How does it work?

Sediments everywhere contain low concentrations of uranium, thorium and potassium which produce, over geological time periods, a constant flux of ionising radiation. Both quartz and many feldspar minerals act as dosimeters recording their exposure to this ionizing radiation. After being exposed to radiation these minerals, when stimulated by either heat or light, emit light. This is known as luminescence. The amount of luminescence emitted is proportional to accumulated dose since the minerals were last exposed to heat, e.g. by pot firing or light, e.g. to day-light during sediment transport. With careful measurements luminescence can be used to establish the total amount of accumulated dose since the last resetting event. This when combined with measurement of the present-day annual ionizing dose rate can be used to calculate an age.