Nature and function of prehistoric plant-based artefacts: biomolecular approach

Abstract

Plant artefacts are an essential part of the perishable material culture of prehistoric societies, these artefacts contain important information about resource management, craftsmanship and the activities of past populations. However, they are poorly represented in the archaeological narratives due to the natural processes of degradation of organic matter. To preserve these artefacts and avoid their natural degradation, specific environmental contexts are needed, such as humid, dry or frozen contexts, or their mineralization or partial carbonization. As a result, only a limited number of contexts provide knowledge about the richness and diversity of plant use in the past. The methods commonly used to study plant artefacts focus on the study of the operational chain or production process of the artefacts, from obtaining plant raw materials to their use and disposal. However, there are gaps in our knowledge in relation to this production process and especially in relation to the function of organic artefacts. The objective of this thesis is to provide new knowledge about the process of making and the function of plant-based artefacts from the study of the organic substances associated with these artefacts. Although amorphous organic residues associated with these artefacts have occasionally been documented, only some studies have identified their molecular composition. This limits our understanding of the products that may have been associated, processed or stored in the artefacts of plant origin. This doctoral research focuses on the identification of materials and residue involved in the manufacture or use of artefacts of plant origin. It is the first study that integrates the analysis of organic residues in the operational chain of artefacts of plant origin from three archaeological settlements: La Cueva de Murciélagos (7986-3740 cal BC; Albuñol, Spain), La Draga (5324-4977 cal BC; Banyoles, Spain) and Dąbki 9 (5220-3580 cal BC, Dąbki, Poland). These sites present an exceptional preservation of organic elements, which allow an investigation into the preservation of organic residue in arid contexts, saturated with water and peatlands. The analytical methods used have been the morphological study of the objects, the visual and microscopic examination of the residues, their preliminary classification according to the aspect and the application of spectroscopy and spectrometry to analyse proteins and lipids. In addition, an experimental protocol has been implemented to reverse the consolidants applied to the La Draga artefacts during their post-excavation restoration and to be able to evaluate the presence of proteins in some of the residues identified in this collection. The results of this research provide a more complete picture of the practices of making and using the different artefacts. The results indicate that organic substances are introduced at different stages of the operational chain. It has been possible to identify adhesives and coatings, but also residues generated during use or consumption. In addition, this work improves our understanding of biomolecular preservation in different environments and highlights the need for a systematic examination of natural plant artefacts and their residues. Finally, questions to be explored in the future are proposed to contribute even more to the application of biomolecular archaeology to the analysis of artefacts made in plants.

Date of Award	22 May 2025
Original language	English
Supervisor	Isabelle Théry-Parisot (Director) & Raquel Pique Huerta (Director)