Glossary Archaeological method and dating
Thermoluminescence dating
Also called: TL dating, TL test
A method that dates fired clay by measuring the light it releases when heated, widely used to test whether a pot or terracotta is ancient.
Minerals in clay trap energy from natural radiation over time. Firing empties the traps, so the clock starts when a pot or figurine was fired. Heating a small drilled sample in the laboratory releases the stored energy as light, and the amount of light indicates how long ago the last firing took place. The dates are broad, often with errors of several centuries.
Archaeologists date sites by radiocarbon more often, but the antiquities trade relies on thermoluminescence to check authenticity: a TL test can show that a terracotta was fired in antiquity, though it says nothing about restoration or where the piece was found. It only works on fired material, so no comparable test exists for limestone sculpture or stone plank figures.
Related terms
- Radiocarbon dating
A scientific method that dates once-living material such as charcoal, seeds and bone by measuring the decay of the carbon-14 it contains.
- Archaeometry
The use of physical and chemical science to analyse archaeological materials: their date, composition, source and manufacturing technique.
- Unprovenanced
Describes an object whose find-spot is unknown, and often whose earlier ownership history is undocumented as well.