What is archaeomagnetism dating?

Question

Brief explanation please.

Answer 1

Periodically, the Earth's magnetic field reverses itself. That is, the north and south poles switch places. Certain materials are affected by Earth's magnetic field (iron particles, for starters), and so will line up with it in a particular way while they are mobile. Eventually they get covered up, and so do not switch the next time the magnetic field does. If we know when the magnetic field has changed, we can get a good idea of when these materials became immobile, or at least the latest date that they did.

EDIT: Right, forgot about the heating, good catch.

Answer 2

I would agree with the Ry guy except to add that the magnetic poles get lined up as a magnetic material cools.  It has to get over a thousand degrees or so.  There may be a pot for example that has magnetite in it.  It is fired and then when it cools, it aligns itself with the magnetic field.  There is no remnant magnetization that is measurable simply by where it is last mobile to my knowledge.