Just an update/adding to the catalog -- no ping.
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Posted on 11/05/2003 6:29:54 AM PST by blam
Source: Pacific Northwest National Laboratory
Date: 2003-11-04
Sky-high Icebergs Carried Boulders From The Rockies To In South-central Washington
Seattle -- Geologists have uncovered a scene in the Pasco Basin west of the Columbia River in Washington state that shows how boulders piggybacked icebergs from what is now Montana and came to rest at elevations as high as 1,200 feet.
Although glacial deposits of rocks and boulders are common, especially in the upper Midwest, "There probably isn't anyplace else in the world where there are so many rocks that rafted in on icebergs," said Bruce Bjornstad, a geologist at the Department of Energy's Pacific Northwest National Laboratory in Richland, Wash.
Bjornstad presented his team's results at the Geological Society of America Annual Meeting in Seattle today.
The rocks were left after ice dams holding back a huge lake near Missoula, Mont., broke, re-formed and broke again from 1 million to 2 million years ago to as recently as 13,000 years ago. The floodwaters backed up at the downstream end of the Pasco Basin behind Wallula Gap, a narrow ridge opening through which the Columbia River flows today. The lake lapped the gentle slope of Rattlesnake Mountain, northwest of the gap and part of the Hanford Reach National Monument in south-central Washington Rattlesnake Mountain was the highest peak protruding from the 800-foot-deep temporary body of water, dubbed Lake Lewis. The rocks and boulders, so-called erratics, grounded as the waters of Lake Lewis receded after a few days like a slowly draining bathtub.
Bjornstad led a team that surveyed and analyzed the mostly-granite-strewn debris fields over 15 square miles of Rattlesnake Mountain. He said that the ice-rafted debris left deposits of three types: widely scattered rocks and boulders, distinct clusters and "bergmounds" – low, cone-shaped clumps of erratics that, like a moraine left by glaciers, alter the topography. Bjornstad's group discovered rafted rocks as long as 14 feet.
The erratics were concentrated along northeast-running gullies. Bjornstad suggests that the speed of the flowing water varied as it crossed an uneven surface, and that may have created eddies that forced an ice jam in the deeper, quieter waters at the back of these gullies. The erratics and bergmounds decreased as the surveyors worked up the mountainside. Bjornstad attributed the lower number to smaller successive floods.
Bjornstad and his colleagues found that most of the erratics were rounded, showing the effects of weathering and suggesting that they were carried in by older Ice Age floods.
Collaborating with Bjornstad on the study were Elysia Jennett, Northern Arizona University, Flagstaff; Jenna Gaston, U.S. Fish and Wildlife Service, Hanford Reach National Monument, Richland; and Gary Kleinknecht, Kamiakin High School, Kennewick, Wash.
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Pacific Northwest National Laboratory is a Department of Energy Office of Science research facility that advances the fundamental understanding of complex systems, and provides science-based solutions to some of the nation's most pressing challenges in national security, energy and environmental quality. The laboratory employs more than 3,800 scientists, engineers, technicians and support staff, and has an annual budget of nearly $600 million. Battelle, based in Columbus, Ohio, has operated PNNL for the federal government since the laboratory's inception in 1965.
and besides that, why shouldn't "Dawn", or "Mop 'n' Glo" have mountain ranges named after them, too? ;')
They do ... you just don't pronounce them correctly.
Also, when did "sky high" become a scientific term?
In high school, ever since the headline writer encountered his first bong.
Is there a major peak in the Cascade Range that isn't volcanic in origin?
Not since I left Washington.
Oh wait... the mountains I'm thinking of are in the other western "W" state...
Wow man! I, like, got that one! heh heh
Heh... yeah, I thought up that joke back in nineteen-seventy... uh... nineteen-seventy... hmm... nineteen-seventy...
You could have a rock festival.
Thats a Stone Cold Idea!
Experts Seek Trail to Mark Ice Age Floods (National Park Service Study)
Yahoo News | 11/10/03 | Joseph B. Frazier - AP
Posted on 11/10/2003 7:55:28 PM PST by NormsRevenge
http://www.freerepublic.com/focus/news/1018958/posts
Interesting idea that boulders rode on top of glaciers. Should we ask how these boulders got on top of glaciers in the first place?
Really severe frost heave?
Driving Route 12 through the Palouse is magical - the landscape seems surreal.
Just an update/adding to the catalog -- no ping.
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