What is Luminescence? Optically Stimulated Luminescence (OSL) Sediment Context Collection Procedures

Luminescence tutorial (next: Sediment Collection)

Optically Stimulated Luminescence Sediment Collection Procedure

Sedimentologic Context for Luminescence Dating

luminescence graphThere are a variety of sediments that have been and can be dated by luminescence. The selection and sampling of sediment is the first and crucial step in the luminescence analysis. A luminescence age is a measure of the time since the last sunlight exposure (or heating) event of the sediment. The reduction in luminescence, usually by sunlight, must be related to a significant environmental event (e.g. fault-generated colluvium, dune migration) for a luminescence age to be meaningful. The luminescence dating of sediment that was exposed to little or no light during a specific event will yield a spurious age.

The preferred sediment for OSL dating has had > 1 hr sunlight exposure, accumulated as relatively homogeneous stratigraphic unit, >30 cm thick and has not undergone significant water-content variations or diagenetic changes during burial. Selection of preferred sediment for a stratigraphic setting often requires a sedimentary facies analysis that considers efficiency of solar resetting of luminescence and bedding architecture with deposition. In many sedimentary environments, particularly eolian and littoral, coarse-grained (100-300 Ám) quartz grains is preferred for dating; it is an abundant particle size that is well solar reset. In other sedimentary settings the fine-grained (4-11 Ám) polymineral or quartz fraction is amenable for dating, particularly for loess, colluvial, eusturine, and many lacustrine and fluvial environments.

 

References and key luminescence dating publications