A massive system of canyons and lakes has been discovered under the ice in Antarctica according to a recent article in Geology. The sub-glacial canyon feature is 1,100 km long and 1 km deep in some locations. This system of canyons and lakes may be largest sub-glacial drainage network under any presently existing ice sheet.
The canyons are likely controlled by tectonics such as the East Antarctic rift system as well as the result of East Antarctica colliding with West Antarctica to form the modern continent. River systems then began to erode the areas of lower topography further downward, before any ice accumulated on Antarctica. Finally, after the formation of the Antarctic ice sheets, flowing water under the ice further deepened the canyons.
The authors conclude that the sub-glacial lake that was discovered may be the last large sub-glacial lake to be discovered in Antarctica.
Jamieson, S.S.R., Ross, N., Greenbaum, J.S., Young, D.A., Aitken, A.R.A., Roberts, J.L., Blankenship, D.D., Bo, S., Siegert, M.J., An extensive subglacial lake and canyon system in Princess Elizabeth Land, East Antarctica. Geology, doi: 10.1130/G37220.1.