Radiocarbon Dating of Ostrich Eggshells

Unlike wood charcoal, as found admixed to other cultural remains, ostrich eggshells can be of more direct significance in 14 C dating, especially if they were processed to form, eg, eggshell beads. Normally the time span between laying the egg and working the shell beads is short enough to be negligible for 14 C dating purposes. Another advantage of eggshell dating is that the carbonate of the shell seems to keep exceptionally well over the millennia, whereas, especially in surface sites in a desert environment, organic material such as wood, charcoal or bone protein tends to decompose. With few comparative test samples, we thought ostrich egg samples would yield 14 C dates somewhat too young. The deviation is, however, balanced by performing 13 C analyses and a correction for isotope fractionation of ca 350yr.