Menu
Log in


Buffalo River Watershed Alliance

Log in

Standing on ‘holey’ ground; Hydrogeologist talks about the Buffalo River - Harrison Daily Times

25 Jul 2016 11:31 AM | Anonymous member (Administrator)

Harrison Daily Times

Standing on ‘holey’ ground; Hydrogeologist talks about the Buffalo River


Posted: Sunday, July 24, 2016 7:00 am |

By David HOLSTED davidh@harrisondaily.com |0 comments


PONCA — For Dr. Van Brahana, nothing beats the smell of a good rock.

“I sniff rocks,” he said, then in response to the giggles and chuckles around him, he added, “Not that way!”

Brahana is a hydrogeologist and professor emeritus at the University of Arkansas. As a dedicated rock sniffer, there was no better place to indulge in his guilty pleasure than on a gravel bar along the Buffalo River.

Brahana shared his passion for rocks, particularly the rocks of the Buffalo National River country, in a two-plus hour workshop (it was scheduled for two hours, but get Brahana started on geology and you might as well throw the clocks out the window) held at the Ponca Elk Education Center. Brahana then led a caravan of pebble pilgrims to the Steel Creek area of the Buffalo for some hands-on experience.

The event was sponsored by the Ponca Elk Education Center, a Patagonia environmental grant and the Buffalo River Watershed Alliance.

“I love this area,” Brahana said of the Buffalo River country. “I think it’s spectacular. We need to treat it with the utmost care.”

The workshop dealt with the karst nature of the Buffalo River country. Millions of years ago, according to Brahana, northwest Arkansas lay at the bottom of a shallow ocean. Fossils called crinoids, or sea lilies, have been found in the area that support that claim, said Brahana. The crinoids are also called Indian beads, because the early inhabitants strung them together. Brahana had several examples of the ancient fossils, which he showed to his audience.

Layers of sedimentary rocks, including limestone, chert, sandstone and shale were piled up.

Brahana went on to say that the age of the rocks in the Buffalo National River range from 500 million to 290 million years.

“They were modified into the glorious landscape we have today,”  he said.

Though the Buffalo River lies 100 miles north of the Ouachita Mountains, the formation of that range played a vital role in the present character of the river. Brahana explained that almost 300 million years ago, the upward thrust of the Ouachita’s, fueled by thermal heat, also resulted in lifting the Buffalo River 500 to 600 feet above its original level. The movement also resulted in the fracture and tilting of rock layers in the Buffalo River country.

Millions of years of natural weathering, along with chemical weathering (water soaking into rocks and combining with carbon dioxide to become acidic) have resulted in karstification, or the dissolution of limestone. It’s this karst quality, creating caves, sink holes and “Swiss cheese” openings that is characteristic of the Ozarks, according to Brahana.

“I like to say it’s holey ground,” Brahana said. “The Buffalo River is holey.”

It was this karst aspect that made the Ozarks particularly susceptible to pollution.

“Even small sinkholes allow surface contamination to soak into the rocks,” Brahana said.

Later, while on the banks of the river, Brahana continued to be the voice crying out in the Buffalo River Wilderness.

“Let’s save it for the future, guys,” he said.

Buffalo River Watershed Alliance is a non profit 501(c)(3) organization

Copyright @ 2019


Powered by Wild Apricot Membership Software