Why only one Grand Canyon

Hello, Spicket, welcome to EvC.You seem to be starting off on the right foot. Asking questions is always a good idea.Your question about the nature of the canyon isn't by itself a bad one.However, there is a very important point to make with all the many, many different issues that come up in these kind of discussions:You can never (or rarely) take one piece of information and fly with that. Any speculation you might have over what happened or didn't happen has to deal with all the information available.There is a great deal of information about the nature of the geology of the grand canyon that has to be dealt with to construct an even vaguely reasonable suggestion about it's formation. Some of the suggestions may be shown to be untenable when just a few bits of that information is considered.You might want to do a bit of research to find out what some of those other facts are. If you continue with the right tone here you'll find that many here will be glad to point those out to you too. (Some pretty frequent posters are actual geologists).Just remember the basic point. It does no good to deal with any one fact. They all have to fit into the picture you are painting.

Many Grand Canyons?I think you'd have to spell that out. I did a little look and found something about the Blyde River canyon in South Africa. It is, apparently the third largest in the world.Sound pretty impressive, 600 to 800 m down and the park it is in covers over 22,000 hectares( 4.5 acres each). So pretty grand.However the grand canyon is about 2,000 m deep at it's deepest and the complex covers over 1.2 million hectares. I don't know what number two is. But compared to the Grand Canyon the Blyde canyon is pretty "ungrand".There are, of course, a lot of canyons all over the world. Almost everywhere a river runs there is something that one could call a canyon. But the conditions that allow for the formation of really big canyons are not so common it appears.

It appears that, in spite of his claims of expertise, d yankee isn't going to be quick to answer questions.It might be early to call a "hit and run" but it looks like it.