- The Washington Times - Tuesday, December 4, 2001

CHARLOTTESVILLE (AP) A maverick geologist is starting to pick up some support for his theory that the Blue Ridge Mountains are still growing.
David Prowell, a geologist with the U.S. Geological Survey in Atlanta for 27 years, said the Blue Ridge Mountains are barely rising a little over 100 feet every million years but enough to offset natural erosion.
The Blue Ridge, the easternmost range of the Appalachians, runs from southern Pennsylvania through Virginia and into northern Georgia.
"They should have eroded away 100 million years ago but somehow they are renewing themselves," Mr. Prowell said.
"I started talking about this 20 years ago, and I had geologists get up and walk out on my talk."
But Mr. Prowell, 52, said that when he spoke on the subject in March last year at the Geological Society of America's Southeastern section meeting in Charleston, S.C., "it was so packed, you couldn't get in the door."
"I think it's a new and unique" theory, said Scott Southworth, a geologist with the U.S. Geological Survey in Reston.
"Mountains don't persist very long. But you look out now and see some pretty high ground" from the Smoky Mountains to the Shenandoah, he said. "People still refer to the Appalachians as very old mountains [but] it's just not true," at least in geological terms.
Scientists have long thought that the Blue Ridge and the Appalachians formed about 300 million years ago, when Africa drifted into North America and buckled the land, forcing it upward and forming the mountain chain.
Mr. Prowell, however, said erosion leveled those mountains. "Erosion can reduce a mountain chain by 90 percent of its height in 20 million years," he said.
About 250 million years ago, the African continent pulled away from North America, leaving "gashes" in the earth that filled with tens of thousands of feet of sediment from the eroding mountains.
Then our familiar Appalachians and the Blue Ridge began forming about 140 million years ago, when a westward push of the continental plate started at the Mid-Atlantic ridge. That compression is still forcing the mountains to rise, though at such a slight rate that it's not easy to discern.
John Dennison, a geologist at the University of North Carolina who agrees with Mr. Prowell's theory, said the movement of the continental plate is "as fast as a fingernail grows."
Mr. Prowell said softer rock under the Appalachians is being pushed against an old land mass in the deep crust that runs in an irregular line from New York to Alabama.
Rocks on the west side of that line are more resistant to compression than rocks east of that line, causing the mountains east of that line to rise.
Mr. Prowell's theory, of course, would mean the Appalachians are relatively young. "The mountains that now exist aren't the ones that were there in the Paleozoic," he said. "These are new mountains."
He is looking for direct evidence to determine the rate of uplift of the mountains. "I want to get direct evidence by looking at sediments still in the Appalachians."
His indirect estimate of the growth of the mountains at 30 to 40 meters every million years is based on studies that show the mountains are being eroded at slightly less than that rate.
"The way geology is, people throw ideas out there and try to support them," he said. "History determines who is right or wrong. The bogus ideas get pushed under the rug."

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