A continental-scale Eurasian ice sheet 2.4 million years ago

Understanding when ice sheets first developed over the continents is essential for attributing ice volume to marine records of global sea-level change. We resolve a long-standing terrestrial–marine mismatch in the timing of the first Eurasian Ice Sheet (EIS) expansion by dating the earliest glaciogenic unit in northwest Europe, the Hattem Bed Complex (HBC). Paired cosmogenic 26Al-10Be burial dating and detrital zircon fingerprinting indicate that glacially-derived Fennoscandian gravels reached the Netherlands 2.41\,-0.29+0.51 Ma, while ages from the overlying Appelscha Formation record a second EIS advance and attendant shutdown of the Baltic River System 1.72\,-0.25+0.25 Ma. Cyclic stratification of the HBC could reflect freshwater discharge to the North Atlantic associated with episodic disruption of meridional overturning circulation. The timing of the first trans-Baltic EIS overlaps the Laurentide Ice Sheet maximum (2.42\,-0.14+0.14\,Ma), underscoring substantial Northern Hemisphere ice growth more than a million years prior to the Mid-Pleistocene Transition. The earliest known glacial sediments in northwest Europe are dated using cosmogenic nuclides, revealing the first expansions of the Eurasian Ice Sheet at ~2.4 and ~1.7 million years ago.