Ocean basin formation

Ocean basins form through the movement of Earth’s tectonic plates. When plates diverge or pull apart, magma rises from below the surface, creating new ocean floor — this happens at mid-ocean ridges. Conversely, plates can also converge, causing one plate to sink beneath another in a process called subduction, which deepens ocean trenches. Over millions of years, these movements reshape and enlarge ocean basins, forming the extensive areas we see today. This continuous process of rifting, spreading, and subduction drives the dynamic evolution of ocean basins across Earth’s surface.