Stable carbon isotopes in Grabie oak tree rings reveal Hallstatt climate changes in Poland

Abstract This study focuses on reconstructing paleoclimate changes between 830 BC and 650 BC, a period of critical significance marked by the Hallstatt Catastrophe, a shift from a warm and dry climate to a cool and humid one. This period also coincides with the onset of the plateau on the radiocarbon calibration curve. The research material consisted of oak tree trunks G24 and G58, discovered in Poland (Grabie village). Dendrochronological methods were employed to date the two trunks. The identification of the Miyake event around 660 BC in the Δ 14 C results from the Grabie tree rings corroborated the dendrochronological dating. This study presents an analysis of changes in stable carbon isotope composition in α-cellulose extracted from annual growth increments and variations in growth ring widths.