Answer:
Sea floor spreading
Step-by-step explanation:
The process responsible for creating magnetic changes along the mid-ocean ridges. Sea floor spreading entails the movement of the lithosphere over the weak and fluid asthenosphere. At the spreading center new oceanic crust is created.
The earth is surrounded by a magnetic field. Magnetic minerals in fresh magma orients in the direction of prevalent magnetic field when they begin to cool and solidify.
Due to changes in the magnetic field direction and the upwelling of new magma, the magnetic patterns in a rock changes.