Radiocarbon Dating of Ancient Rock Paintings

Abstract

A technique based on cold argon and oxygen plasmas permits radiocarbon dates to be obtained on paintings that contain inorganic pigments. (To listen to a podcast about this feature, please go to the Analytical Chemistry website at http://pubs.acs.org/journal/ancham.)Rock art images are among the most enigmatic and personal artifacts studied in paleoarchaeology. Rock paintings (pictographs) left by ancient prehistoric cultures are found all over the worldsvirtually everywhere there are rocks. One example of a polychrome painting in the lower Pecos River region of southwest Texas (where thousands of other impressive painted images are found on the limestone shelter walls) is shown in Figure 1. Two frequently asked questions are, without regard to location, how old is it and what does it mean? This review deals with attempts to answer the question of age.

Raman microscopy of prehistoric rock paintings from the Hoz de Vicente, Minglanilla, Cuenca, Spain

“…Post quem and ante quem dates for the pictorial event could be obtained in this way. [17,19,25] As indicated before, the marked background level observed in the spectra of the external layers may be ascribed to the content in clays. These results have been confirmed by EDX spectra obtained from these layers, Fig.…”

“…As anticipated previously, the detection of this patina in the sample 06/2008-HVip3:sus will enable achieving an ante quem date for the painting of the schematic line. [17,19,25] On the other hand, most of the Raman spectra obtained from the external face of the samples of this panel exhibit a noticeable background level due to fluorescence, Fig. 4(a).…”

“…This finding, as well as the detection of a patina of whewellite covering another pictograph, will enable obtaining significant radiocarbon 14 C AMS dates for these representations of the schematic art. [17,19,25] …”

Age of Barrier Canyon-style rock art constrained by cross-cutting relations and luminescence dating techniques

“…Our ability to test hypotheses and understand prehistory increases with each advance in geochronology, as experienced with AMS radiocarbon dating and U-series dating of rock art (4,7). In situations such as the Great Gallery pictographs where organic material is completely absent from pigments or contamination is an issue, or in the case of the countless petroglyphs directly etched into rock, age control has nevertheless remained elusive.…”

“…Interpretation of the origin and meaning of rock art is indirect at best, or simply speculative. In the case of some pictographs, pigments may include or have enough accessory carbon for accelerator mass spectrometry (AMS) radiocarbon dating (1)(2)(3)(4). In other special situations, such as caves, minimum age constraints have been obtained by various techniques of dating material that overlies or entombs rock art (5-7).…”