Post-glacial environmental history in NE Poland based on sedimentary records from the Dobrzyń Lakeland

Abstract

This paper presents a comprehensive palaeoenvironmental data set from a trough between glacial curvilineations (an intra-GCL trough) of the Dobrzyń Lake District, north-central Poland. A sediment core taken from the depression was investigated to reconstruct Late Glacial and Holocene environmental changes in north-central Poland using a combination of palynological, macrofossil, sedimentological and geochemical studies. Four main development phases of the studied intra-GCL trough were distinguished. Accumulation of the analysed sediments occurred from the Late Vistulian (Glacial Phase) through the Late Glacial to present times. Our data suggest the persistence of dead ice in the basin up to the Older Dryas (Lacustrine Phase). The sedimentary record of the depression reflects a considerable difference between the Late Glacial/early Holocene and the middle/late Holocene in terms of environmental conditions. The Late Glacial was characterised by rapid environmental changes, while climatic conditions throughout the Holocene were relatively stable, except for the Subboreal period. A small lake was strictly dependent on climatically controlled vegetation changes and erosion tendencies in the vicinity of the Zbójenko site. The lake finally disappeared at the turn of the Younger Dryas and the Preboreal Period. The Preboreal, Boreal and Atlantic Periods encompassed the Early Paludical Phase, during which the water level used to rise and hence the mire could be flooded. The area was covered with dense vegetation and the rate of denudation processes around the site was moderate. The Late Paludical Phase included the Subboreal and most of the Subatlantic. Deciduous forests (with Quercus, Carpinus, Corylus) dominated around the site. Major changes occurred between the late Subboreal and the early Subatlanic as a result of the growing human impact on the environment. The Subatlantic ends with the human impact phase (Middle Age), dominated by human impact, little accumulation of sediments and highly increased denudation.