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

Head to Greenland’s west coast during the brief weeks of summer for a glimpse of gneiss—banded, metamorphic rock 3.8 billion years of age. This rock was likely formed when mantle and crust ...

Michigan, Minnesota and Wisconsin all feature ancient rocks known as gneisses — metamorphic rocks banded with various minerals — but an analysis determined that the gneiss in northern Michigan ...