Cambridge scientists’ ‘MRI scan of the Earth’ reveals extraordinary ice age landscapes beneath North Sea
Cambridge scientists have carried out something akin to an ‘MRI scan of the Earth’ to reveal remarkable ice age landscapes beneath the North Sea.
The discovery, made using 3D seismic reflection technology, offers new insight into how ice sheets reacted in the past to a warming planet - information that could help the researchers predict how those in Antarctic and Greenland could be impacted by climate change.
The international team, including British Antarctic Survey and University of Cambridge scientists, found huge seafloor channels each 10 times wider than the River Thames.
These previously undetectable landscapes formed beneath the huge ice sheets that covered much of the UK from thousands to millions of year ago.
The ‘tunnel valleys’, which are buried hundreds of metres beneath the North Sea floor, are the remnants of giant rivers that acted like a plumbing systems for these ancient ice sheets as they melted amid rising air temperatures.
James Kirkham, from BAS and the University of Cambridge, who is lead author of the paper published in Geology on the research, said: “The origin of these channels was unresolved for over a century. This discovery will help us better understand the ongoing retreat of present-day glaciers in Antarctica and Greenland.
“In the way that we can leave footprints in the sand, glaciers leave an imprint on the land upon which they flow. Our new cutting edge data gives us important markers of deglaciation.”
Industry partners provided the technology for the work, which uses sound waves to generate detailed three-dimensional representations of the ancient landscapes beneath the Earth’s surface, in a manner comparable to how magnetic resonance imaging (MRI) scans image structures within the human body.
Incredibly, the technology is able to image features as small as a few metres in size - even if they are buried under hundreds of metres of sediment.
Comparing the ‘ice fingerprints’ to those left beneath modern glaciers enabled the team to reconstruct how the ancient ice sheets behaved as they receded.
Dr Kelly Hogan, co-author and a geophysicist at BAS, says: “Although we have known about the huge glacial channels in the North Sea for some time, this is the first time we have imaged fine-scale landforms within them.
“These delicate features tell us about how water moved through the channels - beneath the ice - and even how ice simply stagnated and melted away. It is very difficult to observe what goes on underneath our large ice sheets today, particularly how moving water and sediment is affecting ice flow and we know that these are important controls on ice behaviour.
“As a result, using these ancient channels to understand how ice will respond to changing conditions in a warming climate is extremely relevant and timely.”
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