Underwater Archaeology
By Renè Wheaton
Exploring the bottom of Lake Huron for signs of ancient human life.
The bottom of Lake Huron is filled with more than shipwrecks—there are also clues left behind from ancient man.
LSA Professor of Anthropology John O’Shea found archaeological evidence of a 9,000-year-old hunting culture in the depths of Lake Huron, in collaboration with U-M Professor Guy R. Meadows, Director of U-M’s Marine Hydrodynamics Laboratories.
The discovery includes a low line of rocks 1,100 feet in length, which researchers believe were used during caribou hunts. The technique preys on caribou’s natural inclination to follow a straight line. O’Shea believes other stone structures could be hunting blinds, where hunters would have hid and then ambushed the animals.
O’Shea’s archaeological site is on the Alpena-Aberly ridge, a 10-mile wide crest that stretches more than 100 miles from Point Clark, Ontario, to Presque Isle, Michigan. The ridge, which is now beneath the modern Great Lakes, was once dry land that divided Lake Huron in half during the Lake Stanley period (10,000-7,500 years ago).
“That’s what has always been so tantalizing about these potential sites,” O’Shea says. “During the Lake Stanley time period, these sites were exposed. As the water levels rose they were inundated, and have never been touched since.”
For years, researchers like O’Shea have been excited about the potential archeological finds on the Alpena-Aberly ridge. But while scholars had some idea of where to look for clues left by ancient man, the what to look for was a little more elusive. Enter some much-needed serendipity.
“I was reading about reindeer herders in Siberia and how they don’t drive them like cattle or sheep,” O’Shea says. “The reindeer follow natural linear patterns. That led me to research in the Canadian Arctic that shows caribou hunters using similar techniques of building simple, linear stone walls to channel the animals. That gave us an idea of what we were looking for under the lake.” (Story continues below.)
While searching underwater, the U-M researchers had to rely heavily on high-tech acoustic, video, and sonar gear—and hope Mother Nature would do her part by providing calm weather.
“It’s a layered search strategy,” O’Shea says of the work. “The first step is to pick places that would have been good for hunters. We then search the sites with sonar equipment, creating extensive mapping of the bottom of the lake, and identifying different kinds of structures.”
Once promising sites were found, the team used a mini rover, equipped with a camera, to further investigate sites. The final step is sending in an archeologist trained in scuba diving.
The setting for the dive is an “awe-inspiring landscape,” O’Shea says. “It is out of sight of land, it’s outside of the shipping channels. It’s a surprisingly pristine place; there’s no debris out there and you can see using natural lighting—the visibility is like the Caribbean because the water is so clean. The first time you dive, you don’t get any work done.”
While the findings are thrilling for O’Shea, who is also the curator of Great Lakes archaeology at the University’s Museum of Anthropology, the prospect of further discoveries is what truly motivates him. The cold, fresh water of Lake Huron provides a unique environment that may have worked to preserve artifacts, possibly even organic materials that may be discovered when researchers are able to get a closer look at these sites.
“It’s very exciting to think what else might be down there for us to find,” O’Shea says. “We’ve also had interest from other departments, and so this research might spin off well beyond archeology. Isn’t that what a university is really all about? Bringing people of all different disciplines together to research and discover for the benefit of everyone.”