M/F Hidden history of triacylglycerols in archaeological pottery

Job Description

Thesis Subject

A – State of the art
Whilst food meets a primary physiological need of every living organism, in human societies it is also a vehicle for social organisation, the focus of cultural practices, and a repository of knowledge, skills and techniques. Exploring the dietary strategies of past populations is a challenging task, as these rely on the consumption of resources whose remains are only partially preserved in the archaeological record. Based on an original and unprecedented collaboration between archaeology and biochemistry, this PhD project aims to explore the informational potential of triacylglycerols (TAGs) preserved in African ethno-archaeological ceramics and in archaeological pottery from various European and African contexts, in order to overcome the challenges of identifying foodstuffs preserved within archaeological ceramic vessels, whether these be animal fats or plant-based substances.
Over the past few decades, the analysis of organic residues in archaeological pottery (ORA – Organic Residue Analysis) has seen significant methodological developments. These advances have enabled the identification of a wide variety of foodstuffs across different chrono-cultural areas. However, despite this progress, our understanding of ancient dietary strategies remains incomplete. We still lack robust, cross-cultural reference frameworks that would allow us to reliably attribute a function to archaeological pottery. Furthermore, the chemotaxonomic potential of certain biomarkers, such as triacylglycerols, remains largely untapped, depriving us of precise identification methods to distinguish the species from which animal fats or dairy products are issued, or to discriminate plant oils. Research into marine products also requires the removal of a number of methodological barriers.

B - Objectives
The objective of this project is to explore the chemotaxonomic potential of TAGs in an archaeological context in order to achieve accurate identification of the fats prepared and consumed in pottery, and to contribute to a better understanding of the dietary strategies of past populations. To achieve this objective, the project aims to overcome several major scientific and methodological barriers: i) to develop a reference database of modern fats in order to establish discrimination criteria based on their TAG composition; (ii) to develop and validate an innovative and robust LC-MS/MS analytical method dedicated to TAGs, and to implement multivariate statistical methods and appropriate machine learning techniques for the processing of large datasets; (iii) to assess changes in TAG signals resulting from food preparation in ceramic vessels and during the burial of pottery after it has been discarded.
This project is highly interdisciplinary. It draws on the fields of biochemistry and lipidomics, archaeology, ethnoarchaeology, experimentation, and statistical data analysis. Particularly innovative, it aims to open up new methodological avenues (molecular and isotopic) for the identification of foodstuffs of high symbolic, economic or nutritional value, such as dairy products, certain plant resources and substances of aquatic origin. The feasibility of this project is ensured by the existence of collections available at CEPAM: a collection of natural substances and ethnographic pottery from Senegal, and African and European archaeological ceramics that have yielded significant quantities of TAGs.

C – Methodological issues
The methodology developed will aim to overcome the obstacles outlined above by developing new approaches in lipidomics, structured around three complementary methodological strands: (i) the development of up-to-date reference frameworks based on the study of raw natural substances and residues from African ethnographic ceramics to provide robust and directly applicable interpretative models; (ii) conducting controlled experiments by studying the processes of TAG alteration using pottery of known function buried in sediments; (iii) detailed structural characterisation of TAGs preserved in archaeological vessels from Africa and Europe.
C1. Ceramic assemblages and reference substances
The implementation of this project requires access to (i) raw, contemporary natural substances, (ii) the same substances prepared in ethnographic ceramics under known conditions, (iii) experimental pottery that has been buried in a sedimentary environment, and (iv) archaeological sherds. In order to obtain all this material, we conducted surveys amongst the Bedik (Kedougou region) and Jóola Kaasa (Lower Casamance) communities, who still produce and use ceramics, particularly for the preparation of dishes based on plants (rice, fonio, sorghum, millet) and a variety of animal products (pork, fish) cooked using various fats (shea butter, palm oil). As part of the SINERGIA project Foodways in West Africa (2019–2024), funded by the Swiss National Science Foundation (FNS), over 600 vessels have been documented, raw materials collected and experiments conducted, highlighting the strong potential of TAGs for food preservation. Furthermore, vessels with known contents and functions were buried in Senegal for one year and then two years, in order to understand the fate of TAGs in a sedimentary context. Archaeological sites were also explored, yielding ceramics used over the last millennium, some of which still contain TAGs. Finally, several European archaeological samples proved to be rich in TAGs, and the methods established for the ethnographic samples can be tested on a diverse range of archaeological materials.

C2. Chemotaxonomic potential of TAGs
Preliminary work has enabled us to begin assessing the chemotaxonomic potential of TAGs for certain African and European plant-based substances (such as olive oil, palm oil, hazelnut oil and shea butter). However, the reference databases remain incomplete, whether for oils and dairy products (sheep, goat, cow) or, above all, aquatic resources. The project will focus primarily on these three categories. Substances of known nature and origin have already been collected in Africa, and others will be collected in Europe from livestock farmers, farmers and fishermen. The pottery to be analysed (available at CEPAM and the University of Geneva) will be selected in collaboration with teams from the UMR TEMPS, the University of Geneva (collab. Anne Mayor, ARCAN Laboratory) and Cheikh Anta Diop University in Dakar.

C3. Analytical strategy
As the analyses involved are destructive, it will be essential to minimise sampling in order to preserve the archaeological heritage. Where carbonised residues are visible on the surface of the pottery, these will first be examined at different magnifications using optical and electron microscopes. We will implement a single extraction protocol to carry out the entire analytical process. The samples will initially be analysed by GC-MS (Gas Chromatography coupled with Mass Spectrometry) at CEPAM to obtain an overall characterisation of the lipids and to specifically select samples containing TAGs. These will then be analysed in depth by LC-MS/MS (Liquid Chromatography coupled with tandem Mass Spectrometry) at the IPMC. For samples not containing TAGs, isotopic analyses may be carried out. The originality of the project lies in a reasoned and integrated combination of GC-MS and LC-HRMS/MS, a technique still rarely employed in biomolecular archaeology.

C4. Development of an LC-HRMS method for TAGs identification
One of the major obstacles to be overcome in the analysis of archaeological TAGs lies in their reliable identification, despite complex mixtures, co-elution phenomena and low-intensity signals. The project draws on the expertise developed at the IPMC in lipidomics using LC-HRMS/MS. The IPMC's contribution aims to develop an LC-HRMS/MS methodology dedicated to the detailed analysis of triacylglycerols, in order to significantly improve the robustness and accuracy of identifications. The first step will be to optimise liquid chromatographic separation for TAGs, minimising overlaps between closely related species (same exact mass but different fatty acid composition). This approach will overcome the limitations of analyses relying solely on exact mass or on methods not optimised for complex archaeological matrices.
The separated TAGs will be analysed by high-resolution mass spectrometry coupled with fragmentation (LC-HRMS/MS), using acquisition strategies designed to yield diagnostic fragment ions. Particular attention will be paid to the fragmentation profiles characteristic of substances of plant, terrestrial animal and aquatic origin, which remain poorly documented in an archaeological context. Ultimately, the aim is to propose an analytical strategy dedicated to TAGs. The data generated will be processed using specialised software (Lipidsearch and MS-Dial), supplemented by statistical approaches developed within the project. The ethnographic data will form a learning basis for the development of predictive models, which will be calibrated and evaluated to ensure their robustness and to provide a reliable and usable tool in the long term.

D – Expected results
By the end of this project, we hope to have made progress in understanding the fine structure of TAGs preserved in ceramics from different contexts and periods. The work carried out on ethnographic, experimental and archaeological collections will provide a better understanding of the processes of TAG alteration linked to food preparation, the use of vessels and post-depositional phenomena. Finally, the project aims to assess the chemotaxonomic potential of these compounds, even in a degraded state, in order to distinguish the origin of dairy products, differentiate between vegetable oils and better identify marine resources. This will inform us on the dietary strategies of West African populations over the last millennium, as well as enabling the criteria developed to be tested on TAG-rich ceramics from other contexts.
The results will be published in international journals. Given the interdisciplinary nature of the project, several journals may be targeted depending on the results obtained, such as Food Chemistry, Phytochemistry, J. of Lipid Research, J. of Archaeological Science or J. of Archaeological Method and Theory.

E – Integration of the PhD student into an international research group
This PhD research project, which lies at the intersection of lipid biochemistry and archaeology, forms part of an international research consortium funded by the CNRS. It forms part of a collaborative framework directly involving two CNRS laboratories where the PhD will be carried out the research, CEPAM in Nice and IPMC in Valbonne, drawing on the expertise of the TEMPS research unit in Nanterre, as well as collaborations with the University of Geneva (collaboration with Anne Mayor, ARCAN laboratory) in Switzerland and universities in Senegal (Cheikh Anta Diop University in Dakar and Assane Seck University in Ziguinchor).
The PhD student will be trained in the archaeological and ethno-archaeological aspects related to the functional study of ceramics, including an understanding of the contexts of production, use and alteration of pottery. This approach will be reinforced by the expertise of Julien Vieugué, a CNRS research fellow in archaeology, enabling the cross-referencing of material data and molecular signatures.
On the analytical front, the PhD student will participate in the comprehensive screening of lipid residues by GC-MS at CEPAM, including the selection and preparation of samples, data acquisition and initial interpretation. Samples containing TAGs will then be analysed by LC-HRMS/MS at the IPMC, where the PhD student will be involved in optimising chromatographic separations, MS/MS acquisition strategies and the analysis of fragmentation profiles, in order to contribute to the development of approaches dedicated to the detailed identification of TAGs. He or she will be trained in data processing and statistical analysis, working closely with the teams at CEPAM and IPMC, particularly in the implementation of specialised lipidomics tools and multivariate approaches, with Pauline Garberi, a CNRS engineer in computational science and statistics at CEPAM, in order to distinguish the lipid signatures of the substances under study.
Finally, the PhD student will be integrated into an international research network through the thesis's affiliation with the IRP STRATALIM project (2026–2030) and the 80PRIME project, which will help fund some of the scientific missions and facilitate exchanges, workshops and international collaborations.
Recommended reading
Correa-Ascencio M., Evershed R. P., 2014, High throughput screening of organic residues in archaeological potsherds using direct acidified methanol extraction. Analytical Methods 6, 1330-1340.
Craig O. E., 2021, Prehistoric Fermentation, Delayed-Return Economies, and the Adoption of Pottery Technology. Current Anthropology 62 (24), S233-S241.
Cramp, L., Evershed, R.P., 2014. Reconstructing Aquatic Resource Exploitation in Human Prehistory Using Lipid Biomarkers and Stable Isotopes, in: Treatise on Geochemistry. Elsevier, pp. 319–339.
Debels P., Drieu L., …., Malergue A., …., Sall M., Regert M., Mayor A., 2024, Investigating grandmothers' cooking: a multidisciplinary approach to foodways on an archaeological dump in Lower Casamance. Plos ONE 19 (5), e0295794.
Dias Araújo A. R., Buvry O., Antonny B., Debayle D., 2025, Separation of polar and neutral lipids from mammalian cell lines by high-performance thin-layer chromatography. Journal of Chromatography A 1741, 465610.
Drieu L. et al., 2025, A medium-throughput approach for improved taxonomic identification of lipids preserved in ancient pottery. Archaeometry 62 (1), 182-201.
Drieu L., Regert M., Mazuy A., Vieugué J., Bocoum H., Mayor A., 2022, Relationships between lipid profiles and use of ethnographic pottery: an exploratory study. Journal of Archaeological Method and Theory 29, 1294-1322.
Mirabaud S., Rolando C., Regert M., 2007, Molecular criteria for discriminating adipose fat and milk from different species by nanoESI MS and MS/MS of their triacylglycerols: application to archaeological remains. Analytical Chemistry 79, 6182-6192.
Prévost C., Drieu L., Pasqualini A., Regert M., 2023, The ARchaeological Organic residues Literature Database (AROLD): construction of a tool for reviewing and querying published lipid data in organic residue analysis. Archaeometry 65 (5), 1125.
Regert M., 2011, 2011, Analytical strategies for discriminating archaeological fatty substances from animal origin. Mass Spectrometry Reviews 30 (2), 177-220.
Sequera C., …, Debayle D.,…, 2025, FThe HDAC inhibitor romidepsin renders liver cancer vulnerable to RTK targeting and immunologically active. Nature Communications 16 (1), 7919.
Turini M., Mayor A., Vieugué J., Delvoye A., Sall M., Regert M., Drieu L., 2025, Unravelling ceramic content and organic coatings in Senegalese ethnographic pottery vessels. Journal of Archaeological Science: Reports 63, 105111.

Your Work Environment

This PhD project will be hosted by two laboratories: CEPAM (Cultures and Environments. Prehistory, Antiquity, Middle Ages), which is a joint CNRS–Université Côte d'Azur research unit located on the Saint-Jean-d'Angély campus in Nice, and the IPMC (Institute of Molecular and Cellular Pharmacology), located on the Sophia Antipolis campus in Valbonne and affiliated with the CNRS, Inserm and Université Côte d'Azur. Both laboratories are equipped to document archaeological material and take samples, as well as to carry out the chemical preparation and analysis of samples (an FTIR, a GC and two GC-MS units at CEPAM, and an LC-HRMS/MS and a GC-MS/MS unit at the IPMC).

Constraints and risks

Adhere to working hours, the allocation of machine time and the collective working environment, as well as safety requirements, both in the laboratory and in the field.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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