What does the sinking of cold ocean lithosphere drive the motions of mantle convection through?

The sinking of cold ocean lithosphere drives mantle convection through a process called slab pull. As the dense, cold lithosphere subducts into the mantle, it creates a gravitational pull that facilitates the movement of the surrounding, hotter mantle material. This movement helps to drive the convection currents within the mantle, contributing to tectonic plate dynamics and the recycling of materials within the Earth's interior. The interaction between the descending lithosphere and the surrounding mantle influences the overall behavior of plate tectonics.