Geologists may have finally solved a longstanding mystery surrounding the Colorado River's largest tributary, which appears to have defied gravity and flowed uphill when it first formed.
The Green River originates in Wyoming and links up with the Colorado River in Canyonlands National Park in Utah. Around 8 million years ago, the Green River carved its way through the 13,000-foot-tall (4,000 meters) Uinta Mountains in northeastern Utah and northwestern Colorado instead of flowing around the formation. But in a new study, researchers argue this isn't possible without a mechanism to lower the mountains.
