Plate tectonic theory

• Earth has 3-layered structure
• Lithosphere is broken up into huge pieces called tectonic plates
• Tectonic plates are constantly moving
• Plate movements result in formation of landform and phenomena
• Core

  • Innermost
  • Highest temperature -> 4400-6000 celsius
  • Thickest -> 3300km
• Mantle

  • In between
  • 1000-3700 celsius
  • 2900km
• Crust

  • Outermost
  • Lowest temperature
  • Thinnest -> 6-70km
• Types of crust

  • Oceanic
  • Continental
• Plate boundaries

  • Divergent
  • Convergent
  • Transform
• Plate movements

  • Convection currents
  • Slab-pull force
• Convection currents

  • Heat from earth’s core causes the mantle materials to become less dense
  • Mantle materials rises toward the surface
  • Rising convection currents spread beneath the plates & drag them apart -> divergent
  • Mantle materials loses heat & sink towards the core
  • Convection currents collide -> convergent
  • Materials get heated up again, process is repeated
• Slab-pull force

  • 2 plate converge, denser oceanic plate is pulled down by gravity as it subducts beneath the less dense crust
  • Denser crust sinks deeper into the mantle under its own weight, pulling the rest of the plate with it
  • Contribute to further convergent