Plate Tectonics

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JOURNAL ANSWERS

• 1. 67 of the earth MANTLE
• 2. Liquid rock in mantle MAGMA
• 3. Extra credit layers ASTHENOSPHERE, LOWER
  MANTLE
• 4. Olivine GREEN
• 5. Plate movement HEAT INSIDE THE EARTH

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Plate Tectonics

• The Earths Crust in Motion

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The Theory
In 1910 Alfred begins to wonder
Whats the relationship? Perhaps all these
pieces used to be connected. Continental
driftslow movement over Earths surface 300
million years ago
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Supercontinent

• Pangaea all lands
• Reptiles and insects
• Tropical forests
• -coal deposits

?Tens of Millions of years!
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Structure of the Earths Interior
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How does it work?
Plates pieces of the lithosphere Plates fit
closely together along cracks called Plate
Boundaries Convection Currents ? movement
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Types of Boundaries

• Divergent
• Convergent
• Transform

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A Divergent B Convergent C Transform

• plates are moving apart
• new crust is created
• Magma is coming to the surface

• plates are coming together
• crust is returning to the mantle

• plates are slipping past each other
• crust is not created or destroyed

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A Divergent B Convergent C Transform
Continental crust ? rift valley Oceanic crust ? mid-ocean ridge 2 continental plates ? mountain range Plates move against each other Stress builds up Stress is released ?earthquake
2 oceanic plates or oceanic continental
?subduction
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The Big Picture