Rock Art uranium-thorium and radiocarbon cross-dating at Altamira cave, Spain

A groundbreaking cross-dating study of uranium-thorium (230Th/234U) and radiocarbon (14C) methods on secondary carbonate layers from Altamira cave, Spain, reveals that 230Th/234U ages can be misleadingly older due to radionuclide mobilization. The research, analyzing milligram-scale samples from the same carbonate fractions, found that while some 230Th/234U dates aligned with archaeological evidence (20-23 ka Cal BP), others were skewed by uranium loss. This suggests multiple periods of cave art activity in Altamira, including the late Gravettian/early Solutrean phases, while confirming earlier radiocarbon dating of bison charcoal. The study underscores the necessity of cross-dating to validate accurate age determinations for parietal deposits.

Pons-Branchu, E., Levier, M., Tisnérat-Laborde, N., Thil, F., Dapoigny, A., & Valladas, H. (2026). Rock Art uranium-thorium and radiocarbon cross-dating at Altamira cave, Spain. Quaternary Science Reviews, 379, 109900. https://doi.org/10.1016/j.quascirev.2026.109900