June 30, 2022
The astonishing discovery that points to human presence in the Americas much earlier than previously thought

The astonishing discovery that points to human presence in the Americas much earlier than previously thought

A team of scientists working in the southwestern United States has found human footprints dating back between 23,000 and 21,000 years

Photo: Bournemouth University/BBC News Brasil

New scientific findings indicate that humans reached the Americas at least 7,000 years earlier than previously expected.

Research at the moment when the American continent began to be populated by Asia has sparked deep debates for decades. Many researchers question evidence of human presence in North America over 16,000 years ago.

Now, a team of scientists working in the southwestern US state of New Mexico has found human footprints dating between 23,000 and 21,000 years ago.

This discovery has the potential to transform what is known and what was believed when the continent was inhabited. It indicates the existence of large migrations that we know nothing about and raises the possibility of the extinction of these populations.

The footprints that led to this new timeline formed in the soft mud of a lake that is now part of White Sands National Park.

To estimate the “age” of the footprints, the US Geological Survey team did carbon dating of the sediment layers above and below the footprints they found. Thus they can determine the “age” of the footprints themselves.

Based on the sizes of these brands, scientists suspect they are teens or children coming and going, sometimes accompanied by an adult.

It is not clear to scientists what exactly these people were doing there, but it is possible that they were helping adults with a hunting method that can be seen later in the indigenous cultures of North America. It is known as buffalo jumping and involves driving wild animals over a cliff.

Paleontologist Sally Reynolds, a researcher at Bournemouth University (UK), explains that these animals “need to be treated in a very short period of time”. “The flames must be lit, the grease must be separated.” Children and teens there may have helped the adults collect water, firewood, or other supplies.

“Omar” footprints

The dating of the discovery is the focus of debate. This is because it is not the first time that some new evidence about past human presence in the Americas has been announced. But almost all of them end up challenging in some way.

In general, the debate revolves around the following: Are stone tools found on a site really as ancient as they seem, or are they just rocks broken by some natural process, such as falling off a cliff?

The researcher records the images that will be used for 3D models of the footprints

The researcher records the images that will be used for 3D models of the footprints

Photo: Bournemouth University/BBC News Brasil

These potential artifacts are sometimes less visible than the exquisitely crafted 13,000-year-old spearheads later found in North America. This leaves the door open to controversies and final conclusions.

“One of the reasons there is so much controversy is that there is a real lack of strong, unambiguous data. That’s what we think we probably have now (about the presence of humans on the continent nearly 7,000 years earlier than previously thought).” , Professor Matthew Bennett, first author of the Bournemouth University article, tells BBC News.

“Footprints are not like stone tools. A footprint is a footprint and cannot be moved up and down [nas camadas do solo]. “

While the nature of the physical evidence here is as hard to dismiss or challenge as the spearhead, the researchers needed to ensure that the dating was literally watertight (completely closed to liquids).

A potential complication noted by Science, the scientific publication in which the results were published, was in the early stages of reviewing the discovery, was the “reservoir effect.” This indicates the way ancient carbon can sometimes be recycled in aquatic environments, interfering with radiocarbon findings by making the site appear older than it actually is.

However, the researchers say they have investigated this possibility and believe it is not significant here.

Tom Higham, a professor and specialist in radiocarbon dating at the University of Vienna, said: “They did some checks on the dates of material close to the footprint and found that all the terrestrial samples (coal) produced similar ages for the aqueous material dating back closer to the footprints.”

“They also argued, I think for good reason, that the lake must have been shallow by the time people walked there, mitigating the effect of reservoir effects introduced by ancient carbon sources.”

According to Higham, the consistency of the results and the support of a different dating technique applied to the place of discovery validate the findings.

“I think, taken together, this is a streak that lasted 21,000 to 23,000 years,” Higham told BBC News.

Controversies over dating in the americas

Controversies in early American archeology have much to do with the historical development of the scientific field.

During the second half of the twentieth century, a consensus emerged among North American archaeologists that people belonging to the Clovis culture were the first to reach the Americas.

A stone head made by the Clovis culture, believed to be the first wave of humans on the American continent

A stone head made by the Clovis culture, believed to be the first wave of humans on the American continent

Foto: Getty Images / BBC News Brasil

These great fishermen are believed to have crossed a land bridge over the Bering Strait, which connected Siberia to Alaska during the last Ice Age, when sea levels were much lower.

Clovis was the name of an archaeological site so named, and it was discovered in 1939, also in New Mexico. At the site, chipped stone artifacts dating back 11,400 years were found. According to this theory, supported mainly by the American archaeological community, the arrival occurred about 12 thousand years ago.

On the one hand, if the “Clovis first” consensus was consolidated, on the other hand, the discoveries of ancient human existence ended up being unreliable. This has even led some archaeologists to virtually stop looking for signs of the previous occupation.

But in the seventies this doctrine began to be questioned.

In the 1980s, strong evidence of a 14,500-year-old human presence appeared in Monte Verde, Chile.

Since the 2000s, other pre-Clovis sites have become widely accepted, such as the 15,500-year-old Buttermilk Creek complex in central Texas and the 16,000-year-old Cooper’s Ferry site in Idaho. Both are in the United States.

Researchers analyze sediments in the footprint area of ​​White Sands, New Mexico

Researchers analyze sediments in the footprint area of ​​White Sands, New Mexico

Photo: Bournemouth University/BBC News Brasil

Now, the New Mexico footprints indicate that humans reached the interior of North America at the height of the last Ice Age.

“He found no fault in the work that was done or the explanations for this article, which is significant and provocative,” said Gary Haynes, professor emeritus at the University of Nevada.

“The passes lie so far south of the Bering terrestrial connection that we now have to ask ourselves (1) whether people or their ancestors (or others) crossed from Asia to the Americas long before, (2) whether people moved quickly across continents after every crossing, and (3) if they leave any offspring.”

Andrea Manica, a geneticist at the University of Cambridge, said the discovery of footprints in New Mexico will have important implications for the history of the population of the Americas.

One of the footprints that researchers attribute to children or adolescents who lived more than 20 thousand years ago in the American continent

One of the footprints that researchers attribute to children or adolescents who lived more than 20 thousand years ago in the American continent

Photo: Bournemouth University/BBC News Brasil

“I can’t comment on the reliability of dating because it’s outside my purview, but strong evidence for humans in North America 23,000 years ago is inconsistent with genetics, which clearly shows Native Americans split from Asians at roughly 15,000 to 16,000 years ago.”

“This suggests that the first settlers in the Americas were replaced when the ice corridor formed and another wave of settlers entered. But we have no idea how that actually happened.”