How does paleomagnetism provide evidence that continents have moved over time?

Paleomagnetism provides evidence for continental movement by acting as a "fossil compass" that records the Earth's magnetic field at the time rocks were formed or deposited. As molten igneous rock cools or sediments lithify, iron-bearing minerals align with the geomagnetic field, preserving the orientation and latitude of their origin.12

Because the magnetic field's lines of force dip steeply at the poles and are parallel to the surface at the Equator, scientists can determine the original latitudinal position of these rocks. When researchers compared the "apparent polar wander paths"—the reconstructed paths of magnetic poles over time—for different continents, they found that the paths did not agree.132

If the continents had remained in fixed positions, all continents would show the same polar wander path. Instead, the divergence of these paths indicates that the continents themselves moved relative to the poles over geologic time. These paths can only be reconciled by shifting the continents into the configurations proposed by the theory of continental drift, providing robust evidence that the landmasses have migrated across the globe.32