1. 3.3 Plates Move Apart Learn about: Different types of plate boundaries
What happens when plates move apart or push together?
How does plate movement effect the earth?

2. Plate Boundaries There are three kinds of plate boundaries
Divergent
Convergent
Transform
Both the kind of boundary and the kind of plate affects how plates interact

3. introduction 12.43

4. Transform Faults
Transform faults occur along divergent oceanic and continental plate boundaries
Plates slide past each other building up tension until the tension is released during an earthquake

5. San Andreas Fault
The San Andreas fault is a surface fault line going through San Francisco
In 1906 an Earthquake hit San Francisco setting breaking gas and water lines and causing fires that could not be stopped

6. Types of Convergent Boundaries
Continental – Continental Collision
Continental – Oceanic Subduction
Oceanic – Oceanic Convergent

7. convergent plates and mantle 2.36

8. Continental – Oceanic Convergent Boundary
Occurs when ocean crust and continental crust are pushed together
What happens there? (Subduction Zone)
Subduction – one plate is pushed under another.
Which Plate always goes under? And why?

10. Oceanic-Oceanic Convergence
When oceanic plates collide a subduction zone occurs
One plate goes under the other deep beneath the ocean floor
(creating a deep ocean trench.)

11. Island Arcs- can form when oceanic plates converge

12. Japan
Japan is part of an Island Arc formed by oceanic-oceanic convergence

13. (see next slide for an illustration)
Subduction Zone?
What kinds of landforms are created at a Subduction Zone?
Deep Ocean Trenches
Volcanoes (after a long period of time.)
Coastal Mountain Ranges (Parallel to the Coast.)
(see next slide for an illustration)

14. Continental-Continental Convergence
When two continental crusts collide the pressure builds up and they form Mountains
Since both plates are approximately equal density neither subducts and no volcanoes are formed

16. Types of Divergent Boundaries (What happens there?)
Oceanic – Oceanic Divergence
Mid-Ocean Ridges
Rift Valleys
Continental – Continental Divergence

17. Divergent Boundary
Most divergent Boundaries occur on the ocean sea floor.

18. Divergent boundary animation
interactive map

19. Continent-Continent Divergence Boundary
Continental plates diverge in the same way as Oceanic plates
Cliffs and ridges are more easily visible in continental divergence

20. Continental- Continental divergent Boundary
Same as Oceanic – Oceanic Boundaries rift vallies will occur.
What is different?
In this case, rift valley’s happen on land.
Two piece of land are pulled apart, revealing magma. (it will cool and harden)
Creating what is called a continental rift valley (it could fill with water, making a lake.)

21. Rift Valleys

22. East African Rift Valley
The East African Rift Valley formed when a three way split almost tore Africa apart
Example of a Continental rift valley.

23. East African Valley (On land Rift Valley)

24. Oceanic-Oceanic Divergence
This is where two oceanic plates were diverging forming new crust

25. Oceanic-Oceanic Divergence (Continued)
This is where oceanic plates are being ripped apart magma comes up from deep within the earth’s crust and forms pillow basalts and under water vents

26. The Mid Atlantic Ridge
The Mid Atlantic Ridge is an example of oceanic-oceanic divergence
Over millions of years the continents have moved enough to create an ocean
The ridge also contains the longest mountain chain in the world
(6214 miles long)
(15 miles wide)
(6 miles deep)

27. Mid- Atlantic Ridge (continued)

28. Review Oceanic-Oceanic Divergent Boundaries
With your neighbor, review what happens at Divergent Oceanic-Oceanic Boundaries
Remember to put these concepts into your own words.
How can you best remember the information?
(You have 2 minutes)

29. Review the difference! What is the difference between?
Oceanic – Oceanic divergence and
Continental – Contiental divergance
(you have 1 minute)

30. Hot Spots Another type of tectonic activity are areas called hot spots
A hot spot is where magma rises to the earths crust melting the land and forming a line of volcanoes as the earth’s crust moves past it

31. Hot Spots

32. interactive map

33. Hawaii In oceans hot spots form Island chains
Since the hot spot is under mafic rocks the lava flows smoothly down the mountain creating shield volcanoes like Hawaii

34. Yellowstone National Park
Hotspots below continents are highly explosive and form craters called calderas
The force required for Felsic rock is so great the eruption vaporizes the land and sends ash over large parts of continents

36. To sum it up
all three types
Plate rap
Mr Parr

37. Plates in action and Homework
to help you study
Homework - Watch the following video and study types of plate tectonics
You can also read B 3.3 and 3.4 to help you study