Proceedings of the National Academy of Sciences
National Academy of Sciences
We welcome this further discussion of our results on the age of the Great Gallery rock art in the Canyonlands of Utah. The comment by Simon and Reed (1) focuses on just one of the three components of our study (2), which is presented in greater technical detail in ref. 3 and is surely our best-constrained and least-surprising result: the dating of a rock-fall that removed some of the art and thus provides a minimum age. Simon and Reed (1) point out that the Great Gallery panel is not pristine and relate the sordid human history of visitation and possible disturbance to the site. Indeed, being aware of this during our research, one of our initial hypotheses was that the rock fall may be historic. Despite the possibility of recent disturbance to some of the talus boulders, our results document that the rock fall occurred ∼900 y ago, and for the boulder we sampled a scenario of historic disturbance and exposure such as postulated by Simon and Reed (1) can be ruled out.
Pederson, J. L., Chapot, M. S., Simms, S. R., Sohbati, R., Rittenour, T. M., Murray, A. S. 2014. Reply to Simon and Reed: Independent and converging results rule out historic disturbance and confirm age constraints for Barrier Canyon rock art. Proceedings of the National Academy of Sciences (PNAS) https://doi.org/10.1073/pnas.1421319112