The Internal Structure

• • There are 2 types of crust:
  • Continental Crust. This composed of light rock e.g. granite. It ranges from 30-70 km in thickness. It is referred to as SIAL.
  • Oceanic Crust. This is composed of heavy rock e.g. Basalt. It ranges from 3-12 km in thickness. It is referred to as SIMA.
• • The mantle can be divided as follows:
  • Rigid Upper Mantle: This is made up of Rigid rocks (solid). It ranges in thickness from 50 – 100 km. 
  • Lower Mantle: This is made up of semi molten (liquid) rock which is continuously moving. It is up to 2,900 km thick.
• Temperatures in the lower mantle can be up to 4,000 degrees.
• Lithosphere is the name given to the Continental Crust + the Oceanic Crust + the Rigid Upper Mantle.
• Asthenosphere is the name given to the semi-molten part of the mantle.
• Moho is the name given to the boundary between the crust and the mantle.
• • The Core can be divided into 2 layers:
  • The Outer Core is composed of semi molten rock. It consists of mainly iron.
  • The Inner Core is composed of solid rock. It is mainly iron and nickel. Temperatures in the Inner Core can reach 5,000 degrees Celsius.
• The inner core transfers heat to the upper layers. This heat drives the whole tectonic system.