Posted on 11/17/2003 4:02:54 PM PST by blam
Ancient hearth tests carbon dating
Bob Beale
ABC Science Online
Monday, 17 November 2003
Rock art at Serra da Capivara National Park, home of the Pedra Furada site in Brazil (Embassy of Brazil, London)
People were keeping warm by a fire in a rock shelter at least 56,000 years ago, according to new analysis of what may be the oldest known human record in the Americas.
This is about 40,000 years earlier than generally agreed for when people first arrived in the Americas.
The international team of researchers dated charcoal from a hearth at the controversial Pedra Furada archaeological site in Brazil and reported its findings in the latest issue of the journal Quaternary Science Reviews.
They used a new technique that pushes back the so-called radiocarbon dating barrier, according to Dr Guaciara dos Santos and colleagues who ran tests at the Australian National University.
Scientists have been polarised about the age of the Pedra Furada site because estimates have been in "profound disagreement" with accepted wisdom about who, when, where and how people first arrived in the Americas. These were supposedly the Clovis people who walked from Siberia into North America across an Ice Age land bridge only 12,000 to 14,000 years ago.
"These dates are good and reliable and there's no reason to doubt them," Dr Michael Bird, a member of the team who developed the new dating technique, told ABC Science Online. "The question goes back to the archaeology. If they are hearths, they are very old indeed."
The site at Pedra Furada, in the Serra da Capivara National Park, is a rich archaeological area of sandstone rock shelters. It contains many prehistoric sites, including hundreds of rock artworks, stone tools and human remains.
Earlier tests on charcoal from the deepest layers of the excavations suggested that it was at least 40,000 years old, the traditionally accepted accurate "barrier" limit of radiocarbon dating. But scientists were still puzzled about the authenticity of the hearths as human artefacts and whether younger carbon sources could have contaminated the samples and skewed the results.
The new study says that thermoluminscence testing of the hearthstones showed that they "were heated independently from the stones found outside the hearths in the same layer; thus, refuting the possibility that the stones were heated by natural fires".
It revises the dates on those earlier charcoal tests using Bird's technique to decontaminate it first. The procedure is known as ABOX (acid-base-wet-oxidation) and involves chemically scouring a fine layer off the charcoal surface.
"[This] reliably removes contamination from charcoal and wood enabling credible radiocarbon dating to about 55,000 years before present," the report said.
Bird said the method had been used in the past two years to secure radiocarbon dates older than 40,000 years for archaeological sites in South Africa and Australia, notably the famous Devil's Lair site in Western Australia, which was redated at up to 50,000 years old.
Radiocarbon dates become progressively less reliable on older material and until the ABOX technique was developed, few scientists would accept their accuracy beyond the barrier limit, he said.
"At 50,000 years you have only about 0.1% of the original radiocarbon present, so contamination with younger material is a major issue," Bird said. "This is a much better way of pre-treating the samples to get rid of any contamination. It's becoming the gold standard in archaeology for getting good reliable dates that you can believe, particularly at these old time scales."
Out of seven Pedra Furada charcoal samples scientists took from the hearth structures in the deepest layers, five were beyond the limit of the ABOX technique itself, returning ages greater than 56,000 years, the report said. Analysis of the final two samples gave finite ages of 53,000 and 55,000 years.
I don't believe that the South American Indians have diverged from their Mongolian ancestors sufficiently to account for 50,000+ years of seperation, but that's pure speculation on my part.
Not only is the carbon dating getting older and older but the evolutionists are getting bolder and bolder and further and further from the only accurate dating, the Bible.
I believe that God's account of creation is the only truth that is acceptable, and He said the way it is, only once, and His creation statements are final.
Save your breath and your flames of denial because they would just be wasted on this believer.
It's a record if it is written or drafted. It should also be recorded at the local recorder's office, although that office may be long gone. Otherwise it is a fact or possibly information, and it is probably data, too. The date is about the same as the date of earliest Australia, so what is going on here?
Though there were people there that long ago, nothing says they had to be the genetic ancestors of the current inhabitants
Well, if you're fighting "U.S. imperialism" (a communist codeword, BTW), then you can come up with all sorts of crackpot findings to support your noble fight against the Yankees. If there's one thing I hate, it's the politicization of science.
Early waves of humans going everywhere.
I posted an article about a week ago about the 1.8 million year old human skeletons found in the country of Georgia, they aren't suppose to be there....and then we still have the 200K yo Calico site in California too.
BTW, did you read the statement by the scientist about how her findings are a blow to "U.S. imperialism"? Kind of makes you wonder about her scientific detachment, not to mention integrity.
You must be from the Red Paint People, nice to meet you.
All skeletons found anywhere in the Americas that are older than 6,000 years old, are not Native Americans/American Indians as we know them today. Prior to 6,000 years ago there were other people here. There has been a slow drift/change in the language. If you'll notice the term Paleo-Americans and Paleo-Indians make a break at about 6,000 years ago.
We are related. Distantly, of course, since I am more Pigrim than anything else.
When you look at the distribution of remnant cultures, Bushmen for example, at present and then look at their historical distribution it seemes that they have been pushed to their present locations by people entering Africa not leaving, the same could be said of other remnants in other parts of the world.
I have always found it curious that things evolved in Africa and then left, it seems to me that the evidence points to things entering in waves.
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