Posted on 03/13/2008 2:12:58 PM PDT by blam
Americas Settled 15,000 Years Ago, Study Says
Stefan Lovgren
for National Geographic News
March 13, 2008
A consensus is emerging in the highly contentious debate over the colonization of the Americas, according to a study that says the bulk of the region wasn't settled until as late as 15,000 years ago.
Researchers analyzed both archaeological and genetic evidence from several dozen sites throughout the Americas and eastern Asia for the paper.
"In the past archaeologists haven't paid too much attention to molecular genetic evidence," said lead author Ted Goebel, an archaeologist at Texas A&M University in College Station.
"We have brought together two different fields of science, and it looks like they are coming up with the same set of answers."
The article, which is published in tomorrow's issue of the journal Science, shows that the first Americans came from a single Siberian population and ventured across the Bering land bridge connecting Asia and North America about 22,000 years ago.
The group got stuck in Alaska because of glacial ice, however, so humans probably didn't migrate down into the rest of the Americas until after 16,500 years ago, when an ice-free corridor in Canada opened up.
Clovis Not First
Scientists have long agreed that the first Americans came from northeast Asia, according to Goebel.
But the new article—which analyzed genetic and archaeological evidence from 43 sites, including a dozen sites in Asia—better pins down the makeup of the first Americans.
Genetic evidence, for instance, points to a founding population of less than 5,000 individuals.
Some geneticists had also previously suggested that the migration across the land bridge could have occurred as early as 30,000 years ago.
"Now there seems to be consensus among those studying mitochondrial DNA and [chromosome records] of modern native Americans that it happened pretty late, after the last glacial maximum, maybe as late as 15,000 calendar years ago," Goebel said.
Meanwhile, archaeologists for years had considered sites belonging to the so-called Clovis culture, which dates back 13,000 years, to represent evidence of the first Americans.
The Clovis culture was named after flint spearheads found in the 1930s at a site in Clovis, New Mexico. Clovis sites have been identified throughout the contiguous United States as well as in Mexico and Central America.
But several sites, from Wisconsin to Monte Verde in Chile, have been discovered in recent years that predate Clovis by at least a thousand years.
"There probably has to have been some time before Clovis in which people were here, but they didn't leave much of a record behind because there just weren't that many people," Goebel said.
Coastal Route
Archaeological evidence shows that there were people occupying the Asian side of the Bering land bridge area as early as 30,000 years ago.
"That tells us that once early modern humans spread out of Africa around 50,000 years ago and colonized temperate Eurasia, it wasn't very long before they had developed the technology and the skills needed to be able to make a go of it in the Arctic," Goebel said.
Modern humans spread across the land bridge about 22,000 years ago, according to the new article.
But then the group got stuck for up to 5,000 years, blocked by thick ice sheets across Canada.
It was only when the ice had melted sufficiently that humans began to spread south, either along the coast or though an interior corridor in western Canada, the authors say.
"That might have been the bottleneck that kept people from draining south from Alaska into temperate North America," said Goebel, adding that geological evidence suggests the Pacific coastal corridor would have become ice-free perhaps as early as a thousand years before the interior corridor.
"This suggests that the first Americans may have spread through the New World along a coastal route," he said.
Henry Harpending is an anthropologist and population geneticist at the University of Utah in Salt Lake City who was not involved in the study.
He agreed that there is a consensus emerging among researchers studying the first Americans.
"But there are still outstanding questions," he said.
For example, there are some "puzzling anomalies" in the Alaskan archaeological record dating back to before the glacial melt, he pointed out.
And there are several possible reasons other than ice why people did not venture south earlier, including a "ferocious army of predators" living in North America that might have had a role in keeping humans away.
"We all have open minds, and we will leave them open," Harpending said.
I bet the “natives” are getting restless about this...?
“Genetic evidence, for instance, points to a founding population of less than 5,000 individuals.”
I can trace mine back to 2 individuals.
The Schaefer mammoth, found in Wisconsin bearing cut marks suggesting it was butchered by humans, is thought by archaeologists to be about 14,500 years old.
The remains are part of a growing body of genetic and archaeological evidence suggesting that humans crossed the Bering land bridge about 22,000 years ago, then moved southward relatively late after melting ice cleared a path through Canada, a new study says.
Photograph courtesy D. Joyce
“Goebel”
Unfortunate name for a geneticist.
Damn lawyers.
I LOL’d. I hope that was a humorous post, if so I got it. If you were being series, oops... :o)
YEC INTREP
The original "illegal immigrants."
Oh, wait...
Now why would you say that?
"We all have open minds, and we will leave them open," Harpending said.
Speaking of open minds, he should remind the warming alarmists that Global Warming made settlement of the Americas possible.
When is the United States going to withdraw from the occupied territories?
This is what we keep asking Israel to do. They were attacked. We were not.
Got a kid to donate?
And vegetarianism!
Prior to agriculture, made possible by global warming, humans were hunter gatherers, with an emphasis on the hunting.
Oh yeah, about 8,500 years before the Good Lord created the Earth, right!
Or about 4.52 billion years after.
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