In the authors studies each sample was dated by all 3 methods whereas the Europeans analyses employed only the Regeneration technique.This work presents results from loess sections in Mississippi, Illinois and Alaska.To put it simply, certain minerals (quartz, feldspar, and calcite), store energy from the sun at a known rate.
These TL dates are not only the oldest yet proposed for Aboriginal occupation but also may mark the time of initial human arrival on the Australian continent.
Luminescence dating (including thermoluminescence and optically stimulated luminescence) is a type of dating methodology that measures the amount of light emitted from energy stored in certain rock types and derived soils to obtain an absolute date for a specific event that occurred in the past.
Heating these crystals (such as when a pottery vessel is fired or when rocks are heated) empties the stored energy, after which time the mineral begins absorbing energy again.
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.
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. We now report thermoluminescence (TL) dates that suggest the arrival of people between 50 and 60 kyr in northern Australia.TL dates were obtained from sandy footslope deposits at two former occupation sites that yielded a range of stone artefacts in their primary depositional setting.But when the rock is exposed to high enough levels of heat or light, that exposure causes vibrations in the mineral lattices and the trapped electrons are freed.The exposure to radioactive elements continues, and the minerals begin again storing free electrons in their structures.In the same way, more or less, OSL (optically stimulated luminescence) dating measures the last time an object was exposed to sunlight.