The Debate on the Age of the Grand Canyon

No, not whether it was formed during Noah's flood. This debate's much more interesting:

Visitors to the Grand Canyon always want to know: How old is it?

Park rangers are instructed to tell them that the canyon has been carved by the Colorado River for the past 5 or 6 million years. The park's Web site, under Frequently Asked Questions, notes that the rocks exposed by the canyon are up to 2 billion years old, and then adds: "The Canyon itself -- an erosional feature -- has formed only in the past five or six million years. Geologically speaking, Grand Canyon is very young."

That might need revision. The canyon is more like 17 million years old, according to a study published today in the journal Science.

And the Colorado River may not be the only river involved in its formation. The study contends that a smaller river cut the older, western part of the canyon. Gradually the canyon formed from west to east on westward-flowing river. Then something happened about 5 or 6 million years ago -- what, exactly, is unclear -- to accelerate dramatically the rate of the canyon-carving.

Be interesting to see how this one turns out.