Photo credit: Stewart Jamieson
By Shannon Hall
Tucked beneath East Antarctica’s vast ice sheet is a frozen world, complete with subglacial lakes, rivers, basins, volcanoes and mountains. But roughly 91 percent of Antarctica—nearly twice the size of Australia—is unmapped, and the largest unsurveyed region on the icy continent is a region called Princess Elizabeth Land. Now a team of geologists has scoured that area to reveal a massive subglacial lake and a series of canyons, one of which—more than twice as long as the Grand Canyon—could rank as Earth’s largest. The findings indicate the ice sheets are less stable than previously thought, and could be strongly affected by climate change.
Stewart Jamieson from Durham University in England and his colleagues made the discovery by looking for subtle changes in the ice sheet’s surface shapes, developed as a result of ice flowing over diverse topography. For years geologists have thought that hidden features could subtly sculpt the surface above, leaving ghostly hints in the ice. An unwrinkled ice sheet, for example, might reveal a buried subglacial lake whereas an undulating one might signal a hidden mountain range. So with satellite images of such surface features as a guide, Jamieson and his team used ice-penetrating radio waves—which bounce back as echoes, like radar–to help map the topography underneath.
Their analysis, recently published in Geology, reveals a subglacial lake covering as much as 1,250 square kilometers (making it the second-largest subglacial lake in Antarctica by length after Lake Vostok) and a series of canyons that extend a kilometer deep and 1,100 kilometers across. It is a tantalizing first glance at such an uncharted region, says Dustin Schroeder of Stanford University, who was not involved in the study.
Continue reading by clicking the name of the source below.