Colossal old icebergs left grooves on the bottom of the North Sea

In icebergs in the size of the city, which drives past the coast of UK, as ice plates covering large parts of Northern Europe, in Rapid Retreat for approx. 18,000 to 20,000 years ago.

James Kirkham at the British Antarctic Survey and Hans Colleugues has found that the preserved shed marks that these giants were made as their subpages plowed through Seflo sediments. The long, comb -like features are buried under mud in the North Sea, but are visible in the seismic study data collection to search for oil and gas.

“We can, from the scope of the sheds and what is about old sea level, that these Bergs are probably five to a few tens of thousands of kilometers wide and perhaps a couple of hunted meters thick-ice on the scale of a medium-sized British city,” says Kirkham.

In Antarctica, table -shaped or countertops are icebergs spectacular vision. Some, like the recent Behemoths that are Nown like A23A and A68A, would compete with even small American areas in the area. The calves from ice shelves – the wide, floating projections of glaciers flowing from the country into the sea.

The recognition that tabular icebergs once connected to the North Sea are thus a clear indication that a British and Irish ice sheet also had ice shelves. And that means there may be some lessons for the future Antarctic decline, says Kirkham.

In the North Sea, they are straight tram lines for the large icebergs overwritten by Squiggly Trough made of the narrow clubs with much smaller ice blocks. In other words, there is a “regime change” where large icebergs are replaced by countless little icebergs when the ice shelves are crushed in rising temperatures, Kirkham says.

RadioCarbon -dating the sediments show this shift that occurs over a period of 20,000 to 18,000 years ago.

The observation raises doubts about the idea that calving Mega-Bergs such as A23A and A68A can report the widespread collapse of Antarctic ice shelves.

Emma Mackie at the University of Florida has tracked Tabular Iceberg size in satellite data from the mid-1970s onwards that the trend is essentially flat.

“James’s research emphasizes mine, which is that broad calving events are not needed for a sign of instability or cause of alarm,” says Mackie. “On the contrary, Disint signed via death with a thousand cuts. We should be concerned when we stop seeing the big calving events.