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

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 C-14 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 C-14 dates. Dendro-C-14-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 C-14 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 C-14 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. (C) 2014 Elsevier Ltd. All rights reserved.