Re‐investigation of the Bispingen palaeolake sediment succession (northern Germany) reveals that the Last Interglacial (Eemian) in northern‐central Europe lasted at least ~15 000 years

Abstract

Investigating past interglacial climatic and environmental changes can enhance our understanding of the natural rates and ranges of climate variability under interglacial boundary conditions. However, comparing past interglacial palaeoclimate records from different regions and archives is often complicated by differing and uncertain chronologies. For instance, the duration of the Last Interglacial in Europe is still controversial as southern European palaeoclimate records suggest a duration of ~16 500–18 000 years, while a length of only ~11 000 years in northern‐central Europe was previously inferred from the analysis of partly annually laminated (varved) palaeolake sediments recovered at Bispingen, northern Germany. To resolve this discrepancy, we here present sediment microfacies, geochemistry and pollen data from a new sediment core from the Bispingen palaeolake sediment succession, covering the entire Last Interglacial (Eemian) and the earliest part of the Last Glacial (Weichselian). In particular, we provide evidence that the duration of the Last Interglacial at Bispingen must have been hitherto underestimated due to the investigation of an incomplete sediment core. Using microscopic varve counting and sedimentation rate estimates for non‐varved sections on the new sediment core, we show that the Eemian in northern‐central Europe probably lasted at least ~15 000 years, about 4000 years longer than previously thought. This new duration estimate is in much better agreement with results from southern European palaeoclimate records, clarifying the enigma of a steep trans‐European vegetation gradient for several millennia at the end of the Last Interglacial.

Stratigraphy and OSL chronology of the Middle–Upper Pleistocene sedimentary sequence and vegetation history during Late MIS6–MIS5e in the Neva Lowland (St. Petersburg region, Russia)

“…According to our Bayesian model, the Mikulino Interglacial lasted from 133 ± 8 to 109 ± 7 ka. These age bounds (within measurement uncertainties) do not contradict the 11-15 ka Eemian duration determined before from varve chronology (Müller, 1974;Lauterbach et al, 2024) and are also consistent with the correlation between the Mikulino Interglacial and MIS5e at 130-115 ka (Shackleton et al, 2002;Lisiecki and Raymo, 2005).…”

“…Later, varve chronology investigations were conducted for two other Eemian sections in Northern Germany, Quakenbrück (Hahne et al, 1994) and Gross Todtshorn (Caspers, 1997), which provided similar durations for several pollen zones. The Bispingen section was recently reinvestigated, and it was inferred (Lauterbach et al, 2024) that the Eemian lacustrine deposits accumulated there for at least ~15 ka, which is about 4 ka longer than previously thought. However, the reliability of the Bispingen chronology is limited owing to the absence of varves in the second half of the Eemian.…”

“…We built the natural DRC for our samples (Figure 12B) and calculated expected doses with reference to expected ages. We assumed an age of the Baltic deposits of ∼13 ka (Gromig et al, 2019), and the expected ages of samples from the Mga deposits were based on the chronology of the Eemian pollen zones (Lambeck et al, 2006;Lauterbach et al, 2024). For the Leningrad sediments, the quartz OSL ages were used as expected ages since they are consistent with the 14 C ages from other Leningrad sections in the Neva Lowland and adjacent areas (Malakhovsky et al, 1969b;Arslanov et al, 1981;Krasnov et al, 1995).…”