Dynamic Earth


Published on

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Dynamic Earth

  1. 1. The Earth’s Interior
  2. 2. The Earth’s Interior <ul><li>Four Layers (see page 10 of Ref Tables) </li></ul><ul><li>Inner Core : solid, dense, 6,000 º C, Iron and Nickel </li></ul><ul><li>Outer Core : Liquid, dense, 3,700º-5,500ºC (increases with depth), Iron and Nickel </li></ul><ul><li>Mantle : Solid, minerals rich in Fe, Si, Ma, 1,500º - 3,200º C </li></ul><ul><li>Crust : upper layer, rigid, lighter rock, <1,000ºC </li></ul>
  3. 3. The Earth’s Interior <ul><li>Some terms to know: </li></ul><ul><li>Asthenosphere : Upper layer of the mantle, may act in a semi-fluid (plastic) manner </li></ul><ul><li>Moho (Mohorovicic Discontinuity): The boundary between the mantle and the crust </li></ul><ul><li>Lithosphere : Consists of the crust and the rigid upper mantle </li></ul>
  4. 4. The Earth’s Interior <ul><li>Where is the crust thickest? </li></ul><ul><li>Mountain Ranges. </li></ul><ul><li>Where is the crust thinnest? </li></ul><ul><li>The Ocean Floor. </li></ul>
  5. 5. The Earth’s Interior <ul><li>Why is the core so hot? </li></ul><ul><li>Still retains heat from original formation. </li></ul><ul><li>Radioactive materials releasing energy as they decay. </li></ul><ul><li>Increased pressure from above. </li></ul>
  6. 7. The Earth’s Interior <ul><li>What happens to rock density, going from the crust to the core? </li></ul><ul><li>It increases. </li></ul><ul><li>What happens to temperature, going from the crust to the core? </li></ul><ul><li>It increases. </li></ul><ul><li>What happens to pressure, going from the crust to the core? </li></ul><ul><li>It increases. </li></ul>
  7. 8. Continental Drift and the Origin of Plate Tectonics
  8. 10. Wegener’s Map showing the breakup of Pangea See Reference Table Page 9
  9. 11. Note how they fit together
  10. 12. I.The Theory of Plate Tectonics : <ul><li>The Earth’s lithosphere is made of a number of solid pieces, called __________ which move in relation to each other. </li></ul>plates
  11. 13. These plates are “riding”on a more “plastic molten” layer below These plates are “riding”on a more “plastic molten” layer below
  12. 14. This plastic molten layer of magma is called the: asthenosphere
  13. 16. <ul><li>1. Theory of Continental Drift </li></ul><ul><li>Proposed by _______ ________ in 1915. It stated that the earth’s continents separated and collided as they have moved over the surface of the Earth for millions of years. </li></ul>Alfred Wegener
  14. 17. Alfred Wegener (1880-1930) Geographer and Polar Explorer
  15. 18. <ul><li>B. Wegener’s evidence for his </li></ul><ul><li>his theory: </li></ul><ul><li>1. When you line up __________ </li></ul><ul><li>and _________ </li></ul><ul><li>they fit like a puzzle. </li></ul>S.America Africa
  16. 20. 2. __________ species have been found on widely separated parts of the earth. Fossil
  17. 21. 3. Permian fossils are very similar in widely separated continents
  18. 22. Cynognathus
  19. 23. Lystrosaurus
  20. 24. <ul><li>Mt. Sirus </li></ul><ul><li>Antarctica </li></ul><ul><li>Lystrosaurus beds </li></ul>
  21. 25. Mesosaurus
  22. 26. 3. _____________ and ______________ have a good match of ancient continental rocks and tectonic _________ and _________ structures. S. America Africa fault fold
  23. 27. 4. Some mountain chains appear to be continuous from ____________ to______________ continent continent
  24. 28. 5. Evidence of _________ climates different from present. ancient Ex . Finding coal beds which indicate tropical climates
  25. 29. Technology developed during WWII <ul><li>Sonar - image the deep ocean using reflected sound. </li></ul><ul><li>Magnetometer - detect faint magnetic fields. </li></ul><ul><li>Developed to search for U-boats </li></ul>
  26. 30. World War II Submarine warfare
  27. 32. Harry Hess <ul><li>Geologist at Princeton U. </li></ul><ul><li>1962 publishes “geopoetry.” </li></ul><ul><li>Sea floor spreading hypothesis. </li></ul><ul><li>Suggested that the ocean floor itself might be moving. </li></ul>
  28. 33. Cold War Nuclear Submarines <ul><li>SSN Nautilus </li></ul><ul><li>1st nuclear powered submarine </li></ul>
  29. 34. Mid-ocean ridge
  30. 36. 6 . Rocks of the ocean basins are _________ than continental rocks. younger
  31. 37. II. Ocean Floor Spreading: <ul><li>Further evidence of horizontal movement of earth’s crust: </li></ul><ul><li>A. The ocean floor has a system of submerged mountain ranges called ______________________ </li></ul>Mid-Ocean Ridges
  32. 38. Material from deep within the earth comes to the surface at the ___________________ where it spreads apart to make ________________. Ocean ridges New ocean crust
  33. 40. Sea floor spreading
  34. 41. B. The two major pieces of evidence are: Age of igneous ocean material 1. 2. Reversal of magnetic polarity
  35. 42. When rock hardened it kept the alignment forming a permanent record of the ___________________ of the earth at that time. Magnetic field
  36. 44. N S
  37. 45. N S
  38. 47. N S Magnetic polarity reversal
  39. 49. Rocks found farther from the ridges have a _____________ magnetic polarity. Parallel stripes of ________________ on either side of these ridges preserve the record of many ____________ of the earth’s magnetic field. reversed magnetism reversals
  40. 50. Measuring the Age of the Ocean Floor <ul><li>1968, establishment of the Deep Sea Drilling Project (DSDP). </li></ul><ul><li>Specially outfitted ship for drilling into the ocean floor and retrieving rock samples. </li></ul><ul><li>Sediment layers and igneous rock dated to reveal the age of the ocean floor in different places. </li></ul>
  41. 51. Deep Sea Drilling Project ship - Glomar Challenger
  42. 52. C. The _______ _________ (basaltic) igneous rocks of the crust near the ocean ridges are covered with a thin layer of ____________. dark dense sediment
  43. 53. This is evidence that the earth’s crust is very ___________ near the ridges. young
  44. 56. The oldest parts of the ocean crust are found far from the ___________ ridges and near the _______________ ocean continents
  45. 58. Acceptance of Sea Floor Spreading (Plate Tectonics) <ul><li>1970’s - rapid confirmation of remaining predictions and acceptance of the basic theory by most geologists. </li></ul><ul><li>1980’s - Plate Tectonics becomes the dominant paradigm in geology. </li></ul><ul><li>1990’s - Development of a detailed plate tectonic history of the last 700 million years. </li></ul>
  46. 59. <ul><li>Lesson 2 </li></ul>
  47. 60. Lithospheric Plates ___________ in size and are made up of a combination of ___________ crust and ______________ crust vary oceanic continental
  48. 61. Three kinds of plate motion occur at plate boundaries: <ul><li>1. _____________________ </li></ul><ul><li>2. _____________________ </li></ul><ul><li>3. _____________________ </li></ul>convergent divergent transform
  49. 66. Aerial view of the San Andreas fault slicing through the Carrizo Plain in the Temblor Range east of the city of San Luis Obispo. (Photograph by Robert E. Wallace, USGS.)
  50. 68. <ul><ul><li>1a.When ocean collides with continent the_________ ocean plate dives down under or ____________ into the mantle forming a </li></ul></ul><ul><ul><li>___________________ </li></ul></ul>denser subducts Subduction zone
  51. 69. Oceanic-Continental Convergence Ex. Andes in S.America
  52. 70. 1b.When two ocean plates converge the _______ ___________ocean plate will __________ forming an ____________ ________ older subduct island arc denser
  53. 71. Oceanic-Oceanic Convergence Ex. Indonesia, Phillippines,Japan & Aleutians
  54. 72. <ul><li>Called SUBDUCTION </li></ul>Continent-Oceanic Crust Collision
  55. 73. 1c.When two continental plates converge the edges of _______ are crumpled up forming _________ ________________ both mountains folded
  56. 74. Continental-Continental Convergence Ex. Himalayas
  57. 75. Himalayas
  58. 76. 2.At ____________ plate boundaries, the plates move ___________ and ________ flows up forming parallel ridges made of _______ __________ __________ divergent magma new igneous apart rock
  59. 77. Divergent Plate Boundary Ex. Mid-Atlantic Ridge
  60. 78. <ul><li>Iceland has a divergent plate boundary running through its middle </li></ul>Iceland: An example of continental rifting
  61. 79. 3. At ____________ plate boundaries, the plates move ________ each other causing shallow _____________ _______________ transform earth past quakes
  62. 80. Transform Plate Boundary Ex. San Andreas Fault of California
  64. 82. These plates are “riding”on a more “plastic molten” layer below III. MANTLE CONVECTION CELLS:
  65. 83. The evidence shows that approximately _______ million years ago, the major continents were _______________ 200 connected
  66. 84. And since that time they have been __ _________ separating
  67. 85. A convection cell is a stream of heated material that is moving because of _________ DENSITY DIFFERENCES
  68. 86. These convection cells exist in part of the mantle called the _______________ ASTHENOSPHERE
  69. 87. asthenosphere
  70. 88. The two sources of this heat are: 1. 2. Residual (leftover) heat from the formation of the Earth Heat generated from radioactive decay from the core of the earth
  71. 89. Hot Spots: <ul><li>Places on the Earth’s surface where plumes of __________ are rising up from the mantle not located along ________ _________ ________ </li></ul>magma active Plate boundaries
  72. 91. As a plate passes over a hot spot, a _______________ _______________ forms CHAIN OF VOLCANIC MOUNTAINS
  73. 93. The tectonic plate moves over a fixed hotspot forming a chain of volcanoes. The volcanoes get younger from one end to the other.
  74. 95. The only mountain that _______ ________ is the mountain located directly over the _____ ______ remains active hot spot