Stable isotope compositions of mammoth teeth from Niederweningen, Switzerland: Implications for the Late Pleistocene climate, environment, and diet

Oxygen and carbon isotope compositions of well-preserved mammoth teeth from the Middle Würmian (40–70 ka) peat layer of Niederweningen, the most important mammoth site in Switzerland, were analysed to reconstruct Late Pleistocene palaeoclimatic and palaeoenvironmental conditions. Drinking water δ18O values of approximately −12.3±0.9‰ were calculated from oxygen isotope compositions of mammoth tooth enamel apatite using a species-specific calibration for modern elephants. These δ18OH2Oδ18OH2O values reflect the mean oxygen isotope composition of the palaeo-precipitation and are similar to those directly measured for Late Pleistocene groundwater from aquifers in northern Switzerland and southern Germany. Using a present-day δ18OH2Oδ18OH2O-precipitation–air temperature relation for Switzerland, a mean annual air temperature (MAT) of around 4.3±2.1 °C can be calculated for the Middle Würmian at this site. This MAT is in good agreement with palaeotemperature estimates on the basis of Middle Würmian groundwater recharge temperatures and beetle assemblages. Hence, the climatic conditions in this region were around 4 °C cooler during the Middle Würmian interstadial phase, around 45–50 ka BP, than they are today.During this period the mammoths from Niederweningen lived in an open tundra-like, C3 plant-dominated environment as indicated by enamel δ13C values of −11.5±0.3‰ and pollen and macroplant fossils found in the embedding peat. The low variability of enamel δ13C and δ18O values from different mammoth teeth reflects similar environmental conditions and supports a relatively small time frame for the fossil assemblage.