Landform Geography

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Landform Geography
Plate Tectonics
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Plate Tectonics

• Theory that Earths crust consists of plates that
  move individually collectively
• Helps explain location of mtn ranges,
  earth-quakes, volcanoes other landforms
• First theorized by Wegener in early 1900s
• Pangaea supercontinent that existed 300 my ago
  continents spread by Continental Drift
• Theory ignored through 1950s validated in more
  recent research

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Mechanisms of Continental Drift
Magma Plume pushes plates apart
Convection within Earth
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Seafloor Age
Red youngest through green yellow to blue,
oldest
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Current Locations of Plates
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Types of Plate Movements

• Plate Boundaries (Margins)
• Passive
• Active
• Plate Divergence
• Plate Convergence
• Collision
• Subduction

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Passive Plate Boundary
Where continental crust and bordering oceanic
crust are on the same tectonic plate
tectonically stable
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Convergent Plate Boundary
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Transform Plate Boundary

• Boundaries where plates slide past each other
  horizontally

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Plate Divergence

• Lithospheric plates moving away from each other
• Magma plumes move up out through plate
  fractures, plates spread in process called
  Rifting
• As plates spread, Mid-Oceanic Ridge forms from
  rifting

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Rift Valley

• A rift is a fracture in the earth's surface that
  widens over time, or more technically, is an
  elongate basin bounded by opposed steeply dipping
  normal faults

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Rifting in East Africa
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Plate Convergence Subduction

• Process in which one converging plate is forced
  beneath another, usually oceanic plate under
  continental

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Orogenesis Oceanic-continental Collision
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Oceanic-Oceanic Collision
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Continental-Continental Collision
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Georgia Physiographic Regions
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The Appalachian Mountains