I’ve always heard the Grand Canyon was created by the Colorado River. Now my brother-in-law comes along and says that kind of thinking went out with the carburetor and the current idea is, the Canyon was created by an event, like an earthquake. He says there was not enough time for the river to have done the job by erosion alone.
What’s the story? Is the conventional wisdom being challenged - or is my bro-in-law pulling my leg?
Sorry, this was intended for GQ. I’ve asked DavidB to kindly move it to the proper forum.
Your brother-in-law is either pulling your leg big time, or else he heard some bit of misinformation from someone else. Obviously, the Grand Canyon was formed when Paul Bunyon dragged his axe behind him on the way home from work one day. 
Seriously, the Grand Canyon has indeed been produced by the erosive action of the Colorado River. For a brief summary of Grand Canyon geology, go to Oops! 404 Error | Page Not Found and then click on the links for “Quick Look” >“Geology”.
Here is a good place to start.
Is your brother in law a creationist, by any chance? If so, he may believe that the world was created too recently for the river to do its work.
Funny, I just spent 13 days on the Colorado, rafting through Grand Canyon.
When you ask about what “created” the canyon, you could be asking two different things–how were the rock layers formed, and how did there come to be a deep canyon in that rock.
Basically, there are a lot of different theories about how the layers of rock were formed. But the general consensus remains that the Colorado was the major force in the formation of Grand Canyon.
It may seem hard to believe that a little river could make a big canyon like that, but with a little knowledge of river dynamics, it appears quite possible. The Colorado is a huge volume river. All that water stirs up sand and rocks, and those help scour away at the bottom. Also, until 70 years ago, there were no dams on the Colorado. Naturally flowing rivers do not have a constant flow–in flood conditions, huge boulders move around, also creating erosion. Plus, most of Grand Canyon’s layers are very soft rock–limestones and sandstones. These are fairly easily worn away.
There is a little more to it than that. Yes, it was caused primarily by river erosion, but the earth was also pushing itself up into it thereby exacerbating the action and spreading the uppermost sections of the canyon.
Think about it. The GC is almost 40 miles wide at some points. Thats a heck of a lot of water to be rushing through the canyon. Check out the major slot canyons of S. Utah to see what erosion alone will do. Very deep, very thin canyons.
If you watched the Flintstones you would know that it was indeed created by a river. The other version I heard as a kid was that some giant bloke dragged his axe along the ground on his walk home from working in the forest one day after he was fired or something…and created the grand canyon!!
Some ppl are so gullible!
Yes, erosion works very slowly, but there’s still plenty of time–all the time in the world, so to speak.
Or, from another perspective, consider this: we can directly observe right now that the Colorado River is continuing to erode and depen the Grand Canyon; there’s no reason to assume that it hasn’t been doing this all along. (A little uniformitarianism there for ya!)
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Think about it. The GC is almost 40 miles wide at some points.
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You sure about that? Im not saying its not true but i’ve never heard of it being 40 miles wide at any point. Got a cite?
When the earth was a teen, it had bad acne & couldn’t resist scratching & popping its zits, one of which became the Grand Canyon. In fact, “canyon” is Spanish for “zit of the earth”.
All of the sites I checked seem to indicate the GC is 18 miles at its widest.
A site that seems to scientifically discuss whether a “creationist” view of its formation might be correct is here
There was an article in the New York Times (June) that discussed the current theories as to the formation of the Grand Canyon. And yes, some legitimate (non-creationists) geologists argue that the river couldn’t have formed the canyon as is.
For $2.50, you can check it out yourself at the New York Times site.
My brother, a creationist/geologist (he was “born again” after he got his degree) believes it was carved after the Great Flood’s waters receded.
Question he couldn’t answer: then why aren’t there “Grand Canyons” all over the place?
18, 40, what’s the difference? I’ve never heard of a river 18 miles wide, either.