Geologic Time


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Geologic Time

  1. 1. Geologic Time Chapter 21-24
  2. 2. Capitol Reef National Park What do the layers of rock have to do with Geologic Time?
  3. 3. What has happened to the rock layers since they were deposited?
  4. 4. Discovery Lab <ul><li>Using the samples placed at the lab stations, complete the Fossil Hunt Activity on page 553. </li></ul><ul><li>Do not throw away the samples…the next class needs to use them. </li></ul>
  5. 5. The Geologic Time Scale <ul><li>A record of the earth’s history form its origin 4.6 billion years ago to the present. </li></ul><ul><li>Each unit or era is based upon the fossils found within rocks. </li></ul><ul><li>Eon – longest time unit measured in billions of years. </li></ul><ul><li>Era – next longest time unit measured in hundreds of millions of years. </li></ul>
  6. 6. Geologic Time Scale
  7. 8. Other Units <ul><li>Periods – defined by the life-forms that were abundant or became extinct during the time in which specific rocks were deposited – measured in 10s or 100s of millions of years. </li></ul><ul><li>Epochs – measured in millions to 10s of millions of years. </li></ul>
  8. 9. Uniformitarianism <ul><li>Processes happening today have always happened just at different rates and intensities. </li></ul>
  9. 10. Superposition
  10. 12. Problem Solving Lab <ul><li>Read and answer question on page 560 (Interpreting Diagrams). </li></ul>
  11. 13. Correlation <ul><li>Matching of outcrops of one geographic region to another. </li></ul>
  12. 14. Radioactive Isotopes and Decay <ul><li>Isotopes are what causes radiation and are part of the study of nuclear chemistry. </li></ul>
  13. 15. Carbon Dating
  14. 18. Radioactive Decay of Uranium 238
  15. 20. Tree Ring Dating
  16. 21. Seasonal Climatic Changes
  17. 22. Distinctive Sediment Layers Key Beds are time markers that correlate rock layers across large areas.
  18. 23. Types of Fossils <ul><li>Fossils are the evidence or remains of once living plants or animals. </li></ul><ul><ul><li>Original preservation – soft or hard parts of plants that have not undergone any kind of change since the organisms death. </li></ul></ul><ul><ul><li>Altered hard parts – changed by mineral replacement or recrystallization. </li></ul></ul>
  19. 24. Permineralization <ul><li>process by which pore spaces are filled with mineral substances </li></ul>
  20. 25. Types of Fossils (cont.) <ul><li>Index Fossils </li></ul><ul><li>Molds and Casts </li></ul><ul><li>Indirect Evidence of Past Life </li></ul>
  21. 27. Design Your Own Geolab <ul><li>Do page 570 and 571. </li></ul>
  22. 28. The Precambrian Earth The first 4 billion years
  23. 29. How old is the Earth?
  24. 30. Zircon <ul><li>Oldest known rock </li></ul><ul><li>4.1 to 4.2 billion years old </li></ul>
  25. 31. Formation of the Crust and Continents
  26. 32. Differentiation <ul><li>The process by which a planet becomes internally zoned when heavy materials sink toward its center and lighter materials accumulate near its surface. </li></ul>
  27. 33. Discovery Lab <ul><li>Page 577 </li></ul>
  28. 34. Cores of the Continents <ul><li>Precambrian Shield – near surface </li></ul><ul><li>Canadian Shield – Precambrian in North America and Canada </li></ul>
  29. 36. Types of Continents <ul><li>Microcontinents </li></ul>
  30. 37. Supercontinents
  31. 38. Precambrian Atmosphere
  32. 39. Why is Oxygen important?
  33. 40. MiniLab <ul><li>Carefully conduct minilab on page 587. </li></ul>
  34. 41. Ocean Formation
  35. 42. Early Life on Earth <ul><li>Evidence shows that the first life forms did not happen until 3.5 billion years ago. </li></ul><ul><li>Earth could not sustain life until then (did not contain oxygen). </li></ul>
  36. 43. Experimental Evidence <ul><li>Amino Acids </li></ul><ul><li>RNA </li></ul><ul><li>DNA </li></ul>
  37. 44. Proterozoic Life
  38. 45. Proterozoic Life <ul><li>Prokaryote – organism that is composed of single cell (no nucleus). </li></ul>
  39. 46. Proterozoic Life <ul><li>Eukaryote – an organism that is composed of cells that contain a nucleus. </li></ul>
  40. 47. Ediacara Fossils <ul><li>Soft bodied organisms found imbedded in rocks (mainly in Australia). </li></ul>
  41. 48. Paleozoic Era
  42. 49. Paleozoic <ul><li>A time of great change! </li></ul><ul><li>This era explains how life moved and evolved into what we have today. </li></ul><ul><li>Explains how valleys and mountains were formed. </li></ul>
  43. 50. MYBP = millions of years before present
  44. 51. Characteristic Sediment
  45. 52. Transgression vs. Regression <ul><li>Transgression – when sea level rises and the shoreline moves further inland. </li></ul><ul><li>Regression – when sea level falls and causes the shoreline to move seaward. </li></ul>
  46. 53. Early Paleozoic Life Almost all life forms started at this time.
  47. 55. Paleozoic animals
  48. 56. Mass extinction
  49. 57. Middle Paleozoic Sea Level Changes <ul><li>Most of continent covered in beach. </li></ul>
  50. 58. Orogeny – mountain building <ul><li>Taconic Orogeny </li></ul><ul><li>Caledonian Orogeny </li></ul><ul><li>Acadian Orogeny </li></ul><ul><li>Antler Orogeny </li></ul>
  51. 59. Late Paleozoic
  52. 63. Mesozoic <ul><li>Triassic, Jurassic and Cretaceous Periods </li></ul><ul><li>Break up of pangaea – new oceans formed </li></ul>
  53. 64. Triassic Period – Pangaea breaks apart and new seaways formed. Jurassic – dinosaurs Cretaceous – Flowering plants
  54. 65. Mesozoic Life <ul><li>Modern Fauna – marine organisms </li></ul><ul><li>Reef Builders </li></ul><ul><li>Ammonite Fossils – nautiluses, octopus, squid. </li></ul><ul><li>Insects </li></ul><ul><li>Angiosperm – plants </li></ul><ul><li>Early Mammals </li></ul><ul><li>Flying reptiles </li></ul><ul><li>Dinosaurs </li></ul>
  55. 66. Flying reptiles Modern Fauna Reef Builders
  56. 67. Ammonite Fossils
  57. 68. Insects Angiosperm
  58. 69. Dinosaurs
  59. 70. Mass Extinction
  60. 71. Cenozoic Era <ul><li>Recent Life </li></ul><ul><li>Final breakup of pangaea </li></ul><ul><li>Ice age </li></ul>
  61. 72. Cenozoic Life <ul><li>Pleistocene Mammals </li></ul><ul><li>Primates </li></ul><ul><li>Humans </li></ul>
  62. 73. Pleistocene Mammals
  63. 74. Primates
  64. 76. Humans