Seafloor Spreading
D2. Hydrography, tides, waves, bathymetry and marine geologyDefinition
Process by which new oceanic crust forms at mid-ocean ridges.
Seafloor spreading is the process by which new oceanic crust is created at mid-ocean ridges and carried away symmetrically as plates diverge. As lava cools through the Curie temperature it locks in the prevailing geomagnetic polarity, so reversals of Earth’s field print symmetric magnetic stripes on either side of the axis; matching them to the reversal timescale dates the crust and measures spreading rate. The hypothesis (Hess, Dietz) confirmed plate tectonics.