lakes provides 84% of North America’s surface fresh water. These water bodies together are known as The great lake basins. They enclose a large part of the USA and Canada.
More than 12000 lakes are in Quebec and Ontario alone. Smaller lakes occur throughout the shield region and are more commonly found in the highlands of Quebec and Labrador and are least common in east-central Saskatchewan and the Hudson Bay lowlands of northern Ontario.
The largest freshwater lake, Superior lake is located in the Canadian shield. The renowned Niagra falls is located between the lakes of Ontario and Erie. A quarter of the shield’s landform is in blues.
The land surface of the Canadian shield is varied with the presence of both flat and rocky areas. In the early period, the region was characterized by mountains and their height. Due to erosion, the mountains were worn down. Most of the terrain is not very mountainous in present-day Canada. The highest peak is Mt Mount Caubvick with a height of only 5420 ft.
The Canadian Shield is named Laurentian Shield after the Laurentian Plateau situated on the southeastern part of the shield. The Labrador plateau occupies the northeastern position of the shield. It is higher than the Laurentian Plateau and is dissected in nature. Moreover, the highest point of the plateau is Mt Mount Caubvick.
The climate varies across the region due to the vastness of the land. When you move towards the northwest territories, the temperature decreases. Though the climate is dry throughout the year, there is precipitation. The dry weather does not facilitate the growth of plants thus explaining the scarcity of vegetation.
Since the Canadian shield is close to the Artic, the region experiences more coldness. The days are warmer and the nights are cooler. Particularly the portion towards the northern side experiences less rainfall. The Canadian shield gets 200-300 mm of precipitation and the region receives most of the rain in August.
The Hudson river is frozen from December to June. The water is freezing even in the summertime in the region. The bay freezes for six months a year. This causes substantial transportation difficulties for minerals, forestry, and timber.
The northernmost part of the region is frozen for most of the year. The region has coarse soil which does not have retention of moisture. In the lowlands, the soil is very dense and does not facilitate forestation.
The Canadian shield is covered with only thin layers of soil and the majority of the region is occupied by water bodies. The land is rich in mineral sources such as silver, gold, and nickel.
The Boreal forest monopolizes the vegetation of the Canadian region. They are characterized by their ability to withstand harsh temperatures all round year. Spruce, Fir, and Pine are some of the majority of trees that grow here. Russia, Alaska, and Canada are characterized by the presence of Boreal forests.
The boreal forest is the largest forest region. The fragility of the trees growing here makes them highly suitable for papermaking. White and black spruce are grown abundantly in this region. White spruce is widespread in the region of Ontario and Black spruce can be found in the territory of the region.
The northern part of the Canadian shield is marked by the abundance of tundra vegetation. Short shrubs, mosses, lichens, and the scattered presence of trees are visible in this vegetation. as this area is nearer to the Arctic region the growth of trees gets stunted. Deciduous trees are also found here. The southern part of the Canadian shield has a mixed vegetation of coniferous and deciduous trees.
Numerous species can be found here, making the Canadian shield’s wildlife life extremely diverse. A long range of mammals is here such as moose, bison, beavers, wolves, foxes, and hares. Wood Buffalo national park is the largest national park in Canada. Though the park is home to many species, the park houses the largest free-roaming herd of bison.
The presence of three wildcat species, the lynx, the bobcat, and the cougar (mountain lion), points to the diversity of species in the region. There is also the presence of bears. The world’s polar bear capital, Churchill, is in northern Manitoba.
Birds such as ravens, loons, white-throated sparrows, and both boreal owls and great horned owls can be found in this Canadian shield. The presence of thousands of waterbodies makes a congenial atmosphere for the fishes like Smallmouth bass and lake trout.
The changing climatic conditions are highly endangering many species of animals. Hooping Crane, Eskimo Curlew, and Northern Bobwhite are some of the species in the face of extinction.
6. Resources on the Canadian shield
The Canadian shield is one of the world’s richest areas in mineral deposits. There are huge deposits of nickel, gold, silver, copper, iron, uranium, and diamonds. Mining began in the 19 century and became a key factor in the economic development of Canada. Canada’s major ore deposits are in the Canadian shield.
Throughout the shield, there are many mining towns extracting these precious minerals. Major discoveries of minerals especially gold had opened a new prospect to the mining sector. Gold was first discovered in 1866 in Ontario. Gold mines are still active near Kirkland lake and Timmins. Though Kirkland lake is renowned for gold mining, it also has produced legendary hockey players.
Metals like copper, nickel, gold, and palladium are mined from the mines in the Sudbury basin. Ekati was Canada’s first diamond mine which was opened in the year 1988. The largest deposit of diamonds is found in the Lac de Gras, northwest territories.
Diamonds formed billion years ago are found today. They were 50 km from the earth’s surface and brought to the surface by volcanic actions. With the Canadian shield being a part of the ancient continent, the kimberlite diamonds are found here.
At present-day, Canada has become one of the 5 largest producers of diamonds. Mining has increased exponentially with actively mining kimberlite diamonds in Northwest Territories, Wawa, Ontario, and Chapleau, Ontario.
There are substantial deposits of iron ore in the Canadian shield region. Mont Wright mine in Quebec produces the largest iron ore as most of Canada’s iron ore deposits are at Labrador Trough.
Three main sectors, solid wood manufacturing, paper, and pulp and logging make up the Canadian forest industry. The boreal forest region is known for forestry as approximately 80 percent of the forested land in this region
The vegetation helps the economy in a multitude of ways. The fragility of the trees makes them suitable for the paper and pulp-making industries. Thus the spruce, pine, and fir trees are actively used for making papers.
The fur trade is another source of the Canadian economy. The highest level of fur tapping is in Ontario, Alberto, and Quebec. Canadian fur products are exported to Europe, Asia, and the USA.
The presence of numerous water bodies makes it the source of hydroelectricity. This is the foremost reason Canada is the world’s third-largest producer of hydroelectricity. Churchill Falls, Labrador, James Bay, and Québec are the regions producing the highest amount of electricity. 59.3 percent of the country’s electricity supply is through hydroelectricity.
7. Tourism, a source of Economy on the bare rock of the Canadian shield
The scenic beauty of the irregular landscape never failed to attract tourists towards them. The Canadian shield provides an endless choice of tourist destinations. One can fish, camp, hike, or can enjoy nature peacefully in its lap. The region encompasses northwest territories, Quebec, Alberto, Labrador, and Ontario.
Northwest Territories had always been one of the must-see places on the list of travellers. They offer varieties of views to nature lovers and can relieve the burgeoning appetite for adventure. Wood Buffalo National Park is a UNESCO world heritage site aimed to protect the wood buffalo.
Quebec, a piece of Europe in Canada, is renowned for Château Frontenac. The city has extensive defenses in the European style and a long history. There are numerous gardens and museums throughout the city. Mont-Tremblant on the Laurentian mountain is the most popular ski destination and offers year-round activities.
The uniqueness of Alberto lies in its diverse landscape ranging from rolling hills to foothills and rocky mountains. Alberto also houses the most imposing national park in Canada, the Banff National Park. The Vermilion Lakes, Lake Minnewanka, and Lake Louise always steal the hearts of travellers. Alberta also has economic importance as it is the third largest reserve of crude oil.
The two splendid historic structures of Canada, the Red Bay, and Battle Harbour are situated in Labrador. The northern lights can be seen from here. The best time to visit this place is during the summer. Torngat Mountains National Park gives visitors a wonderful hiking experience and the breathtaking beauty of the whales.
Ontario is Canada’s main economic hub and offers a diverse visual treat to visitors. Northern Ontario, lying to the north of lake Huron, is perfect for outdoor activities, fishing, and hunting. The place can be visited in both the summer and winter seasons. Niagara Falls is one of the most visited places in the world. The CN Tower is Canada’s emblematic structure located in Toronto, Ontario.
Pukaskwa National Park, known for the pleasing view of Lake Superior, is located in the heart of the boreal forest ecozone of Canada. Hiking is the most preferred activity in the park by travellers.
8. Environmental problems on the Canadian shield
The resources themselves destroy the environment. Mining is the foremost source of income. Many natural resources of the Canadian shield are overused. Around 1.5 million people depend on mining to earn their livelihood and have already mined large portions of the region.
The extraction of minerals releases toxic gases into the atmosphere. Mines frequently contaminate the water, the terrain, and the local ecosystem. They have been connected to a spike in human illness and animal deaths.
Acid rain affects the vegetation of the shield. The water bodies do not have natural alkalinity and they cannot naturally neutralize the acidity. Lakes and soils of northeastern Alberta, northern Saskatchewan and Manitoba, and parts of western British Columbia are also highly responsive to acid toppling.
Deforestation for the advancement of the forest industry is the prime environmental disaster. Trees are chopped down immensely for timber, paper, and pulp-making industries. Cutting down trees endangers other living organisms.
Around seven million people live in the Canadian shield. The cultural ethnicity of the people living here is diverse. Canadian shield is the signature work of the natural force. The rolling hills, numerous water bodies, and green lush should need to be preserved for the future.