New Evidence Supports Controversial Claim of Humans in The Americas 130,000 Years Ago

 Three years ago, a team of archaeologists within u.  s. proposed a rare idea: the primary human settlers within the Americas received least 100,000 years previous we thought.

The evidence came from a set of mastodon bones and ancient stones dating back to around 130,000 years ago, which perceived to are hammered and scraped by early humans. 

The remains were found within the suburbs of the point of entry within the 1990s, and therefore the researchers think that the nearby stones may are used as hammers and anvils to figure on the bones. But outside of that, no other traces of human action were found.

Today, the Cerutti Mastodon (CM) site remains one of the foremost controversial archaeological digs within the world. For years, scientists are going back and forth over the results and whether or not they indicate the presence of humans in North America 130,000 years ago, but the first authors aren't let go. 

The team has now published a follow-up paper that claims to possess found traces of ancient mastodon bones on the upward-facing sides of two cobblestones collected from the location. 

According to the paper, mastodon bones were indeed placed on top of those rocky 'anvils' and struck with some variety of hammers - presumably by humans.

If the bones were merely in passive contact with the rocks, you'd expect to determine their influence everywhere they were touching, not just the highest part. 

There also doesn't appear to be any modern contamination, the authors add. the traditional artifacts were found near a road work site, so some critics think the bones were broken and scraped by the activity of trucks and other similar disturbances.

While this can be much possible, researchers say it doesn't explain the residue on the stones.

When collecting bones and stones from the positioning, the team in the urban center claims to own taken care. they are saying there was no opportunity for bone material to disintegrate or "float" into the air and onto a stone at the initial site or within the lab afterward.

Even within the soil, bone residues from these mastodons were discovered at much lower concentrations than what was measured on some parts of the cobblestones.

"Fossil bone residues documented with the Raman microscope were only found in residue extractions sampled from the doubtless used surfaces and are therefore considered to be more likely use-related," the authors write.

"As our investigations have indicated that the bone residues are less likely to originate from sediments or contact with bones within the bone bed as discussed above, the foremost parsimonious explanation is that the residues (and wear) derive from deliberate contact with bone. We consider this scenario to be the foremost likely." 

Still, there's one key missing ingredient: collagen. this can be a very important part of mammal bones, and if stones were wont to break apart the mastodon skeleton, you'd expect to search out some traces of collagen.

It's very possible that the collagen during this case had already disintegrated from the passing of your time. Or it might be that measurements simply didn't acquire its presence.

But archaeologist Gary Haynes, who wasn't involved in the study, told Science News he thinks the more likely scenario is that road work vehicles buried these stones next to the mastodon bones, long after their collagen had disappeared.

He's not the sole one who's skeptical. Today, most evidence suggests human settlers arrived within the Americas roughly 14,000 to 20,000 years ago. A date of 130,000 years is kind of the claim, and it requires extraordinary evidence, which some scientists argue is lacking.

A rebuttal to the initial 2017 paper argued that other processes outside of human hammering produced the bone damage, especially from heavy construction equipment.

Even before humans came along there was probably disturbance within the area. Over time, as fluvial deposits slowly covered the remains, these mastodon bones would have remained somewhat flexible, and this implies they might are trampled, displaced, fractured, abraded, and reoriented by other mammals that used the traditional muddy watercourse.

"The extraordinary claim by Holen et al. of prehistoric hominin involvement at the CM site shouldn't be dependant on evidence that's receptive multiple, contrasting interpretations," the authors of the rebuttal argue.

"Until unambiguous evidence of hominin activities is presented, like formal stone tools or an abundance of percussion pits, caution requires us to line aside from the claims of Holen et al. of prehistoric hominin activities at the CM site."

Shortly afterward, the first authors wrote a rebuttal to the rebuttal. In it, they argued that there's no evidence of fluvial deposits in which the bones were broken before they were buried and not trampled afterward.

"Healthy skepticism is that the foundation of excellent science, and also the publication of this discovery is that the beginning of a scientific debate, which I welcome and encourage,"  Tom Deméré, a paleontologist at the port of entry explanation Museum and one in all the initial authors, argued some years ago.

"What I didn't expect was the reluctance of scientists to have interaction in a very two-way conversation to objectively evaluate our hypothesis." 

Archaeologist David Meltzer from Southern Methodist University is skeptical but receptive the controversy. He says he can be convinced that humans arrived within the Americas a 100,000 years previous we thought, but that he hasn't seen enough evidence yet. 

"Given everything we all know, it makes no sense," he told Nature in 2018. "You're not visiting flip people's opinion 180 degrees unless you have absolutely unimpeachable evidence, and this ain't it."

Perhaps this new bout of evidence will help clear up a number of that doubt. More likely than not, however, it'll merely trigger a series of latest rebuttals.