T02_P27

Preliminary study to reduce the amount of sampling

for ¹⁴C dating of non-buried ivory

Wojcieszak M¹, Ligovich G, Van den Brande T, Boudin M

¹Royal Institute for Cultural Heritage (KIK/IRPA), Brussels, Belgium

According to European law and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), worked ivory and raw tusks acquired before 1947 can be traded in the EU. Radiocarbon dating is an effective method to recognise ivory formed after 1947 since during 1950s and 1960s atomic bomb testing created a large increase in atmospheric radiocarbon content. Prior to dating the ivory, the common pre-treatment method is the same as the one used for bone and consists of extracting the collagen. Depending on the age and state of the ivory sample, the collagen content varies between ~10 and 20 % by weight. To obtain enough collagen for dating, around 100 mg of sample is needed and around 3.5 mg of collagen is combusted and graphitised. In this study we compared the ¹⁴C dates of samples prepared with the traditional collagen extraction, and samples directly combusted without any treatment. The preliminary tests show almost no differences between the dates obtained with the two methods. Around 10 mg of sample were used for the direct combustion method, which reduces the amount of sample needed by 10 times. This would be significant in the case of small ivory objects. However, this procedure can only be performed with non-buried materials since a pre-treatment is necessary in the case of buried ones.