Optical dating of young tidal sediments in the Danish Wadden Sea

We have tested the applicability of optically stimulated luminescence (OSL) to the dating of young estuarine sediments (<1000 years) to determine whether this method can be used to complement and support existing techniques, such as ²¹⁰Pb dating. The degree of bleaching before deposition is investigated by examining the age trend in various sediment cores, and where possible, by comparison with independent age control provided by ²¹⁰Pb dating. The consistency between optical ages and ²¹⁰Pb ages is shown to be satisfactory on a time-scale down to only a few years.

We conclude that OSL provides reliable and reproducible results in cores from sub-, inter- and supra-tidal sediments, ranging from only a few years up to 1000 years old, confirming its value in the estimation of estuarine accretion rates. With OSL it is, for the first time, possible to date sediment cores from silty and sandy tidal flats, providing a new approach to the problem of evaluation of stability and calculation of sediment budgets for estuaries and coastal lagoons.