Collapse of the European ice sheet caused chaos
Scientists have reconstructed in detail the collapse of the Eurasian ice sheet at the end of the last ice age. The big melt wreaked havoc across the European continent, driving home the original Brexit 10,000 years ago.
The Eurasian ice sheet was an enormous conveyor of ice that covered most of northern Europe some 23,000 years ago. Its extent was such that a skier could have traversed 4,500 km continuously across its expanse from the far southwestern isles in Britain to Franz Josef Land in the Siberian Arctic. Its existence had a massive and extremely hostile impact on Europe at the time.
This ice sheet alone lowered the global sea level by over 20 meters. As it melted and collapsed, it caused severe flooding across the continent, led to a dramatic sea-level rise, and diverted mega-rivers that raged on the continent. A new model investigating the retreat of this ice sheet and its many impacts has just been published in Quaternary Science Reviews.
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All rivers in Europe unite
The influence of the Eurasian ice sheet extended far beyond what was directly covered by ice. One of the most dramatic impacts was the formation of the enormous Fleuve Manche. This was a mega-river network that drained the present-day Vistula, Elbe, Rhine, and Thames rivers, and the meltwater from the ice sheet itself, through the Seine Estuary and into the North Atlantic.
“Some speculate that at some points during the European deglaciation, this river system had a discharge twice that of the Amazon today. Based on our latest reconstruction of this system, we have calculated that its catchment area was similar to that of the Mississippi. It was certainly the largest river system to have ever drained the Eurasian continent,” says Patton
The vast reach of this catchment meant that this mega-river had the capacity to contribute enormous volumes of cold freshwater directly into the North Atlantic, enough to have severely modified the Gulf Stream—a major climate influencer.
Also, the sea level rise and the colossal amounts of meltwater discharged from the collapsing ice sheet meant that areas that were previously above sea level eventually became seabed.
“Britain and Ireland, which had been joined to Europe throughout the last ice age, finally separated with the flooding of the English Channel around 10,000 years ago. It was the original Brexit, so to speak,” says Alun Hubbard.
The ice retreats, the humans advance
The ice reconstruction in this study provides a fascinating image of a changing Europe during the time that prehistoric humans came to populate the continent. The environmental challenges they met must have been spectacular.
“One thing that we show pretty well in this study is that our simulation is relevant to a range of different research disciplines, not only glaciology. It can even be useful for archaeologists who look at human migration routes, and are interested to see how the European environment developed over the last 20,000 years,” says Patton.
Read more at Phys.org