ESR dating of quartz extracted from Quaternary sediments application to fluvial terraces system of northern France [ Datation par résonance paramagnétique électronique (RPE) de quartz fluviatiles quaternaires: application aux systèmes de terrasses du nord de la France.]

Abstract

Since the 1980's, the improvement of the Electron Spin Resonance (ESR) method and its application to the dating of bleached quartz extracted from sediments currently allow to provide geochronological data on Pleistocene fluvial deposits and associated archaeological sites. The ESR dating of quartz may hence improve our knowledge on Quaternary chronostratigraphy, especially in case of azoic deposits, when classical methods can't be applied. The ESR method is based on the behaviour of aluminium-center in quartz exposed to solar light and ionizing radiations. This center can be optically bleached during the fluvial transport but, as this bleaching is incomplete, a residual dose must be determined and used for the age calculation. After a short description of the general principle of the ESR dating, the methodological basis and analytical procedures corresponding to the quartz are detailed, then the potential of the ESR method is demonstrated through the presentation of the results obtained from the study of the fluvial terraces of the Creuse and Yonne valleys (France).