Electron Spin Resonance Dating falls into the group of dating methods that uses radiation exposure to date many materials found at archaeological sites. It is also known as a Radiometric Dating Method. This technique is mostly used to date minerals.It has been used to date such things as sedimentary quartz, fossilized teeth, flint, and calcium carbonate in limestone, coral and egg shells.

This method works by using radiation to cause electrons to separate from the atoms. These electrons then become trapped in the crystal lattice of minerals. This changes the magnetic field of the material at a rate that is predictable, allowing it to be used to date an item. It can be used to date when mineralization, sedimentation, or the last heating of minerals took place. It is often used to date quartz from meteorite strikes, and places where earthquake activity has taken place.

Unlike the other two methods of dating by radiation exposure, Thermoluminescence (TL), and Optically Stimulated Luminescence (OSL), Electron Spin Resonance dating can be repeated a number of times. This is because it is the only method that detects the paramagnetic centers and it does not destroy these centers when the measurement is made. Electron Spin Resonance dating is relatively new, some still consider it an experimental dating technique and is often used in combination with another dating method.

Bibliography

Electron Spin Resonance Dating of Quartz and Carbonates http://www.science.mcmaster.ca/geo/research/age/dating.htm

The Record of Time: Chronometric Dating Techniques: Part II, 

Electron Spin Resonance, http://www.dal.ca/~digs/esr1.htm 

Matt Lutgen