Continental%20Drift%20Theory%20Plate%20Tectonics

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Continental Drift TheoryPlate Tectonics
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Tectonics dealing with structural features of
the Earth (e.g., mountains, ocean basins).
Plate Tectonics The process that involves
the interaction of moving crustal plates and
results in major structural features of the
Earth.
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Continental Drift TheoryWhat is it?The
Continental Drift Theory states that the crust of
the earth was once a single continuous layer. As
the core of the earth cooled over the millennia,
the outer crust developed faults (or cracks) and
broke up into several plates which have drifted
apart to form the current continents.
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• The theory of continental drift is based on the
  concept that the continental and oceanic crusts
  are embedded in the uppermost layer of the rocky
  lithosphere.
• The lithosphere is divided into sections called
  tectonic plates, which slide over an underlying
  partly molten layer of rock called the
  asthenosphere.
• The continents passively drift along with the
  moving plates, and over hundreds of millions of
  years this movement alters the entire geography
  of the Earth.

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Plate The Earths crust consists of a number of
mobile plates, masses of crust that move
independently of adjacent plates.
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Alfred Wegener

• As a young scientist, Wegener was curious about
  Earths continents.
• In 1910, Mr. Wegener formed a hypothesis which
  stated all the continents were once joined
  together in a giant landmass.
• He named this landmass PANGAEA.

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Wegener used 3 types of evidence to prove his
theory!

• 1.Evidence from landforms
• 2.Evidence from fossils
• 3.Evidence from climate

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Evidence from landforms

• The shapes of the continents seemed to fit
  together.
• Mountain ranges and other features also lined up.

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Evidence from landforms
The jig-saw puzzle
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Evidence from landforms
The jig-saw puzzle
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Evidence from landforms
The jig-saw puzzle
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Evidence from Fossils

• Fossils from one continent matched fossils from
  other continents.
• Wegener used both plant and animal fossils.

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Evidence from Fossils
fossil matches
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Wegeners Evidence
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Evidence from Climate

• Wegener looked at certain areas on Earth and
  their climates
• He noted that the fossils he found on certain
  sections of Earth did not match the current
  climate
• Glacier scratches in S. Africa

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Evidence from Climate
Antarctic ice
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Evidence from Climate
Ice could not have extended this far.
So...continents MUST have moved..
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The 6,000-km-plus journey of the India landmass
(Indian Plate) before its collision with Asia
(Eurasian Plate) about 40 to 50 million years
ago. India was once situated well south of the
Equator, near the continent of Australia.
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Three types of plate boundary
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TYPES OF MOUNTAINS(according to their origin)

• Block Mountains are formed when there is
  movement along a fault. Eg Vosges(France), Black
  Forest(Germany), Satpurs Vindhyas (India)
• The valleys thus formed are known as Rift
  Valleys.
• (Fault When there is a vertical or
  horizontal movement along a crack.)
• Volcanic

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Fault Block
Block Mountain (Horst) and Rift Valley
(Graben) Examples