Continental Drift

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Continental Drift
A theory of moving continents
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Did you know?

• "The crust of the Earth must be a shell floating
  on a fluid interior.... Thus the surface of the
  globe would be capable of being broken and
  distorted by the violent movements of the fluids
  on which it rested".
• Ben Franklin
• 1782

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What is continental drift?

• In 1910, Alfred Wegener proposed continental
  drift and published Origin of Continents
  and Oceans in 1915.

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What is continental drift?

• Wegener theorized that around 250 million years
  ago, a supercontinent PANGAEA, was slowly split
  apart by forces within the Earth to their current
  positions.

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The Shapes Match

• Wegener suggested that the continental coastlines
  on the opposite sides of the Atlantic Ocean could
  be fitted together like jigsaw puzzle pieces.

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The Plants and Animals Match

• Plant animal fossils were similar across oceans.

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The Plants and Animals Match

• He added that plant animal fossils were similar
  across oceans.

Glosssopteris
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The Plants and Animals Match

• Mesosaurus

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The Rocks Match

• Broad belts of rocks in Africa and South America
  are the same type. These broad belts then match
  when the end of the continents are joined

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The Ice Matches

• Wegener was aware that a continental ice sheet
  covered parts of South America, southern Africa,
  India, and southern Australia about 300 million
  years ago.

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Glacial Striations on rocks

• Glaciers moved from Africa toward the Atlantic
  Ocean and from the Atlantic Ocean onto South
  America. Such glaciation is most likely if the
  Atlantic Ocean were missing and the continents
  joined

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Why Few People Believed

• Wegener could not explain the FORCE that pushed
  or pulled the continents