Plate Tectonics

• The mantle is between the crust and the core, it's made up of solid rock but can flow slowly over time.
• The outer core is liquid iron and nickel
• The core is the centre of the earth
• The inner core is solid iron and nickel
• Plates are pieces of lithosphere that move around on top of the asthenosphere
• Plates are pieces of lithosphere that move around on top of the asthenosphere (the upper part of the mantle)
• Convection currents occur when hot material rises to the surface and cooler denser material sinks back down again
• Sea floor spreading occurs where new oceanic crust forms at mid-ocean ridges as magma cools and hardens
• Subduction zones form where two plates collide and one plate moves under another (subducts)
• Pangea means "all Earth"
• Alfred Wegener proposed the Continental Drift Theory in 1912
• SONAR was used to map out the ocean
• Denser plates subdects

  Oceanic crusts are denser than continental crusts
• Divergent boundaries - areas where plates move away from each other

  • mid-ocean ridges (o to o, o to c)
  • rift valleys and ravines (c to c)
• Convergent boundaries - areas where plates move towards each other

  • magma chamber/volcanoes (o to c)
  • mountain ranges (c to c)
  • island arcs/underwater volcanoes (o to o)
• Transform boundaries - areas where plates move past each other

  • faults
• Faults:

  Normal - surface shift below level
• Faults:

  Reverse - surface shift above level
• Faults:

  Strike-slip(shearing) - surface shift horizontally in opposite directions