Synchronizing ¹⁰Be in two varved lake sediment records to IntCal13 ¹⁴C during three grand solar minima

Abstract. Timescale uncertainties between paleoclimate reconstructions often inhibit studying the exact timing, spatial expression and driving mechanisms of climate variations. Detecting and aligning the globally common cosmogenic radionuclide production signal via a curve fitting method provides a tool for the quasi-continuous synchronization of paleoclimate archives. In this study, we apply this approach to synchronize ¹⁰Be records from varved sediments of Tiefer See and Lake Czechowskie covering the Maunder, Homeric and 5500 a BP grand solar minima with ¹⁴C production rates inferred from the IntCal13 calibration curve. Our analyses indicate best fits with ¹⁴C production rates when the ¹⁰Be records from Tiefer See were shifted for 8 (−12∕ + 4) (Maunder Minimum), 31 (−16∕ + 12) (Homeric Minimum) and 86 (−22∕ + 18) years (5500 a BP grand solar minimum) towards the past. The best fit between the Lake Czechowskie ¹⁰Be record for the 5500 a BP grand solar minimum and ¹⁴C production was obtained when the ¹⁰Be time series was shifted 29 (−8∕ + 7) years towards present. No significant fits were detected between the Lake Czechowskie ¹⁰Be records for the Maunder and Homeric minima and ¹⁴C production, likely due to intensified in-lake sediment resuspension since about 2800 a BP, transporting old ¹⁰Be to the coring location. Our results provide a proof of concept for facilitating ¹⁰Be in varved lake sediments as a novel synchronization tool required for investigating leads and lags of proxy responses to climate variability. However, they also point to some limitations of ¹⁰Be in these archives, mainly connected to in-lake sediment resuspension processes.