Is the Grand Canyon Still Growing?

ByABC News
July 23, 2002, 12:37 PM

Aug. 1 -- Perhaps John Muir said it best. If you happened to find yourself unknowingly on the rim of the Grand Canyon, the chasm stretching before you would seem "as novel to you, as unearthly in the color and grandeur and quantity of its architecture, as if you had found it after death, on some other star "

That incredible site has humbled us all, including scientists who have struggled for decades to understand the mechanisms that gave us this great treasure.

But teams of scientists from across the country are scouring the canyon these days, and they are uncovering enough of the canyon's secrets to render most textbooks obsolete.

The evidence suggests that large sections of the canyon are much younger than had been thought, and some of the most dramatic features may be no more than 600,000 years old, making the canyon a geological infant. And although scientists had thought the cutting of the canyon by the mighty Colorado River was pretty well wrapped up more than a million years ago, the most recent research suggests it is still going on.

So the Grand Canyon appears to be a work in progress, not a fait accompli.

Sudden, Violent Floods

Many scientists have presumed that the canyon was cut gradually and at a steady pace by the flow of the river, but some remarkable research indicates that the cutting has been periodic, punctuated by catastrophic floods so huge they are hard to imagine.

According to research by scientists from the University of Arizona, the U.S. Geological Survey, and the University of Utah, one flood alone was 37 times larger than the largest known flood from the Mississippi River.

Scientists are in general agreement that the birth of the canyon started about 6 million years ago still just the blinking of an eye in geological time when the Colorado River formed its present path to the sea. To say that the river created the canyon is a gross oversimplification. But it was the dominant player, carving a trench that exposed layers of rock along its side to wind and water erosion.