1. PHYSICAL GEOLOGY OF CANADA

2. Introduction to Plate Tectonics

3.  Some parts of Canada, such as the Canadian Shield, are over 3 billion years old.  The Appalachian Mountains of Atlantic Canada are 200 million years old while the Rocky Mountains are only 65 million years old.

4. Plate Tectonics  The theory of plate tectonics best explains the evolution of the earth’s landforms.

5.  A German scientist named Alfred Wegener first proposed the Theory of Continental Drift in 1912.  200 million years ago all the continents were grouped together in one large land mass called Pangea.

7.  The earth’s crust is divided into 20 plates.

8.  The plates move because they are resting on the partially melted rocks of the asthenosphere.

9.  Slowly flowing convection currents move the plates in various directions.

10. Three Basic Boundaries

12. Converging Plate Boundaries  Two plates moving toward each other  The collision can cause the lithosphere to be pushed up into a mountain range.

13.  Example: The Himalayas formed from India pushing northward into China.

14. Subduction Plate Boundaries  A type of converging plate boundary where one plate is plunged downward under the overriding plate.

15.  When an oceanic plate collides with a continental plate, the lighter ocean plate is subducted underneath the continental plate.

16.  Forms a mountain chain and a deep- sea trench.  Deep & strong earthquakes.

17. Main Convergent Boundaries

18.  The Ring of Fire is a volcano & earthquake zone that encircles the Pacific Ocean.

19. Earthquake and Volcano Data EQ Magnitude less than 5.0 EQ Magnitude 5.0 to 6.9 EQ Magnitude 7.0 and above Volcano

20. Diverging Plate Boundaries:  Two plates are moving away from each other

21.  The Mid-Atlantic Ridge is the spreading center, which separates the North American Plate from the Eurasian Plate and the South American Plate from the Africa Plate.

23.  The MAR was formed by the solidification of magma as the older rock moves aside.

24. Main Divergent Boundaries

25. Transform Plate Boundaries  Two plates are sliding past one another – causes earthquakes

26.  Example: San Andreas Fault has resulted from the North American Plate sliding past the Pacific Plate.

27. ORIGIN OF CANADA’S LANDFORMS  The Canadian Shield is the oldest part of North America.  The plains were formed from the sediments carries off the shield and deposited in the shallow seas that once surrounded it.  200 million years ago the collision of the North American & Eurasian Plates created the Appalachian Mountains.

28.  The Western Cordillera is a relatively new mountain range (only 65 million years old). It was formed when the Pacific Plate was subducted under the North American Plate.  Millions of years of erosion deposited sediments from the mountains into the surrounding seas.  During the Pleistocene ice age (10 000 years ago) the continental ice cap advanced & retreated across Canada several times.

29. QUESTIONS:  page 25, Define “New Words to know”, #1 - 3