Catastrophic floods built Grand Canyon

UPI ^ | July 20, 2002 | Dan Whipple

[gcruse]

Catastrophic floods built Grand Canyon

UPI Environment News

From the

Science & Technology

Desk

Published 7/20/2002 6:00 AM

GRAND CANYON NATIONAL PARK, Ariz., July 20 (UPI) -- Dams of volcanic rock laid across the Grand Canyon have burst repeatedly and catastrophically over the past million years -- most recently about 165,000 years ago -- carrying enormous onrushing floods and carving out much of the great landmark in the blink of a geologic eye, new research by U.S. Geological Survey and University of Utah geologists suggests.

The findings tend to support other new data indicating the canyon's Inner Gorge may be no more than 700,000 years old, much younger than earlier estimates of 3 million to 5 million years, said Robert Webb, a research geologist with USGS.

"The newer interpretation is that there was a basalt dike that crossed the Grand Canyon that's been dated at 770,000 year ago," Webb told United Press International. "So the Inner Gorge wasn't there then. It's been downcut since then."

Downcutting refers to the phenomenon that occurs when enormous volumes of water are unleashed by sudden removal or failure of natural barriers such as lava dams. In the case of the Grand Canyon, downcutting means the Colorado River did not form the canyon through gradual erosion over millions of years. Instead, intermittent dam failures unleashed massive flash floods, in at least one case carrying many times more water than the largest Mississippi River overflow ever recorded.

"Large sustained floods can cause rapid downcutting in bedrock," Webb said. A similar event on a smaller scale occurred in 1976 when Idaho's Teton Dam failed. The water flow left a distinctive profile in soils and on canyon walls, he said. The water level dropped extremely rapidly in a phenomenon called a decay curve.

"We have that curve preserved from a lava dam that failed in the Grand Canyon 165,000 years ago," Webb said.

The lava was deposited by a chain of volcanoes that runs across the Grand Canyon. Periodic eruptions created the dams, which blocked the river's flow. Over time, enormous quantities of water backed up, eventually breaching the dams and continuing the downcutting process.

Webb, who collaborated with University of Utah researcher Cassandra Fenton, said, "There's a big volcanic field that straddles the Grand Canyon" and was active relatively recently. A minor eruption probably occurred there around 1,300 years ago, he said.

The most recent basalt dam probably occurred between 100,000 and 120,000 years ago, Webb said. However, "The one we've worked on most was there 165,000 years ago." When the natural lava dam failed, it unleashed 15 million cubic feet of water per second -- 37 times larger than the biggest Mississippi River flood -- helping to carve the lower canyon.

"These were some high dams," Webb said. "We estimate some were more than 1,500 feet tall."

The lava dams also were inherently unstable. The researchers explained when the molten basalt lava met cold river water, it cooled almost instantly, forming fragile walls of glass. "When basalt hits water, it shatters into glass, and there is just glass all over the place in these deposits," Webb said.

Another piece of evidence is the short life spans of the lakes building up behind the dams. Webb said the lakes filled quickly under pressure from large snowmelts in the Pleistocene era, which lasted from about 2 million years ago to the end of the last ice age -- around 9,000 B.C. The lakes did not have enough time to form deltas, he said.

USGS geologist George Billingsley, one of the leading experts on the age of the Grand Canyon, said although Webb and Fenton's work adds more data, he still regards the age issue as unresolved.

"We don't have enough hard-core evidence to prove it one way or the other," Billingsley told UPI. "All we're saying is that there has been a lot of Grand Canyon cutting in the last million years."

Other geologists share the skepticism, he said. "There are still a lot of holes to fill in. We need more data. That's why I'm hesitating to say 2,000 feet (of canyon depth) was cut in a million years." But some work, like the Webb-Fenton work, is supporting the hypothesis, he said.

One theory the catastrophic flood work does not support is the biblical flood story in Genesis. Some creationists have taken evidence of a "young Grand Canyon" as grounds for biblical literalism. One company, Another Viewpoint, offers trips through the canyon explaining its features as the result of Noah's flood.

"It isn't directly relevant to something like the Noachian flood because in this case we know what the source of the flood is," Webb said. "It is not like a rainfall flood that happened over an entire watershed. This is a river being blocked."

He added, "But it is a nice parallel to make. We do have in the geologic record where sometimes we can tell if they are rainfall related ... It's important to stress that a lot of the biggest floods worldwide have not been the result of unusual climatic events. They have been the result of the failure of a natural dam."

(Reported by Dan Whipple, UPI Science News, in Broomfield, Colo.)

Copyright © 2002 United Press International
 

[Consort]

Uncivil engineers build damns.

[gcruse]

Uncivil engineers build damns.

Heh.  I like that.  Say, if beavers building
dams is a natural thing, why isn't humans
building dams natural, too?

[frodolives]

Oh! Thanks for the reference. This is of some interest to us folks in North Idaho and Eastern Washington. Stand up at the top of Schweitzer Mountain Ski hill and see lovely Lake Pend O'rielle and imagine the outpour! Nice PBS special on this recently.

[TomB]

bump

[dalereed]

They ought to build dams the entire length of the Grand Canyon and contain the water for human use and electric generation especially since the enviros were successful in stopping flights in the canyon so a few of them could waddle around in it undisturbed.

Luckilly, I was able to make 2 flights halfway down in the canyon the entire length of it before they stopped it. That is a sight to behold, especially the one I made in the late afternoon in the winter with snowcapped tops of all the flat spots.

[Sabertooth]

The main reason they don't think the canyon came from Noah's Flood: there was no single world-wide flood.

I checked your link, and ya know, the preamble stinks. Ken Harding should have just gotten to his list and made a scientific argument. But no, he couldn't resist gratuitous dainties like...

"While the biblical flood story is almost certainly derived from the earlier Babylonian flood mythology..."

What does this have to do with science?

And what is the source of Harding's "almost" certainty? He doesn't say.

However, it's popular to believe that the Genesis account of the Flood is derived from that of Gilgamesh, and odds are this is the basis of Harding's commentary.

Setting aside for the moment the Historical accuracy of the Flood accounts one way or the other, there's a serious problem with this interpretation... it's based on a fallacy of literary superposition. This fallacy lead to the judgement of modern criticism that Genesis is derived from Gilgamesh simply because they share common details and our earliest copy of Genesis is younger than our earliest copy of Gilgamesh. That's it.

But that's like saying that recent investigations of the JFK assassination are all derived from Mark Lane's seminal tinfoil theorist "Rush to Judgement," which was published in the 1960s, simply because they came later. Obviously, that's not logically necessary.

There is no sound basis for concluding that Genesis is derived from Gilgamesh.

So when Ken Harding makes this error of literary criticism, one wonders what ax he has to grind, even has he's demonstrating Henry Morris' Creationist biases.

Is it too much to ask for scientists to stick to science?

[VadeRetro]

Setting aside for the moment the Historical accuracy of the Flood accounts one way or the other, there's a serious problem with this interpretation... it's based on a fallacy of literary superposition. This fallacy lead to the judgement of modern criticism that Genesis is derived from Gilgamesh simply because they share common details and our earliest copy of Genesis is younger than our earliest copy of Gilgamesh. That's it.

That's probably what the "almost" was about. If you desperately don't want to think the Genesis account is based on the Babylonian story, there's no way to force you because there's no control log of how many times that story was told and to whom.

It's not important to what Harding's saying on that page.

[Sabertooth]

If you desperately don't want to think the Genesis account is based on the Babylonian story, there's no way to force you because there's no control log of how many times that story was told and to whom.

It's not important to what Harding's saying on that page.

It certanly is if Harding's planning on preaching to more than his own choir.

Nor is it desperation to say that there's no basis for claiming that Genesis is derived from Gilgamesh. In fact, the suggestion of desperation is itself emotionally charged. Why not leave all of that, and the fallacious literary presumpions, to the side?

Why inject the non-scientific into a scientific argument? Especially in light of the point Harding makes that Henry Morris has done exactly that...

Henry Morris (one of the founding fathers of the creationist movement), is saying that if the physical evidence suggests that events occurred differently than the accounts spoken of in the Christian bible, then the physical evidence should be rejected out of hand.

It is said that: "When the evidence contradicts the theory, the scientist rejects the theory.  The theologian rejects the evidence."  This is certainly the case with creationism.

When Harding wanders off the scientific reservation to make gratuitous and unfounded comments about the literary provenance of Genesis, he fuels the notion of Creationists that there is a religious component to the scientific arguments against them.

How productive is that?

[VadeRetro]

How productive is that?

It doesn't help you, except to stay focussed on the irrelevant. Nothing Harding is doing gives you grounds for comparing him to the charlatan Morris.

[Sabertooth]

It doesn't help you, except to stay focussed on the irrelevant. Nothing Harding is doing gives you grounds for comparing him to the charlatan Morris.

I'm not an advocate for Morris, you're missing the point entirely.

Harding sullies his scientific argument by not remaining agnostic. That's not irrelevant, that's a major source of the contention with literal Creationists.

Do you want the Creationists' ears open or closed?

If you want them open, why close them with the gratuitous inclusion of the "irrelevant?"

[VadeRetro]

Harding sullies his scientific argument by not remaining agnostic. That's not irrelevant, that's a major source of the contention with literal Creationists.

This is turning into, "That's not how you reach literal Creationists."

You don't reach literal Creationists. I'm here to tell you after over three years of throwing the whole pile at them day after day, you just don't reach them. That's a fact. It's not a consideration in writing articles against their arguments. Rather, it's a fascinating area of Abnormal Psychology.

[SunkenCiv]

Note: this topic is from 7/20/2002. Thanks gcruse.

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[SunkenCiv]

Note: this topic is from 7/20/2002. Thanks gcruse.

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[Lancey Howard]

Catastrophic floods built Grand Canyon

Catastrophic? The result of some ancient sequester?

[SunkenCiv]

Grand Canyon Gorge Is 9 Times Older Than Thought
National Geographic News | 4-9-2008 | Hope Hamashige
Posted on 04/09/2008 1:26:29 PM PDT by blam
http://www.freerepublic.com/focus/news/1999143/posts

and coming soon to a topic near you:

A Grand Old Canyon
by Sid Perkins on 29 November 2012, 3:35 PM
http://news.sciencemag.org/sciencenow/2012/11/a-grand-old-canyon.html