Lesson 2-6 - Lecture notes 2 PDF

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Module 2: Physical Geography of Canada Lesson 2-6 Soil Classifications in Canada Classification Cryosolic Podzolic Luvisolic Chernozemic Mountain Complex (soil varies by slope and aspect)

Location Territorial North Canadian Shield Southern Ontario Prairie Provinces Cordillera

Cryosolic Soil It is generally found north of the tree line and is the dominant soil in the Arctic Archipelago and around Hudson Bay. It is found where the mean annual temperature is below 0°C and where continuous permafrost is common.

Podzolic Soil It is most commonly found in cool, moist climates (Canadian Shield) and is light grey in colour. It is commonly associated with the boreal forest. Moisture easily percolates downward through this soil due to the large pore spaces.

Luvisolic Soil It is most commonly found in humid continental climates (Southern Ontario) and is most commonly associated with deciduous vegetation. High amounts of organic content are evident due to trees dropping leaves creating a thick organic layer. Warm summers lead to quick decomposition of organic material thus adding to the soil. Organic refers to material that is composed of matter from a once-living organism. Ex: leaf litter, twigs, branches, etc.

Chernozemic Soil It is most commonly found in dry climates where grasslands are located. It is light brown to dark brown with relatively high organic content. Percolation of moisture does not occur as easily as in podzolic soil. The inability of chernozemic soil to absorb moisture quickly is one reason flooding is more of a concern in the prairie provinces.

Chernozemic Soils of the Prairies

This cross-section diagram shows that the size of the grasses increases as we travel from west to east through the chernozemic soil of the prairie provinces. This is because the climate in Alberta is very dry but as we travel eastward into Manitoba, annual precipitation increases.

Palliser’s Triangle This dry area in the western Prairies was named by John Palliser, the leader of a land survey expedition of the western part of British North America for Britain in the 1850s. He declared that it was an area unsuitable for agriculture. Since then, growing wheat and cattle ranching have become the common land uses. Farmers here often require government subsidies to aid in surviving long drought conditions.

Palliser’s Triangle is the driest part of southern Canada. Notice how the largest cities did not develop in the triangle, but instead developed around it.

Drainage Basins Every river has a drainage basin (the area of surrounding land that is drained by that river). Lakes have drainage basins as well, defined as the area of land that drains into that lake.

Mackenzie River Drainage Basin

Great Lakes Drainage Basin

Imagine a raindrop falling onto the yellow-shaded area on the left image. As long as it doesn’t evaporate, then that raindrop will eventually drain into a stream which will eventually drain into the Mackenzie River (the blue line), and then into the Arctic Ocean. All water that falls on a continent eventually drains into the ocean (sea level). For the Great Lakes, any raindrop that falls in the brown-shaded area will eventually drain into one of the Great Lakes, and will then travel through the St. Lawrence River and into the Atlantic Ocean.

Divides Divides form the boundaries of drainage basins. A divide is a ridge of higher land that separates which way rivers flow.

Notice that the divide splits how the streams and rivers flow. On the right image, notice that none of the streams cross the divide (the outer edge of the drainage basin). All of the streams drain into the Grand River and then the river drains into Lake Erie at the town of Dunnville.

Grand River Drainage Basin

If you were to travel on Hwy 401, you would cross the divide just east of Woodstock. In Ontario we don’t often realize when we are crossing a drainage basin divide because the ridges are very subtle.

Continental Divide The Continental Divide is located along the spine of the Rocky Mountains. It forms much of the British Columbia – Alberta border. It separates which ocean the rivers will eventually drain into.

Toward Toward

Atlantic Ocean

Pacific Ocean

We can think of the Continental Divide as the spine of the continent. It is found along the highest elevations of the continent and it splits into which ocean the water drains. The Alberta-B.C. border is very jagged and squiggly because it follows along the Continental Divide.

Major Drainage Basins in Canada

Figure 2.9 Notice that the Quebec-Labrador border also follows along a drainage basin divide.

Drainage Basins as Open Systems Rivers within a drainage basin are in a state of dynamic equilibrium and adapt to changes in the daily inputs and outputs of water within in the drainage basin. Inputs: precipitation, snowmelt Outputs: rivers, evaporation

These images are from 2018 when rapid snowmelt caused the Thames River to flood both on campus (left) and in Harris Park in downtown London (right).

Columbia Ice Field This is the last remaining ice sheet in southern Canada. It straddles the continental divide in Jasper National Park and contains 8 large alpine glaciers. The North Saskatchewan River originates in the Columbia Ice Field; this river flows through Edmonton and Saskatoon.

The Columbia Ice Field is located at the convergence of two major drainage basin divides. Tourists are taken to the ice field on special vehicles (left image) which allows people to walk on a glacier. I have done this…the glacier was much softer than I anticipated. Sand, pebbles, and rocks were mixed in with the glacier.

Glacial Retreat The Athabasca Glacier is the most well-known alpine glacier in the Columbia Ice Field. It is retreating at a rate of 2-3 metres per year. It is the most well-known glacier because it is the one that tourists are allowed to visit and walk upon.

Changes in Arctic Sea Ice In the coming decades, the polar areas are expected to warm faster than any other areas on Earth.

Notice in 1979 the water between the islands in the Arctic Archipelago remained frozen yearround. However, today there is open water between these islands and cruise ships and oil tankers can travel through the passages. The ice in the Arctic Ocean is rapidly melting due to a concept referred to as positive feedback: Ice/snow reflect sunlight. As the ice/snow melt, the resulting water/land absorbs sunlight. This heats up the water/land and encourages nearby ice to melt....