The document discusses the theory of plate tectonics, including what plates are made of, how they move at boundaries, and the evidence that supports plate tectonics. The lithosphere comprises the crust and rigid upper mantle, floating on the asthenosphere. Plates move at boundaries in three types - divergent, convergent, and transform - which are associated with volcanoes, earthquakes, and other surface phenomena. Evidence like matching continents, widespread fossil distributions, and matching rock formations support plate tectonics and the past connection of continents.

2. Areas of Interest Plate Tectonics Plate Boundaries Causes of Plate Tectonics Evidences Earth Tectonic Plates

3. Plate Tectonics

4. Plate tectonics (from Greek tektōn "builder") is a theory of geology that has been developed to explain the observed evidence for large scale motions of the Earth 's lithosphere The outermost part of the Earth's interior is made up of two layers: above is the lithosphere , comprising the crust and the rigid uppermost part of the mantle . Below the lithosphere lies the asthenosphere

5. The lithosphere is broken up into what are called tectonic plates The lateral movement of the plates is typically at speeds of 0.66 to 8.50 centimeters per year This movement is caused by convection current in the mantle

6. Mid-Atlantic Ridge moves as fast as fingernails grow

7. Continental Drift Theory

9. Super-Continent PANGAEA

10. Sea-Floor Spreading

11. Atlantic 65 m.y. ago

12. Present Day Atlantic

13. Continental Drift + Sea Floor Spreading = Plate Tectonics

14. These plates move in relation to one another at one of three types of plate boundaries: convergent or collision boundaries, divergent or spreading boundaries, and transform boundaries. Earthquakes , volcanic activity , mountain -building, and oceanic trench formation occur along plate boundaries

15. Types of plate boundaries Three types of plate boundaries exist, characterized by the way the plates move relative to each other. They are associated with different types of surface phenomena. The different types of plate boundaries are: Transform Plate Boundaries Divergent Plate Boundaries Convergent Plate Boundaries

16. The Earth’s Plates

18. Plate Boundaries and Earthquakes

20. Transverse bounaries occur where the plates slide laterally past one another The San Andreas Fault in California is one example. Other examples of transform faults include the Alpine Fault in New Zealand and the North Anatolian Fault in Turkey .Volcanoes are rare but earthquakes are common. 1. Transform boundaries

22. San Andreas Fault, CA

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

24. Features of Divergent Boundaries Mid-ocean ridges rift valleys fissure volcanoes

25. Bridge across the Álfagjá rift on the Reykjanes peninsula in southwest Iceland , the boundary of the Eurasian and North American continental tectonic plates.

29. 3. Convergent Boundaries Boundaries between two plates that are colliding   There are 3 types…

30. Type 1 Ocean plate colliding with a less dense continental plate Subduction Zone: where the less dense plate slides under the more dense plate VOLCANOES occur at subduction zones

32. Type 2 Ocean plate colliding with another ocean plate The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH

34. Type 3 A continental plate colliding with another continental plate Have Collision Zones: a place where folded and thrust faulted mountains form.

36. Convection Currents Hot magma in the Earth moves toward the surface, cools, then sinks again. Creates convection currents beneath the plates that cause the plates to move.

38. What Drives the plates?

39. The Plate Tectonics Model

40. The Plate Tectonics Model

41. Evidence for Continental Drift Early Evidence Puzzle-like fit of the continents Fossil clues Mesosaurus Glossopteris Plants Climate clues Glaciers Glacial deposits Rock clues

42. A. Puzzle-like fit of the Continents The edges of some continents look as if they would fit together like a puzzle.

43. South America Africa Coast Line Fit:

44. Fit of Continents Across the Atlantic

45. B. Fossil Clues: Mesosaurus A freshwater swimming reptile Fossils found in South America and Africa. Wegener thought that this reptile lived on both continents when the continents were connected.

46. Fossil Clues: Glossopteris Fossil Fern Found in Africa, Australia, India, South America and Antarctica. Wegener believed that all these areas were connected.

47. Ancient Fossils: Plants and Dinosaurs

48. Climate Clues: Glacial Deposits Glacial deposits and grooved bedrock found in southern areas of South America, Africa, India, and Australia. Indicates that these continents were once covered with glaciers. Wegener believed that these continents were covered with ice near Earth’s South Pole at one time.

49. C. Climatic Clue :Ancient Glaciations

50. Present Glaciations

51. Rock Clues Similar rock structures are found on different continents. Mountains found in the eastern U.S. are similar to those found in Greenland and western Europe. The clues found in rocks, support the idea that continents were connected when these rock structures formed.

52. Rocks Clues :Ancient Mountains

53. Present Mountains

54. EARTH TECTONIC PLATE

56. Major Plates The main plates are: African Plate covering Africa - Continental plate Antarctic Plate covering Antarctica - Continental plate Australian Plate covering Australia (fused with Indian Plate between 50 and 55 million years ago) - Continental plate Eurasian Plate covering Asia and Europe - Continental plate North American Plate covering North America and north-east Siberia - Continental plate South American Plate covering South America - Continental plate Pacific Plate covering the Pacific Ocean - Oceanic plate

57. The minor Plates are: Caribbean Plate Arabian Plate Cocos Plate Juan de Fuca Plate Nazca Plate Philippine Plate Scotia Plate Minor Plates

58. Activity # 01

59. Questions... What is the theory of plate tectonics? What is the lithosphere? What is the asthenosphere? What is the connection between the two? What are the two types of plates?

60. Questions... What are the three types of boundaries? What direction do plates go for each? Which boundary has a subduction zone…what occurs at a subduction zone?

61. Questions... What causes plates to move? How is a convection current formed?

62. What is the Lithosphere? The crust and part of the upper mantle = lithosphere 100 km thick Less dense than the material below it so it “floats”

63. What is the Asthenoshere? The plastic layer below the lithosphere = asthenosphere The plates of the lithosphere float on the asthenosphere

65. Causes of Plate Tectonics

66. 2 Types of Plates Ocean plates - plates below the oceans Continental plates - plates below the continents

68. Andes Mountains, South America

69. How Plates Move

70. Aleutian Islands, Alaska

72. Benioff’s Interpretation Updated

73. Where Does Ocean Crust Go? Hugo Benioff, 1954

74. Where the Plates Meet

75. Hot Spots: Hawaii

76. Brief History of Plate Tectonics Idea of Continental Drift began to form in 1830’s when the shapes of the continents across the Atlantic were known Alfred Wegener was the first one to systematically expound the idea Lack of reliable data prevented the acceptance of the such model until its revival in early 1960’s

78. Rates of Plate Motions The relative plate motion rates vary from about 2 cm to over 10 cm/yr Average rate: about 5 cm/yr or as fast as your finger nail growth San Andreas – average rate Pacific Plate near Japan – 10 cm/yr

80. Scientists Reject Wegener’s Theory Wegener provided more than evidence for his theory. He attempted to explain how drift took place. Unfortunately, Wegener could not provide a satisfactory explanation for the force that pushes or pulls the continents. Therefore, scientists rejected his theory.

81. Climate Clues Fossils of warm weather plants were found on islands in the Arctic Ocean. Wegener believed that these islands drifted from tropical regions.