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Why are ocean basins temporary features over geologic time?

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World map highlighting major features of the ocean basins, including trenches, ridges, basins, and plateaus labeled throughout the Pacific, Atlantic, Indian, Southern, and Arctic Oceans. Continents are shown with shaded terrain, and prominent undersea features such as the Mid-Atlantic Ridge, Mariana Trench, and Kerguelen Plateau are marked across the map. — ocean basin Major features of the ocean basins.

Ocean basins are considered temporary features over geologic time because they are constantly being created, reshaped, and destroyed by the process of plate tectonics.1

The Earth's lithosphere is composed of rigid plates in continual motion. New oceanic crust is formed at spreading centres along oceanic ridges, where molten rock from the mantle rises to fill the gap between diverging plates. Conversely, old oceanic crust is destroyed at subduction zones, where plates converge and one slides beneath another into the mantle to be melted.12

Because of this ongoing cycle of creation and destruction, the seafloor is relatively young; the oldest segments are only about 200 million years old, a small fraction of Earth's 4.6-billion-year history. This dynamic process, often described as the Wilson cycle, means that ocean basins open, widen, and eventually close as continents drift and collide, ensuring that the geography of the ocean floor is never permanent.12345