Humans Arrived in the Americas Much Earlier Than Previously Thought

The fossilized footprints discovered in New Mexico in 2021 have revealed that humans arrived in the Americas far earlier than previously thought. A recent study has further bolstered the significance of these ancient tracks, offering valuable insights into their early presence.

Radiocarbon dating of seeds from an aquatic plant found both above and below these footprints has yielded a surprising revelation. These imprints are from between twenty-one thousand to twenty-three thousand years ago.

This revelation prolongs the timeline of human existence in the Americas, the last continent known to have been inhabited by prehistoric populations. The sixty-one dated footprints, unearthed in the Tularosa Basin near an ancient lake within White Sands National Park, suggest that humans settled in the region far earlier than previously assumed.

Many scientists previously believed vast ice sheets blocked human migration into North America during this period. However, initial doubts were raised regarding the accuracy of dating these ancient footprints.

Some experts contended that dating might be compromised due to sources of carbon associated with aquatic plants, such as Ruppia cirrhosa. It can absorb carbon from dissolved atoms in water, potentially resulting in misleading dates.

To address these concerns, a subsequent study published in the journal Science has introduced two additional lines of evidence that corroborate the initial dating.

 

A set of children's footprints left in New Mexico around 22,500 years ago provides even more evidence towards an earlier human arrival in the Americas than once believed. https://t.co/IO85yFqS4X pic.twitter.com/Ga3xPCvI1O

— Long Now Foundation (@longnow) October 4, 2021

The first humans arrived in the Americas at least 21,500 years ago

This study holds significance in shedding light on the longstanding debate surrounding timing and methods of early human migration to the Americas. Estimates for the arrival of the first inhabitants have ranged from 13,000 to over 20,000 years ago, with limited and contentious archaeological evidence complicating matters. Consequently, the fossilized footprints assume paramount significance.

Researchers turned to radiocarbon dating of conifer pollen, derived from terrestrial plants, as a more reliable alternative to dating aquatic plants. They successfully established the congruence between the ages of the pollen samples and those of the seeds from the original study, thereby verifying the age of the footprints.

Furthermore, they employed optically stimulated luminescence. This dating technique examines the last exposure of quartz grains in the fossil sediment to sunlight, suggesting a minimum age of 21,500 years.

While this research illuminates the broader narrative of human evolution, significant questions persist. The precise means by which early humans reached the Americas—whether by watercraft or via a land bridge from Asia—remains uncertain. Additionally, despite advancements in genetic evidence, ambiguity remains regarding whether it was a single or multiple populations of early modern humans that undertook this formidable journey.