Chronology attempt since 2300 years of sandy deposits, pedogenised, in Fontainebleau forest (France).

The issue of successive Quaternary sandy deposits and of their pedogenesis, observed in the forests of the Paris basin, is elucidated by a site to the west of Fontainebleau forest which allows us to establish a chronology. Th e superposition of three sandy, complete, soils at the site of 'Beorlots' h as revealed the presence of wood coals in the Al horizon of a deep leached soil. The age of 330 BC for the C-14 dating implies that the leaching of th ese sands, deposited during the Late-Glacial period had finished at that ti me. This pedogenesis was replaced by a podzolisation of acid sands (two upp er soils deposited, one between 330 BC and 1000 AD, the other between 1330 BC and the present day). The interpretation of the kind of sand deposit, fo r the two upper soils, is uncertain at this site, but the hypothesis of imp ortant blowings in the west of the forest is proposed for other sites equal ly distant from sandstone table-lands, uncovered in the past. The palynolog y reveals the permanence of pine trees in the forest during the Subatlantic period, a very open cover from 330 BC until the end of 18th century, and a n afforestation with pine during the 19th century. (C) 2000 Academie des sc iences / Editions scientifiques et medicales Elsevier SAS.