Animal bones, tools offer clues to life by the Minnesota River 8,000 years ago.
Eight thousand years ago, Minnesota looked like another world.
Prairie grasses covered the land, with trees sparse except in the extreme northeast. The landscape was extremely dry, with lakes reduced to waterholes and rivers withered to streams. Small groups of native people roamed the wild, hunting bison that were 50 percent larger than the species we know today. They camped in the river bottoms, close to water, fish and game.
Now archaeologists are getting a priceless peek at that ancient past, known as the Archaic Period, because of a rare campsite discovered along the Minnesota River in Chanhassen during a routine survey in preparation for bridge work.
“Basically, it’s like a time capsule — a very well-preserved record left pretty much intact of where it was deposited,” said archaeologist Frank Florin, principal investigator at the site, whose precise location officials are not revealing to keep away vandals and treasure hunters. “It’s exciting to know that you’re looking at things as they were 8,000 years ago, essentially.”
Florin found the site near the junction of Hwy. 101 and County Road 61, also known as Flying Cloud Drive.
Starting next year, the area will be excavated as part of a $54 million replacement of the Hwy. 101 bridge linking Carver County and Shakopee. Federal rules require an archaeological survey when such a project is underway to determine if anything of historic value would be disturbed.
The artifacts were buried 10 to 12 feet below the ground in an area mostly covered by peat, cattails and swamp.
Campsites in the river valley were occupied in a drier period of history, said Minnesota state archaeologist Scott Anfinson, probably by small groups of no more than 20 people. Over the centuries, the climate became wetter, river bluffs eroded and the campsites were covered with silt and soil and filled in as wetlands.
That’s why ancient sites are so rare, he said.
“Wet environments are very difficult to find, and very difficult to dig, but they’re very rewarding because of what you can get out of them,” Anfinson said.
The depth and lack of oxygen preserves not only stones and tools, but also organic material such as plants that can be analyzed and dated.
“We can actually say, ‘This spearhead was made by these people who lived at exactly this time,’ so we can get a huge amount of information,” he said.
Florin said some of the stones used as tools appear to have come from North Dakota or western Wisconsin, suggesting that the native people traveled some distance in their hunting or that they interacted and traded with other groups.
Craig Johnson, archaeologist for the Minnesota Department of Transportation, said part of the ancient campsite will be destroyed to install deep footings for new bridge piers next year, so a fall excavation is planned to retrieve additional artifacts that otherwise would be lost.
“We don’t have more than about a half a dozen of these archaeological sites from this period that are known in the Minnesota River Valley, so this is pretty significant,” he said.
In the initial survey work that found evidence of the encampment, Florin and a crew used soil core augers — similar to post-hole diggers with extensions — to remove samples of dirt, clay and mud and to screen them for artifacts. The team hand-drilled about 600 holes in the fall of 2012 and this spring.
They found artifacts in several spots along a 400-yard stretch that includes both public right of way and private land. There is at least one buried campsite, Florin said, and perhaps remnants of others.