restless Earth

Structure of the world
1. Inner core= solid Iron + Nickel. 15,000 degrees
  1. Outer core= liquid layer Nickel + Iron
    1. Mantle= semi molten rock. 4000 degrees. The thickest layer- makes up half the earth- about 2900 Km thick
      1. crust= solid, made up of plates- thinnest layer- about 20 Km
Continental drift
1. Evidence
  1. Plates fit together. Africa+ south America
  2. Matching fossils different continents
2. Wegener
3. Pangaea
  1. Continents were joined together
4. Explanation
  1. molten rock heated by earths core
    1. rises towards crust
      1. cools sinks back down again
        process= convection current
  2. plates floating on mantle
  3. convection currents in liquid mantle
    1. Drag floating plates as they circulate
Plate boundaries
1. constructive
  1. Formations
    1. shield volcanoe
    2. Earthquakes
  2. 2 plates move apart. magma fills the gap
2. conservative
  1. formations
    1. Earthquake
  2. plates scrape past each other travelling opposite directions/same direction different speeds
3. Destructive
  1. oceanic +continental plate collide. Oceanic plate sub ducted under continental plate
  2. formations
    1. composite volcanoes
    2. ocean trenches
    3. earthquakes
types of plate
1. Oceanic
  1. Heavy
  2. Less thick
  3. dense
2. Continental
  1. thicker
  2. light not dense

Resumo de Recurso

	Criado por chapel.jacquesel quase 9 anos atrás