Optical dating wiki
This is usually, but not always, the case with Aeolian deposits, such as sand dunes and loess, and some water-laid deposits.
All sediments and soils contain trace amounts of radioactive isotopes including uranium, thorium, rubidium and potassium.
During the 1960s and 70s, the Oxford University Research Laboratory for Archaeology and History of Art led in the development of TL as a method of dating archaeological materials.
Optical dating is a method of determining how long ago minerals were last exposed to daylight.
The exposure to radioactive elements continues, and the minerals begin again storing free electrons in their structures.
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.
Better still, unlike radiocarbon dating, the effect luminescence dating measures increases with time.
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.
Ages can be determined typically from 300 to 100,000 years BP, and can be reliable when suitable methods are used and proper checks are done.
Ages can be obtained outside this range, but they should be regarded with caution.