sea-floor spreading

noun

1. a process in which new ocean floor is created as molten material from the earth’s mantle rises in margins between plates or ridges and spreads out.

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 zonesAlso called: ocean 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. See more at magnetic reversal.