Massive Landforms Lurk Beneath the Antarctic Ice Sheets

There are enormous landforms underneath the ice sheets of the Antarctica, some of them as big as the Eiffel Tower, and they are contributing to the thinning ice shelves.

According to a report from Science Daily, a team of scientists led by the Université libre de Bruxelles (ULB) in Belgium and the Bavarian Academy of Sciences in Germany recently found an active hydrological system of water conduits and sediment ridges below the Antarctic ice sheet. These strange subglacial formations -- called eskers -- are estimated to be five times bigger than other similar landscapes.

Forming eskers

One of the features of ice sheets are subglacial conduits that run under it funnelling subglacial melt water towards the ocean. New research revealed that these conduits widen progressively as they approach the ocean.

This widening of the conduit and subsequent decrease of the water's velocity lead to the accummulation of sediments at the conduit's portal. Over thousands and thousands of years, these sediments build up, forming eskers that grow to be massive ridges as big as the Eiffel Tower.

Ancient ice sheets that have exposed eskers include the Scandinavian Ice Sheet, according to a report from Science Alert.

Eskers' role in melting ice shelves

The researchers discovered that these ridges scratch deep incisions at the bottom of the ice as the ice moves over them, creating ice-shelf channels where ice is thinner and more vulnerable to melting from the warmer ocean. It was previously believed that ice-shelf thinning only occurs in the ocean, but the researchers found that the scars from the gigantic landforms below contribute to instability even while its still on land.

"Our study shows that ice-shelf channels can already be initiated on land, and that the size of the channels significantly depends on sedimentation processes occurring over hundreds to thousands of years," lead author Reinhard Drews explained.

The paper detailing the findings was published in the journal Nature Communications.