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EN
During the construction of the S-3 road near Gorzów Wielkopolski, a sedimentary succession of the Eemian Interglacial and the older part of the Weichselian Glaciation were exposed. The succession, ~22 m thick, consists of lacustrine and fluvioglacial deposits. Lake sediments, mainly calcareous gyttja with peat intercalations, represent the infills of two palaeolakes. The almost complete skeleton of a forest rhinoceros, Stephanorhinus kirchbergensis, and a bone of the fallow deer Dama dama were found in the older lake deposits. Mollusc shells were numerous in both lake sequences, analysis of which revealed two types of assemblage, representing the coastal, littoral zone of a shallow lake with a muddy bottom. The sequence of mollusc communities observed in vertical succession allowed reconstruction of environmental changes during deposition. Several hydrological changes have been recognized within the palaeolake, especially water level fluctuations probably due to climate change.
EN
New optically stimulated luminescence (OSL) ages show that sandy deposits overlain by Late Weichselian subglacial till in central Latvia are of Early to Middle Weichselian age. The finer chronological resolution of unconsolidated sediment deposition in the Central Latvian Lowland (CLL) remains relatively unstudied, and here we provide a first characterisation of the deposits with respect to their age. Three OSL ages ranging between 84 ± 9 ka and 112 ± 11 ka suggest that the deposits studied in the CLL are of Early Weichselian age (MIS 5). We found no Middle Weichselian deposits in the CLL, and assume that any such younger sediments might have been eroded during the advance of the Zemgale Lobe in the Late Weichselian. One site, in the ice-marginal zone adjacent to the interlobate area, has nevertheless deposits dated to 44 ± 10 ka corresponding to the Middle Weichselian (MIS 3). Our results are compatible with existing ESR ages on three sets of Portlandia arctica shells from the central part of the lowland; the shells had been incorporated into glacial deposits during later glacial advances. Finally, our findings largely support ice-free conditions during the Early and Middle Weichselian in the middle and southern part of central Latvia.
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