Creating Canada’s Landform Regions

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The movement of the earth’s plates, and the resulting folding, faulting, and volcanic activity, have combined with the forces of weathering and erosion to create a variety of landscapes that affect the way we live.

Linking to Tectonics…

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Landforms are the physical structures that make up the appearance of the earth’s crust.

Some examples (but not all..) are: Mountains, Valleys, Plains, Hills, etc.

Think of landforms this way…

If you were a giant and could pick up the earth, you would feel bumps, grooves, flat areas and sharp areas….(You know, hills, valleys, plains, mountains…..)

Landforms were created by different physical

processes, some that build the land up or

add new crust, and some that tear (destroy)

the land down by processes of erosion.

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Dinosaur Provincial

Park, Alberta

So, let’s recap:• Over millions of years, Canada’s

physical landscape has changed.• 300 million years ago, the super

continent of Pangea existed • 200 million years ago the continents

drifted apart creating their modern locations

• Some continents collided and pushed the crust up to create mountains (Himalayas)

• some earthquakes happened where one piece of land shifted and rose up

• volcanoes erupted along fault lines to create volcanic mountains.

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This is not NEWS to you!! 6

Plate Tectonics???

Building Landscape

The three main forces responsible for mountain building are

1) Folding

2) Faulting

3) Volcanism

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Forces That Destroy Landscape

Weathering and Erosion

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FOLDING

When plates move, different kinds of pressure

are emitted, causing different effects to the

physical land.

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Some mountains are formed by horizontal compression (squeezing together) of rock layers as continents come together causing the rock layers to buckle and fold.

See how one plate (right side) is folding because two plates are

colliding.

FAULTING

Again, earthquakes at plate boundaries can

create different landforms.

Faulting occurs when the crust cracks where

two plates meet.

Some mountains are formed by the rising and

tilting of large blocks of the earth’s crust (tilted

or block mountains).

Such movements occur along fractures in the

earth’s crust called faults (faulting occurs)10

FAULTING (cont.)

Faulting often has 2 plates moving apart

creating a valley

OR 2 fault lines can also squeeze a piece of

crust in the middle causing it to pop up (block

mountains)

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VOLCANISM

Volcanoes add lava (rock) to existing

landscape, eventually creating mountains

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Mt. St. Helens before it erupted

http://en.wikipedia.org/wiki/Mount_St._Helens

Mt. St. Helens after it erupted

Check out time lapsed video of Mt. St. Helens growing back!!

Weathering vs. Erosion

Weathering is what breaks the rock into

smaller pieces…

Erosion is the actual removal of the

rock pieces…

…… (think of wiping dirt off a table)

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There are 3 main forces of weathering and/or erosion.

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1. Wind 2. Water 3. Ice

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Wind

Blows small pieces of rock or dirt around; these pieces can hit other rock, further weathering it (sandblaster!!!)

Water

Water in many forms breaks down the landscape. RainWater falling (dripping and waterfalls) Waves

Ice

When water freezes & turns into ice, it expands almost 10 %. (Think about a can of coke that exploded in the freezer.)

Nature’s Freeze/Thaw Cycle When water freezes in a crack in the rock it expands Cycle weakens the rock and eventually causes it to crack and break off (think about pot-holes on the road)