Hindcasting the Grand Canyon: Geologist Rejects Dam Breach Theory

A geologist rejects the idea that an ancient lake spilled and carved Grand Canyon, but maybe he misrepresents the theory.  Besides, how can geologists “hindcast” an unobserved event without philosophical assumptions?

“Grand Canyon Carved by Flood? Geologist Says No,” reads a headline on Live Science, but the URL is stronger: “Megaflood debunked as Grand Canyon cause.”  Debunked is a strong word.  It implies permanently laid to rest, or falsified, by a concurrence of geologists.  In the article by reporter Becky Oskin, however, it appears that the debunking is just the opinion of one geologist, Bill Dickinson, an emeritus professor of geology at the University of Arizona in Tucson, who could provide no better explanation.

Tracing the history of the Grand Canyon is controversial. The deep gorge exposes a billion years of Earth history in its candy-colored cliffs, but geologists can’t agree when it formed, or exactly how.

A long-standing hypothesis by both creationist and secular geologists places a vast lake, called Hopi Lake, to the southeast of the current canyon, proposing that a dam breach carved at least much of the canyon rapidly and catastrophically.  The Painted Desert and other remnants called the Bidahochi Formation would be remnants of the old lake bottom.

Dickinson doesn’t believe the dam breach is a valid story, so he said “my main purpose is to dismantle it.”  He argues that the lake would have been too shallow, and that the waters could not have climbed over the Kaibab Upwarp.  This argument, though, overlooks the proponents’ scenario that the upwarp and the dam breach were tied together.  Dickinson and others mentioned in the article additionally argue that there’s no way the lake could have existed for 10-20 million years.  Creation geologists, however, do not need the millions of years, while secular geologists have no agreement on the sequence of events in the region, begging the question that the lake required the time.

It would seem hard for Dickinson to triumph over a competing theory when he is admittedly baffled by the origin of the canyon:

Knocking down Hopi Lake leaves a major puzzle: What was the course of the Colorado River before the Grand Canyon deepened? Some geologists think the early Colorado River flowed south into the lake….

“One of the hardest things to hindcast is to know how big a river you’re looking for in Grand Canyon country,” he said. “What was the river like up in Utah? I hope that if people would just abandon the Hope Lake spillover game, their thoughts would lead them on to worrying about Utah.”

Although Dickinson presented a proposal that the ancestral river flowed northwest across northern Arizona, his idea hardly accounts for many features of the canyon, including its crossing the Kaibab plateau.  Oskin implied that no other geologist is likely to come up with a better idea any time soon: “Part of the challenge of solving the Grand Canyon’s history is that so much has changed in the ensuing millions of years: climate was different then, the topography has changed dramatically, and tectonic forces continue to reshape the plateau.”

It seems hardly appropriate for Oskin to say the megaflood theory has been “debunked” when all the other theories have just as many or worse problems.  Oskin misrepresented the megaflood theory by assuming the millions of years as part of the story.  It’s the millions of years that are a large part of the problem with competing theories.  This was no debunking; it was rather a story of a man on a mission to discredit competition so he could present his own fallible hindcast.