Viability of Raman microscopy to identify micro‐residues related to tool‐use and modern contaminants on prehistoric stone artefacts

Abstract

Analyses of ancient micro‐residues and usewear preserved on stone artefacts can potentially provide detailed information about how prehistoric humans used the artefacts to process materials such as food, pigments and/or adhesives. However, ancient micro‐residues are likely degraded, and there are multiple potential sources of contamination, such as contact with sediments, groundwater, recent handling, storage materials or laboratory conditions, any of which can inhibit reliable identification of micro‐residues and other traces of prehistoric use. In this pilot study, five stone tools from the archaeological site of Liang Bua (Flores, Indonesia) were used to evaluate the viability of Raman spectroscopy to identity ancient micro‐residues preserved on stone artefact surfaces that are due specifically to prehistoric use as opposed to some form of ancient or modern source of contamination. Inorganic and organic deposits that occur commonly in the cave environment, including iron oxide, manganese oxide and biofilms, were identified in both the sediment and on the artefacts. Protein and saturated fatty acid micro‐residues were identified on edges of all artefacts and may partially originate from modern handling. Proteins, plant fibres and other micro‐residues associated with calcium nitrate are possibly archaeologically significant. Detection of plant fibres and starch grains may indicate either modern contamination or prehistoric contact with plant material that was transferred incidentally or during tool manufacture and/or tool use. These results demonstrate the viability of Raman microscopy to screen, at an early stage of archaeological residue analysis, for modern contaminants and micro‐residues related to tool manufacture and/or tool use. This approach serves as a base for planning strategies and analytical protocols for future work that targets larger samples of artefacts, integrates Raman microscopy with GC–MS/LC–MS and includes more comprehensive studies of usewear. Copyright © 2017 John Wiley & Sons, Ltd.

Analysis of Pigments in the Buseoksa Josadang Murals in Yeongju

“…These characteristics are observed when the materials are fired. Comparison to the data obtained in the previous studies showed that the Raman spectroscopy confirmed that this spectrum was similar to that of the artificially produced [Ca 2 (PO 4 ) 2 ], bones containing collagen, and materials taken from burned animal bones(Figure 7)(Bordes et al, 2017;Marques et al, 2018;Jillavenkatesa and Condrate Sr, 1998).Natural white materials with Ca and P as the main elements, include fluorapatite[Ca 5 (PO 4 ) 3 F 2 ], which is a major component of teeth and bones. Fluorapatite mostly comes from Canada, Mexico, Brazil, Russia, Japan, and Myanmar, and is not produced in Korea(Doopedia, 2020).…”

Material processed with 58,000‐year‐old grindstones from Sibudu (KwaZulu‐Natal, South Africa) identified by means of Raman microspectroscopy

“…Moreover, a sharp band is observed at 1,052 cm −1 which can be attributed to calcium nitrate. As observed by Bordes and colleagues, the calcium nitrate could arise from a degradation process that occurred postdepositionally. It is not impossible that the bands at 1,003 and 1,052 cm −1 originated from burkeite.…”

Direct evidence of Neanderthal fibre technology and its cognitive and behavioral implications

“…Raman spectrometry was the most suitable technique considering is high spatial resolution and its non-invasive application. This technique is becoming increasingly common in analysis of residues on stone tools 21,22 and is used here to corroborate visual identification of plant residues.…”