2. Plate Tectonics1 The Earths’ Interior

3. Plate Tectonics2 Earth Facts

4. Plate Tectonics3 Happy the man whose lot it is to know the secrets of the earth. He hastens not to work his fellows' hurt by unjust deeds, but with rapt admiration contemplate immortal Nature's ageless harmony, and how and when her order came to be. Such spirits have no place for thoughts of shame. - Euripides (484-406 B.C.) Don’t copy this slide

5. Plate Tectonics4 Inside the Earth

6. Plate Tectonics5 Crust The exterior portion of the earth Lies above the Moho discontinuity

7. Plate Tectonics6 Crust 3 types of solid rock – igneous, sedimentary, & metamorphic Oxygen & silicon Oceanic crust 8 km thick: basalt Continental crust 32km thick: granite & basalt

8. Plate Tectonics7 Elements in the Crust Oxygen 46.6% Silicon 27.72% Aluminum 8.13% Iron 5.00% Calcium 3.63% Sodium 2.83% Potassium 2.59% Magnesium 2.09% Titanium 0.40% Hydrogen 0.14% Don’t Copy

9. Plate Tectonics8 Mantle Layer between the crust and the core Silicon, oxygen, iron & magnesium 870°-2200°c 2900 km thick

10. Plate Tectonics9 Lithosphere Thin outer shell of the earth Consisting of the crust and the rigid upper mantle

11. Plate Tectonics10 Lithosphere Rigid layer Broken up into 7 major lithospheric plates

12. Plate Tectonics11

13. Plate Tectonics12 Asthenosphere Zone of the mantle beneath the lithosphere Consists of slowly flowing solid rock Plasticity: when solid rock flows

14. Plate Tectonics13

15. Plate Tectonics14 Moho The Mohorovicic discontinuity Croatian scientist found increased speed of seismic waves Boundary between the mantle and the earth’s crust Reveals increase in density

16. Plate Tectonics15 Seismic Waves

17. Plate Tectonics16 Shadow Zones Location on the earth’s surface where no seismic waves or only P waves can be detected.

18. Plate Tectonics17 Core Central portion of earth Below the mantle Depth of about 2,900 kilometers (1,800 miles) Consisting of iron and nickel Liquid outer core and a solid inner core

19. Plate Tectonics18 Magnetosphere

20. Plate Tectonics19 Magnetosphere Region of space that is affected by the Earth’s magnetic field

21. Plate Tectonics20 The Dynamic Earth Plate Tectonics

22. Plate Tectonics21 Theory of Continental Drift 1900’s Alfred Wegener proposed that the earth used to be one giant landmass that split to form today’s continents

23. Plate Tectonics22 Continental Drift Pangaea –“all lands” –a single landmass –origin of all the continents Panthalassa –“all seas” –giant ocean that must have surrounded Pangaea.

24. Plate Tectonics23 Wegener's Evidence for Continental Drift The shape of continents suggests they once fit together –Noticed first in 1858 as soon as good maps were being made

25. Plate Tectonics24 Wegener's Evidence for Continental Drift Fossils – The glossopterus flora and fauna are now found in widely separated continents in the southern Hemisphere.

26. Plate Tectonics25 Fossil Evidence Fossils support Wegener’s theory Glossopteris Mesosaurus Lystrosaurus Cynognathus

27. Plate Tectonics26 Wegener's Evidence for Continental Drift Paleoclimate evidence Distribution of Paleozoic –Coral reefs –Coal beds –Deserts 250-300 million years ago

28. Plate Tectonics27 Wegener's Evidence for Continental Drift Rock types and mountain ranges can be traced across now widely separated continents.

29. Plate Tectonics28 Rock Evidence Glacial deposits Folded mountains Coal deposits

30. Plate Tectonics29 Wegener's Evidence for Continental Drift Evidence of ancient glaciers in all of the southern continents Do you think all of this satisfied the critics?

31. Plate Tectonics30

32. Plate Tectonics31 Where is the Force? What makes the plates move? The answer is on the ocean floor

33. Plate Tectonics32 Mid-ocean Ridge System of undersea mountain ranges Wind around the earth 65,000 km Ocean rocks much younger than continental rocks

34. Plate Tectonics33 Mid-Atlantic Ridge Undersea mountain range Steep, narrow valley down the center

35. Plate Tectonics34 Seafloor Spreading Movement of the ocean floor away from either side of a mid-ocean ridge Caused by convection currents

36. Plate Tectonics35 Seafloor Spreading

37. Plate Tectonics36 Convection Cells

38. Plate Tectonics37 Uneven heating causes movement in fluids

39. Plate Tectonics38 Paleomagnetism of the Ocean Floor Magnetic fossil record of the alternating magnetic field of the ocean floor.

40. Plate Tectonics39 Plate Tectonics Theory that the lithosphere is made up of plates that float on the asthenosphere Plates possibly moved by convection currents

41. Plate Tectonics40

42. Plate Tectonics41

43. Plate Tectonics42 Types of Crust Oceanic crust –Material that makes up the ocean floor Continental crust –Material that makes up landmasses

44. Plate Tectonics43 Divergent Boundary Formed by two lithospheric plates that are moving apart

45. Plate Tectonics44 Rift Valley Steep, narrow valley Formed as lithospheric plates separate

46. Plate Tectonics45 Convergent Boundary Border formed by the collision of two lithospheric plates

47. Plate Tectonics46 Continental vs. Continental

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49. Plate Tectonics48

50. Plate Tectonics49

51. Plate Tectonics50 Oceanic vs Continental

52. Plate Tectonics51 Subduction Zone Region where one lithospheric plate moves under another.

53. Plate Tectonics52 Ocean Trench Formed when one oceanic crust is subducted under another oceanic crust

54. Plate Tectonics53 Oceanic vs Oceanic

55. Plate Tectonics54 Island arc Chain of volcanic islands Formed by subduction at ocean trenches

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57. Plate Tectonics56 Transform Fault Boundary Formed by two lithospheric plates that slide past each other

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59. Plate Tectonics58 Theory of Suspect Terrains – theory that continents are a patchwork of pieces of land that have individual geologic histories

60. Plate Tectonics59 The earth was made so various, that the mind of solitary man, studious of change and pleased with novelty, might be indulged. - Cowper, English poet

61. Plate Tectonics60

62. Plate Tectonics61 Crust Asthenosphere –Lithosphere

63. Plate Tectonics62 Continental Drift Hypothesis stating that the continents once formed a single landmass Broke up and drifted to their present location

64. Plate Tectonics63 The Earths’ Interior