Luminescence dating techniques regional dating sites
Photon-stimulated luminescence (PSL) is emitted when minerals are exposed to visible or infrared wavelengths of light, and radioluminescence (RL) is emitted during mineral exposure to nuclear radiation (e.g., gamma rays).
Other terms for PSL dating are optical dating or OSL dating.
OSL is also less commonly referred to as optical dating, photon stimulated luminescence dating or photoluminescence dating..
Luminescence dating methods are based on the ability of some mineral grains to absorb and store energy from environmental ionizing radiation emanating from the immediate surroundings of the mineral grains as well as from cosmic radiation.
TL dating is a matter of comparing the energy stored in a crystal to what "ought" to be there, thereby coming up with a date-of-last-heated.
In the same way, more or less, OSL (optically stimulated luminescence) dating measures the last time an object was exposed to sunlight.
Heating the mineral (or exposure to light) releases electrons, and produces a flash of light, setting the clock to 0 (maybe only partial).
Thereafter, luminescence accumulation is proportional to age.
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.The dating range is dependent on the nature and state of conservation of the sample and the surrounding environment but is between a few thousands and a couple of million years.Since, ESR dating is best and most commonly applied to tooth enamel in archaeology PRINCIPAL: energy trapped in crystal imperfections depends on dose rate and time. Uranium atom produces high energy particles which leave straight "tracks" (10 - 20 µm) in glassy material The tracks are trails of destruction in the crystal lattice formed by particles emitted during spontaneous fission of 238U.Quartz, feldspar, zircon, and calcite are the most important minerals for luminescence geochronology, and they can produce several different types of luminescence.Thermally stimulated luminescence (or thermoluminescence, TL) is a cold light that is emitted upon heating minerals to a temperature (e.g., 450 °C) below that of incandescence (Aitken, ).
Through optical filters the PSL signal is observed at shorter wavelengths (higher photon energies) than the stimulating light (“anti-Stokes” emission).