Luminescence dating method
After deposition of the grains and burial under new sediment, their latent luminescence signal accumulates again because they absorb the natural ionising radiation that is emitted by the surrounding sediment. The age that is determined corresponds to the time span between the removal of the luminescence signal by sunlight just before deposition and the removal of the newly accumulated palaeodose by thermal or optical stimulation in the laboratory.
Stimulation by heat is called thermoluminescence (TL) and stimulation by light, optical stimulated luminescence (OSL).
A certain percent of the freed electrons become trapped in defects or holes in the crystal lattice of the quartz sand grain (referred to as luminescent centers) and accumulate over time (Aitken, 1998).
In our laboratory, these sediments are exposed to an external stimulus (blue-green light) and the trapped electrons are released.
Once this sediment is deposited and subsequently buried, it is removed from light and is exposed to low levels of natural radiation in the surrounding sediment.
Through geologic time, quartz minerals accumulate a luminescence signal as ionizing radiation excites electrons within parent nuclei in the crystal lattice.
OSL has two major variants: the infrared stimulated luminescence (IRSL) and the blue light stimulated luminescence (BLSL). (1998) The late Pleistocene loess deposits of eastern Belgium: new TL age determinations.
six Elsec7286 low-level alpha counters Ris GM-25-5 low-level beta GM multicounter system low-background extended-energy range HPGe gamma spectrometer portable gamma spectrometer (Canberra portable plus model 1150) and 3x3 inch. This focus wil not change during the coming years 2003-2004.. (1998) Bijdrage tot de studie van de thermoluminescentie-dateringsmethode en toepassing op archeologisch keramiek en eolische sedimenten. Na I(Tl)detector) Chronostratigraphy and luminescence dating of the aeolian deposits of the western Chinese loess plateau: a contribution to the investigation of the terrestrial record of the Quaternary climate oscillations. (defended at the Laboratory of analytical chemistry) Munyikwa K. (2002) - A comparison of methods for the annual radiation dose determination in the luminescence dating of loess sediment. (2000) - Observations on the thermoluminescence signal induced by alpha irradiation. (1998) The stratigraphy, sedimentology and thermoluminescence dating of the Upper Kalahari beds of western Zimbabwe. (in preparation) A critical comparison and evaluation of methods for determination of the annual radiation dose in luminescence dating of sediments. - "Investigations on the origin of the equivalent dose distributions in Dutch coversand" Radiation Measurements. M., De Corte F., Van den haute P., Fuchs M., Murray A. Exploring the methodology of optically stimulated luminescence dating and comparison of optical and 14C ages of Late Weichselian coversands in the southern Netherlands. Nuclear Instruments and Methods in Physics Research A 490, 598-613. A curve is generated for each aliquot (subsample), multiple aliquots are needed to obtain an accurate De. J., 1998, An introduction to optical dating: The dating of Quaternary sediments by the use of photon-stimulated luminescence: Oxford, University Press, 267 p. A dating method based on single aliquot luminescence dose determination was applied to quartz and feldspars from heated archaeological materials.