Researchers at St. Cloud State University say they have reason to believe that a site in the Boundary Waters Canoe Area Wilderness was home to a settlement 16,400 years ago, which would make the habitation the oldest in Minnesota.
They base it on testing of soil samples collected around Knife Lake, along the U.S.-Canada border. The St. Cloud Times reported Monday that anthropologists want to conduct more tests before drawing firm conclusions.
Associate professor Mark Muñiz said it would fit with a theory that people lived along the edge of glaciers as they receded. It challenges previous beliefs that glacier-led flooding in northern Minnesota caused the earliest humans to inhabit the south.
The excavation sites are believed to be where people quarried siltstone for tool-making. Muñiz said test results from Knife Lake show habitation 16,400 years ago, plus or minus 2,000 years.
"That opens the door wide for it to be one of the oldest sites in Minnesota," Muñiz said.
The professor has led several trips to that area to examine stone tool-making sites of the Paleo-Indians who inhabited far northern Minnesota.
The researchers have taken great pains to protect the evidence. They collected the samples under skies lit only by the moon and stars to protect them from exposure to light, which is key to testing soil age. They wore headlamps that shined red light and collected two samples of soil that were tested with a method called optically stimulated luminescence.
That type of testing uses ultraviolet light to measure how long the soil has been buried and helps date the artifacts that are found at the same depth as the buried soil.
Muñiz's team is applying for another grant to test other soil samples to get more data about the possible age of the soil where the stone tools were made.
His findings run counter to the prior theories that the area had not yet recovered enough to support plants and animals after being scoured by glaciers. It has long been thought that the first people to live in the Arrowhead region arrived hundreds, if not thousands, of years after Paleo-Indians appeared in the southern part of the state.