Thermoluminescence dating

A method for estimating when mineral grains were last heated by measuring light emitted as they are heated in the laboratory. The estimate comes from radiation energy accumulated in crystal defects since that heating.

Thermoluminescence: Light emitted by a material when heating releases charge carriers trapped in its crystal structure. Dating measures this signal to estimate the radiation energy stored since the mineral was heated.
Archaeological dating: The use of scientific methods to estimate the ages of human-made objects and archaeological deposits. Thermoluminescence can date fired artifacts whose minerals were heated during manufacture.
Crystal defect: A departure from the regular arrangement of atoms in a crystalline solid. Defects create sites where charge can be trapped until laboratory heating releases it.
Radiocarbon dating: A dating method that estimates the age of once-living material from its remaining carbon-14. It dates organic remains, whereas thermoluminescence dates the last heating of mineral grains.
Electron trap: A defect or impurity site in a solid that can capture and temporarily hold an electron. Electrons trapped after heating store part of the radiation energy that later produces the measured glow.
Pottery: Ceramic vessels and objects made by shaping and firing clay. Firing empties mineral traps, so the accumulated signal can date a pottery object's last firing.
Quartz: A crystalline mineral composed of silicon dioxide, common in rocks and sediments. Quartz grains can store radiation-induced charge and produce thermoluminescence signals.
Potassium-argon dating: A radiometric dating method based on the decay of potassium-40 to argon-40 in minerals. It dates mineral formation or cooling over geological timescales, not an artifact's last firing.
Ionizing radiation: Radiation energetic enough to remove electrons from atoms or molecules, creating charged particles. Radiation from the sample and its surroundings replenishes trapped charge after the last heating.
Bricks: Rectangular construction units commonly made by molding and firing clay. Their firing can reset the luminescence signal, allowing the manufacture date to be estimated.

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