Same anthropogenic activity, different taphonomic processes: A comparison of deposits from Los Husos I & II (Upper Ebro Basin, Spain)

Sediments from archaeological deposits can be affected both by human activity and environmental agents after deposition. As a result, physical and chemical alterations can be recognized in the stratigraphical record. This work focuses on characterizing and comparing the post-depositional alterations that have affected prehistoric stall deposits from two neighbouring rockshelters located in the Upper Ebro Basin: Los Husos-II (ca. 4450–3790 cal. BC) and Los Husos-I (ca. 2210–1620 cal. BC). Micromorphological and fluorescence microscopy analyses applied on ash, dung, plant remains and geogenic parent material allow disentangling the origin and formation processes of physical–mechanical and physicochemical taphonomic features from both sites. Identification of truncation interfacies, compaction, bioturbation and mechanical effects by water among physical alterations, together with evidence of weathering, redistribution, and neoformation of phosphorous, calcium, iron and manganese-rich features makes it possible to assess the dynamics of the stabling sediments after their accumulation.