Why does the magnetic field of ancient rocks provide evidence of moving tectonic plates?

Question

a
Paleomagnetic activity can help detect the age of each rock in the rock layers
b
Large amounts of magnetic fields provide the recording data, like we use in magnetic tape today, to track the motion of the plates
c
Each rock is created with a unique direction of its magnetic field. Finding rocks in the layers that have different magnetic fields it must have been moved their by tectonic plates
d
Magnetic fields grow in intensity as they are forced to move through the Earth's magnetic field, so detecting higher than expected magnetic strength of rocks means they must have moved

Answer 1

The correct answer is:

c Each rock is created with a unique direction of its magnetic field. Finding rocks in the layers that have different magnetic fields must have been moved by tectonic plates.

This is because as magma cools to form igneous rocks, the iron minerals within align with the Earth's magnetic field at that time. When the rocks are later formed into sedimentary layers or altered by tectonic processes, any changes in the orientation of those rocks can indicate that they have been moved due to tectonic activity. By studying the magnetic orientation in these ancient rocks, scientists can infer the historical movement of tectonic plates.