Dating quaternary events by luminescence
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.
Luminescence dating refers to a group of methods of determining how long ago mineral grains were last exposed to sunlight or sufficient heating.
Better still, unlike radiocarbon dating, the effect luminescence dating measures increases with time.
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.
At a number of sites in Chile it has been possible to confirm the validity of these OSL ages by comparison with cosmogenic radionuclide measurements on boulders associated with moraines.
Together, the OSL and cosmogenic ages have enabled a detailed record of glacier fluctuations in this key area through the Holocene.