Nasa surveys find frozen world below ice sheet in Greenland
The landscape, a vast expanse of warped shapes including some as tall as skyscrapers, was found using ice-penetrating radar loaded aboard survey flights by US space agency Nasa.
Scientists have discovered a frozen underworld beneath the ice sheet covering northern Greenland.
The findings and the first images of the frozen world more than 1.5km below the surface of the ice sheet were published on Sunday in the journal Nature Geoscience.
Scientists said the findings could deepen understanding of how the ice sheets of Greenland and Antarctica respond to climate change.
"We see more of these features where the ice sheet starts to go fast," said Dr Robin Bell, the study's lead author and a geophysicist at Columbia University's Lamont Doherty Earth Observatory. "We think the refreezing process uplifts, distorts and warms the ice above, making it softer and easier to flow."
Until recently, scientists studying the Greenland ice sheet for evidence of change under global warming had thought the shapes they discerned beneath the ice sheet were mountain ranges.
But with new gravity sensors and radar operating from Nasa's airborne surveys of the ice sheet over the last 20 years, scientists eventually concluded the formations were ice - not rock.