Integrating Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and Multidetector Computed Tomography for Analysis of Heat-Induced Changes in Bone

Abstract

Charred and burned human and animal skeletal remains are frequently found in archaeological records and can also be subjects of forensic investigations. Heat exposure causes specific changes to the physical and chemical characteristics of these remains, offering valuable insights into their taphonomic history. This research combines the commonly used ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared) spectroscopy with the rarely utilised density measurements obtained from Multidetector CT (Computed Tomography) to investigate changes in defleshed bovine cortical bone exposed to different temperatures for varying durations. The inclusion of density measurements is significant because Multidetector CT analysis is non-destructive and can be valuable when remains cannot be removed from their burial context (e.g., urn) or cannot be damaged. The results indicate complex changes in both organic and inorganic components, affecting crystallinity and density. Lower temperatures primarily affect organic matter, while higher temperatures induce significant changes in the mineral lattice and phase transitions. The transformation from β-tricalcium phosphate to α-tricalcium phosphate at high temperatures likely impacts the bone's crystallinity and density. Bone density measured by CT scans provided additional information that complemented the interpretations of FTIR spectroscopy. While CT scans offer important data for planning non-destructive analyses of remains, they present only one layer of information. Therefore, CT scans need to be combined with other techniques to provide comprehensive interpretations of the changes occurring in the bone. Further research is needed on density measurements and other potentially non-destructive analyses to fully unlock the potential of Multidetector CT analyses.

Keywords: ATR-FTIR spectroscopy; FTIR indices; Multidetector CT; cremation; density; skeletal remains.

Figure 1

Confidence intervals of FTIR indices for different temperatures and durations of exposure.

Figure 2

CT density for different temperatures and durations of exposure.