Geo

• The three main layers of the Earth

  • The Crust
  • The mantle
  • The Core (outer core, inner core)
• The Crust


  • The outer most layer of the Earth
  • The lightest rocks are found in the crust
  • There are two types: Continental and Oceanic
• Continental Crust


  • Made up of silica and aluminium (SIAL)
  • Thick (up to 70 km)
  • Lighter than oceanic crust
  • Main rock type is granite
• Oceanic Crust


  • Made up of silica and magnesium (SIMA)
  • Continuous around the entire Earth's surface
  • Thin (3 km to 10 km)
  • Heavier than continental crust
  • Main rock type is basalt
• Continental Drift


  The theory that the continents had slowly drifted apart from a super continent into the world that we know today
• Evidence of Continental Drift


  • The fit of the continents - the 'jigsaw' effect
  • Rocks of similar type and age found at the edges of continents
  • Similar plant and animal fossils found in neighbouring continents that are now separated by water
• Plate Tectonics


  The theory that the Earth's crust/outer shell is divided into a series of plate-like structures that 'float' on the semi-molten mantle layer below them
• Types of Plates


  • Oceanic
  • Continental
• Directions of Plate Movement

  • Towards each other
  • Away from each other
  • Parallel alongside each other
• Types of Plate Boundaries

  • Convergent/Destructive
  • Divergent/Constructive
  • Transform/Conservative
• Convergent Plate Boundary


  • Plates move towards each other
  • Results in earthquakes, volcanoes, folding
• Divergent Plate Boundary


  • Plates move away from each other
  • Results in oceanic ridges, rift valleys, volcanic islands
• Transform Plate Boundary


  • Plates move parallel alongside each other
  • Results in fold mountains