What is optically stimulated luminescence dating
This instrument stimulates the luminescence signal of the sand through shining the sample with blue or infrared light-emitting-didoes (LEDs), which give the electrons enough energy to escape their traps and recombine elsewhere, emitting a photon of light.
The gamma spectrometer has been put into the sample hole (see the lead going from the gamma spectrometer crystal to the control box). Optically stimulated luminescence is a method of determining the age of burial of quartz or feldspar bearing sediments based upon principles of radiation and excitation within crystal lattices, and stems from the fact that imperfections in a crystal lattice have the ability to store ionizing energy (Radiation is absorbed by the crystal lattice upon sediment burial, and over time, excites electrons causing them to migrate within the crystal and become stored in traps resulting from crystal lattice defects.This page was contributed by Dr Georgina King from the Aberystwyth Luminescence Research Laboratory in the Institute for Geography and Earth Sciences. OSL is used on glacial landforms that contain sand, such as sandur or sediments in glacial streams. If the OSL signal is not fully reset, it may result in an age overestimation. OSL specialists overcome these challenges through only sampling certain glacial landforms, where greater sunlight exposure is likely to have occurred prior to deposition e.g. Quartz luminescence dating of Anglian Stage (MIS 12) fluvial sediments: Comparison of SAR age estimates to the terrace chronology of the Middle Thames valley, UK.
We analyse the quartz or feldspar minerals in sand deposits.