Whoops! Even your comrade evolutionary geologists think the Grand Canyon itself could have formed much more quickly than the standard theory:
http://www.zillmer.com/Grand_Canyon_Erosion.htm
BEGIN UPI STORY
Catastrophic floods built Grand Canyon, research suggests
Copyright © 2002, United Press International
GRAND CANYON NATIONAL PARK, Ariz. (July 20, 2002 10:07 p.m. EDT) - 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.