Scientists report they have discovered the oldest documented site of human habitation in North America, a hunting camp on an Alaskan mesa 150 miles north of the Arctic Circle.
The hunting camp, in the northern foothills of the Brooks Range, came into use about 11,700 years ago, archeologist Michael Kunz of the Interior Department's Bureau of Land Management said Wednesday. It provides the strongest evidence to date that the first North Americans came across what is now the Bering Strait from Siberia in waves of immigration, rather than in one brief burst of movement as many researchers had previously believed.
The site is particularly important because the people who inhabited it were culturally and technologically distinct from peoples of Siberian origin who lived in Alaska a few hundred years later, Kunz said. But the culture at the mesa site is very similar to that of the Paleoindians who occupied the vast expanses of the Great Plains and desert Southwest slightly later. Remants of that culture have never been found north of Wyoming.
Most scientists had believed that the Paleoindians who lived in what is now the United States were descendants of the previously identified Alaskan cultures who developed their own culture as they migrated southward. The new results, revealed Wednesday at a news conference in Washington, suggest that the Paleoindians arrived in Alaska with their culture and technology already formed, although where they came from is still a mystery.
"I'm very excited because this is the first time we've gotten a good, solid Paleoindian site (from one culture) in the Arctic with completely reliable dates," said archeologist Robert L. Humphrey of George Washington University in Washington, D.C. Evidence is growing, he said, that "people were wandering across the Bering Land Bridge" at least several times "and perhaps hundreds or thousands of times."
Scientists now need to find where the Paleoindians came from, said archeologist Curtis Wilson, also with the Bureau of Land Management. "The question is, if people were moving across the land bridge, then why haven't we found sites like this in Siberia?"
Unfortunately, Humphrey said, "We don't have any good surveys of Siberian archeology. It's really in its infancy, and we need to do much more work to see what turns up over there."
The peopling of the Americas has long been a subject of hot dispute. Researchers agree that modern humans arose in Africa and Asia and migrated to the New World much later. The most likely route of migration is the Bering Land Bridge, also known as Beringia, which was uncovered during the last Ice Age when a significant portion of the world's water became locked in polar glaciers, lowering sea levels.
Indigenous populations could have moved across the bridge--which may have been hundreds of miles wide--in search of new food sources without ever realizing that they were traveling from one continent to another.
The earliest documented habitation sites in what is now the United States were so-called Paleoindian sites in New Mexico and Arizona, dating from 11,000 years ago. Other researchers have reported finding American sites ranging from 13,000 to more than 20,000 years old, but the accuracy of those dates have been sharply questioned and the dates are not widely accepted.
Kunz discovered the mesa site while studying the potential environmental impact of oil and gas explorations in northern Alaska. The site is accessible only by air, and the discovery itself was "dumb luck," he said.
Radiocarbon dating of campfire remnants suggests that the mesa was used for a 500-year period beginning about 11,700 years ago, abandoned for about 1,000 years and then used for another 500. Kunz notes that the 1,000-year period of disuse was characterized by an unstable climate during which the weather was much colder than during the periods of habitation. He suspects the inhabitants stopped using the site when game became scarce in the area.
The mesa, which covers about five acres, towers nearly 200 feet above the tundra floor and commands an unobstructed 360-degree view of more than 50 square miles, which would have made it ideal for spotting animals such as the now-extinct woolly mammoth and bison.
Kunz speculates that the Paleoindians climbed the mesa to spot their prey and whiled away the hours of waiting by making spears, lances, throwing sticks and other weapons. What he has found at the site are the residues of campfires and such tool-making, as well as the tools themselves.
Scientists have found what they believe to be the oldest documented site of human habitation in North America, about 150 miles north of the Arctic Circle.