T01_02

NIR-imaging and Radiocarbon dating together for making the invisible visible. A non-destructive visualization of collagen before attempting a radiocarbon date

Catelli E¹,  Malegori C², Sciutto G¹, Oliveri P², Prati S¹, Benazzi S³, Cercatillo  S⁴, Paleček D⁴, Mazzeo R¹, Talamo S^4,5

¹University of Bologna, Department of Chemistry “G. Ciamician”, Ravenna Campus, Via Guaccimanni, 42, 48121, Ravenna, Italy, ²University of Genova, Department of Pharmacy, Viale Cembrano 4, I-16148, Genova, Italy, ³University of Bologna, Department of Cultural Heritage, Ravenna Campus, Via Degli Ariani, 1, 48121, Ravenna, Italy, ⁴University of Bologna, Department of Chemistry “G. Ciamician”, Via Selmi, 2, 40126, Bologna, Italy, ⁵Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany

Many archaeological rarest bones (human remains and precious bone objects) from Prehistory are enormously precious and are considered a cultural and historical patrimony. Radiocarbon dating is a well-established technique that estimates the age of bones by analyzing the collagen content. However, it is a destructive method and must be limited. In this study, we use imaging technology to visualize the presence of collagen on bone samples in a non-destructive way, hence minimizing the destruction of precious samples submitted to radiocarbon dating. The technique is near-infrared hyperspectral imaging (NIR-HSI).

NIR-HSI was used with a chemometric model to create chemical images of collagen distribution in ancient bones. The model also quantifies the collagen at every pixel and thus answering the questions: what, how much, and where.

Sixty archaeological samples (from the modern age to >50,000 years ago) have been used for developing the predictive model for quantifying collagen, based on partial least squares (PLS) regression. The amount of collagen in the selected bones was previously determined through the pretreatment of bone for the extraction of collagen for radiocarbon analysis. The model was validated using Cross-Validation (CV) and an independent test set of NIR-HSI bone images. The method represents a sustainable pre-screening approach for identifying sampling points for subsequent specific analyses, such as ¹⁴C dating.

Since the cultural heritage represents the testimony of past civilizations, our result will provide a significant advance not only for the study of human evolution but also for protecting and enhancing European cultural heritage.