Search

To spatially characterize the palaeolakeshore environment at the archaeological kill site Schöningen 13 II‐4 of the Middle Pleistocene Reinsdorf sequence, in‐depth palynological, geochemical, aquatic microfossil and archaeological analyses were undertaken on sediment sections with an average thickness of about 15 cm, concordantly overlain by faunal remains, dominated by horse, from the unique 'Spear Horizon' layers of the 1995 excavation campaign. The data reveal a distinctive lake level drop, documented by the change from a carbonate‐rich lake marl to a carbonate‐free organic mud with increased carbon content and decreasing C/N, Si/Al, Si/K and Fe/Al ratios, indicating a higher pedogenic supply of organic matter and drier conditions at the site. Compared with older, similar transitional phases of lake level changes occurring within the Reinsdorf sequence, it is important that these youngest sediments are undisturbed, indicating continuous development. Ostracod and diatom analyses indicate a lowering water level with higher salinities and rich aquatic vegetation. Mesorheophilic ostracod species along with tychoplanktic diatom taxa point to flowing waters and turbulence at the lakeshore, presumably related to spring‐fed streams originating from nearby highlands. Palynological results reveal a very diverse zonal vegetation pattern around the palaeolakeshore considering an area of investigation of approximately 50 × 75 m and a tessellated type of regional vegetation during the formation of the archaeological horizons. On topographically lower elevated areas, birch groves and taxa favouring wet, marshy conditions such as Cyperaceae, indicative of terrestrialization, were predominating, while other stands of this transitional phase reveal a very dry, grass‐dominated steppe woodland favouring a rich wildlife with a striking number of megaherbivores. Our results suggest that the lithological differences of the 'Spear Horizon' layers containing the archaeological finds were due to their respective topographical situation and that the layers were deposited almost simultaneously during the beginning of the lake level drop. Human activities seem to have concentrated in sparsely vegetated areas along the palaeolakeshore, rather than in areas of adjacent denser birch swamp forest stands. [ABSTRACT FROM AUTHOR]

Lake‐level reconstructions are a key tool in hydro‐climate reconstructions, based on the assumption that lake‐level changes primarily reflect climatic changes. Although it is known that land cover changes can affect evapotranspiration and groundwater formation, this factor commonly receives little attention in the interpretation of past lake‐level changes. To address this issue in more detail, we explore the effects of land cover change on Holocene lake‐level fluctuations in Lake Tiefer See in the lowlands of northeastern Germany. We reconstruct lake‐level changes based on the analysis of 28 sediment records from different water depths and from the shore. We compare the results with land cover changes inferred from pollen data. We also apply hydrological modelling to quantify effects of land cover change on evapotranspiration and the lake level. Our reconstruction shows an overall lake‐level amplitude of about 10 m during the Holocene, with the highest fluctuations during the Early and Late Holocene. Only smaller fluctuations during the Middle Holocene can unambiguously be attributed to climatic fluctuations because the land cover was stable during that period. Fluctuations during the Early and Late Holocene are at least partly related to changes in natural and anthropogenic land cover. For several intervals the reconstructed lake‐level changes agree well with variations in modelled groundwater recharge inferred from land cover changes. In general, the observed amplitudes of lake‐level fluctuations are larger than expected from climatic changes alone and thus underline that land cover changes in lake catchments must be considered in climatic interpretations of past lake‐level fluctuations. [ABSTRACT FROM AUTHOR]