Continental Drift

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Continental Drift

• The Earth on the Move

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Continental Drift

• Most scientists used to believe the Earth to be a
  place that undergoes little change.
• Oceans and land masses have been in their places
  since the beginning of time.

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Alfred Wegner

• Saw evidence that the continents moved and were
  not locked in place like other scientists
  thought.
• Proposed a radical new idea called continental
  drift.
• Stated that the continents plow through the sea.

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Wegners Evidence

1. Continental Jigsaw Puzzle
2. Fossils that Match Across the Sea
3. Rock Types and Structures Matches
4. Ancient Climates

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Continental Jigsaw Puzzle

• With the development of more accurate maps,
  scientists started to notice how the continents
  fit together.
• Wegner proposed that this is because they once
  were together.

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Fossil Match

• Fossils found in one area matched fossils found
  across the sea.
• Cynognathus
• Glossopteris
• Lystrosaurus
• Mesosaurus

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Rock Types

• Rock structures are similar in places that seemed
  to be connected at one time.
• Mountain belts that end in the ocean begin across
  the sea (Appalachian Mts. and Caledonian Mts.)

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Ancient Climates

• Evidence exists of Glaciers in the southern
  hemisphere and of tropical environments in the
  northern hemisphere.
• Was this from moving poles or moving plates?

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What came from this evidence?

• The continental drift hypothesis and Pangaea.
• Pangeameaning 1 world.
• The idea that 300 million years ago, all the
  continents were once formed into a huge super
  continent.

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Where was the evidence?

• Opponents of Wegner said that there was no
  mechanism to make continental drift possible.
• Wegners idea of the continents plowing through
  the sea seemed improbable.
• Wegners ideas were not considered reliable until
  a bit later