Researchers have discovered a massive ancient subglacial trough that's far bigger than the Grand Canyon, under the ice of Antarctica.

Scientists from Newcastle University, the University of Bristol's Glaciology Centre, the British Antarctic Survey and the universities of Edinburgh, Exeter, and York discovered the enormous valley during three seasons of charting the Ellsworth Subglacial Highlands, an ancient mountain range buried below several kilometers of Antarctic ice, using data from satellites and ice-penetrating radars.

"We had acquired ice penetrating radar data from both ends of this huge hidden valley, but we had no information to tell us what was in between," said Neil Ross, lecturer in Physical Geography at Newcastle University and lead author of the paper, which was published in the Geological Society of America Bulletin.

The massive valley, which has been dubbed Ellsworth Trough by the research team, is up to 3 kilometers deep, more than 300 kilometers long and up to 25 kilometers across. It is so large, researchers say it can be seen from space through its effect on the surface contours of the ice sheet above it. "Satellite data was used to fill the gap, because despite being covered beneath several kilometers of ice, the valley is so vast that it can be seen from space," said Ross.

The mega-canyon is believed to have been created when, 80 million years ago, Antarctica broke apart from the giant continent it was once a part of, spinning southward at a pace of 16 cm per year. The rift created long valleys and chasms across the warm landscape but when the climate began to cool, glaciers appeared carving out deeper chasms. The glaciers grew deeper and wider eventually creating the present day Antarctica and obscuring the mountain ranges beneath it.

"While the idea of West Antarctic Ice Sheet growth and decay over the past few million years has been discussed for decades, the precise location where the ice sheet may originate from in growth phases, and decay back to in periods of decay, has not been known," said Martin Siegert, professor of Geosciences at the University of Bristol. "By looking at the topography beneath the ice sheet using a combination of ice-penetrating radio-echo sounding and satellite imagery, we have revealed a region which possesses classic glacial geomorphic landforms, such as u-shaped valleys and cirques, that could only have been formed by a small ice cap, similar to those seen at present in the Canadian and Russian High Arctic."