Billion Years Ago, a Rift Nearly Split North America in Two and It Left Behind a Mysterious Scar Around a billion years ago, a geological event occurred in North America that could have completely ...

The Birth and Structure of North America’s Hidden Rift. The Midcontinent Rift stretches in a horseshoe shape from Kansas northward to Lake Superior and then south again to Michigan. At its peak ...

A high-resolution, regional passive seismic experiment1,2,3,4,5,6 in the Rio Grande rift region of the southwestern United States has produced new images of upper-mantle velocity structure and ...