Convection currents in the mantle, driven by heat transfer, are responsible for the movement of tectonic plates on the Earth’s surface.
The material in the mantle rises towards the surface as a result of heat from the Earth’s core becoming less dense. It sinks back down towards the core when it gets closer to the surface because it cools down and gets denser. This creates a circular motion of material within the mantle known as convection currents.