The Grand Canyon is younger than you think, say scientists

In recent years scientists have generally come to agree that the mile-deep gash in northern Arizona was probably carved by the Colorado River starting around six million years ago. But earlier this year researchers claimed in the journal Science to have found rocks in a cave near the western section of the canyon that proved the huge chasm was at least 17 million years old.

Now, in a rebuttal paper published this month in the journal Geology, Karl Karlstrom of the University of New Mexico and a team of researchers seek to end the debate once and for all. They argue that a combination of three faults in the area and upwelling hot mantle material pushed the region's rocks upward, causing the canyon to form in segments from east to west over the last six million years.