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Ostrich eggshell bead 87Sr/86Sr versus the highland baseline. (A) 87Sr/86Sr values of individual ostrich eggshell bead specimens from Melikane and Sehonghong arranged according to broad chronological phase and shown against the highland baseline (purple line = mean; purple bands = 2σ). Note that the sample’s third most 87Sr/86Sr-enriched bead (SEH I13-170) is also its oldest (∼33 ka). (B) The same data presented as boxplots.
