How does the ocean floor keep track of magnetic fields?

Question

Question 4 options:

There are magnets in the ocean floor

All rocks act like magnets

Basalt is iron-rich and responds to magnetic fields

Being underwater makes the rocks respond to magnetic fields.

Answer 1

The correct option is:

Basalt is iron-rich and responds to magnetic fields.

When basalt (a type of rock that forms at mid-ocean ridges) cools, the iron minerals within it align according to the Earth's magnetic field at the time of cooling. This process allows scientists to study past magnetic field reversals and the history of seafloor spreading.