Etude géochimique des sédiments endokarstiques par microsonde XRF : apports à la connaissance de ces dépôts originaux.

The aim is to show the interest of endokarstic detritic sediments studied as an environmental record. The techniques of high resolution study available today, particularly geochemical analyses by XRF microscanner (“X-Ray Fluorescence”), allow us to better determine the potentialities of these original continental recorders. From the analysis of various underground sediments (Vercors, Pyrenees...), we present geochemical specificities of these different deposits. The question of the variability of the signatures according to sites is also tackled. Lastly, the implications of these studies for palaeoenvironmental reconstructions are discussed; in particular, they present serious assets for local studies. By this comparative approach, we wish to highlight the potential of information which conceal the underground detritic sediments, on various temporal scales (Holocene to Actual), with an infra-annual precision (varved deposits), and integrating at the same time environmental evolutions and impacts of human activities on the environment.