The canals – ten times wider than the Thames – once drained meltwater and may provide more insight into how today’s glaciers will fare.

We know that glaciers are wasting away at breakneck speed right now. But what exactly happens beneath these huge moving ice masses can only be guessed at. That may now change. Scientists have created spectacular images of the special landscape in the North Sea. And this landscape is made up of huge channels that formed under the ice sheets that covered much of Europe thousands to millions of years ago.

New images

Scientists have been aware of the enormous glacial channels in the North Sea for some time now. In a new study however, researchers decided to study them more closely. Using 3D seismic reflection technology – comparable to MRI – they imaged these channels in unprecedented detail.

Compared the 3D seismic reflection data with previously collected seismic data from the region. Image: James Kirkham, BAS

More about 3D seismic reflection technology
3D seismic reflection technology uses sound waves to produce detailed, three-dimensional images. The method is particularly useful for studying ancient landscapes buried deep below the Earth’s surface. In a similar way to MRI imaging the human body, scientists can visualize impassable landscapes using 3D seismic reflection technology. Even objects and structures buried under hundreds of meters of sediment can become visible in such images.

The new images show, among other things, that the canals are at least ten times wider than the English River Thames. These enormous channels, buried hundreds of meters below the seabed in the North Sea, are the remains of enormous rivers, the researchers say. These rivers probably formed when ancient ice sheets melted due to rising air temperatures and carried the meltwater long ago.

A map of the North Sea showing the boundary of the last ice sheet and the buried channels. Image: James Kirkham

Origin

The images thus tell us the story of how the until recently enigmatic canals were born. “Its origins had been an unsolved case for more than a century,” said study researcher James Kirkham. But delicate features now show how water moved through the channels (under the ice) and even how the ice melted away. In addition, the images show how the ice and the channels mutually influenced each other.

Insight

This insight is very important if we want to better understand how today’s glaciers will fare. “It’s very difficult to observe what’s happening under large glaciers today,” said researcher Kelly Hogan. “Particularly how moving water and sediment affect the ice flow. We do know that these are very important factors for the way the ice behaves. As a result, it is highly relevant to take the ancient channels as an example so that we can better understand how today’s ice will respond to changing conditions in a warming climate.”

By diving into the past, we therefore also get a better picture of the future. Because the ancient channels provide important clues about how today’s ice sheets will respond to climate change. “The discovery will help us better understand the ongoing retreat of current glaciers in Antarctica and Greenland,” concludes Kirkham. “Like footprints in the sand, glaciers leave an imprint on the land on which they flow. And our new advanced data now provides important insight into the continued decline of glaciers.”