Clovis DNA Points to Native-American Origins

The genetic sequence from a prehistoric baby in a 12,000-year-old Clovis burial site in Montana is providing significant data on the origins of the earliest Americans. Until now, archaeologists have had to rely mainly on tools made of stone and bone, and other artifacts to tell the story of human migration about 15,000 years ago to the New World.

Now that story is bolstered with some dramatic, ancient DNA, extracted from the remains of a 1-year-old boy who died in what is now Montana more than 12,000 years ago, according to a study described in Nature magazine.

"Clovis is what we like to refer to as an 'archaeological complex,' " says Michael Waters, an archaeologist at Texas A&M University.

That complex is defined by characteristic tools, he says.  

The Clovis artifacts were common for about 400 years, starting about 13,000 years ago. But at this point, there is only one set of human remains associated with those sorts of tools: that of the baby from Montana. "So this genetic study actually provides us with a look at who these people were," Waters says.

The most obvious conclusion from the study is that the Clovis people who lived on the Anzick site in Montana were genetically very much like Native Americans throughout the Western Hemisphere.

Image: Depiction of Clovis people, Mastodon State Park, Missouri

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Clovis Comet Lacks Evidence

A group of scientists from archaeology to crystallography and physics are disputing the long-held theory that a comet crashing into the Earth some 13,000 years ago spelled doom to a group of early North American people and ice-age beasts in the region.

The prehistoric Paleo-Indian group known as the Clovis culture suffered its demise at the same time the region underwent significant climate cooling known as the Younger Dryas.

"Despite more than four years of trying by many qualified researchers, no unambiguous evidence has been found [of such an event]," Mark Boslough, a physicist at Sandia National Laboratories in New Mexico, tells LiveScience. "That lack of evidence is therefore evidence of absence."

According to LiveScience:

In 2007, a team of scientists led by Richard Firestone of the Lawrence Berkeley National Laboratory in California suggested these changes were the result of a collision or explosion of an enormous comet or asteroid. 

The theory has remained controversial, with no sign of a crater that would have resulted from such an impact. 

"If a four-kilometer [2.5-mile] comet had broken up over North America only 12.9 thousand years ago, it is certain that it would have left an unambiguous impact crater or craters, as well as unambiguous shocked materials," Boslough said. 

A large rock plunging into the Earth's atmosphere may detonate in the air without coming into contact with the ground. Such an explosion occurred in Siberia in the early 20th century; the explosive energy of the so-called Tunguska event was more than 1,000 times more powerful than the atomic bomb dropped on Hiroshima.

Boslough said the math doesn't add up. The object responsible for the Tunguska event was very small, about 130 to 160 feet (40 to 50 meters) wide. The proposed North American space rock linked with the Clovis demise is estimated to have been closer to 2.5 miles (4 kilometers) across. "The physics doesn't support the idea of something that big exploding in the air," he said.

Click here for the article.

First Americans? Once Again a Mystery

A leading theory on when and how humans first arrived in North America has pretty much been discarded. The so-called “Clovis” theory was deemed credible until the last five years, when more indications have surfaced that humans were here earlier than Clovis postulated.

According to the New York Times:

For many decades, archaeologists have agreed on an explanation known as the Clovis model. The theory holds that about 13,500 years ago, bands of big-game hunters in Asia followed their prey across an exposed ribbon of land linking Siberia and Alaska and found themselves on a vast, unexplored continent. The route back was later blocked by rising sea levels that swamped the land bridge. Those pioneers were the first Americans. 

The theory is based largely on the discovery in 1929 of distinctive stone tools, including sophisticated spear points, near Clovis, N.M. The same kinds of spear points were later identified at sites across North America. After radiocarbon dating was developed in 1949, scholars found that the age of these “Clovis sites” coincided with the appearance at the end of the last ice age of an ice-free corridor of tundra leading down from what is now Alberta and British Columbia to the American Midwest.

 Disproving a long-standing theory does not automatically replace it with another, which is the current situation, as summed up in this article by Andrew Curry, a contributing editor for Archaeology magazine.

 Click here for the article.

Painting by Charles Valsechi

Clovis Killer-Comet Theory Now Deemed Impossible

A tenacious theory that explained the disappearance of the Clovis people ~ arguably North America’s first humans ~ is being strongly disputed by scientists who say it’s impossible.

The hypothesis is that a speeding comet nearly 13,000 years ago was the culprit, spraying ice and rocks across the continent, killing the Clovis people and the mammoths they fed on, and plunging the region into a deep chill. 

Now a host of scientific authorities are making the case that the comet theory is “bogus.” Researchers from multiple scientific fields are calling the theory one of the most misguided ideas in the history of modern archaeology, which begs for an independent review so an accurate record is reflected in the literature.

“It is an impossible scenario,” says Mark Boslough, a physicist at Sandia Laboratory in Albuquerque, N.M., where he taps the world’s fastest computers for nuclear bomb experiments to study such impacts. His computations show the debris from such a comet couldn’t cover the proposed impact field. In March, a “requiem” for the theory even was published by a group that included leading specialists from archaeology to botany.

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More Evidence of Pre-Clovis American Settlement

Examples of Clovis-era tools.

Thousands of 15,500-year-old stone tools unearthed over the past several years prove that the Clovis culture was not the first human population in the Americas, according to archaeologists writing in a recent issue of Science magazine.

According to the BBC:

A number of digs across the Americas in recent decades had already hinted that the "Clovis first" model was in serious trouble. But the huge collection of well-dated tools excavated from a creek bed 60km (40 miles) northwest of Austin (Texas) mean the theory is now dead, argue the Science authors. 

"This is almost like a baseball bat to the side of the head of the archaeological community to wake up and say, 'Hey, there are pre-Clovis people here, that we have to stop quibbling and we need to develop a new model for peopling of the Americas'," Michael Waters, a Texas A&M University anthropologist, told reporters.

Hunter-gatherers were thought to have crossed from Siberia into Alaska via a land bridge that became exposed when sea levels dropped. Evidence indicates this occurred as far back as about 13,500 years. But an increasing number of archaeologists have argued there was likely to have been an earlier occupation based on the stone tools that began turning up at dig sites with claimed dates of more than 15,000 years.

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New Report Dispels Clovis Comet-Destruction Theory

There simply is no evidence that a comet created a cataclysm that wiped out the Clovis people, the earliest known culture in North America, according to two archaeologists who have studied the situation.

Archaeologists David Meltzer of Southern Methodist University and Vance Holliday of the University of Arizona argue that there is nothing in the archaeological record to suggest an abrupt collapse of Clovis populations.

“Whether or not the proposed extraterrestrial impact occurred is a matter for empirical testing in the geological record,” they write in the October issued of Current Anthropology magazine. “In so far as concerns the archaeological record, an extraterrestrial impact is an unnecessary solution for an archaeological problem that does not exist.”

According to PhysOrg.com:

The comet theory first emerged in 2007 when a team of scientists announced evidence of a large extraterrestrial impact that occurred about 12,900 years ago. The impact was said to have caused a sudden cooling of the North American climate, killing off mammoths and other megafauna.

It could also explain the apparent disappearance of the Clovis people, whose characteristic spear points vanish from the archaeological record shortly after the supposed impact. As evidence for the rapid Clovis depopulation, comet theorists point out that very few Clovis archaeological sites show evidence of human occupation after the Clovis. 

At the few sites that do, Clovis and post-Clovis artifacts are separated by archaeologically sterile layers of sediments, indicating a time gap between the civilizations. In fact, comet theorists argue, there seems to be a dead zone in the human archaeological record in North America beginning with the comet impact and lasting about 500 years.

But Meltzer and Holliday argue that a lack of later human occupation at Clovis sites is no reason to assume a population collapse. “Single-occupation Paleoindian sites ~ Clovis or post-Clovis ~ are the norm,” Holliday said. That's because many Paleoindian sites are hunting kill sites, and it would be highly unlikely for kills to be made repeatedly in the exact same spot.

Click here for the complete article.

More discussion of the issue on Anthropology.net blog.

Aborigines May Have Been First to Settle Americas

Australian Aborigines on Botany Bay by Arthur Phillip, 1790.

Scientists now say there is compelling evidence that two different populations first colonized the Americas, the earliest being Australian Aborigines over 11,000 years ago.

Cranial features distinctive to Australian Aborigines are present in hundreds of skulls uncovered in Central and South America, according to evolutionary biologist Walter Neves of the University of São Paulo.

The second population to arrive ~ up to now regarded as the first migration to the Americas ~ was humans of East and North Asian origin who entered the Americas from Siberia across the Bering Strait and founded modern Native American populations, he argues. It has been believed that these Asian people spread steadily southward to eventually populate Central and South America as well.

“The results suggest a clear biological affinity between the early South Americans and the South Pacific population,” Neves says. “This association allowed for the conclusion that the Americas were occupied before the spreading of the classical Mongoloid morphology in Asia.”

According to Cosmos magazine:

Until about a decade ago, the dominant theory in American archaeology circles was that the 'Clovis people' ~ whose culture is defined by the stone tools they used to kill megafauna such as mammoths ~ was the first population to arrive in the Americas. 

They were thought to have crossed the Bering Strait from Siberia into Alaska at the end of the last Ice Age, some 10,000 or so years ago, following herds of megafauna across a land bridge created as water was locked up in glaciers and ice sheets.

But in the late 1990s, Neves and his colleagues re-examined a female skeleton that had been excavated in the 1970s in an extensive cave system in Central Brazil known as Lapa Vermelha. Dubbed Luzia, the skeleton is between 11,000 and 11,400 years old. “We believe she is the oldest skeleton in the Americas,” Neves said.

Click here for the complete article.

More Evidence of North American Cataclysm

A University of Oregon-led research team has discovered the strongest evidence yet for a controversial cosmic event occurring 12,900 years ago that tore through North America and extinguished many species.

In a paper appearing online ahead of regular publication in the Proceedings of the National Academy of Sciences, University of Oregon archaeologist Douglas J. Kennett and colleagues from nine institutions and three private research companies report the presence of shock-synthesized hexagonal diamonds in 12,900-year-old sediments on the Northern Channel Islands off the southern California coast.

These tiny diamonds and diamond clusters were buried deeply below four meters of sediment. They date to the end of Clovis -- a Paleoindian culture long thought to be North America's first human inhabitants. The nano-sized diamonds were pulled from Arlington Canyon on the island of Santa Rosa that had once been joined with three other Northern Channel Islands in a landmass known as Santarosae.

"The type of diamond we have found ~ lonsdaleite ~ is a shock-synthesized mineral defined by its hexagonal crystalline structure. It forms under very high temperatures and pressures consistent with a cosmic impact," Kennett said. "These diamonds have only been found thus far in meteorites and impact craters on Earth and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis]."

"This site, this layer with hexagonal diamonds, is also associated with other types of diamonds and with dramatic environmental changes and wildfires," said James P. Kennett, paleoceanographer and professor emeritus in the Department of Earth Science at the University of California, Santa Barbara.

"There was a major event 12,900 years ago," he said. "It is hard to explain this assemblage of materials without a cosmic impact event and associated extensive wildfires. This hypothesis fits with the abrupt cooling of the atmosphere as shown in the record of ocean drilling of the Santa Barbara Channel. The cooling resulted when dust from the high-pressure, high-temperature, multiple impacts was lofted into the atmosphere, causing a dramatic drop in solar radiation."

Click here for the University of Oregon article.

Diamond Dust Points to Comet Cataclysm

Diamond dust dating to 12,900 years ago exists at six North American sites, pointing to Earth's impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, reports a nine-member scientific team.

Nanodiamonds ~ produced under high-temperature, high-pressure conditions created by cosmic impacts and have been found in meteorites ~ are concentrated in similarly aged sediments at sites in Arizona, Oklahoma, Michigan, South Carolina and at two additional sites in Canada.

According to ScienceDaily, last year a team of scientists proposed that a cosmic impact event ~ possibly multiple airbursts of comets ~ set off a 1,300-year-long cold spell known as the Younger Dryas and led to the extinction of a large range of animals, including mammoths, across North America.

Now, reporting in today’s issue of the journal Science, a team led by the University of Oregon's Douglas J. Kennett, a member of the original research team, report finding billions of nanometer-sized diamonds concentrated in sediments ~ weighing from about 10 to 2,700 parts per billion ~ in the six locations during digs funded by the National Science Foundation.

"The nanodiamonds that we found at all six locations exist only in sediments associated with the Younger Dryas Boundary layers, not above it or below it," Kennett, a UO archaeologist, told ScienceDaily. "These discoveries provide strong evidence for a cosmic impact event at approximately 12,900 years ago that would have had enormous environmental consequences for plants, animals and humans across North America."

Click here for the complete ScienceDaily article.

Click here for today's Washington Post article.

More Details on Paisley Cave Discovery

University of Oregon archaeologist Dennis Jenkins hands a heat-measuring device to a fellow excavator at the Paisley Caves.

The Associated Press has updated an earlier news report that I posted on Ancient Tides in June regarding the discovery in Paisley, Oregon, of ancient human feces with viable DNA. The discovery has enabled scientist to pinpoint the existence of humans in North America some 14,300 years ago. That’s 1,000 years earlier than the Clovis people, earlier thought to be the continent’s first humans.

Click here for the detailed article.