lpetrich

One creationist has claimed that the Grand Canyon is now thought to have been formed in only a few days. However, he may have mixed the Grand Canyon up with the Grand Coulee formations in the US Pacific Northwest, which were indeed formed with similar speed.

They were formed from the breaking of some ice that had dammed an ice-age lake, Lake Missoula in western Montana. That lake had a surface area of about 2500 mi^2 (6500 km^2) and a volume of 500 mi^3 (2000 km^3); the present-day city of Missoula was under 950 ft (300 m) of water. The draining of that lake created a huge flood in the Columbia River basin, producing landforms that look very similar to some of Mars's riverbeds. This flood was repeated several times as the glacier grew back each time, re-creating Lake Missoula.

J Harlen Bretz first proposed the giant-flood theory in the 1920's, noting features like giant ripples in the terrain that looked as if a giant flood had produced them. Other geologists rejected that theory for a long time, but it is now generally accepted.

However, those floods do not support Noah's Flood very well.

Mageth

He's wrong. How would that explain the dozen or so volcanic intrusions into the Canyon that have formed, created large backup lakes, and been eroded away, since the formation of the canyon?

lpetrich

I'm not familiar with that subject, but my point was that that creationist had likely been mixing up the Grand Canyon with the Grand Coulees.

And if the volcanoes had erupted some easily erodable rock, then you would certainly be correct; the canyon has a stepped sort of appearance, which suggests that some of its layers erode faster than others.

Mageth

I've heard creationists using the "fast erosion" story for the grand canyon before. It quite simply doesn't fit the evidence. The intrusions I mentioned above are just one of the problems. (that would be, what, 3 volcanic eruptions, and 3 total erosions, every 1000 years since the flood?)

John Solum

If you're referring to Carl Kerby, he was indeed referring to the Grand Canyon. He started that segment of his talk with an overhead of the cover of Science News that had a picture of the Grand Canyon with the headline "Erosion, vast and fast." After he put that up, he said that scientists (he referred to them as non-Christian scientists) now say that the Grand Canyon was carved in a matter of days. I haven't looked up that edition of Science News yet, but I'm willing to bet it doesn't say that.

Mageth

Well, it was carved relatively "fast" in geologic time, IIRC the canyon itself is only between 20-35m years old. The strata, of course, are much older. The oldest, the Vishnu schist (I love that name) is @1.7 billion years old. The youngest, the Kaibab limestone, is @250m years old. BTW, the most damning evidence against the YEC in the GC may be the several unconformities, millions of years of missing rocks between strata. Flood geologists who claim sedimentary layers were laid down en masse by the flood should choke on this chicken bone, IMO.

[ February 06, 2002: Message edited by: Mageth ]</p>