Newly discovered marks in the seas reveal it Slink of large icebergs In front of the beaches of the United Kingdom. According to British Antarctic Survey (PAS) scientists, scraping brands show the place where the lower part of these glaciers was dragged at the base of the North Sea 18,000 to 20,000 years ago.
It The first clear proof of terrible snow blocks They wandered in this area – less than 145 kilometers from the British coast – offers valuable data for how I can change Icy terrain of Antarctica Because the continent is hot.
“We are talking about the big flat ceiling or ‘table’ glaciers“Marine earth physicist James Grgham explains BAS’s, referring to the icebergs that caused deep fur.” In a conservative way, they were measured between five to a few tens of thousands of kilometers – compared to the surface of a medium -sized British city, such as Cambridge or Norwich – and two hundred meters thick. “
When were the icebergs in the North Sea?
Buried under the current seabed is preserved in the seeds, this plow brands are previously For the last glacierA snow layer, which includes most of the British and Irish Islands, has been left with overheating.
They were first detected on operating systems Petroleum and gas drilled In the witch grounds located between Scotland and Norway. In this area, the individual fur formed by small glaciers has already been detected, but the widths of the width of the witchcraft show show that there are huge table glaciers.
Table glaciers come from the snow sites, the floating ends of the iceberg They have separated themselves from the earth to lead to the sea. Therefore, researchers can reduce the existence of these structures in the British and Irish ice layer.
Kelly Hogan, published in the ‘Nature Communications’ magazine, explains how the pass and co -writer’s marine earth physics, which provides historical traces. “We can document with our data The catastrophic decline of these sites At the end of the last glacier era, “for about 18,000 years, we found the change of plowing brands recorded in the seabeds, and the magnificent table icebergs – produced by the natural lifestyle of the snow sites – a large number of and small glaciers The snow sites were corrupted“.
What does it mean about the Antarctic ice layer?
Ice sites Is important to the stability of the snow layerExplains the bass. They support and retain the iceberg snow, otherwise the sea will exit very fast. The regular detachment of the table glaciers on the edge of the platforms – it sometimes only occurs only every few decades – helps keep the iceberg in a stable position behind them.
75% of the Antarctica Surrounded by these floating sites. But it is not clear how the frozen continent moves Climatic change Causes by man. The most important example of the deformation of a snow site to date is what happened with the snow -site Larson B. In 2002, an increase in air temperature melted a portion of the surface of the ice base, sent the platform shore water, and break the ice in a week.
After the degeneration of the snow site, Retained glaciers It has increased its speed several times behind it and accelerated its contribution Increase at sea level. The old brands of the North Sea Plow say that the phenomenon is huge, and the British and Irish snow layer quickly reduced to 200 and 300 meters per year on its edges.
This rapid withdrawal is a mystery that still lasts It was caused by the decline of its snow sites Or if the fragment is a sign of mass losses of the ice layer that is already going on. But a better dating sedresses may give the answer.
“This is an interesting issue. This takes us To the heart of the influence of snow sites In the modern Antarctic ice layer. If we notice a similar change from large table glaciers to small glaciers, we may indicate that the continent is going to experience a significant and rapid mass loss, ”says BAS’s co -editor Rob Larter.
