OSL Dating
Luminescence Dating
OSL

Optically Stimulated Luminescence (OSL) Dating determines the time elapsed since mineral crystals were last exposed to sunlight, i.e. the time of sediment deposition. After the burial of sediment grains, natural environmental radiation gradually leads to the trapping of charges within mineral crystals. When the sample is exposed to light in a laboratory, these electrons are released and emit light; the intensity of this light indicates the accumulated radiation dose. The age is calculated by dividing the dose by the annual environmental radiation dose rate. Various types of sediments in various archaeological contexts can be dated using OSL; however, it is important that sediment grains have had adequate time during transport to be fully bleached by sunlight. If this is not the case, age can be overestimated. Typical applications of the method are environmental reconstruction, dating the abandonment or burial of archaeological objects, ditches or buildings, and determining sedimentation rates. Samples must be collected using light-tight tubes or cylinders, ideally by hammering these into the investigated profiles. Any sediment composed of sand and silt can be dated. The required sample size is 200-300 g for measuring the naturally absorbed dose using OSL, and an additional 500-1000 g of the surrounding sediment is needed to assess the environmental dose rate. Precision and accuracy depend on the completeness of natural bleaching during sediment transport and the amount of information about environmental conditions and the environmental dose rate. The relative error of the reported age is between 5-10%. The age range of the method is from a few decades to 40-50 thousand years when using quartz grains, but can be up to 300 thousand years when using feldspar grains for dating.

Optically stimulated luminescence (osl)

Analysis Method

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