Third, magnetism in rocks can be used to estimate the age of a fossil site. This method uses the orientation of the Earth's magnetic field, which has changed through time, to determine ages for ...

Previously, estimates and hints of the early Earth's magnetic field have come from individual mineral crystals called zircons found within ancient rocks from Western Australia. These had suggested ...

Have you ever played with a magnet and stuck it in a sandy wash? It will pick up lots of black stuff. Some call it black sand; some might think ...