The document summarizes the structure and composition of Earth's interior. It has four main layers from innermost to outermost - the solid inner core made of iron and nickel, the liquid outer core also made of iron and nickel, the solid mantle made of iron, silicon and magnesium minerals, and the rigid outer crust made of lighter rock. Temperature and pressure increase from the crust towards the core. The crust is thinnest under oceans and thickest under mountains.

1. The Earth’s Interior

2. The Earth’s Interior Four Layers (see page 10 of Ref Tables) Inner Core : solid, dense, 6,000 º C, Iron and Nickel Outer Core : Liquid, dense, 3,700º-5,500ºC (increases with depth), Iron and Nickel Mantle : Solid, minerals rich in Fe, Si, Ma, 1,500º - 3,200º C Crust : upper layer, rigid, lighter rock, <1,000ºC

3. The Earth’s Interior Some terms to know: Asthenosphere : Upper layer of the mantle, may act in a semi-fluid (plastic) manner Moho (Mohorovicic Discontinuity): The boundary between the mantle and the crust Lithosphere : Consists of the crust and the rigid upper mantle

4. The Earth’s Interior Where is the crust thickest? Mountain Ranges. Where is the crust thinnest? The Ocean Floor.

5. The Earth’s Interior Why is the core so hot? Still retains heat from original formation. Radioactive materials releasing energy as they decay. Increased pressure from above.

7. The Earth’s Interior What happens to rock density, going from the crust to the core? It increases. What happens to temperature, going from the crust to the core? It increases. What happens to pressure, going from the crust to the core? It increases.

8. Continental Drift and the Origin of Plate Tectonics

10. Wegener’s Map showing the breakup of Pangea See Reference Table Page 9

11. Note how they fit together

12. I.The Theory of Plate Tectonics : The Earth’s lithosphere is made of a number of solid pieces, called __________ which move in relation to each other. plates

13. These plates are “riding”on a more “plastic molten” layer below These plates are “riding”on a more “plastic molten” layer below

14. This plastic molten layer of magma is called the: asthenosphere

16. 1. Theory of Continental Drift 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. Alfred Wegener

17. Alfred Wegener (1880-1930) Geographer and Polar Explorer

18. B. Wegener’s evidence for his his theory: 1. When you line up __________ and _________ they fit like a puzzle. S.America Africa

20. 2. __________ species have been found on widely separated parts of the earth. Fossil

21. 3. Permian fossils are very similar in widely separated continents

22. Cynognathus

23. Lystrosaurus

24. Mt. Sirus Antarctica Lystrosaurus beds

25. Mesosaurus

26. 3. _____________ and ______________ have a good match of ancient continental rocks and tectonic _________ and _________ structures. S. America Africa fault fold

27. 4. Some mountain chains appear to be continuous from ____________ to______________ continent continent

28. 5. Evidence of _________ climates different from present. ancient Ex . Finding coal beds which indicate tropical climates

29. Technology developed during WWII Sonar - image the deep ocean using reflected sound. Magnetometer - detect faint magnetic fields. Developed to search for U-boats

30. World War II Submarine warfare

32. Harry Hess Geologist at Princeton U. 1962 publishes “geopoetry.” Sea floor spreading hypothesis. Suggested that the ocean floor itself might be moving.

33. Cold War Nuclear Submarines SSN Nautilus 1st nuclear powered submarine

34. Mid-ocean ridge

36. 6 . Rocks of the ocean basins are _________ than continental rocks. younger

37. II. Ocean Floor Spreading: Further evidence of horizontal movement of earth’s crust: A. The ocean floor has a system of submerged mountain ranges called ______________________ Mid-Ocean Ridges

38. Material from deep within the earth comes to the surface at the ___________________ where it spreads apart to make ________________. Ocean ridges New ocean crust

40. Sea floor spreading

41. B. The two major pieces of evidence are: Age of igneous ocean material 1. 2. Reversal of magnetic polarity

42. When rock hardened it kept the alignment forming a permanent record of the ___________________ of the earth at that time. Magnetic field

44. N S

45. N S

47. N S Magnetic polarity reversal

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

50. Measuring the Age of the Ocean Floor 1968, establishment of the Deep Sea Drilling Project (DSDP). Specially outfitted ship for drilling into the ocean floor and retrieving rock samples. Sediment layers and igneous rock dated to reveal the age of the ocean floor in different places.

51. Deep Sea Drilling Project ship - Glomar Challenger

52. C. The _______ _________ (basaltic) igneous rocks of the crust near the ocean ridges are covered with a thin layer of ____________. dark dense sediment

53. This is evidence that the earth’s crust is very ___________ near the ridges. young

56. The oldest parts of the ocean crust are found far from the ___________ ridges and near the _______________ ocean continents

58. Acceptance of Sea Floor Spreading (Plate Tectonics) 1970’s - rapid confirmation of remaining predictions and acceptance of the basic theory by most geologists. 1980’s - Plate Tectonics becomes the dominant paradigm in geology. 1990’s - Development of a detailed plate tectonic history of the last 700 million years.

59. Lesson 2

60. Lithospheric Plates ___________ in size and are made up of a combination of ___________ crust and ______________ crust vary oceanic continental

61. Three kinds of plate motion occur at plate boundaries: 1. _____________________ 2. _____________________ 3. _____________________ convergent divergent transform

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.)

68. 1a.When ocean collides with continent the_________ ocean plate dives down under or ____________ into the mantle forming a ___________________ denser subducts Subduction zone

69. Oceanic-Continental Convergence Ex. Andes in S.America

70. 1b.When two ocean plates converge the _______ ___________ocean plate will __________ forming an ____________ ________ older subduct island arc denser

71. Oceanic-Oceanic Convergence Ex. Indonesia, Phillippines,Japan & Aleutians

72. Called SUBDUCTION Continent-Oceanic Crust Collision

73. 1c.When two continental plates converge the edges of _______ are crumpled up forming _________ ________________ both mountains folded

74. Continental-Continental Convergence Ex. Himalayas

75. Himalayas

76. 2.At ____________ plate boundaries, the plates move ___________ and ________ flows up forming parallel ridges made of _______ __________ __________ divergent magma new igneous apart rock

77. Divergent Plate Boundary Ex. Mid-Atlantic Ridge

78. Iceland has a divergent plate boundary running through its middle Iceland: An example of continental rifting

79. 3. At ____________ plate boundaries, the plates move ________ each other causing shallow _____________ _______________ transform earth past quakes

80. Transform Plate Boundary Ex. San Andreas Fault of California

81. core III. MANTLE CONVECTION CELLS:

82. These plates are “riding”on a more “plastic molten” layer below III. MANTLE CONVECTION CELLS:

83. The evidence shows that approximately _______ million years ago, the major continents were _______________ 200 connected

84. And since that time they have been __ _________ separating

85. A convection cell is a stream of heated material that is moving because of _________ DENSITY DIFFERENCES

86. These convection cells exist in part of the mantle called the _______________ ASTHENOSPHERE

87. asthenosphere

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

89. Hot Spots: Places on the Earth’s surface where plumes of __________ are rising up from the mantle not located along ________ _________ ________ magma active Plate boundaries

91. As a plate passes over a hot spot, a _______________ _______________ forms CHAIN OF VOLCANIC MOUNTAINS

93. The tectonic plate moves over a fixed hotspot forming a chain of volcanoes. The volcanoes get younger from one end to the other.

95. The only mountain that _______ ________ is the mountain located directly over the _____ ______ remains active hot spot