Characterisation of the bone–sedimentary matrix interface and its influence on mechanical cleaning

ABSTRACT The study of archaeological or palaeontological bone material often requires a preliminary cleaning treatment to remove the sedimentary matrix adhering to the specimen surface. The characteristics of this matrix and its interaction with the bone material determine the methods to be applied. However, the impact of this interaction on the effectiveness of cleaning treatments has received little attention. This study aims to characterise bone cortical preservation, the surrounding sedimentary matrix and their interaction at the contact interface, to understand how these factors influence the cleaning process and outcome. Specimens from three sites, each with carbonated concretions requiring similar cleaning methods, were included in the study. Despite the use of comparable techniques, different levels of impact were observed after cleaning. A combination of qualitative and quantitative methods was used to characterise the three factors: optical and electron microscopy, micro‐computed tomography, X‐ray diffraction and Fourier‐transform infrared spectroscopy. The results show that variability in the degree of interaction between the concretion and the bone can influence the cleaning process, even when the specimens initially appear to have similar characteristics. These findings provide valuable insights for optimising cleaning treatments and understanding their impact on subsequent analyses, with significant implications for zooarchaeological and taphonomic research.