1. Geologic Time Chapter 21-24

2. Capitol Reef National Park What do the layers of rock have to do with Geologic Time?

3. What has happened to the rock layers since they were deposited?

6. Geologic Time Scale

10. Superposition

15. Carbon Dating

18. Radioactive Decay of Uranium 238

20. Tree Ring Dating

21. Seasonal Climatic Changes

22. Distinctive Sediment Layers Key Beds are time markers that correlate rock layers across large areas.

28. The Precambrian Earth The first 4 billion years

29. How old is the Earth?

31. Formation of the Crust and Continents

37. Supercontinents

38. Precambrian Atmosphere

39. Why is Oxygen important?

41. Ocean Formation

44. Proterozoic Life

48. Paleozoic Era

50. MYBP = millions of years before present

51. Characteristic Sediment

53. Early Paleozoic Life Almost all life forms started at this time.

55. Paleozoic animals

56. Mass extinction

59. Late Paleozoic

64. Triassic Period – Pangaea breaks apart and new seaways formed. Jurassic – dinosaurs Cretaceous – Flowering plants

66. Flying reptiles Modern Fauna Reef Builders

67. Ammonite Fossils

68. Insects Angiosperm

69. Dinosaurs

70. Mass Extinction

73. Pleistocene Mammals

74. Primates

76. Humans