‘MRI’ scan reveals spectacular ice age landscapes beneath the North Sea

Spectacular ice age landscapes beneath the North Sea have been discovered using 3D seismic reflection technology.  Similar to MRI (magnetic resonance imaging) the images reveal in unprecedented detail huge seafloor channels - each one 10 times wider than the River Thames.

For the first time an international team of scientists can show previously undetectable landscapes that formed beneath the vast ice sheets that covered much of the UK and Western Europe thousands to millions of years ago. These ancient structures provide clues to how ice sheets react to a warming climate. The findings are published this week (9 September) in the journal Geology.

So called tunnel valleys, buried hundreds of metres beneath the seafloor in the North Sea are remnants of huge rivers that were the ‘plumbing system’ of the ancient ice sheets as they melted in response to rising air temperatures.

Lead author James Kirkham, from British Antarctic Survey (BAS) and the University of Cambridge, says:

“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. ”

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.”

3D seismic reflection technology, which was provided by industry partners, uses sound waves to generate detailed three-dimensional representations of ancient landscapes buried deep beneath the surface of the Earth, in a similar manner to how magnetic resonance imaging (MRI) scans can image structures within the human body. The method can image features as small as a few metres beneath the surface of the Earth, even if they are buried under hundreds of metres of sediment. The exceptional detail provided by this new data reveals the imprint of how the ice interacted with the channels as they formed. By comparing these ancient ‘ice fingerprints’ to those left beneath modern glaciers, the scientists were able to reconstruct how these ancient ice sheets behaved as they receded.

By diving into the past, this work provides a window into a future warmer world where new processes may begin to alter the plumbing system and flow behaviour of the Antarctic and Greenland ice sheets.

Tunnel valley infill and genesis revealed by high‑resolution 3-D seismic data by Kirkham, J. D., Hogan, K. A., Larter, R. D., Self, E., Games, K., Huuse, M., Stewart, M. A., Ottesen, D., Arnold, N. S., Dowdeswell, J. A. (2021) is published in the journal Geology.

Ends

Issued by the Press Office at British Antarctic Survey:

Athena Dinar, British Antarctic Survey, mobile: +44 (0) 7909 008516; amdi@bas.ac.uk

Livia Oldland, British Antarctic Survey, mobile: +44 (0) 7850 541910; livand@bas.ac.uk

Stunning images of the underwater channels and video of lead author James Kirkham explaining the research are available to download here: https://files.bas.ac.uk/photo/deep-sea-channels/

The explainer video will ‘go live’ with the embargo on YouTube here: https://youtu.be/0Vuia0znHik

Gardline is a UK based site survey company that developed the first 3D high resolution seismic system to operate successfully in the North Sea. The data were initially used for hazard assessments at drill sites but it was clear from the outset that the seismic data had far more to offer, particularly in the academic world. The results presented in this paper are ground breaking and new-to-science for which Gardline are very happy to be associated with.

This research was conducted by the British Antarctic Survey in collaboration with the Scott Polar Research Institute at the University of Cambridge, the University of Manchester, the British Geological Survey and the Geological Survey of Norway. The high-resolution 3D seismic reflection data was collected by Gardline Limited on behalf of companies including Harbour Energy, Equinor Energy AS and bp.

British Antarctic Survey (BAS), an institute of the Natural Environment Research Council (NERC) and part of UKRI, delivers and enables world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that uses the Polar Regions to advance our understanding of Earth as a sustainable planet. Through its extensive logistic capability and know how BAS facilitates access for the British and international science community to the UK polar research operation. Numerous national and international collaborations, combined with an excellent infrastructure help sustain a world leading position for the UK in Antarctic affairs.

For more information visit our website www.bas.ac.uk or social media; TW @BAS_news, FB @BritishAntarcticSurvey, LI @british-antarctic-survey, IG @britishantarcticsurvey