Restless Continents: Chapter 7, Section 2

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Restless Continents Chapter 7, Section 2

• What will you learn
• You will be able to identify the types of
  evidence Alfred Wegener used to support the
  theory of continental drift.

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Continental Drift
Hypothesis by Alfred Wegener. Theory The
continents once formed a single land mass, broke
up, and drifted to their present location.
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Pangea

• Pangea single, huge super continent meaning ALL
  EARTH.
• Split into 2 continents
• Laurasia (North)
• Gondwana (South)
• Continue to split to present day

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Evidence from Landforms

• Puzzle-like fit mountain ranges of Africa
  South America line up

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Evidence from Coal Deposits

• European coal fields match up with similar coal
  fields in North America

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Evidence from Fossils

• Dinosaur fossils - found in places now separated
  by oceans
• Fernlike plant found in rocks in Africa, S.
  America, Australia, India, Antarctica

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Evidence from Climate

• Island of Spitsbergen
• Lies in Arctic Ocean harsh, polar climate
• Fossils of tropical plants found here
• Glaciers
• Evidence of past continental glaciers found in
  rocks of South Africa

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Rodinia
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Mid Ocean Ridges Seafloor Spreading

• Mid-Ocean Ridges underwater mountain chain where
  seafloor spreading takes place.
• Seafloor Spreading process where new oceanic
  lithosphere forms as magma rises towards the
  surface and solidifies.

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Magnetic Reversal
Magnetic Reversal- When Earths magnetic poles
change place
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Magnetic Reversals

• Magnetic Minerals- molten rock found at mid-ocean
  ridges that act like compasses aligning with the
  magnetic field on earth
• Recorded in rocks as they move on the seafloor
• Reverses minerals align in opposite direction
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