A research team studying an underwater archaeological site at the bottom of Lake Huron in Michigan recently discovered flakes of obsidian, black volcanic glass, that originated from Central Oregon.

The two small flakes, each nearly a centimeter long, are the oldest and farthest east obsidian has ever been found in the United States. The discovery reshaped how researchers understand civilization 9,000 years ago, when caribou hunters used obsidian as stone tools during the last Ice Age.

The research team from the University of Texas at Arlington was left with several questions: How did the obsidian make it 2,000 miles east? And how much more exists outside the West Coast?

“You get excited and immediately your scientific brain is like, OK how did it get there?” said Ashley Lemke, assistant professor of sociology and anthropology at the University of Texas at Arlington. “Now we have some explaining to do.”

A laboratory confirmed the obsidian flakes came from Wagontire, a tiny unincorporated town in Harney County about 130 miles east of Bend. Central and Eastern Oregon have an abundant amount of obsidian, Lemke said.

She believes the flakes came off a stone tool as it was sharpened. The tool must have been traded between hunters several times over the past 9,000 years and ended up in Michigan.

Obsidian was a popular material for people thousands of years ago because it was easy to make tools out of it, Lemke said.

“Obsidian is special for archaeologists because we can trace it, but it was really special for people in the past because it was super sharp,” Lemke said. “Out of all the rocks you could pick, obsidian is one of the best. It was preferred by prehistoric people all over the world.”

Lemke and six other colleagues published a study last month with their findings.

The research team has been working at Lake Huron since 2009. They work on boats 50 miles off shore and use sonar and divers to uncover the ancient civilizations that were overtaken by water, similar to how a volcano buried Pompeii, Lemke said.

“No one has built anything over these sites,” Lemke said. “They haven’t been destroyed by farm fields or big buildings.”

The team has discovered stone structures, rooted trees and a campfire still filled with charcoal.

“That’s why we have been working there for so long,” Lemke said. “It’s not very easy, but the amount and the kind of data you can get is totally different than what you can get on land.”

Lemke and her colleagues plan to spend the summer continuing their research 100 feet underwater. They hope to uncover more obsidian from the sediment samples they collect.

“We are going to go and do more samples,” Lemke said. “We want to make sure if there is more we are going to get it all.”