U/Th and 14C Crossdating of Parietal Calcite Deposits: Application to Nerja Cave (Andalusia, Spain) and Future Perspectives

14C and U/Th methods were used to date three thin carbonate layers deposited on decorated walls of Nerja Cave (Malaga, southern Spain) in order to constrain the age of the parietal non-figurative marks situated under these carbonate layers. Modern formations were also dated to estimate the detritic contribution for the U/Th method and the dead carbon proportion for 14C dating. We sampled two locations with ocher painting marks. In one case (mark 1), the good agreement between the ages obtained by the two methods suggests that the sample was not subjected to post-deposition alteration and that the results are reliable. In the other case (mark 2), the age discrepancy between the two methods reached 30,000 yr, indicating that geochemical alteration had affected the sample and that one or both results were inaccurate. The ages for mark 1 indicate that this type of non-figurative representation is older than 25,000 cal BP and that it can be associated with the oldest attested Paleolithic occupation of Nerja Cave