Using an analysis method called seismic reflection, a team of scientists observed the huge grooves left by subglacial rivers buried hundreds of meters below the bottom of the North Sea. A hidden landscape carved in hundreds of thousands of years by natural activity.
“The origin of these channels has remained unresolved for over a century. This discovery will help us to better understand the ongoing withdrawal of current glaciers in Antarctica and Greenland,” said geophysical James Kirkham of the British Antarctic Survey. “The glaciers leave a mark on the earth they’re flowing on.”
Reflective seismics are based on vibrations that propagate underground to trace a footprint of what is at certain depths. How did the researchers detect something like that? Groups of compressed air guns were towed onto a section of the North Sea and sound waves were “shot.”
The latter, while bounced on structures of different density under the bottom of the sea, then returned and were heard by special “marine microphones.” It was in this way that researchers subsequently cleaned and analyzed the high resolution 3D data to build a layered map of the ancient landscape.
The data revealed 19 wide cross-channels between 300 and 3,000 meters. “Although we have long known of the enormous glacial canals in the North Sea, this is the first time we have resumed large-scale morphologies within them,” said geophysical Kelly Hogan of the British Antarctic Survey.
By the way: do you know that a new island has been discovered lately, more north of all the others? While, at one time, there was a piece of land that connected Great Britain and Germany.