Guest “another paradigm bites the dust” by David Middleton
For quite some time it has been “settled science” that humans migrated into the Americas during deglaciation as ice-free passages opened. While there have been indications that humans may have arrived much earlier, we now have “rock solid” evidence that humans were already in New Mexico about 23,000 years ago.
Earliest evidence of human activity found in the Americas, researchers report
Date: September 23, 2021
Source: University of Arizona
Summary: Footprints at White Sands National Park in New Mexico confirm human presence over at least two millennia, with the oldest tracks dating back 23,000 years, say scientists.
Footprints found at White Sands National Park in New Mexico provide the earliest unequivocal evidence of human activity in the Americas and provide insight into life over 23,000 years ago, scientists report.
The findings are described in an article in the journal Science.
Researchers Jeff Pigati and Kathleen Springer, with the U.S. Geological Survey, used radiocarbon dating of seed layers above and below the footprints to determine their age. The dates range in age and confirm human presence over at least two millennia, with the oldest tracks dating back 23,000 years.
This corresponds to the height of the last glacial cycle, during something known as the Last Glacial Maximum, and makes them the oldest known human footprints in the Americas.
It was previously thought that humans entered America much later, after the melting of the North American ice sheets, which opened up migration routes.
“Our dates on the seeds are tightly clustered and maintain stratigraphic order above and below multiple footprint horizons — this was a remarkable outcome,” Springer said.
The footprints tell an interesting tale of what life was like at this time. Judging by their size, the tracks were left mainly by teenagers and younger children, with the occasional adult.
“The footprints left at White Sands give a picture of what was taking place, teenagers interacting with younger children and adults,” said lead study author Matthew Bennett from Bournemouth University in England. “We can think of our ancestors as quite functional, hunting and surviving, but what we see here is also activity of play, and of different ages coming together. A true insight into these early people.”
“For decades, archaeologists have debated when people first arrived in the Americas,” said co-author Vance Holliday, a professor in the UArizona School of Anthropology and Department of Geosciences. “Few archaeologists see reliable evidence for sites older than about 16,000 years. Some think the arrival was later, no more than 13,000 years ago by makers of artifacts called Clovis points. The White Sands tracks provide a much earlier date. There are multiple layers of well-dated human tracks in streambeds where water flowed into an ancient lake. This was 10,000 years before Clovis people.”
Unfortunately, the paper is pay-walled, only the abstract is avaiable.
Early footsteps in the Americas
Despite a plethora of archaeological research over the past century, the timing of human migration into the Americas is still far from resolved. In a study of exposed outcrops of Lake Otero in White Sands National Park in New Mexico, Bennett et al. reveal numerous human footprints dating to about 23,000 to 21,000 years ago. These finds indicate the presence of humans in North America for approximately two millennia during the Last Glacial Maximum south of the migratory barrier created by the ice sheets to the north. This timing coincided with a Northern Hemispheric abrupt warming event, Dansgaard-Oeschger event 2, which drew down lake levels and allowed humans and megafauna to walk on newly exposed surfaces, creating tracks that became preserved in the geologic record. —AMS
Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. Questions remain about when and how people migrated, where they originated, and how their arrival affected the established fauna and landscape. Here, we present evidence from excavated surfaces in White Sands National Park (New Mexico, United States), where multiple in situ human footprints are stratigraphically constrained and bracketed by seed layers that yield calibrated radiocarbon ages between ~23 and 21 thousand years ago. These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna.
This follows on the 2020 publication of evidence that humans were in Mexico between 26,500 and19,000 years ago, possibly pushing back human dispersal into the Americas to 33,000–31,000 years ago (Ardelean et al, 2020).
Ardelean, C.F., Becerra-Valdivia, L., Pedersen, M.W. et al. Evidence of human occupation in Mexico around the Last Glacial Maximum. Nature 584, 87–92 (2020). https://doi.org/10.1038/s41586-020-2509-0
Bennett, Matthew R., David Bustos, Jeffrey S. Pigati, Kathleen B. Springer, Thomas M. Urban, Vance T. Holliday, Sally C. Reynolds, Marcin Budka, Jeffrey S. Honke, Adam M. Hudson, Brendan Fenerty, Clare Connelly, Patrick J. Martinez, Vincent L. Santucci, Daniel Odess. “Evidence of humans in North America during the Last Glacial Maximum”. Science, 2021; 373 (6562): 1528 DOI: 10.1126/science.abg7586
University of Arizona. “Earliest evidence of human activity found in the Americas, researchers report.” ScienceDaily. ScienceDaily, 23 September 2021. <www.sciencedaily.com/releases/2021/09/210923161340.htm>.