1. Theory of Plate Tectonics (1960) Earth’s lithosphere consists of rigid, but moving masses called tectonic plates

2. Tectonic Plates

3. Lithosphere
Outer shell of Earth that is made of rigid crust and upper mantle
Broken into moving tectonic plates

5. 2 Types of Lithosphere Oceanic Crust Made up of the ocean floor
Continental Crust
Made up of continental landmasses.

6. Oceanic Crust vs. Continental Crust

7. How do the plates move?!
CONVECTION

8. Convection currents
Unequal heating from the Earth’s core causes hotter magma to rise and cooler magma to sink down towards the core and heat up

11. There are 3 main ways that the plates interact.
Plate Boundaries
There are 3 main ways that the plates interact.
Points of interaction are called boundaries

12. 3 Types of Plate Boundaries…

13. Where two plates are moving apart,
1. Divergent Boundaries
Where two plates are moving apart,
magma rises and fills space between plates creating new crust as it cools
CRUST IS GAINED

14. Divergent boundaries

15. 2.Transform Boundaries
Plates horizontally slide past one another

16. 3. Convergent Boundaries
When two plates collide
CRUST IS LOST
There are 3 types….

17. 1. Continental + Oceanic Convergence=
SUBDUCTION ZONE
When an oceanic plate collides with a continental plate
One plate subducts under the other forming a trench

18. SUBDUCTION ZONE

19. 2. Cont. + Cont. Convergence
Two continental plates collide
The plates crumple and uplift
Form folded mountain ranges

20. 2. Cont. + Cont. Convergence

21. 3. Oceanic to Oceanic Convergence
Trenches form as one plate subducts and melts
Magma rises to the surface along the trench and slowly forms an island chain called an ISLAND ARC

22. SUBDUCTION ZONE

24. 1. Divergent boundaries
1. Mid-ocean ridges: Underwater mountain range that winds throughout the Earth’s oceans. It is the 40,000 miles long

26. New Crust Forms Here As Crust is Pulled Apart

27. 2. Rift Valley: When the crust is pulled or ‘rifted’ apart, valleys form with steep walls

28. Transform Boundaries
Earthquakes occur when stress is too great from plates sliding, causing fracture to form in the crust

30. Example: San Andreas Fault

31. Boundary Features

32. 1. Volcanoes

33. Volcanoes
Subduction and its resulting gas chemical reactions, causes hot lava, ash and gas to return to the atmosphere

34. 2. Island Arc

35. Island Arc
Magma rises to the surface along the trench and slowly forms an island

36. 3. Trench
Trench
Subducting Plate

37. Deep depression in the ocean floor caused by subduction

38. 4. (Folded) Mountains
Appalachian Mountains

39. Himalaya Mountains

40. Folded Mountains
As compressional force increases, folded mountains form
Appalachian Mountains

43. Click on Plate Tectonics Activity (with a yellow arrow)
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Click on Plate Tectonics Activity (with a yellow arrow)
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44. Were you right?