Independent age estimates resolve the controversy of ancient human footprints at White Sands
Editor’s summary
Traditionally, researchers believed that humans arrived in North America around 16,000 to 13,000 years ago. Recently, however, evidence has accumulated supporting a much earlier date. In 2021, fossilized footprints from White Sands National Park in New Mexico were dated to between 20,000 and 23,000 years ago, providing key evidence for earlier occupation, although this finding was controversial. Pigati et al. returned to the White Sands footprints and obtained new dates from multiple, highly reliable sources (see the Perspective by Philippsen). They, too, resolved dates of 20,000 to 23,000 years ago, reconfirming that humans were present far south of the ice sheets during the Last Glacial Maximum. —Sacha Vignieri
Abstract
Human footprints at White Sands National Park, New Mexico, USA, reportedly date to between ~23,000 and 21,000 years ago according to radiocarbon dating of seeds from the aquatic plant Ruppia cirrhosa. These ages remain controversial because of potential old carbon reservoir effects that could compromise their accuracy. We present new calibrated 14C ages of terrestrial pollen collected from the same stratigraphic horizons as those of the Ruppia seeds, along with optically stimulated luminescence ages of sediments from within the human footprint–bearing sequence, to evaluate the veracity of the seed ages. The results show that the chronologic framework originally established for the White Sands footprints is robust and reaffirm that humans were present in North America during the Last Glacial Maximum.
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Science
Volume 382 | Issue 6666
6 October 2023
6 October 2023
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Copyright © 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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Received: 7 March 2023
Accepted: 10 August 2023
Published in print: 6 October 2023
Acknowledgments
Science is a way of knowing, and we acknowledge that there are many ways of knowing. Therefore, we deeply appreciate the perspectives, cultural practices, and oral histories of the tribes and pueblos whose homeland is in southern New Mexico. In addition, we thank White Sands National Park Superintendent M. F. Sauter and the park staff for their support of our research. We also thank P. Henne (US Geological Survey) for preliminary analysis of the pollen assemblages, C. Hassel (Flow Cytometry Resource Facility, Indiana University) for performing the flow cytometry, and T. Brown (Lawrence Livermore National Laboratory) and M. Springer (University of California, Riverside) for helpful discussions. We also thank A. Hudson and M. Berry (both US Geological Survey) and three anonymous reviewers for providing constructive reviews of this manuscript. This study was conducted under National Park Service permits issued to K.B.S. and J.S.P. (WHSA-2021-SCI-0002) and to D.O. (WHSA-2021-SCI-0001). This work was also performed partly under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This is LLNL-JRNL-844446. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US government.
Funding: Funding for J.S.P., K.B.S., and J.S.H. was provided by the US Geological Survey’s Climate Research and Development Program and by the US Geological Survey–National Park Service Natural Resources Preservation Program. Funding for D.W. and M.R.C. was also provided by the US Geological Survey’s Climate Research and Development Program. M.R.B. acknowledges the Arts and Humanities Research Council (AH/X001326/1). D.B. and M.R.B. thank the Western National Parks Association for support.
Author contributions: J.S.P. and K.B.S. conceptualized the project and completed the field work. J.S.H., D.W., M.R.C., and S.R.H.Z. performed the pollen analysis and radiocarbon laboratory work, and H.J.G. performed the luminescence laboratory work. The original manuscript was drafted by J.S.P. and K.B.S. Editing of the manuscript was done by J.S.P., K.B.S., J.S.H., D.W., M.R.C., S.R.H.Z., H.J.G., V.L.S., D.O., D.B., and MRB.
Competing interests: The authors declare no competing or conflicting interests.
Data availability: Downloadable files of the data presented in the supplementary materials (tables S1 and S2) can be found at (33).
License information: Copyright © 2023 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original US government works. https://www.science.org/about/science-licenses-journal-article-reuse
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Arts and Humanities Research Council: AH/X001326/1
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