Ontario Physical Geography

Ontario Physical Geography

Jeff Walters, March 29th 2017

Ontario is divided into three main geological areas. The Canadian shield covers the northwestern part and is thinly populated because of its cold climate and infertile soil. The northeastern part includes the barely populated Hudson’s Bay Lowland which is swampy and sparsely forested. The third is the temperate St. Lawrence-Great Lakes Lowlands, the most populated region in Canada. Ontario contains no mountainous areas but has many uplands and lowlands.

1. Canadian Shield

The Canadian Shield is a Precambrian shield that is covered with the Boreal Forest. It is a vastly exposed area of igneous rock and highly metamorphic rock that is tectonically active while only barely and is dominated by granite. The Canadian Shield formed 2.5 billion years ago due to the shifting Archean plates and volcanic activity spewing lava which solidified igneous rock. Once stretching to Texas, the Canadian shield may have been the largest mountain range in the world. It has since eroded from mountains to rolling hills due to glacial impact, the seasonal freezing and melting of ice and wind erosion. The shield is full of deposits of gold, silver, copper and iron. Thousands of small lakes are dotted across the Canadian shield due to the retreat of the last ice age. These low lying wetlands occur closer to water table. These swamps and bogs are low in nutrients are are highly acidic. The Canadian Shield is dominated by the boreal forest ecosystem. Common coniferous trees include white and black spruce, jack, red, white and eastern white pine balsam fir, tamarack,  eastern hemlock and eastern red cedar. Deciduous trees include red and mountain maple, white and paper birch, trembling aspen black ash and balsam poplar. A wide range of wildlife calls the Canadian Shield home. Lakes and rivers in the south house a variety of fish species including trout burbot and northern pike In addition to fish, lakes are often spotted with a mix of waterfowl including wood ducks Canada geese and American black ducks. Other birds include boreal owls, great horned owls, blue jays and white-throated sparrows while mammals include caribou, deer, wolves, lynx, beaver and moose.

    2. Niagara Escarpment

The Niagara Escarpment is the longest escarpment in the world ranging 725 km covering upstate New York, southern Ontario and the states of Michigan and Wisconsin compromising fossil rich sedimentary rock. An escarpment is a steep slope or long cliff that forms as an effect of faulting or erosion and separates two relatively level areas of differing elevations. The Niagara Falls is the gem of the scarp attracting many tourists every year. The scarp came into existence around 450 million years ago as a tropical sea. The world was covered in a warm shallow sea where the depression layered the groundwork for the escarpment. At different periods the escarpment would dry and then refill because of drastic changes in climate over millions of years. However adaptable life forms became more complex to adapt to these changes making it an excellent spot for early more complex life forms. The escarpment consists mainly of magnesium and limestone. The progressive action of glaciers, water flows and the elements caused the more resilient dolostone to weather at different rates than the shale, resulting in the very dramatic land forms including sea stacks, karst formation caves, deep valleys, waterfalls and rugged hills. The Niagara Escarpment is perfect for vineyards because of its rainfall and climate.

    3. Great Lakes

The five largest freshwater lakes in the world make up the Great Lakes: the largest Superior, the one with the most shoreline Huron, Ontario where the city of Toronto and Kingston are located, the Michigan located entirely within the state of Michigan, and the smallest, shallowest and smallest by volume Erie named after the Aboriginal tribe that once inhabited its shore.The Manitoulin is the largest freshwater island in the world. The Great Lakes occupy low bedrock depressions after glaciers melted around 14 000 years ago. Many waterways eroded connected all great lakes and were used since the first fur traders. The lakes are freshwater because they are fed by rivers which are fed by rainfall. The lakes freezes at different rates: Ontario freezes by 25 percent as where Erie will freeze by 90%. Lake Superior has the highest elevation and greatest of all features where lake Ontario is the lowest and smallest of the Great lakes.

References

All Ontario

Northern Ontario Travel

Canadian Encyclopedia

Bruce Trail Conservancy  

Ontario Woodlot Association

Giants Rib

Environment Canada