sea-floor spreading

/ ˈsiːˌflɔː /

noun

1. a series of processes in which new oceanic lithosphere is created at oceanic ridges, spreads away from the ridges, and returns to the earth's interior along subduction zones Also calledocean floor spreading

sea-floor spreading

1. In the theory of plate tectonics, the process by which new oceanic crust is formed by the convective upwelling of magma at mid-ocean ridges, resulting in the continuous lateral displacement of existing oceanic crust.
2. See more at magnetic reversal

sea floor spreading

1. The process by which new material that lies under the ocean rises and pushes the existing tectonic plates aside, creating new crust as it does so.

Notes

Sea floor spreading is making the Atlantic Ocean wider by a few inches each year.