For many years, scientists have thought that the first Americans came here from Asia 13,000 years ago, during the last ice age, probably by way of the Bering Strait. They were known as the Clovis people, after the town in New Mexico where their finely wrought spear points were first discovered in 1929.
But in more recent years, archaeologists have found more and more traces of even earlier people with a less refined technology inhabiting North America and spreading as far south as Chile.
And now clinching evidence in the mystery of the early peopling of America — Clovis or pre-Clovis? — for nearly all scientists appears to have turned up at a creek valley in the hill country of what is today Central Texas, 40 miles northwest of Austin.
Given the lack of sufficient organic material buried around the tools, the radiocarbon dating method was useless. Instead, earth scientists at the University of Illinois, Chicago, used a newer technique known as optically stimulated luminescence. This measures light energy trapped in minerals to reveal how long ago the soil was last exposed to sunlight.
Steven L. Forman, who directed the tests, said that 49 core samples were drilled from several sections of the sediments associated with the tools. When the data were analyzed, they consistently yielded the same ages. “This was unequivocal proof of pre-Clovis,” he said at the news conference.
Until recently, Dr. Waters said, archaeologists had probably overlooked earlier artifacts because the Clovis points are so distinctive and, in contrast, the pre-Clovis material has no hallmark style calling attention to itself.
“Finally, we are able to put Clovis-first behind us and move on,” he said.
Edited by damian5000 - 3/28/11 at 8:18am