Phosphatic crusts as macroscopic and microscopic proxies for identifying archaeological animal penning areas

This study introduces new macroscopic and microscopic evidence for identifying archaeological animal penning areas: phosphatic crusts. Despite the importance of herding activities for reconstructing the social, economic, and ecological aspects of ancient communities, evidence for animal penning areas has traditionally relied on faint architectural traces or microscopic indicators that are often challenging to identify in the field. By employing a multidisciplinary approach that combines field observations, geoarchaeology, lipid biomarker, and microbotanical analyses, this research examines the phosphatic crusts recently identified at the Middle Bronze Age (1650-1300 BCE) site of La Muraiola di Povegliano (Verona, north-eastern Italy). The analyses uncover the processes behind phosphatic crust formation, highlighting the key role of the concentration of animal ejecta in the cementation of the deposit by nanocrystalline partially carbonated hydroxylapatite. This multi-proxy approach further demonstrates that phosphatic crusts serve as crucial archives for investigating the use of space, livestock management (e.g., free grazing/confinement, livestock species, foddering), and human-animal-environment interactions. • Phosphatic crusts can be a reliable macroscopic indicator for livestock penning areas. • Livestock penning can form cemented deposits of partially carbonated hydroxylapatite. • Mineralisation of organic remains occurs rapidly after deposition. • Phosphatised deposits are significant archaeobotanical archives in well-drained contexts. • Guidelines for field identification and handling of phosphatic crusts are provided.