YOUNGER DRYAS AND EARLY HOLOCENE LAKE-LEVEL FLUCTUATIONS IN THE JURA MOUNTAINS, FRANCE

Lake-level fluctuations in the Jura mountains (France) during the Youn ger Dryas and the early Holocene are reconstructed using sedimentologi cal analyses. Major transgressive phases culminated just before the La acher See tephra deposition, at the beginning of the Younger Dryas, be tween 9000 and 8000 BP and between 7000 and 6000 BP. The Younger Dryas appears to be characterized by increasing dryness. Other major loweri ng phases occurred during the middle Allerod and during the Preboreal. A transgressive event developed between c. 9700 and 9500 BP. These pa laeohydrological changes can be related to climatic oscillations recon structed from pollen and isotopic records in Swiss lakes, from glacier movements and timberline variations in the Alps, and from isotopic re cords in the Greenland ice sheet.