Vegetation and climate in the Early- and Pleni-Weichselian in northern Central Europe

Abstract

Analysis of numerous pollen diagrams from north and central Germany and from the adjacent lowlands of The Netherlands, Denmark, Poland and Belarus have facilitated a regional comparison of the vegetation and climatic evolution from the beginning of the Early Weichselian glaciation to the Weichselian pleniglacial. Data from geological studies and analysis of fossil beetles and plant macroremains have been used to supplement the palaeoclimatic reconstruction. Up to the end of the Oerel Interstadial the palaeoclimate was characterised by increasing continentality. The winter temperatures in particular tended to fall continuously during the stadials and the interstadials of the Early Weichselian and early Pleniglacial. In the Brorup and Odderade Interstadials summer temperatures where sufficiently high to enable boreal forests to grow, whereas in the Oerel Interstadial summer temperatures were such that tree growth was inhibited. It is probable that falling sea-level and the consequent extension northwards of the North Sea coast were the main causes of increasing continentality. In the latter part of the Pleniglacial, peat accumulation frequently took place and humic silts were deposited under lacustrine conditions. Correlation between various sites is extraordinarily difficult. Pollen diagrams from the so-called interstadials of the Glinde, Moershoofd Complex, Hengelo and Denekamp are similar to those of the known Early Weichselian stadials. It is proposed therefore that these interstadials should be called intervals, and that the term interstadial be reserved for climatic variations that result in distinctive pollen assemblages and which, in turn, reflect distinctive vegetation dynamics. Interstadials should be capable of being characterised on a biostratigraphical basis and it should be possible to establish correlations over considerable distances. According to this definition, the first three warm oscillations of the Weichselian glaciation in the central European lowlands are the Brorup, Odderade and Oerel Interstadials. All other pleniglacial peat layers should be assigned the rank of interval. Copyright © 2001 John Wiley & Sons, Ltd.