Scientists have discovered a long-lost landscape that’s been preserved beneath the Antarctic Ice Sheet for 30 million years.

Erosion by ancient rivers appears to have carved large, flat surfaces beneath the ice in East Antarctica between 80 million and 34 million years ago. Understanding how these features formed, and how they continue to affect the landscape, could help refine predictions of future ice loss, researchers reported July 11 in the journal Nature Geoscience.

“We’ve long been intrigued and puzzled about fragments of evidence for ‘flat’ landscapes beneath the Antarctic ice sheets,” study co-author Neil Ross, a geophysicist at Newcastle University in the U.K., said in a statement. “This study brings the jigsaw pieces of data together, to reveal the big picture: how these ancient surfaces formed, their role in determining the present-day flow of the ice, and their possible influence on how the East Antarctic Ice Sheet will evolve in a warming world.”