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Two forms of luminescence dating are used by archaeologists to date events in the past: thermoluminescence (TL) or thermally stimulated luminescence (TSL), which measures energy emitted after an object has been exposed to temperatures between 400 and 500°C; and optically stimulated luminescence (OSL), which measures energy emitted after an object has been exposed to daylight.
To put it simply, certain minerals (quartz, feldspar, and calcite), store energy from the sun at a known rate.
The energy released by stimulating the crystals is expressed in light (luminescence).
The intensity of blue, green or infrared light that is created when an object is stimulated is proportional to the number of electrons stored in the mineral's structure and, in turn, those light units are converted to dose units.
The possibility of making use of TL stored in a mineral or pottery sample was first proposed by chemist Farrington Daniels in the 1950s. The potential of using thermoluminescence to date buried soils developed on colluvial and fluvial sediments from Utah and Colorado, U. Where De is the laboratory beta dose that induces the same luminescence intensity in the sample emitted by the natural sample, and DT is the annual dose rate comprised of several components of radiation that arise in the decay of natural radioactive elements.Artifacts which can be dated using these methods include ceramics, burned lithics, burned bricks and soil from hearths (TL), and unburned stone surfaces that were exposed to light and then buried (OSL).The two-phase research project entailed collecting tiny (less than a millimetre squared) quantities of pigment from the rock painting and then analysing these samples to determine which art should be sampled for AMS radiocarbon dating.The samples that contained the most carbon-black (and thus most likely to reveal dates) were then radiocarbon dated.
Minerals—and, in fact, everything on our planet—are exposed to cosmic radiation: luminescence dating takes advantage of the fact that certain minerals both collect and release energy from that radiation under specific conditions.