1. Plate tectonics

2. Tectonic Plates

3. Plate Tectonics Greek – “tektonikos” of a builder
Pieces of the lithosphere that move around
Each plate has a name
Fit together like jigsaw puzzles
Float on top of mantle similar to ice cubes in a bowl of water

4. Continental Drift Alfred Wegener 1900’s
Continents were once a single land mass that drifted apart.
Fossils of the same plants and animals are found on different continents
Called this supercontinent Pangea, Greek for “all Earth”
245 Million years ago
Split again – Laurasia & Gondwana 180 million years ago

5. Evidence of Pangea

6. Sea Floor Spreading

7. Sea Floor Spreading
Mid Ocean Ridges – underwater mountain chains that run through the Earth’s Basins
Magma rises to the surface and solidifies and new crust forms
Older Crust is pushed
farther away from the ridge

8. Why do plates move?

9. Convection currents

10. Convection currents What are they? How do they make plates move?
When mantle rocks near the radioactive core are heated, they become less dense than the cooler, upper mantle rocks. These warmer rocks rise while the cooler rocks sink, creating slow, vertical currents within the mantle (these convection currents move mantle rocks only a few centimeters a year). This movement of warmer and cooler mantle rocks, in turn, creates pockets of circulation within the mantle called convection cells. The circulation of these convection cells could very well be the driving force behind the movement of tectonic plates over the athenosphere.

11. Subduction
What is it?
One plate sinks underneath the other because it is more dense.

12. How Plates Move

13. Convection currents

14. Destructive vs. Constructive forces
Define both of the terms below:
Constructive forces- builds the Earth up
Destructive forces- Breaks the Earth down

15. Destructive or constructive?
type
destructive
constructive
both
Erosion
Weathering
Deposition
Volcano
earthquake

16. Different Types of Boundaries

17. Plate boundaries Transform Plates slide past each other
Earthquakes form

18. Transform Boundary – San Andreas Fault

19. Plate boundaries Divergent Plates divide
In ocean- will be mid-ocean ridges
On land- rift valleys
Why? As plates spread apart, magma rises through the gap and forms new crust

20. Divergent Boundary – Arabian and African Plates
Arabian Plate
Red Sea
African Plate

21. Divergent Boundary – Iceland

22. Divergent Boundary - Oceanic

23. Divergent Boundary - Continental

24. Convergent Boundary – Indian and Eurasian Plates
Indian Plate

25. Convergent Boundary – Oceanic & Continental
&

26. Plate boundaries Convergent Plates collide (go together)
When ocean plates meet continent plates, an ocean trench forms with volcano on the land
Why? Ocean plate is more dense than continental and sinks under it into mantle (subduction)

27. Convergent Boundary – Oceanic & Oceanic
Note – plates are reversed
&

28. Plate boundaries Convergent Plates collide (go together)
When ocean plates meet ocean plates, an ocean trench forms with magma forming islands
Why? The ocean plate that is more dense will sink under the other (subduction)

29. Convergent Boundaries - Continental
&

30. Plate boundaries Convergent Plates collide (go together)
When continent plates meet continent plates,
mountains form
Why? Continental plates buckle up as they push together

31. Plate tectonic animations

32. Additional activities:
Plate tectonics
Volcanoes
Earthquake
Pangaea activity worksheet
Plate boundary prediction worksheet