Determination of eroded geological formations using organic matter characterization (Moulin basin, Alpes-de-Haute-Provence, France).

The present study is based on the optical (palynofacies) and geochemical (p yrolyse Rock-Eval) characterization of the organic matter occurring both in bedrock, soils, river sediments (suspended matter and bedload) in a Draix Erosional Research Basin (Cemagref). Results confirm firstly the contributi on of reworked organic matter in modern fluxes. Numerous previous studies h ave shown that organic matter analysis can be an accurate tool to provide i nformation concerning past climates and past environments. Present results suggests that such analysis can also give information concerning the charac terization of eroded bedrocks and of erosional. processes such as river ban k erosion and runoff. (C) 2000 Acadimie des sciences/Editions scientifiques et medicales Elsevier SAS.