A dating method that measures the amount of light released when an object is heated. Thermoluminescence, or TL, has been used since the 1950s to determine the approximated firing date of pottery and burnt silicate materials. TL has a wide dating range; it has been used to date ceramics from a few hundred years old to geologic formations that are half a million years old. The technique measures the small amount of energy that continually builds up in the mineral crystal lattice. When heated, this energy is released as a burst of light. The intensity of the light is proportional to the amount of energy, which in turn corresponds to the length of accumulation time. Thus the time can be approximated for original original firing date. Recently new techniques (optically stimulated luminescence dating) using lasers and sensitive detectors have been used to improve the light detection. Samples require about 100 milligram and the sample collection and handling step is critical. The accuracy of the technique is about 10%. The rate of energy accumulation depends on the amount of background radiation to which the object has been exposed. Thus, preliminary X-ray or gamma radiography examination of the object can increase the amount of accumulated energy and thus give erroneous dating result.
Synonyms and Related Terms
TL; optically stimulated luminescence dating; OSL; Thermolumineszenzdatierung (Deut.); datation par thermoluminescence (Fr.); termoluminescenza (It.)
- Aitken, M.J., Thermoluminescence Dating, Academic Press, London (1985)
- C. Furetta, Questions and answers on Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL), World scientific publishing, Singapore (2008)
- I. Liritzis, A. K. Singhvi, J. K. Feathers, G. A. Wagner, A. Kadereit, N. Zacharias & S.H. Li, Luminescence dating in archaeology, anthropology, and geoarchaeology: An Overview, Springer (2013)
Sources Checked for Data in Record
- Aitken, M.J., Introduction to Optical Dating, Oxford University Press (1998)
° Roy Switzur "Dating Techniques" Building Conservation Directory 2001: Link (lists analysis labs in England)
- Caring for your Collections, Arthur W Schulz (ed.), Harry N. Abrams, Inc. , New York, 1992
- External source or communication Comment: Tom Chase, CoOL DISTLIST, 5/1/01 - "X-radiography can affect the TL date. In the case of bronze objects with clay cores, I remember Sstuart Fleming saying that one normal radiograph adds about 5 years....."
- Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000