Seafloor spreading is a geological process that occurs at mid-ocean ridges, where tectonic plates move apart. As these plates separate, magma from the Earth's mantle rises to fill the gap, creating new oceanic crust. This process continuously adds material to the ocean floor, pushing older crust away from the ridge. As the seafloor spreads, it can lead to the formation of features like mountain ranges and ocean basins. The movement of tectonic plates is driven by forces such as convection currents in the mantle, which help shape the Earth's surface over millions of years.