Optical dating of sediments
Some of the traps are considered ‘unstable’ (“shallow traps”), which means that an electron inside will not remain trapped for the whole duration of burial.
On the contrary, defects situated deeper inside the lattice have a higher thermal lifetime.
Much later the grain is sampled in the field and stimulated in the laboratory using either visible light for quartz (OSL As shown in fig.
2, the luminescence signal obtained by stimulation corresponds with a decay curve which shows the progressive emptying of the electrons from the traps.
An outline of the general physical principles of luminescence dating is given.
A case study of fluvial sands from the lower terrace of the Moselle valley is then presented to describe the range of field and laboratory procedures required for successful luminescence dating.
The paper also reviews the place of OSL dating in geomorphological research in France and assesses its potential for further research, by focusing on the diversity of sedimentary environments and topics to which it can be usefully applied.
The latter were first applied to burned minerals from archaeological artefacts [thermoluminescence (TL) method].
Improvements of this technique led to the development, for more than twenty years, of the optical dating method [commonly referred to as Optically Stimuled Luminescence (OSL)] which is now applied to sediments from various origins (Wintle, 2008).