The presence of a settlement in the middle of North America by 15,500 years ago gives "ample time for Clovis to develop" and plenty of time for people to reach the South American sites in Monte Verde, Waters said.
But such an early, glacial-period arrival poses some problems for the overland route through the Laurentide and Cordilleran ice sheets, the corridor between which would have been closed until about 15,000 years ago. "As you push it back," Bamforth says of the early settlement, "they have to come down the coast" before penetrating the continental interior. Recent descriptions of relatively sophisticated stone tools from California's Channel Islands also add strength to a costal path.
Diligent dating
Surrounding any ancient artifact is a slurry of questions and doubts as to whether the place they are found reflects when and where they were originally discarded. And when biological material is scant or absent, making radiocarbon dating impossible, scientists can face greater challenges in establishing just how old objects really are—even though, as Bamforth says, it is becoming increasingly obvious that "people have to have been here way longer than radiocarbon dating could suggest."
Nevertheless, pinning down a precise date is difficult. "Artifacts move around in the ground all the time," Bamforth said. But, he noted, the researchers behind the new work "have shown in great detail that the site is intact," adding that he was impressed with "how carefully they were able to document the age."
The team found "uniform particle size distribution" in the clay around the fragments, suggesting that it had not been disturbed when—or since—the rock pieces were dropped, Nordt explained during Wednesday's briefing.
Because the researchers did not find enough biological material in the nearby dirt to perform radiocarbon dating, they used optically stimulated luminescence (OLS), which measures the amount of radiation trapped in sediment grains when they were last exposed to sunlight. The technique is "not as precise as radiocarbon by a long shot," Bamforth says. And although early studies arrived at some pretty errant dates, the technology has been refined and now, Bamforth notes, "it really works."
But because the technology has only come into wide use in the past several years, many sites discovered and described earlier did not have the benefit of OLS dating. So if no biological material was available for handy radiocarbon dating, researchers would have had no way to gauge exactly when an assemblage of tools was made. And even the team behind the new paper, Bamforth points out, "they wouldn't have had pre-Clovis dates on this site without OLS."
The new dating development, along with the apparent lack of a hallmark tool or style means that "the possibility is that pre-Clovis is all around us, and we just can't recognize it," Waters said.
A new old Clovis?
Many of the rough, chipped chert chunks at Buttermilk Creek might look crude, especially when compared with a refined prototypical fluted Clovis spear point. But, as Waters pointed out, most Clovis sites are littered with "utilitarian chips like we found at Buttermilk Creek."
Better preserved ancient Homo sapiens, such as those found frozen, reveal that stone tools might represent little more than 5 percent of a culture's material relics. The rest, whether textiles or other more delicate artifacts, would have been destroyed by time had it not been for protective permafrost. So, Waters noted, "we have to be careful about how we interpret the evidence that we have."
Under the microscope, the researchers found that some tools had likely been used to carve hard material, such as bone or wood, and others seem to have been applied to softer surfaces, such as animal hides.
As Waters and his colleagues described in their study, the people who made these tools were already using some similar, if less exacting, techniques as the later Clovis patterns, such as bifacial points.
The rough similarities between some of these earlier tools with later, more sophisticated Clovis technologies has Bamforth pondering whether distinguishing this assemblage as "pre-Clovis" is necessary. "I wonder why it's all just not Clovis," he says. "It's not a critique of their work—it might just be a new way of thinking about it," he says, noting the distinctive "style zones" found in different ancient groups working stone in different regions.
Shea notes that it can get tricky when trying to ask these big human questions of chips of cold stone. "As to whether it is 'ancestral' to Clovis in a meaningful sense" is a knotty question, he says. Unlike genetic links among people, tools "can't have ancestor–descendant relationships with one another."
The research team is not arguing that there was a definite disconnect between these earlier Buttermilk Creek visitors and Clovis-era peoples—or for a separate settling of the continent. Rather, as Waters noted, these earlier groups would likely have eventually developed into the groups that produced the Clovis tools.
Firmer answers should emerge as other sites are discovered—and as more genetic data is gathered from ancient remains. But it is always going to be more challenging to affix firm start and end dates to the earliest settlement groups, because the older the site, the more likely it is to have been wrecked in the intervening epochs. And populations were so few and far between that they were not likely producing the sheer quantity of stone tools that were later made in the Clovis style. In order to land firmly on science's radar groups "have to cross the threshold of archaeological visibility," Bamforth says.
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26 Comments
Add Comment@Unbeliever,
Reply | Report Abuse | Link to thisYou think that rock chips left by bands of nomadic hunters is a pollution issue? Really? I shudder to think what you think of billions of tons of plastics, sewage, and smog being emitted atmosphere on a daily basis from nearly seven billion people.
Oh, I see you were erecting a hypocritical argument that no one in there right minds would make. My mistake.
to Unbeliever, the article notes that 95% of their material culture WAS biodegradable, far better than ours. Their food was 100% organic, all meat was free range. What's your opinion on their rock art, art or graffiti?
Reply | Report Abuse | Link to thisGlad to see "solid" evidence for a much earlier arrival of men and women into the Americas, and most likely along the coastline, their campsites underwater until the next ice age. The Missoula Floods would have wiped out evidence in the Columbia River Basin. Where were the most likely inland migration routes? I would assume they would have followed water and game animals, and avoided the mountain ranges and deserts. Was the San Francisco Bay Area such a Shangri-La that the people there didn't even need to do much big game hunting, with an almost 100% biodegradable culture, thus we lack evidence (or have already destroyed it)? I expect that the population there was much higher than we have evidence for, and probably dates back to the earliest arrivals. What would have been the pressure to continue migrating once people found such abundance? Expanding populations?
Gotta love the irony. In the very State where the Board of Education is pushing for the teaching of young Earth creationism alongside evolution, we find proof that people were around 9000 years earlier than what these morons believe is the age of the Earth!
Reply | Report Abuse | Link to thisThe Boy Scout in me hates a litterbug, the anthropologist loves them!
Reply | Report Abuse | Link to thisAren't they still chipping stone tools in Texas? Or is that just the politicians...?
Reply | Report Abuse | Link to thisWhat happened to the evidence that the Clovis tool precursors were developed in Europe? As I understood, Siberian based tools were completely different antler mounted stone mini-blades. It seems unlikely that Asian populations would suddenly develop sophisticated, completely unrelated Clovis points.
Reply | Report Abuse | Link to thisIf they replace the Theory of Evolution with religious nonsense in Texas public schools, there's a good chance that stone tools like this could become an important part of the economy again.
Reply | Report Abuse | Link to thisGreat and incisive article. It must seem that almost every pre-history culture would leave behind some rements of their habitation, even in the "organic" paradise that was North America. Thank God (only if appropriate)that they did. Otherwise we would have nothing to gauge their movements, migration, etc... that we investigate and question so much.
Reply | Report Abuse | Link to thisOf all the places and times one could wish for, I believe the vast unspoiled and unpolluted expanse of North America, and as sparsely populated as it apparently was, must havw been the place to be.
Apparently, or at least I believe, humans have been coming here for thousands of years; down the pacific seaboard coastline past the glaciation, over the exposed Beringia (?) land bridge and down ithe into the northern continent, perhaps even islanders from the Atlantic isles or up from Austrailia.
Perhaps someday we will learn more from burial sites and X and Y DNA tracking.
Really, other than obvious attempt at humor (he he, got it) why would anyone even mention that chipped tool remnants would be considered polution, is beyond me.
One thing that we can probably all hopefully agree on
is the fact that so, so little evidence of human habitation has been found, or perhaps "left behind", that we should be thankful for that which we do find.
Those lucky enough to have found this pristine paradise, whether by traveling here or being born into a clan or tribe already here, should indeed consider themselves lucky, however I doubt they didn't give it a thought.
Just looking at the bison and mammoth filled planes, the pristine clear night sky, with a view of the cosmos that we can only dream of, and living within a clan or tribe that lived relatively ""pollution free" should make some of us envious of that period in pre-history.
If we (mankind) ever builds a time machine (who knows?) or can take choose to take advantage of when and where we can reincarnate (to satisfy those with a spiritual influence, and why not, no one knows for sure, may as well cover all bets), then I surely know where I want to relocate, and when.
Until then, we can only hope to find those garbage dumps and burial pits that have gotten us this far.
There is obviously much, much more to be learned.
I, too, wonder why they wandered. I have a personal theory that somewhere in the mammalian genetic code is a yearning for a better world, which might be the driver for evolution and which, in humans, has led to our capacity for spirituality.
Reply | Report Abuse | Link to thisBeautiful as the pristine environment inhabited by these early humans must have been, perhaps they too had some notion of greener pastures elsewhere.
I hope science can uncover some evidence that might help explain the mystery of all these migrations, so far from home, so long ago.
I'm a fairly old dude who has been computing for over thirty years. I've read a lot of really dumb posts on different sites that had to have been written by complete morons. I have to admit that I have never read anything as blindingly asinine as your post Unbeliever. Primitive people would probably have worried about using biodegradable materials, pollution, and littering if they hadn't been so freaking busy worrying about staying alive. You are breathtakingly stupid.
Reply | Report Abuse | Link to thisWhy did they wander? Curiosity? Looking for more game? Hoping to find an easier place to live? There is some evidence that early humans were capable of reducing animal populations fairly quickly in a given area. Also remember that a population needs to move, on average, about 10 miles a year to cover 5000 miles in 500 years; not a lot of tome historically.
Reply | Report Abuse | Link to thisPersonally, I tend to think that, as we now believe that there were several migrations out of Africa, we will eventually find that there were several migration into the Americas and that not all of them originated in Asia.
Hunters & Gatherers' first priorities were undoutedly Food, Shelter and Water. Even a pristine system can only support so many at the top of a food chain. If times were good the early populations would have expanded their numbers quickly. This would have accelerated population expansion outward into the most desireable locations. Desireable locations would have once again centered around water. Rather than spread like spilled paint over everything migrations would probably have foollowed water courses and been more linear. Small groups may have traveled great distances as the terrain would permit. Watch how beavers can work a marginal area. They will move on rather quickly as they eat themselves out of house and home.
Reply | Report Abuse | Link to thisGreat article. I am sure there is more to come if we don't manage to pave over everything!
If I understand this article correctly, the author is saying that the society residing in this preClovis settlement near Austin, TX, crossed into North American using the land bridge with Asia, as did the Clovis people later. It seems to me that I have read other theories suggesting that South American tribes traveled up to North America around the same time both on land and by sea. Is that true, or am I mistaken? I have even read theories by some anthropologists that suggest early North American residents traveled here by sea from Pacific islands.See More
Reply | Report Abuse | Link to thisAnd yet there are still this European-supremacist racists saying, "so & so (a white guy) discovered this, discovered that"... that racist crap is on NPR (mainstream), in mainstream history books, in the common verbiage & it should go. People have been in the US since the last ice age; they discovered it, after the members of other species who were here first, of course.
Reply | Report Abuse | Link to thisUnbeliever was joking. Lighten up, man.
Reply | Report Abuse | Link to thisI really don't believe the "discovered" usage is meant to be "European-supremacist racist..." It's just short-hand for saying it became a part of the written historical record of our current (world-wide) culture, to which we all have access. The record we use in the US is mostly part of the European tradition. But it can be said equally that the Chinese "discovered" western Europe when they sent envoys to ancient Rome.
Reply | Report Abuse | Link to thisFor example, the Mayans, or course, knew of Mayan culture, but their records disappeared when their civilization disintegrated. So, Mayan culture was "discovered" when Europeans encountered, studied and recorded the remains. Now anyone who can read can know of Mayan culture. If the Chinese had encounted it first, made a written record, and passed that down to us, they would be considered the discoverers.
It's just a matter of perspective.
Unbeliever, you are an idiot.
Reply | Report Abuse | Link to thisDid any of the archaeologists excavate below the layer where the artifacts were found??
Reply | Report Abuse | Link to thisAs this was obviously an attractive site there may be earlier use of this site.
Unfortunately, there are some in Texas who now want to return us to those golden, halcyon times of glory.
Reply | Report Abuse | Link to thisCan we now, finally, ditch the 12,000 year arrival time? For decades it has depended on ad hoc attacks on one site after another, where site after site always proved, amazingly, to have some reason to disbelieve a pre-12Ka date. It was getting to be as contrived and ridiculous as creationism. It's been junk science for my whole career, and time to recognize it.
Reply | Report Abuse | Link to thisYou tell 'em!
Reply | Report Abuse | Link to thiswww.ncse.com
In the early 1950s for a gifted class in elementary class I was encouraged to collect artifacts at Sal Del Rey, a large HYPER saLTY lAKE IN sOUTH tEXAS FAR SOUTH OF THE HILL COUNTRY. Among the broken ceramics where the natives appaRENTLY BOILED THE WATER DOWN TO SALT FOR CENTURIES WERE BEDS OF FLINts and other stone and ivory tools. My teacher had rejected my suggestion that these salt producing fires on ceramics were from the Clovis since they were \not present in the area yet. So I brought her an artifact that looked like an antihythera mechanism as well as reports of a giant face, the size of a football field we kids played on on the beacbh of Sal del Ray, just to be told that no natives who could have created that 30 foot high bas elief sculpture had existed around there when a lot of fossilized ivory I found there couls hVE BEEN THERE BECAUSE IT WOULD HAVE TAKEN 10 k YEARS TO FOSSILIZE. aND MY TEACHER LIKEWISE WOULD NOT COME OUT THERE TO LOOK AT THE QUATER MILE LONG BOATS IN THE MIDDLE OF THE LAKE SINCE SUPPOSEDLY PEOPLE DID NOT MAKE SUCH BOATS WHEN THEY COULD HAVE GOTTEN IN THERE (BEFORE THE GIANT SALT SEA ON THE EDGE OF THE gULF HAD BEEN SEPARATED BY pADRE iSLAnds from the interior salt sea before the salt sea had evaporated over 10K further separated from the underwater ruins in the Gulf. Only years later did I find out about the world-wide flood and migrations of natives at and after 10.5 K that explained those and a multitude of other puzzsels and fossilized artifacts I had and some I haveto this day.But I could never figure out why archeologists and geologists are so reluctant to challenge well established errors that are popular even when they are clearly wrong!
Reply | Report Abuse | Link to thisMigration is certainly a characteristic remaining in some of us.
Reply | Report Abuse | Link to thisHunter-gatherers are required to migrate with abundant food, in any migratory species.
Animals evolved precisely to migrate - to find a new food source, and to leave behind that which is devoid of resource, or inimical to the reproductive life of that species.
We would be far more like the fungus, a relative closer
than plants, if we had chosen settlement early enough!
Herding humans also need to migrate, as their resource exhausted the resources it needed.
Only saturated populations settled down, occupying resource areas large enough to survive.
Clovis was a technology, perhaps traded and taught. The technology was efficient, and its results may have changed North American ecosystems on a vast scale.
During the glaciated periods, you will remember, sea levels were far lower, sometimes extending out to the continental shelf/slope boundary. So much is buried by sea, that we could expect from human habitation patterns of the knowable past and present, that most archaeological artifacts remain there.
This difficulty also exists in the Euxine lake that preceded the fast filling of the Black Sea.
In our imaginative envisioning of the North American landscape we often forget the the wolf was a highly visible part of those Serengeti-like herds of bison, antelope, caribou. It is also a highly-developed social and hunting species, able to evaluate other species and individuals, and recognize relationships. 18th and 19th century explorers have written of their aboundance.
The wolf evolved social and breeding responses to population saturation, that did not require environmental manipulation.
Native Americans and grizzly bears migrated to this continent. We are an introduced species that disrupted and changed ecosystems before the Clovis explosion.
The article mentions a gap in Clovis-related toolmaking in Siberia, to respond to a comment question. Until this discrepancy is filled there will likely be disagreement on relationship with technologies that appear related.
Sarah B: Sorry, the emmigrations were made necessary not only by the tsunami floods flinging boatloads of whalers South,across the Northern Hemisphere (after the earthquKWA PRODUCED BY THE EXPLOSION OVER THE nORTH pOLE; tHE SUBSEQUENT MIGRAQTIONS WERE MADE NECE3SSARY BY THGE FACT THAT THE TSUNAMI FLOODS WASHED AWAY MUCH OF THE FLORA AND MUCH OF THE FAUNA THE SURVIVORS HAD LIVED ON BEFORE THE TSUMANIS. tHE PEOPLE WENT INCREASINGLY FURTHER SOUTH AS THEY FOUND MORE OF THE FLORA AND FAUNA INTACT.
Reply | Report Abuse | Link to thisPlease romove the caps lock key from your keyboard and place some kind of protective barrier there so that you can't accidently hit it. You really look like an idiot when ever you use caps inappropriately. Please also provide links to reliable sources for evidence of this supposed flood. I've heard the theory before from creationists but they never has any actual proof.
Reply | Report Abuse | Link to thisI learned that the early fishermen who went far out to sea and established colonies in New Guinea, Australia, and other places thought about going along the coast of Asia and reaching America. They said to each other, "Let's leave few clues because absence of evidence is evidence of absence."
Reply | Report Abuse | Link to thisThen I learned that when the first Americans crossed from Siberia they decided they must travel north of Mt. Mckinley. Then they walked south alongside the glacier. Finally they reached the United States. Then one said to the other, "Let's fan out across the United States." The other one replied, "No! we must all head straight for Clovis, New Mexico. That is the place from which all American Indians must originate." So all the Indians went straight to Clovis and all of them originated from there. The Garden of Eden is Clovis, New Mexico.
Those Indians vanished from the face of the earth and Indians forgot how to make clovis points except of course that a some have been found in Florida stream Archaeological sites from 6,000 years ago among arrow heads. In Florida they retained the clovis point for use with spears but used a different point for an arrowhead.