By Kennedy Maize
New research by a team led by the Interior Department’s U.S. Geological Survey has found that humans inhabited an area now part of the White Sands National Park in New Mexico more than 20 thousand years ago during what is known as the “Last Glacial Maximum,” (LGM) the planet’s last ice age. They also experienced rapid climate change.
artist’s rendering
According to an abstract of the research published this month in the journal Science Advances, “This well-dated and highly resolved paleoclimate record provides compelling evidence that humans in North America experienced marked environmental changes during the Last Glacial Maximum.” Science Advances is an open-access multidisciplinary journal published by the American Association for the Advancement of Science.
The researchers examined human footprints, domestic and wild animal tracks, and trails left by travois — wheel-less transport sleds — combined with advanced radiocarbon dating of a variety of vegetation including pollen. That evidence established a date for the site “between 23.5 and 21.7 thousand years ago.”
The researchers concluded, “Biomarker, pollen, and stratigraphic evidence indicate a complete overturning of the environment from a perennial lake to a playa and capture a large aridification episode…which shrank pluvial Lake Otero and allowed people to traverse the former shoreline area for nearly two millennia.”
A news release from the University of Arizona, whose researchers participated in the White Sands study, said the work “reveals a dynamic environment indicating the humans who left their tracks along an ancient lake shore experienced abrupt changes in temperature and water availability within their lifetimes.”
Five years ago, the USGS White Sand researchers reported that their work at the site established that the footprints they found were, according to a 2023 USGS news release, “between 21,000 and 23,000 years old. This discovery pushed the known date of human presence in North America back by thousands of years and implied that early inhabitants and megafauna co-existed for several millennia before the terminal Pleistocene extinction event.”
In the 2023 news release, said USGS, “In a follow-up study, published today in Science, researchers used two new independent approaches to date the footprints, both of which resulted in the same age range as the original estimate.” The long-held explanation that humans arrived in North America via an ice bridge from northern Asia during the LGM has been repeatedly debunked.
Jessica Tierney, a University of Arizona professor who was a co-author of the research paper, said, “The White Sands sediments are unique in that they allow us to reconstruct environmental conditions during the last ice age at a very high temporal resolution, so that we can see fluctuations that were relevant for the humans present at that time.”
Tierney said the analysis of the evidence found at the White Sands site “tells us that local changes in aridity at White Sands were quite large and followed global climate shifts.”
Kathleen Springer, USGS research geologist and lead author of the paper, said, “This study fulfilled a long-term research goal at White Sands – to expand the originally published footprint site and sample for environmental indicators to help further our understanding of the complete context of conditions at the height of the Last Glacial Maximum. It’s remarkable that early humans in the region were real-time witnesses to a rapidly changing environment discernible within a human lifetime – that is really food for thought.”
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