1. Plate Tectonics

2. Global Plate Boundaries
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4. Plate Boundaries There are 3 main plate boundaries:
1) Convergent Boundary
2) Divergent Boundary
3) Transform Boundary

5. Types of Plate Boundaries

6. Draw With Me 

7. 1. Convergent Boundaries
Occurs when 2 plates collide.
Oceanic plate is denser (3.2 g/cm3), faster and thinner - it is usually forced under the continental plate (2.8 g/cm3).

8. The rock in the Oceanic plate melts as the plate sinks
The rock in the Oceanic plate melts as the plate sinks. The melted rock rises up causing volcanic eruptions.
The area of convergence is called a SUBDUCTION ZONE.
When two continental plates collide:
They are the same density.
This causes the plates to fold and bend (mountain building) as well as earthquakes.

10. Convergent Boundary Plates move toward each other
Oceanic crust destroyed
Ocean trench
Volcanic arc

11. Example of a Convergent Plate Boundary
South America:
Oceanic Nazca Plate is colliding into the South America plate.
Producing the Andes Mountains (volcanoes along the mountain crest) and formed a deep trench off the coast in the Pacific Ocean.

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14. Convergent Boundaries

15. Let’s do some drawing!

16. Divergent Plate Boundaries
Plates are being pulled apart by convection currents in the mantle.
As the plates separate along the boundary, they crack into faults and blocks. Magma from the mantle rises through the cracks. This cools and new crust is formed along the boundary.
Earthquakes occur along the faults, and volcanoes form where the magma reaches the surface.

17. Mid Atlantic Ridge Mid-Atlantic Ridge is a Divergent Plate Boundary.
Over km long.
Average height of volcanoes - 3 km.

19. Age of Ocean Floor

21. Example of a Divergent Plate Boundary
The Process of Rifting

22. Divergent Boundary Rift valley Plates move apart Mid-ocean ridge
New ocean floor created

23. Sea Floor Diagram
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24. Generation of a Divergent Boundary

25. Types of Spreading Centers

26. Sea Floor Spreading Mid-ocean ridge – spreading center
Subduction zones – oceanic trench site of crust destruction

27. Earthquakes As Evidence
Earthquake activity mirrors tectonic plate boundaries.
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28. Global Distribution of Earthquakes

29. Transform Boundary Places where plates slide past each other sideway.
Transform boundaries are not marked by spectacular surface features, but their sliding motion causes lots of earthquakes.
The slice of California to the west of the fault is slowly moving north relative to the rest of California.

30. The Problems of Haiti…

33. Interactive Plate Tectonic Map
Go to the following site and complete the activity!

37. Earth’s Magnetic Field

39. HOT SPOT VOLCANOES
Animation

40. Examples of Plate Boundaries

41. Transform Boundary Features
Oceanic Transform Fault – ocean floor only
Continental Transform Fault – cuts across continent
All transform faults occur between mid-ocean ridge segments.

43. Global Hotspot Locations

44. Hawaiian Island – Emperor Seamount Nematath

45. Plate Tectonics Features
Seamounts
Rounded tops
Tablemounts or guyots
Flattened tops
Subsidence of flanks of mid-ocean ridge
Wave erosion may flatten seamount

47. Detecting Plate Motion with Satellites

48. World Map 50 million Years in Future

49. Coral Reef Development
Fringing reefs – develop along margin of landmass
Barrier reefs – separated from landmass by lagoon
Atolls – reefs continue to grow after volcanoes are submerged

50. Coral Reef Development