Reconstruction of postglacial palaeoenvironmental changes in eastern Lithuania: Evidence from lacustrine sediment data

Postglacial climatic conditions were inferred from the cores taken from two lakes in eastern Lithuania. Pollen, diatom, pigment, chemical analysis and 14C dating were performed. Vegetation with open herb/grass predominating flourished on the unstable soils, surrounding oligotrophic palaeobasins with high water levels and low pigment concentrations that existed at about 13,200 cal. The succeeding stage (13,200–12,600 cal BP) indicates a formation of pine–birch woodland, rising humidity as well as biogenic productivity, and points to climatic warming. At about 12,600 cal BP the re-establishment of open herb–grass–shrub communities was registered. Gradual improvement of climatic conditions started after 11,200 cal BP. The period from ∼8700 to ∼6000 cal BP shows an expansion of broad-leaved trees, significant increase in diatom diversity, diatom and pigment concentration, and drops in C/N ratio indicating the most favorable climatic conditions during the postglacial. After ∼4800 cal BP the broad-leaved trees markedly decreased and the significance of eutrophication and human activity increased.