The light energy released is derived from electron displacements within the crystal lattice of such a substance caused by previous exposure to high-energy radiation.Heating the substance at temperatures of about 450° C (842° F) and higher enables the trapped electrons to return to their normal positions, resulting in the release of energy.
The author discusses the limitations of the method as well as its advantages, the dating of 2 Near Eastern Palaeolithic sites, Rosh Ein Mor and Jerf al-Ajla, being used as examples.
Richter's conclusions For any chronometric dating of an archaeological site the accuracy is most dependent on the relationship of the sample to the archaeological event (association), but it is also dependent on environment of the deposition and the quality of the samples.
Archaeological dating is very important for Mexico taking into account the abundance of ancient ceramics existing through the country.
The results are reported of studying three sherds from the archaeological site in Calixtlahuaca, Mexico, where the Matlazinca culture blossomed before the Spanish arrived in America.
The underlying assumptions of this method of dating are not considered to be trivial, though the basic principle of TL dating are simple.
The external dose rate is one of the major sources of error, contributing to the denominator of the age formula to a varying degree, therefore the amount of its influence on the dating result is variable.
The average values of paleodose obtained were 8.46 ± 0.27 Gy and 3.62 ± 0.13 Gy for two of the samples studied; the annual dose rates were 5.55 ± 0.20 m Gy and 4.20 ± 0.30 m Gy.
Taking into account these results, the ages of these two ceramic samples were 1520 ± 90 and 870 ± 80 years which agree well with the historical data for the site.
It is necessary to take great care in the evaluation of TL dates and when publishing the results of dating certain standards need to be met.
Included among these are the presentation of glow curves, heating plateaus and Dplateaus, growth curve(s) ( including correction for supralinearity) and the determination of the alpha sensitivity of each sample, and it is required that equal care be taken in the evaluation of parameters that are prone to variation over time.
To establish the elapsed time since the last time the object, such as a flint, has been heated, dating by thermoluminescence is a useful tool.