High-precision dendro-14C dating of two cedar wood sequences from First Intermediate Period and Middle Kingdom Egypt and a small regional climate-related 14C divergence

Abstract

Cedar (Cedrus sp.) wood from two archaeological contexts in Egypt – (i) the First Intermediate Period coffin of Ipi-ha-ishutef, (ii) a funerary boat at the pyramid of Middle Kingdom king Senusret (or Sesostris or Senwosret) III – form floating tree-ring sequences. Since one of the sample sets had been mounted with Elmer's glue products in core-mounts for dendrochronological examination, we investigate whether pretreatment can remove this potential contaminant before 14C dating. We find that even in (unrealistic) cases of extensive glue contamination this can be largely/successfully removed – making it likely that the samples in this study, where, moreover, only wood samples without traces of glue were employed, can provide accurate 14C dates. Dendro-14C-wiggle-matching was then employed to provide precise calendar dates for the two tree-ring sequences. The last extant ring of the Ipi-ha-ishutef coffin lies ca. 2081–2064 BC (95.4% probability), supporting, but refining, its assumed date. In the case of the Senusret III boat, we find a temporary, small, but important offset within the period ca. 2200–1900 BC in contemporary 14C ages between the Levant and central and northern Europe. It is suggested this is likely a result of exaggeration of normal seasonal variations in the uptake of 14C and its latitudinal distribution caused by climate change in the 2200–1900 BC/4200–3900 Cal BP (y2k) interval. A date for the last extant ring of the Senusret III boat is probably around 1898/95–1879/76 BC (95.4% probability) – more consistent with a high Middle Kingdom Egyptian chronology.