Thermoluminescence dating range
Luminescence dating is particularly appropriate when radiocarbon dating is not possible (either where no suitable material is available or for ages beyond the radiocarbon age limit) or for applications affected by radiocarbon plateau effects (e.g.
These slowly decay over time and the ionizing radiation they produce is absorbed by mineral grains in the sediments such as quartz and potassium feldspar.The Moche or Mochica are perhaps best known for their ceramic art: their pots include life-sized portrait heads of individuals and three-dimensional representations of animals and people.Many of these pots, looted long ago from Moche sites, can be found in museums throughout the world: not much more about the context from where they were stolen is known.Stimulating these mineral grains using either light (blue or green for OSL; infrared for IRSL) or heat (for TL) causes a luminescence signal to be emitted as the stored unstable electron energy is released, the intensity of which varies depending on the amount of radiation absorbed during burial and specific properties of the mineral.Most luminescence dating methods rely on the assumption that the mineral grains were sufficiently "bleached" at the time of the event being dated.The error limits on the dates obtained are typically in the range of 5 to 10%.
Our standard cost for OSL dating is £550 VAT per sample but prices can vary depending on the nature and number of samples (see our schedule of charges).
Should I be concerned about artificial irradiation? If the radioactivity of the pottery itself, and its surroundings, is measured, the dose rate, or annual increment of dose, may be computed.
Warning about fakes using ancient materials What about airport x-rays and radiography? Thus, when one measures dose in pottery, it is the dose accumulated since it was fired, unless there was a subsequent reheating.
The particular advantage of luminescence dating is that the method provides a date for the archaeological artefact or deposit itself, rather than for organic material in assumed association.
In the case of OSL sediment dating, suitable material (sand or silt-sized grains of quartz and feldspar) is usually available ubiquitously throughout the site.
When pottery is fired, it loses all its previously acquired TL, and on cooling the TL begins again to build up.