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Today's tech opens window to the past

March 25, 2022

Laurel Period ceramic sherds.
Laurel Period ceramic sherds from the Superior National Forest. Residue from the top left sherd was radiocarbon dated. USDA Forest Service photo.

MINNESOTA—Thanks to modern technology, an ancient Native American cooking vessel discovered in Superior National Forest’s Boundary Waters Canoe Area Wilderness, has been dated to 1,600-1,750 years ago (254-403 Common Era). In partnership with the USDA Forest Service, scientists at the University of California-Irvine conducted radiocarbon dating on carbonized food residue found on the interior of a sherd (broken piece of material) from the ceramic vessel. The sherd’s decorative elements are associated with the Laurel Cultural Tradition, which was prevalent in the Upper Midwest and Canada approximately 1,200-2,100 years ago.

As shown by this discovery, remnants of the Laurel culture have been well preserved in northern Minnesota and the wilderness. “The Laurel world was so vast, extending from Lake Superior up into Manitoba and Ontario. Laurel people were the earliest in this area to adopt mound building and continental trade networks,” said David Mather, National Register archaeologist for the Minnesota State Historic Preservation Office. “Out of that large area, the wilderness has perhaps the best representation and preservation of all that history. It is powerful to connect an artifact—in this case, a meal that was cooked—to a specific point in time.” 

“The site location and artifacts suggest a long history of ancestral Native American use of the site during the summer months for both fishing and manoomin (wild rice) processing; however, the radiocarbon date gives a really specific point of time to contextualize that use,” said Lee Johnson, Superior National Forest archaeologist. “We are fairly confident we have sites on the forest that are as old as 9,000 or 10,000 years old, but it is really rare for us to get a good radiocarbon date to confirm precise dates of human use.” 

Located in the Border Lakes region, this northern Minnesota site has three distinct cultural occupations evidenced by archaeological finds:

  • Fur trade era (150-300 years ago) artifacts including trade beads, musket balls and kettle brass. 
  • Woodland period (around 400-2,100 years ago) artifacts consisting of lithic debitage and tools, animal remains, copper tools, ground stone tools and Laurel, Blackduck and Sandy Lake ceramics. 
  • Undated, pre-Woodland period artifacts consisting of Hixton Silicified Sandstone debitage (flakes and other material removed during the course of reducing larger stones into finished tools), a hammerstone and native copper.

Archaeologist working at Superior National Forest site.
Superior National Forest archaeologist Lee Johnson works at the Superior National Forest site where the ceramic sherd was excavated. USDA Forest Service photo.

“This site is a good example of how much artifacts can tell us, and why even removing one artifact from its context can impact our knowledge of an area,” said Rachel Hines, forest archaeologist. “This site had several key artifacts, including the obsidian flake and the ceramics with residues, which contributed significant information to our interpretation of people in the Superior National Forest over the centuries,” she said. 

Preserving these sites and the stories they tell is vital for connecting with and accurately understanding the land and the cultures that came before us. Removing archeological artifacts is not permitted on the Superior, including from the wilderness. “Anything older than 50 years is considered an artifact, which is often surprising to people. Even bottles, cans and items that look like trash can tell us a lot about a site,” Hines added.

Staff from the Forest Service’s Northern Research Station in Houghton, Michigan, helped prepare the analyzed samples. The dating technique, referred to as an absolute dating technique, measures the amount of Carbon 14, a radioactive isotope, present in an organic sample. As Carbon 14 decays at a set rate over time, absolute dating indicates the time period of an artifact based on the amount of Carbon 14 remaining in the sample.

“It is important to get accurate dating along with utilization, to demonstrate the sophistication of the people and how they have used the land for thousands of years,” said Jaylen Strong, Bois Forte Band of Chippewa tribal historic preservation officer. “Artifacts like this help to improve the knowledge of people who used this land that can often be misrepresented.”

This radiocarbon dating builds on previous analyses from the same site. In 2007, an obsidian flake from this Superior National Forest wilderness site was sourced to Bear Gulch, Idaho. The flake’s origin indicates that trade networks extended there from present-day Minnesota.

Archaeologists usually find “flakes” of the debris from making stone tools, referred to by archaeologists as lithic debitage; however, sometimes tools are found. Some tools are diagnostic, which means they can be linked to a specific cultural group and roughly dated. Most lithic materials recovered from this site were locally occurring like quartz, Knife Lake siltstone and Iron Range quartz.

Map showing original sources of different artifacts in relation to Superior National Forest.
Traveling, trading and living off the land brought pieces of the past to the now Superior National Forest. This map depicts where some of the artifacts found in northern Minnesota originated. USDA Forest Service map.

Other lithics were exotic materials, including Knife River flint, which occurs in western North Dakota; Swan River quartz, which comes from Canada, northern Montana and North Dakota; Hixton Silicified sandstone, which occurs in Wisconsin; and obsidian from Idaho. These findings reiterate the extent of the Native American trading networks of the time period.

Researchers from Lakehead University in Thunder Bay, Ontario, also identified maize (corn) and manoomin (wild rice) starch residue on ceramic sherds and soil samples at this site in 2010, pointing to available food sources at the time.

“It is exciting for us to get a good radiocarbon date from the forest, as the soils are shallow and there is a history of contamination from wildfires,” said Johnson. “The dating techniques helps us in interpreting the long history of human-landscape interaction, the wide-ranging trade networks, and Native American land tenure in the Superior National Forest and the wider Border Lakes region.”

Visitors today come to the Forest and the wilderness because of beautiful campsites, fresh water, clear skies, wooded forests, abundant wildlife and much more. However, people have always been traveling, trading, hunting and gathering, and living off these lands and lakes, and through this research, we can better understand the rich history of the area.

 

https://www.fs.usda.gov/inside-fs/delivering-mission/deliver/todays-tech-opens-window-past