Optically Stimulated Luminescence Dating of Sediments

Optically stimulated luminescence (OSL) dating exploits the ability of quartz and feldspar minerals within sediment to store energy from environmental radiation. When mineral grains are exposed to daylight prior to burial, trapped charge is emptied; subsequent shielding by burial allows charge to accumulate in crystal defects. In the laboratory, controlled optical stimulation releases the stored energy as luminescence, the intensity of which is proportional to the accumulated radiation dose. By determining the equivalent dose (the total absorbed dose since last exposure) and dividing by the environmental dose rate, the time elapsed since burial can be calculated. OSL dating spans timescales from decades to several hundred thousand years and finds applications in reconstructing fluvial and aeolian sedimentation, tracing glacial dynamics, establishing archaeological chronologies and informing palaeoclimatic models. Recent methodological developments—such as single-grain analysis, post-infrared infrared stimulated luminescence (pIRIR) and improved statistical age models—have enhanced precision and addressed challenges of incomplete bleaching, signal saturation and dose-rate heterogeneity. This geochronological tool thus underpins a broad range of Earth-system and archaeological research, offering a robust chronometer for sedimentary archives worldwide.

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Optically Stimulated Luminescence Dating of Sediments publication trend

The graph below shows the total number of articles in optically stimulated luminescence dating of sediments across all publications each year (not limited to Nature Index journals).

Technical terms

Optically stimulated luminescence (OSL): Emission of light from mineral grains when stimulated by light, used to determine the time since burial.

Equivalent dose (De): Total radiation dose absorbed by a sample since its last zeroing event (typically daylight exposure).

Dose rate: Rate at which environmental radiation is absorbed by sediment, expressed in grays per thousand years.

Partial bleaching: Incomplete resetting of the luminescence signal prior to burial, leading to mixed equivalent-dose distributions.

Signal saturation: Limitation in dose response at high radiation doses, reducing accuracy for older deposits.

Single-aliquot regenerative-dose (SAR) protocol: Laboratory procedure to determine equivalent dose by repeated cycles of radiation and optical stimulation on a single sample aliquot.

Beta-dose heterogeneity: Spatial variability of beta radiation within sediment, affecting dose‐rate calculations and equivalent-dose scatter.

References

1. On the importance of grain size in luminescence dating using quartz. Radiation Measurements (2017).
2. Empirical assessment of beta dose heterogeneity in sediments: Implications for luminescence dating. Quaternary Geochronology (2020).
3. Seeking enlightenment of fluvial sediment pathways by optically stimulated luminescence signal bleaching of river sediments and deltaic deposits. Earth Surface Dynamics (2019).