Evidence of life beneath Lake Huron

Alpena-Amberley ridge was once a bridge to U.S.
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News

By Josh Howald

Scientists have discovered archeological evidence of life on an underwater ridge that stretches across Lake Huron from Amberley to Presque Island, MI.

“Basically the ridge is a 10-mile wide corridor,” said John O’Shea Wednesday afternoon, “that was a bridge across Huron when water levels were much lower (9,000 years ago).”

O’Shea is curator of Great Lakes Archaeology in the Museum of Anthropology and a professor at the University of Michigan. He co-authored the report, published in the June 8 issue of Proceedings of the National Academy of Sciences with Guy Meadows, director of Marine Hydrodynamics Laboratories and a professor in the departments of Naval Architecture and Marine Engineering and Atmospheric, Oceanic and Space Sciences.

The team, funded by the United States National Science Foundation, has found what it believes are remnants of an ancient caribou hunting camp used by some of North America’s earliest inhabitants.

“It fits with the landscape,” said O’Shea. “We have found an intact fire pit already.”

The report also details a 350m long “drive lane” of piled stones used by prehistoric hunters to drive animals into an ambush. Similar structures have been found in the Canadian Arctic.

“Many thought that such preservation could only survive in the Arctic due to later land use, farming for example. However, we have found all this unintruded land that was assumed destroyed under the lake.“

Because the water of Lake Huron is cold, and not acidic, O’Shea believes there is potential for finding all kinds of archaeological evidence.

“Previously in Lake Huron whole forests have been discovered, so this is an exciting time,” he said.

At its highest point, the Alpena-Amberley Ridge is 36-feet below the current lake level. Its path runs uninterrupted across Lake Huron.

This diagram shows the Alpena-Aberley Ridge, once a land bridge that divided Lake Huron in two. The United States is on the left, with Amberley in the bottom right hand corner.

“It’s truly a significant structure that would have once separated Lake Huron. Much of it is in water levels 40 to 120 feet below modern lake levels. There is no sediment on top, just sheer rock. It has a very Arctic look to it actually.”

The climate of our area would have been similar to the subarctic in the Paleo-Indian stage, between 7,500 to 10,000 years ago.

Work has already begun, with O’Shea’s team starting, quite literally, in the middle. Scuba teams were in the water last week. Though lake and light conditions are prime for archaeological searches, they have run into one problem.

“(The ridge) is covered in zebra mussels,” said O’Shea. “So  that poses the next big challenge for archeologists looking for artifacts and evidence of activity.”

The team is targeting layers of the limestone ridge, doing side scans and sending scubas to those places, and was pleased to have found chert, a rock which was used to make tools.

During initial research, O’Shea and Meadows used sonar equipment on the U of M’s new cutting-edge survey vessel equipped with underwater remote-operated vehicles with cameras.

“It’s just an old ocean fishing boat,” laughed O’Shea, who began work in Lake Huron years ago by studying shipwrecks. “It is heavy duty enough to withstand anything Lake Huron can give us but still allows us to go in shallow water. Basically you drive with a  joystick and take pictures with the sonar.”

The report has drawn the attention of researchers at the University of Sudbury, who hope to begin land surveys on the terrestrial side, Amberley and Point Clark, this summer.