Plate Tectonics

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Plate Tectonics
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Continental Drift

• Crust is broken into plates that are in constant,
  very slow motion, driven by convection currents
  in the mantle.
• Puzzle-like fit of continents
• Similar fossils on different continents
• Similar rock structures on different continents
• Warm weather plant fossils and fossil fuels in
  arctic areas and glacier deposits in tropical
  areas

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Divergent
Boundaries

• Ocean Sea Floor Spreading
• Ocean plates are being pushed apart by
  convection currents and new ocean floor is made
• Crustal Features Rift Valleys on land and
  Mid-Ocean Ridge in ocean

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Sea Floor Spreading
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Rift Valley on Land
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Convergent
Boundaries

• Continental-Continental huge mountains

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Continental-Continental
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Convergent
Boundaries

• Continental-Continental huge mountains
• Continental-Oceanic Subduction! The
• more dense oceanic crust sinks under
• the continental. Trenches, mountains, and
• volcanoes occur.

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Oceanic-Continental
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Convergent
Boundaries

• Continental-Continental huge mountains
• Continental-Oceanic Subduction! The
• more dense oceantic crust sinks under
• the continental. Trenches, mountains, and
• volcanoes occur.
• Oceanic-Oceanic Subduction! Very deep trenches
  and volcanoes

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Oceanic-Oceanic
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Transform
Boundaries

• A plate boundary where two plates move past each
  other in opposite directions
• Makes faults and causes earthquakes

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Transform Boundaries
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Find the Nazca plate on the map. What direction
is it moving?

• The Nazca plate is moving east

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Find the South American plate and describe its
movement.

• The South American plate is moving west

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What do you think will happen as these plates
continue to move?

• As the plates move, they will collide (convergent
  boundary)
• Since the Nazca plate is oceanic crust and the
  South American plate is continental crust, the
  Nazca will plunge beneath the South American
  plate