Restless Earth intro

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  • Restless Earth Intro
    • Structure of the earth
      • Crust
        • Outer layer- thin slit into plates
        • Between 5-60km thick, cont. thicker
        • Oceanic- denser, below water
        • Continental- less dense, made from granite
      • Mantel
        • Dense, mosty solid layer between the outer core and crust. Properties of solid but can flow slowly
        • 80% of earths volume, 2900km thick
        • CAn reach 3800c
      • Core
        • Made from liquid and nickel and iron, centre of earth very hot- 4300c
        • Innercore- solid, outercore- liquid
        • Radius is half of the earths radius
    • Why do plates move?
      • Heat from core melts rock
        • Melted rock expands, its density is reduced and rises (convection)
          • Rising liquid will cool, contract and sink
            • If liquid reaches the surface it causes plates to move
              • Convection currents- movement of a liquid due to a change in tep.
    • Oceanic vs continental
      • Oceanic
        • Newer- less than 200 mill years old
        • 5-10km -thinner
        • Basalt- can sink
        • Can be renewed or destroyed
      • Continental
        • Older- over 1500 mill yrs
        • 20-65km- thicker
        • Granite- less dense, cannot sink
        • Cannot be renewed or destroyed
    • Plate margins
      • Destructive- converging (towards)
        • Subduction and collision
          • Collision - continental and continental
            • Resists subducts, buckles up to create mountains
        • Continental and oceanic
      • Constructive- diverging (apart)
        • Oceanic and oceanic
        • Gap forms magma rises
      • Conservative-sideways
        • Oceanic and continental
        • Stuck- different speed and angles, causes friction
        • Pressure builds, when released- shock waves

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