Geologists can use the magnetic alignment of minerals in rocks to understand plate movements over time by studying the patterns of magnetic minerals in rocks. When rocks form, the minerals within them become aligned with the Earth's magnetic field. This alignment is preserved in the rock as it cools and solidifies. By studying the alignment of these magnetic minerals in rocks, geologists can determine the orientation of the Earth's magnetic field at the time the rock formed.
Over time, the Earth's magnetic field has reversed many times, with the north and south magnetic poles switching places. By studying the alignment of magnetic minerals in rocks of different ages, geologists can determine when these reversals occurred. This information can then be used to understand the movement of tectonic plates over time, as well as the formation and breakup of supercontinents.
For example, geologists can study the alignment of magnetic minerals in rocks on the sea floor to understand the movement of tectonic plates over time. By looking at the patterns of magnetic alignment in these rocks, geologists can determine the direction and rate of movement of the plates and how they have changed over time. This information can be used to understand the formation and breakup of supercontinents, as well as the history of plate tectonics on Earth.