The Deepest Point on Land Is Hidden Beneath an Antarctic Glacier

Photo credit: M. Morlinghem et al 2019
Photo credit: M. Morlinghem et al 2019

From Popular Mechanics

  • The deepest point on land, a trough 2 miles below sea level, has been discovered below a glacier in Antarctica.

  • The location and details of the trough were revealed Dec. 12 in the journal Nature Geoscience and presented at the American Geophysical Union Fall Meeting in San Francisco on Dec. 13.

  • Scientists cobbled together radar data, snow accumulation measurements, and surface motion data in order to chart the previously undiscovered valley.

Scientists have plumbed the deepest depths ever discovered on land, and it lies beneath an Antarctic glacier.

Tucked beneath East Antarctica's Denman Glacier, the cavernous trench plunges roughly 2 miles (11,500 feet) below sea level, according to research presented last week at the American Geophysical Union Meeting in San Francisco. Scientists discovered the canyon after they mapped the contours of the chilly continent using a new computer modeling program, called BedMachine. The new map also revealed which glaciers may be more protected from or susceptible to melting in the future due to their underlying topography.

The Dead Sea in the Jordan Rift Valley is the lowest exposed point on land, dipping 1,355 feet below sea level. The deepest point on Earth, however, lies 36,037 feet below sea level within the Mariana Trench in the western Pacific Ocean.

An international team of researchers, led by glaciologist Mathieu Morlinghem of the University of California, Irvine, made the discovery by using a revolutionary new software program, which visualizes where ice meets rock on the continent (see video below). The ultimate goal of the BedMachine Project is to map the glacier-bedrock interface in Antarctica in order to better track rates of melting in the region. Their results were also published Dec. 12 in the journal Nature Geoscience.

When the BedMachine models weren’t lining up with what scientists had previously charted, Morlinghem knew something was amiss. “After months of investigation, we realized that it was not because we were missing important processes. It was because the bed topography under the ice was missing many important features such as troughs, ridges, valleys, etc,” he told CNN.

The team wove together snow accumulation data along with seismic, radar and high-precision surface motion data from 19 scientific research institutions in order to build a better picture of the continent's bedrock. They also worked in ice flow data, which allowed them to better visualize how glaciers and ice sheets flow over and around certain topographic features.

In addition to discovering the vast canyon, researchers spotted ridges that could help slow the flow of several important glaciers that flow across the Transantarctic Mountains, and identified glaciers—like Pine Island and Thwaites—whose bedrock geology make them more susceptible to retreat and melting.

The new findings will help scientists create more accurate estimates of ice and glacier flow, and, in turn, make sea level rise estimates more precise. Additionally, the scientists hope these techniques could be used to create a more accurate profile of the ocean floor.

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