We know Earth is old. Scientists estimate that our planet formed around 4.5 billion years ago. But how old is it exactly? And ...

Geologists recently dated the age of Watersmeet gneiss, a type of rock in the Upper Peninsula, as the oldest in the U.S. Here ...

A weathered sign in the Minnesota River Valley proudly proclaims: “World’s Oldest Rock.” Erected in 1975, it marks a 3.8-billion-year-old gneiss — or so scientists thought.

Microfossils found around the world contain specimens that don’t ... As their name suggests, these ancient rocks contain the tiny fossilized remains of protists and bacteria, and when University ...

In a recent study, geologists say Michigan is home to the oldest known rock in the nation. Watersmeet gneiss is found in Michigan's Upper Peninsula. Minnesota's Morton gneiss previously held the ...