Magnetic Stripe

A diagram of white and orange stripes that represent magnetic polarity on the seafloor.
(NOAA)

A simplified diagram of magnetic stripe patterns at a mid-ocean ridge. The central black line marks the spreading center. When new minerals form there, they lock in the current direction of Earth’s magnetic field, either “normal” or “reversed.” As new crust forms, older crust is pushed outward, away from the spreading center.