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The Ner River valley (central Poland) underwent substantial transformation during the Weichselian–Holocene transition as a result of fluvial processes and climate changes, resulting in the establishment of its present shape in the Holocene. A multiproxy study based on organic deposits from a palaeochannel fill (Lutomiersk–Koziówki) shows that after the channel was cut off during the late glacial termination, it became a shallow oxbow, fed by local springs. In the Boreal period, the oxbow lake was also fed by precipitation and became a telmatic environment overgrown by rush and swamp vegetation. Finally, it was covered by overbank deposits. The first flooding phase (9900–9600 cal. BP) was followed by the accumulation of overbank sediments (after 9500 cal. BP) and flooding increased after ca. 9300–9000 cal. BP. Pollen data provide information on the regional vegetation context for local and regional changes. In the Atlantic period, an increase in both summer and winter temperatures is inferred from the pollen data, corresponding to an expansion of thermophilous deciduous forests. While in general, flooding phases of the Early Holocene are poorly recognised in Eastern Europe, the Lutomiersk–Koziówki site may be considered as one of the reference points for this phenomenon in the region. [ABSTRACT FROM AUTHOR]

Abstract: The environmental conditions of the Szczecin Bay, which existed prior to Szczecin Lagoon, have been reconstructed on the basis of the stable carbon and oxygen isotope (18O and 13C) analysis and radiocarbon dates obtained for subfossil shells of Cerastoderma (Cardium) glaucum. The shells in the collected core were well preserved in their life positions, representing a geochemical record of past temperature variation over the middle Holocene. Three major periods with different thermal conditions have been distinguished in the interval ~6000–4300calyr BP, when the important Littorina regional transgression took place. During the first period, 6000–5250calyr BP, water temperature decreased by 1.4°C, and then remained constant over the second period (5250–4750calyr BP). In contrast, during the third period (4750–4300calyr BP) both δ-values were highly variable and the mean summer temperature (March–November) increased by about 3.5°C. During first two periods, δ18O and δ13C were significantly correlated, indicating stability of the environmental conditions. [Copyright &y& Elsevier]