Articles for tag: oldest rock in the U.S.

Michigan’s Gneiss Surprise: America’s Oldest Rock Found in the Upper Peninsula

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 geological history. Scientists say a new study shows the oldest known exposed rock in the United States is nestled deep in the forests of Michigan’s Upper ...