seafloor 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.
Examples from the web for sea floor spreading
  • He claimed that this process, now called subduction, destroys the surface formed by sea floor spreading.
sea floor spreading in Culture

sea floor spreading definition


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.

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