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Deep below the frozen lands of Antarctica, scientists have discovered ancient tectonic plate structures that have a considerable impact on the cast iron patterns around the continent's largest ice shelf.
The hidden rock, in place for hundreds of millions of years, controls the flow of water around Ross's gigantic ice shelf. This plateau currently serves as a crucial buffer preventing more of the Antarctic ice from escaping into the ocean.
The researchers have detected this rock thanks to observations made by IcePod, a dedicated scanning system that measures the height, thickness and internal structure of the pack ice, as well as the magnetic and gravimetric signals of the underlying rock.
The IcePod can essentially scan hundreds of meters of ice to detect underlying rock structures that can not be detected by satellites.
A view of the ice floe of IcePod. (Winnie Chu)
As reported by researchers in their recently published study, a geological boundary between East and West Antarctica has created a sub-continent divide that protects the Ross Ice Shelf from warmer waters and continues to melt.
"We could see that the geological boundaries made the seabed on the eastern side of the Antarctic much deeper than those in the west, and that affects the way the ocean's water flows under the pack ice." says marine geologist Kirsty Tinto of Columbia University.
With the Ross Ice Shelf that slows the drift of about 20% of the submerged ice of Antarctica into the ocean – the equivalent of an overall rise in the sea level of about 11.6 meters or 38 feet – this is an important discovery.
Using the collected geological data and computer modeling, the team found that the tectonic dividing line stopped the warmer waters to the grounding line of the pack ice, where they connect to the bottom of the sea.
At the same time, geologic formations beneath the Ross ice floe can accelerate melting along its eastern edge during the summer months, in part due to an open water region called Ross Shelf Polynya.
"We found that the loss of ice on the Ross Ice Shelf and the flow of the adjacent ground ice are sensitive to process changes along the ice front, such as summer warming in case of decreasing sea ice or clouds, "says one of the team members, a glaciologist. Laurie Padman of the Earth & Space Research Organization in Seattle.
Understanding future melting patterns in Antarctica and their impact on the rest of our planet will require detailed data not only on short-term local conditions near the ice front, but also on broader long-term prospects. the changes occur in the circulation of deep hot water.
And that's the goal of the ongoing ROSETTA-Ice project, which this new study is part of. Work is continuing to observe and measure the melt patterns around the Ross ice floe, which covers about the same area as France, about 480,000 square kilometers (185,329 square miles).
"To understand the Antarctic and its functioning, we must take into account the ice, the ocean, the atmosphere and the geology, as well as their interactions at different distances and time scales," he said. glaciologist Helen Amanda Fricker of the Scripps Institution of Oceanography in California.
"ROSETTA-Ice is a great example of how an eclectic interdisciplinary team can come together to examine a complex system and actually change our understanding of how it works."
The search was published in Nature Geoscience.
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