Scientists have found hidden evidence of ancient ice streams in the African desert


Once, about 300 million years ago, when Southern Africa united in the hip of South America, this now arid region was covered by a vast expanse of glaciers.

You would not know today, looking at the dry volcanic desert of the Twyfelfontein region in northern Namibia. But over its 4.5 billion years of history, our planet has created the habit of reinventing itself.

If we peel the layers, sometimes we can glimpse who they used to be – it would be enough to try.

Geologists Graham Andrews and Sarah Brown are among the first to do so in Namibia, and their latest research has led to an unexpected discovery.

It turns out that this region was once home to a great ice-stream – the arteries that direct the flow from the center of a glacier to its edge – and this was so impressive that it would have rivaled those we see in modern Antarctica.

While exploring the desert country on a field trip, these two geologists from the University of West Virginia noted some peculiar features of the region of steep, steep hills commonly known as the Namibian drums.

"We quickly realized what we were seeing because we both grew up in areas of the world that were under the glaciers, I in Northern Ireland and Sarah in northern Illinois," says Andrews, whose experience is based on the volcanic provinces across the north. American Ridge.

But although the origins of this foreign landscape seemed clear to Andrews, he was surprised to discover that the subject had never been researched.

"People obviously knew that part of the world had been covered in ice at one time, but no one ever mentioned anything about how the drumlins formed or that they were really there," Andrews explains.

Analyzing the shape and size of the unique landscape using Google Earth information, Andrews and his team tried to find out if the drumlins could have been sculpted from the waxing of a now obsolete glacier.

Analyzing their results, the researchers found large, long furrows in the region's rocks. The evidence was clear: this must have been caused by ancient forms of ice that moved very quickly – fast enough that the ice could penetrate the volcanic landscape (about 800 meters per year).

The findings are the first evidence of a huge ice current, responsible for draining the ice cap that covered southern Africa during the Paleozoic Age.

Twisting and turning for about two hundred miles, this stream would have flowed northwestward, emptying the region's ice cap in a shallow marine environment in what is now modern Brazil.

Reconstruction of Gondwana plates during the late Paleozoic at 310 Ma(Kathryn Pauls)

The research not only confirms another link between these two southern continents, but also affirms the location of South Africa 300 million years ago, served by South America just above the South Pole.

"This work is very important because little has been published about these glacial features in Namibia," says co-author Andy McGrady, another geologist at West Virginia University.

"It's interesting to think that this was a groundbreaking work, in a sense, that this is one of the earliest works covering the features of these features and gives some hints as to how they were formed."

This study was published in PLOS Onand.


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