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
A hypothesis stated by Alfred Wegener. The
continents once formed a single land mass, broke
up, and drifted to their present location.
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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

• Mesosaurus Lystrosaurus- found in places now
  separated by oceans
• Glossopteris- 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 chains in
  Earths ocean basin where seafloor spreading
  takes place.
• Seafloor Spreading is the process by which 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

• Some of the most important evidence of sea-floor
  spreading.
• 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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