Ostrich eggshell from archaeological sites remains largely free of more recent carbon contamination and as such is suitable material for radiocarbon dating. The carbonate fraction of the shell does, however, display an initial deficit in C14, which causes the ages to appear 180 ± 120 years too old.
Reference:
Vogel, JC, et al.2001. Suitability of Ostrich eggshell for radiocarbon dating. Radiocarbon, vol. 43(1), pp 133-137
Vogel, J., Visser, E., & Fuls, A. (2001). Suitability of Ostrich eggshell for radiocarbon dating. http://hdl.handle.net/10204/543
Vogel, JC, E Visser, and A Fuls "Suitability of Ostrich eggshell for radiocarbon dating." (2001) http://hdl.handle.net/10204/543
Vogel J, Visser E, Fuls A. Suitability of Ostrich eggshell for radiocarbon dating. 2001; http://hdl.handle.net/10204/543.
