The discovery of huge landforms under the Antarctic ice helps us to understand how landscapes are shaped by melting ice.
An international team of researchers has discovered huge landforms under the Antarctic icecap.
Some are as high as the Eiffel Tower. And may contribute to the thinning of the Antarctic ice sheets.
The fact that huge landforms can be formed under ice caps has been known for some time now. We know, among other things, thanks to the huge ice caps that once covered Scandinavia and North America, but eventually disappeared.
They left different land shapes. Think of landscaped canals or sediments built hills. These lands are formed by melting water that was formed under the icecap and ran away from the icecap.
Although we often see such landforms in places where ice is located, we have never spotted them under an existing ice. It’s also not so crazy: the landforms are often quite small and buried under miles of ice. And yet, an international team of researchers has now succeeded in detecting landforms under the Antarctic icecap. And those landscapes prove to be huge.
They are about five times larger than the landforms we find in places where ice was once and sometimes as high as the Eiffel Tower.
IN THE PICTURE
In the picture at the top of this article, you can see an esker in Sweden. This was a long time under a thick pack of ice. When the ice melted, the box esker emerged.
Meltwater channels and eskers
What kind of landforms should you think about? Well, for example, subglacial meltwater channels. These tunnels often have a diameter of several meters to several tens of meters and bring subglacial melting water to the ocean. The closer the meltwater channels come to the ocean, the wider they become. And the wider the channels become, the slower the melting water will flow and the more sediment will dissipate the melting water.
Over a period of thousands of years, hills built up of sediments are formed under the ice. And those hills – sometimes called eskers – are sometimes as high as the Eiffel Tower, wrote the researchers in the Nature Communications magazine.
The hills of sediments have pretty sharp peaks. And those tops damage the bottom of the ice that slides over these hills. That ice skips towards the sea and eventually becomes part of the ice sheet: the part of the Antarctic icecap resting on the water.
Previous research already showed that this ice cream becomes thinner as soon as it ends up in the (warmer) ocean water. But this research suggests that the ice is already affected and becomes thinner when it is still on land.