Termoluminescensdatering

Termoluminescensdatering, or thermoluminescence dating, is a geochronology method used to determine the time elapsed since crystalline minerals were last heated or last exposed to sunlight. The technique relies on natural radioactivity in the mineral lattice, which creates electronic traps over time. When the sample is subsequently heated in the laboratory, the trapped electrons are released as light; the emitted luminescence is called thermoluminescence.

The intensity of the thermoluminescent signal is proportional to the accumulated radiation dose since the last heating event. To convert this signal into an age, the equivalent dose (D_e) is determined in the lab, and the age is calculated as age = D_e divided by the annual dose rate (D_rad) from the surrounding environment. The method primarily uses quartz and feldspar minerals and is frequently applied to pottery, burnt stones, ceramics, and sedimentary deposits.

Applications and scope include dating archaeological artifacts when organic material is unavailable for radiocarbon dating, as well as geological and palaeoenvironmental contexts where sediments have been heated or exposed to light before burial. Thermoluminescence dating can cover timescales from thousands to several hundred thousand years, depending on the mineral, dose rate, and moisture history of the environment.

Limitations and uncertainties arise from partial bleaching (incomplete reset of the signal before burial), changes in the radiation environment over time, moisture content, and post-depositional processes. Accurate dating requires careful sample preparation, measurement of the dose rate, and calibration against known-age materials. Thermoluminescence remains complementary to other dating methods and to related techniques such as optically stimulated luminescence dating.