Geologists recently discovered massive canyons and valleys hidden beneath the glaciers of West Antarctica. The largest, the Ellsworth Trough, plunges 2,000 meters (6,561 feet) below sea level.

The trough’s valley is filled with deep ice (3,000 meters or 9,842 feet) as it stretches for 300 kilometers (186 miles) between the ice-encrusted Ellsworth Mountains and surrounding highlands. At its widest, the Ellsworth Trough spans 25 kilometers (15.5 miles). The canyon and valley system runs roughly northwest to southwest and ends by plunging into the sea.

For comparison, the Grand Canyon attains a depth of approximately 1,737 meters (about 1 mile) and extends 433 kilometers (277 miles) through the southwestern United States.

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The ice-filled canyon gives geologists clues about how ice first overwhelmed Antarctica. The frozen coating of western Antarctica may have spread from the Ellsworth Mountains and surrounding highlands. The ice sheet covering the sea may have formed when the growing glaciers from the highlands reached the sea, similarly to the modern-day Antarctic Peninsula. Now, these highlands may serve as anchors for the glaciers and ice sheets as the planet continues to warm.

Scientists mapped the hidden Antarctic troughs using radar to peer beneath the ice, along with satellite images. The Geological Society of America Bulletin published their results.

“To me, this just goes to demonstrate how little we still know about the surface of our own planet,” lead author Neil Ross of Newcastle University, told Forbes.

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Although impressive, the newly discovered Antarctic canyon doesn’t set a world record. In fact, crowning the planet’s deepest canyon poses a problem because surrounding geological features can make defining canyon depth difficult.

Near Arequipa, Peru, Colca Canyon boasts a depth of 4,160 meters as it slithers through the Andes Mountains. In China, the Yarlung Tsangpo Canyon attains a depth of approximately 5,000 meters, if the height of neighboring mountains peaks are included. The Indus River gorge in northwest Pakistan slices even deeper, if the soaring Himalayan mountains on the canyon’s edges are included.

Photo: The Sentinel Range in the Ellsworth Mountains, Antarctica. Credit: NASA/Michael Studinger, Wikimedia Commons