Scientists have discovered that the oldest intact rock in the United States is not in Minnesota or Wyoming—but in Michigan’s Upper Peninsula. The 3.62-billion-year-old Watersmeet Gneiss is rewriting ...

“They may have documented [the United States’] oldest known rock,” he says, “but the challenge to young readers will be to discover an even older rock.” Frost agrees. The 3.8-billion ...

Wyoming geologist Carol Frost and three of her colleagues have identified a new oldest rock in America. Found in Michigan, ...

The oldest rock in the United States has been discovered in Michigan, with zircons dating back 3.82 billion years.

The Search for America’s Oldest Rock: The Watersmeet Gneiss The new title-holder for the oldest rock in the United States is the Watersmeet Gneiss in Michigan, which dates back 3.6 billion years ...

"Taken together, the Archean rocks of the Wyoming-Minnesota-Michigan block represent the oldest continental crust in the United States, the nucleus around which the younger rocks of the nation ...