The earth's core is known to contain iron. Yet geologists do not regard this as a source of the earth's magnetism. Why ?

Explanation

Iron present in the Earth.s core is in molten form (which is the physical state of iron at high temperatures as of the core) and is not ferromagnetic, as it has a temperature much more than that of the Curie temperature for iron. So, it can not considered as a source of earth.s magnetism.