Establishing a preservation index for bone, dentin, and enamel bioapatite mineral using ATR-FTIR
•ATR-FTIR ratios from well- and poorly-preserved bioapatite are compared.•Minimal differences are observed in ratios from deer and humans.•Raw and chemically processed sample ratios differ and require separate application.•Raw sample IRSF and processed sample C/P most accurately identify poor preser...
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| Published in: | Journal of archaeological science, reports Vol. 33; p. 102551 |
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| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Elsevier Ltd
01-10-2020
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | •ATR-FTIR ratios from well- and poorly-preserved bioapatite are compared.•Minimal differences are observed in ratios from deer and humans.•Raw and chemically processed sample ratios differ and require separate application.•Raw sample IRSF and processed sample C/P most accurately identify poor preservation.•A tissue-specific preservation index is established to identify altered bioapatite.
Chemical and structural analysis of archaeological bioapatite requires well-preserved unaltered mineral. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) is rapidly becoming a valuable technique to pre-screen bioapatite alteration as it is relatively fast and minimally destructive (<1 mg powdered material). We present robust ATR-FTIR data of modern and archaeological bone, dentin, and enamel to establish a tissue-specific preservation index. Specifically, this study adds (1) dentin and enamel data that is currently lacking in the literature; (2) examines differences between modern, well-preserved archaeological, and poorly-preserved archaeological materials; (3) examines inter-species differences; (4) compares raw and chemically processed samples; and (5) establishes an index of ATR-FTIR peak height ratios (C/P, IRSF, C/C, BPI, API) beyond which bioapatite is likely altered. Results show minimal differences between deer and human remains, suggesting that either species can be used as a quick pre-screen of general site quality assuming minimal difference in intra-site diagenetic factors. Raw and processed samples must be considered separately as removal of secondary carbonates and organics changes the crystallinity. The C/P ratio emerged as the most distinctive between well- and poorly-preserved samples after processing. If analysis of raw samples is preferred to conserve sample material, time, and resources, the IRSF of raw samples is the best value to eliminate poorly-preserved bioapatite. However, using the IRSF of raw samples will also eliminate some well-preserved bioapatite from further consideration. Finally, we combine our results with previously reported literature values to provide a distinct range of ATR-FTIR ratio values, which we term a preservation index, to distinguish between well- and poorly-preserved archaeological samples. |
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| ISSN: | 2352-409X |
| DOI: | 10.1016/j.jasrep.2020.102551 |