1. The Dynamic Earth: PLATE TECTONICS

2. Types of Plate Boundaries
EQ:
How does plate tectonics shape the earth’s surface?

3. Types of Plate Boundaries
There are approximately 20 plates found on the Earth’s crust.

4. These plates are moving in relation to one another in a process known as PLATE TECTONICS.

5. Review
What is the lithosphere?
What are the 2 types of crust?

6. Convergent Boundaries
A convergent boundary is a boundary between two lithosphere plates that are moving toward each other, or converging.

7. Convergent Boundaries
Earth has 2 types of crust on it’s surface; Continental and Oceanic Crust.
There are 3 different types of convergent boundaries and processes involved depending on the types of crust involved.
These processes are known as either Subduction or Collison.

8. Convergent: Ocean to Ocean 2 oceanic plate colliding!
Volcanic Island Arcs are a feature formed at these boundaries.
Current Example: the islands of Hawaii

9. Convergent: Continent to Continent 2 Continental plates are colliding!
If two plates each carrying continents collide, they become welded into a single, larger continent.

10. Convergent: Continent to Continent
Feature: The collision causes the crust at the boundary to be pushed upward into a mountain range.

11. Current Example: The world’s tallest mountains are known as the Himalayas.

12. Convergent: Continent to Ocean 1 Oceanic plate and 1 Continental plate collide.
When an oceanic plate collides with a continental plate, the oceanic plate sinks under the continental plate.

13. This is because the oceanic plate is made of basalt which is more dense than the granite composed continental crust.

14. Convergent: Ocean to Continent
When a continental plate and an oceanic plate collide common features include:
volcanoes along the coast line
deep-sea trenches

15. Convergent: Ocean to Continent
Current Examples of volcanoes: Mt. St. Helens, Mount Katmai, Mount Pinatubo, Montserrat, Mount Pelee

16. Divergent Boundaries
A divergent boundary is a boundary between two lithosphere plates that are moving apart.
They are sometimes called spreading centers.

17. Divergent Boundaries: Mid Ocean Ridges
In a process called sea floor spreading, molten rock forces its way upward through cracks, or rifts. The molten rock hardens into new oceanic crust.

18. Divergent Boundaries
Hydrothermal vents and the mid-ocean ridge are found at divergent boundaries.

19. The Great Rift Valley in East Africa
Divergent Boundaries
Examples:
Mid- Atlantic Ridge
Great Rift Valley
The Great Rift Valley in East Africa

20. Transform Boundaries

21. Transform Boundaries
A transform boundary is a boundary between two plates that are sliding past one another.
Current Example: San Andreas Fault- moving about 5 cm/year.

22. The main feature of transform boundaries are…
EARTHQUAKES
Observe animations of processes that occur along plate boundaries.

23. Plate Tectonics Map - Plate Boundary Map