The unique landscape in the Suwalki area was created by a gigantic flood
One of the five largest known megafloods in world history occurred in the Suwalki region several thousand years ago. Its effects can still be seen today. A breakthrough discovery by scientists at Nicolaus Copernicus University is changing thinking about the landscape of Central Europe and explains m.In. The genesis of Lake Hancza.
15-17 thousand years ago, during the Ice Age, one of the five largest known floods in Earth’s history passed through the region of present-day Suwalki. SourceoThe source of this water was a melting ice sheetod. PowoThis road carried with it 2 million meters ofoin cubic meters of water per second. That’s 10 times the average flow of the Amazon River, or 2,000 times the amount of water that flows on average from the Vistula into the Baltic Sea. Such a floodoThe gloom probably lasted only a dozen days, but its effects can be seen to this day in the landscape of Central Europe – including ponortheastern Poland.
The fact that such a powoThe event happened in the Pleistocene, researchers from the Nicolaus Copernicus University in Torun have just announced to the world in the pages of the journal "Earth-Science Reviews". This gives us a completely different perspective on someore geological structures in the landscape of Central Europe.
– This research sheds new light on how the prairie system in Poland was formed – moPAP dr. hab. Piotr Weckwerth, prof. UMK, first author of the publication. As he adds, the research also explains m.in. The origin of Hancza – the deepest Polish lake.
Several thousand years ago, the ice sheet receded from the area of present-day Polandod Scandinavian. The amount of ice, whichohe accumulated was unimaginable: in its central part the thickness of the ice was 2-3 km, and at the edge the thickness of the ice reached about 250-300 metersow.
It can be assumed that lod then covered vast regions of Poland in poNorth of Poznan, Szczytno or Suwalki. When such a landmassod melted, sometimes under the ice or on its surface lakes were formed, in which theorich water accumulated for a long time.
The flooding in the area of today’s Suwalki probably occurred when the bottom of one such giant glacial lake split open. The water began to escape from it at a gigantic speed. – Such a lake could have had approx. 30 km in diameter – mowi prof. Piotr Weckwerth.
The place in whichoAccording to the findings of the study, the water fell from the surface of the glacier towards its base and further into the foregroundoThe research was carried out by scientists from the Nicolaus Copernicus University.in. Lake Hancza – the deepest lake in our part of Europe. – There you can see traces of strong erosion under the ice caused by water, whichowhich cut the ground with great force and ejected material outside the front of the ice sheet,” says another author of the paper, Prof. Wojciech Wysota.
During the flood, the area was inundated by water more than 20 meters deepoin whichohe lake flowed at a speed of over 55 km per hour. The water followed a system of pre-valleys to the southwestod – first in the direction of today’s Biebrza, Narew, and further – in the direction of today’s Germany, the Sea of PoThe river is located on the North Sea, the English Channel, all the way to the Bay of Biscay – explain the scientists. (Sea PoNorth and the English Channel in theoat the time they were not hidden under water, but constituted land).
This gigantic powoThe sound from several thousand years ago was discovered by chance. – I was browsing the Geoportal, where the m is presented.in. lidar relief image. Detailedomy attention was drawn to theowas the Suwalki region. Suddenly I understood something: I saw the forms thatore resembled something familiar,” says Prof. Wysota.
As he explains, river bottoms sometimes form – e.g. in the sand – characteristic wrinkles of a few centimeters – the so-called “sand”. ripelmarka. When he watched the lidar image of the area to the south of Lake Wigry, he saw similar shapes in the relief, only much, much larger: each such wrinkle was up to 8 metersoin the amount of. And this meant that once flowed here mnotion of water.
Prof. Wysota knew how, in light of the latest research, to explain the existence of such huge riplemarkow: similar forms were observed in Washington state in the US or in the Altai Mountains. There they were described in detail and it was shown that they were formed as a result of great glacial floods. And this meant that we had to deal with a similar flood roalso in our part of Europe.
Thanks to the parameter analysisoin these wrinkles, scientists were able to determine how much water must have flowed that way and how it ran in that area of the floodsodź. The puzzle has begun to come together.
Dr. hab. Piotr Weckwerth says that until now, the origin of the Warsaw-Berlin and Torun-Eberswalda proglacial valley system was a mystery – rownoleżnych depressions of terrain in Poland and Germany. – The system of pradolins must have been formed by the flow of large quantities of water. However, no one knew where it would come from. We provided evidenceow that there were massive and catastrophic glacial floods, whichoThe area was flooded by water accumulated in lakes on the surface of the ice sheet. They gave mnostwo of water, whichora was shaped by a network of valleys and pre-valleys,” he says.
As he adds, there is evidence that such floods, whichorych sourcesosource was the landmassod, renewed and occurred cyclically, also in other areas poNorthern Poland.
As part of a grant from NCN OPUS 16, Dr. hab. Piotr Weckwerth and his team will conduct a more detailedohe latest research on the occurrence of such glacial floods in the Pleistocene.
Sourceosource: PAP – Science in Poland. In the photo, Lake Hancza. Photo. CC BY-SA 3.0/ Wikimedia Commons/ Wojciech Zabolotny