post doctoral researcher
- Research database TUHAT
- The life and times of the woolly mammoth
- Life histories in teeth: new resources of isotope archaeology in Finland
- CARATE - tree-ring carbon isotopes tell stories of past climate evolution
- Levänluhta – Iron Age water burial site of 100 humans
As a part of the late Pleistocene megafaunal extinctions, the woolly mammoth (Mammuthus primigenius) disappeared from Eurasia ca. 12-10000 years ago. The species survived, however, for thousands of years after the mainland extinction on Wrangel Island, situated off the coast of Eastern Siberia. The last known occurrence of the woolly mammoth is radiocarbon dated to 4000 years ago. The life and times of the woolly mammoth are investigated in a collaboration between researchers at the Laboratory of Chronology, the Department of Geosciences and Geography at the University of Helsinki, and the University of Tübingen. The study material consists of subfossil bones and teeth (pictured below) of the woolly mammoth, which bear chemical signatures of their living conditions.
The isotopic composition of oxygen in the tooth enamel of mammoth teeth is linked to the climatic conditions via the drinking water of the animal, and describes the rainout patterns and ancient air temperatures of ice age Europe (Arppe & Karhu, 2010). The carbon isotope composition reflect regional differences in the diet and living environment of European mammoths (Arppe et al., 2011). The strontium isotope values of the Wrangel Island mammoths describe the movement patterns of the animals and record the isolation process of the island from the mainland (Arppe et al., 2009). According to current scientific literature the climate and vegetation of Wrangel Island did not chage significantly after the beginning of the Holocene period (ca. 10000 years ago), and studies of ancient-DNA reveal no loss of genetic diversity nearing the extinction. Thus the reason for their seemingly abrupt disappearance remains unresolved. In the ongoing collaborative investigation, the oxygen isotopic composition of the Wrangel Island mammoth teeth are used to draw a picture of climate, while carbon and nitrogen isotopes are analysed on collagen extracted from the skeletal materials to study the diet of the animals.
Arppe, L., Karhu, J.A., 2010. Oxygen isotope values of precipitation and the thermal climate in Europe during the middle to late Weichselian ice age. Quaternary Science Reviews 29, 1263–1275.
Arppe, L., Aaris-Sørensen, K., Daugnora, L., Lõugas, L., Wojtal, P., Zupins, I., 2011. The palaeoenvironmental d13C record in European woolly mammoth tooth enamel. Quaternary International 245, 285–290.
Arppe, L., Karhu, J. A. & Vartanyan, S. L., 2009. Bioapatite Sr-87/Sr-86 of the last woolly mammoths-Implications for the isolation of Wrangel Island. Geology 37, 347–350.
The isotopic compositions recorded in the teeth and bones of ancient humans and animals speak of their habits and habitats during life. Due to the acidic soils prevalent in Finland, finds of archaological skeletal material are rare. What usually remains, are teeth, which in the case of human finds are very small and extremely fragile. This poses a challenge to the study of these materials by isotopic techniques, as sampling of the material would destroy the entire find. Furthermore, making accurate interpretations of past subsistence strategies of ancient humans requires knowledge of the isotopi baseline, i.e. the isotopic values of the most commonly used food items such as fish, game and crops. This type of information is all but missing in Finland.
In a 3-year project funded by the Kone Foundation, we are developing new analytical techniques and data resources to promote isotope archaeological research in Finland. The project, led by Laura Arppe from Luomus, brings together scientists from the Universities of Turku, Helsinki, Tübingen and Fukushima. A large sampling of animals common in the diet of ancient humans will be analysed for stable isotopes from the collections of Luomus. The resulting data, along with all the available, published isotope records of animal collagen isotope values will be put in an open-access database. Moreover, new microsampling and analytical methods will be developed and implemented, to facilitate extraction of the full potential of stable isotope compositions of archaeological dental material. The newly developed resources will then be applied in the study of one of the most significant iron age contexts in Finland, the Eura Luistari cemetery.