Seafloor Spreading Hypothesis
Mantle material is extruded along mid-ocean ridges and large rifts and fills the rift valleys to form new oceanic crust, and the mantle flows away from the ridge, so the seafloor continues to expand. After a long period of drifting and expansion, the oceanic crust then sinks into the mantle in the Benioff zone. This cycle repeats, causing the oceanic lithosphere to continue to grow and be consumed, and this process keep refreshing continually. The discovery of the striped magnetic symmetry at mid-ocean ridges and the younger age of oceanic lithosphere than the continental lithosphere substantiated the seafloor spreading hypothesis and the wire magnetic recording transfer model. The seafloor spreading hypothesis greatly facilitated the development of the continental drift theory and paved the way for establishing and laying a theoretical foundation for plate tectonics theory because it provided the dynamic mechanism for continental drift.