Estimation of temperatures beneath archaeological campfires using carbon stable isotope composition of soil organic matter

An Inceptisol and an Alfisol from Western Maryland were sampled by horizon and exposed to the elevated temperatures associated with heat transfer measured beneath campfires. Substantial loss in organic carbon and change in carbon stable isotope composition was observed, even after exposure to relatively low temperatures (200–400 °C). Analyses showed that a comparison of carbon isotope enrichment in organic matter beneath a suspected campfire site to that of unaltered soil would give quantitative information about the minimum effective campfire temperature. Application of these results may lead to particular insight for archaeological sites where soil surfaces have been eroded or otherwise truncated.