Osl dating ppt
As a result, there is no upper date limit set by the sensitivity of the method itself, although other factors may limit the method's feasibility.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.
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.
The term luminescence refers to the energy emitted as light from minerals such as quartz and feldspar after they've been exposed to an ionizing radiation of some sort.
Minerals, in fact, everything in 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.
This technique, as thermoluminescence, was originally developed in the 1950s and 1960s to date fired archaeological materials, like ceramics (Aitken, 1985).
Ensuing research in the 1970s documented that marine and other sediments with a prior sunlight exposure of hours to days were suitable for thermoluminescence dating (Wintle and Huntley, 1980).