Plate Tectonics

• • The surface of the Earth is divided into a number of tectonic plates - these are constantly moving due to convection currents in the mantle - movement of the plates causes the continents to move.
• • The edges of the tectonic plates = plate boundaries - location of the boundaries have been determined by plotting the epicentre of earthquakes and location of volcanoes onto a map of Earth’s surface.
• Earth’s tectonic plates and direction the move

  
• There are three types of plate boundary:

  • Conservative plate boundary
  • Destructive plate boundary
  • Constructive plate boundary
• CONSERVATIVE plate boundary

  • Plates slide past each other. Pressure build until they shudder and move (overcome friction and move suddenly).
  • Earthquakes occur here.
• DESTRUCTIVE plate boundary

  • Plates move towards each other. The denser ocean plate slides under the continental plate and melts to form magma.
  • Volcanoes, mountain ranges and ocean trenches form.
• CONSTRUCTIVE plate boundary

  • Plates move apart. Magma rises to fill the gap between plates, cools and (solidifies) forms new igneous rock.
  • Volcanoes and new land forms.