Antarctic subsurface canyon could be larger than the Grand Canyon

BBC : Princess Elizabeth Land is a relatively unexplored region of Antarctica, but its surface has hints of a buried canyon network over 1000 km long and up to 1 km deep. The network also appears to connect to a subglacial lake with a surface area of nearly 1250 km². A comprehensive geophysical survey of the region is now under way. Scientists who are part of an international team are flying sensors back and forth across the continent using various imaging technologies to map the subsurface topology. The effort is intended to complete the subsurface mapping of Antarctica; aside from Princess Elizabeth Land one other major unmapped area, Recovery Basin, is included in the current mapping project. Having a full picture of the topology of the rock bed underlying the surface ice is necessary for developing accurate models of glacier and ice-sheet movement.