Luminescence tutorial (next: OSL)

Luminescence geochronology is based on the time-dependent dosimetric properties of silicate minerals, predominately feldspar and quartz. The technique has been used to date sediments usually < 200 ka old that received sunlight exposure prior to deposition.
(Hashimoto et al., 1986)Exposing sediment to sunlight for hours (e.g. Godfrey-Smith et al., 1988) or heating to >300 ºC eliminates most of the previously acquired luminescence from mineral grains. After the sediment is buried and shielded from further light exposure ionizing radiation from the decay of naturally occurring radioisotopes of U, Th, and K produces free electrons which are subsequently trapped in crystallographic charge defects in silicate minerals. Excitation of minerals by heat or light yields in recombination of stored-charge that results in luminescence emissions. The intensity of the luminescence is calibrated in the laboratory to yield an equivalent dose (De, measured in grays (Gy); 100 rads = 1 gray), which is divided by an estimate of the radioactivity that the sample received during burial (dose rate, Dr) to render a luminescence age.