How does a magnetic record is created as the sea floor spreads?

As the sea floor spreads, magma rises from the Earth's mantle at mid-ocean ridges, creating new oceanic crust. This molten rock contains iron-rich minerals that align with the Earth's magnetic field as it cools and solidifies. When the magma solidifies, it records the direction and intensity of the magnetic field at that time, creating a magnetic signature. Over time, as the sea floor continues to spread, these signatures form symmetrical patterns of magnetic stripes on either side of the ridge, providing evidence of plate tectonics and Earth's magnetic reversals.