Modern contaminants affecting microscopic residue analysis on stone tools: A word of caution.
Residue analysis is a method frequently used to infer the function of stone tools and it is very often applied in combination with use-wear analysis. Beyond its undeniable potential, the method itself has several intrinsic constraints. Apart from the exceptional circumstances necessary for residues to survive, the correct identification of the residue type is a very debatable topic. Before attempting to recognise ancient residues, a proper method should allow analysts to identify possible modern contaminants and exclude them from the final interpretation. Therefore, analysts should not underestimate the presence of modern contaminants and might learn how to discriminate the background noise due to handling. The main aim of this research is to provide some methodological improvements to residue analysis through the characterisation of some modern residues often present on the surface of stone tools (e.g. skin flakes, modelling clay). This characterisation was done by using both optical light microscopy (OLM) and scanning electron microscopy (SEM). Finally, a special care in the post-excavation treatment of stone tools is claimed in order to avoid major contamination of the samples.
IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Zona Educacional 4, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain; Àrea de Prehistòria, Universitat Rovira i Virgili, Fac. de Lletres, Av. Catalunya 35, 43002 Tarragona, Spain; Histoire Naturelle de l'Homme Préhistorique (HNHP, UMR 7194), Sorbonne Universités, Muséum national d'Histoire naturelle, CNRS, Université Perpignan Via Dominica, 1 rue René Panhard, 75013 Paris, France. Electronic address: antonella.pedergnana@gmail.com.
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Pedergnana
IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Zona Educacional 4, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain; Àrea de Prehistòria, Universitat Rovira i Virgili, Fac. de Lletres, Av. Catalunya 35, 43002 Tarragona, Spain.
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Asryan
SERP, Seminari d'Estudis i Recerques Prehistòriques. Dept. Prehistòria, H. Antiga i Arqueologia, Facultat de Geografia i Història, Universitat de Barcelona, c/Montalegre 6-8, 08001 Barcelona, Spain; IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Zona Educacional 4, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain.
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Fernández-Marchena
IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Zona Educacional 4, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain; Àrea de Prehistòria, Universitat Rovira i Virgili, Fac. de Lletres, Av. Catalunya 35, 43002 Tarragona, Spain.
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Ollé
Micro-residue analysis; Optical light microscopy; Sample contamination; Scanning electron microscopy