Dramatic ice deposits on Mars

The slope rises as high as London's Big Ben tower. Beneath its ruddy layer of dirt is a sheet of ice 300 feet thick that gives the landscape a blue-black hue... Planetary scientists located eight of these geological features, called scarps, on the Red Planet...

Open University's Matt Balme, a planetary scientist in Britain who did not participate in this study, said the key findings were the color images of a bluish tint. That indicates a sub-layer that is “somehow compositionally different” than the red dirt. It is unlikely that the frozen sheets are a mix of water and soil. “If the conclusions of the paper are correct,” he said, “you’re looking at something that's almost pure ice.”

The scarps exist along the planet's middle latitudes, ruling out glaciers that migrated from the poles. The study authors propose that these ice sheets formed when thick snows blanketed Mars.

More at The Washington Post.