Implications for the Late Pleistocene climate in Finland and adjacent areas from the isotopic composition of mammoth skeletal remains

Nine samples of subfossil bone and teeth remains from woolly mammoth (Mammuthus primigenius) discovered in Finland, Russian Karelia and Western Russia were analyzed for the oxygen isotope composition of the phosphate fraction and the carbon and oxygen isotope composition of the carbonate fraction in skeletal apatite. The samples have been radiocarbon dated in previous studies and are of late Middle Weichselian to Late Weichselian age. The preservation of the samples was tested analyzing the chemical composition and checking the isotopic equilibrium between the phosphate and carbonate components in skeletal apatite. According to these tests, five out of the nine samples were determined to have retained their original isotopic composition. These samples were used to estimate Late Pleistocene climatic conditions in Finland and neighboring areas. Based on the best-preserved enamel samples, the isotopic composition of oxygen in Late Pleistocene precipitation was 1–3‰ lower than that in the mean annual precipitation in southern and central Finland today. Using the relationship between the isotopic composition of precipitation and the ambient temperature, it can be estimated that the mean temperatures during the Middle Weichselian ice-free period were 2–6 °C lower compared to the present-day values.