C04_P10

Using rapid atmospheric ¹⁴C changes to precise dating part of the floating chronology for pine tree from Józefowo (north Poland)

Wiktorowski D¹, Krąpiec M¹, Barniak J¹

¹AGH University of Science and Technology, Kraków, Poland

Miyake was the first to describe rapid and short-lasting increases of radiocarbon (¹⁴C) concentration in the annual tree rings between AD 774 and 775 and AD 993 and 994. This sudden increase of radiocarbon has been confirmed also by other scientists. Similar study has been conducted in Poland at the AGH University of Science and Technology. The results clearly show a rapid increase of ¹⁴C concentration in these years. Results of last studies confirmed that the abrupt increase in ¹⁴C concentration is also visible between 663 and 662 BC. In this period is also located the floating pine chronology for north Poland. Due to the characteristic of the sharp increase in radiocarbon concentration that occurs in this phenomena, and due to the global character of this effect, it is possible to use it for accurate dating of annual tree rings, using radiocarbon method. In practice, linking the relative dendrochronological dating and radiocarbon analysis of annual growth rings is possible to use “Wiggle matching” technique to precise determination of the calendar age. Samples from Grabie, a village near Krakow (south-easter Poland) were control series, of known calendar age and known changes of radiocarbon concentration around 660 BC. The values of these changes were compared with the values noted in samples of pine tree from Józefowo (floating pine chronology) to its precise dating (with an accuracy of up to one year). This allowed the absolute dating of tree rings from floating pine chronology, which has been so far unattainable using radiocarbon method.