By By Becky Oskin, Staff Writer
The Colorado River took the easy route when it carved the Grand Canyon through Arizona's ruddy sandstones and pastel limestones, a new study claims.
Instead of slicing through thousands of feet of unblemished rock, the Colorado River recycled ancient canyons, at least one of which was 70 million years old, researchers report today (Jan. 26) in the journal Nature Geoscience.
"I think the Colorado River found low places and paleocanyons and ancient topographies that led to theGrand Canyon," said Karl Karlstrom, lead study author and a geologist at the University of New Mexico in Albuquerque.
The new findings, which rely mainly on reinterpretations of other scientists' work, summarize decades of geologic sleuthing. But the study may do little to resolve the heated debate over the age of the Grand Canyon. For the past year, Karlstrom and others have stridently attacked work published Nov. 29, 2012, in the journal Science that suggested the westernmost Grand Canyon was 70 million years old. ...more