Fig. 3.

Greenland and circum-Arctic sources of ice-rafted debris from 48–26 Ma delivered to Site 913 in the Greenland Sea and the ACEX site in the central Arctic Ocean. Vertical blue lines indicate intervals with significant numbers of grains matched to a source at Site 913. a At Site 913, the number of grains matched to sources on Greenland (red line) and to Arctic sources (blue line). Vertical blue bars mark intervals with samples containing IRD. b Published ACEX data³⁷ reported using ages calculated using one published age model⁶⁹ (green line) that indicate an Arctic sea ice history corroborated by our results, after factoring in differences in resolution and errors in age models for both sites. Purple line shows the same data but with sample ages calculated using a second age model⁶⁸. The Supplementary Information discusses the published ACEX age models in more detail. The Eocene-–Oligocene boundary is ~34 Ma