Convection: The method of heat transfer known as convection is believed to be the fundamental process underlying the movement of plates. Convection transfers energy in a fluid by the movement of particles in a roughly circular motion. For example, convection is the main process used to heat water on a stove. It is also a major factor in the movement of air currents. Convection is the thought to be the main process distributing heat in the Earth’s mantle.

Forces Driving Plate Tectonics: How exactly does convection determine the motion of plates? Scientists believe that there are a number of forces related to convection that play a direct role in the movement of plates. Three of these are slab pull, slab suction, and ridge push.

• Slab Pull: Slab pull refers to the sinking, or subduction, of cold, dense, oceanic lithosphere slabs at trenches. These sinking slabs serve to pull the rest of the plate along behind them. Slab pull is believed to be the dominant force acting on tectonic plates.


• Slab Suction: Friction between plates in a subduction zone will result in a downward convection flow under both interacting plates. This will cause both plates to move toward the ocean trench. This force is called slab suction.


• Ridge Push: Ridge push refers to the cooling and sinking of new oceanic crust after it is formed at mid-oceanic ridges. This new crust gets denser with age causing it to sink as it slowly moves away from the original point of formation at the center of the mid-oceanic ridge. This material is, in effect, sliding downhill as a result of gravity.