How do magnetic studies provide evidence for continental drift?

Magnetic studies provide critical evidence for continental drift and the broader theory of plate tectonics through two primary mechanisms:

Paleomagnetism and Polar Wandering

As igneous and sedimentary rocks form, iron-bearing minerals align with Earth’s magnetic field, preserving a record of their latitude at the time of formation. By analyzing these orientations, geologists can track the movement of continents over geologic time. Crucially, "polar-wandering curves"—which map the apparent path of magnetic poles relative to a specific continent—do not align when compared across different continents. This discrepancy provides direct evidence that the continents have moved relative to one another.12

Marine Magnetic Anomalies

The Vine-Matthews-Morley hypothesis explains that as new oceanic crust forms at spreading centres, it records periodic reversals of Earth's magnetic field. This creates symmetric, linear magnetic patterns on either side of ridge crests. These anomalies confirm seafloor spreading, demonstrating that the seafloor—and the continents attached to it—are in constant motion.34