Optical dating recuperation after bleaching

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.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.This phenomenon is associated with a resetting (“zeroing”) of the dosimetric clock; iii) after one or several transport phases the grain is “definitively” buried under a sedimentary cover.It is exposed again to radiation and accumulates trapped electrons.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.

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.Luminescence methods (TL and OSL) are based on the estimation of the impact of radiation on the crystalline structure of minerals while they are shielded from light (Aitken, 1985; Wintle, 1997; Aitken, 1998; Duller, 2004; Vandenberghe, 2004).The main minerals studied are quartz and K-rich feldspar, which can be found in almost all sedimentary environments.The radiation () comes from radionucleides which are present in the mineral and its natural environment, mainly uranium, thorium (and their decay products), potassium, and for a small proportion from cosmic particles (Aitken, 1985).They lead to the emission of electrons which are subsequently trapped in crystalline lattice defects.

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