Final answer:
Magnetic reversals are important for understanding landmass evolution and continental movements. Solidifying rocks preserve the Earth's magnetic field and by studying them, geologists can determine past pole locations and track continent movement. The spreading rate at mid-ocean ridges gives historical information about the Earth's magnetic field.
Step-by-step explanation:
Magnetic reversals are a key tool in understanding the evolution of landmasses and the movements of continents. When rocks cool and solidify from molten material, they preserve the Earth's magnetic field at the time of their formation. By studying the magnetic orientation of rocks, geologists can determine the past locations of the Earth's magnetic poles and track the movement of continents over time. The knowledge of the spreading rate at mid-ocean ridges can be used to give the historical record of the Earth's magnetic field, providing insights into plate tectonics and continental drift.