Research Unit: Anthropology and Human Genetics, Department of Biology of Organisms and Ecology, Université Libre de Bruxelles, Brussels, Belgium.
UMR 5199: "PACEA-De la Préhistoire à l'Actuel: Culture, Environnement et Anthropologie", University of Bordeaux, Pessac Cedex, France.
PLoS One. 2021 Oct 13;16(10):e0257199. doi: 10.1371/journal.pone.0257199. eCollection 2021.
Cremation is a complex mortuary practice, involving a number of activities of the living towards the dead before, during, and after the destruction of the bodily soft tissues by fire. The limiting information concerning these behavioral patterns obtained from the pyre remains and/or cremation deposits prevents the reconstruction of the handling of the corpse during the burning process. This pioneering study tries to determine the initial positioning of the corpse in the pyre and assess whether the deceased was wearing closed leather shoes during cremation through isotopic (δ13C, δ18O) and infrared (ATR-FTIR) analyses of experimentally burnt pig remains, used as a proxy for humans. The results obtained show that both the position of feet on or within the pyre and the presence of footwears may moderately-to-highly influence the oxygen isotope ratios of bone apatite carbonates and the cyanamide content of calcined bone in certain situations. By forming a protective layer, shoes appear to temporarily delay the burning of the underlying pig tissues and to increase the heat-shielding effect of the soft tissues protecting the bone mineral fraction. In such case, bioapatite bone carbonates exchange oxygen with a relatively more 18O-depleted atmosphere (due to the influence of lignin-derived oxygen rather than cellulose-derived oxygen), resulting in more pronounced decrease in the δ18Ocarb values during burning of the shoed feet vs. unshoed feet. The shift observed here was as high as 2.5‰. A concomitant isotopic effect of the initial location of the feet in the pyres was also observed, resulting in a top-to-bottom decrease difference in the δ18Ocarb values of shoed feet of about 1.4‰ between each deposition level tested. Finally, the presence of cyanamide (CN/P ≥ 0.02) seems to be indicative of closed footwear since the latter creates favorable conditions for its incorporation into bone apatite.
火化是一项复杂的丧葬习俗，涉及到在人体软组织被火焚烧前后，生者对死者进行的一系列活动。从火葬柴堆遗骸和/或火化沉积物中获得的有关这些行为模式的有限信息，阻止了对在焚烧过程中对尸体进行处理的方式的重建。这项开创性的研究试图通过对用作人类替代品的实验燃烧猪遗骸进行同位素（δ13C、δ18O）和红外（ATR-FTIR）分析，确定尸体在火葬柴堆中的初始位置，并评估死者在火化时是否穿着封闭的皮鞋。研究结果表明，脚在柴堆上或柴堆内的位置以及是否穿鞋，在某些情况下可能会适度到高度地影响骨骼磷灰石碳酸盐的氧同位素比值和煅烧骨中的氰胺含量。鞋子通过形成保护层，似乎会暂时延缓下面猪组织的燃烧，并增加保护骨矿物质部分的软组织的隔热效果。在这种情况下，生物磷灰石骨骼碳酸盐与相对更贫 18O 的大气（由于木质素衍生氧而不是纤维素衍生氧的影响）进行氧交换，导致穿鞋的脚在燃烧过程中比不穿鞋的脚的 δ18Ocarb 值下降更为明显。这里观察到的变化高达 2.5‰。还观察到脚在柴堆中初始位置的伴随同位素效应，导致在每个测试的沉积水平之间，穿鞋的脚的 δ18Ocarb 值从上到下降低了约 1.4‰。最后，氰酰胺（CN/P≥0.02）的存在似乎表明穿着封闭的鞋子，因为后者为其掺入骨骼磷灰石创造了有利条件。
