Tectonic Plates

Tectonic Plates

1. Earth's Surface

   • Inner Core
     • Centre. Hottest part of Earth. Solid + made up of iron + nickel with temps up to 5,500°C.
   • Outer Core
     • Layer surrounding inner core. Liquid layer, also made of iron + nickel. Extremely hot, with temps similar to inner core.
   • Mantle
     • Widest section of Earth. Thickness approximately 2,900 km. Made up of semi-molten rock - magma. Upper parts of mantle, rock is hard - lower down, rock is soft + beginning to melt.
   • Crust
     • Outer layer of earth. Thin layer, between 0-60 km thick. Solid rock layer where we live.
   • Tectonic Plates
     • Crust - divided into lots of slabs - float on the mantle.
     • Continental Crust
       • Carries land. Thicker + less dense than oceanic crust.
     • Oceanic Crust
       • Carries water. Thinner + more dense than continental crust.
       • Ocean Trenches
         • Very deep sections of ocean floor where oceanic plate goes down.
   • Plate Margins
     • Places where plates meet.

2. Plate Margins

   • Destructive Margins
     • Where 2 plates are moving towards each other, e.g. along coast of Japan.
     • 1. Oceanic meets continental plate.
       • 2. Denser oceanic plate forced down into mantle + destroyed.
         • 3. Often creates volcanoes + ocean trenches.
   • Constructive Margins
     • Where 2 plates are moving away from each other e.g. at mid-Atlantic ridge.
     • Magma rises from mantle to fill gap + cools, creating new crust.
   • Conservative Margins
     • Where 2 plates are moving sideways past each other or moving in same direction at different speeds e.g. along west coast of USA.
     • Crust isn't created or destroyed.