Creating Canada’s Landform Regions

Linking to Tectonics… 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.

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…..)

Dinosaur Provincial Park, Alberta 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.

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.

Plate Tectonics??? This is not NEWS to you!!

Building Landscape The three main forces responsible for mountain building are 1) Folding 2) Faulting 3) Volcanism

Forces That Destroy Landscape Weathering and Erosion

FOLDING When plates move, different kinds of pressure are emitted, causing different effects to the physical land. 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)

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)

Volcanoes add lava (rock) to existing VOLCANISM Volcanoes add lava (rock) to existing landscape, eventually creating mountains Check out time lapsed video of Mt. St. Helens growing back!! Mt. St. Helens after it erupted Mt. St. Helens before it erupted http://en.wikipedia.org/wiki/Mount_St._Helens

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)

There are 3 main forces of weathering and/or erosion. 1. Wind 2. Water 3. Ice

When water freezes & turns into ice, it expands almost 10 %. Wind Blows small pieces of rock or dirt around; these pieces can hit other rock, further weathering it (sandblaster!!!) 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) Water Water in many forms breaks down the landscape. Rain Water falling (dripping and waterfalls) Waves