mantle convection

• Earth's structure


  Made up of four different layers, each with distinct characteristics and composition
• Layers of the Earth

  • Crust
  • Mantle
  • Outer Core
  • Inner Core
• Crust


  • Earth's outermost layer, where life exists
• Mantle


  • Made of molten iron and minerals that will still flow under pressure
• Outer Core


  • Composed of liquid iron and nickel
• Inner Core


  • Made up of solid iron and nickel
• What Makes Lithospheric Plates Move?

  1. Convection current is a heat transfer process that involves the movement of energy from one place to another

  2. Convection currents tend to move a fluid, gas particles, or molten rock

  3. Due to differences in densities and temperatures, hot fluid rises and cold fluid sinks
• Mantle Convection Process


  1. Decomposition of radioactive elements causes heat in the interior part of the Earth

  2. Heat moves to the core

  3. Heat slowly rises to the mantle and creates convection current

  4. Lithospheric plates move in the asthenosphere due to the rising and sinking of materials
• Mantle Convection Process


  1. Where convection currents in the mantle are moving upward, new lithosphere forms and the plates move apart (diverge)

  2. Where two plates are converging, one plate will be subducted (pushed down) into the mantle beneath the other
• Mantle Convection Process


  1. Plates move through a combination of pull from the weight of the subducting edge of the plates, and through the outward pushing of an ocean ridge where magma is rising and forming new crust

  2. This creates a circular pattern of rising and sinking water called a convection cell

  3. Heat is continuously flowing outward from Earth's interior, and the transfer of heat from the core to the mantle causes convection in the mantle
• Mantle Convection Process


  1. Mantle material is essentially solid rock, but sufficiently plastic (fluid) to slowly flow as long as a steady force is applied to it

  2. In the process of slab pull, the presence of a heavier subducting plate pulls down the trailing slab into the subduction zone

  3. In a ridge push or gravitational sliding process, the old oceanic crust becomes heavier than the new oceanic crust and sinks because of the weight of the ridge, which pushes down the older oceanic crust towards the trench at the subduction zone