Explain sea-floor spreading.
As the oceanic plates spread, mantle material moves up into the void and forms a solid mostly basaltic plate. It is theorized that heat from the liquid outer core powers convection currents in the solid but plastic mantle. These convection currents move in giant circles and push the plates above them. As the currents move upward, they also provide fresh magma to fill in the voids of the spreading plates.
Sea-floor spreading occurs at two diverging plate boundaries. Sea-floor spreading results in the Mid-Ocean Ridge. The Mid-Ocean Ridge is created when two diverging plates have allowed magma from the earth’s interior to push through the cracks between these plates. The new magma pushes old and hardened rock that was once magma, out of the way, making a ripple like mountain range in the deepest parts of the ocean. This process is called sea-floor spreading.
