Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: www.elsevier.com/locate/jas Raman spectroscopy of lipid micro-residues on Middle Palaeolithic stone tools from Denisova Cave, Siberia Luc Bordes a , Richard Fullagar a , Linda C. Prinsloo a , Elspeth Hayes a , Maxim B. Kozlikin b,c , Michael V. Shunkov b,d , Anatoly P. Derevianko b,c , Richard G. Roberts a,e,* a Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia b Institute of Archaeology and Ethnography, Russian Academy of Sciences, Siberian Branch, Novosibirsk, RU-630090, Russia c Altai State University, Barnaul, RU-656049, Russia d Novosibirsk National Research State University, Novosibirsk, RU-630090, Russia e Australian Research Council (ARC) Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales 2522, Australia ARTICLE INFO Keywords: Fatty acids Stone artefacts Usewear Microwear Tool function Animal skin processing ABSTRACT Raman spectroscopy is a powerful method for detecting micro-residues on stone tools. To further develop techniques for determining stone tool function, we devised a methodology using Raman microscopy to analyse in situ micro-residues before conventional usewear study. We analysed 18 stone artefacts collected in situ from Denisova Cave in Siberia, where excellent organic residue preservation is expected. We report here details of saturated and unsaturated fatty acids identified on eight stone tools from the Middle Palaeolithic levels. The spatial distribution of smeared fatty acids shows strong correlation with spatial distributions of usewear (par- ticularly use-polish, but also striations, edge rounding and scarring) on each tool, demonstrating that these micro-residues are likely associated with prehistoric tool contact with animal tissue. We compared Raman spectra and the types, abundance and distribution of micro-residues on the Denisova Cave artefacts with those on modern experimental stone tools (with known function). The results provide further support for Middle Palaeolithic processing of animal tissue and probable skin scraping at Denisova Cave. 1. Introduction As underscored by previous analysts, the visual characterisation of micro-residues using optical microscopes is challenging when the residues lack distinct shapes or structures (Langejans, 2012; Monnier et al., 2012, 2017a,b; Wadley and Lombard, 2007). In these conditions, micro-residues resulting from stone tool use also pose challenges because they are more difficult to distinguish from modern contaminants, mineral background or from the effects of post-depositional processes (Langejans, 2010). Spectroscopic analyses have been applied previously to characterise visible traces of glue and adhesive compounds, after macroscopic or low- magnification observations (e.g., Cârciumaru et al., 2012; Vahur et al., 2011). Similarly, microscopic usewear studies have been complemented by subsequent application of spectroscopic techniques (e.g., infrared and Raman spectroscopy) to residues potentially linked with utilised tool edges (e.g., Cesaro and Lemorini, 2012; Hogberg et al., 2009). Other studies have applied Raman or infrared spectroscopy at a later stage of functional analysis, to confirm origins of organic residues that were previously identified as distinct structures by optical microscopy (Monnier et al., 2013, 2017a; b). To confirm that micro-residues are related to prehistoric tool use and not the outcome of another agency (such as contamination from handling or sediments), it is important to assess multiple lines of evidence (e.g., Lombard and Wadley, 2009), including micro-residue abundance and meaningful distributions (Rots et al., 2016). For example, micro-residues that are distributed widely on artefact surfaces may potentially be a consequence of contact with sediment (or various taphonomic processes) rather than tool use, which typically constrains impacted residues close to used tool edges. Previous studies have shown that it is usually appropriate to record and document residues before undertaking detailed usewear analysis, which often requires cleaning of tools to observe wear on tool surfaces (Keeley, 1980). In situ, non-destructive study of residues should be undertaken before residues are removed for chemical and other testing. A common first step in study of tool residues is optical microscopy to identify tools and residues that may then be subjected to further testing. In this study, prehistoric stone tools were not first selected on the basis of optical microscopy or any macro-residues. Our study aimed to evaluate Raman microscopy (Raman spectroscopy with optical https://doi.org/10.1016/j.jas.2018.05.001 Received 31 January 2018; Received in revised form 1 May 2018; Accepted 3 May 2018 * Corresponding author. Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia. E-mail address: rgrob@uow.edu.au (R.G. Roberts). Journal of Archaeological Science 95 (2018) 52–63 Available online 26 May 2018 0305-4403/ © 2018 Elsevier Ltd. All rights reserved. T