The deepest point on Earth’s continents has been found by scientists. The Denman trough stretches 2 miles below sea level and was found underneath the Antarctic ice. The research discovered the trough in a project to create the greatest detailed map of the land beneath Antarctica.
MATHIEU MORLIGHEM / UCI
BedMachine is a topography map of Antarctica which will show the ridges, trenches, and slopes that make up the entire landscape.
The team is made up of international researchers led by glaciologists from the University of California, Irvine, who are creating a map using data from 19 research institutions over the past 40 years. It used radar and satellite images to work through the thickness of the ice and the land below, which covers an enormous area.
The findings have been published in the Journal Nature Geoscience By Mathieu Morlighem, the lead author of the study. He told Newsweek that he started working on BedMachine by pure accident.
He was creating models of ice sheets with many colleagues from NASA’s Jet Propulsion Laboratory when they ran these models on two glaciers at which time, they realized something was not right. Some of the glaciers they know of are losing mass.
The proceeded to investigate the problem and discovered the model resolution, inaccurate physics, bad forcing, that’s when they realized the shape of the bed was wrong.
According to Morlighem, the scientists realized they wanted better ice sheet models and they needed better maps of the bed beneath. He came up with a new technique to see the ground under the ice.
Satellite data of the changes to the surface, snow accumulation, and lines of radar data need to be applied to areas where radar is not available at this time. The biggest challenge was Antarctica which is massive and larger than the US and Mexico put together.
So using this method for the entire coast was extremely time-consuming, it took approximately 5 years to get to BedMachine.
Once this was accomplished, the researchers were able to find previously unknown features of land below the ice. They found pronounced ridges across the troughs that feed the Ross ice shelf.
Ross ice shelf is the largest in Antarctica and has been a focus of concern to climate scientists. Research indicates it could run the risk of collapsing under projected global warming.
These ridges were unknown and have made this area of the ice sheet extremely resilient to the increase of ocean-induced melting. Morlighem said that working on climate change, they do not have very good news.
That said, they found other areas that they didn’t know would be even more vulnerable to climate change. The other huge surprise, the incredible trough of Denman Glacier.
Scientists were aware this large glacier in East Antarctica had a trough beneath it but they had no idea how deep it really was. Morlighem said there have been several attempts to work it out using airborne radar but as soon as they flew over, the echo masked the bed.
After creating new techniques, the team was able to figure out that Denman reached 3.5 kilometers or 2.17miles or 11,482 feet below sea level which has made this discovery the deepest point on land.
The Denman Glacier flows through a very deep canyon more than 3,500m below sea level. BedMachine showed that the bed beneath the ice stream is the deepest continual point on Earth!
The troughs and fjords are actually typical of glacial landscapes. Glaciers flow, advance, and retreat causing curvatures in the bed and therefore over thousands of years, they can develop very deep valleys, depending on the rate of erosion.
The deepest point on Earth is not just its continents but the Challenger Deep in the Mariana Trench which stretches to a depth of approximately 36,200 feet or almost 7 miles!
BedMachine should help scientists forecast in a better way how Antarctica will respond to climate change in the coming years. By understanding the landscape below, they can form more accurate models to address future warming.
Morlighem is an ice sheet modeler so he wanted to see how this map affects the projections of sea level. He further said, it will always be a work in progress and it will get better as they gain more data. He plans on maintaining it over the foreseeable future.