Late Glacial stable isotope record, radiocarbon stratigraphy, pollen and mollusc analyses from the Geiseltal area, Central Germany

Combined investigations of isotopes, pollen, and mollusc shells were carried out on a Late Glacial limnic high-resolution sediment sequence from the Geiseltal open-cast mine in Central Germany. The data confirm the division of the Late Glacial biozones into two colder (Older and Younger Dryas) and two,warmer periods (Bolling, Allerod), which have already been established for the Central and Northern German area. Radiocarbon data, mainly based on wood material, cover a time span between c. 10800 BP and 12760 BP, indicating a mean sedimentation rate of c. 2 mm/yr. The stable isotope data (delta(18)O, delta(13)C) reflect the transition periods between the climatic phases as changes in relative air humidity (transition from dry, cold to warmer, more humid conditions). The dominance of evaporation effects, however, is superimposed on any temperature signal throughout the profile. Repeated conversions of the hydrologic regime (silting-up phases, lake-level variations) characterize the specific history of the lake development.