1. Major Geological Events
Caused by
Plate Tectonics

2. Sea-floor spreading
process by which new sea floor forms
Convection Currents
denser rock sinks down and less dense rock is pushed up
Plate Tectonics
theory that states Earth’s outer layer is broken into large, slowly moving pieces

3. Types of Boundaries Divergent   Plates move apart Convergent 
Plates come together
Transform
Plates slide horizontally
past each other

4. Divergent Structures New crust is formed as plates pull apart.
Land features include:
Mid-Ocean Ridges
Ex. - Mid-Atlantic Ridge
Rift Valleys
Ex. - African Rift Valley
Earthquakes

5. Mid–Ocean Ridge (Location of Sea Floor Spreading)

6. Sea Floor Spreading (Mid-Ocean Ridge)
Younger
Older
Older
Divergent Structure

7. Rift Valley Divergent Structure
Divergent Structure

8. Convergent Boundaries
Crust is destroyed and recycled back into the mantle
Three types of convergent collisions
Features include:
Trenches – Mariana Trench
Volcanic Arc (Volcanic Mountains) – Andes mountains
Mountain Ranges – Himalayan Mountains
Earthquakes

9. Subduction Result of convergent boundary
A more dense plate slides under a less dense plate and sinks into the mantle.
Features include:
Oceanic-Oceanic = Trenches
Oceanic-Continental = Mountain Ranges

10. Subduction Examples

11. Oceanic-Oceanic convergence
Convergent Boundary
Oceanic-Oceanic
Land Features – Trench and Island Arc
Oceanic-Oceanic convergence

12. Oceanic-Continental convergence
Convergent Boundary
Oceanic-Continental
Land Features – Trench and Volcanic Arc (Volcanic Mountains)
Oceanic-Continental convergence

13. Continental-Continental convergence
Convergent Boundary
Continental-Continental
Land Features – Folded Mountains
Continental-Continental convergence

14. Mountain Ranges

15. Transform Fault Structures
Crust is neither destroyed nor created
Can occur between two oceanic plates or oceanic-continental plates
Features include:
Earthquakes
Fault line – San Andreas Fault

16. Transform Boundary
Oceanic-Oceanic
Land Feature – Fault Line

17. Transform Boundary San Andreas Fault Line

18. Transform Boundary Continental-Continental Land Features – Fault Line
Aerial view of San Andreas Fault in the Carrizo Plain, self-made, Nov 16, 2007, I. Kluft,

19. Earthquakes – All Boundaries

20. Volcanoes

21. Putting It All Together

22. Plate Boundaries

23. Plate Movement