Researchers at NASA have discovered a huge upwelling of hot rock under Marie Byrd Land, which lies between the Ross Ice Shelf and the Ross Sea, is creating vast lakes and rivers under the ice sheet. The presence of a huge mantle plume could explain why the region is so unstable today, and why it collapsed so quickly at the end of the last Ice Age, 11,000 years ago.

Mantle plumes are thought to be part of the plumbing systems that brings hot material up from Earth’s interior. Once it gets through the mantle, it spreads out under the crust, providing magma for volcanic eruptions. The area above a plume is known as a hotspot.