Revisiting the potential of carbonized grain to preserve biogenic 87 Sr/86 Sr signatures within the burial environment

Strontium (Sr) isotope analysis of archaeological crops is a potential method of provenancing and identifying the movement of crops in the past, but there remains uncertainty about whether original 87Sr/86Sr values can be obtained from carbonized buried grains. We have determined that hydrochloric acid (HCl) leaching removes some, but not all, exogenous Sr from carbonized cereal grains buried in soil for up to one year. We conclude that while further work could refine the leaching method, Sr isotope analysis of archaeological cereal grains can distinguish crops sourced from outside a particular (e.g., local) area if it can be shown that leaching moves grain 87Sr/86Sr values significantly away from the expected Sr signature

The preservation and interpretation of δ34 S values in charred archaeobotanical remains

The measurement of sulphur isotope (δ34S) values in charred plant remains has the potential to inform understanding of the spatial configuration and ecology of crop production. We investigated the effects of charring, manuring, oxidation and anaerobic soil conditions on modern cereal grain/pulse seed δ34S values, and assessed the effect of chemical pre‐treatment on charred modern and archaeobotanical grain/seed δ34S values. We used these results to interpret δ34S values in archaeobotanical material from Neolithic Çatalhöyük. Our results suggest that δ34S values can be reliably preserved in charred grain/seeds but are subject to influence by anaerobic soil conditions, the effect depending on the timing of flooding in relation to S assimilation