It’s interesting what happens when people look at a place with new eyes.
When West Virginia University geologists Graham Andrews and Sarah Brown went to the African nation of Namibia, they planned to study volcanic rocks. But before they could get started on their volcanic rock studies, they noticed something interesting.
While exploring deserts in southern Africa, they found a peculiar, yet somehow familiar land formation: flat desert scattered with hundreds of long, steep hills.
“We quickly realized what we were looking at because we both grew up in areas of the world that had been under glaciers, me in Northern Ireland and Sarah in northern Illinois,” said Andrews, an assistant professor of geology at WVU. “It’s not like anything we see in West Virginia, where we’re used to flat areas and then gorges and steep-sided valleys down into hollows.”
What Andrews and Brown saw in the African desert was a bumpy landscape shaped by drumlins, a type of hill often found in places once covered in glaciers. Needless to say, this is not a typical finding in deserts. After the two returned home, Andrews began researching the origins of the Namibian drumlins, only to find out that they’d never been studied.
“The last rocks we were shown on the trip are from a time period when southern Africa was covered by ice,” said Andrews. “People obviously knew that part of the world had been covered in ice at one time, but no one had ever mentioned anything about how the drumlins formed or that they were even there at all.”
Andrews recruited WVU geology senior Andy McGrady to measure the shapes of the drumlins to determine if they showed any patterns that would reflect regular behaviors as the ice formed them. Normal glaciers don’t move much, Andrews said, but the drumlins in Africa featured large grooves, which showed that the ice had to be moving quickly to carve them. The grooves demonstrated that the ice stream occurred during the late Paleozoic Age, about 300 million years ago.
“This ice carved big, long grooves in the rock as it moved,” Andrews said. “It wasn’t just that there was ice there, but there was an ice stream. It was an area where the ice was really moving fast.”
Their findings also confirmed that southern Africa was located over the South Pole during the Paleozoic Age. “These features prove yet another tie between southern Africa and South America to show they were once joined,” Andrews said.
Photo: A WVU field trip to Namibia led to the discovery of drumlins, hills formed in places once covered by glaciers. Photo courtesy of WVU