Magnetic Polarity Evidence for Continental Drift

After Alfred Wegener proposed continental drift, scientists struggled to explain how continents moved.

A key breakthrough came from studying Earth's magnetic field, which extends from pole to pole and affects iron-rich minerals like magnetite.

As lava cools, tiny magnetite crystals within the rock align with Earth's magnetic field, acting as compasses pointing to the North Pole.

Using magnetometers, scientists discovered that older rocks pointed to different locations than today's magnetic north, suggesting that continents had shifted over time.

On the same continent, rocks of different ages point in different directions, while rocks of the same age from different continents also point in various directions.

If the continents are in fixed locations, all rocks of the same age should point to the same location, but they do not, indicating continental shift.

Geologists reconstructed past continental positions based on the orientation in which magnetite crystals initially formed, showing alignment with the current north magnetic pole.

Initially, this created the illusion of a shifting magnetic pole, but instead, it confirmed a phenomenon called apparent polar wander, supporting the theory of continental drift.