Plate tectonics

Plate tectonics

Replaced idea of continental drift
1. 1950s and 1960s
2. 7 large sections called plates
3. A few smaller sections called plates
4. Convection currents
  1. Caused by the intense heat in the mantle
  2. Causes the plates to move
Plate boundaries
1. Where two plates meet
2. Slow movement of the plates
  1. Forms volcanoes and new mountains
  2. Makes earthquakes and tsunamis
Constructive plate boundary
1. Where two plates are moving apart (diverging)
  1. New crust is made
2. Hot magma from the mantle rises to fill the gap
  1. Creates new mountains under the sea
    1. Mid oceanic ridge
3. When new magma continues to build up above the ocean
  1. New volcanic island are made
Destructive plate boundary
1. Two plates move together (continental and oceanic)
  1. Denser continental plate is forced down (subducted) underneath the less dense oceanic crust
    1. creates an ocean trench and causes the material to melt as it is dragged down
      1. The magma rises through cracks as a very violent volcano
2. Earthquakes
Conservative plate boundary
1. Plates meet and slide past eachother
  1. No crust is destroyed or added
    1. Sliding movement is not smooth and immense friction builds up
      1. Eventually one plate suddenly jerks past the other causing shockwaves and an earthquake on the surface
2. Faults are found here due to the plates moving in different directions
Collision plate boundary
1. Two continential plates bump into eachother
  1. Both plates are continental so they buckle and fold
    1. Pushes up the land to create fold mountains

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	Created by sophie.blaker about 10 years ago