Analogous trends in pollen percentages and carbon stable isotope composition of Holocene peat - Possible interpretation for palaeoclimate studies

Pollen and spore analysis and analysis of carbon stable isotope composition in a peat core from Hala Izerska (SW Poland) were used for palaeoclimate studies of the Holocene over the last ~ 8.5 ka. The results of these two methods have been compared and variations of the δ13C value show a clear relationship with the pollen percentages of tree taxa, such as Carpinus, Fagus, Picea, and Pinus as well as with spores of Sphagnum and akinetes of Cyanophyta. However, lags of up to ~ 200 years of pollen maxima and minima versus δ13C were observed. The δ13C value in the peat core varied between − 23.47 and − 27.58‰ and is interpreted here as reflecting temperature control of the carbon isotope composition of the peat. According to this interpretation and pollen analysis of the study area, the following climatic periods for the Holocene can be described: Atlantic–beginning warm (8.50–7.90 ka cal. BP) followed by moderated cold (7.90–5.75 ka cal. BP), Subboreal–beginning moderated cold (5.75–5.40 ka cal. BP) then warm (5.40–2.55 ka cal. BP), Subatlantic–beginning warm (2.55–2.20 ka cal. BP) then cold and moderate cold (2.20 ka–0.40 ka cal. BP) with a climatic minimum ~ 1.60 ka cal. BP. The highest relative difference between growing season temperatures was about 3.6 °C, which has been observed between the Subboreal temperature maximum (5.00 ka cal. BP) and the Subatlantic temperature minimum (1.60 ka cal. BP).