Creating Canada’s Landform Regions 1. 2 The movement of the earth’s plates, and the resulting...
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Transcript of Creating Canada’s Landform Regions 1. 2 The movement of the earth’s plates, and the resulting...
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)