Estimation of the pre-burning condition of human remains in forensic contexts

PhD Thesis, 2012

The analysis of burned bone stumbles on the problems raised by the heatinduced changes that seriously interfere with the methods adopted by biological anthropologists. These changes especially affect the structure of bone leading to fragmentation, dimensional modification, warping and fracturing. As a result, quantitative analysis based on measurements and weighing are usually overlooked due to uncertainties regarding their ability to correctly process burned skeletal remains. Although some pioneering research on this issue has been carried out in the Past, this remained sporadic and with little application from bioanthropologists. In addition, a significant part of that research was either developed on rather small samples of human bones or on samples of faunal bones. Also, some other investigation was carried out by extrapolating from the results obtained on unburned skeletons, which is an inadequate indirect approach. The present research tackled these problems by analysing present-day cremations on a modern crematorium in order to investigate three distinct issues. The first one regarded the relevance of heat-induced warping and thumbnail fracturing for the determination of the pre-cremation condition of the human remains. Secondly, the implication of heat-related dimensional change on sexual dimorphism and consequent sex determination from calcined bones was addressed. Finally, the value of postcremation skeletal weights for bioarchaeological interpretation of funerary contexts was also investigated. This was done by examining human skeletons both prior and after cremation on two different cremation samples: one composed of recently dead cadavers submitted to cremation; and another one composed of dry skeletons recently exhumed. The research demonstrated that, although heat-induced warping and thumbnail fracturing is much more typical of cremations on fleshed cadavers, these features are also present on the burned remains of defleshed skeletons. Therefore, the occurrence of these features is probably related to the preservation of collagen-apatite bonds which play an important role on the mechanical strength of bone. As for sexual dimorphism, the results revealed that it is not significantly affected by heat and that such differences between females and males can be useful to classify unknown individuals according to sex based on the univariate metric analysis of calcined bones. Therefore, sex determination of this kind of material needs not to rely exclusively on the examination of morphological traits which requires a multivariate approach. At last, logistic regression coefficients that are able to estimate the expected proportion of the specific skeletal regions present on funerary assemblages were developed. This was carried out in order to assist on the interpretation of the course of action adopted during the recovery of the skeletal remains from the pyre and their consequent deposition in the grave. Such method was proven to be more dependable than previous ones based on weight references from unburned skeletons. This research demonstrated that, although heat-induced bone changes can indeed be very extensive, their analytical potential is not completely wiped out. Nonetheless, such analysis needs to be based on references that are specific to burned bone to allow for reliable insights. As a result, additional research is needed to better equip bioanthropologists with new analytical techniques more suitable for the investigation of burned human skeletal remains.

2021

This document is the fourth in a series of guides aimed at promoting best practice in different aspects of archaeological science, produced by members of the Science and Technology in Archaeology and Culture Research Center (STARC) of The Cyprus Institute. The current document was largely developed in the context of two projects: People in Motion and Promised. The implementation of People in Motion involved the laboratory study of a large commingled and partially burned skeletal assemblage from Byzantine Amathus, Cyprus, which came to light in the context of excavations led by the Cypriot Department of Antiquities. Osteological work on this assemblage was co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research and Innovation Foundation (EXCELLENCE/1216/0023). In addition, Promised aims at promoting archaeological sciences in the Eastern Mediterranean, with funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 811068. The study of burned skeletal remains is particularly challenging due to the extensive alteration of the bones, manifesting as warping, discoloration, shrinkage, and fracturing. These macroscopic changes express underlying structural and chemical alterations. As a result, the application of traditional osteological methods (morphological, metric, chemical, molecular, histological and others) is largely inhibited or should be extremely cautious. Nonetheless, the study of burned skeletal assemblages can offer unique insights to funerary practices and technologies, as well as the manipulation of dead bodies. In line with the above, the aim of this guide is to cover various aspects of the study of burned skeletal assemblages. It should be seen as a supplement to the ‘Basic guidelines for the excavation and study of human skeletal remains; STARC Guide no. 1 ’ and the ‘Excavation and study of commingled human skeletal remains; STARC Guide no. 2’. The current guide is meant to serve only as a general outline and the described field and lab-based methods should be modified depending on the context and characteristics of each assemblage under study. A number of excellent volumes have been published in the past years, compiling experimental and case studies on the retrieval and examination of burned skeletal remains in archaeological and forensic contexts (Fairgrieve 2008; Schmidt and Symes 2015; Symes et al. 2012; Thompson 2015). Much of the information presented here has been drawn from these resources, as well as from other publications and the author’s professional experience. References are given throughout the current document but the aim is by no means to provide an exhaustive account of the literature. This document is an open resource and it is anticipated to be updated at regular intervals. I would greatly appreciate any feedback and recommendations for future improvement.

Burn trauma is prevalent in both archaeological and forensic records. It causes thermogenic modifications that have implications for the discipline of anthropology. Anthropologists and medical professionals are frequently the experts called to address burn trauma cases, often in the role of forensic anthropologists. This project seeks to discuss the processes of burn trauma and the resulting changes, as well as how the professionals in the fields of archaeology, anthropology, and medicine are discussing the recovery and analysis of burned human remains. An experiment is used to demonstrate these changes and compare them to those documented by experts in the field. A literature review discusses the processes of burn trauma and the resulting thermogenic modifications that are seen in the scholarly literature on the topic. The author makes recommendations for future research, namely the inclusion of weight in the recorded factors during experimentation and continued research into the recovery of burned remains. The author argues that the bioarchaeological approach of forensic anthropology benefits from the combined experience of archaeologists, biological anthropologists, and medical experts who have a background in osteology and biomechanics.

2024

The excavation of burnt human remains derived particularly from collective burials in a commingled state of deposition requires expertise and meticulous documentation. A multidisciplinary perspective enhances our perception of the depositional history as well as the formation mechanisms of skeletal assemblages. A careful examination of the human bones contributes to the decoding of the dynamic environmental, social, and cultural processes that are related to the archaeological context. The analysis of burnt bone assemblages combined with detailed documentation of the archaeological context is a challenging procedure. This paper aims to provide a comprehensive overview of the current state of the art in studying burnt bones, with a particular focus on the evaluation of biological and archaeological interpretations. The study of macroscopic thermal changes has advanced considerably in recent years based on the results of experimental, medical, and forensic studies applied to both human and animal remains. Meticulous recording of the thermal alterations in the bone through the integrated investigation of discoloration, fracture patterns, warping, and shrinkage offers reliable conclusions about burial behavior in terms of burning and treating the dead in past societies, including evidence about the burning event(s) and the post-depositional activities that affected the human remains.

Journal of Archaeological Method and Theory, 2020

The practice of cremation is often interpreted as an alternative to inhumation, taking place shortly after an individual's death. However, cremation could be a final stage in complex mortuary practices, with previous steps that are obscured due to the heating process. This project reports on experimental scoping research on a set of experimentally heated femoral fragments from modern and archaeological collections of the University of Coimbra. Sixteen recent femur samples from eight individuals, as well as five femur samples from an archaeological skeleton from the medieval-modern cemetery found at the Hospital de Santo António (Porto), were included in this research. Samples presented five different conditions: unburnt, and burnt at maximum temperatures of 300°C, 500°C, 700°C and 900°C. Each sample was prepared to allow observation using binocular transmitted light microscopes with ×10, ×25 and ×40 magnifications. Results indicated that, if burial led to bioerosion, this will remain visible despite burning, as could be in cases where cremation was used as a funerary practice following inhumation. From this, we conclude that the observation of bioerosion lesions in histological thin sections of cremated bone can be used to interpret potential pre-cremation treatment of the body, with application possibilities for both archaeological and forensic contexts. However, the effect on bioerosion of substances such as bacterial-or enzymatic-based products often used to accelerate decomposition should be investigated.

Cadernos do GEEvH 1(1), 2012

The interdisciplinary research of burned bones is focused in this paper by presenting and discussing some methods that can assist the bioanthropologist in the analysis of this kind of remains. In particular, some techniques based on the histological structure of bone and on its molecular composition allow new ways of identifying burned human bone and of determining some aspects of the biological and ontological profile of an individual. A brief summary of those techniques is thus here presented.

Legal medicine (Tokyo, Japan), 2017

The colour of thermally altered bone, recovered from archaeological and forensic contexts, is related to the temperature(s) to which it was exposed. As it is heated bone changes in colour from ivory white, to brown and black, to different shades of grey and chalky white. It should be possible to estimate exposure temperature based on visually observable changes in colour. In forensic casework the temperature that human remains have been subjected to can reveal information about the existence and nature of foul play. Therefore, it is important to understand the accuracy and precision of visual methods of temperature estimation. Twenty-eight forensic and/or physical anthropologists estimated the temperature that fourteen bone samples had been subjected to based only on their colour via an online questionnaire. Bone samples shown in the questionnaire ranged from unheated to having been heated at 1200°C. Respondents were given two options to base their estimates on, resulting in a multi...

PLOS ONE

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 ...

Cadernos do GEEvH, 2012

The interdisciplinary research of burned bones is focused in this paper by presenting and discussing some methods that can assist the bioanthropologist in the analysis of this kind of remains. In particular, some techniques based on the histological structure of bone and on its molecular composition allow new ways of identifying burned human bone and of determining some aspects of the biological and ontological profile of an individual. A brief summary of those techniques is thus here presented.

International Journal of Osteoarchaeology, 2020

In the past, experimental research into the histomorphological examination of burned human bone has led to the creation of a criterion for assessing burning intensity, which can be used to infer firing conditions in both archaeological and forensic contexts. Current methods visually compare the microscopic alterations in burned bone with modern bone samples fired at known temperatures and durations. Despite the benefits of this approach, it is hindered by the use of qualitative analysis, which is subject to the expertise of the examiner. This paper reviews previous histomorphological studies of burned bone and presents a new protocol for producing burned bone thin sections. It also introduces quantitative petrography as an alternative statistical method for categorising burning intensity. Four categories of burning intensity were calculated based on the quantified heatinduced changes identified in a pilot study examining burned porcine bone. These categories were consistent with those produced using more traditional qualitative methods, demonstrating that the results produced in this pilot study are reliable.