20-EPN2-118: Solar activity studies around 660 BC and 800 BC by radiocarbon analysis of annual tree rings using accelerator mass spectrometry
Visit by Ivan Kontul, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava (Slovakia), to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 29 August – 09 September 2022
Report Summary: Several relatively rapid spikes in radiocarbon levels have recently been found by radiocarbon analysis of tree rings, most notably the 774-775 AD increase. Additional measurements confirmed this C-14 spike to be a global event and the evaluation of radiocarbon data showed that these excursions could be connected to rapid changes in solar activity. Similar changes in radiocarbon levels have been observed in tree-ring samples from USA and Germany around 660 BC and tree rings from USA around 800 BC. The measurement of annual growth rings from other parts of the world could contribute to the research of rapid changes in past radiocarbon levels and their connection to solar activity.
During this Europlanet visit, we used accelerator mass spectrometry to measure radiocarbon content of dendrochronologically dated tree rings from Yamal peninsula in Siberia covering the periods 836-779 BC and 671-651 BC. The measurements of tree rings from these periods show that the 660 BC and 800 BC excursions are present in tree-ring record from a different part of the world as previous measurements (Germany, Poland and Japan for 660 BC; USA and Japan for 800 BC), and it indicates the events causing these spikes have indeed a global character.