Glaciation

1. Glaciation

2. Shaping of the Earth Our planet has NOT always looked the same! • There are many natural processes that have shaped it for thousands of years • It is still changing today!

3. Natural Processes • Some of these natural processes happen quickly • Landslides, volcanoes, and earthquakes • Some of these natural processes happen slowly • Weathering and erosion, tectonic plate movement, and glaciation

4. Natural Processes There are 3 Major NATURAL processes that erode the Earth and its surface

5. Processes that Erode 1) Water

6. Processes that Erode 1) Water 2) Wind

7. Processes that Erode 1) Water 2) Wind 3) Ice

8. Let’s focus on ICE!

9. Glacier Definition • A glacier is a large piece of ice • It moves slowly • It is made of compacted layers of snow • It slowly melts and freezes • It flows depending on gravity and weight

10. Glaciation Definition When we talk about how Glaciers change the Earth, we are talking about GLACIATION

11. How are Glaciers Made? • Even though areas sometimes feel hot, the Earth has a fairly cool climate overall • Especially near the poles, and at high elevations • This is why some snow doesn’t melt when it falls • Instead, more and more piles up • It gets very deep and heavy

12. How are Glaciers Made? • Glaciers can become so heavy and dense that the snow at the bottom turns into ice • Once they are created, gravity causes them to move downhill

13. Two types of glaciers: 1) Alpine Glaciers 2) Continental Glaciers “Alpine” = in a mountain area

14. 1) Alpine Glaciers • Located in mountain regions (areas) • Gravity pulls them downwards • As they move, they scrape away the walls of the valley • Turns them from a V shape, to a U shape http://geology.about.com/library/bl/images/blglacierval.htm http://www.flickr.com/photos/davejglaves/1191311285/

15. 1) Alpine Glaciers • As glaciers move, they leave behind a trail of all the things they picked up • Rocks and sediment • We call these deposits (things left behind) moraines

16. Moraines • We live right near a big moraine called the “Oak Ridges Moraine” • This moraine has great soil for growing crops!

17. 2) Continental Glaciers • Cover large areas of land • Moves because it is SO heavy • It spreads outwards from the center. We call this the Zone of Accumulation • Smoothes (flattens) the landscape by eroding highpoints and filling in lower parts http://www.swisseduc.ch/glaciers/glossary/icons/glacier-advance.jpg

18. 2) Continental Glaciers • These glaciers can also make lakesdeeper and wider • The Great Lakes were formed this way • The Canadian ShieldCanadian Shield was also formed this way • Today, this type of glacier only exists in Greenland and Antarctica. http://www.novaspace.com/POSTERS/PHOTO/GreatLakes.jpeg

19. ICE AGE! • There have been a few times in history when the climate of the earth is cooler than usual • Creates many glaciers • This causes a glacial period, or an “ice age”

20. ICE AGE! • The most recent Ice Age ended 6,000 years ago • It had lasted for almost 100,000 years • Canada was covered by ice sheets which were 4 km thick Fact: An ice sheet is more than 50,000 km²

21. The Columbia Icefield http://www-mtl.mit.edu/~fana/Alaska_trip/Icefield_pwky/columbia_01_medium.jpg

22. The Columbia Icefield http://www-mtl.mit.edu/~fana/Alaska_trip/Icefield_pwky/columbia_01_medium.jpg

23. The Columbia Icefield http://www-mtl.mit.edu/~fana/Alaska_trip/Icefield_pwky/columbia_01_medium.jpg

24. The Columbia Icefield http://www-mtl.mit.edu/~fana/Alaska_trip/Icefield_pwky/columbia_01_medium.jpg

25. Questions • How are glaciers formed? • How do glaciers move? • What are the main differences between an Alpine and Continental Glacier? • Where can we find glaciers today? • Which areas of Canada were shaped by Glaciation? • How were the Great Lakes formed?