T02_P08

Tree-ring-radiocarbon dating paraffin conserved charcoal: An experimental and archaeological case study

Kessler N¹

¹University Of Arizona, Tucson, United States

For wood and charcoal in museum collections, past conservation practices can be a challenge for high precision ¹⁴C-based chronometry. For example, in the United States, the treatment of archaeological charcoal with paraffin consolidant was a widespread practice. This complicates ¹⁴C dating of tree-ring segments in wiggle-matches as trace amounts of dead carbon can induce significant offsets. This poster presents experimental evidence for the efficacy of a solvent pretreatment protocol for known age and archaeological charcoal conserved with paraffin. FTIR and ¹⁴C analysis confirm that a chloroform pretreatment is very effective at removing paraffin from laboratory contaminated known-age charcoal as well as historically contaminated archaeological charcoal. Using the pretreatment protocol, new wiggle-matched dates were obtained from a large platform mound (Mound 10) at the Kincaid Site, a Mississippian center in southern Illinois U.S.A. Wiggle-matched cutting dates from the final construction episodes on Mound 10 at Kincaid, indicate that the mound was used in the late 1300s with the construction of a unique building on the apex occurring in the 1390s, just one or two generations prior to the depopulation of the site. This study demonstrates the potential for museum collections of archaeological charcoal to contribute high resolution chronological information through wiggle-matching despite past conservation practices that complicate ¹⁴C dating.