Luminescence Research Laboratory
Dating
Luminescence dating depends on the ability of minerals to store energy in the form of trapped charge carriers when exposed to ionising radiation. Stimulation of the system, by heat in the case of thermoluminescence (TL), or by light in the case of photo-stimulated luminescence (PSL), or optically stimulated luminescence (OSL).
Following an initial zeroing event, for example heating of ceramics and burnt stones, or optical bleaching of certain classes of sediments, the system acquires an increasing luminescence signal in response to exposure to background sources of ionising radiation. Luminescence dating is based on quantifying both the radiation dose received by a sample since its zeroing event, and the dose rate which it has experienced during the accumulation period. The technique can be applied to a wide variety of heated materials, including archaeological ceramics, burnt stones, burnt flints, and contact-heated soils and sediments associated with archaeological or natural events. Optically bleached materials of interest to quaternary science include aeolian, fluvial, alluvial, and marine sediments.
Luminescence dating can be applied to the age range from present to approximately 500,000 years, thus spanning critical time-scales for human development and quaternary landscape formation. Precision varies from ±3-10% of age for heated materials and ±5-20 % for sediments. Luminescence dating techniques can also be used for dose reconstruction, following accidental exposure to ionising radiation, and to assess thermal exposure for example of concrete structures subject to fire damage.
