Geography: Hostile World

Geography: Hostile World

1. Layers of the Earth

   • Inner core - found at the centre of the Earth, 6,500 km deep, 6,200 degrees Celcius, solid ball of metal (iron)
   • Outer core - outer layer of the centre of the Earth, 5,100 km deep, made of molten rock containing metal, Earth's magnetic field
   • Mantle - thickest layer, 700-2900 km deep, 5,000 degrees Celcius, made of molten magma/lava
   • Crust - thinnest layer, 10-70 km deep, the temperature varies, made up of hard, cold rock

2. The Earth formed 4.6 billion years ago in the Big Bang - it consists of four main layers

   • Each layer is different and plays a key role in the formation of volcanoes and earthquakes

3. Plate names

   • North American
   • Juan de Fuca
   • Pacific
   • Cocos
   • Caribbean
   • Nazca
   • South American
   • African
   • Iranian
   • Antarctic
   • Indo-Australian
   • Philippine
   • Eurasian
   • Arabian

4. Plate movement

   • 1) The core has temperatures of 6000 degrees Celcius. This heats up the magma in the lower mantle
   • 2) The magma rises up and as it reaches the upper mantle it cools
   • 3) As the magma becomes colder it also becomes denser and sinks back down into the lower mantle
   • 4) Here the convection current is created. These currents occur throughout the mantle and are responsible for moving the plates
   • 5) The Earth's crust is divided into sections called plates. The plates float on the top of the mantle and due to the convection currents, move in different directions
   • 6) Some plates move towards each other and so the boundary is destructive/converging/compressional
   • 7) Some plates move away from one another and so the boundary is construstive/diverging/tensional