When you think about archaeology, your mind probably goes to a scene of an excavation site — people with hammers and dressed in khaki, digging away in an arid, dusty landscape.
But although archeologists dig below the surface for artifacts left behind by civilizations past, archaeology is also done way below the surface — underwater. That’s where Dr. Ashley Lemke comes in.
She’s an archaeologist and an associate professor in the anthropology department at UW-Milwaukee, where she leads the program for underwater archaeology, or the study of submerged landscapes.
“Essentially, we're very interested in the human past, so we don't do dinosaurs and we don't do UFOs,” Lemke explains. “But anything that people did that has now wound up underneath water, that's what we're interested in.”
Great Lakes shipwrecks might come to mind here, but Lemke’s work deals with much older, hunter-gatherer sites.
A discovery on Lake Huron
In 2014, Lemke worked on a University of Michigan project that uncovered 9000-year-old caribou hunting sites at the bottom of Lake Huron. Submerged beneath over 100 feet of water, the team discovered ancient “drive lanes” — used to herd caribou into straight lines, making them easier to hunt.
“Nobody had any idea that people in the Great Lakes were hunting using those methods. Nobody had any idea that the sites that were submerged would be intact,” Lemke says. “They're 9,000 years old. There's forests down there. There's wooden trees that are still rooted in place because the cold freshwater is so good for preservation.”
These sites lie on lands that used to be above sea level at the end of the last ice age, when Great Lakes water levels dropped hundreds of miles lower than they are today.
“In the Great Lakes, we had those lower water levels where there was more land available for people to live,” Lemke explains.
Lake Michigan offers a new 'puzzle'
Now, Lemke is searching for similar sites on Lake Michigan. Her crew uses a 25-foot fishing boat and various sonar tools to scan the lakebed for stone tools and hunting structures.
“We know more about the surface of Mars than we do about the bottom of Lake Michigan,” she says. “You'd think we'd know so much about the bottom, and we don't – so most of our research starts out with just mapping the lakebed. We use side-scan sonar, multi-beam sonar, and something called a sub-bottom profiler that actually penetrates below the lakebed to see if there's things that are buried there.”
Lemke says archaeology is “like putting together a puzzle” — but without all the pieces and without the picture on the box. However, she says the biggest challenge is severe weather and turbulent waters out on the lake.
“Oftentimes we're going quite far out into the middle of Lake Michigan, so you have to have a boat that can handle that,” she says. “You have to a boat with enough space and enough power to run all this equipment.”
Looking ahead
For Lemke, the best part of the project has been working with middle and high school students from the St. Francis School District. The students built an underwater robot to assist with research and discovery.
“They're so unbounded in their creativity, and they're just not stressed about anything,” she says. “We would be like, ‘Oh, well, you know, that's not going to work because it's expensive,’ or, ‘That won't work because of scheduling,’ and the students are like, ‘Let's just make it happen.’ And they're right, like that's the attitude that we should have.”
The underwater archaeology program at UW-Milwaukee is growing fast, with students applying from all over the world, Lemke says. And with potentially tens of thousands of miles of ancient hunting lands submerged underwater today, our knowledge of the Great Lakes' indigenous inhabitants is woefully incomplete. For now, it’s up to underwater archaeologists to fill in the gaps.
“For hundreds of years, people have done archeology, and we make all these models and all these ideas of what we think life was in the past,” Lemke says. “But we're missing a lot of that story if we don't look underwater.”
You can listen to Lake Effect's Audrey Nowawski onversation with Dr. Ashley Lemke’s full conversation with Lake Effect’s Audrey Nowakowski above.
