what is one reason we have stripes of alternating magnetism on the ocean floor?

Question

magnetic direction of rock changes as earths magnetic poles drift and reverse
plates move as new rock forms, which causes magnetic direction to skew away from normal
rock is constantly being destroyed at the mid-ocean ridge on the ocean floor
minerals in magma match the magnetic direction present on earth when it hardens into rock

Answer 1

The correct reason for the stripes of alternating magnetism on the ocean floor is:

Minerals in magma match the magnetic direction present on Earth when it hardens into rock.

This phenomenon is known as magnetic striping and occurs due to the process of seafloor spreading at mid-ocean ridges, where new magma rises and creates new oceanic crust. As the magma cools and solidifies, the iron-bearing minerals within it align with the Earth's magnetic field at that time, preserving a record of the magnetic direction. When the Earth's magnetic field reverses, the new rock that forms will have a different magnetic orientation, resulting in the alternating patterns seen on the ocean floor.