The revelation of fossilized footprints, found in present-day New Mexico and publicized in 2021, sent shockwaves through the field of archaeology. These prints seemed to re-scribble a significant portion of humanity’s historical narrative. New research further bolsters the profound importance of this discovery.
The footprints, deceptive in their apparent freshness, were approximately 21,000 to 23,000 years old. This estimate was provided through radiocarbon dating of preserved seeds of an aquatic plant, deposited both above and below the footprints in the ancient, muddy soil.
The implications of this are monumental. It thrusts a wrench into the existing timeline of human history in the Americas – the last known region to have been discovered by prehistoric people. The 61 dated prints, which were unearthed in the Tularosa Basin, at the periphery of a primordial lake in White Sands National Park, suggest human habitation in that territory at a much earlier date than previously believed. Scientific consensus of the era suggests migration into North America was obstructed by omnipresent massive ice sheets, hinting towards a much-anticipated earlier arrival of humans in the region.
Nevertheless, the originally established age of the footprints was contested by several archaeologists. Skeptics argued that aquatic plants – like Ruppia cirrhosa utilized in the 2021 study – could assimilate carbon from waterborne atoms, potentially skewing towards an erroneously early date.
A subsequent study published in the journal ‘Science’, nevertheless, substantiated the initial dating with two new lines of evidence. “While the original study was still being scrutinized, we were already double-checking our results based on multiple strands of evidence,” confided Kathleen Springer, research geologist at the US Geological Survey and joint author of the study.
There is a longstanding, somewhat nebulous debate surrounding the first human migration to Americas, with the earliest estimates ranging from 20,000 years ago to as recent as 13,000 years. The scarcity and controversies around early archaeological evidence from the region, make these footprints invaluable relics of our past.
The dedicated follow-up study concentrated on radiocarbon dating of conifer pollen, circumventing the complexities of dating aquatic plants like Ruppia cirrhosa. The researchers managed to isolate around 75,000 grains of pollen from the same layers as the original seeds for each sample, achieving a similar age estimate as the seeds. Additionally, the team utilized the optically stimulated luminescence technique to ascertain the last period the fossil sediment’s quartz grains were exposed to sunlight, pinpointing their minimum age to 21,500 years.
“This study sheds light upon the magnificent story of human evolution, even though we still have much to uncover about the settlement of the Americas,” concluded Jeff Pigati, USGS geologist and co-lead author of the study.
Several enigmas still shroud the journey of the early humans into Americas. The mode of travel- whether by boat or land bridge- remains uncertain. The onset of advanced genetic evidence hasn’t clarified whether one or several early modern human populations made the arduous journey.
An associated commentary published alongside the study, however, affirms that despite the concerns, the new findings strongly suggest human habitation in the Americas during the Last Glacial Maximum- a period roughly between 19,000 and 26,000 years ago.
“The discovery of these footprints is a seismic event in our field. The Americas marked the final leg of modern humans’ worldwide journey,” espoused Jennifer Raff, an associate professor at the University of Kansas, and author of “Origin: A Genetic History of the Americas.” “Envisioning those pioneers facing the trials and opportunities presented to them by these unexplored lands is truly awe-inspiring.”
