Fig. 5.

The δ¹⁵N of 90 bones of caballine horses of differing ages from Alaska’s North Slope. The numbered columns show the GIs. The green line shows the cumulative number of basal peat dates from Alaska (72). Red and yellow bars show the timing of the bone abundance peak in the early stages of GI-1. Horse diet changed radically as peat spread during GI-1. Similar shifts in diet occurred during some of the earlier interstadials. Bone ages are plotted by their median calibrated ages.