The shades of red: First chemical analysis of red paintings from Casa de Piedra de Roselló, Aldea Beleiro, SW Chubut, Argentine Patagonia

The rock art of Aldea Beleiro (SW Chubut, Argentine Patagonia) stands out for the remarkable consistency in the use of red shades, particularly in the motifs of the multi-site Casa de Piedra de Roselló. These motifs, attributed by relative chronology to different moments of the Holocene, present a striking chromatic continuity that challenges the distinction between change and persistence in paint production over a long human occupation sequence (ca. 10,000 years BP). To address this issue, this study employs a multi-analytical approach—combining SEM-EDS, Raman micro-spectroscopy, and FTIR micro-spectroscopy—to differentiate between red pigments at a chemical level. Our findings suggest that, despite the apparent homogeneity in color, the underlying chemical composition reveals a diverse range of paint preparation techniques, even within motifs of similar chronology. This variability highlights the complexity of paint production processes and underscores the need for further research to better understand the methods and choices involved in pigment management for rock art painting.