Paleo-Indians Settled North America Earlier Than Thought, Study Suggests
[Writer] This is research news from U-I-C – the University of Illinois at Chicago. Today Steven Forman, professor of earth and environmental sciences, talks about work that he and a team of researchers conducted to scientifically date human artifacts excavated in central Texas. Their findings provide evidence that humans settled in North America earlier than previously estimated.
Here’s Professor Forman:
[Forman] We’ve had the good fortune to work on an exciting archaeological site not far from Austin, Texas. This site contains some of the best evidence for early human occupation of the North American continent.
This site has a sequence of artifacts that span from about 7,000 years ago to – what we’ve dated – about 15,000 years ago.
What’s really special about this site is that we’ve found artifacts below the well-known Clovis horizon, which is dated around 13,000 years ago. And below this Clovis horizon we found a technology that uses cores, blades … actually we found a piece of ochre that could be used ceremonially.
These materials were dated by a relatively new technique called Optically Stimulated Luminescence Dating. That technique dates the mineral grains inside the sediments directly.
At this site there was no radiocarbon data available at all, so the only way we could strain the age of this site was using this optical dating technique.
The optical dating technique agreed with independent ages from artifact levels that are above the oldest artifact level.
We collected a large number of samples – about 50 samples – in very tight order going up this sediment column, and we dated it by looking at various minerals, feldspar and quartz minerals. We dated it by different techniques and we got the same age no matter how we looked at it. And we reproduced this twice and basically got the same answer.
So this is the first time in which cultural complex, especially one this old, has been constrained by this luminescence dating method. And it basically gives a firm foundation for understanding when human beings came into North America.
There are other sites that have evidence that are this old, or nearly this old, but this is the first one with numerous artifacts, so you can really understand the earliest technology that humans were using in North America.
[Writer] Steve Forman is professor of earth and environmental sciences.
For more information about this research, go to www.news.uic.edu, click on “news releases,” and look for the release dated March 24, 2011.
This has been research news from U-I-C – the University of Illinois at Chicago.