RADIOCARBON CONCENTRATION IN SUB-ANNUAL TREE RINGS FROM POLAND AROUND 660 BCE

The article presents results of measurements of radiocarbon (14C) concentration in sub-annual dendrochronologically dated tree rings of English oak (Quercus robur L.) from Grabie village near Krakow (southern Poland). Samples of early wood (EW) and late wood (LW) spanning the years 664-658 BCE. & alpha;-cellulose was extracted from each sample and their radiocarbon content was measured at the ATOMKI laboratory in Debrecen, Hungary. The EW and LW data confirm a prolonged increase in & UDelta;14C values around 665-663 as was observed by Park et al. (2017), Rakowski et al. (2019), or Sakurai et al. (2020). In addition, we found that this event may consist of two relatively small events, as was proposed by Sakurai et al. (2020). Based on obtained in this and previous study data we estimate that the occurrence of the two events were between 665 and 664 BCE (Rakowski et al. 2019), and in late spring of 663 BCE (May-June, before beginning of LW formation).

Automated summary

The article presents the results of measuring radiocarbon concentration in English oak tree rings in southern Poland and confirms a prolonged increase in radiocarbon values during a specific time period. The study also suggests that this event may consist of two smaller events.