Friday, March 30, 2012
KNIFE LAKE — The clear, deep water laps against the shores of Canada’s Quetico Provincial Park on one side and the edge of northern Minnesota wilderness on the other.
The Ojibwe name for what the glaciers created is Mookomaan Zaaga’igan, while the French fur traders called it Lac des Couteaux, or Lake of Knives. It’s on the shores of this remote lake, at least 15 miles from the nearest road and in water divided by the U.S.- Canada border, where Minnesota’s earliest history is being uncovered.
Those retreating glaciers left a scoured landscape of exposed siltstone, a silica-infused mud that hardened for millions of years into a high-quality source for Paleo-Indian stone toolmaking. And thousands of years after the last siltstone was harvested from Knife Lake quarries, researchers from St. Cloud State University are letting that stone speak for the first time about the earliest inhabitants of Minnesota.
“It’s rewriting the history for this area of Minnesota. We’re making a major contribution in understanding the very earliest cultures of humans to live in this part of the state,” said Mark Muñiz, associate professor of anthropology at St. Cloud State.
Muñiz and three fellow researchers paddled and portaged to Knife Lake in the Boundary Waters Canoe Area Wilderness in August to continue digging for evidence that Paleo-Indians drawn to Knife Lake siltstone were the first humans to inhabit Minnesota.
If his theory is correct — and he found more evidence this summer to support it — Paleo-Indians first inhabited far northern Minnesota as glaciers receded 11,000-12,500 years ago. That would run contrary to the belief that the area had not yet recovered enough to support plants and animals after being scoured by glaciers. It would also be contrary to the 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.
Time, however, isn’t on the side of Muñiz. The area he is surveying was made accessible only by a huge storm in July 1999 that led to prescribed burns in the BWCAW in 2005.
The forest regeneration is quickly covering the siltstone quarries with new growth of sumac and jackpine, and that growth eventually will again close those valuable sites to exploration.
Quarries , work sites
The flintknapped siltstone artifacts Muñiz has found at Knife Lake show Paleo-Indians quarried the stone from the high outcroppings that were visible before the forests matured and blanketed the landscape thousands of years ago. There are associated work sites where tools were fashioned, where people lived and where animals were harvested and necessities of life were made, Muñiz said.
Those first inhabitants probably used those tools to hunt caribou and possibly even mammoths and mastodons as they lived in one of the last ice age communities in the United States. Knife Lake served as a beacon during yearly, seasonal migrations of Paleo-Indians, who carried away the siltstone tools that have been found east to Thunder Bay and in eastcentral Minnesota, Muñiz said.
High-tech dating techniques will narrow the time period in which the artifacts were made, but the style of toolmaking he’s found leads Muñiz to believe the prehistory of Minnesota will be rewritten to put inhabitants on the U.S.-Canada border far earlier than previously believed.
“It pushes back the timeline for a site in Minnesota that has been excavated, with evidence of people living here at such an early time,” he said.
Canadian researchers in the late 1990s noted siltstone quarries and possible tool manufacturing sites on the north side of Knife Lake. It took a natural catastrophe to kick-start the search on the Minnesota side of the border.
Muñiz returned to Knife Lake in 2010, and this summer he and two graduate students went back along with Lee Johnson, a Buffalo native and Superior National Forest archaeologist.
They excavated a site they previously had surveyed and they took another walking tour of a site they had discovered on a previous trip. They also took a fresh look at a new site that yielded even more promising results.
“We’re on the edge of what could be a massive site,” Johnson said. “This is one of a kind, untouched and preserved, a quarry and workshop sites around us. It really is an important site for the history of Minnesota.”
The group members do three types of exploration. First, they walk the terrain and look for artifacts laying on the surface. If they find enough, they might do a shovel test to see what’s below the surface. If that shovel test reveals more artifacts below the surface, they might do a full excavation of a unit.
The work is done under the watchful eye of Johnson, who is responsible for about 2.3 million acres of forest, including developing preservation strategies and projects for things such as erosion stabilization.
He also consults with Ojibwe tribes to determine which areas have sacred significance for tribes, such as wild rice stands and sites where medicinal herbs are collected.
“One of the reasons I’m here is to determine whether there are significant things here that haven’t been disturbed and how we might better protect them,” Johnson said.
Graduate studentsTyler Olsen and Jennifer Rovanpera finished excavating a 1-meter-by-1-meter unit that had been started on a previous trip. They and Johnson and Muñiz walked through the new site, looking for surface artifacts that might support further exploration.
And Muñiz and Johnson did a shovel test at a separate location by digging a foot-wide hole and carefully removing and sifting its contents 10 centimeters at a time until they were 40 centimeters deep.
They removed some flakes that were discovered during the sifting, then they replaced the soil to refill the hole.
Muñiz used a GPS device to mark the locations of artifacts they found. There were siltstone chunks that had been flintknapped on one side (unifaces) and on both sides (bifaces). They found cores that likely would be shaped there or transported elsewhere and be shaped later. And they found layers and layers of siltstone flakes, the telltale sign that humans had used flintknapping to shape the razor-sharp stone into spear points, scrapers and blades.
“There are so many artifacts here that you can’t stop finding it,” Muñiz said.
And although he had found Knife Lake siltstone flakes and bifaces in previous trips that showed the style of human habitation dating to the glacial period, the August trip showed that Knife Lake was more than just a source of the valued stone.
“Now we’re establishing a complex of sites, rather than just one spot,” he said. “A complex of sites like that hasn’t been found anywhere in the state to my knowledge.”
What he didn’t find, and what he hopes one day to see there, is a finished spear point. It’s the equivalent of the Holy Grail for an anthropologist.
“I would like to find the unequivocal smoking gun,” he said.
Next: Lab work
Muñiz is confident the style of the tools being made gives him a good idea of the time period in which they were made. But he knows there are better ways to narrow the dating, and that starts in the lab.
Part of the $56,000 Legacy Amendment grant that helped pay for the 2010 trip also bought a high-powered microscope that he uses to analyze how the artifacts were used. The microscope can tell if the stone cut grass, scraped hide or chopped wood, for example, he said.
Soil samples also will help Muñiz close some of the gaps in his research and bring him closer to presenting his conclusions for peer review, an important step in gaining broader acceptance for his theory and his conclusions.
He and his fellow researchers in August also collected soil they hope to test. That collection was done under skies lit only by the moon and stars. Wearing headlamps that shined red light, they collected two samples of soil they hope to test with a method called optically stimulated luminescence.
OSL testing uses ultraviolet light to shine onto irradiated samples of sand that have been buried and not exposed to light for thousands of years. Being buried locks within the sand grains the age at which the soil was last exposed to light. OSL testing can measure how long the soil has been buried. It helps date the artifacts that are found suspended in the buried soil.Having an OSL date “would help tremendously,” Muñiz said. “That’s a real key thing.”
So is time.
The area the blowdown and burn uncovered is regenerating so fast that access to the quarries and work sites is gradually fading. As Muñiz and Johnson crisscrossed the worksites, they dodged sumac and jackpine, stepped alongside blueberry and raspberry plants and flushed partridge — all signs of a forest recovering from a fire.
Within three years, it could be so dense that Muñiz can’t get to the spots he wants to explore. The artifacts he is finding once again will be locked in place. And that’s the way it should be, Johnson said.
“We get a little sample of what’s here and then we let it be,” Johnson said. “And that’s a good thing.”