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Saturday, May 26, 2012

Native American Origins

Challenges to a Long-held
Archaeological Assumption


From a fascinating article in the New York Times, archaeologists are beginning to challenge some of the traditionally accepted explanations for the origins of Homo Sapiens in the Americas:
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.

[...]

Over the years, hints surfaced that people might have been in the Americas earlier than the Clovis sites suggest, but the evidence was never solid enough to dislodge the consensus view. In the past five years, however, a number of discoveries have posed major challenges to the Clovis model. Taken together, they are turning our understanding of American prehistory on its head.

The first evidence to raise significant questions about the Clovis model emerged in the late 1970s, when the anthropologist Tom Dillehay came across a prehistoric campsite in southern Chile called Monte Verde. Radiocarbon dating of the site suggested that the first campfires were lighted there, all the way at the southern tip of South America, well before the first Clovis tools were made. Still, Professor Dillehay’s evidence wasn’t enough to persuade scholars to abandon the Clovis model.

But in 2008, that began to change. That year, researchers from the University of Oregon and the University of Copenhagen recovered human DNA from coprolites — preserved human feces — found in a dry cave in eastern Oregon. The coprolites had been deposited 14,000 years ago, suggesting that Professor Dillehay and others may have been right to place humans in the Americas before the Clovis people.

The Clovis model suffered yet another blow last year when Professor Waters announced finding dozens of stone tools along a Texas creekbed. After using a technique that measures the last time the dirt around the stones was exposed to light, Professor Waters concluded, in a paper in Science, that the site was at least 15,000 years old — which would make it the earliest reliably dated site in the Americas.
These remarkable archaeological discoveries are only augmented by the fact that genetic markers in the DNA of modern American Indians and their predominantly Asian forefathers reveal that both shared a common ancestor that lived more than 16,000 years ago, more than 3,000 years before the traditional Clovis land bridge hypothesis. 

So where does this leave us?  It is difficult to say.  There is still much about the Clovis model that is desirable to archaeologists.  With that said, it is crystal clear that we are far from certain when it comes to explaining the ultimate origins of Native American people.  The most likely explanation is that scores of people from all over the world (with Asian colonizers being the obvious dominant party) made their way to the Americas over a very long period of time, much longer and older than we previously have believed.  What is very clear is that these early colonizers were fully developed Homo Sapiens, predominantly from Asia, who made their way to the American continent in a variety of ways.  But, in the end, nobody can say for sure, and these new discoveries actually give us more questions than answers; questions that we will probably never have full answers to either.  Archaeology, particularly ancient American archaeology, has a lot of hurdles to overcome.

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