Further analysis of the earliest group of tools—and the techniques used to make them—showed a strong similarity to known tools from that time period in East Africa. The presence of two techniques, Levallois flaking and bifacial reduction—which in the outer chunks of a rock are flaked off to separate a useable core—underscore the makers' African origins. "In East Africa and northeast[ern] Africa bifacial reduction is a constant part of the technological repertoire of people," Marks said. "In Africa they produce hand axes, but also what are called foliates—leaf-shaped bifacial pieces," he added, noting that "either you have a connection to East Africa or you have an independent invention of this technique from a group that has no history in the area."
And the later layers of tools, groups A and B, did not bear evidence of the use of these techniques. "These marked differences led us to conclude that assemblages A and B developed locally and in basic isolation," Marks noted.
Even though the tools were not accompanied by any direct H. sapiens fossil evidence, the research team is confident that they were not made by another more primitive human relative, such as Neandertals. "There's no evidence for any Neandertals south of that [Russian-Asian] temperate zone to the east," Marks said. Certainly another group cannot be ruled out but, he noted, that would have meant that an errant group of Neandertals "took a turn south, went several thousand kilometers into what at the time was desert," he said. "It seems to me a very difficult explanation and one that doesn't follow any reasonable logic."
Not everyone in the archeology field, however, is convinced that the stone tools in the C grouping have an undeniable connection to Africa. "I think the verdict here is ambiguous," says John Shea of Stony Brook University's Department of Anthropology, who was not involved in the research but is familiar with the paper. Given that all H. sapiens originated in Africa, he adds, "it is likely that either [the tools'] makers or their makers' ancestors came from Africa"—but not necessarily directly. "When the Earth offers up what you have long been seeking," he adds, "a good archaeologist needs to be on guard."
Marking the time of sands
Because the evidence for human occupation at the Jebel Faya is not biologically based—from bone or other animal or plant material—the samples could not be radiocarbon dated (aside from some shells that turned up in an overlaying layer, which were dated at some 9,700 to 10,400 years ago). The research team thus had to find a different means to date the tools. "Archaeology without ages is like a jigsaw with the interlocking edges removed," Simon Armitage, of Royal Holloway, University of London, and co-author of the paper, said on Wednesday. "You have lots of individual interesting pieces of archaeological information, but you can't fit them together to produce the big picture."
He used single-grain optically stimulated luminescence (OSL) dating to determine how long the surrounding sand grains had been buried. "When a sand grain is buried it's exposed to very low levels of naturally occurring radiation from the surrounding sediments," Armitage explained. The radiation separates electrons from their host atoms and entraps them in a different part of the crystal. Once exposed to sunlight again, the electrons are freed, "and in doing so, they emit a tiny amount of light called luminescence," Armitage said, likening the process to discharging a rechargeable battery. If collected without being exposed to sunlight, the sand grains' luminescence can be measured with OSL dating, revealing the time that has passed since it was last buried.
Many of the recent brushstrokes of human migration have been painted not with sand grains, but rather with the help of DNA analysis. Sampling of genetic material from people around the world has put the first major human exodus out of Africa at some 60,000 years ago. But as defenders of rock-hard stone evidence, researchers behind the new paper stand behind the accuracy of their findings. "Genetics can only tell us which event happened before another or after another, and the estimates of time are very rough," Uerpmann said. He said he was not surprised that their results contradicted DNA estimates and suggested that it will "stimulate thinking" about the genetic approach.
Nevertheless, the researchers acknowledge that fragmentary artifact-based evidence is not perfect for following early human dispersal around the globe. "To track them archaeologically would be extremely difficult," Marks said. "What we have been able to do here is a first step."
The findings in the U.A.E. do not preclude the Nile route out of Africa from being taken as well. "Our findings open a second way," Uerpmann said, adding that in his opinion the Arabia route "is more plausible for massive movements than the northern route."
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Add CommentAs I understand, fossilization most often occurs in very specific conditions - usually, I think, flowing water repeatedly overlaying a carcass with sediments. If so, environments that do not contain these conditions may not produce any fossils, regardless of any species populations that may exist there.
Reply | Report Abuse | Link to thisIn this case, fossil finds do not provide any representative sampling of resident population geographical distributions, and the absence of fossil evidence does not indicate any absence of population residency.
A fascinating article that tantalises with an exciting vista of earlier human migration. But a lot more evidence will be needed to confirm if this is the case and people need to remain open minded and wait for that evidence.
Reply | Report Abuse | Link to thisWOW! I've never seen anything quite that ignorant or offensive posted here. There is only ONE species of human extant on earth now. If you don't believe me ask geneticists. No one human being is more than a fraction of one percent different than another genetically. Not only are we one species but we've got remarkably low genetic diversity for a species as numerous as we are. Written large? We're inbred as all get out. Modern human populations went through what's called a genetic bottleneck sometime in the last 80 thousand years or so. That means we nearly became extinct at some point in the relatively recent past. Every man woman and child alive today is descended from a group that was probably no larger than a couple thousand people possibly as small as 250.
Reply | Report Abuse | Link to thisThe great variety of surface variation in people is just that. Surface variation. While there are definitely some genetic distinctions from one geographical region to another and some of those distinctions are functionally important (IE specific mutations that confer resistance to parasites or the ability to digest milk into adulthood) none is sufficient to qualify any other group of humans on planet earth as a separate species. No matter how you slice it the differences are ridiculously tiny. There is more genetic variation from two different chimpanzee troops a couple miles apart in africa (Members of the same species, I might add) than there is in the entirety of humanity.
I strongly suggest you do a bit more reading... Maybe something not on a conspiracy website.
I will grant you one and only one point. Some of the differences in humans that occur regionally can be medically significant if current data are to be trusted, but again this doesn't pass muster in the big picture as a reason to define any group as being a separate species.
For the record ethical and moral people don't need a reason to avoid bigotry and racism. No justification is necessary for what is clearly ugly and wrong.
Man, the trolls come out of the woodwork on this site. Must mean SCIAM is doing a good job. The whack jobs feel threatened. Yeah I know calling them whack jobs isn't productive, but I'm having a mental health moment.
Reply | Report Abuse | Link to thisAnyway, outstanding article. :-)
Don't feed the trolls guys ......... Come on ! :)
Reply | Report Abuse | Link to thisIt is an indication of migration of a small group from Mars when Mars was alive and human beings were at the height of their civilization. Some clues may come from Mars after Russia is successful in their piloted mission to Moon.
Reply | Report Abuse | Link to thisdebu, I truly hope that was in jest. Otherwise I can't imagine why someone of your mental capacity is reading the Sci-Am website.
Reply | Report Abuse | Link to thisI agree Doug, Deb is wrong. Those artifacts are actually much older than thought. They were made by an advanced group of velociraptors, right before the big asteroid hit. Real question is, did they make it into space and survive? Think 'greys'. Note that there is no fossil evidence of H. Sapiens. Other question is: Is my theory more entertaining than Deb's? By the way, it is an interesting article.
Reply | Report Abuse | Link to thisI think this advanced group of people left some behind!
Reply | Report Abuse | Link to thisSpiff
Dispersal occurs in animal populations. Whenever a barrier can be overcome by a breeding pair or more, successful dispersal has happened.
Reply | Report Abuse | Link to thisWhat is called paleolithic includes groups of hominins that broke stone into useful tools. Paleontologists can discriminate among the techniques with which tools were made. These tools look and are described as requiring complex work.
An important point is that finders have proxy dated and found the approximate age of the tool leavers. At that time the Sahara and the Arabian deserts were quite different in climate.
It is doubtful that any significant number of preagrarian people were slaves. Expect hunters to eat meat. Hunter-gathers had to range within territories that were sufficient in size to thrive, and bringing slaves just increases mouths to feed. I leave you with a more obvious use for strangers with whom one disputes.
Significantly larger brains than our averages, were the norm until the agrarian revolution. Some theories associate larger brains with decreased disposition to subservience.
Consider that nation-states, and city-states, and their practices would be highly unlikely, as the characteristics of hunter-gatherers are individualistic relative to almost all present cultures, with bands being less than 20-30, only visiting others for short periods. The others with whom they visited were likely related, and friendly, as foot locomotion prevents breeding populations from distant travel and raiding.
Point? Commentators must look beyond their own biases.
Dominance has specific meanings in various fields of inquiry, and the pretension of dominance to which some commentators appear to adhere, is extremely temporary in a species that continually reforms coalitions in which individuals achieve social dominance.
To use resources is not dominance, but a characteristic of individuals and populations. The results of overblooming species tend to hold the seeds of their collapse.
Like other readers, I am curious as to the reasons for that population bottleneck which occurred after the period of this finding. Dispersed populations, if too thinned by a catastrophic or demographic effect, might find it hard to reconnect, and a cascade of loss occurs.
This tool in the picture, look to me like Homoerictus tools
Reply | Report Abuse | Link to thisThe tool in the picture look to me like Homoerectus tools
Reply | Report Abuse | Link to thisCan any one please tell 'why the migration along Nile is discarded and a coastal route is preferred'. Is it not a river route more vegetated and easy to get food? The earliest human being born and lived inland,is it not natural will be afraid of the vast expanse of water of the sea? Not that in this travel he had to cross long expanse of water to reach the Arabian peninsula as the sea level was very much low.
Reply | Report Abuse | Link to thisV.K.GUPTAN vkguptan@hotmail.com
I believe that most of human history is under water and once the means to study these artifacts happens the results will require rewriting the history books.It is quite possible that a number of very advanced civilizations have existed in the past 50,000 years.
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