Lithic residue analysis at Star Carr

Ancient trace residues left on stone artefacts by people represent a source of potentially fruitful data about diet, technology, and behaviour, but their investigation is not problem-free. Rather, correct identification of degraded residues and determination of their natural or anthropogenic origin remains at the heart of current methodological development in lithic residue analysis. This thesis addresses these issues by examining: 1) 13 modern reference residues on flint flakes, 2) modern residues on 78 experimentally buried flint flakes at Star Carr and off-site, and 3) residue traces on 138 archaeological stone artefacts from Star Carr. The study of modern reference residues showed that only residue types bearing diagnostic structures can be confidently identified by visual analysis alone. The study of experimentally buried flakes showed that tree resin, softwood tissue, and red ochre preserved after both one month and 11 months burial periods and across three burial environments, and were the most likely candidates to be encountered archaeologically. When the archaeological material was examined using reflected visible light microscopy (VLM), hypotheses of residue origin based on visual observations were tested against chemical information collected from the residues. Importantly, the microscopic hypotheses of residue identity based on comparison with reference residues and published literature were, in nearly all cases, falsified by confocal Raman microspectroscopy (micro-Raman) and gas chromatography-mass spectrometry (GC-MS). Key identifications were: iron (III) oxide, gypsum, quartz, pyrite, and organics. Some residue samples also contained compounds consistent with pine tree resin, but this finding is considered preliminary. These results from stone artefacts highlight the need in lithic residue analysis for: 1) more careful consideration of chemical processes in the burial environment, and 2) further incorporation of appropriate scientific techniques to verify microscopic residue identifications.