Palaeoenvironmental and climate changes recorded in the lacustrine sediments of the Eemian Interglacial (MIS 5e) in the Radom Plain (Central Poland)

Abstract

The Radom Plain is a region with numerous fossil palaeolakes that formed a palaeolakeland. Lacustrine sediments of thickness varying from 0.5 to 18 m were encountered in numerous boreholes. Pollen analyses of the sediments filling the palaeolakes have proven that their sedimentation began after the retreat of the Saalian ice-sheet (MIS 6), continued during the Eemian Interglacial (MIS 5e), and terminated at the beginning of the Weichselian Glaciation (MIS 5d). Climate and palaeoenvironmental changes have been recorded in different deposits: muds, peats and gyttja. Local factors, such as reservoir depth, and geological conditions have influenced the type of the accumulated sediments. Eemian sites occur in two geomorphological positions: in small depressions on the glacial plateau and in small valleys in ox-bow palaeolakes. Eemian lakes were formed from the melting of dead-ice blocks. Pollen data obtained from the palaeolake sediments document climate and vegetation changes characteristic of the Late Glacial period, the Eemian Interglacial, and the beginning of the Weichselian Glaciation. In many sites, a record of a complete Eemian succession is present, whereas in others it is fragmentary. Comparison of pollen data between the Radom region and other localities in Poland shows local and regional differences in the development of forest communities in the Eemian. In the Eemian sequences of the Radom Plain, a considerable contribution of Tilia, Picea and Abies pollen is distinct in the forest communities, often higher than in other Eemian sites of Central Poland. The particularly high percentage of Tilia (exceeding 30%), Picea (up to 67%) and Abies (30%) pollen are recorded in the Babin site. This phenomenon may indicate favourable environmental and climate conditions, facilitating further propagation of these trees. In the pollen record from the Babin site, three distinct abrupt/cool climate oscillations have been noted, with the oldest one recorded in the Saalian Glaciation. The two younger oscillations have been distinguished at the very beginning and at the very end of the Last Interglacial, respectively. Eemian sites from the Radom Plain are important for the reconstruction of palaeoenvironmental and palaeoclimate changes in the Eemian Interglacial in Poland and Europe.