δ13C values of wood and Charcoal Reveal Broad Isotopic ranges at the base of the Food Web

Abstract

ABSTRACTThe aim of this study is to investigate the range, the degree of variability, and a possible time or species dependence of wood and charcoal δ13C values within one small study area. To achieve this, we used δ13C and 14C determinations of more than 400 archaeological samples from a ca. 300 ha area in Denmark, spanning 5000 years and covering several different species. The δ13C values of the wood and charcoal range from −32.8‰ to −21.2‰. We found no time-dependence of wood and charcoal δ13C values, neither in general nor within one species. The mean δ13C of all wood samples is −28.5‰, while the means of individual species range from −30.6‰ to −26.3‰. The mean of all charcoal samples is −25.7‰, with the means of individual species ranging from −28.1‰ to −24.3‰. The wood δ13C values can be used to infer the possible range of plant δ13C values, which otherwise are not available. They imply that a high degree of variability can be expected at the base of the food chain. This is relevant for palaeodietary studies that rely on the measurement of baseline isotope values.