Landforms, Geology and Human Activities - Making Connections Issues in Canadian Geography(3rd Edition) 

Why do cities sprawl over the best farmland?

• The government published maps in the late 1960s rating the quality of Canada’s land for farming.
• <!--[if !vml]--><!--[endif]-->Excellent farmland is very rare, only 0.5% of Canada’s land(Class 1).
• Good farmland(Class 2 and 3) makes up only 4.5% of Canada’s land.
• The extent of the land on 2006 report predicted would become urbanized by 2031, and most of it has already been built on.

Patterns and Processes

• The four aspects of geography that affect where people live and work in Canada are landforms, climate, natural vegetation, and soils.

Landform Processes

• Coastal British Colombia has the mildest climate in Canada.
• Vancouverites can choose among snowboarding, golf, or sailing – all in the same day.
• One of the effects of Vancouver’s popularity for Canadian and foreign migrants is that an average house costs almost $1 million. Vancouver also tends to face devastating natural hazards, such as earthquakes and tsunamis.
• Tsunami is a set of large ocean waves caused by an earthquake or other powerful disturbance under the sea. A tsunami can cause great destruction when it reaches land.

Drop, Cover, and Hold On!

• Small earthquakes are part of life in coastal British Colombia, but people were shocked when scientists discovered that a massive earthquake with a magnitude estimated between 8.7 and 9.2 had occurred in 1700 under the ocean near Vancouver Island.
• A magnitude 9.0 quake does not have 50% more power than a magnitude 6.0 quake and remember that 6.0 earthquake is still strong enough to damage buildings and kill people. Which makes a 9.0 quake is more than 30,000 times as powerful as a 6.0 quake.
• Earthquakes as strong as that area usually rare but one of them hit Japan in 2011. That earthquake also caused a tsunami and killed about 16,000 people. It caused 10s of Billions of dollars of damage.
• Research showed that magnitude 9.0 quakes occur roughly around every 300 – 800 years.

Forces That Shape Earth

• The earthquake risk in British Columbia, along with the landforms that we see in all parts of Canada, are the result of interplay of a number of powerful natural processes.
• Some processes build up land while others wear it down.
• When the build-up processes are more powerful, the land gets higher. When most wearing down processes are more powerful, the land gets lower.
• To understand the interplay and power of these forces, you must remember that the time spans involved are far beyond anything related to human experience.

Plate Tectonics

• The theory of plate tectonics says that the Earth’s outer shell is made up of individual plates that move, causing earthquakes, volcanoes, mountains, and the formation and destruction of areas of the crust.
• The theory plate tectonics explains why we have high mountain ranges, majestic plains, and the deepest parts of the ocean.
• The Earth’s crust may seem solid and unyielding, but the plate tectonics tells us that the crust is actually floating on molten rocks inside the Earth.
• The crust is also not a single piece, it’s made up of many pieces called the plates.
• There are seven major plates, eight secondary plates, and more than 60 minor plates.
• The movement of Earth’s plates had shaped Canada in many ways, by the mountain chains on the east and west coast grew as a result of plates colliding. They also played a role in the formation of Canada’s fossil fuels. Oil, gas and coal formed when Canada’s land mass was located in a warmer, tropical climate.
• Time and data on plate direction and speed will tell us.

Types of Plate Movement

• Plates are not joined together but are only touching. They move because the molten rock below them moves. There are three possible directions of movement.
• Divergent: Which is when two plates move apart, and this mostly happens along a mid-ocean ridge, but it does happen on land too. When this happens, the plates get larger. New areas of the Earth’s crust are constantly being created in the way along 70,000 kms of mid-ocean ridges. Most of the world’s volcanoes occur along divergent plate boundaries.
• Convergent: Which is when two plates move towards each other and there are two types of convergence.
• One is when the continental plate meets oceanic plate. This is when the rocks that make up deep-ocean plates are denser than those that make up continental plates. However, because of this, the heavier oceanic plate slides underneath a continental plate. This process is called subduction. The crust that goes under is recycled by subduction, and this melting crust balances the new crust forming at a divergent plate boundary.
• Subduction happens pretty smoothly when the oceanic plate moves slowly and continuously under the continental plate, many earthquakes that cause no damage arise. 
• However, in some places, the plates don’t move. The plates push against each other, and the tension builds up for centuries. Eventually the tension is released in a few seconds. The result can be a catastrophic 8.0 to 9.0+ quake. This is the situation that concerns officials in British Columbia, since they know the plates there have been locked since 1700.
• Most of history’s most devastating earthquakes, along with tsunamis, happen due to this. This is including the 1700 earthquake(9.2), the Indian Ocean earthquake and tsunami(9.0), and the 2011 Japan earthquake and tsunami(9.0). In the Indian Ocean earthquake, over 275 000 people died in 11 countries. People were killed by tsunami as far away as Africa, nearly 5000 kilometers from the centre of the quake.
• The second is when continental plate meets continental plate. This is when two continental plates run into each other, massive layers of rock are folded, broken, and forced upward by the immense pressures of the collision. This process created many of the world’s most important mountain ranges.
• The Himalayas(the Mount Everest) began forming when the Indian plate collided with the Eurasian plate. This process started about 55 million years ago and continues today as Mount Everest rises higher and higher above sea level.
• Transform: Which is when along a transform plate boundary (a.k.a a conservative boundary), plates are made neither larger nor smaller. In these locations, the plates move parallel, but opposite, directions.
• <!--[if !vml]--><!--[endif]--><!--[if !vml]--><!--[endif]--><!--[if !vml]--><!--[endif]--><!--[if !vml]--><!--[endif]-->Similar to subduction, this happens smoothly with small earthquakes. But sometimes, the plates lock up for many years and release lots of energy at once, creating an earthquake. These earthquakes are not very severe than the ones that happen due to subduction. Major quakes at transform boundaries are generally in the intensity range of 5.5 to 7.5.
• The Atlantic Ocean grows 1.5 inches wider every year. That's because the tectonic plates undergirding the Americas are separating from those beneath Europe and Africa.

Rock Cycle

•  A. Igneous rocks form when magma or lava cools. We are familiar with this process in films about spectacular volcanic eruptions, but most cooling happens out of sight, either at the bottom or the ocean or inside Earth’s crust.
• You can tell where an igneous rock cooled by the structure of its crystals. Granite formed from magma that cooled very slowly deep inside the Earth, giving time for large crystals to form.
• Igneous rocks formed from molten rock called lava that cools on the surface are called extrusive rocks. These usually have tiny crystals that are barely visible to the naked eye.
• An example of extrusive rocks is called obsidian. It is blown out of a volcano and cools almost instantly. Crystals don’t have time to form, so the rock looks like black glass.
• B. Weathering, erosion, and deposition are related processes that break down all types of rock into small particles and then move the particles to a new location.
• Weathering is the process that breaks down rocks by water, wind, chemicals, and living things. For example, they can be broken by water freezing and thawing in cracks.
• Erosion is the process of moving the broken-up pieces of rock. For example, rivers move rock and soil particles.
• Deposition is the process of the eroded materials building up in a new location. An example of this is the creation of a delta in the sea at the mouth of the river.
• C. Sedimentary rocks are created after millions of years of compaction and cementation of loose sediments. Compaction happens as loose sediments become tightly packed from drying or the weight of more layers of sediments on top.
• Eventually the sediments become cemented together by minerals deposited between them. The type of sedimentary rock that forms depend on the type of sediment. For example, shale is made up of fine silt and clay particles, and sandstone is made up of sand.
• Not all sedimentary rocks come from eroded sediments. Limestone is formed from the shells of tiny marine animals.
• The most important location for the formation of sedimentary rocks is in the ocean next to the continents, three things can typically happen to this sedimentary rock on the bottom of the ocean.
• The first thing is that the rock layers just sit on the bottom of the ocean. In many places of the world, sedimentary rocks on the seabed contain deposits of crude oil and natural gas. These deposits are critical sources of the world’s energy supply. Examples include Canada’s Atlantic Coast, the Gulf of Mexico, the North Sea, and the Persian Gulf.
• The second possibility is that the sedimentary rocks become the “bumper” when two continental plates collide. Canada’s Rocky Mountains (and Mount Everest) are composed of rocks that formed in the sea and were folded and forced up by the plates colliding. Because of this, it is common to see fossils of sea creatures thousands of meters above sea level.
• The third possibility is that tectonic forces lift layers of sedimentary rocks out of the sea while keeping them more or less horizontal. The result is the creation of plains, on which most of the world’s people live. If you live in Ontario, south of the Canadian Shield, the rock beneath you was lifted from the sea in this way.
• Some sedimentary rocks contain deposits of fossil fuels (oil, natural gas, and coal) and are the geologic base of most agricultural regions.
• Aside from these two benefits, the economic importance of sedimentary rocks is often underestimated.
• D. Metamorphic rocks are changed version of igneous, sedimentary, and other metamorphic rocks.
• The changes occur when the rocks are exposed to great amounts of heat and pressure, such as when molten rock intrudes into existing rock layers.
• <!--[if !vml]--><!--[endif]-->Metamorphic versions of sedimentary rock are much harder that the original.
• Slate changes into slate, for example, limestone becomes marble.
• <!--[if !vml]--><!--[endif]-->Metamorphosis means “change form.”
• Metamorphism in igneous rocks is hugely important in the creation of mineral deposits. The great hear and pressure involved can cause minerals to concentrate in relatively small areas. Sometimes, the concentrations of iron ore, gold, nickel, and other minerals are rich enough to make mining worthwhile
• Many Irish Singing Men -> Magma, igneous, sedimentary, metamorphic.

Glaciation

• Massive glaciers cover Antarctic, Greenland, and some mountainous areas.
• The process of ice advancing and covering large areas of land are called glaciation. 
• Glaciation is much less powerful force than plate tectonics, it is still fundamentally important to the creation of the Canadian landforms we seen.
• The reason behind this is that glaciation ended only “one minute ago” in our geological year. In geologic terms, there has been no time for the effects of glaciation to be wiped away by other landform processes.
• Glaciers advanced across Canada four sperate times in the last 2.5 million years. After each advance, there was a retreat as the glaciers melted.
• Assuming you are in Canada, the place where you are sitting right now was covered by as much as three kilometers of ice only 15 000 years ago. One small part of Canada was not glaciated which was part of Yukon.
• The first three glacial advances are not important in Canada today because the fourth one wiped away evidence of them. Geographers in North America call the fourth glacial advance the Wisconsin glaciation because the ice advanced as far south as the American state.
• Glaciers remain in a few mountainous areas of Canada. Western Canada has remnants of the Cordilleran ice sheet, and glaciers still exist in the extreme north on Ellesmere and Axel Heiberg Islands.
• Some Earth scientists think that glaciation may not be over. They suggest that we are only in the interglacial period between the fourth and a possible fifth glacial advance. However, there is no immediate threat- another advance might not happen for 100 000 years or more. Climate change resulting from human activities is a much more immediate threat.

Glaciation and Canada’s Landforms

• Effects of glaciation is not as often because when we look at the land, we see prosperous farming area, a great city, a gravel pit, or an attractive, rugged holiday destination.
• Glacial effects fall into two broad categories, erosional and depositional.

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Erosional Effects

• Glaciers acted as giant earth-moving machines by scraping away the soil and rocks that covered much of Canada. The result is that much of the country has little or no soil today. While most of this eroded land is far north and away from population centers, you can find some as far south as a line from the southern tip of Georgian Bay to Kingston.
• Glaciers also completely changed the drainage patterns of rivers, streams, and lakes. In particular, lakes and rivers that had existed in low areas of loose earth materials were destroyed. New lakes formed in rock basins that filled with water as the glaciers melted away. When this happens, northern Canada ends up having more lakes than it’s possible to count. This is mostly because you can’t really identify the small water bodies.

Depositional Effects

• Deposition happens because of glaciation and falls among two categories, eroded materials deposited directly by ice and those deposited by massive amounts of meltwater.
• Deposition by ice: Materials that are deposited directly by ice are not sorted by size and these unsorted materials are a mixture of loose sediments and rocks of all sizes, called till.
• A common feature formed by deposition is a till plain. Till plains are featureless, with some small hills and valleys. They are formed from rock and sediment released from the glaciers as they melt.
• Another common feature formed directly by ice is a moraine. Moraines are deposits of till that form at the edges (nose and/or sides) of a glacier. The Oak Ridges Moraine, which extends from the Orangeville area to north of Trenton, is an excellent example of the rolling hills and small lakes typical of a moraine.
• Deposition by water: Which is when you start with a huge amount of ice and it warms, either in the summer or as a glacier is melting, you would get an immense amount of meltwater.
• Meltwater moves glacial debris as any river would, but on a much more massive scale. Fast-moving water can move heavy particle like gravel and rocks. As the water slows, it deposits these particles based on weight. First the rocks drop out, then the gravel, and then the sand. The result is that we see materials that have been sorted by size.
• Meltwater rivers flow into meltwater lakes. In these lakes, where there is very little movement of the water, the lightest materials, silt and clay particles- are deposited. Glacial lakes were much larger than today’s lakes(even the Great Lakes), so glacial lake deposits are a common feature in many parts of Ontario and Southern Prairies. These areas tend to be very flat, have deep, rich soils, and are often prime farmland.