1. Plate Tectonics
the movement of Earth

2. Plate Tectonics
Tectonic plates: pieces of the Earth’s crust & upper mantle
Plate boundaries: places where plates meet

3. Plate Tectonics
Movement of plates creates forces that affect Earth’s surface at the plate boundaries and causes them to move.
Plates move in 3 ways:
1. slide past each other
2. move apart (divergent)
3. collide (convergent)

4. Transform Fault Boundaries
Faults form when plates slide past each other
A fault is a large crack in rocks that can break
EARTHQUAKES can happen along fault lines

6. San Andreas Fault, CA

7. Divergent Plates
Plates move apart b/c of pulling forces (tension) that act in opposite directions.
New crust forms in the gaps where plates pull apart.
Form mid ocean ridges (in oceans), and rift valleys (on continents)

8. Divergent Boundaries
Boundary between two plates that are moving apart or rifting
 
RIFTING causes SEAFLOOR SPREADING

9. Divergent Plate Movement: Seafloor Spreading
the movement of two oceanic plates away from each other (at a divergent plate boundary), which results in the formation of new oceanic crust (from magma that comes from within the Earth's mantle) along a mid-ocean ridge.
Ocean floor spreading was first suggested by Harry Hess and Robert Dietz in the 1960's.

11. Features of Divergent Boundaries
Mid-ocean ridges

12. Features of Divergent Boundaries
Rift valleys
Quilotoa, Ecuador

13. Features of Divergent Boundaries
Fissure volcanoes
Hawaii, USA

14. Mid-Atlantic Ridge
a divergent tectonic plate boundary located along the floor of the Atlantic Ocean
the longest mountain range in the world.
separates the Eurasian Plate and North American Plate and the African Plate from the South American Plate

18. Divergent Plates
Bridge between continents in Reykjanes peninsula, southwest Iceland across the Alfagja rift valley, the boundary of the Eurasian and North American continental tectonic plates.

19. Oceanic Ridges

20. Convergent Plates
When plates collide, different things can happen (depends on the density of the plates involved).
There can be: continental-continental collisions, oceanic-oceanic collisions & continental-oceanic collisions

21. Continental-Continental Collisions
Forms a mountain range

23. Oceanic-Continental Collisions
Forms a trench and volcanic arc

24. Andes Mountains, South America

25. Oceanic-Oceanic Collisions
Forms an island arc

26. Aleutian Islands, Alaska

29. Subduction Zones When one plate plate sinks underneath another plate.
The denser plate sinks underneath & into the mantle.

30. Fold
When rocks bend due to force.

31. Fold: When rocks bend
Anticline (Upward)
Syncline (Downward)

32. Anticline

33. Syncline

34. Convection the circulation of heat
A theory explaining why the plates move.
Theory says plates move b/c the mantle material is being circulated b/c of the difference in densities in the mantle.