New Discoveries Imply Man Arrived in the Americas 26,500 Years Ago

The early inhabitants of North America left behind precious few clues of their existence – a footprint here, a weapon and a mummy there – leading scientists to wonder exactly when the first people arrived on the continent. 

Now, two new studies report a stunningly early date: Humans may have been living on the continent at least 30,000 years ago.

That would mean that the first North Americans may have arrived before the Last Glacial Maximum (LGM), between about 26,500 and 19,000 years ago, when ice sheets covered much of what is now the northern U.S. and Canada.

However, humans didn’t become widespread on the continent until about 14,700 years ago, when the population boomed. 

“These are fascinating studies,” said William Harcourt-Smith, a paleoanthropologist at Lehman College and the American Museum of Natural History, both based in New York City, who wasn’t involved with the research.

“It’s now very clear that modern humans were in the Americas far earlier than we used to think. There have been other sites and scholars suggesting this, but it is rigorous studies like this that really seals the deal.”

In one study(opens in new tab), archaeologists analyzed a remote cave in northwestern Mexico containing human-made stone tools that are up to 31,500 years old, according to dating models. This would push back dates for human dispersal into North America to as early as 33,000 years ago, the researchers said. 

In the other study(opens in new tab), archaeologists took already-published dates from 42 archaeological sites in North America and Beringia and plugged them into a model that analyzed human dispersal. This model found an early human presence in North American dating to at least 26,000 years ago. 

Both studies, published on July 2020 in the journal Nature, go against the “Clovis-first” model, a decades-old hypothesis that early humans arrived in the Americas via Beringia as the last ice age was ending, about 13,000 years ago.

However, scientists have been chipping away at this model for years, as even older sites, including the newly analyzed cave in Mexico, are discovered and dated. 

Cave in the mountains

In 2010, researchers found ancient stone tools in Chiquihuite Cave, a site in the mountains that sits 9,000 feet (2,740 meters) above sea level and about 3,200 feet (1,000 m) above the valley floor, the researchers wrote in the study.

The terrain at the cave is challenging to navigate – the roof at the cave’s entrance collapsed about 12,000 years ago, sealing it off – so the team did excavations about 165 feet (50 m) inside the cave.

It was so hard to travel to and from the cave, that the archaeologists ended up living at the site for two seasons – a total of 80 days – in 2016 and 2017.

During that time, the team worked steadily, collecting bone, charcoal and sediment. They used two techniques to date the roughly 1,900 stone tools in the cave:  radiocarbon dating and optically stimulated luminescence (OSL).

With OSL, researchers assessed when quartz grains in the sediment had last been exposed to sunlight. To avoid biasing the results, “when we extracted the samples, it had to be in complete darkness,” said study lead researcher and director of the excavation, Ciprian Ardelean, an archaeologist at the Autonomous University of Zacatecas. 

The radiocarbon dating and the OSL dates matched, suggesting that the dating was accurate, Ardelean said. Then, the researchers divided the layers into two main sections – a younger layer dating to between 16,600 and 12,200 years ago, which contained about 88% of the stone tools, and an older layer that was about 16,600 to 33,000 years old, which held about 12% of the stone tools.

Ardelean noted that the stone tools show clear signs of human sculpting, including signs that ancient humans hit one type of rock with another to make a sharp, pointed edge, known as a flake.  

“You can also see repeated blows on the same spot from different angles when it was harder for them to separate the flakes and they are trying again and again,” Ardelean told Live Science. 

However, a hunt for genetic material in the cave yielded only plant and animal DNA (including junipers, firs and pines, bats, bears, voles, deer mice and marmots), but not human DNA. 

The tools were of a style never seen before by archaeologists, but this style didn’t change much over the thousands of years. Also, there weren’t many tools given how long the cave was used, so it appears that the cave was used sparsely, he said.

More evidence of human activity may lie closer to the entrance of the cave, but that area would be challenging to excavate because of the collapsed entrance, he said. 

In addition, the team found evidence of sulfur, potassium and zinc, elements that could be signs of human activities, such as butchering animals or urination, although it’s also possible that these elements were left by carnivores using the cave, Ardelean said.

Chiquihuite Cave is one of the few analyzed sites indicating that humans lived in North America before the beginning of the LGM, said Justin Tackney, an associate researcher in the Department of Anthropology at the  University of Kansas, who was not involved in the study.

“If the authors are correct, Chiquihuite Cave would represent a very significant discovery in our field,” because the site was used up to about 30,000 years ago, Tackney told Live Science.

“This would then lead to questions of which physical routes would these humans have taken to get that far south at such an early date, particularly during the maximal extent of the ice sheets.”

These dates are so early, “the focus now will be on the veracity of those few older lithic artifacts,” Tackney said.

However, the analysis of all of these stone tools shows that the humans who used the cave were flexible enough to deal with the elements so high above sea level, Harcourt-Smith said.

What’s more, “it shows that Mexico is an important region to be focusing on in relation to understanding the earliest humans in the Americas,” Harcourt-Smith told Live Science.

Palaeontologists unearth fossil from the day dinosaurs wiped out by asteroid 66 million years ago

Scientists now know that a massive Yucatan asteroid struck the earth 66 million years ago at the end of the Cretaceous Period, ultimately causing most species of dinosaur to go extinct.

It was the sudden change in climate that accompanied this disastrous astronomical collision that made the earth unlivable for these cold-blooded reptiles, leading to the complete disappearance of creatures that had roamed the earth for more than 100 million years.

But there were some dinosaurs who didn’t meet their demise as a result of catastrophic post-asteroid climate change. These dinosaurs lived in what are now known as the Americas, within the range of the impact zone of the Chicxulub strike, which occurred in the Gulf of Mexico just off the northern coast of the Yucatan Peninsula.

These hapless creatures would have been destroyed immediately or soon after the earth-shattering Yucatan asteroid impact, unable to withstand the unimaginably destructive forces unleased in the wake of this planet-killing calamity.

Now, for the first time, paleontologists have uncovered fossilized remains from one of these dinosaurs, an animal killed by the direct physical effects of the Yucatan asteroid, the single most destructive event in the earth’s history.

Skin-covered Dino Leg Severed by Yucatan Asteroid Blast!

While excavating at the Tanis fossil site in the state of North Dakota, in what is known as the Hell Creek Formation, a team of explorers working under the direction of University of Manchester paleontologist Robert DePalma uncovered the fossilized leg of a Thescelosaurus, a small lizard-like herbivore from the late Cretaceous Period .

Amazingly, the leg was intact and still covered by fossilized skin, suggesting that whatever force had removed the leg had been incredibly powerful and concentrated.

“This looks like an animal whose leg has simply been ripped off really quickly,” Professor Paul Barrett of the Natural History Museum in London, told the BBC.

“There’s no evidence on the leg of disease, there are no obvious pathologies, there’s no trace of the leg being scavenged, such as bite marks or bits of it that are missing.”  

The Hell Creek Formation , and the Tanis fossil site it contains, were created in the aftermath of the Chicxulub asteroid strike , 66 million years ago.

The Yucatan asteroid created an impact creator that was 93 miles (150 kilometers) wide, and its collision with the earth sent out echoes of mass destruction radiating in every direction from ground zero.

North America was hit by seismic waves equivalent to those generated in a magnitude 11 earthquake, and soon after by inland waves that were as powerful as those created by the most destructive tsunami. 

The Thescelosaurus was apparently killed in a sudden and exceedingly violent fashion, even though the asteroid’s point of impact was approximately 1,900 miles (3,000 kilometers) away.

Putting all the pieces together, it seems clear that the Thescelosaurus was an early and immediate victim of the Yucatan asteroid impact event, which ultimately killed off not only the dinosaurs but up to 75 percent of the animal species living on the planet at that time.

The discovery of the severed dinosaur leg is groundbreaking, paleontologists say, because no other dinosaur fossil has ever been linked directly to the most catastrophic event in earth’s history.

“This is the most incredible thing that we could possibly imagine here, the best case scenario, the one thing that we always wanted to find in this site and here we’ve got it,” Robert DePalma told the BBC .

“Here we’ve got a creature that was buried on the day of impact—we didn’t know at that point yet if it had died during the impact but now it looks like it probably did.”

The paleontologists have been able to reconstruct what happened at Hells Creek Formation after the Yucatan asteroid hit. Following the asteroid strike, rising sea levels and tsunamis would have created an inland sea to the north.

The process that created this sea also would have spawned at least two massive, towering waves that moved so far inland that they actually reached what are now the lands of North Dakota. These enormous waves washed over the Tanis site, and eventually covered the animals that died there with up to six feet (1.8 meters) of sediment.

Between the first and second of these waves, glass beads called tektites would have been raining down from the sky like tiny ballistic missiles, reaching speeds in excess of 200 miles (320 kilometers) per hour.

It is possible one of these tiny but deadly glass pieces struck the ill-fated Thescelosaurus with enough force to slice off its leg and kill it, although this is just one possible explanation for the creature’s death.

Tellingly, the sediment layer at the Tanis site eventually turned into a type of clay rich in iridium. This substance is rare on earth, but asteroids and meteors have it in abundance.

The Dinosaurs’ Final Day, Revealed in Terrifying Detail

The amazing story of the Tanis site will be introduced to the British public on April 15, when BBC One will broadcast a new documentary entitled “Dinosaurs: The Final Day with David Attenborough.”

The documentary was filmed over the course of three years, and as its narrative unfolds Sir David Attenborough will introduce viewers to many of the fossil finds that have been unearthed at Hell Creek Formation since the site was discovered in 2008.

“We’ve got so many details with this site that tell us what happened moment by moment, it’s almost like watching it play out in the movies,” DePalma explained. “You look at the rock column, you look at the fossils there, and it brings you back to that day .”

DePalma and the other paleontologists involved in the research at the Tanis site have yet to submit their latest findings for peer review and publishing. Nevertheless, they chose to reveal what they’d discovered now, to help generate more interest in the upcoming documentary.