EVALUATION OF FE ISOTOPE VALUES AS A PROVENANCE TOOL FOR CHERT ARTEFACTS FROM THE NORTH-EASTERN UNITED STATES* R. MATHUR† and J. BURNS Geology Department, Juniata College, Huntingdon, PA 16652, USA W. POWELL Department of Earth and Environmental Sciences, CUNY, Brooklyn, NY 11210, USA R. BORYK Geology Department, Juniata College, Huntingdon, PA 16652, USA B. SHEETZ Department of Earth and Environmental Sciences, CUNY, Brooklyn, NY 11210, USA and Geosciences Department, State College, Pennsylvania State University, PA, USA P. D’AMICOP. HARNEY Geology Department, Juniata College, Huntingdon, PA 16652, USA Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were com- pared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in central Pennsylvania, United States, where both veined chert (Bald Eagle chert) and stone tools coexist within several metres. Yellow ar- tefacts (δ 56 Fe = 0.38 ± 0.1, n = 7) and source materials (δ 56 Fe = 0.42 ± 0.1, n = 8) isotopically matched within error. The source values also overlap yellow chert samples from three other Bald Eagle chert locations in the area. These values are different from six other chert locations in the north-eastern United States. These data suggest that the Fe isotope composition of chert artefacts reflect distinct geological sources. To enhance the mechanical characteristics of the stone tools, the chert experienced heat treatment, which induced a phase shift of the Fe oxide mineral goethite to hematite. This phase shift changes the colour of the chert to red. The red chert artefacts and source material also have overlapping Fe isotope values, but are 0.2‰ higher than the initial yellow chert. Experimental work where cherts were heated with different clays shows that Fe exchange with site soils induces the +0.2 fractionation. These data dem- onstrate that predictable Fe isotope fractionation occurs during heating, resulting in isotopi- cally distinct artefacts. KEYWORDS: IRON ISOTOPE, CHERT GEOCHEMISTRY, STONE TOOLS INTRODUCTION Cherts are siliceous, crystalline to cryptocrystalline rock formations that were used throughout prehistory by human hunter-gatherers, foragers and farmers because they can be worked to *Received 21 October 2019; accepted 20 April 2020 †Corresponding author: email mathurr@juniata.edu Archaeometry 62, Suppl. 1 (2020) 156–168 doi: 10.1111/arcm.12572 © 2020 University of Oxford