Mass spectrometric radiocarbon dates from three rock paintings of known age

Radiocarbon age determinations are presented on three hieroglyphic texts fr om Naj Tunich cave in Guatemala containing Maya calendar dates. The ages ob tained are on average 110-140 years older than the calendar dates. Several possible reasons are discussed for this discrepancy: one that is applicable to all radiocarbon dates on charcoal, one that applies to rock paintings, and one that is specific for the tropics. Possible problems with the ages a scribed to the Maya calendar dates are also discussed. Even with the potent ial problems that may exist, these dates still fall within 110-140 years of the ascribed calendar dates. Caution is urged in the interpretation of dat es on charcoal pigments from rock paintings; consideration of the "old wood " and "old charcoal" factors is important.