PhD in Tissue Remodeling and Postmortem Interval Estimation

Innovative Contributions of ¹⁴C Dating to Medico-Legal Expertise: Tissue Remodeling and Postmortem Interval Estimation

Profile and skills required
The desired profile is that of a PhD candidate holding a Master’s degree (or equivalent) in geochemistry / Earth sciences, archaeological sciences, analytical chemistry, physical chemistry, or biology with a strong emphasis on physico-chemical approaches. A strong and demonstrable interest in chemistry is essential, evidenced by hands-on laboratory experience. The candidate should also show a marked interest in radiocarbon dating. Skills in data analysis will be considered an asset, together with strong methodological rigour and a good command of scientific English. Finally, the project requires high motivation for a topic at the interface between analytical sciences and medico-legal applications, as well as the ability to work in an interdisciplinary environment where ethical considerations and operational constraints are integral to the research process.

Project description
When a body is discovered, estimating the postmortem interval (PMI) is a pivotal component of the medico-legal investigation: it helps clarify the circumstances of death, supports the identification of the deceased, and carries legal implications, as public prosecution in criminal matters is subject to statutory limitation periods. While early PMI estimation relies on well-established biological and physicochemical markers, advanced decomposition and skeletonization remain affected by substantial uncertainty due to the complex interplay of intrinsic factors (age, sex, physiological and pathological status) and extrinsic factors (deposition conditions, environment).
This doctoral project addresses a major international challenge by seeking to strengthen the medico-legal applications of radiocarbon dating in recent contexts (post-1950). The approach is grounded in exploitation of the atmospheric ¹⁴C peak induced by nuclear weapons testing in the 1950s–1960s (the “bomb pulse”), which provides an unparalleled chronological marker for estimating the formation dates of biological tissues. Despite its proven potential in archaeology, key limitations related to tissue remodeling, inter- and intra-individual variability, and the post-2010 convergence of atmospheric ¹⁴C levels remain insufficiently characterized for operational use.
The aim of this thesis is to improve the accuracy, robustness, and transferability of birth- and death-year estimation through a comparative multi-tissue strategy that explicitly integrates remodeling effects and is stratified by age and sex. The project’s originality lies in combining a reference collection of samples from documented individuals (sex, age, dates of birth and death, medical history), systematic multi-tissue sampling, and high spatial-resolution analyses. Sampling will be conducted on donor bodies from the Body Donation Program of the Lille Faculty of Medicine, within an approved ethical framework, and specimens will be maintained on the FATE experimental taphonomy platform. To broaden chronological coverage, the reference dataset will be supplemented with a recent osteo-archaeological series supported by rich contextual documentation.
For each individual, tissues with contrasting renewal kinetics will be collected (dental tissues, cortical bone, trabecular bone, keratinous tissues) in order to: (i) model the effect of remodeling on “lag time” (the discrepancy between true and estimated dates), (ii) refine conditions of applicability in recent individuals, and (iii) optimize sampling strategies in medico-legal and archaeological contexts. Radiocarbon measurements will be performed using accelerator mass spectrometry (AMS, MICADAS), adapted to heterogeneous biological matrices and very small sample masses. Methodological developments targeting incremental micro-samples will further enable investigation of inter- and intra-tissue variability in radiocarbon ages. The project aligns with the research priorities of ULR7367 and leverages a formalized strategic collaboration with the Laboratoire des Sciences du Climat et de l’Environnement (UMR 8212, CEA/CNRS/UVSQ) and the Centre de Recherche et de Restauration des Musées de France (Ministry of Culture), ensuring sample preparation, measurement, calibration, and data interpretation. Expected outcomes include operational recommendations (tissue selection, uncertainties, post-2010 applicability), remodeling-related correction models, and improved reliability for identification and dating in judicial contexts. By bridging geochemical expertise and medico-legal needs, the project will contribute to the scientific and methodological visibility of French research in forensic sciences.

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