2. Forces within Earth’s Crust By: Brianna Shields February 2, 2005

3. DO NOW 1. Which chemical is responsible for creating ozone depletion? 2. Which mineral property is the most reliable for identifying a mineral? 3. Which process carries broken down rock to new locations?

4. GOAL To explain the theory of plate tectonics and to relate it to areas of volcanic and earthquake activity To be aware of the constructive and destructive forces constantly acting upon the earth’s crust

5. Theory of Plate Tectonics Theory of plate tectonics 1. Earth is made of shifting plates beneath oceans and continents Pulling apart Moving sideways Smashing together

6. Earth’s Lithospheric Plates

7. Theory of Plate Tectonics Theory of plate tectonics 2. Earth once had one supercontinent= Pangaea EVIDENCE? Fossils Rock deposits Jigsaw puzzle continents

8. Continental Drift

9. Theory of Plate Tectonics Theory of plate tectonics 3. Earthquakes & volcanoes occur at the plate boundaries Most active plate= pacific plate = “RING OF FIRE””

10. Ring of Fire

11. 9 Lithospheric Plates Eurasian Indo-Australian Antarctic Pacific North American Caribbean South American African Nazca

12. 9 Lithospheric Plates

13. Plate Movement Why are the earth’s plates moving ? Convection Currents- cycling of magma in the mantle beneath the plates Hot rises, cold sinks

14. Tectonic Plate Boundaries 1. Convection currents Magma cycles

15. Tectonic Plate Boundaries 2. Ocean floor Crust, plates

16. Tectonic Plate Boundaries 3. MantleLayer beneath crust, with convection currents

17. Tectonic Plate Boundaries 4. Midocean ridge Lip of hardened rock at plate boundaries

18. Tectonic Plate Boundaries 5. TrenchArea where one plate is subducted beneath another

19. Tectonic Plate Boundaries 6. Subductio n Where ocean floor is plunging down into mantle beneath one of the plates

20. Tectonic Plate Boundaries 7. Ocean floor spreading Where new ocean floor is being made as magma rises up and hardens

21. Tectonic Plate Boundaries 8. Divergent boundaries Plates pulling apart (aka= seafloor spreading)

22. Tectonic Plate Boundaries 9. Convergen t boundaries Plates are meeting (one is subducting) Creates mountains

23. Tectonic Plate Boundaries 10. Strike slip/ transform boundaries Plates are sliding horizontally past eachother Creates earthquakes

24. Movements within the Earth Forces within earth’s crust 1. Fracture- crack in a rock

25. Movements within the Earth Forces within earth’s crust 2. Fault- crack in crust along which rocks move

26. Movements within the Earth Forces within earth’s crust C. Fault Mountains - middle rock between 2 faults, rises

27. Movements within the Earth Forces within earth’s crust D. Fault Valleys -middle rock between 2 faults drops

28. Movements within the Earth Forces within earth’s crust 3. Folding- rock bends A. Anticline- upward fold (mountain)

29. Movements within the Earth Forces within earth’s crust 3. Folding- rock bends B. Syncline- downward fold (valley)

30. Movements within the Earth Forces within earth’s crust 4. Stresses A. Compression- rocks squeeze together

31. Movements within the Earth Forces within earth’s crust 4. Stresses B. Tension- rocks pull into thin strings

32. Movements within the Earth Forces within earth’s crust 4. Stresses C. Shearing- rocks slide past eachother horizontally Causes earthquakes

33. Movements within the Earth Forces within earth’s crust 5. Other landforms A. Plateaus- flat, raised chunk of land with cliffs on sides

34. Movements within the Earth Forces within earth’s crust 5. Other landforms B. Domes- blister-like hill/bubble filled with molten rock

35. Assessment Compare and contrast fractures and faults

36. Assessment Describe the interior layers of the Earth

37. Assessment Compare the processes that create fault block mountains and valleys

38. Assessment Describe the activities that can occur along faultlines

39. Assessment Describe the types of folds that the earth’s crust can undergo

40. Assessment Relate the theory of plate tectonics to earthquake and volcano formation

41. Assessment Explain how earthquakes occur

42. Assessment Explain how volcanoes can occur

43. Assessment Compare compression, tension and shearing

44. Assessment Describe the differences between domes, plateaus and mountains