Optical dating of sediments
Feldspars have the specificity of being sensitive both to short and to near-infrared or infrared wavelength (800-950 nm; Bøtter-Jensen ., 1994); iv) the sensitivity of the trap to light.
Released electrons can recombine with another kind of crystalline defects (“holes” reflecting electrons vacancies).
Hence it underlines the increasing importance of the method to geomorphological research, especially by contributing to the development of quantitative geomorphology.
L’objectif de cet article est de proposer une présentation d’ensemble des méthodes de datations par luminescence stimulée optiquement (OSL) et de leurs applications dans le champ des recherches en géomorphologie.
They are now largely used to date not only palaeontological or organic remains, but also minerals that characterise detrital clastic sedimentary material.
The most common methods applied to minerals are cosmogenic radionuclides, electron spin resonance (ESR) and luminescence techniques.
The rate of release depends on four main parameters: i) the kind of mineral: the eviction occurs faster for quartz than for feldspars (reduction of the luminescence signal by a factor of 100 in ~ 20 s for the former, but a few minutes for the latter; Godfrey-Smith , these are more efficient to stimulate and release the electrons.The general principles of the method are described first.The paper then explains how OSL dating is applied to obtain a depositional age, through the field and laboratory procedures employed.These procedures are described as clearly as possible in order to provide useful information for geomorphologists interested in the method, and illustrated by a case study that has involved luminescence dating of fluvial sands (samples LUM 975 and LUM 978) from the lower alluvial terrace of the Moselle River (M1 terrace as defined by S. However, it is essential to keep in mind that the protocols (preparation of the sediments, measurements) may vary from one laboratory to the other: the presentation does not aim to be exhaustive, but to reference the main procedures at each step of the dating.Finally the paper reviews the recent applications of OSL dating in France, and assesses the potential of applying the luminescence dating technique to a range of geomorphic research.