Thanks Fred Nerks. From the hard drive, and ultimately from
Science v 295, 11 Jan 2002,p 256-258:
"Kirchner was startled when the nuclide concentrations in the sediments he drew out of streams in 37 different catchments in Idaho's mountains revealed erosion rates over the past 5000 to 2700 years that averaged a whopping 17 times higher than modern-day rates, a finding he reported in the July 2002 Geology. After ruling out climate change and other factors, Kirchner concluded that the huge discrepancy must be due to catastrophic erosion events so rare that decades of regular observations are unlikely to spot them... One lesson to be drawn from this study, Kirchner suggests, is that in young, dynamic mountain ranges, engineers may be greatly overestimating the time it will take reservoirs to fill with debris should one of these catastrophic events occur in the reservoirs' lifetime." -- "Subtleties of Sand Reveal How Mountains Crumble" [related to cosmogenic nuclide dating]
(I was actually browsing for files on the Channeled Scablands flood event, but this one caught my eye)
28 posted on
11/13/2009 7:42:17 PM PST by
SunkenCiv
(https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
The Channeled Scablands
Some researchers have theorized that hundreds of megafloods in a cycle ranging over thousands of years formed the scars in Washington State. Electricity could have carved the region in minutes.
On September 20, 2005, National Public Broadcasting sponsored a NOVA television documentary, “Mystery of the Megaflood.” The program elucidated a theory for how Eastern Washington State was scoured down to the bedrock, leaving formations that geologists find difficult to explain from a uniformitarian perspective. Rather than relying on traditional models of slow, progressive erosion, a catastrophic hypothesis was proposed.
As the theory suggests, during the end of the last ice age, approximately 12,000 years ago, a flood of water taller than mountains swept down through valleys and drainage channels, moving at 120 kilometers per hour. The force of the water was so great that it washed away the forests, the topsoil and any signs of civilization that might have existed in its path. Nothing remained except humps of basalt lava, dry canyons, waterfalls that today have no water and deep chasms that mark where the colossal flow etched into the rocks...
SOURCE
