Revealing seasonal woolly mammoth migration with spatially-resolved trace element, Sr and O isotopic records of molar enamel

Abstract

We investigated the mobility pattern of an Upper Palaeolithic woolly mammoth (Mammuthus primigenius) from the Kraków Spadzista site in southern Poland, one of the largest mammoth bone accumulations in Europe. We conducted in situ laser ablation (MC-) ICPMS Sr isotopic and trace element concentration measurements accompanied by spatially-resolved oxygen isotope measurements of dental enamel on a last upper molar tooth (M6). Our study documents excellent preservation of in vivo geochemical and isotopic records and reveals recurring changes in 87Sr/86Sr that oscillate between two endmembers and correlate with analogous variations in δ18O, as well as U and Sr concentrations. The observed periodicity corresponds to annual cycles of enamel mineralization as revealed by enamel histology and documents up to 11 years of woolly mammoths' life in a single dental plate. The high degree of correlation between the duration of enamel mineralization and the Sr and O isotopic records suggests that the mammoth migrated between two areas of distinct Sr isotopic composition as well as characteristic U and Sr concentrations, presumably forced by seasonal food availability. The mammoth grazed in southern Poland in winter time as indicated by lower δ18O values and likely moved 250–400 km northwards to the Polish midlands during summer. This migration pattern remained stable for at least 12–13 years of the animal's adult life as archived in this molar tooth. Our study documents a fixed mobility behaviour of an adult mammoth some 10,000 years before the Last Glacial Maximum.