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Continental Drift

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Gondwanaland - Southernmost ... South America, Australia and India. Laurasia -included most of the landmasses that make up today s northern hemisphere. Gondwanaland ... – PowerPoint PPT presentation

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Title: Continental Drift


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Continental Drift
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Alfred Wegener
  • In 1910, Alfred Wegener became curious about the
    continents. He formed a hypothesis that the
    continents had moved.

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  • Wegeners hypothesis was that all continents had
    been joined together in a single landmass and
    have since moved apart.

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  • He named this super continent Pangaea. This idea
    was known as Continental Drift.

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Evidence
  • 1. Landforms
  • Mountain ranges and other features on continents
    provided evidence. South America and Africa fit
    together like puzzle pieces. A mountain range in
    South America lined up with a mountain range in
    Africa. European coal fields matched up with ones
    in North America.

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  • 2. Fossils
  • A fossil is a trace of an organism preserved in
    rock. Fossils of the reptiles Mesosaurus and
    Lystrosaurus had been found in places now
    separated by oceans. Another example was the
    fern-like plant Glossopteris found in Antarctica,
    Africa, South America, Australia and India.

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Laurasia
  • -included most of the landmasses that make up
    todays northern hemisphere.
  • Gondwanaland
  • - Southernmost supercontinent that was once part
    of Pangaea

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  • 3. Climate
  • Fossils of tropical plants were found in
    Antarctica.
  • Glaciers once covered South Africa. Deep
    scratches from the glaciers were found on rocks.

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Rejection of Wegeners Hypothesis
  • Wegener could not provide evidence for the forces
    that push or pull the continents. Many
    geologists in the 1900s thought the earth was
    slowly shrinking and cooling. Wegener disagreed
    with this proposal because mountains usually
    appear in narrow bands along the edge of
    continents

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New evidence today
  • The Ring of Fire showing that the plates once
    were connected and seismic activity in the mantle
    has caused the movement and the eruption of
    volcanoes and earthquakes.

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