The Early-Weichselian in northern central Europe – N-S and E-W transects of pollen records and their application for palaeoclimatic reconstructions
by
Holger Freund
Institute of Geobotany, University of Hannover, Germany

During the last decades several palynological investigations have been carried out on deposits of Weichselian age in northern central Europe. Above all comparison of Early Weichselian occurences and other representative sedimentary sequences from The Netherlands, Denmark, Poland and Belarus as well as from northwestern, midwestern and southern Germany shows up not only the differences in vegetational development and palaeoclimate but also migration paths and refuge areas of different trees. Here selected pollen records and maps of isopollen zones are presented for the Herning stadial (MIS 5d), the Brørup interstadial (MIS 5c), the Rederstall stadial (MIS 5b) and the Odderade interstadial (MIS 5a).

After the end of the Eemian interglacial (MIS 5e) in northern Europe, a decline in July average temperature to <10°C is signalled by the pollen, macrofossil and beetle evidence. This resulted in the demise of coniferous woodland that characterized the end of the Eemian. However, vegetation cover, in the form of heath-dominated and later grass-dominated tundra, remained complete and so soil erosion was hindered. For this, the usually thin deposits of the Herning do not necessarily indicate that this stadial was of short duration. The subsequent Brørup interstadial (MIS 5c) is characterized in northern central Europe by boreal coniferous woodland. Pollen analyses from several sites in Europe and the oxygen isotope record from deep sea cores provide evidence for a cooler period in the lower part of the Brørup interstadial (MIS 5c). This climatic deterioration, as a chronostratigraphical event, affected different forest ecosystems in different regions. On the basis of these studies the effects on the woodland composition could be demonstrated. Furthermore, the presence of species with present-day suboceanic distribution patterns indicate that the climate during the Brørup interstadial was less continental. The uplands of the German Mittelgebirge were probably the northern limit of thermophilous trees as e.g. oak and elm. A relatively short growing period as well as reduced precipatation are suggested as the main factors that limited the northerly and easterly extension of the warmth-demanding tree species. The palaeolimate up to the end of the Early Weichselian was characterized by an increasing continentality of climate. This is demonstrated by the comparison of isopollen maps (MIS 5d versus 5b, MIS 5c versus 5a) and the distribution pattern of some indicator taxa e.g. Artemisia. This climate development was mainly triggered by the lowering of sea-level, particularly in the North Sea area. Therefore any palaeoclimatic reconstruction must take the modified palaeogeography of northern central Europe into account.

Date received: March 12, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cagc-08.