Which type of plate boundary creates new oceanic crust at mid-ocean ridges?

A divergent boundary creates new oceanic crust as tectonic plates move apart at mid-ocean ridges.

When plates separate, hot mantle material rises beneath the gap. Reduced pressure allows some of the mantle to melt, producing basaltic magma. The magma cools to form new oceanic lithosphere, while older seafloor moves away from the ridge. This process is called seafloor spreading.

The global mid-ocean ridge system extends for roughly 65,000 kilometres through the ocean basins. The Mid-Atlantic Ridge is a well-known example, separating the North American and Eurasian plates in the north and the South American and African plates farther south. Much of the ridge lies underwater, although Iceland exposes a section above sea level.

Divergent boundaries can also occur within continents, where stretching creates rift valleys. They differ from convergent boundaries, where plates collide, and transform boundaries, where plates slide laterally past one another. New crust at ridges is balanced by old oceanic crust being recycled into the mantle at subduction zones.