Heat-induced Bone Diagenesis Probed by Vibrational Spectroscopy

Abstract

Complementary vibrational spectroscopic techniques – infrared, Raman and inelastic neutron scattering (INS) – were applied to the study of human bone burned under controlled conditions (400 to 1000 °C). This is an innovative way of tackling bone diagenesis upon burning, aiming at a quantitative evaluation of heat-induced dimensional changes allowing a reliable estimation of pre-burning skeletal dimensions. INS results allowed the concomitant observation of the hydroxyl libration (OHlibration), hydroxyl stretching (ν(OH)) and (OHlibration + ν(OH)) combination modes, leading to an unambiguous assignment of these INS features to bioapatite and confirming hydroxylation of bone’s inorganic matrix. The OHlib, ν(OH) and ν4(PO43−) bands were identified as spectral biomarkers, which displayed clear quantitative relationships with temperature revealing heat-induced changes in bone’s H-bonding pattern during the burning process. These results will enable the routine use of FTIR-ATR (Fourier Transform Infrared-Attenuated Total Reflectance) for the analysis of burned skeletal remains, which will be of the utmost significance in forensic, bioanthropological and archaeological contexts.

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).…”

Human bone probed by neutron diffraction: the burning process

“…This behavior was observed for all samples under study, in accordance with previous results obtained from INS and FTIR spectroscopy. 5,6,21,51 Fig . 2 represents the renements of the neutron diffraction data measured for tibia sections (T42) burned at high temperatures (800, 900 and 1000 C).…”

“…13,22,[34][35][36][37][38] Following several successful studies in burned human bone (400 to 1000 C) by combined FTIR, Raman and INS. [4][5][6]8,21,26 The present study aimed to complement these spectroscopic results with diffraction data leading to a more detailed interpretation of the chemical and microcrystallinity variations already revealed spectroscopically, that will identify skeletal remains subject to unknown heating conditions. Bone's chemical and crystallinity changes were probed, upon an aerobic burning process at different maximum temperatures (from 400 to 1000 C, chosen according to those reached in re and explosion settings).…”

“…variations in size), which interfere with the reliability of the available metric techniques that are based on references from unburned bones. [4][5][6][7][8][9] Heat-induced diagenetic variations in bone have been assessed by several methods, optical (Fourier transform infrared spectroscopy (FTIR) and Raman) and neutron vibrational spectroscopy (inelastic neutron scattering (INS)) having been established as powerful techniques for these types of study. [4][5][6][7][10][11][12][13][14][15][16][17][18][19][20] FTIR spectroscopy in attenuated total reectance mode (FTIR-ATR) is particularly suitable for a daily basis analysis of archaeological or forensic bones since it is easily accessible, inexpensive, fast and requires no specic sample preparation, yielding an accurate chemical and structural prole unique for each sample.…”

“…Hence, extensive work has been performed by FTIR-ATR on heat-prompted changes in human bone. [4][5][6]8,15,19,[21][22][23][24][25][26] These analyses rely on the calculation of spectroscopic indices, based on specic biomarker bands, that should deliver the chemical composition of the bone as well as its crystallinity details.…”