Mind-Blowing Discovery: Ancient Footprints Rewrite History of Humans in the Americas

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The revelation of fossilized footprints found in present-day New Mexico created an explosion of excitement in the field of archaeology in 2021. It appeared to rewrite a crucial part of the human narrative. Excitingly, recent research is now providing additional proof of their profound importance.

The footprints, although appearing recent, were actually imprinted into mud approximately 21,000 to 23,000 years ago. This revelation, based on radiocarbon dating of preserved aquatic plant seeds found above and below the fossils, significantly extends the timeline of human history in the Americas. The discovery of 61 dated prints in the Tularosa Basin, near a former lake in White Sands National Park, suggests that humans settled in the region prior to what was previously believed, contradicting the idea that massive ice sheets had prevented human migration into North America.

A single human footprint at the site.

National Park Service

Nevertheless, the authenticity of the footprints discovered in the initial findings came under scrutiny from certain archaeologists. Skeptics raised doubts about their age, pointing out that aquatic plants like Ruppia cirrhosa, as used in the 2021 study, can absorb carbon from dissolved atoms in the water instead of the air. This could lead to a potentially inaccurate early estimation.

In a follow-up study published Thursday in the journal Science, researchers said they have produced two new lines of evidence to support their initial dates.

Human footprints infilled with white gypsum sand at White Sands National Park.

National Park Service

Kathleen Springer, research geologist at the US Geological Survey and co-lead author of the new Science paper, emphasized the team's commitment to scientific rigor, stating, "While the original work was being published, we actively pursued testing our results using a variety of evidence. We had full confidence in our original age determinations, supported by compelling geological, hydrological, and stratigraphic evidence. However, we recognized the importance of obtaining independent chronological validation."

and gaining a better understanding of when and how early humans migrated to the Americas has been a topic of ongoing debate. The timing of the first inhabitants is estimated to be between 13,000 and 20,000 years ago, although there is limited and disputed archaeological evidence to support these claims. Therefore, the study and analysis of ancient footprints hold significant significance in validating the presence and dating of human settlements in the region.

In their subsequent study, the researchers concentrated on using radiocarbon dating of conifer pollen instead of aquatic plants like Ruppia, as stated in the news release.

For each sample, the scientists successfully identified and isolated approximately 75,000 grains of pollen from the same layers as the original seeds. A substantial amount of grains is necessary to obtain the required mass for a single radiocarbon measurement. The age of the pollen corresponded with that of the seeds.

A trench at the study site with David Bustos, White Sands National Park's resource program manager, in the foreground.

The team utilized an optically stimulated luminescence dating technique to ascertain the most recent period when sunlight reached the fossil sediment's quartz grains. This technique indicated that the quartz had a minimum age of 21,500 years.

"The initial response from certain sectors of the archaeological community was skepticism regarding the accuracy of our dating, which hindered the extraordinary assertion that humans existed in North America during the Last Glacial Maximum," shared Jeff Pigati, co-lead author of the study and geologist at USGS. "Nonetheless, our focused approach in this latest research proved highly fruitful."

While this study sheds light on the extensive narrative of human evolution, there are still numerous uncertainties regarding the colonization of the Americas.

It remains uncertain as to whether early humans reached their destinations through maritime means or by traversing a land bridge from Asia. Furthermore, despite significant developments in genetic analysis, it remains unclear whether a single populace or multiple populations of early modern humans undertook this arduous migration.

According to Bente Philippsen, an esteemed associate professor and specialist in radiocarbon dating at the Norwegian University of Science and Technology, establishing the age of pollen grains is a complex procedure that carries the potential for contamination.

Mandatory Credit: Photo by Thomas Dressler/imageBROKER/Shutterstock (5512321a)

A hot-air balloon, floating above the NamibRand Nature Reserve in Namibia, captures an image of a vehicle from the balloon ground crew traversing a sandy plain. The plain is adorned with fascinating Fairy Circles, situated on the edge of the captivating Namib Desert.

Thomas Dressler/imageBROKER/Shutterstock

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Furthermore, in a commentary published alongside the study, she emphasized that luminescence-based dates often come with significant measurement uncertainties. Despite this, she stated that the overall findings of the new study strongly suggest the existence of human presence in the Americas during the Last Glacial Maximum. This period, occurring between 19,000 and 26,000 years ago, witnessed the coverage of two massive ice sheets that extended as far as New York City, Cincinnati, and Des Moines, Iowa in the northern third of North America.

The extreme ice and cold temperatures during that period would have rendered a journey between Asia and Alaska impracticable, suggesting that the individuals who left these footprints likely arrived significantly earlier.

Jennifer Raff, an associate professor at the University of Kansas and the author of "Origin: A Genetic History of the Americas," expressed enthusiasm and acknowledged the significance of the footprint discoveries in the field.

In an email, she expressed that the American continents marked the final stage of humans' worldwide journey, highlighting the intrigue surrounding the experiences of venturing into unfamiliar territories and navigating the unique obstacles and possibilities they offered.