‘It should be glittering mica, and if it has a nice quartz vein right through it, it should be beautiful. Kids like that.’
- Barbara Frank, “The Rock Doc”
A propitious July 4 meeting between some of the members of the Great Falls Freedom and Defense Memorial Committee and a Great Falls geologist known as “The Rock Doc” has resulted in a hunt for three “indigenous” rocks that can be moved to the Great Falls Library to become the central focus of the memorial that is planned there.
If it happens, it will be the ironic culmination of committee founder Pete Hilgartner’s laconic suggestion last October that “we could just roll a big rock” to the side of the Village Green.
From there, the committee initially proposed a shiny black polished granite or marble, something having the quality of a federal memorial.
But individual voices spoke out in favor of a natural rock; possibly one from the Potomac River Gorge, that would be a part of Great Falls.
On July 4, committee member Glen Sjoblom met Barbara Frank, a University of Maryland geologist, who was selling copies of her new children’s book about Great Falls Park called “The Pothole Mystery.”
She suggested using indigenous rock for the memorial Sjoblom was designing.
“I’d notice the potholes in Riverbend Park and Great Falls National Park,” Frank said. “I’d be amazed at people walking past this really neat stuff. The potholes tell you where the river used to be.
“It occurred to me it [the memorial] should be a rock from the area; not just any old rock, but something indigenous to the area,” she said.
“At Great Falls, the Gorge is carved into metasedimentary rocks.
“Even kids can see that we have rocks that are very old,” Frank said.
The metamorphic rock [here is] the remnants of a mountain range that was formed from 500 to 200 million years ago.
“It was rather spectacular.
“The African plate collided with the North American plate and folded up the pre-existing sedimentary rock, and that metamorphosed them,” she said.
“The key is the micas. When you are walking through Great Falls, you can see the micas. The rocks glitter.”
“The micas in a metamorphic rock have this appearance [because] when the rock is squeezed, it is a new texture that forms in the rock. It’s called ‘foliation.’ The flat minerals are the ones that create this foliation.
“These micas, randomly distributed in the rock, lie down and give this folded nature and new texture.
“The rock looks like what happened to it; it looks squeezed,” Frank said.
“What would be nice for the memorial would be to get a rock that has a quartz vein in it. The cracks opened up, and quartz was deposited in it. It has a history to it.
“It should be glittering mica, and if it has a nice quartz vein right through it. It should be beautiful. Kids like that.
“I take them to Difficult Run, and they are so surprised they can see quartz out in the open.”
“It could be very educational for the kids and the adults to realize this is old rock that has been heated up to temperatures of 600 degrees centigrade,” she said.
“The rocks are kind of neat-looking for sure”
(Her Web address is www.doc-rock.com.)