Question

How do rocks on the seafloor record magnetic reversals over time?

Answer 1

the sea floor record the magnetic reversals over time by Iron rich mineral in lava cools. then crystallize finally land record earth magnetic polarity. Evidence suggest that the magnetic field has periodically reversed it polarity in the past. When reverse patches grow to a point that they dominate the rest of the core earth overall magnetic field flips.

Answer 2

When new seafloor is created by upwelling magma at the mid-ocean ridges, the magnetic minerals orient themselves to the magnetic orientation of Earth at the time of their solidification in the rock matrix. Thus, the history of magnetic reversals are recorded in the rock.