Two million years of the Eurasian Ice Sheet

Reconstructions of Northern Hemisphere ice sheets throughout the Quaternary are central to interpreting past variations in sea level, ocean-atmospheric circulation, and climate. Yet, terrestrial records of the earliest glaciations are fragmentary and anchored principally to relative chronostratigraphic frameworks, limiting direct comparison with more continuous marine archives. Here, we present new dating and sedimentary provenance constraints, motivating reassessment of the early history of the Eurasian Ice Sheet (EIS) and its role within the evolving Pleistocene climate system.

Cosmogenic ²⁶Al-¹⁰Be burial dating of key glacigenic deposits from northwest and central Europe reveals that extensive EIS advances occurred repeatedly during the Early Pleistocene, beginning as early as ~2.35 million years ago (Ma), and substantially predating the traditionally inferred onset of lowland glaciation during marine isotope stages (MIS) 16–12 (~0.65–0.45 Ma). Detrital zircon U-Pb fingerprinting of these deposits indicates that successive EIS advances transported sediment from the Fennoscandian Shield into the North Sea Basin and the North European Plain, implying that ice flow pathways through the Baltic Depression were established already in the Early Pleistocene and the Baltic (Eridanos) River System had terminated by at least ~1.5 Ma.

Our revised chronologies highlight that the most extensive EIS configurations formed prior to the Middle Pleistocene Transition, and within the context of apparent low-amplitude glacial cycles of the ‘41-kyr world.’ When integrated with independent geochronologic evidence from North America, these findings (within uncertainties) point to broadly synchronous Early–Middle Pleistocene expansions of the major Northern Hemisphere ice sheets. Such early attainment of continental-scale ice sheets may help to reconcile available terrestrial evidence with emerging reconstructions of significant glacial sea-level lowstands prior to the dominance of ~100-thousand year glacial cycles.

More generally, this synthesis calls for re-examination of long-standing European Quaternary stratigraphic frameworks and suggests that Eurasian glaciation may have played an important role in reorganizing continental drainage, modulating freshwater delivery to the North Atlantic, and influencing ocean-atmospheric circulation throughout the Early–Middle Pleistocene.