Luminescence dating using single aliquots: Methods and applications

Luminescence dating of sediments requires the determination of two quantities: the equivalent radiation dose to which the sample has been exposed since the event that is being dated; and the radiation dose to which it is exposed per year. Dividing one quantity by the other gives the age of the sample. Over the past four years a new group of methods has been developed for the determination of the equivalent dose of a sample. These are collectively known as 'single aliquot' methods since, in contrast to standard luminescence methods, all the measurements are made on one aliquot of the sample. This has considerable practical advantages in terms of precision and the speed of analysis. In addition to being an alternative to standard methods of luminescence dating, the new methods are able to identify poorly bleached samples and to work on small samples which could not practically be analysed by conventional methods. The most exciting prospect is the ability to date individual sediment grains, between about 100 and 300 μm in diameter. The different single aliquot methods are described and examples given of their application to specific sites.